Articles by tag: design

Articles by tag: design

    Finishing the Chassis

    Finishing the Chassis By Kenna and Janavi

    Task: Build a Chassis

    We have been working on this chassis for over 3+. In out last post, we had thought the wheels were ready to go. However, various parts, such as wheel mounts, had been put on backwards or were unusable so we had to do everything over again.
    Now that the robot has wheels, we started on attaching the REV expansion hub and battery. The chassis is square, but has an asymmetrical structure of tetrix bars. Attaching the battery was the simple part since previous version of the robot had a 3D-printed battery holder that would be screwed on. There was no way to effectively place the expansion hub on the tetrix rails. Instead, we attached a thin plank of wood to two parallel bars, drilled a couple holes, and screwed the hub on.
    Overall, it is a very no-frills chassis. We had to cut most of the side shields off because they were becoming more of an obstruction than an aid.

    Next Steps

    Though the physical robot has been built, it has no code. Both of us will be learning how to program a basic pushbot.

    Swerve Drive Experiment

    Swerve Drive Experiment By Abhi

    Task: Consider a Swerve Drive base

    Last season, we saw many robots that utilized a swerve drive rather than the mecanum drive for omnidirectional movement. To further expand Iron Reign's repertoire of drive bases, I wanted to further investigate this chassis. Swerve was considered as an alternative to swerve because of its increased speed in addition to the maneuverability of the drive base to allow for quick scoring due to its use of traction wheels at pivot angles. Before we could consider making a prototype, we investigated several other examples.

    Among the examples considered was the PRINT swerve for FTC by team 9773. After reading their detailed assembly instructions, I moved away from their design for many reasons. First, the final cost of the drive train was very expensive; we did not have a very high budget despite help from our sponsors. If this drive train was not functional or if the chassis didn't make sense to use in Rover Ruckus, we would have almost no money for an alternate drive train. Also, they parts used by 9773 involved X-rail rather than extrusion rail from REV. This would cause problems in the future as we would need to redesign the REVolution system for X-rail.

    Another example was from team 9048 which appeared to be more feasible. Because they used REV rail and many 3D printed parts, this was a more feasible prototype. Because they didn't have a parts list, we had the find the rough estimate of cost from the REV and Andymark websites. Upon further analysis, we realized that the cost, though cheaper than the chassis of 9773, would still be a considerable chunk of our budget.

    At this point it was evident most swerve drives being used are very expensive. Wary of making this investment, I worked with our sister team 3734 to create a budget swerve with materials around the house. A basic sketch is listed below.

    Next Steps

    Scavenge for parts in the house and Robodojo to make swerve modules.

    Swerve Drive Prototype

    Swerve Drive Prototype By Abhi and Christian

    Task: Build a Swerve Drive base

    Over the past week, I worked with Christian and another member of Imperial to prototype a drive train. Due to the limited resources. we decided to use Tetrix parts since we had an abundance of those. We decided to make the swerve such that a servo would turn a swerve module and the motors would be attached directly to the wheels.

    Immediately we noticed it was very feeble. The servos were working very hard to turn the heavy module and the motors had trouble staying aligned. Also, programming the chassis was also a challenge. After experimenting further, the base even broke. This was a moment of realization. Not only was swerve expensive and complicated, we also would need to replace a module really quickly at competition which needed more resources and an immaculate design. With all these considerations, I ultimately decided that swerve wasn't worth it to use as a drive chassis at this time.

    Next Steps

    Consider and prototype other chassis designs until Rover Ruckus begins.

    Big Wheel Ideas

    Big Wheel Ideas By Janavi

    Task: Create a Unique Chassis

    This summer, we're working on creating unique chassis that are outside of our comfort zone. Often we choose safe bases - opting for ones that we have tried in the past and know work. But, taking the opportunity to explore unique bases allows us to see their performance. One of our ideas is for a two-wheeled robot, with two large wheels and one, smaller, non-motorized omniwheel. We think that this 2-wheeled robot would be a good opportunity for Iron Reign, as we know that our robot has to be lighter than the Relic Recovery robot and a non-mecanum drive would be much lighter. Here is a drawing of what we plan the chassis to look like:

    To make this chassis the most efficient based on what we currently know about the competition (light weight robot needed) we are planning to do different tests and calculations to determine the proper motor-gear ratio needed and the wheel locations to properly balance the robot. We also need to perform tests to determine the best material to use for the robot. In the past we've used REV rails for the majority of our structure but due to the weight limit on our robot we plan to minimize metal in our design rather opting for materials that are just as functional but weight less.

    Next Steps

    Perform calculations comparing different motors as well as different wheel ratios to determine the optimal ratios

    Chassis Flyer

    Chassis Flyer By Ethan

    Kraken

    This is Iron Reign’s world-championship robot from last season. The basic rundown is this:

    • Weight - 42 lbs
    • Size - 18x17.8x17.5 inches
    • Drive - Mecanum
    • Main parts kit - REV

    Iron Reign uses two design processes in conjunction with each other to create efficient and reliable parts: iterative, continual improvement and competitive design.

    An example of these design processes working in conjunction is the process of designing our cryptobox intake system. One person had the idea to build an arm-style grabber seen on many current competition robots. His design, however, included shorter arms for space’s sake and a more compact lift system than normal. The second person decided to build a unique conveyor-belt system which used friction to hold blocks in space and move them vertically. Through the competition, we determined that the prior design was more efficient and took up less space than the latter, so we settled on his design, adding in a linear slide for lifting at the end of the process. Then, Kaizen comes in. Through firsthand experience in scrimmages, we learned that the grabber system isn’t as reliable as we thought when first testing. So, we have designed a new grabber system that moves like the arms did previously, but also rotate with soft spikes attached to hold blocks with friction better without damaging them.

    As this soft-spike system ceased to perform to our expectations, we looked to other mechanisms to pick up and deliver blocks effectively. We created a new grabber that still used the rotating systems of the soft-spike, but instead, we used custom 3D printed “octopuckers” which had a much tighter grip on the glyphs. As well, inside the gripper, we created a custom “lift” made out of NinjaFlex so that the blocks could be moved up and down internally in the gripper, eliminating our need for stacking.

    Later, we further improved upon the grabber design, attaching it to a conveyor belt so that we could move glyphs all across our robot in order to score higher, using our REVolution system. This is the most ambitious use of our REVolution system yet, and we strongly encourage the reading judges to view it at the pits.

    BigWheel

    The main purpose of this robot is to see if larger wheels will give us an advantage in the competition. Right now, we’re guessing that the competition field will have debris, and we hope that the large wheels will perform better in this environment.

    • Size: ~18x18 in
    • Wheels - 8in large, regular omni wheels in front
    • Part System: Custom parts

    Garchomp

    For skill development we have newer builders replicating the chassis portion of our competition robot (Kraken). This one will not be weighed down by the additional upper structure of the competition robot and so should be a closer comparison in weight class to most of the other chassis designs under consideration here. Garchomp has a simplistic design and is nothing more than mechanums, rev rails, motors, sprockets, wires, and a rev hub. The large mechanums are held together using side plates from the 2017-18 competition season. These are geared up to neverest 40:1 motors.

    • Size: ~18x18 in
    • Wheels: Mechanum
    • Part System: REV
    • Motors: Neverest 40:1

    Summer Chassis Project - July Meeting

    Summer Chassis Project - July Meeting By Kenna, Ethan, Charlotte, Karina, Shaggy, and Abhi

    Task: Compare & Collaborate on Chassis

    At Big Thought's offices in downtown Dallas, three teams met. Technicbots (Team 8565), EFFoRT (Team 8114), Schim Robotics (12900), and Iron Reign are all part of the North Texas Chassis Project. The goal is for each team to create any number of chassis and improve their building skills by learning from the other teams.

    The meeting began with an overview of all teams' progress. Each team presented their thought process and execution when creating each bot and discussed why/how everything was done. At the end, we all reviewed the rule changes for the 2018-19 season. Once all questions had been asked and answered, testing began.

    Austin Lui of Technicbots gets their chassis ready for testing.

    Using leftover tiles from last season, we set up a small field in Big Thought's blue room. Technicbots provided a ramp to do enhanced testing with. All teams plan on testing:

    • Forward speed
    • 3 second turn
    • Up/Down ramp
    • Balancing stone
    • Weight-pulling
    • Straight line drift
    • 90/180° turn offset

    Connor Mihelic of EFFoRT adds some finishing touches.

    We know from Google Analytics that our website has about 200 visitors a month but we rarely meet the people who read and use our blog posts. Today, we got to meet the mentors of Team 12900 from a middle school in Plano, TX. When they and their students were starting out as a team, they utilized our tutorials and journal. Apparently their teams members are avid followers of our team, which was very meaningful to hear. Some non-FTC friends visited as well and were introduced to cartbot.


    Terri and Grant Richards of Schim Robotics.

    Next Steps

    Using what we learned from the other teams, we will begin to improve all of our chassis. Most of them are at varying levels of completion so now we want to concentrate on getting all of them to the same level of functionality. Garchomp is, notably, the most behind so he will be getting the most attention from here on out.

    C.A.R.T. Bot Summer Project

    C.A.R.T. Bot Summer Project By Evan, Abhi, and Janavi

    Task: Enhance our robot-building skills

    At Iron Reign, we hate to waste the summer since it’s a great time to get all the ridiculous builds out of the way. Thus, we created C.A.R.T. Bot (Carry All our Robotics Tools). Our constant companion these last few seasons has been our trusty Rubbermaid utility cart which has been beaten and abused, competition after competition, as it carried all our tools and robots. Because of all of this, we decided it was time to show the cart a little love, and in typical Iron Reign fashion, we went all out and turned it into a robot.

    Our first step was to switch out the back wheels on it to elf-sized bicycle wheels, allowing us to take on the mightiest of curbs and motorize it. To attach the wheels, a four foot or so cylinder of threaded steel was inserted in holes on either side of the cart. Two slots were cut out in the bottom for the wheels and they were eventually slid on, but not after 3D printed mounts for sprockets were attached to the wheels, enabling us to gear them in a one to one ratio with the sprocket attached to the motors, which consisted of two SIM motors commonly found on FRC robots.

    Before we used SIM motors, we attempted to power the cart using two Tetrix motors which were geared for speed but, due to load, barely moved at all. Besides a lack of power, they also tended to come out of alignment, causing a terrible noise and causing the cart to come to a stall. This was quickly scrapped. To mount the motors, we used two pieces of aluminum bars and bolted them to the motors, then screwed them to the floor of the cart, aligned with the wheels. We chained them together and got about powering the system. We got two 12-volt batteries and chained them in parallel so as to not overload the system, and hooked them up to a REV hub. Then, we ran them through a switch and breaker combination. We connected the motors to the rev hub and once we had it all powered up, we put some code on it and decided to take it for a spin.

    It worked surprisingly well, so we went back in and put the finishing touches on the base of Cart Bot, mainly attaching the top back on so we could put stuff on top of it, and cutting holes for switches and wires to run through, to make it as slick as possible. We added a power distribution station to assist with the charging and distribute current to any device we decided to charge on the cart. We will eventually hook this up to our new and improved battery box we plan on making in the few spare moments we’ll have this season, just a quick quality of life improvement to make future competitions go smoothly.

    Next Steps

    Our cart box isn’t done yet, as we intend to make a mount for a solar panel, which we will be able to charge the cart during the downtime in competitions (only if there’s a good window we can park it next to). The cart wasn’t just about having a cool new and improved cart that we don’t have to push (which it is), it also was a test of our engineering skills, taking things that never should have been and putting them together to make something that we will utilize every competition. We learned so much during this experience, I for one learned how to wire something with two batteries as not to destroy the system, as for everyone else, I can’t speak for all but I think we learned a very important lesson on the dangers of electricity, mainly from the height of the sparks from an accidental short that happened along the way. Despite this, the cart came out great and moves smoother than I ever could have hoped. The thing is a real blast and has provided a lot of fun for the whole team, because yes, it is ridable. We predict the speed it’s set at is only a fifth of its full potential speed, and since it already goes a tad on the fast end we don't intend to boost it anymore while there’s a rider on it. Overall, the project was a success, and I’m personally very proud of my work as I’m certain everyone else is too. Come to see it at our table, I really think it’s worth it.

    Adjusting Garchomp's Chains

    Adjusting Garchomp's Chains By Janavi and Kenna

    Task: Build the Chassis

    In our last post, we thought that we had finished Garchomp. However, as we came back to the next practice, we realized that Garchomp's chains were incorrectly linked.

    So, we started to diagnose the problem. We noticed that the old REV rails we were using had dents in them, which caused the motors to shift, therefore causing the chains to come off the gears.

    To amend this problem, we decided to replace the REV rails ensuring that the motors would not shift during movement. To accomplish this we:

    • First, we loosened all of the screws on the current bar, carefully slid it out, and replaced it with new bars
    • Then we fixing all of the chains and confirming that each of them were individually working
    • we re-attached all of the cables to the robot
    • Ran a stress-tester program and hung the robot on a hook to allow us to properly observe the wheels
    Due to our tests we discovered that our wheels were running at different speeds, meaning that our robot constantly moved in circles. After checking that the motors were working, we discovered that it was our encoder cables that were plugged in wrong. After that, Garchomp began to run smoothly.

    Next Steps

    We will run more stress tests on our robot and make sure that it is up to par with our past robots.

    BigWheel CAD

    BigWheel CAD By Ethan

    Task: Create a mockup for BigWheel

    We've been working on a design for the chassis workshop for quite a while now. We already presented it at the first meeting, and now we need to work on the other components of our presentation: the weight testing, torque calculations, speed testing, and finally, a chassis model. To do the last one, we made a simple model in PTC Creo.

    Bigwheel Presentation

    Bigwheel Presentation By Arjun and Karina

    Task: Present about Garchomp

    As a new freshman on Iron Reign, I took on the responsibility of a robot we called Bigwheel. Karina and I worked on getting the robot into something that could be put through load tests, meaning tightening the chain, fixing misaligned sprockets, and getting the wiring together. We participated in the Chassis Presentation workshop hosted by technicbots for teams all around the North Texas region to work on one or more chassis, perform various tests with them and then present their findings. We presented our chassis Bigwheel, which is driven by 2 large 8-inch wheels, with a pair of 2 free-spinning Omni wheels in the back. This can be seen in the presentation below:

    To create our chassis we used 2 8-inch wheels, each driven by 2 Neverrest 60 motors. There are also two free-spinning omni wheels in the back. The robot uses REV rails and plexiglass for it's main body.

    Our first test is the 5-second distance test. Our robot had a lot of torque due to the Neverrest 60 motors, so it moved slower than other robots, but was unaffected by the additional 30lbs weight.

    Our second test is the 3-second turn test. Again, some other robots could turn better faster than us. However, due to having no proper mechanism for restraining our weights, along with other mysterious problems such as battery disconnections that only happened during this test, we were unable to try this test with load, however we presume that due to the torque, the results should be similar to those without load. Our center of rotation is also off due to only the front two wheels being powered. As such, the back of the robot makes a wide arc as it turns.

    Our next few test results are unremarkable.

    Our robot had a lot of sideways drift, mostly due to bad build quality. If we intend to use it during the season, we will try to fix this.

    Overall, our chassis performed well under load, but could use a little speed boost. If we want to further develop it, we plan to use Neverrest 20s with more torque on our external gear ratio, so we can get more speed out of it.

    Garchomp Presentation

    Garchomp Presentation By Janavi and Kenna

    Task: Present in the Inviational Presentation Series

    Today, we participated in the Chassis Presentation workshop for teams all around the North Texas region; the project was to design robots and perform various tests with them, then present findings. We presented our chassis, Garchomp, a mechanum wheel chassis as can be seen in the slide photos below.

    Presentation

    To create our chassis we used 4 never rest 40 motors one for each wheel and the structure of the chassis was created by using tetrix rails. We connected the wheels to the motors by using a 1:1 gear ratio. While there are many benefits to using a gear ratio for your wheels be forewarned that if your wheels are not perfectly aligned attaching your chains to mechanum wheels will become a living nightmare as can be seen in our previous posts.

    One of the reasons that attaching the chains was so difficult for us was because we discovered that because we had used wooden sides instead of the aluminum sides that Kraken used our wheels became misaligned to the two different types of wood used for the sides.

    While our robot is not able to do a 360 degree turn as fast as some other robots presented today it is able to hold a considerable amount of speed while moving at a constant speed.

    Since this chassis was designed for last years competition it is able to consistently drive onto the balancing stone

    Rover Ruckus Brainstorming & Initial Thoughts

    Rover Ruckus Brainstorming & Initial Thoughts By Ethan, Charlotte, Kenna, Evan, Abhi, Arjun, Karina, and Justin

    Task: Come up with ideas for the 2018-19 season

    So, today was the first meeting in the Rover Ruckus season! On top of that, we had our first round of new recruits (20!). So, it was an extremely hectic session, but we came up with a lot of new ideas.

    Building

    • A One-way Intake System

    • This suggestion uses a plastic flap to "trap" game elements inside it, similar to the lid of a soda cup. You can put marbles through the straw-hole, but you can't easily get them back out.
    • Crater Bracing
    • In the past, we've had center-of-balance issues with our robot. To counteract this, we plan to attach shaped braces to our robot such that it can hold on to the walls and not tip over.
    • Extendable Arm + Silicone Grip

    • This one is simple - a linear slide arm attached to a motor so that it can pick up game elements and rotate. We fear, however, that many teams will adopt this strategy, so we probably won't do it. One unique part of our design would be the silicone grips, so that the "claws" can firmly grasp the silver and gold.
    • Binder-ring Hanger

    • When we did Res-Q, we dropped our robot more times than we'd like to admit. To prevent that, we're designing an interlocking mechanism that the robot can use to hang. It'll have an indent and a corresponding recess that resists lateral force by nature of the indent, but can be opened easily.
    • Passive Intake
    • Inspired by a few FRC Stronghold intake systems, we designed a passive intake. Attached to a weak spring, it would have the ability to move over game elements before falling back down to capture them. The benefit of this design is that we wouldn't have to use an extra motor for intake, but we risk controlling more than two elements at the same time.
    • Mechanum
    • Mechanum is our Ol' Faithful. We've used it for the past three years, so we're loath to abandon it for this year. It's still a good idea for this year, but strafing isn't as important, and we may need to emphasize speed instead. Plus, we're not exactly sure how to get over the crater walls with Mechanum.
    • Tape Measure
    • In Res-Q, we used a tape-measure system to pull our robot up, and we believe that we could do the same again this year. One issue is that our tape measure system is ridiculously heavy (~5 lbs) and with the new weight limits, this may not be ideal.
    • Mining
    • We're currently thinking of a "mining mechanism" that can score two glyphs at a time extremely quickly in exchange for not being able to climb. It'll involve a conveyor belt and a set of linear slides such that the objects in the crater can automatically be transferred to either the low-scoring zone or the higher one.

    Journal

    This year, we may switch to weekly summaries instead of meeting logs so that our journal is more reasonable for judges to read. In particular, we were inspired by team Nonstandard Deviation, which has an amazing engineering journal that we recommend the readers to check out.

    Programming

    Luckily, this year seems to have a more-easily programmed autonomous. We're working on some autonomous diagrams that we'll release in the next couple weeks. Aside from that, we have such a developed code base that we don't really need to update it any further.

    Next Steps

    We're going to prototype these ideas in the coming weeks and develop our thoughts more thoroughly.

    Testing Intakes

    Testing Intakes By Ethan and Evan

    Task: Design a prototype intake system

    In our first practice, we brainstormed some intake and other robot ideas. To begin testing, we created a simple prototype of a one-way intake system. First, we attached two rubber bands to a length of wide PVC pipe. This worked pretty well, but the bands gave way a little too easily.

    For our next prototype, we attached a piece of cardboard with slits to a cup approximately the size of a cube or block. It operates similarly to a soda cup lid with a straw hole. An object can go in, but the corners of the hole spring back so that it can't escape.

    Next Steps

    We probably won't go with this design - we'd have issues separating the different kinds of game elements, and it may be too slow to feasibly use. But, its a first step and we'll see what happens.

    Choosing Drive Train

    Choosing Drive Train By Janavi

    Task: Analyze the game

    In our last post, we created a chart where we listed each task asked based on point value and the level of difficulty, separated by autonomous and teleop. Our goal is to find a drive train that will allow us to build a robot to accomplish all of these tasks efficiently and consistently, but this matrix will allow us to determine what to focus on first.

    Drivetrain Comparison

    This summer we created a variety of drivetrains for a summer chassis project hosted in coordination with other teams from the North Texas region. We have compiled a list of the drivetrains and the criteria we need to consider for Rover Ruckus.

    What do we need to look at in a Drivetrain?

    • Light
    • Sturdy
    • Easily Maneuverable
    • Fast
    • Low center of mass to avoid tipping
    • Reliability

    Comparison

    Eliminated? Reason for Elimination Pros Cons
    Miniature Mechanum Drive NO N/A
    • Omni-Directional
    • Fast turning
    • Easy to design
    • Experience with
    • Driving/Building
    • light
    Uneven power
    Big Wheel NO N/A Unique Design We have less experience
    Larger Mechanum Drive YES Need light robot; may use mini mechanum chassis instead Familiar Design Too heavy for this years competition
    Swerve YES Difficult design, Many motors and servos, we have less experience Easier to maintain at high speed Unfamiliar and difficult to design and maintain
    8-wheel Drive YES Many wheels, Difficult of maneuver, no omni directional movement 100% power forward Difficult to maneuver
    Holonomic Drive YES Less push power in all directions; hard to integrate into robot Easy to turn and maneuver Hard to design; hard to integrate into base; Only 50% power in all directions

    Selecting Wheels

    Selecting Wheels By Janavi

    Objective: Determine the type of wheel that best suits the chassis

    In the Choosing Drive Train E-16 we decided that we will use the chassis BigWheel. We know that our wheels need to be light weight but we need to determine the size of the wheel that will keep our robot far away enough from the ground for us to provide enough clearance to allow us to climb over the crater rim. But, if we choose wheels with a large radius we risk raising the center of mass.

    Pros Cons
    Ironton 12in. Solid Rubber Spoked Poly Wheel
    • light
    • durable
    • Large Turns
    • Extremely Large
    Ironton 16in. Solid Rubber Spoked Poly Wheel
    • light
    • durable
    • Raise center of mass
    • Extremely Large
    • To prevent tipping we now have a much shorter distance to correct imbalance
    Ironton 8in. Solid Rubber Spoked Poly Wheel
    • light
    • durable
    • Not large enough to significantly move the center of mass

    Brainstorming Two

    Brainstorming Two By Evan, Abhi, and Janavi

    Task: Have a 2nd brainstorming session

    We had another brainstorming session today, which allowed us to break down into some new building tasks.

    Intake System 3 - TSA Bag Scanner

    This part of our robot is inspired by the bag-scanning machine in TSA lines, more specifically the part at the end with the spinning tubes. The basic design would be like a section of that track that flips over the top of the robot into the crater to intake field elements.

    Intake System 4 - Big Clamp

    This one is self-explanatory. Its a clamp, that when forced over a block or a cube, picks it up. It's not that accurate, but it's a good practice idea.

    Lift 2 - Thruster

    We want to make lifting our robot easy, and we're thinking of a slightly different way to do it. For our new lift idea, we're installing a vertical linear slide that forces the robot upwards so that we can reach the lander.

    Next Steps

    We're working on building these prototypes, and will create blog posts in the future detailing them.

    Chassis Brainstorming

    Chassis Brainstorming By Ethan and Evan

    Task: Brainstorm chassis designs

    At the moment, we've used the same chassis base for three years, a basic mechanum base with large wheels. However, we don't really want to do the same this year. At the time, it was impressive, and not many teams used mechanum wheels, but now, its a little overdone.

    Thus, we have BigWheel. We used this as a practice design, but we ended up really liking it. It starts off with two large rubber wheels, approx. eight inches in diameter, mounted at the back and sides of the robot. Then, we have two geared-up motors attached to the motors for extra torque and power. In the front, we have a single omniwheel that allows our robot to turn well.

    Proposed Additions

    First, we need to add an intake system. For this, we're considering a tension-loaded carwash that can spring out over the crater wall. It'll pull elements in and sort them through our intake using our separator, which we will detail in a later post. Then, the robot will drive over to the lander and lift itself up. Since the main segment of the robot is based off of two wheels, we're attaching a telescoping slide that pushes off of the ground at the opposite end and pivots the front of the robot upwards. Then, the intake will launch upwards, depositing the elements in the launcher.

    Next Steps

    We need to create a proof-of-concept for this idea, and we'd like to create a 3D model before we go further.

    Hanging Hook Prototype

    Hanging Hook Prototype By Abhi, Ethan, Justin, and Janavi

    Task: Design a hook for pulling the robot on the lander

    To get a head-start on latching and delatching from the lander during autonomous, we got a head start and made some hook prototypes. If your robot can just do these two things, you can score 80 points. When making this hook, it needs to be modular enough to not require much accuracy but also needs to be strong enough to hold 42 pounds. This hook works just that way.

    We designed this hook to have a slanted top to glide the robot into position if we aren't in the right place, making it very modular. In addition, we 3D printed this hook with ~80% infill in nylon after designing in PTC Creo. First, we tested it by hanging ~20 lbs of material off of it for one minute. This worked, but a little too well. While the nylon piece remained undamaged, the metal bracket it was supported by bent at a ninety degree angle. So, we had to pursue further testing.

    For our next test, we plan to hang a mass outside for a week. Dallas weather has been extreme lately, with a lot of rain, humidity, and heat. This will be the ultimate stress test; if one of our pieces can survive the outdoors, it can survive just about anything.

    Next Steps

    We're probably going to have to reprint this to be a bit more fitting for our robot, but its a good start and it works great so far.

    BigWheel Chassis

    BigWheel Chassis By Evan

    Task: Work on a possible chassis

    We've been toying around with the idea of using BigWheel, our Summer Chassis Research Project bot, in this year's competition with a few modifications. The idea for this robot is that it has a collection system that extends into the crater, and folds up on top of the robot. It reaches in with the collection arm, and grabs the blocks/glyphs, drives backwards and flips vertically using the drive wheels as a point of rotation. Here’s a basic sketch of what that looks like.

    The way this will be achieved is with a spring loaded lever connected to the omni wheel that makes up the holy trinity of wheels. So far I have pieced together the arm that reaches into the pit, which is powered by two NeverRest 60s and geared in a two to one ratio to significantly increase the torque. Between the two arm I plan for a horizontal beater bar to intake blocks and a slide attached to a servo to separate blocks and balls based on their size. The idea is to have a way of sorting based off of the physical shape rather than by digital sensing means. The more that can be done purely off the shape of the elements, the better.

    Next Steps

    Next week, the team will have to make some serious progress since there will be more hands to build. My hope is that the lever will come about soon, even if in its most infant stage, and that some semblance of a functioning robot can be game tested in the next few weeks, just in time for a scrimmage and potentially an early qualifier.

    Intake Sorter

    Intake Sorter By Abhi

    Task: Design a sorter for the balls and blocks

    To increase the efficiency of our robot, we looked into ways to passively sort minerals during intake and deposit. It is important to sort because it requires less precision under driver control allowing a faster and more efficient robot. Though bulky, we designed an initial design to sort the minerals.

    When this piece is mounted and both blocks and balls are run over it, the balls run down the top and don't fall in the collector, but the blocks fall in the holes. We modeled this design in PTC Creo, then printed it in ABS.

    Next Steps

    This design works but is large so we're going to have to find a smaller and simpler way to sort game pieces. In the future, we're going to minimize this and probably move to a smaller sorting mechanism.

    Designing Wheel Mounts

    Designing Wheel Mounts By Justin

    Task: Create wheel mounts for our Mini-Mecanum chassis

    Today, we modeled two possible designs for mini-mecanum wheel mounts. The purpose of the mounts is to hold a churro or hex shaft in place to mount mecanum wheels to. The first design was a 6cm by 6cm square with rounded edges that was 5mm thick. A hexagon was removed from the center to hold the churro that supports the mecanum wheel. This design, when printed on low infill, allowed the churro to rotate when enough force was applied. We modeled this design off of the wheel mounts on Kraken and Garchomp; the only differences are the size and material. Because we will be 3D printing these mounts, material efficiency is very important. This mount design used a lot of material to make a prototype, meaning a finished stable mount would need even more material to prevent the churro or hex shaft from slipping.

    Taking these problems into account, we designed a different way to mount the wheels. The new version can mount underneath a REV Rail and hold the shaft or churro perpendicular to the rail. This design uses much less infill than the previous one because of how small the mount is, and because the REV Rail also acts as support to prevent the churro or shaft from spinning. The mount also allows the mini-mecanum wheels to be mounted as close to the frame as possible, which can help make the robot more compact. This design will allow us to easily mount mini-mecanums to our frame, while using minimal filament and taking up very little space.


    Next Steps

    We need to build the full mini-mecanum robot to judge whether these designs will fully work.

    Designing the Corn Cob Aligner

    Designing the Corn Cob Aligner By Ethan and Abhi

    Task: Design an aligner for the beater bar intake

    The ice cube tray is 9 holes wide and each hole is 16.50mm wide and long. Using these measurements, we created an aligner that would cause the ice cube tray to roll into a cylinder.

    We're designing an intake that will allow the robot to intake particles, and this is a major portion. This will allow us to increase the amount of friction put on the particles, allowing for a more secure grip.

    However, this system has issues. First, we wanted the edges to still be mildly compliant, and this wheel filled out the edge rows to full depth, making them a little too tough. Plus, they made the silicone height too variable, so that we couldn't solely pick up the balls. So, we designed a second aligner with shorter spokes so that the edges would be fully compliant while still being held securely.

    Next Steps

    We need to finish up the corn-cob beater bar, but after that we'll be able to start testing.

    Corn-Cob Intake

    Corn-Cob Intake By Ethan and Abhi

    Task: Design an intake system unique for balls

    Right now, we're working on a static-deposit system. The first part of this system is having an intake mechanism that passively differentiates the balls and cubes, reducing complexity of other parts of the design. Thus, we created the corn-cob intake.

    First, we bought ice-cube trays. We wanted a compliant material that would grip the particles and be able to send them into a larger delivery mechanism.

    Then, we designed a wheel which' spokes would fit into the holes on an ice cube tray, allowing the tray to stay static while still being compliant in a cylindrical shape. Then, we can put axle hubs through the center of the wheel, allowing us to mount the wheels on a hexagonal shaft. Then, we can mount a sprocket on that, allowing the bar to be rotated for intake. This bar is mounted at the height of the balls, not blocks, so we can passively sort the minerals in-action.

    Next Steps

    We need to mount this on our robot and design a way to deliver the field elements. We're also going to go into more detail on the ice cube mounts in a later blog post.

    Team Marker Fun

    Team Marker Fun By Karina

    Task: Create the Team Marker

    Last week, we decided to take up the task of creating the team marker, a simple project that would surely be overlooked, but can score a significant amount of points. We wanted the marker to be meaningful to the Iron Reign, but also follow the team marker rules. To start, we made a list of ideas:

    Last season, Ducky (as seen in idea #4) brought Iron Reign good luck whenever the drivers squeezed them, and so we knew that we wanted to incorporate Ducky into whatever the final product would be. Some team members suggested fusing together multiple rubber duckies to fit the dimensions in the rule book. I had a better idea. I thought, "Why not put Ducky in a box?" However, trapping Ducky in a box would prevent us from ever squishing Ducky again (as long as they are trapped in the box). But then an even better idea came up: "Why not put Ducky in a cage?" And so we got to work making a cage for Ducky, one that we could release them from or reach in to whenever we need a squish for good luck.

    We cut two pieces of 3.5 inch x 3.5 inch polycarb to serve as the ceiling and floor of the cage. Then we used 8 standoffs, in pairs of two at each corner of the cage, to serve as the bars. To not waste anymore standoffs, we used zipties as the cage bars. Additionally, the flexibility of the zipties allow us to squeeze Ducky out of the cage from in between the bars. In the end, Ducky looked like the most happy prisoner we've ever seen:

    Next Steps

    With the team marker built, we need to test how well it does its job (staying in one piece for the duration of a match hopefully). It's survived many nights now in the our coach's house, which is no small feat, with all the children running about and constantly misplacing things. Once we have an intake system working for the minerals, we will need to test how compatible it is with Ducky in a Cage. Lastly, we need to decorate Ducky's cage, including our team's number (6832).

    Another Design Bites the Dust

    Another Design Bites the Dust By Ethan

    Task: Discuss a new rule change

    At one point, we were thinking about creating a "mining facility" robot that stays static within the crater and delivers the blocks into the mining depot. In our eyes, it was legal as it would hold as many blocks as possible inside the crater but only deliver two at a time outside. It would be super-efficient as we would be able to stay within the crater, and not need to move.

    However, fate has struck. Earlier this week, we received this message:

    The rule limiting control/possession limits of minerals has been updated to indicate that robots may _temporarily_ hold more than 2 minerals in the crater, but must shed any excess over prior to performing any other gameplay activities (which would include scoring).
    says that "Robots In a Crater are not eligible to Score Minerals". Per the definitions of "In" and "Crater", if _any_ portion of a Robot is in the vertical area above the crater (extending from the field walls to the outside edge of the Crater Rim), then scoring a Mineral results in a Major Penalty.
    says that Robots may not obstruct another Robot's path of travel in the area between the Lander and a Crater for more than 5 seconds.

    This means that we couldn't do a static mining facility as we cannot score within the crater. Since we'd have a portion of the robot always in the crater, the existence of our robot would be a major penalty.

    Next Steps

    So, we need to rethink our robot. We still want to create a semi-static robot, but we need to redesign the intake portion.

    Mining Base 2.0

    Mining Base 2.0 By Ethan

    Task: Rethink our static robot idea

    So, our dream this year is to create a static robot. Last week, we found out about a rule change that would prevent our mining robot from staying within the crater. Naturally, we found a way around this, leading us to the Mining Base 2.0.

    The robot will be fixed under the lander's hooks, and have a horizontal and vertical linear slide attached to it. The horizontal linear slide would reach over the crater walls and pick up the silver balls, and shoot them up towards the lander. On the lander, our vertical linear slide would create a backboard that would allow the balls to fall into the lander. This wouldn't violate the rules as we wouldn't be in the crater. And, it would give us the benefit of having an extremely high-scoring robot.

    Next Steps

    We need to start on the designs of this robot, but to do this, we first need to create a working chassis.

    BigWheel+

    BigWheel+ By Evan

    Task: Continue work on BigWheel

    BigWheel has gone through a few major changes. First and foremost, it now has a flipper arm, AKA Superman. Since the robot itself is the lift mechanism, we had to put a lot of work into Superman's design. Right now it is a 10 inch REV rail attached to two 125-tooth gears for redundancy, with a custom 3D printed mount housing an pair of omniwheels on the other end. On the motors, we have two 15-tooth gears, resulting in a 3:25 gear ratio. This gives us a ridiculous amount of torque that lifts the robot up smoothly. On top of the flipper, we’ve added extra supports on the arm mounts, as when we went to the Hendricks scrimmage, we found that the two sides were out of alignment, and one was bending more forward than the other, making the arm bend unevenly to one side and throwing the whole robot out of alignment.

    The next step is to strengthen the arm itself, as the two sides have a tendency to want to do their own things, mainly the side with the intake motor mounted to it. Since the supports have been put in though, Bigwheel has been functioning much better, and the arm no longer flops to one side. General wire management has also taken place, as we'd dealt with wires getting stuck in the gears.

    Next Steps

    Bigwheel was built on a bit of a shabby base, mostly being made of a piece of polycarb and some aluminum bars, and not giving much in terms of change. We’ve cut here and there, drilled a few holes, unattached and re-attached a couple of things, but in all it’s a very stiff robot, and doesn’t lend itself to fluidity of design. That’s why we plan on making a second version of this base, hopefully with thinner polycarb and more secure sides that have been welded together but can be removed more easily. The exact design is still being modeled, but we have a direction to jump off from, and I believe we can make that leap to a better robot.

    Mini Mecanum Chassis

    Mini Mecanum Chassis By Janavi and Justin

    Task:

    Over the summer, we designed many robots for the North Texas Chassis Project, including one based off of last year's Worlds robot, Kraken. The robot chassis had 6" mechanums. But, based on what we know about this years challenge we have decided that this chassis does not utilize the 18-inch cube effectively.

    We have chosen to design a chassis that is similar in function to Kraken, but smaller in size with 4" mecanum wheels.

    Our plan is to design a low-lying 6" x 6" robot, a marked difference from the usual 18". However, this new design means that many of our 3D printed parts are unusable on this robot; for example, our former wheel mounts are much too large for the new robot and wheels, as well as their corresponding axles.

    These bearings are hexagonal, requiring a new wheel mount design.

    Justin first designed the axle plate below to solve this, but it raised the robot off the ground quite a bit, risking debris becoming stuck under the bot. As well, it was flimsy - it was mounted too far from the robot. We went back to the drawing board and brainstormed various methods we could use to attach the axle the frame in a more secure way; we found that we use a pillow block design would save space, while also having a lower-lying robot. This design worked out beautifully, leading to the design we are currently using.

    The axles and wheels aren’t the only new thing about our robot: we've switched to NeverRest 20s in lieu of our normal 40s and 60s. This is another reason that we wanted to create such a minute robot. The gear ratio combined with the size will make this robot a speed demon on the field and allows us to dart between the minerals and the depositing location quickly.

    Next Steps

    In the upcoming weeks we will continue to tinker with this chassis design by adding a linear side and our gathering mechanism, and hopefully, we will be able to demonstrate it at the scrimmage next week.

    Intake Update

    Intake Update By Ethan, Abhi, Justin, and Kenna

    Task: Update the intake for the new robot size

    We created the corn-cob intake a few weeks ago. Unfortunately, it was a little too big for the Minichassis, so we had to downsize. So, we designed Intake Two. Continuing our history of using kitchen materials to create robot parts, we attached two silicone oven mitts to a beater bar equipped with Iron Reign's REVolution system. Then, we attached a REV Core Hex Motor to the design, then added a 2:1 gear ratio to increase the speed, as the motor wasn't exactly what we wanted.

    Then, we attached our new passive sorting system. Instead of being the old, bulky sorting system, the new system is just three side-by-side bars spaces 68mm apart with tilted wings to move blocks upwards. The 68mm number is important - the size of a gold block. This allows the balls to be struck and fly upwards into the intake while sliding the blocks through the system.

    Next Steps

    We need to attach this to the robot to test intake. The most likely way this'll be done is through a pivot over the walls of the crater from the top of the robot.

    BigWheel Arm

    BigWheel Arm By Evan

    Task: Design an arm for BigWheel

    Bigwheel’s intake arm is one of the most important parts of the robot. Since our scrimmage, we have learned how to make this arm much more efficient, starting with some supports. The original intake arm was made of two scrap Tetrix rails. The result of this was that the two sides of the arm would be out of sync, creating a twist in the arm that caused it to move oddly. Thus, it has been stabilized with cross beam REV rails.

    The next upgrade on the arm is going to be the box to hold the minerals. Right now it’s just a cardboard prototype and we need to move to the next version. After a bit of debate, we decided to craft it out of polycarb. The reason polycarb was not our immediate solution is because it’s unfortunately quite heavy, and instead the first thing we came to think of was thin plywood and duct tape. Thin slices of plywood would be taped together to create a fabric like box that still had form. This idea still lent itself to breakage, and we next went to a design using a thin plastic sheet, the same kind of plastic that is used inside milk cartons. The only issue is that it’s super weak and doesn’t form well, so we would have to build a frame for it, much like the plywood and tape.

    Next Steps

    Right now we’re toying around with the idea of an arm that not only flips out but also extends using a gear and tooth track made from Tetrix parts of days gone by. The reason for this is to gain a little extra height that we were lacking before in the robot and a little more flexibility when we grab minerals from the crater. To do this I had to take apart the arm from our first ever FTC robot, and use the toothed track and gear plus the extra long tetrix bars to create the slides. So far the slides are surprisingly smooth and we have high hopes for the future of the arm.

    Torque Calculations

    Torque Calculations By Karina

    Task: Calculate the torque needed to lift chassis

    After seeing how well the robots that could latch onto the lander performed at the scrimmage, Iron Reign knew that we had to be able to score these points. We originally tried lifting with a linear slide system on MiniMech, but it was not strong or sturdy enough for the small chassis, and would definitely not be a functional system on BigWheel in time for competition. And so we thought why not use this opportunity to *flex* on the other teams with an alternative design? An idea was born.

    We decided we would latch onto the lander using the same arm used for intake, and then pivot the main body of BigWheel up off of the ground about an "elbow joint", much like how humans do bicep curls. To do so, our motors would need to have enough torque to be able to lift the loaded chassis off the ground once the arm hooked onto the latch. First, we measured the mass of BigWheel. Then we found where the center of mass was located. The distance from the pivot point to the center of mass became our lever arm, also known as the radius.

    Calculating torque required knowing the forces acting on BigWheel at its center of mass. In this case, there was only the force due to gravity (F = mg). Before we could plug BigWheel's mass into the equation, we converted to units of kilograms (kg), and then used the value to find the newtons of force that would oppose the upward motion:

    Finally, we plugged the force and radius into the torque equation:

    Next Steps

    The next step is to test which gear train will output this torque value based on the motors used and the gear ratio.

    Linear Slide Lift

    Linear Slide Lift By Janavi

    Task: Design a lift for MiniChassis

    For extension both into the crater and lifting our robot up to the crater we have decided test a linear slide system. We plan to utilize linear slide system for both vertical and horizontal extension on MiniMech.

    Horizontal Extension Goals

    • Long Enough to reach Crater from distance
    • We need to determine how many stages we need

    Vertical Extension Goals

    • Long Enough to reach lander
    • Strong enough to support robot weight

    When designing a lift we need to determine the optimal gear ratio to allow our lift system to lift the robot but still do it relatively fast. Realistically looking at the aluminum parts we are using we plan for the robot to be around 35 lbs. We also know that the lander is 22 inches above the ground and we plan for the linear slide to extend to 14 inches off the ground This would mean that the point of rotation for our hook mechanism would be 22 inches - 14 inches = 7 inches below the latch on the lander.

    We plan to use REV 40:1 motors that have 594.7 oz*in. Now using these calculations we can determine our needed gear ratio.

    This gear ratio of 6.6 means that for our robot we need a motor to gear ratio that needs around seven rotations of the motor to provide one rotation of the hook.

    We knew the max weight of the robot would be around 20 pounds since the total weight of all the parts in the kit is less than 20 pounds. The point of rotation for the hook would be around 5.5 inches below the lander latch. This is because the bottom of the hook is around 22 inches above the ground and the point of rotation will be around 16.5 inches off the ground so that we can account for space for a gear while staying within the 18 inch box. Below is the torque calculation.

    Next Steps

    BigWheel Upgrades

    BigWheel Upgrades By Evan

    Task: Get BigWheel ready for the tournament

    Today, we built mounts to attach both types of intake to the rack; the rack-and-pinion corncob intake and the red-flapped intake. We also created a new way of mounting the arm to the chassis. The idea is that since it’s attached to the rack and pinion track, it reaches high enough for the robot to put the minerals in the lander. We made the arm with a 12-86 gear ratio. Our next plan is to create the mount, minimizing the size of the arm.

    The final addition is a tail for the robot to be able to stop itself from flipping backwards, something that is a very real danger of the design. It will probably be made of polycarb with aluminum or steel support on either side, just in case the polycarb is not enough to support the push of the robot. Part of this process will involve some code tuning so that the robot stops itself, but the tail is necessary as a preventative measure.

    Next Steps

    There’s still a lot of stuff we will have to do to prepare the robot physically for the competition this Saturday, but I believe it will get done.

    Materials Testing Planning

    Materials Testing Planning By Ethan

    Task: Design a lab to test nylon properties

    So, Iron Reign is used to using off-the-shelf materials on our robot: silicone oven gloves, ice cube trays, nylon 3D-printed parts, and more. But, we've never actually done a thorough investigation on the durability and efficacy of these parts. Because of this, we've had some high-profile failures: our silicone blocks breaking on contact with beacons in RES-Q, our nylon sprockets wearing down in Relic Recovery, our gears grinding down in Rover Ruckus. So, we're going to do an investigation of various materials to find their on-robot properties.

    Nylon Testing

    A majority of the 3D-printed parts on BigWheel are nylon - we find it to be stronger than any other material save ABS, but much less prone to shattering. Still, we still deal with a substantial amount of wear, and we want to find the conditions under which damage happens.

    So, to start, we are printing a 4.5" x 1.5" block with a thickness of 4mm with an infill of 60% out of nylon. We chose these values as our average part is about 4mm thick, and our high-strength nylon pieces are about 60% infill. Then, we are going to test it under a variety on conditions meant to simulate stressful operation. As well, we're going to measure other values such as coefficient of friction using angle calculations.

    Silicone Testing

    Similarly, we use the silicone oven mitts on our intake; we find that they grip the particles pretty well. The main thing that we want to test is the amount of energy they have while rotating and then the amount of energy they lose upon collision. We plan to test this through video-analysis. In addition, we wish to test the coefficient of friction of the mitts to see if a better material can be found.

    Next Steps

    We are going to perform these labs so that we can compare the constants we receive to commonly accepted constants to test our accuracy.

    Chassis Mark Two Planning

    Chassis Mark Two Planning By Ethan

    Task: Plan a new BigWheel chassis

    Our next tournament is a while away, in about two months. So, we have a little bit of time to redesign. And, our current chassis has plenty of faults.

    Our original BigWheel base.

    First and foremost, our chassis was built for a testing competition, not to be a full fledged competition robot. As such, it's a little lacking in features that would be normal on such a robot such as mounting points for other components, durability, and free space. So, we need a redesign that allows for greater modularity and functionality.

    We're starting from the ground up; our current base is a square metal frame with a polycarb bottom. While this is a good start, it has some issues: the base seems to be a little wobbly due to the polycarb, there's only one level of construction, so our motor mounts, REV hubs, and supports compete for space, and we have to add all the counting points ourselves.

    The main way to prevent the wobbliness is by replacing the polycarb with something sturdier, as well as not having everything simply bolted together. Thus, we're going to dive headfirst into the next step - welding. We plan to cut a base out of aluminum as well as four side plates to create a dish-like shape. Then, we plan to TIG weld these plates together (TIG welding uses a tungsten electrode in contact with two separate metal plates in combination with a filler metal that melts and joins the two plates together).

    Basic design for the newest version of BigWheel.

    Next Steps

    We plan to cut the aluminium next week, and TIG weld the pieces together the week after that. We're beginning to train a few of our members on TIG welding and we already have some of the safety equipment to do so.

    Friction Coefficient and Energy

    Friction Coefficient and Energy By Ethan

    Task: Measure the coefficient of friction of our oven mitt intake

    We want to measure various constants of materials on our robot. Earlier this season, we found that a nylon-mitt collision on our intake sapped the rotational energy of our intake. But, that was just a build error, easily fixable. But now, we plan to measure the energy lost from particle-mitt collisions, and the first part of this is to find the coefficient of friction of the silicone mitts.

    To measure the coefficient of friction, we first had to simplify an equation to determine what values to measure.

    From these calculations, we determined that the only factor to measure to determine the coefficient of friction between blocks and the mitts is the angle of incline. Therefore, we created a simple device to measure the angle at which slippage begins to occur.

    The angle was about 27 degrees, so the coefficient of friction is equal to arctan(27)=0.44. This is a pretty good coefficient of friction, meaning that the intake is very efficient in bringing the particles in, but it also means that the intake loses more energy on collision.

    Next Steps

    We need to measure further constants such as stretch and wear of nylon. To do so, we're printing a simple testing nylon block.

    Selecting Lift System

    Selecting Lift System By Janavi

    Objective: Determine the type of lift system will allow us to delatch and reach the lander

    In our past post Choosing Drive Train we decided that we will use the chassis BigWheel. After deciding the base we need to now think about the lift system that we want to use to allow us to both deposit into the lander and latch onto it. Evan and I have been experimenting with linear slides to use for our lift. I have been working on a REV linear slide lift system as referenced in the post "Linear Slide Lift". Evan has been working on a separate ball bearing linear slide. As well as these two options we are looking into past linear slides and ones that we have seen teams use in past challenges. We need to determine which of the linear slides works best based on the game requirements this season

    Linear slides needs according to game
    • Lift and lower robot from latch on lander
    • Extend out to Crater from distance to collect minerals
    • Extend out vertically to lander to deposit minerals

    What we want our linear slide to have
    • Light Weight
    • Bidirectional (Able to collect from crater and deposit)
    • Speed
    • Sturdy
    • Easy to fix and maintain in case of emergency
    • Small in size
    • Extend out to around 5 ft in height

    Linear Slide Options
    • Ball Bearing Lift
      • Heavy
      • Smooth
      • Reliable
      • Never used the before
    • Drawer Slides
      • Heavy
      • Low cost
      • Unwieldy
      • Familiar as we used them last year
    • REV Linear Slides
      • Light Weight
      • Not very reliable
      • Familiar

    Next Steps

    We need to select the best linear lift system for our chassis based on the requirements we set above.

    Linear Nylon Strength Test

    Linear Nylon Strength Test By Ethan

    Task: Measure linear nylon wear

    We've had some issues with our nylon sprockets, mainly through excessive wear and tear. So, we want to test what circumstances cause what deformation.

    Linear Deformation

    This one was simple. We printed this block with 60% infill (the highest infill we tend to use), measured its length (3.75") and hung one end from our deck. On the other end, we inserted a bar and attached 180 lbs of mass to it, then we measured its new length (3.8"). Thus, the constant of deformation is [weight]/[change in length] = 650 kg/cm. This demonstrates that linear transformation isn't Iron Reign's issue, as the highest possible weight put on any nylon piece on our robot is ~27 lbs/12.25kg.

    However, there is other damage. After testing, we found internal damage in the nylon from where it was hanging.

    Next Steps

    Next, we need to test the rotational damage that nylon incurs through friction. We plan to design a simple rotational sprocket and run it on a motor for a set amount of time and measure the wear to determine wear per unit time.

    Code Issues Break the Superman Arm

    Code Issues Break the Superman Arm By Abhi

    Task: Analyze the code issues that led to our robot breaking

    After constant use, our robot's Superman arm broke. At this point, it is important to analyze our failures. This error was not because of a build issue but rather a code and driver control issue.

    When testing, we always heard the gears grinding some times and we thought it wasn't an issue. There were instances like once when we accidentally made the robot stand up under a table. Other times, the robot would press the arm down into the foam and keep pushing when it couldn't really keep going, leading to grinding.

    Not only did the arm break but also the Superman mechanism. This broke mainly because we didn't set proper ranges of motion of the arm and the gears would grind when there was interference. Because of the damage, we can't use the existing gears.

    Next Steps

    We intend to gang up the gears and make the mesh stronger to fix the build side of things. In the code, I already added the software limits to motion so we don't have those problems anymore.

    Arm Repairs

    Arm Repairs By Evan and Abhi

    Task: Fix elbow and Superman

    This is a follow up to Post E-64, Code Issues Break the Superman Arm. We made some hustles and got them fixed. We reinforced Superman by ganging up multiple gears (as seen above) and repeated a similar process with the elbow arms. Hopefully this will make BigWheel more secure, especially with software limits in the code.

    Rotational Nylon Wear Test

    Rotational Nylon Wear Test By Ethan

    Task: Test the amount of wear on a moving nylon part over time

    After our last tournament, we noticed several 3D-printed sprockets that had worn down significantly. So, we wanted to measure how much wear one of our nylon sprockets takes per second.

    First, we printed out a model of one of the REV sprockets, using the STEP file here. We printed it with ~45% infill, our average for sprockets and other parts. Then, we attached a REV Core motor to an extrusion, then mounted the nylon sprocket on the other side. Then, we measured the length on one of the teeth. We ran the motor for 1:05:45, and then measured the length afterwards.

    So, the tooth length before was 5.3mm, and after, it was 5.23mm, for a difference of 0.07mm. Then, we ran the system for 1:05:45. This results in a wear rate of 1.77*10^5 mm/sec. So, given that we use our robot for about an hour, cumulatively, in a tournament, 0.0638mm, or 1.2% of the sprocket. This is enough to be noticeable under loose-chain conditions and indicates that we should keep extra sprockets at tournaments so that we can do a quick replacement if needed.

    Next Steps

    We plan to perform more materials testing in the future; in particular, we'd like to determine the wear rate of the regular REV sprockets as well, but this requires a more rigorous experiment.

    Selecting Intake System

    Selecting Intake System By Janavi

    Objective: Determine the type of intake system that will allow us to efficiently obtain and deposit minerals within the lander

    In our post "Selecting Lift System" we decided that the linear slide system that we will use is the MGN12H rails also referenced to as the Ball-Bearing slides. These slides while heavy provide the smoothest option. now that we have chosen the Lift system we need to determine the intake system that will allow us to take in two minerals and deposit them in the most efficient way possible. Throughout this season already we have been experimenting with different types of intake systems as seen in posts like "Pool noodle intake" and "Selective Intake" and "Scoring Mechanism"

    Intake System needs according to game
    • Collect only two minerals
    • Sort between silver and gold minerals

    What we want our linear slide to have
    • Light Weight
    • Speed of intake mechanism
    • Sturdy
    • Easy to fix and maintain in case of emergency
    • Small in size

    Passive Deposit vs Passive Intake

    Pros Cons
    Passive Deposit Faster intake Could be unreliable if not positioned correctly
    Passive Intake More accurate Harder to intake and therefore we score less

    Intake Mechanism Material / Shape

    Pros Cons
    Ice Cube Tray Compliant and smooth Not a far reach
    Surgical Tubing Farther reach Possibility of missing minerals due to sporadic behavior of surgical tubing
    Pot holder Brings in minerals Not far reach and too compliant
    Octopuckers ( from last year's season ) Experience with using material Too stiff and not far enough reach

    End of TIG Welding

    End of TIG Welding By Evan

    Task: Detail TIG welding plans and why they failed

    At the beginning of the season, we saw that our robot base was not as well crafted as we originally thought it to be. While we have worked to correct it over the season, it’s still not what we wish to see in a functional robot, and we came up with the idea of making the frame from light aluminum instead of the polycarb, and fix it with TIG welding.

    It seemed like a good idea at the time, but there were many other problems on the robot more important than a new base. So we pushed the TIG plan to the side, in lieu of correcting other issues like the lift and the intake. While we won’t completely throw the idea out, it will be a while before we begin to start the project. Also hindering us is the amperage output of the home, which is too low to run the TIG welder off of. Until we get additional amperage to the house, our plans will be on hold but not forgotten.

    BigWheel Arm Locks

    BigWheel Arm Locks By Evan

    Task: Create locks to keep BigWheel's intake arms in an extended position

    An important part of this year's challenge is scoring minerals in the lander. Additionally, our upright elbow cannot raise the scoring mechanism to the lip of the lander alone. Thus, we had to create a way to get those additional inches to score.

    First, we tried a REV linear slide design. This worked, but barely. It repeatedly got stuck, at one point even needing to be sawed apart at a tournament due to its inoperability. So, we switched to a new brand of linear slides, the MGN12H with 12mm steel rails. But, since we were no longer using REV, we needed a new design to keep the arms in the extended position.

    The new design relies on gravity. When the robot is on the lander in the hanging position, it will stay within the sizing cube. However, as it descends, the linear slides will glide upward, staying attached to the lander until the robot contacts the mat. And, as the slide finishes moving, it will move over a triangular piece of polycarb such that it is easy for the slide to move up, but near impossible to reverse its direction. This will ensure that the robot's arm stays extended.

    Next Steps

    We need to reattach the mounting point for hanging in order for this system to work.

    Scoring Mechanism

    Scoring Mechanism By Janavi and Abhi

    Task: Create a way to hold minerals

    We now have a lift and an intake system, but we're missing a way to hold onto and deposit the minerals after intake. To achieve this, we created a prototype.

    We wanted to create a box-like shape that can be attached to a moving axle to hold the minerals when lowered. When the lift is up in the air, the axle can rotate to lower the box and let the minerals fall into the depot. We tested out multiple designs but we ended up having to nix that as there was no way to get the minerals out of the box once they were in.

    Our second design was a sloped shape: just steep enough to hold onto the balls but not so steep that the balls couldn’t escape. To create this shape, we decided to have a rectangle attached to an axle able to hold the minerals when down and deposit the minerals when spun. We created multiple variations with different sizes as can be seen in the drawing below. We eventually settled on was design B, a square that was 155 cm by 155 cm.

    We decided to not use design A as it was simply too large and continuously hit against the edge of the rail. We progressed to a smaller size of 155 mm by 155 mm (design B) that worked well. We attempted another design of two separate backs as two separate channels for the minerals (Design C). However, we decided this wasn't a very good design because there was an increased chance of the ball getting stuck in between the channels, causing either a penalty or a decrease in the number of balls we can control.

    After creating the back of our holder, we realized that we needed to elevate it off the back of the rails at an angle. It was the only way to hold the balls and allow them to come down a ramp when the axle is spun. We decided that the best way to achieve this was through two wing-like triangles on the side that we could bend to ensure the minerals couldn’t escape out the side. We went through multiple designs as can be seen below

    At first, we attempted to attach two right angle triangles with 155mm acting as a leg of the triangle. We varied this design by increasing the angle of the slope so that the balls would be held at an angle that allows them to not slip. But, after creating this design out of cardboard and attaching it to the axle, we saw that the sharp angle interfered with the beater bar. To amend this, we changed the triangle attached to the end of the rectangle to have the 155 mm side be the hypotenuse of the triangle. Again, we varied the design in the steepness of the triangle. Through this, we determined that a slope of around 30 degrees was the best design.

    After finalizing our design, creating it out of cardboard, and attaching it to our robot, we cut the piece out of polycarb. We bent the side triangle using heat and drilled in the holes to attach the axle with.

    Next Steps

    Although this design works well, we want to continue to change and improve upon it. For example, the next way we can improve the design is by changing the way that the polycarb is attached to the axle through a 3-D printed attachment.

    Creating Side-Latches

    Creating Side-Latches By Evan

    Task: Allow the robot's arms to stand on their own

    The issue with the lift is that many of the pieces that need to be made require specificity that’s hard to obtain using aluminum parts, so we chose polycarb. The key to making these specialized parts is a small butane torch held at just the right distance. Run the torch back and forth across the part where you want to bend, in the pattern of the bend you’re trying to achieve, watching closely for the first air pocket. Once you’ve spotted it, bend it. For tight, right angle bends, press the piece of polycarb against a hard surface until the right angle is achieved. If there’s an issue in your bend, simply heat it up again. This, however, weakens the piece so try not to do it on pieces that need to bare a load. We had to bend a complex piece, and while, it doesn’t look super complex in the picture, it had very precise requirements so that everything could slide together in unison. The part we made went in between the two linear slides on the arms to the 3d printed latch we created, and worked very smoothly. While polycarb is not the best at retaining strength over distance, it’s worked well in this instance.

    Next Steps:

    The next stage for this will be to make these brackets out of steel once we have access to the forge. This will result in a new, stronger version, which will hopefully eliminate a potential point of failure in our current robot.

    Modeling Slide Barriers

    Modeling Slide Barriers By Kenna

    Task: Create barriers to prevent the linear slide from falling

    Recently, we added polycarb barriers to our linear slide system. They were created as a temporary measure by bending the polycarb with a blow torch and are less exact than we would like.

    I originally tried to overlap 3 rectangles, and Creo didn't register it as an enclosed shape and wouldn't extrude. For any geometric shapes you want to extrude, constructed lines in sketch mode make it much easier. They ensure that everything is perpendicular, but also that your shape will still enclose so you can extrude it. Armed with constructed lines, Our models printed in roughly 30 minutes using nylon on a Taz printer.

    Next Steps

    Though nylon has its many uses, it's still not as strong as polycarb. We're looking into whether or not the printed version will withstand the slide system. Perhaps, we may need to pursue a different material or a more exact method of creating polycarb barriers. Any posts continuing this thread will be linked here.

    Latch Model

    Latch Model By Abhi and Justin

    Task: Model and print the Latch

    Early in the season, we made a hook, Although it was durable, it required a higher amount of precision than we would have liked to have, especially in the rushed last seconds of the endgame. As a result, we designed a latch that is completely 3D printed and placed it on the robot.

    This is the general model of it fit together (excluding left panel). The panels in the front are there to guide the latch into place when extending upwards from the ground.

    This wheel represents what actually does the latching. When sliding upwards, there are two wheels that twirl in opposite directions and slot into the lander bracket. We attached a smaller piece to this to tension with a rubber band allowing us to move up into the bracket but not back down.

    Next Steps

    We actually mounted this onto the robot and it seems to hold its own weight. However, the mounting was done very weirdly so we need to find a definite place for this system before we use it in auto or end game.

    Belt Drive

    Belt Drive By Evan and Karina

    Task: Install a belt lift on our robot for depositing

    The most recent addition to BigWheel has been the addition of a belt drive lift on either side of the linear slides. We chose a belt lift over a string and pulley lift because it is a much more secure, closed system, and doesn’t require stringing. For these reasons, we switched to belt drive. While more complicated to build, it requires no spool, only tension, no knots, and is super smooth in its motion. Our current design relies on the same time of belt drive used on 3D printers, something that we as a team are familiar with. The issues that come with using a belt drive lift include a more complicated setup and a more difficult time to repair in the pit, a lower ability to bear weight due to slippage of the teeth, and difficulties in tensioning.

    Next Steps

    So far the belt drive has experienced a bit of slippage, but with the intake redesign we are just about to start on, it should have a better time lifting the intake.

    Designing Side Shields

    Designing Side Shields By Ethan

    Task: Create side shields for BigWheel

    Iron Reign has access to an Epilog Mini laser-cutter through our school, so we decided to use it to create side shields to protect our robot during defensive play, display our team numbers, and prevent wire entanglement

    We created our original design in Illustrator. The canvas size was 12"x18", ensuring that our design stayed within the size limits. Then, we found the side height of our robot's wheel hubs (1.3") for later use. The original design, above, was inspired by 1960s teardrop campers.

    The Epilog Mini is a CO2 laser cutter, which means that it can cut acrylic, cardboard, and wood. We don't keep our robot at school, which meant that we had to make a test cut at school. We had a variety of issues, our first print cut way too small, about 8.5"x11" when it should've been 17"x8". Our next cut caught on fire, burning in the machine as I tried to put it out without water. Our final test was successful, producing the cutout below.

    But, when fit to the robot, issues became apparent. It was barely scraping the size limit, and while it fit over the wheel mounts, it failed to match the shape of the wheel. And, the shield grazed the ground, meaning that any rotation from the Superman arm would damage it or the arm. So, we created a second, smaller design and cut it using wood, resulting in a final design.

    Selective Intake

    Selective Intake By Evan

    Task: Design a new sorting mechanism for gold and silver particles

    The differentiation between the different shapes of minerals has been something we’ve been thinking about since day one. At the time we designed a box that allowed us to sort out blocks and balls by size, but weren't able to implement it. Our original selective intake only accepted balls so we only have to go to the one loading area, but our new design allows us to deliver both blocks and balls to their respected containers. It wasn’t implemented earlier because the robot just wasn’t tall enough. With our new belt drive, It’s possible to do.

    This we decrease the difficulty of TeleOp for the drivers by increasing the speed of deposit while decreasing accuracy needed. The selective intake also has a door built into it, which holds back the minerals until we’re ready to deposit. Gravity does the rest of the work, letting the balls fall down into a brachistochrone, and letting the cubes fall through.

    The other thing that we wanted to do was to have this process be almost completely mechanical, taking more stress off the drivers. The gate is released when a lever is pushed in and translated to a quicker motion with a pair of gears at a 2:1 ratio allowing for an easy deposit. The frame of the intake is made out of polycarb, bent with the sheet bender and cut into the correct form with the bandsaw.

    The intake also uses our ice cube design from earlier in the season. It is compliant and with its new 3D-printed supports (Ninjaflex, 20% infill), it will be much more effective than the previous intake. This time, instead of stapling the thing together, we are sewing it shut, which should hopefully negate any problems the previous version had, such as coming apart where the two sides met. The intake will be offset a little from the ice tray intake to allow for as much grabbing action as possible.

    Next Steps

    Now we must allow the drive team as much time to practice with it as possible.

    Pool Noodle Intake

    Pool Noodle Intake By Evan

    Task: Design a quick intake for the robot before competition

    The night before our final qualifier, we decided that the intake system on the robot was not up to our standards. To fix this issue, we poked some holes in a pool noodle, and put surgical tubing through it. While this was a quick and semi effective fix, it did have some problems, mostly due to the rushed nature of its construction. The tubing slid back and forth, and the noodle itself was slightly offset from the depositing box, causing it to be a little off. It could only be remedied by taping all the surgical tubing together, allowing it to grip the minerals better and allow for a smoother intake. The other big issue with this version of the intake was that the depositing mechanism was imprecise and required very accurate driver control and a little bit of luck.

    Next Steps

    This isn't a permanent solution, but we need to have something simple so that we can intake the gold and silver particles at the tournament. We plan to replace this with the actual corn on the cob intake after the competition.

    Latch Updates

    Latch Updates By Justin, Abhi, and Ben

    Task: Update the latch

    Our first attempt at a latch was made out of flat metal L brackets that would slide into the hook, but they slid off under any stress. We decided to make a latch with a ratchet and sprocket system. The easiest way to accomplish this was to 3d print it. There are two sprockets and the lander hook will slide in between them. This causes the sprockets to rotate and then lock, allowing the latch to support the weight of the robot. To disengage, the driver just needs to move the ratchet up and over the hook. The picture of the model shows our change in design because the right sprocket is mounted to a bearing in mount, while the left side has the bearing in the sprocket.

    The purpose of our new latch is to increase the speed of latching. The latch requires one direction of motion to fully engage it, making it perfect for autonomous. The latch also has room for error because the funnel shape of the fron plates guides the hook into the sprockets.

    Issues

  • bearings pop out under stress(fixed by moving bearings from sprocket mount to sprockets)
  • whole subsystem bends under stress(fixed by mounting the latch to aluminum instead of polycarb)
  • difficulty turning ratchet(fixed by trimming pieces)
  • Still not strong enough to support weight of robot in a match
  • Hard to get close enough to lander to engage ratchet
  • Next Steps

    We need to either strengthen our current design or find a better alternative.

    Superman Calculations

    Superman Calculations By Ethan

    Task: Calculate torque and other values of the Superman arm on our robot

    We want to have our robot completely replicable through the journal. So, we found it necessary to include the power calculations of various subsystems on our robot.

    Superman Arm

    The Superman arm uses two REV Core Hex motors to lift the robot upward, outputting a base 125 RPM and 6.4 Newton-meters of torque. Then, we have 15-tooth gears attached to the motors, which in turn connect to 125-tooth gears for a gear ratio of 10.4:1. Using the torque calculation WheelT=MotorT*(output/input), we find that the total torque exerted downward by the arm is 66.6 N*m.

    Then, given that the arm is .304 meters long, the upwards force produced by the Superman arm is 20.29968 Newtons. The robot itself weighs about 20 pounds, or 89 Newtons. But, since the robot is moving around its center axis, we can neglect the lower half of the robot that touches the ground with the wheels, reducing our load to 44.5 Newtons. Then, taking the integral of force with respect to the radius measured from the Superman arm, we integrate the equation force=(force at top/radius to top)*radius=292.763r. Using the limits defined by the distance to the edge of the robot (0 to .152 meters), the downward torque created by gravity is 3.38 N*m. Modeling the robot as a single point, we get this diagram.

    But, the robot doesn't always operate at optimal load. For example, when the robot is at maximum extension, there are about 60N of load above the center arm and the center arm itself is extended 18 inches, or .4572 meters. Performing the same integral as before with the new limits (0, .4572+.152=.6092), we find that the maximum possible downward torque exerted on the arm is 54.33 N*m, resulting in a net torque of 12.7 N*m upward. Superman can still raise the robot upward, but much slower and with a much greater probability of gear slippage. At these torque levels, the plastic teeth of the gears slip if they're not perfectly aligned.

    Given that the gears are composed of Acetal (Delrin/POM), that the area of one tooth is (.00104 meters * .011 meters = 0.00001144 m^2), that the arm produces 66.6 N*m * .152 m = 10.12 Newtons of force, and the Delrin/POM deformation chart, we can find that the pressure on *one* tooth of the gear is P=F/A=10.12/.00001144=884615.38 Pascals or .88461538 MPa. And, consulting the Delrin/POM deformation chart below, using the long-term line for an hour of use, we retrieve a stress of ~.5%, meaning that the teeth of the gears deform by .5% per hour of use. This alone explains our gear slippage under high loads; as the pressure on a tooth increases, they cause more deformation, which in turn results less area contact between the teeth of the gears, which results in more stress, causing a negative feedback loop.

    However, this alone doesn't explain the stripping of the gears - the gears would only deform by .0572 uM; more analysis is required. When we inspected the superman gears more closely, we found that the gears barely interlocked - maybe 1% of the gears were touching. When we go back to the pressure equation, we find that this increases the pressure on each tooth to 88 MPa. Under the short-term compression curve below, we find the strain is about 5%, or 10x the strain. This results in a deformation of about 5uM, but the contact area itself is only 104 uM, so under these loads it causes an appreciable effect.

    This leads us to the natural conclusion to solve this issue - the gears must be held tighter to increase the contact area and decrease stripping. To do this, we're starting to design a gear holder, which will be detailed soon.

    Gearkeepers

    Gearkeepers By Jose and Evan

    Task: Create and install gearkeepers to reduce slippage

    We need to install gearkeepers on the Superman arm to prevent gear skippage which damages gears over time. We designed a simple rectangle in PTC Creo and cut holes to fit bearings, 3D-printed them, and attached them.

    Now it was time to test for gear skippage. Unfortunately, we had one or two gear skips with every attempt of rotating the wheel mount. We tried using string to see if tensioning the gear holders would work but that also failed.

    We went back to the drawing board and checked for a sizing error. To calculate this we take the module of the gear and multiply it by the amount of teeth the gear has, then dividing by two to get the gear's radius. We do this for both gears and add them together. The module of the REV plastic gears is 0.75. This resulted to be (15×0.75/2)+(125×0.75/2) or 52.5 mm. And the original gear holders were 53 mm long, a slight error but at least we found the reason for error. We also noticed that there was some give in the plastic inserts for the REV bearings so we decided to tighten it down to 52mm.

    We changed the length of the inside of the gear holders from 53mm to 52mm and 3D printed them. This resulted in a complete fit where the gears were firmly engaged.

    Next Steps

    This is good for now but in the future, we need to watch the nylon of the gearkeepers for wear and tear as well as stretching - even a millimeter will allow the gears to slip.

    Mechanical Depositing

    Mechanical Depositing By Evan

    Task: Create a mechanical deposit for our selective deposit

    To relieve driver stress, we decided to put a mechanical release mechanism that would drop the minerals into the passive sorter to then further deposit them. The lever that activated the release mechanism was made of thick wire attached to a small gearbox that reversed the direction of rotation for the release gate. The lever activated the gearbox when it was pushed into the side of the lander. This created some issues that ultimately killed the mechanical release, such as a balance of tension that would never work out. We had to balance the tension of the rubber bands with the weight of the minerals while also accounting for the fact that the lever had to be pushed without our entire passive sorter being pushed beyond 180 degrees up and down.

    Because of the difficulty in implementing this, we instead switched over to a servo which now powers the release gate. While short-lived, it was a good test of the limits of our intake system, and we will be improving on it in the coming days.

    Next Steps

    We need to attach a servo to the intake with a correct mounting position to allow at-will depositing. We plan to do this with a inward-mounted servo which will then be connected to the REV hub through a wire protector, allowing us to place a servo high on the robot without worrying about the wires getting stuck in the gears and cut like before.

    Latch V.3.5 Assembly

    Latch V.3.5 Assembly By Ben

    Task: Assemble the V.3.5 latch and attach to the robot

    We assembled the fourth version of the latch today. Some of the improvements on this latch include using bigger bearings and thrust bearings inside. This latch is designed to be stronger and more reliable. After cleaning the parts and trimming some edges, we assembled the pieces. Upon assembly, we discovered an issue: the gears required a different amount of pressure to catch the lock. If left untreated, it could result in the robot falling off the hook. We determined the root of this problem was that the locking mechanism on the right gear was shorter than the left. To fix this, we trimmed a few millimeters off the piece that provides tension on the left gear to match that of the right gear.

    Latch attached to polycarbonate brackets.

    Next Steps

    We will need to perform various tests on the latch to determine if the height is correct, if the latch can support the robot, ease of latching and unlatching, and consistency. We plan to test our robot this Saturday at the DISD STEM Expo, which will provide an opportunity to practice latching.

    Fixing Mineral Dropper Components

    Fixing Mineral Dropper Components By Jose and Evan

    Task: Fix any issues with the mineral dropper

    At the STEM expo we saw a clear issue with the mineral dropper: it is very poorly geared and doesn't deposit minerals well. A quick look at the gear configuration revealed that the gears were attached in a poor manner such that there was a lot of gear skippage. To remedy this, we attached a gear-box to the dropper to keep the gears interlocked.

    The way the mineral dropper works is by having a wire attached to the shaft that turns the release be pushed when the robot hits the lander. The wire is attached with a portion of a gear custom cut for the job.

    We need to upgrade to a thicker wire for more reliable shaft rotations. After doing so we needed a different wire holder and we chose a REV wheel. After cutting it and drilling bigger holes to accommodate the new wire we needed to attach it all to the shaft for the mineral release.

    Next Steps

    We need to finish bending the wire and test its ability to open the mineral release when contacting the lander.

    Drive Testing at STEM Expo

    Drive Testing at STEM Expo By Ben and Abhi

    Task: Test robot performance at the STEM Expo to inspire younger kids and practice

    An FLL team gathered around Iron Reign’s robot

    We had the privilege of being a vendor and representing SEM at DISD's STEM Expo this weekend. Thousands of people cycled throughout our area during the day, so we had the opportunity to show off our robot to many people. Some of these people include FLL and VEX IQ teams, along with Best Buy volunteers. Our goal was to get kids excited about STEM and robotics, along with getting some robot practice in. We will be trying out the new latch, new presets, and prospective drivers.

    As soon as we started driving, we noticed a few issues. One of these being the belt drive repeatedly slipping. This may be a result of the belt loosening, the drive gear accelerating too quickly, heavy intake arm, or the preset causes the drive gear to keep operating, even when the arm is fully extended. We also struggled with keeping the intake box out of the way and prevent it from twisting around the “corn on the cob” intake. We will solve this by fastening the rubber band that was supposed to keep it in place. This; however, wasn’t our only intake problem. Once 2 minerals had been grabbed, they would usually fall out the intake box after lifting the arm. The intake box would turn vertical, making it easier for the minerals to shift out. This was especially an issue when trying to deposit the minerals, we would make several sudden movements, causing the arm to swing and minerals to fall out. A possible solution to this is adding a barrier between the floor of the intake box and the top of the box. This would allow for more freedom, as we could move faster without worry of losing minerals.

    Demonstrating intake arm for FLL kids

    Next Steps

    It will take a lot more practice to master latching and collecting, and even general driving. We will need to code better presets and either design a better collection box, or fix the existing one. Drivers will also have to be selected, which we will do by running several trials for each member and determining who is best at latching, scoring, and control.

    Latch 2.0 - Forged in Flame

    Latch 2.0 - Forged in Flame By Evan

    Task: Design a new latch for hanging

    Our latching system is too complicated to use quickly; it requires too much reliance on driver control and becomes jammed. So, we forged an iron hook to replace it. We started by taking an 8mm iron rod and placing it into the forge that we have, heating it up and bending it into shape over the course of an hour. We made a wire model for the hook, and then slowly and patiently formed the hook out of the rod. Then, to make an easy-to-drill connection point, we heated a section up until it was white hot and then used a punch to create a flat part that we then drilled into afterward.

    To create a mount, we took a length of steel and used an oxy-acetylene torch to heat up the areas we wanted to bend. Once this was done, we went about attaching the hook to the mount. We did this by finding the center of the mount, drilling it out, and pushing a bolt through it, surrounding all sides with washers. We then mounted a servo next to the hook and attached it with a piece of wire, which was secured to the hook by two notches cut out of either side of the tail of the hook. Later, after finding the wire to be too flimsy, we attached the two together with a strip of polycarb. It works well, allowing us to mount and dismount much easier than we would have hoped for with our last latch. While the last latch was purely passive and required no electrical components, this one gives us much more control in how we latch and delatch.

    Bigwheel Model

    Bigwheel Model By Justin

    Task: Design and update the Bigwheel Model

    We are updating our bigwheel model to represent our current robot. We had a model of just the chassis from the chassis study, so we are currently adding all of the changes we made throughout the season.

    Completed Changes

  • Added current intake
  • Added sorting system
  • Modeled the linear slide lift
  • Modeled superman arm
  • Future Changes

    The lift has been changed recently so the model needs to be updated. The main problem with this is that the new slides are not standard parts, so there are no accurate CAD files. This means we have to custom model our new slides to maintain accuracy with our model. The motor placement on the chassis needs to be fixed because we the measurements were estimates. There are many small 3d printed parts that need to be added to the robot, as well as our new ratchet latch.

    Next Steps

    We need to work on future changes and get our model up to date with our robot so we can start conceptualizing new subsystems.

    BigWheel Upgrades

    BigWheel Upgrades By Evan

    Task: Fix some issues on BigWheel before the build freeze

    We made more secure way of activating our hook, so we switched our piece of wire attaching the servo to the hook with a much stronger and less likely to bend strip of polycarb, which greatly improved the reliability of the hook.

    As well, we limited the back and forth motion of our slides at their attaching points. I achieved this by inserting a small piece of drywall sandpaper in between the stages of the slides. Hopefully, the added friction will create a stronger hold between the stages fo the slide.

    Next, we ground down a bolt to more securely attach the servo horn to the servo since it’s a REV hex shaft to servo adapter and the bolts we had didn’t fit inside well enough. Once that was done, we changed the ratio between the belt drive pulleys, going from a 1:1 (36 teeth to 36 teeth) to a 5:3 (60 teeth to 36 teeth) by increasing the size of the pulley at the motor. This should increase the quickness of our lift and hopefully let us squeeze a few more mineral pick up and depositing cycles in.

    Next Steps

    It's time to turn the robot over to the coders and drivers, so there won't be many changes after this,

    Pulley Spacers

    Pulley Spacers By Ethan

    Task: Design and implement pulley spacers to prevent belt interference

    We had an issue where the belts that allowed our arm to slide upward were misaligned, resulting in the belts frequently slipping. We narrowed the slippage down to a single point, at this pulley.

    We had to create a new spacer to keep that section of the belt inline with the rest. As usual, we took measurements and replicated them in Creo. It had to be about 3.5 centimeters long, the same width of the metal plate. The depth of the indentation to attach to the linear slide is about 0.75 centimeters and the diameter of the M3 holes 3 millimeters. With these measurements, we designed the piece and printed it in 60% infill nylon, strong enough to withstand the weight of the linear slides. This is what version one looks like:

    However, this version's holes were too far down, allowing the toothed sections of the belts to interact and jam. So, we decreased the height of the bottom pulley-holes so that the middle section of the belt would slider higher up, preventing interference. This resulted in the final version seen at the top of the article.

    Next Steps

    We still have to fully test these spacers, but we can't do a full test until we fix the gears supporting the elbows, which will be detailed in another post.

    Elbow Rebuild

    Elbow Rebuild By Ethan, Jose, Karina, and Ben

    Task: Rebuild the elbow after total gear annihilation

    In a previous post, we detailed the extent to which we had stripped our gears - they were missing teeth in several places and the black anodization layer had completely stripped away. So, we had to replace them. The first order of action was to design gearkeepers for them. We've designed gearkeepers before, for the Superman arm, but these have different requirements. They must connect the gears on both elbow driver and slave, but also must mount to the robot itself to prevent the motor shaft from wobbling, which had previously caused major issues. We came up with this design, printing it out in 60% infill nylon.

    The next thing to do was replace the actual gears. To do so, we had to dismantle the entire elbow and replace the gears and shaft collars. This alone took about two hours per side. We added the new gears, ensuring that they were in alignment, and printed a circular part to mount the top of the gears to the linear slide so that the entire system would rotate when the gears were turned. Then, we remounted the belts and aligned them. After, we attached the new gearkeepers, ensuring that the gears interlocked perfectly.

    Next Steps

    So far, we haven't experienced issues with the new elbow, but we're getting our hands on a new set of gears to be safe. We expect this system to continue to work for the Regional tournament, and are performing drive practice to ensure this.

    Latch Designs - A Retrospective

    Latch Designs - A Retrospective By Ethan

    Task: Analyze past successes and failures in our latching system

    Version 1

    The first version of the latch worked decently. We started out with the idea of a one-way, passive latch. This idea involved mounting smaller bearings and gears between them, with a spring-like nylon piece that moved only when downward pressure was placed upon the gears. This design was only fully realized before the Wylie Qualifying tournament, and only tested the night before. We found that the bearings popped out under pressure necessitating a reset after every match and meaning that we could only latch once per match. We opted for the endgame latch, as it was more reliable. But, this cut the amount of points we could receive immensely. After the tournament, we decided to do a full redesign.

    Version 2

    The second version's changes were simple. We redesigned the nylon "spring" and made it thicker and more prominent. This made it so the latching gears were more firm than before, which in turn allowed more weight to be put on them. However, the issue with the gears was still present; as the load on the latch increased, the nylon would bend more and more, allowing the bearings to fall out so that the latch would jam in place. This version was quickly scrapped.

    Version 3

    At this point, we were sick of the bearings popping out. So, we widened the holes immensely to fit larger bearings which in turn had larger holes allowing for bolts to be run through. This was overkill, but it ensured that no slippage would occur during normal robot usage. Again, we also thickened the nylon "springs" so that the gears would stay in place without significant upward force.

    We realized, that while technically impressive, the latch as we knew it had to go. It worked, but it was too time-costly to justify using, as the driver had to precisely line up the bot next to the lander to use it, taking about 20 seconds. In addition, it was difficult to code as it required several intricate simultaneous robot operations: the lift needed to descend at the exact same moment Superman needed to rotate, all while the elbow rotated the robot 90 degrees. In summary, it was an overly burdensome task. So, we threw away all that work, these past two months of labor in favor of a simpler option.

    Version 4 - the Hook

    We decided that it was time to go back to the drawing board. In time periods, it was approximately a jump from the current era to the Iron Age. So, we designed appropriately. We designed a stainless steel hook, first making one out of prototyping wire. Then, we heated up the forge, adding plenty of coke, and set to work. We chose a stainless steel rod, 8mm in diameter and warmed it to red hot, beating out the initial design. We let the initial rod air cool so that it would be soft enough to drill through, creating the mounting point for the robot. Then, we reheated it to its critical point (when it loses its magnetic properties) and quickly quenched it to reharden it. But, simply quenching it makes the steel too brittle to use in competition, so we finished up the hook by tempering it, using an oxy-acetyline torch on it until the surface became matte. Finally, we had the hook seen above. After all that work, we'd gone with the simplest option because sometimes, it is the best.

    Up-to-Date Bigwheel Model

    Up-to-Date Bigwheel Model By Justin

    Task: Finish the Bigwheel model

    Updating the Bigwheel model to the robot’s current configuration was a challenge. The new linear slides are not standard parts, so we had to model them from scratch. There was some cleaning up that was needed on the drivetrain of the model. This was mainly attaching floating motors to motor mounts and axles to bearings. These were mainly cosmetic changes, but they help define the purpose of the different parts of the drivetrain. We also updated the intake assembly to our current ice cube tray intake. The structure of the intake was easy to model but the ice cube tray gave us some trouble with its unique shape and pattern. The ratchet latching system was a failure, so a new hook model was needed. The main issue with this was that we custom forged our new hook, so there was some difficulty in getting the model to accurately represent the capabilities of the hook. Another challenge was the mineral storage system. This is made from polycarb pieces and has many unique pieces, so arranging the pieces to accurately show the flow of minerals was difficult.

    In addition to updating the model, we also learned how to show the different movements of the robot with the model. Mechanical constraints were added to allow certain parts to slide or rotate. The one problem we had with this was that there were no limitations to how far something could slide or rotate, so many parts of the model would disconnect and be left floating. After some research, a solution was found. Zero points were created for each moving part and minimum and maximum movement limits were added. Some parts that now can move on the robot are the wheels, superman arm, hook, and linear slides. This allows us to not only show the movement of the robot, but also the limitations of its parts, which can help us visualize new solutions to our remaining problems.

    Next Steps

    Our next step is to wait for more build changes, so we can keep updating the model. Another addition we might make is making stress maps of the robot in different configurations to see where parts might fail. This has been an ongoing challenge of keeping the model accurate when the robot gets updated or rebuilt, and now we finally have a finished model and ready robot for regionals.

    Road to Worlds Document

    Road to Worlds Document By Ethan, Charlotte, Evan, Karina, Janavi, Jose, Ben, Justin, Arjun, Abhi, and Bhanaviya

    Task: Consider what we need to do in the coming months

    ROAD TO WORLDS - What we need to do

     

    OVERALL:

    • New social media manager (Janavi/Ben) and photographer (Ethan, Paul, and Charlotte)

     

    ENGINEERING JOURNAL: - Charlotte, Ethan, & all freshmen

     

    • Big one - freshmen get to start doing a lot more

     

    • Engineering section revamp
      • Decide on major subsystems to focus on
        • Make summary pages and guides for judges to find relevant articles
      • Code section
        • Finalize state diagram
          • Label diagram to refer to the following print out of different parts of the code
        • Create plan to print out classes
        • Monthly summaries
      • Meeting Logs
        • Include meeting planning sessions at the beginning of every log
          • Start doing planning sessions!
        • Create monthly summaries
      • Biweekly Doodle Polls
        • record of supposed attendance rather than word of mouth
      • Design and format revamping
        • Start doing actual descriptions for blog commits
        • More bullet points to be more technical
        • Award highlights [Ethan][Done]

    Page numbers [Ethan][Done]

        • Awards on indexPrintable [Ethan][Done]
      • Irrelevant/distracting content
        • Packing list
        • Need a miscellaneous section
          • content
      • Details and dimensions
        • Could you build robot with our journal?
        • CAD models
        • More technical language, it is readable but not technical currently
    • Outreach
      • More about the impact and personal connections
      • What went wrong
      • Make content more concise and make it convey our message better



    ENGINEERING TEAM:

     

    • Making a new robot - All build team (Karina & Jose over spring break)

     

      • Need to organize motors (used, etc)
      • Test harness for motors (summer project)
    • Re-do wiring -Janavi and Abhi
    • Elbow joint needs to be redone (is at a slight angle) - Justin/Ben
      • 3D print as a prototype
        • Cut out of aluminum
      • Needs to be higher up and pushed forward
      • More serviceable
        • Can’t plug in servos
    • Sorter -Evan, Karina, and Justin
      • Sorter redesign
    • Intake -Evan, Karina, Abhi, Jose
      • Take video of performance to gauge how issues are happening and how we can fix
      • Subteam to tackle intake issues
    • Superman -Evan and Ben
      • Widen superman wheel
    • Lift
      • Transfer police (1:1 to 3:4)
      • Larger drive pulley
        • Mount motors differently to make room
    • Chassis -Karina and a freshman
      • Protection for LED strips
      • Battery mount
      • Phone mount
      • Camera mount
      • New 20:1 motors
      • Idler sprocket to take up slack in chain (caused by small sprocket driving large one)
    • CAD Model



    CODE TEAM: -Abhi and Arjun

    • add an autorecover function to our robot for when it tips over
      • it happened twice and we couldn’t recover fast enough to climb
    • something in the update loop to maintain balance
      • we were supposed to do this for regionals but we forgot to do it and we faced the consequences
    • fix IMU corrections such that we can align to field wall instead of me eyeballing a parallel position
    • use distance sensors to do wall following and crater detection
    • auto paths need to be expanded such that we can avoid alliance partners and have enough flexibility to pick and choose what path needs to be followed
      • In both auto paths, can facilitate double sampling
    • Tuning with PID (tuning constants)
    • Autonomous optimization



    DRIVE TEAM:

    • Driving Logs
      • everytime there is driving practice, a driver will fill out a log that records overall record time, record time for that day, number of cycles for each run, and other helpful stats to track the progress of driving practice
    • actual driving practice lol
    • Multiple drive teams

     

    COMPETITION PREP:

    • Pit setup
      • Clean up tent and make sure we have everything to put it together
      • Activities
        • Robotics related
      • Find nuts and bolts based on the online list
    • Helping other teams
    • Posters
    • Need a handout
    • Conduct in pits - need to be focused
    • MXP or no?
    • Spring break - who is here and what can we accomplish
    • Scouting

     

    Issues with Driving

    Issues with Driving By Cooper, Jose, BenB, Bhanaviya, Karina, and Justin

    Task: Widen Superman's wheels and plan the new robot

    Since we just qualified, we have a lot to do. On the list for tonight, between the 6 of us, we have:

  • Teaching Cooper how to write a blog post
  • Work on the model of the new robot
  • Widen the superman wheel
  • Start the bill of materials'
  • Ben and Karina worked on widening the Superman wheels by adding 2 omniwheels on either side of a newly cut shaft. This will help stabilize the robot when moving into the extended position, along with preventing falls in the future. We hope this will make it easier to drive the robot and make it more reliable. As well, we began to make the Bill of Materials for the new robot.

    Bhanaviya trained Cooper how to write and upload a blog post. Justin worked on the model for the new robot.

    Next Steps

    Next, we will work building the worlds robot.

    VEX 393 Motor Testing

    VEX 393 Motor Testing By Jose, Cooper, Aaron, and Janavi

    Task: Test VEX Motor 393 as a faster servo for intake

    We need to speed up our intake to spend less time in the crater collecting minerals. We can accomplish this using VEX 393 Motors with high speed gears integrated, these motors are great since they count as servos, not motors. In terms of progress, this is what we did:

    • Tested VEX Motor 393 with servo cable on BigWheel
    • Resoldered XT-30 for servo power injector cable
    • Built new cable for servo power injector
    • Did research on VEX Motor 393 Controller to find out how it works
    • Replaced gears of VEX Motor 393 with high speed gears
    • Researched how to troubleshoot VEX Motor Controllers
    We are having issues implementing these motors onto BigWheel and our troubleshooting efforts did not suffice our needs.

    Next Steps

    We need to plan how to replace the servos on the intake with the VEX 393 Motors and test their functionality.

    New Robot Base - Icarus

    New Robot Base - Icarus By Evan, Justin, Aaron, and Ethan

    Task: Build the base for the new robot

    Since BigWheel was never intended to be a competition robot, we decided to build an entire new robot based off of it. This means that the base plate of the robot is going to have to be the most accurate part of the robot since everything after that has to be built upon it. To do this, we started out by measuring the base of our original robot, then squaring the whole thing out, making sure it was uniform across the base, down to 1/32". The inner slot that houses the superman lever was done down to 1/16" because it’s precision was not as important; it houses the Superman arm's wheels.

    We cut and trimmed the basic platform using the table saw and clipped some of the thinner excess polycarb off with flush cutters. Once the base was cut to size, we moved onto the bends. The bends were measured exactly where they are on the outside of the current robot. To make precise cuts, we took a trip to the Dallas Makerspace. There, we used the sheet bender to bend our 1/8" polycarbonate which makes up the base, into shape. The walls of the base are then going to be connected to square aluminum piping that has been ripped in half to create the outer wall.

    The task of holding the sides together will be done by two 3D printed parts that will house the LED strip that goes around the outside of the robot (used to communicate to the driver which mode we are in). This base will be much more precise than our previous chassis, making it more reliable as well. Finally, the new base will have more mounting points than before, allowing for greater modularity. The old robot will be a sparring partner for driver practice. The level of craftsmanship that has gone into this baseplate is industrial grade, we have done something comparable in precision and accuracy to any product meant to be mass produced. We can only hope that our final robot works as well as it's intended.

    Next Steps

    To have a fully supported base, we need to add the framing brackets and the wheels before it can be considered a wrap on the base section of the robot.

    Finishing Icarus' Base

    Finishing Icarus' Base By Evan, Aaron, and Ethan

    Task: Perform the final steps to complete Icarus' base

    Since we finished the polycarb base, our robot went through some major changes. We last left our robot in the post-bend stage, just a piece of polycarbonate. The first thing we did was to square the whole robot with side brackets. These cleanly ripped aluminum C channel side brackets now serve as the highly accurate frame of our robot, which has been measured down the millimeter for the highest level of precision yet.

    After creating the side brackets, it was time to give them the right holes in all the right places. The holes for the rod we use as our drive shaft were drilled in the side brackets, exactly the same on either side, as were the holes for the points of attachment on either side of the robot, connecting the base to the brackets. The front bracket was cut to size and placed on the robot after the REV rail we use as an attachment point for the elbow joint was placed. Then we put the 3D printed brackets onto the REV rails that make up the back end of the frame of the robot, running the bar that became the axle for the wheels. If you want to see just how far we’ve come, you can look back at the article that Arjun and Karina wrote about building the first version of the robot over the summer. The amount of improvement is large and part of the journey. Everything on the robot is done for a reason, be it stability, weight, or efficiency. This time around we’ve significantly reduced the number of extra things on the robot, and simplified it as much as we possibly can.

    Next Steps

    The next step is going to be told in an upcoming article that will describe the process of building the arm mount. If this robot is going to be on the field and compete, it needs the elbow joint to be constructed, so that’s next on the evolution of the new robot.

    Bill of Materials

    Bill of Materials By Bhanaviya and Karina

    Task: Create a list of parts needed for the new robot

    To determine all the materials we need for the new robot, Karina and I started a Bill of Materials. To do this, we first analyzed Big Wheel sub-system by sub-system. We determined the parts used for each sub-system and placed it into a spreadsheet. Upon doing this, we needed to get each part's exact measurements so that we could save time when trying to cut the new parts. Additionally, we needed the quantity of each part as well as which manufacturer it was from. This was critical because at the end of the day, the task was to build a better version of Big Wheel but using, more or less, the same parts.

    New Elbow

    New Elbow By Justin

    Task: Design an elbow for bigwheel that we can 3d print

    To speed up the build process of the new robot, we made a 3D printable part of the elbow joint. The design simplifies the complex assembly of the elbow mounting point and makes it a single printable part. The old elbow contains many different parts that would need to be spaced precisely in order for the gears to mesh properly, while the new print allows us to stay consistent with our measurements when building the new robot. The part contains motor mounting holes, as well as a socket to support the weight of the motor. There is also a place to put the bearing that the lift system rotates on.

    This had to be spaced properly so we calculated the exact distance by using the number of teeth and module of the gear to find the diameter. The part also has two places to attach it to a REV rail, which allows us to secure the elbow to the chassis. The spacing between the bottom REV rail socket and the bearing hole is spaced so that the gear that aligns with the bearing is flush with the front plane of the robot to stay within 18 inches. The new bearing hole is also higher up than the hole on the old robot, which gives us more extension when intaking or depositing minerals.

    Next Steps

    We need to attach the new mounts and test how the new height of the elbow mounting point affects our balance and latching.

    Constructing Icarus' Elbow

    Constructing Icarus' Elbow By Evan, Aaron, and Ethan

    Task: Build the elbow for intake

    In the last Icarus' blog post, it was just getting the basic flat, support frame of the robot. The next step in the construction of Icarus' is the elbow joint that holds the intake. This time around, we simplified everything significantly as compared to BigWheel, reducing the excessive aluminum parts to two 3D printed parts. We attached these to the REV rail that runs across the front of the robot with two smaller REV rail parts we custom cut to fit the size of the 3D part. Then, we inserted the motors that each of them requires. Here we are using the same REV HD motors we used for our elbow on the last robot since they worked quite well. After inserting these, we went about supporting the elbow frame, which was done with two REV rails attached to the robot from the top of the 3D printed piece.

    These were attached at a 30-degree angle and anchored to the robot behind the two drive motors we use for the wheels. Once both of these were secured, we began assembling the arm. The arm itself has remained mostly the same, consisting of two linear slides on either side for a grand total of four, extra smooth slides. We drilled out the correct holes on all of the arm pieces, created four custom metal parts for the slides, which took a while on the bandsaw, and then assembled the bottom slide of the arm. Three holes were drilled out in four REV 86 toothed gears, which work as the mounting point of the linear slides. Once these were attached, we attached all the other necessary parts for the arm and life on the elbow joint’s 6mm hex axle that protrudes from a ½ inch hex axle set on two bearing with ½ inch hex inlay for an insanely smooth rotation. After all the necessary hardware was set in place, we put a redesigned version of our 3D printed gear keepers on to keep the distance between the motor shaft and the rotating shaft the same, and the gears firmly interlocked. During the time frame of this article, the new superman lifting lever was put into place.

    Next Steps

    The next step in the saga of the robot is the hook and the new intake, which will be seen in upcoming articles. As well, if the robot is to score at worlds, we need to construct the arm lift for the intake and then the intake itself, which will be redesigned and improved. Also, some wiring would be nice.

    Icarus' Superman Arm

    Icarus' Superman Arm By Evan, Aaron, and Ethan

    Task: Design and install a lifting arm for Icarus

    At the same time as the elbow joint was being done (which can be found in the article "Constructing Icarus' Elbow”) the Superman lift was being installed in the back half of the robot. The old superman system was difficult to install, but we designed it to be slightly easier. Mounting brackets were already pre-set in the robot so we didn’t have to disassemble half of the robot to be able to set screws into the extrusion rail. Bearings were inserted into the brackets, and the process of sliding all of the needed parts onto the rails began. First was the outside shaft collar, which holds the 6mm hex shafts in place. Then was the first interior shaft collar, which kept the internals in place. Then the first of the gearkeepers was put on, followed by a spacer meant to separate the gearkeeper’s bearing from being popped out by the gears on the Superman arm. Then came the actual Superman arm, which is one centimeter longer than our original arm, hopefully allowing more lift.

    It’s made of three 125 toothed gears from REV, with the center one’s ridges drilled out, a REV rail sized chunk sawed to insert our actual lever bar, and 3D printed spacers separating each of the gears around the outside which have all been bolted together. On the end of the bar is a 3D printed holder for the four omni-wheels we’ve positioned there, which are all set with bearings for smooth motion. Once this was slotted onto the 6mm hex rail we added one more spacer, the other gearkeeper, then the final interior shaft collar. It was put through the other bearing and bracket on the other side and finally closed off with a lost final shaft collar on the outside.

    After we got the arm in, we moved on to the driving 6mm hex shaft. Since this one was a lot longer and was hard to fit into the space provided, it was aligned in a way that it could slip through the slots of the wheels as we pushed it into place. We first put a REV core hex motor and a shaft collar that would work as the outside clamp. Then we put it into the bearing on the bracket and pushed it through. A shaft collar was placed, and then we attached the other end of the gearkeepers on. It was tight like we wanted it to be, but it didn’t make our builder lives easy. We put on a spacer to keep it in line with the Superman arm and then we put on the drive gears, three 15 tooth gears with the center one's sides cut off to mimic the Superman gears on the other side. After we put that in, we put another spacer and then the other side’s gearkeeper. This is where the struggle came. Since the gearkeepers keep the gears together exactly the distance from the center of the radius of the 15 toothed gear to the center of the 125 toothed gear, it was a very tricky squeeze to get it attached. After we managed to get it one, we put another shaft collar on and put it through the bearing on the other side. We slid on one last shaft collar on the outside, and ended the shaft with another REV core hex motor. That capped the entire subsystem off, and all that’s left is it to be wired.

    This system differentiates us from other teams - our robot is able to deposit through a lever arm that rotates the robot itself, adding an additional degree of sophistication and mobility to the robot.

    Next Steps

    The subsystem needs to be completely wired and tested before it's approved for the final robot.

    Meeting Log

    Meeting Log March 28, 2019 By Cooper and Evan

    Meeting Log March 28, 2019

    Today's Meet Objectives

    Objective Summary

    Fix camera mount, attach lift motors, make custom cables for the drive motors, and forge the hook

    Today's Work Log

    • Fix camera mount on BigWheel
    • We've had a problem for while where the camera on BigWheel gets loose, and falls out. Cooper decided that a clamp, like the one we had before, just better executed. Cut out of a spare piece of 4 mm Polycarb, and tightened by a m3 screw, it holds the camera in place without even the slightest wiggle. This will help keep our vision more consistent.
    • Mounting elbow motor
    • Evan in the time being mounted the lift elbow motors on Icarus. This means we can start to make the arms.
    • Make custom Cables for Icarus drive motors
    • Cooper worked on cutting down the motor cables of the Andy mark motors used for driving. This will help keep clutter down from how bad it was on BigWheel
    • Forging new hook
    • Evan and Cooper worked on forging a new hook. It took two iterations, as the first became brittle and snapped, but the second one was fine. This new hook will go on Icarus, and will allow us to practice sooner

    Reverse Articulations

    Reverse Articulations By Abhi

    Task: Summary of Icarus Movements

    In post E-116, I showed all the big wheel articulations. As we shifted our robot to Icarus, we decided to change to a new set of articulations as they would work better to maintain the center of gravity of our robot. Once again, we made 5 major deployment modes. Each articulation is necessary to maintain the robot's center of gravity as its mode of operation shifts.

    The position seen above is called "safe drive". During normal match play, our drivers can go to this position to navigate the field quickly and with the arm out of the way. In addition, we use this articulation as we approach the lander to deposit.

    When the driver control period starts, we normally navigate to the crater then enter the intake position shown above. From this position, we can safely pick up minerals from the crater. Note that there are two articulations shown here. These show the intake position both contracted and extended during intake.

    During the end game, we enter a latchable position where our hook can easily slide into the latch. After hooked on, our robot can slightly lift itself off the ground to hook. This is the same articulation as before.

    At the beginning of the match, we can completely close the arm and superman to fit in sizing cube and latch on the lander. This is the same articulation as before.

    These articulations were integrated into our control loop just as before. This allowed smooth integration

    Next Steps

    As the final build of Icarus is completed, we can test these articulations and their implications.

    Icarus' Arms

    Icarus' Arms By Evan, Aaron, and Ethan

    Task: Install intake arms

    Since the last post, in which we installed the Superman Arm, we've installed the second stage of the linear lift and the belt drive that accompanies it. We began by drilling two holes in the linear slides that were exactly the space between the holes on the carriages for the linear slides using a drilling template we printed on the Tazbot printer. We did this to two of our linear slides, and then attached them. We realized that they were too long and sticking out of the 18x18x18 sizing box, so we detached them and cut off a centimeter from the top and ground off the edges. They were reattached successfully, and the 3D mounts for the belt system were installed at the same time since they use the same point of attachment as the linear slides.

    Those custom pieces that were mentioned in the Joint Operation article were now utilized, attaching to the top of the first linear slide and to the carriage of the second linear slide. These parts are used for the attachment of the pulley bearings that the belt drive relies on to function. We installed these pieces rather easily but struggled on some of the tighter fits that were done to reduce wiggling in the arms, a problem that the last robot had. The next thing we added was the physical belt which drives our lift. The belt was tied off on the final carriage on the second linear slide on either side. The next step was to create the mounting for the motors that would drive the lift. To do this we set up a REV rail under each of the elbow motors, and then topped it off with another rev rail that we connected to the elbow frame supports that run from the front to the back of the robot. Then we mounted the motors, two Orbital 20 andymark motors, which at first didn't fit. The issue was that there was no way to mount them close enough for a belt to be put in place with the current gear keepers we had on the robot. They were attached, and then the motors were mounted, and the belts were put on. The lift has the same ratio as last time, which is further explored in the article Bigwheel Upgrades. The whole system is much more cleaned up and simplified, and generally looks a lot better.

    Next Steps

    The next challenge for us is going to be making the hook, attaching said hook, and redesigning the intake in time for effective driver practice.

    Wiring Icarus

    Wiring Icarus By Jose, Abhi, Evan, and Aaron

    Task: Wire Icarus to be functional and move utilizing code

    With the construction of Icarus nearing completion we need to start connecting wires from the motors and servos to the REV Expansion Hubs before it becomes impossible to do so.

    • As soon as the expansion hub were placed on the chassis, servo wire extenders were connected before anything blocked us from doing so
    • We used custom sized wires to avoid a mess of wires that were way too long
    • We connected all the motors and servos in the same configuration as we had on BigWheel to keep everything consistent and make coding Icarus easier

    Despite our preemptive measure we encountered several problems when testing Icarus using tele-op control:

    • The polarities on the wires were reversed and this couldn't be fixed in code as the encoder values would be affected by this
    • There was a lot more lag than usual on Icarus, this affected the intake arm as its movement is time-based
    • The speed of the wheels were a lot faster now that we are using a different gear ratio and motor, however unlike the other problems, this can be fixed in code

    Next Steps

    We need to reverse the polarities on all the motor cables and try the fix the lag and speed issue with code.

    Intake Flappers

    Intake Flappers By Jose, Evan, and Abhi

    Task: Design and test intake flappers to speed up mineral intake

    Due to our new intake articulation involving the superman wheel the ice cube tray intake is slightly too elevated to intake minerals. To fix this we designed small flappers out of ninja flex(the Iron Reign way) to help the intake reach further. Tests prove this intake to be quicker than the ice cube tray alone and it should suffice for the UIL State championship tommorow.

    Next Steps

    We will compete at UIL and see if the new intake works

    UIL 2019 Postmortem

    UIL 2019 Postmortem By Ethan, Charlotte, Evan, Janavi, Beno, Benb, Bhanaviya, Abhi, Arjun, Jose, Aaron, Paul, Cooper, and Justin

    Task: Reflect on what we did correctly and incorrectly at UIL

    Pit & Packing & Roles

    • Pack more robot parts - didn't have enough to repair Superman arm
    • Pack more tools - needed soldering iron to repair voltmeter
    • Better organizational system - we couldn't find tools easily
    • Need handouts - see tokens post
    • Need team visibility - get shirts for freshmen, get people in stands
    • Need responsibility for clean pit - messy pit made robots repairs much harder
    • Need preassigned roles for team members on game day - reduce confusion
    • Need better scouting system - use Google Forms and live scouting

    Robot & Game

    • Need to repair Superman arm - gears stripped in match; will replace with metal gears
    • Need to install linear slide belt protector - belts got stuck on lander
    • Intake needs to be clear - remove friction tape
    • Need to reduce sorter bar in intake - reduces visibility
    • Need driver practice - reduce simple errors
    • Need auto setup practice - reduce simple errors
    • Need new team marker - old one did not fit in intake

    Code

    • Need to enhance lights system for teleOp - better driver knowledge
    • Need to calibrate anti-tipping method - not adapted for Icarus
    • Need to slow crater-side auto - prevent crater parking mishaps
    • Need to calibrate depot-side auto - options when working with other teams
    • Need to find Superman-linear slide equation - easier articulations
    • Need to simplify controls - automate intake, deposit for driver accessibility

    New Superman Arm

    New Superman Arm By Ethan and Evan

    Task: Redesign the Superman arm to be more robust for Worlds

    In posts E-116, we found that we were putting pressure on the individual teeth of the Superman gears on the order of mPa. We designed gearkeepers to ensure that the gears would interlock and reduce pressure, and these worked for awhile. However, under tournament pressures at UIL, the teeth on the smaller gears broke entirely - between the teeth that composed the gearing-up portion, at the beginning we had 45. At the end, we had 15 teeth.

    This necessitated a total redesign. Upon coming back from UIL, we created a new version of Superman with metal Tetrix gears with a 3:1 ratio - the aluminum Tetrix uses has proven much tougher in the past. To compensate for the reduction in gear ratio, we removed the old Core Hex Motors and replaced them an NeverRest+BaneBots 104:1 motor+gearbox combination. Coming off the bat, the NeverRest outputs .17 N*m, and with the gearbox, it outputs .17*104=17.68 N*m. With the 3:1 gear ratio, it outputs 53 N*m, matching the previous Superman arm while increasing tooth durability.

    This new Superman arm will allow us to rotate the entire body of our robot around the axis of its wheels, allowing us to reach the lander without difficulty and ensure redundancy on the robot. The Superman arm is the centerpiece of our robot; it allows us to utilize Balancing, Center of Gravity Calculations, and Articulations in a truly innovative way.

    Next Steps

    We need to test the arm to make sure no additional stripping occurs.

    Intake Update

    Intake Update By Ethan

    Task: Custom design an intake to improve intake times

    In testing, we found that the intake didn't perform adequately - the balls would slide back out in the inverse articulations. So, we designed attachments for the corn-cob intake out of ninjaflex, figuring that small tabs would hold the minerals in better. It failed - they were too compliant - but we found it was much easier to intake minerals than before due to the high coefficient of friction.

    So, we decided that the corncob base was the issue. We designed a circle with the diameter of the previous corncob aligners and attached thicker tabs on the outside, creating the stl seen above. When tested, this was much less compliant than the previous beater bar, which served to make intake easier. In addition, the combination of reinforced tabs and ninjaflex prevented the minerals from falling out of the intake through increased coefficient of friction.

    Next Steps

    We plan to reattach this to the robot to do driver practice.

    Machining Gears for Superman

    Machining Gears for Superman By Ethan and Justin

    Task: Machine replacement gears for Superman

    Shortly after creating the new Tetrix gear system, we got a response from one of the CNC shops we'd reached out to, offering to machine the 15 and 125-tooth REV gears from the STEP files. So, we took the Superman system off of our old robot, BigWheel, and sent some of the broken 15-tooth gears from UIL.

    In response, the shop sent us the new gears the next day, with added modifications for mounting the gears onto REV extrusion. These gears will make the arm much stronger, making it more robust and able to withstand the shear pressure on the teeth.

    Next Steps

    We need to mount the gears and test them to ensure stability.

    Ninja Flex Intake V2

    Ninja Flex Intake V2 By Jose, BenB, Karina, Evan, Abhi, Ethan, Charlotte, and Aaron

    Task: Design, implement, and test a newer version of the ninja flex intake

    The new ninja flex intake is good, but it has room for improvement. One issue is that it is too big and minerals have some problems entering the intake tray, Another issue is that the spacing of intake gears is too much and cuases minerals to be intaked slower. We fixed this by using smaller intake gears and using six of them instead of five. After replacing them we could test the new and improved intake. Results showed a much faster intake speed with an average intake time of 1-2 seconds. This was a major improvement and most likely the intake's final iteration.

    Next Steps

    Now with a finished intake we can drive test to see its functionality in a real match.

    Meeting Log

    Meeting Log June 08, 2019 By Bhanaviya, Jose, Paul, Aaron, Ben, Evan, Trey, and Justin

    Meeting Log June 08, 2019

    Task: Prepare for the 2019-2020 Skystone season

    Today kicked off our first meeting for the new Skystone season. Since the actual challenge for this year hasn't been released, the most we can do is to speculate what the new challenge might pose, and what we can do to prepare for it.

    Recruitment

    With most of our upperclassmen graduating, the SEM Robotics program needs more members. As the varsity team in our program, we will be responsible for spreading the word about out program in our school - The School of Science and Engineering. This includes making posters, finding a suitable room to host an interest meeting, and planning a presentation to explain the commitments that come with being a part of a FIRST Tech Challenge Team.

    Prototyping leg-drive

    Just like Relic Recovery, we suspect that this year's game will be a stacking game (especially considering the fact that the phrase 'Together we RISE' was stressed in the teaser that was shown at the World Championship last season). A stacking game requires a relatively tall robot (by robot standards anyway), and a tall robot means a leg drive. Leg drive is an idea we've joked around with but summer is also the best possible time to test any impractical ideas. So, Aaron, Trey, Justin and Evan experimented with the leg drive system by prototyping leg propulsion with polycarb "legs". The polycarb pieces were drilled to form a rectangular shape which would extend and contract to propel the drive forwards. After creating the polycarb structures, they implemented rev rails and gears to "rev up" the leg drive system. It's still a prototype for now but it could be implemented into a chassis soon to test if the leg drive system can actually be made into a functioning model.

    Experimenting with grippers

    A good stacking bot also needs reliable grippers. Given our team's track record for exploring multiple build ideas at once, we figured that the new season would have us testing and innovating a good number of gripper systems. Fittingly, Jose and Ben tried out two different kinds of gripper systems. Jose prototyped a parallel gripper bar system. He used polycarb pieces to create the prototype. Two smaller vertical pieces of polycarb were attached onto a horizontal, larger strip to create the parallel gripper system. Ben implemented a loop gripper system onto a small base chassis with 2 omnis and 2 REV wheels. The loop gripper operates when the REV motor spins the gear sprocket attached to a carbon-fibre rod which causes the ziptied-loop to expand and contract accordingly.

    3D-Modelling and CAD Design

    Paul modeled a standard REV for leg drive. This past season, we have used this kind of bracket repeatedly - as such we decided to model it in the case that we choose to incorporate it in our design for the upcoming season. In the case we do decide to experiment with multiple drive trains and gripper systems once the new challenge is revealed, having stock of 3D printed parts would allow us to test out multiple ideas even if we don't have the actual part with us.

    Next Steps

    We've designed 3 prototypes over the course of today's meet so this gives us plenty to test over the next upcoming meetings. However, we are participating in several outreach events over the next few weeks so finding time for testing will be tricky. But if our speculations for a stacking game are correct, we think our build season has gotten off to a good start so far.

    Leg Drive Prototype

    Leg Drive Prototype By Jose

    Task: Prototype a Leg Drive for next year's (possible) stacking game

    Although most teams go for a traditional chassis, a different type may be needed for next season as speculations suggest a stacking game. A leg drive would be an apt idea to test out for such a game For this chassis, two motors spin their respective "leg" attached to a gear. The point is move the robot using the rotation of the legs rather than wheels. To test, I coded the leg bot using the basic Linear Op-Mode program. There were issues with the motors disconnecting when hitting the ground as their wires physically disconnected. To solve this I took more REV extrusions and attached them perpendicular to the legs, adding space between the ground and the motor. Despite this the leg bot still proves to be unstable.

    Next Steps

    There is a chance we'll have to scrap the design and start with a different one. Leg drive is an interesting idea but actually working with it will probably not be feasible in the near future, especially if the game is a stacking game, since those rely on speed.

    SuperMan Wheel Fix

    SuperMan Wheel Fix By Jose

    Task: 3D model a fix for Superman using Fusion 360

    During the Discovery Faire Icarus' Superman wheel broke as the gears were skipping, rendering most robot articulations useless. For reference, Icarus was our robot for the 2019 World Championship and the Superman wheel is a mecanum wheel fixed to the base of the robot that, when extended, allows the robot to stand upright to a height of approximately 5 feet. The problem was the top gears were separating from each other and that caused them to also separate from the SuperMan gear. There is an easy fix for this, use a bar to join the motors together, effectively doing the same to the gears.

    This part was modeled by measuring the distance between the motors and the holes of the gearbox to hold the bar down. This ended in a bar 163.5mm long with holes spaced accordingly. This was simply extruded and the edges were made round. After the bar was printed it was proven to be tool long, the issue being the space between the motors is 62mm not 102.5mm.

    Next Steps

    We need to test the part on the Superman Wheel to see if its able to perform its articulations functionally.

    RIP Big Wheel

    RIP Big Wheel By Paul, Aaron, and Trey

    Task: Tear down BigWheel and harvest parts

    Big Wheel, Iron Reign’s first iteration of our Worlds competition robot Icarus, had been sitting outside in the tent for months and we needed parts for new robots - specifically for our Robot in 2 Days robot. Once the season reveal is released, Iron Reign plans to build a working robot within the weekend of the release. The need for parts was a pressing concern, so it was time for us to part with one of our oldest friends, BigWheel (Icarus, our worlds robot, was off the table because of sentimental value). So we went ahead and scrapped Big Wheel, taking the most important, valuable parts off first, like the bearing slides and arms, then we moved onto the chassis. We worked to break the robot down into parts that we could use on other bots, for this year’s challenge.

    We were able to get a lot of very useful parts off of big wheel, as most of the parts used on big wheel are the same parts that were used on Icarus, and this years challenge makes heavy use of the vertical reach and collapsibility of Icarus, and it makes sense to assume that many of the parts that were used on Icarus will come in handy this year. We hope to implement some of these parts to our Robot in 2 Days robot once the season reveal video is released.

    Aaron’s Super Cool Gripper That Works 100% Of The Time

    Aaron’s Super Cool Gripper That Works 100% Of The Time By Aaron

    Task: Prototyping a rolling gripper

    During the 2 day robot challenge, one of the gripper designs that we built on the first day was Aaron’s Super Cool Gripper That Works 100% Of The Time. While it did work most of the time, it was a bit too bulky to be implemented effectively in the two day period we had.

    The way it worked is by using the flexibility of the ninja flex rollers that we designed last year to slip over the stones, then because of the rubbery ninja flex material, griped on to the stone. Each roller was attached to a servo, allowing us to deposit the stone and rotate it into the orientation we desired.

    Next Steps

    Although the design isn’t near ready to be implemented, it did experiment with the idea of being able to rotate the stone while depositing. Not only that, but it was hinged at the very center on two axis of rotation, allowing for auto stabilization.

    Wheel Gripper

    Wheel Gripper By Jose and Trey

    Task: Design an intake for the stones based on wheels

    Initial Design: Rolling Intake

    The first idea we came up with for gripper designs during our Robot in 2 Days (Ri2D) challenge was a rolling intake with the wheels coming from the top and spinning to intake the stone. Since the wheels needed to spin they were placed on shafts which required two extrusions since the pillow bracket for them needs to be threaded on the ends of them to make this design compact.This design was rejected since we want to use the minimal amount of servos as possible and we came up with a more compact design that requires only one servo instead of two(one for each wheel).

    Final Design: Gripper Wheels

    This design involves two wheels attached to extrusions, one is idle and can't pivot while the other can be rotated in place by a servo. Once its grip was tested we saw that the wheels spinning was a problem. To fix this, the wheels where attached directly onto the extrusions this time and to enhance their grip, a rubber band was added to default the wheels' position as closed. A servo was added to the end of the main extrusion with a servo horn and polycarb beam to rotate the non-idle wheel back to release the stone in its grip. Finally, since drivers aren't perfect, a stabilizer made out of polycarb was placed in the middle of the gripper so it will always move towards the middle of the stones, in between the stubs. At first this was off by 90 degrees, but this was fixed shortly after.

    Next Steps

    We will have to implement this onto the Ri2D bot and run tests to compare this gripper against our others.

    Robot in Two Days - Day One

    Robot in Two Days - Day One By Karina, Bhanaviya, Aaron, Jose, Ben, Trey, Cooper, Sam, Sterling, Beau, Mahesh, and Shawn

    Task: Build prototype subsystems that pick up the stone elements

    This season Iron Reign decided to take on the robot-in-two-days challenge. Given that our team had never done this before, and we are primarily a team of underclassmen, we knew we would have to be organized in our efforts and that we would probably reuse old chassis.

    First thing right after the kickoff, the team convened back at our meeting spot to brainstorm ideas for robot designs which you can see above. Among the ideas we discussed was a "cupbot" of sorts, a lot like the designs seen for last years' challenge, except it would be shaped after the tops of the stones. This idea didn't pan out, however, because it would only be able to pick up the stones in the upright orientation, which is not something we can count on. We also had a sub-team prototype a parallel gripper, but it was an unsuccessful build in that it could not actually pick up stones. We did proceed further into the building phase with two designs for a gripper system: a rack-and-pinion gripper and a rolling gripper. One sub-team started on the rack-and-pinion gripper project, while another sub-team started on the rolling gripper project, both of which have separate articles which you can read about in our blog.

    Besides the gripper systems, we also discussed what kind of drive train we wanted to use this year. When we were at the kickoff, we noticed that Icarus's chassis was ideal for moving underneath the skybridges, and so we considered using this chassis for our robot in two days challenge. We also had the MiniMech chassis available for reuse. In the end, we proceeded with the mini mech chassis, which a subteam tuned on day one of the two day build, since it would be easier to add a gripper to the next day, and this earlier in the season, we were prioritizing gripper speed, not traveling speed between the two areas of the field.

    All work and no play? Of course not! Here at Iron Reign we like to have safe and wholesome fun as we work, which we had the opportunity to do when we caught an ice-cream truck driving around the neighborhood. Look at us having such a chill time!

    Next Steps

    To finish the challenge tomorrow, we will complete our gripper builds, choose our best design, and then mount it onto the mini mecanum chassis.

    Rack and Pinion Gripper

    Rack and Pinion Gripper By Cooper and Aaron

    Task: Build a gripper system for the 2019-2020 Skystone Challenge

    The rack-and-pinion gripper system is one of the 4 gripper systems we built this weekend for our Robot in 2 Days project. Since we’ve never used a rack-and-pinion system before, we realized that it would be a creative idea to start off the new season. Going for simplicity, we made a box such that we could fit 2 racks going in opposite directions, having the pinion in the middle. We constructed the racks with standard rev rails attached to the box with a rev standard linear slide piece and attached tetrix rack gears on the opposite side with double sided tape. Then the pinon was a rev standard gear attached to a rail on the back. The plan was such that when the pinion was turned the two grippers will move outwards and inwards to grasp the stones.

    After that, the actual grippers went through 2 iterations. The first was a straight, flat bladed polycarb sheet attached to the rack. We tried this, but it turned out that did not provide enough friction. The second iteration was a slight variation, where we bent the arms and added rubber foam to the end. This saw some success.

    Next Steps

    Overall, the system was very solid and worked reliably, and could be used in conjunction with a gimbal to make a well performing arm, but that didn't save it. For our weekend build, the rack-and-pinion is too incompatible with our chassis to be implemented in time - but as FrankenDroid (our new robot!) is not the final iteration of our competition robot, the rack-and-pinion gripper system will act as a prototype for any changes we choose to make to our gripper system as the season progresses.

    Parallel Gripper

    Parallel Gripper By Ben

    Task: Prototype a parallel gripper

    While there are many different solutions and gripper designs, one of the most common is the parallel gripper. The purpose of a parallel gripper is to grip objects, in our case stones, parallel to the object instead of at an angle. Since this was a rational idea to start off with, this was one of the gripper designs we experimented with in the duration of our Robot in 2 Days challenge.

    A parallel gripper would allow us to grip the stones more effectively, as it would grip with more surface area. Theoretically, these grippers work by having 4 bars/connectors which are all the same length. When they close, they close parallel.

    After building the gripper, we tested it with the stones. While it did an okay job at gripping, due to the fact that we didn't use any gripping material, it slipped a few times. Another issue we encountered was that it would be difficult to flip a stone if needed, which is a task other designs could perform.

    Next Steps

    If we decide to pursue the parallel gripper system, we would have to figure out a way to flip a stone so we could stack it, along with improving the grip.

    Robot in 2 Days - Day Two

    Robot in 2 Days - Day Two By Bhanaviya, Aaron, Cooper, Jose, Ben, and Paul

    Task: Finish Robot in 2 Days

    Since the reveal was released yesterday, Iron Reign embarked on a project to build a skystone-specific robot in 2 days. Yesterday was a planning ground, during which we began prototyping 4 robot grippers, and 2 chassis designs. With less than 24 hours to complete our robot, we started today off by getting build-specific decisions out of the way, so that we could narrow in on one robot design to code and work on.

    Of course, we couldn't settle on a decision without first finishing all 4 of our gripper designs. At the end, we had one gripper system that incorporated nylon gears, one that used regular wheels, one that used a rack-and-pinion system, and one that was a parallel gripper system. We decided to settle on the one using standard wheels that pivot to grip onto a skystone. While we haven't yet decided if this will be the same design we will work with in time for our first qualifier, it is a stable system for a robot in two days.

    As far as the chassis was concerned, we stuck to using Mini-Mech, our summer chassis project from the previous year. Since we added a control hub to Mini-Mech earlier in the week, all that had to be done was incorporate the gripper system onto its chassis, and program it to at the very least move and grip onto skystones. This was a lot of work that needed to be accomplished in 4 hours, but as full-fledged members of the Building A Robot The Night Before A Competition Club, working on a small time frame was nothing new to us. In the span of one practice, we finished implementing a working gripper system to Mini-Mech and coded it to move, grab and stack a skystone on the foundation top. We christened our creation FrankenDroid as a testament to this year's Star Wars-based theme and the fact that the robot was made from harvesting parts from our last years' robots, Big Wheel and Icarus.

    Next Steps

    While FrankenDroid's movements are far from being smooth, it is a start. Robot in 2 Days started off as a fun challenge for us - we did not expect to accomplish as much progress as we did in such a short span of time. As of now, we don't plan on using FrankenDroid as our competition robot - but it will be useful for drive-testing, and will serve as a prototype for any future iterations.

    Robot in 2 Days Grippers Comparison

    Robot in 2 Days Grippers Comparison By Jose and Bhanaviya

    Task: Analyze all our grippers from the Robot in 2 Days challenge

    During the making of our Ri2D we prototyped and designed several gripper designs to collect stones. These designs varied in the method of manipulating the stone, how many servos they required and how compact they are. All of these gripper designs have their own post describing them in detail, but this article summarizes all of these grippers as a way to help us with future gripper designs.

    1) Wheel Intake

    This idea was though of but never built since the design was to have wheels at about ground level to spin and therefore intake the block, the problem being that this would disrupt the other blocks in the quarry since it intaked the block from its short side.

    2) Wheel Gripper

    This design was to use wheels as grip since they have good friction, one set of wheels is stationary and the other set can open and close via a servo. Not compact, but required only one servo and had great grip on the stone. This was ultimately the design we ended up using in our final Robot in 2 Days bot, Frankendroid,since it was efficient in maneuvering and controlling stones and served as a good design for a quick, 2 days old robot.

    3) Aaron's Super Cool Gripper That Works 100% of The Time

    This design used 3-D printed wheels made of ninja flex that spun to intake the block, like the wheel gripper just not in a set position and it grabbed stones from above. This design was huge and required two servos as well as not having much grip.

    4) Rack and Pinion Gripper

    This design involved a rack and pinion closing some polycarbonate sheets to grip the stone. The polycarb sheets had foam for grip, but this was still not enough to even lift the stone, so an actual motor would be required.

    5) Parallel Gripper

    This design was to use a parallel grabber with some material for grip as an alternative to the rack and pinion design. Unfortunately, the parallel grabber wasn’t built correctly thus not parallel.

    Next Steps

    With all of our gripper designs from the Robot in 2 Days Challenge documented, we can now analyze how best we can improve these designs for future gripper iterations, as well as the potential of these designs to be combined to create an entirely new design. Currently, we are leaning towards using the gripper with Ninjaflex gears, which is the 3rd design in this article, once we've fine-tuned Frankendroid's design. We think a rolling intake will work well on our robot so this design is consistent with our idea to use the wheel gripper at present.

    P.A.U.L

    P.A.U.L By Aaron

    Task: Design a new intake system

    The Pivoting Accelerated User-friendly Locker

    After the end of the two day robot build, we had come up with two main gripper designs. One was consistent, however heavy and large, (Wheel Gripper) and one was lighter but wasn’t quite as versatile or controllable (Aaron's Super Cool gripper That Worked 100% of the Time). P.A.U.L (Pivoting Accelerated User-friendly Locker) is the best of both worlds. It’s made out of polycarb so it’s light and somewhat flexible, and its easily controlled by a servo.

    P.A.U.L was originally designed with a hole in the top where a servo could push a small polycarb rod straight down, pushing the stone out of the grasp of P.A.U.L. This might have worked, however we decided that it would most likely be more efficient and easily controllable if we switched to some sort of pivoting mechanism where one side of Paul could be controlled by a servo. The way that works is by fixing one side to an axle that is attached to a gear. That gear is then controlled by the servo on top of P.A.U.L.

    Next steps:

    In the future we plan to test different gear ratios, that way we could figure out the perfect ratio of torque to speed. We want a good amount of torque that way we can grip the stones tightly and securely so they don’t fall out while being jostled around on the field, however in this years challenge speed is going to be very important.

    Skystone Gripper Version 2

    Skystone Gripper Version 2 By Justin

    Task: Design an Intake Wheel

    The older iteration of the gripper wheel

    Last season, we designed a ninjaflex gripper for Icarus, our World championship robot. This season, we are experimenting with different intake designs. One of our intake designs is Aaron's Super Cool Gripper, which uses the ninjaflex gripper wheels we designed. The problem with this system is that the wheels are very large, and increase the total size of the intake system. In order to shrink the size of the intake, we need to design smaller wheels that will still be able to grip to the side of the stones. We also combined the design of this gripper with the Pivoting Accelerated User-Friendly Locker (P.A.U.L) so the new intake design uses the new gears on the combination of the existing gripper designs.

    Our design consists of a central hub with 8 short flaps attached around it. The design uses similar flaps to last season's design, but there is no ring to support them and the length is much shorter. The width was 2mm, with the circles at the end being 4mm in diameter. When we printed this design the flaps were not stiff enough to maintain grip on the stones. In our second iteration of the gripper wheel we increased the width of the flaps to 3mm, keeping the circle diameters 4mm. We did this to create stronger flaps that would provide more force against the sides of the stones. In addition to this, we also added curves on the edge between the flaps and the central hub to provide more support to the flaps. These two changes made the flaps much stiffer, so now there is much less force required to maintain grip on the stones.

    The newer version of the gripper wheel

    Next steps:

    We need to test this design on an actual intake system. We have a design that currently has last seasons gripper wheels on it. We need to swap the old grippers with our new design, and adjust the size of the gripper to accommodate the smaller wheels.

    TomBot CAD

    TomBot CAD By Ben

    Task: Design a concept for a circular chassis

    Concept of circular chassis

    A challenge we face this year is running into other robots. Last year, it was possible to easily get around other robots; however, this year it will be difficult to get around other robots, as there will be a lot more cross traffic in the building zone.

    Our solution to this is designing a circular chassis. This will allow us to brush other robots without getting caught. With this, we would be able to move quicker and accurately. We will construct a 17.5in circular chassis. It will be driven by 2 8-in wheels (ironton 8in. Solid Rubber Spoked Poly Wheel) with 2 sets of 4-60mm omni-directional wheels on the front and back of the robot for stabilization.

    Next Steps

    Our next steps are to begin construction of the circular chassis, which has now been named TomBot, after our coach's cat - Tom the Cat. We will begin construction of TomBot by creating a circular template, which will be 17.5in in diameter. We will then trace that shape onto a polycarbonate sheet and cut it out.

    Modeling Planetary Gears

    Modeling Planetary Gears By Paul

    Task: Modeling a planetary gearset for robot turntable

    External Gear Ring

    We decided on using a turntable on the robot to allow for maximum articulation and flexibility on our arm assembly. The gear ring pictured allows the turntable to be moved by a motor mounted on the turntable. This component was modeled in Fusion 360, using a gear generator to make the teeth and creating the mount holes and the mounting ring after creating the gear.

    The outer gear has 160 teeth, and the inner one has 20 teeth giving the two components a mechanical advantage ratio of 1:8. Both gears have a module of 1.5 mm, giving the gears enough definition to allow for precise movement while being coarse enough to print out on a 3d printer.

    Next Steps

    We need to print out the planetary gears and then mount the bevel gears to the turn-tables to ensure precision.

    Gripper Testing

    Gripper Testing By Paul and Justin

    Task: Test block gripper

    Here is us testing the gripper we designed to pick up the blocks in this years SkyStone challenge. This gripper combines the Pivoting Accelerated User-Friendly Locker, P.A.U.L, one of our earlier gripper designs, and Aaron's Super Cool Gripper, a design from our Robot in 2 Days Challenge. It has a backplate similar to that of P.A.U.L's but instead of polycarb flaps, it utilizes the smaller Ninjaflex gears (a smaller version of the gears on Aaron's Super Cool Gripper) that Justin modeled so it is essentially a combination of our best design ideas so far. It doesn't have a name yet so it will be called P.A.U.L Version 2. It was mostly effective in picking up the blocks, however we need more structural rigidity to ensure that the blocks don't rotate while being picked up.

    Next Steps

    Next steps include reinforcing the gripper frame, and mounting it to our prototyping robot. We also need to cut off the excess rev rail, to reduce weight and make it a little less bulky.

    Autonomous and TomBot Robot

    Autonomous and TomBot Robot By Karina, Jose, and Bhanaviya

    Task: Autonomous coding and TomBot progress

    DISD students have been blessed with a long weekend, which we plan to take full advantage of as our first scrimmage is closing in. Just as we started to test drive Frankendroid, we began to notice some faults with the robot. Lots of these were common errors, which can likely be attributed to the fact that we sped through the building of Frankendroid very quickly. For one, we left off a lot of pulleys on our belt and pulley system, which left the entire thing very loose and in need of tensioning. We also had an issue of bearings slipping out of their sockets for the gripper's elbow attachment. We promptly made sure that the axle and belt systems were set up properly.

    So far, much of the team's focus has been on building a robot, and we're just now getting around to coding. So besides tuning up Frankendroid, we took a look at our autonomous program. To start, we drew an auto path (version 1). Then, considering Iron Reign already has a large code base from all its years doing FTC, we copied the pre-existing minimech code to start the code for Frankendroid. In terms of the drive train, Frankendroid is pretty standard with four mecanums in a rectangular shape, and so the hardware map was the same. We had some null pointer exceptions due to calls to nonexistent motors, sensors, etc. Additionally, the motor behaviors were not working such that doing the controls to move forward and backwards actually made the robot strafe, and strafing commands made the robot rotate. All of this was fixed in code. Afterwards, we calibrated

    Lastly, we did build work on our work-in-progress TomBot. From wheel to wheel, the span was too great to fit within the polycarb frame we had previously cut. Everything (wheels, motors, extrusions) had to moved closer together on the main axle, and then centered. The two center extrusions intended to be a point of attachment to the polycarb frame extended past the perimeter of the frame, and so these had to shortened with a hacksaw.

    Next steps:

    Our code team is now gearing up for an intensive two weeks of writing and fine tuning code for the robot. Drivers will take this opportunity to practice driving and become familiar with controlling Frankendroid.

    Investing in a CNC Router

    Investing in a CNC Router By Bhanaviya

    Task: Invest in a CNC router using our grants from the previous season.

    Last year was a very successful season for Iron Reign, financially speaking. We earned around $11,000 in grants and funding from FIRST in Texas, Texas Workforce Commission and Mark Cuban, to name a few sponsors. In addition, this year we received a $200 Gobilda product grant. Most of this money was invested in last season's expenses. But as we found out over the course of our build season, our team incorporates a wide number of 3D-printed parts into our robot, and especially since we were recognized for our design process at the Houston World Championship through Innovate Award Finalist, our design process was one that we could further improve now that we've seen the level of competition at Worlds. Part of this includes using a variety of materials, as illustrated in previous seasons where we've used ice-cube trays and turkey-coolers into our robot's subsystems. So, what better way to improve our design process and spend our grant money than in investing in a CNC router?

    The router itself cost around $3000, and while this isn't cheap, it's a good investment since it now allows to cut our parts out of durable, inexpensive materials like aluminum and wood. So far, we have plans to use the router on the mounting under the turn-table of our robot and a logarithmic spiral that is being modeled to reduce the torque on our linear slide system. There's no end to how much this router can influence our overall design process. Our team is used to using Ninjaflex-printed parts but with the router, we can be more creative with the use of 3D-modeled parts on our robot.

    Next Steps

    Now, we can begin cutting the above-mentioned parts on the router once they've been fully modeled. We can also begin deciding what other parts need to be modeled that can easily be cut on the router.

    TomBot Suspension

    TomBot Suspension By Ben

    Task: Design a suspension for TomBot

    3 Different iterations of the passive suspension.

    We've decided to design a suspension for our circular chassis for one reason. Under the neutral bridge, there is a 15mm lip on the floor plate to connect the bridge support. Traveling over this plate can cause significant depreciation of the chassis and connected subsystems.

    We have currently made 3 different versions of possible prototypes. We will be using a passive suspension system. The suspension will be 3D printed in Nylon, as it is fairly strong and flexible. It is also shatter resistant, making ideal for withstanding large and nearly instantaneous forces.
    Our first design was a triangle, but we determined that it was too rigid and wouldn't flex enough to absorb the impact of running into the floor plate at high speed. The next design was an ellipse. An ellipse has the capacity to expand outward, making it ideal for absorbing significant impacts. The first ellipse, however, was too small and unable to support the weight of the robot and flex enough to absorb the impact. The second ellipse is taller, enabling it to withstand the weight of the robot and forces from driving onto the floor plate.

    The suspension will be attached to a 3D-printed wheel mount. This mount will have the capacity to slide vertically as the suspension absorbs any impact.

    Wheel mount with example suspension

    As of now, we haven't conducted actual trials on any of these prototypes. In the event we determine that Nylon is not ideal; we may look into designing a shock absorber made from NinjaFlex. NinjaFlex may be suitable due to its flexible nature. A part could be designed, such as a cylinder, with a thick hexagonal infill. This would allow it to flex while maintaining some rigidity.

    Next Steps

    After creating a few more different types of passive suspension systems, we will want to begin testing them. They will have to be attached to the robot and individually tested. We may also want to design a NinjaFlex suspension regardless of whether or not the Nylon suspension proves viable to see which is ideal.

    Ordering a Slip Ring

    Ordering a Slip Ring By Jose

    Task: Order a slip ring for the turn table

    In order to spin the turntable on TomBot we need to use a motor with a specific gear to make it spin and as a bonus we can use a slip ring to transfer power to it. Slip rings can prove to be useful since there would be no need to worry about wires getting tangled after the turntable spins a certain amount in the same direction and if done correctly, the turntable can be spun continuously, allowing for the very much necessary victory spins. The specific slip ring we need should have 6 wires, be able to handle 20 amps and 12 volts, and be at least 20mm in diameter. After some research on various sites, we found what we needed on aliexpress.com. This company features various slip rings for various purposes, which includes our "custom project" need. We ordered one at a hefty price, but if it works, its benefits will be worth it.

    Next Steps

    Once the slip ring arrives we can begin testing it on a test turntable to verify its viability on TomBot.

    Updating TomBot's model

    Updating TomBot's model By Bhanaviya and Ben

    Task: Update the model to plan TomBot's build

    With our first qualifier being less than a month away, Iron Reign embarked on an ambitious project to create a robot with a circular chassis named TomBot (which was, for reference, named after our coach's cat, Tom). Before we began the build of the robot, we planned out the chassis design in an earlier post on CAD. Now, with our chassis progress from last week, the model has been updated.

    The updated model still has the same base chassis design from the earlier model, but it now has extrusion bars above the chassis that were added in to the actual robot last week. It also has a turn table mounted on top of it to support our gripper arm and a gripper arm. As of now, the turn table hasn't been built yet but planning it out in the robot model will make it more efficient for us when we do start building.

    Next Steps

    With our robot model in progress, we can now plan out all our steps ahead of time in CAD so that we will make less mistakes on the physical build. We will be updating the model as the season progresses.

    Round Chassis Assembly

    Round Chassis Assembly By Justin, Trey, and Jose

    Task: Attatch Omni wheels to Round Chassis

    Today we finished assembling the round chassis for our circle robot, TomBot. The most important system we added was the omni wheels to the front and rear of the robot. Without the omni wheels, the robot would tilt like a seesaw around the central 2 big wheels. These omni wheels lightly touch the ground in the front and rear of the robot to keep the chassis parallel with the ground.

    The omni wheels were attached so that we have 3 wheels in the front and 3 in the rear. We used 3 wheels to give us more points of contact and more stability at high speeds. The wheels mounted to our new Go Bilda bearing mounts. The mounts have a central bearing with 2 mounting points that branch off of the bearing in a Y shape. The difficulty with this system of mounting the omni wheels is finding the correct height from the polycarb base to mount the bearings. The wheels should be as close as possible to the same height as the 2 big central wheels. The threads in the branches of the Y-shaped bearing mount are very short, which means that almost all the height adjustments need to be done with spacers and long screws. We used the longest screws we had, and after screwing them in to check if the height was right, we found that they were pretty close to what we needed. They still needed spacers to keep the screws from pushing up through the polycarb base, so we used the spacer heights to fine tune the height to get the omni wheels as even as possible with the big wheels. We found that exactly 1 and a half white plastic spacers looked pretty close to the height we needed.

    After assembling both sets of wheels, we placed the robot on the field and checked to see how much it tiled back and forth. We found that the 1 and a half spacers was the exact height we needed, as the robot doesn't tilt or wobble at all, and the big drive wheels still have plenty of traction on the field to drive the robot.

    These omni wheels allow us to use the chassis to test and work on our other subsystems, but we see some potential flaws in the wheels. The most significant flaw will occur at high speeds. The platform in the middle of the field has a steep edge to it, so driving over it at high speeds will cause those front omni wheels to take a lot of force. Since the mounting is rigid, that force will affect the whole robot and could either jam the robot up against the platform or cause the robot to hop and get shaken up a bit when it drives over.

    Next Steps:

    One of our modelers is working on 3d printing a suspension system to allow the omni wheels to retract under force. For testing purposes, and for our first qualifier, the rigid system should be fine, but later on the suspension will allow us to move at maximum speed. Our next step is to start assembling the rest of the robot to the chassis.

    Stub Gripper

    Stub Gripper By Jose

    Task: Building gripper iteration #7

    As our 8th gripper design we modeled a stub gripper, inspired by 7129’s Ri30H. Several of our previous grippers were designed with the intention of being mounted our scrimmage/Robot in 2 Days bot Frankendroid. This is our first gripper design modeled with the full intent of being mounted on our circular chassis bot, TomBot. In essence, this gripper has some bars to align the gripper with the stone and grabs it by one of its stubs. The benefits of this design is that it’s the most compact of all our grippers and it can grab a stone from either its long or short side. The drawbacks are that it requires great driver precision and whatever we use to grip the stub needs to have lots of friction to not lose grip since there are few points of contact.

    Next Steps:

    We will add this design to the others and decide which one is best to actually implement it on TomBot.

    3-Fingered Gripper

    3-Fingered Gripper By Jose and Aaron

    Task: 3D Model and build an 8th gripper design

    As our 8th gripper design we are trying out a compact design known as the 3-fingered gripper. This was 3-D modeled before being built as a proof of concept. The back of the gripper has two bars to orient the stone before being grabbed. One bar contacts the stone and the other does too as TomBot continues to approach it. The actual grip comes from a plate that can open and close via a servo. Once the design was modeled it proved to seem reliable, especially because of the two bars orienting the stone.

    Now for the fun part, actually contructing the gripper. REV extrusions were used for bars at the back since their width is ideal for the job. From here we used GoBilda parts such the plates and a hinge for the rest of the design. Optimizations were made for the attachment of the GoBilda plates since they aren't the exact length needed, and once another plate was attached to the first via a hinge we added a servo. This servo opens and closes the gripper(of course), to do so a polycarbonate bar was used to connect the servo and the hinged plate. Finally, we added grip material to the back bars and the gripping plate. By using a servo tester we were able to test its functionality. Tests proved that grabbing the stone is really easy, but the grip could use work.

    Next Steps

    Compared to the other gripper designs this one seems to work best so we will optimize it some more add it onto TomBot.

    Gripper Iterations Summary

    Gripper Iterations Summary By Bhanaviya

    Task: Go over our 9 gripper iterations

    This season, we experimented with 9 gripper models - both for our robot in three days project and for our competition bot. While we do not plan on using all 9 of these models, they allowed us to effectively implement the engineering process within our build season. Experimenting with each gripper helped us to identify the potential of each design as well as how two individual designs could be combined to create a more efficient one. Each of these designs has its own article but this is just a summary of all of our gripper designs so far.

    1)Wheel Gripper

    This was one of our first designs and was intended mainly for our robot in 3 days bot. This was also the very first gripper we actually mounted onto our robot. It started out as a rolling intake but then was modified so that the standard rev wheels on the gripper could swivel to grab the skystones.

    2) Parallel gripper

    This gripper functions with two rev extrusion bars moving inwards parallel to a stone to grasp it. We never actually implemented this design into any of our robots but it allowed us to understand that for it to work it would need to be mounted in front of a more solid back-plate. We later used a polycarb back-plate for a couple of our later designs.

    3) Rack and Pinion Gripper

    We've never used rack and pinions in our subsystems before so this was also a relatively new idea to test. We used polycarb grips to test out this gripper. While this gripper worked, it was also rather slow to function and we needed a faster gripper. While we didn't use these, we used the polycarb grips for our later gripper design.

    4) Aaron's Super Cool Gripper That Works 100% Of The Time

    This gripper has two ninja flex grippers to swivel to grab skystones. This was the second gripper that was used on Frankendroid after the wheel gripper. It also has a polycarb back-plate for stability.

    5) Pivoting Accelerated User-Friendly Locker

    This gripper, P.A.U.L for short, is modified version of the rack and pinion gripper. It has the polycarb grips but instead of a rack and pinion system it has two servos that control two gears mounted on a polycarb back-plate. This gripper was also mounted on Frankendroid. This design was later modified to create a more improved version.

    6) P.A.U.L Version 2

    Speaking of improved versions, this gripper replaced the polycarb grips on Gripper #4 with ninjaflex gears. It combines design #4 and #5 to create a more effective sub-system as it had more space to rotate to grip around the blocks. (this design does not have one single post but two - one about its testing and one about modelling the ninjaflex gears).

    7) 3-Finger Gripper

    This gripper has a plate attached to a servo such that the plate can move vertically to close down on the stone, with two extrusion bars on the back of the gripper to support the stone as it is being lifted. This is one of our newer designs but it has been tested, and we plan to mount it onto TomBot to determine its precision.

    8) Stub Gripper

    The stub gripper grabs onto mainly the stubs of the skystone. This gripper hasn't been built yet either but it has been modeled on Fusion 360. The effectiveness (and challenge) of this gripper relies on it being able to pick up a stone with minimal contact to the stone itself.

    9) Cylindrical Gripper

    The cylindrical gripper is being modelled on Fusion 360. It comprises of a c-shaped tube rotating and closing in around the stone. While we don't have any immediate plans to use it, its an idea that has potential and we plan to experiment with it once we've narrowed down the most efficient gripper ideas for the TomBot.

    Next Steps

    Now that we have analyzed all of our gripper designs so far, it will be easier for us to streamline which design will be the best to implement on the robot. Right now, we are leaning towards the 3-finger gripper since it's compact, easy to function, and is the only gripper made with the specific intention of being implemented on TomBot.

    CNC Turntable Mounts

    CNC Turntable Mounts By Justin

    Task: Model and CNC way to mount the turntable to the chassis

    Today we worked on creating a 3d model for a CNC cut part to mount the turntable to the chassis. Since the turntable already has bolts sticking out of the bottom, we decided to use those as mounting points for our part. The most efficient solution to mounting the turntable is to cut a plate that attaches to the turntable bolts and has points to attach legs that will attach to the polycarb base. For convenience, the legs will be vertical tapped rev rails.

    Our first decision was deciding where to mount this plate. We determined that there should be 2 plates that attach to opposite sides of the robot. The plates would be curved and attach underneath the nylon gear. Each plate would attach to the turntable using 3 of the turntable's bolts, which uses all 6 of the bolts for mounting. Next, we needed to create bolt holes for the legs to attach to. In order to be able to drop bolts through the holes, this plate must extend slightly outside the turntable, because the plate will be flush with the nylon gear. We created a common radius from the center of the turntable where these holes will be placed, so that there is enough distance between the holes and the nylon gear. These holes would have to be placed so that the attached legs aren't blocked off by the rev rail already on the chassis. To fix this, we decided to put 7 total holes on each plate to mount the legs, all equally spaced around a common section of the circumference. This way we can play around with the mounting points, since we only need about 3 for each plate.

    Next we decided whether to mount the plates to the front and rear, or the left and right of the turntable. We counted up how many mounting points were available for each orientation and decided that the front and back mounting would give us a stronger attachment. The front and back are also where the turntable will want to lift up and push down under heavy loads, so it makes sense to mount at those points.

    During mounting, we found out that the spaces between the turntable mounting holes and the leg mounting holes at 3 points on each plate were too small to attach a REV rail leg. This is because the bolt from the turntable prevents the REV rail from being flush with the plate. To fix this, we used longer bolts on the turntable and used the revrail legs as both supports for the table and nuts to keep the plate onto the nylon gear/turntable.

    Next Steps:

    Our next step is to mount the legs to the plate, the plate to the turntable, and the whole thing to the robot. We need to measure out what length of rev rail legs we need to allow the turntable to spin freely without interfering with the chassis. We then need to mark and drill holes in the polycarb base to attach the whole subsystem. These mounting plates still need to be tested with the full capacity of the robot. Any issues should only come from the rev rail legs, which can later be replaced with a more custom solution.

    Logarithmic Spiral Design

    Logarithmic Spiral Design By Ben

    Task: Design a system that could linearly reduce torque.

    Since last season, we have conducted a significant amount of experimentation on our elbow and slide mechanism. We are using a similar design because we have prior knowledge on how to construct and maintain the subsystem; however, our slide this year is larger due to our desire to stack the stones higher. Although our elbow could lift the entire slide, we want to reduce the strain on the system by designing a component that would apply torque to the slide. Reduced strain will decrease the maintenance we will have to perform and will also increase the efficiency of the elbow by assisting it. The part would be attached with a bungee from the part to another part also on the turntable a few inches away.

    We decided to use a logarithmic spiral (r=ae^(bθ)) because it would reduce the torque exerted on the elbow linearly. To create this spiral in Fusion360, we had to write a script because there is no native spiral/equation builder. The code can be seen below and was adapted from code that can be found here. Once the code was executed, it created a sketch of the spiral, which you then had to spline into a line. Since we wanted the spiral to be tangent to the gear it would be attached to, we imported a model of the gear and aligned it with the spiral to find the optimal a & b values. Another requirement was that the spiral must be under 3 in and preferably 2.75 in to allow for space between the elbow and turntable plate. These values were a = 0.2 & b = 0.6, which were determined through various trials.

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    import adsk.core, adsk.fusion, adsk.cam, traceback, math
    
    def run(context):
        ui = None
        try:
            app = adsk.core.Application.get()
            des = adsk.fusion.Design.cast(app.activeProduct)
            root = des.rootComponent
    
            # Create a new sketch.
            sk = root.sketches.add(root.xYConstructionPlane)
    
            # Create a series of points along the spiral using the spiral equation.
            pnts = adsk.core.ObjectCollection.create()
            numTurns = 5
            pointsPerTurn = 20
            distanceBetweenTurns = 5
            theta = 0
            offset = 5
            a = 0.2 #aVal
            b = 0.6 #bVal
            for i in range(pointsPerTurn * numTurns + 1):
                r = a * math.exp(b * theta) #Definition of a logarithmic spiral
                x = r * math.cos(theta)
                y = r * math.sin(theta)
                pnts.add(adsk.core.Point3D.create(x,y,0))
    
                theta += (math.pi*2) / pointsPerTurn
    
            sk.sketchCurves.sketchFittedSplines.add(pnts)
            ui  = app.userInterface
            ui.messageBox('Spiral Done')
    
        except:
            if ui:
                ui.messageBox('Failed:\n{}'.format(traceback.format_exc()))
    

    Final design over original spiral

    Once we had the design, we printed it onto paper through the Fusion draw tool. We then confirmed that the holes aligned with the gear.

    After confirming the design aligned, we began preparing it to be machined on our CNC. For this part we went with 1/8in aluminum because it is both durable and inexpensive. It will also withstand the forces that will be exerted on the part.

    The finished part came out nicely with a few tabs that had to be removed. The part fit correctly and was successfully attached to the elbow and gear.

    Next Steps

    Our next steps will be to machine the part again, creating an identical copy, and printing the same design out of nylon, but taller. The nylon component will be sandwiched between the aluminum pieces and will have a cutout that will connect a bungee cord to it. We also have to design a part that will connect the bungee to the other side of the turntable. After introducing the bungee, we will have to conduct trials on the elasticity to determine the best bungee length or composition. These are necessary because we don’t want to apply too much force, restricting the elbow from lowering, yet we want to apply enough force to considerably assist the elbow when lifting.

    Morph Chart

    Morph Chart By Bhanaviya

    Task: Create a morph chart to analyze all our designs so far in this season.

    Iron Reign has seen several iterations of several subsystems over this past build season. With our first qualifier being 2 days away, its finally time to come full circle and identify the different iterations of different subsystems coming together. To do this, our team used a morph chart. A morph chart shows the various subsystems of our 2 robots in this system - our robot in 2 days bot Frankendroid and our competition bot TomBot.

    The left axis showcases the different subsystems like gripper designs for both robots, chassis designs and progressions, and extension mediums. A morph chart is often used by professional engineers to document the cyclical nature of choosing and moving through various designs. So far, Iron Reign has been through 9 types of gripper designs, 2 chassis designs, 2 linear slides systems differing in lengths and a third one incorporating the logarithmic spiral described in an earlier post.

    Across each row, alternative designs for each subsystem have also been depicted. As of now, our current robot has a circular chassis as shown in the second design in the fourth row, a flat gripper system as depicted in the first column of the third row, and a linear slide system supported by a logarithmic spiral in the fifth column of the fifth row.

    Next Steps

    Placing all of our designs in one chart like this allows us to see how iterative our design process has been, and how much of an influence each design has had on another. With all of our designs so far placed in the morph chart, our next step is to continue to update the chart after our first qualifier so that we can have a pictorial summary of our entire build season for reference.

    Night Before Competition Build

    Night Before Competition Build By Aaron, Cooper, and Trey

    Task: Transform a mass of metal into a functional something in the span of one night in time for the qualifier tomorrow.

    Twas the night before competition and the robot was most definitely not competition ready. This is what usually happens, but once again we found ourselves scrambling around to get everything together before the end of the night. We ended up mounting the gripper, setting up the belts, making hooks for the foundation and of course a whole lot of minor fixes and adjustments.

    Mounting the gripper was actually something that we completely finished at competition, however the night before we decided the previous mount would work. Although ingenious, the previous mount would have been to wiggly and not reliable. We ended up opting for a less simple design, however more stable and efficient. With the design we came up with, we realized we still wanted a degree of rotation on the x axis so that when stacking, gravity would automatically align the stone to the rest of the presumed tower. We achieved this in the simplest way by having two c shaped bars connected by only one screw in the middle on either side, allowing it to move back and forth.

    The belt was probably the most difficult part. What we needed to mount the belt was a piece that went up and over the rest of the slide then back down the other side, in order to have an attachment point for the end of the belt. This piece would be attached to the back of the top slide, and would be the highest point of the robot, which presented its own challenge. We needed this part of the robot to be able to fit under the bridges, and couldn’t make it go over not even just a bit or it would get caught and ruin the whole game. We tried constructing this piece by drilling a line of holes into the section of the metal we wanted to bend, making it weak enough to bend, however that ended up in just breaking the metal. We then decided it would be much stronger if we used the already bent L channel and just used two of them attached opposite ways.

    The hooks for the foundation were pretty last minute and ended up not being very functional. This resulted in us immediately changing them when we got back from competition. The hooks we had at competition were two polycarb L shaped pieces the simply would rotate downward. We mounted them onto and axle driving by a core hex motor. The main issue what that they didn’t have enough contact area to the foundation and we couldn’t effectively move it. We also realized that if we wanted to efficiently move the foundation, we would need to be able to rotate it, which would require contact from the back as well.

    Next Steps

    With the robot completely (mostly) built for our first qualifier of the season tomorrow, our next concern is driver-practice. As of now, we have no drive practice so this is something which we will be trying out for the first time this season with TomBot tomorrow on the practice fields.

    Build Post-Mortem

    Build Post-Mortem By Bhanaviya and Aaron

    Task: Begin analyzing long-term build improvements

    Moving on from the Allen qualifier, there are a couple issues we need to fix. Aside from the usual wear and tear a robot experiences in it’s relatively short life-span, there are some specific opportunities we have for optimal robot performance which we hope to act upon.

    First, our grippers don’t have enough degrees of freedom to rotate fully. Being able to rotate gives the ability to pick up stones from any orientation. As such, we plan to create a swivel mount which will allow them to turn enough to grab and place skystones.

    Second, our grippers don’t have the best grip potential, so we hope to find more “grabby” materials to improve their grip. This can be anything from 3D-printed parts to some oven-mitts, which we have been considering using for a while now.

    Third, our robot moves slower than we’d like it to and the turntable lacks control when turning. Part of this comes with having motors and gears with a “good enough” amount of torque to give us more control or vice versa for speed. As such, we hope to calculate the exact amount of rotational force acting upon the robot to determine how to improve its speed or control in functioning. This can be as simple as finding new motors.

    Finally, we want to build a completely custom-built robot. Other than being a pretty cool flex, customizing our parts allows us to have a greater degree of control on the functionality of our robot subsystems, as demonstrated with the logarithmic spiral we printed to reduce stress on the elbow. Part of having a custom-built robot means documenting all our current parts in a bill of materials and identifying which of these parts we can manufacture in our new CNC Mill. Although we know this isn’t a goal we can accomplish before our second qualifier on the 11th, it is one we can have done hopefully before regionals.

    Next Steps:

    This time, we want to test our build improvements more often since testing is one thing we haven’t been too keen on during preparation. This is mainly a long-term list of goals we want to focus on but other smaller improvements will be detailed per usual in blog posts.

    Swivel Mount

    Swivel Mount By Aaron

    Task: Design a swivel mount to improve the degrees of freedom on the gripper

    After the recent competition, we realized that a good way to increase precision would be to add, of course, another axis of rotation. This was the most efficient way to be more precise and pick up a stone from all angles. With a swivel mount, the gripper would be able to rotate on the y axis, via a servo. We already have a simple mount that rotates on the x axis, not motor driven, that utilizes gravity to automatically align the stone with the tower in stacking it, however we realized that a lot of time during teleop was wasting in trying to achieve the right angle at which to grip the stones.

    The way we achieve a swivel mount is by mounting a servo facing downward directly onto the gripper, and yes, direct drive is never really a great idea and maybe the easiest thing to do right at that moment was to just mount it directly to the gripper but a swivel mount is a more universal solution for when the gripper needs to turn a certain angle. The only problem is that we also use a servo to actuate the gripper arm mechanism, meaning that we will have a wire that will limit the rotation of the gripper itself. We could get an itty bitty slip ring if we really wanted to, but in reality we don’t see ourselves actually needing the full three hundred sixty degrees of motion.

    Next Steps

    Now that we have a swivel mount, our next step is to test, test, and maybe even test it. We don't know what degree of control we have on the swivel mount so testing it out will help us analyze what changes need to be made on our gripper.

    Finger Gripper Version 2

    Finger Gripper Version 2 By Jose

    Task: Design a swivel and add ninjaflex parts to improve the finger gripper

    From what we learned at the Allen Qualifier the gripper needs some major improvements before it will work at its max performance. The first change that needs to be made is replacing the current grip material with some more flexible material, such as ninja flex which we have used before as a gripping material. The print we have on the gripper is large but when the gripper closes its flexibility allows for it to grip the stone much better.

    The second improvement was to add a swivel to the entire gripper. This was done by adding some REV beams to the top of the gripper and attaching those beams to a servo. After some experimenting with the placement of the new, larger gripper we found a place that gives it over 180 degrees for motion. This will prove to be useful as not even the turntable will have to be turned to grab a stone, increasing the amount of stones we can score.

    Next Steps

    We need to implement some code that will allow a second driver to control the swivel as well as add some articulations now that we have a new degree of freedom. Additionally, we will need to add a damper to the oscillatory motion of the whole subsystem while in action.

    Adding to TomBot model

    Adding to TomBot model By Ben

    Task: Update the current robot model

    Prior to updating the model, the model purely consisted of the chassis and the primitive turntable. Since then, both the turntable and chassis have been updated to reflect the current state of the robot, along with the addition of the elbow and slide. The elbow component consists of GoBILDA shafts, gears, and connectors, along with the logarithmic spiral. The elbow can be seen below.

    The next addition is the linear slide. This consists of different slide components which were taken from a model constructed in PTC Creo and a linear slide gear mount. The slide can be seen below.

    With this updated model, it will be much easier to develop strategies based on different articulations since we can now accurately visualize the robot. The updated model also allows coders to better visualize the robot, increasing programming efficiency.

    Next Steps

    As you can see from the model above, there is no gripper. Our next steps will be to model the gripper which is to be constructed and attached to the next version of the robot.

    Finger Gripper Version 3 CAD

    Finger Gripper Version 3 CAD By Jose

    Task: Design a more comapct and efficient gripper design

    This version of the finger gripper is going to be mostly custom made to make it as simple and as compact as possible. This is just the CAD model of the actual design and we plan to update a little more before we can actually make the physical change on the actual gripper. The design remains the same but the gripper now has a new addition, a capstone deployer. The idea is to have the capstone preloaded on the gripper and have a mini servo drop it on the last stone we are placing. The design of this capstone is in another blog post, but the idea is to make it as small as possible to not make the gripper much larger.

    Next Steps

    We need to make this design perfect before printing, once that is done we can do so and begin its implementation on the robot.

    Bill of Materials

    Bill of Materials By Bhanaviya, Trey, and Jose

    Task: Create a list of parts needed for the new robot

    To determine all the materials we need for the new robot, we started a Bill of Materials. To do this, we first analyzed TomBot sub-system by sub-system. We determined the parts used for each sub-system and placed it into a spreadsheet. Upon doing this, we needed to get each part's exact measurements so that we could save time when trying to cut the new parts. Additionally, we needed the quantity of each part as well as which manufacturer it was from. Something new about the new robot is that we hope to have a completely CNC-ed bot with as many custom parts as we can incorporate. Using a good number of custom parts will allow us to be more creative with the robot design itself since everything we add to it will be custom-printed. This will also allow us to improve our engineering process as we iterate through multiple different versions of a part. This was critical because at the end of the day, the task was to build a better version of TomBot but using, more or less, the same parts.

    Next Steps

    We will update the bill as we iterate through more parts. As of now, TomBot has several build issues that will be discussed in our post-mortem posts. Part of rectifying these issues includes ordering/printing more parts and editing the bill accordingly.

    Capstone Version 3

    Capstone Version 3 By Jose

    Task: Design a minimalistic capstone that can be deployed by the stone gripper

    This version of our capstone is to be 3D modeled and printed as well as be as compact as possible to be deployed by the gripper. The basic idea is that the capstone is flat while meeting the minimum size for length and width. The capstone will be an 'I' shape to fit around the nubs of a stone. From here a small beam will be attached on the hole which is extended out of the 'I' as shown above. This will be 3 inches long, making this capstone technically legal. This capstone is small enough to allow another capstone to be placed on top if needed.

    Next Steps

    We need to fully 3D model this capstone and change the bottom of the gripper so it can be deployed easily.

    Capstone Iterations

    Capstone Iterations By Bhanaviya

    Task: Go over all 3 of our capstone iterations

    So far, we have experimented with 3 capstone models. While we do not intend to use all 3 of these models, they allowed us to effectively implement the engineering process on our robot. Although the capstone isn't physically a part of a robot, its various iterations influence the model of the gripper being used since the ideal gripper must be able to pick up both the skystones and the capstones over the duration of a match. As such, this article analyzes these designs to help us determine which gripper is best for use at our next qualifier on January 11.

    1) Aaron's Super Cool Capstone That Works 100% Of The Time

    The capstone that we made and used at the competition wasn’t the prettiest thing, but it had heart, and was destined for greatness. It was constructed from prototyping wire and duct tape. The basic design was a ring with a spherical top over it in order to not fall off when dropped onto the tower. It also had four large screws on each side in order to weigh down the capstone so as to not slip or slide off the tower when dropped. While this capstone was firm in structure, it requires a lot of precision to be placed on top of the stone itself. Since this year's game is very speed-based, a precision-based capstone is not the most effective.

    2) Jose's Super Cool Capstone That Works 100% Of The Time

    The next capstone was custom-designed and printed at our very own Robo Dojo. Simply put, it is a much flatter, rather 2D version of a skystone. It had two large rectangles in the center to drop onto both the stubs of a stone on a tower. It also has a small rectangular tab at its edge which will allow the gripper to pick it up. But given its shape, an issue would be the ability of our gripper to pick it up and drop it onto the tower without tipping over the entire stack. Once again, while it was destined for greatness, it was not built for the unrelenting force that is time and it would take too much control and seconds to be capped onto a tower.

    3) The I-shaped Capstone That Works 100% Of The Time

    Our latest capstone design is also custom-designed and 3D-printed out of nylon. Structure-wise, it is a flat 'I'. But in terms of capacity, it is the easiest of our capstone models to be picked by the gripper and drop onto the skystone. This capstone aims not to be dropped on the stubs of the stone but rather in in the middle of the capstone where it requires less precision to be dropped and is less likely to fall. It comes with a small tab similar to the one on our second capstone which allows the gripper to pick it up with ease.

    Next Steps

    Now that we have analyzed all of our capstone designs so far, it will be easier for us to streamline which design will be the best to implement on the robot. Right now, we are leaning towards the I-shaped capstone since it's less precision-based, smaller, and easier to be picked up by our current finger-gripper.

    Finger Gripper Version 4 CAD

    Finger Gripper Version 4 CAD By Jose

    Task: CAD a slightly different capstone version to improve upon v3's issues

    On this minor update to our flat gripper design a dropper for the latest capstone was added. Our capstone design (which can be seen here: E-65 ) is minimalistic to allow it to be placed on the gripper and only deployed until the last stone in the match is placed to cap it. The basic idea for this capstone dropper is to have a bar which has the number 6832 on it to match the 6832 indent on the capstone. This dropper will keep the capstone in place until the gripper is opened to beyond 45 degrees. To allow the gripper to actually close, a triangle was cut off the dropper as seen in the image above. Here is the final design:

    Next Steps

    Once the design is finalized(there may be a 5th version if a change is needed) this will be 3D printed and will replace the current gripper on the robot.

    Materials Test Planning

    Materials Test Planning By Bhanaviya

    Task: Create a system to test our materials to better understand their grip potential

    Here at Iron Reign, we're used to using off-the-shelf materials for our robot. For this season, these include silicon oven-mitts and ice-cube trays, since we find these grip skystones pretty well. However, we need to do a thorough investigation of these materials before we can determine their efficacy on the robot.

    Specifically, we plan to implement these parts on the underside of our gripper, to improve its friction when in contact with a stone. Our current gripper uses parts of ninjaflex gears but these aren't the most effective in picking up stones quickly. This is a bit of a concern since this year's game is so speed-based. As such, the time has come for us to replace the material on our gripper. However, before we can decide which material would have the best grip, we need to test them to determine their on-robot properties. To do this, we will implement a slip test as shown below.

    The main thing that we want to test is the amount of energy they have while rotating and then the amount of energy they lose upon collision. We plan to test this through the coefficient of friction of the mitts. Simply put, we will place the skystone on top of the of the silicon oven-mitts/ice-cube trays and will tape down the material being tested on a flat surface. Then, we will lift the surface and using simple inverse trigonometric properties, we will calculate theta, the angle at which the stone begins to slip from the material. The bigger the angle, the higher the friction coefficient of the material, which equates to it having better grip.

    Next Steps

    With our testing planned out, we will next begin documenting the angle at which the skystone slips from each type of material. The calculations from the actual testing, including the equation we used, will be inputted into a separate post.

    Testing Friction Coefficient

    Testing Friction Coefficient By Bhanaviya

    Task: Measure the coefficient of friction of our potential gripper materials

    We want to measure various constants of materials on our robot. These materials serve to improve the grip on our gripper. But before we can decide which material will be most effective on our gripper, we need to find the friction coefficient of these materials through a slip test. The slip test is detailed in a separate post in E-67. This article serves mainly to show the specific friction coefficient produced by each material in the slip test.

    To measure the coefficient of friction, we first had to simplify an equation to determine what values to measure.

    Based on these calculations, we realized that the best way to calculate friction coefficient would be by deriving the angle of incline at which the skystone begins to slip from the material, which is placed on a flat wooden board. If we take the length of the side of the board being lifted to be the hypotenuse, and the height at which the board is being lifted to be height, then theta, the angle of incline, is arcsin. As the board is lifted, the stone begins to experience slippage and the angle at which it slides off the material being tested will be marked as its friction coefficient. The higher this value, the more grip the material has.

    The materials we will be testing are a green silicon oven-mitt with hexagonal ridges, a red silicon oven mitt with small rectangular ridges, and an ice-cube tray with cubical ridges. The wooden board on which this the materials and skystone are being placed on has a length and width of 23.5 inches. This will be the hypotenuse for the purposes of this test.

    Green Silicon Oven-Mitt

    When the wooden board was lifted with this material on top of it, it took a height of 10.3 inches before the stone began to slip. Using arcsin, the angle of incline for this material was 26 degrees. By using the equation above, we can find that the coefficient of friction is tan(26) which 0.48.

    Red Silicon Oven-Mitt

    When this material was tested, the board had to be lifted 13.7 inches before the stone began to slip. The angle of incline for this material was 35 degrees so the coefficient of friction is tan(35) which is 0.7. Since this value is higher than the green oven-mitt, the red oven-mitt has the better grip.

    Ice-Cube Tray

    The board reached a height of 12.2 inches when the stone began to slip from the ice-cube tray. The friction coefficient for this material was 32 degrees, and its coefficient of friction was hence 0.66, putting it above the green oven-mitt, and slightly below the red oven-mitt in grip.

    Next Steps

    The material with the largest friction coefficient will be attached to the gripper on the robot. Since the red silicon oven-mitt had the largest angle of incline, this will be the material we will use in the next iteration of our gripper.

    Sliding Foundation Grabber

    Sliding Foundation Grabber By Trey, Jose, and Aaron

    Task: Design and create a more efficient and compact foundation grabber

    Moving the foundation throughout a match is an important part of the overall gameplay of a team. The builders on Iron Reign went through many different designs before reaching the one we have now. Early in the season, we simply settled for a simple hook attached to a servo on the front of the robot; however, this proved to be quite unstable. The foundation wobbled back and forth when the robot was in control of it and with this in mind, we went back to the drawing board. The second design we had in mind was a lot like the first but with two large, unwieldy, polycarbonate hooks that spanned at least four inches. These were often great at keeping a stable grasp on the foundation but they were made out of polycarbonate and flexed quite a bit and also were just too big in general.

    The design we have now consists of a sliding metal door that is controlled by a servo with a spool of string on it. The metal door models something of a guillotine that lifts to let the edge of the foundation in and then drops to secure it. This door, with its wide bottom, provides a great amount of stability and the base that its mounted to makes it so that the force inflicted by the foundation is passed into the base and then into the drivetrain. The fact that the grabber is not only attached to the servo but also fixed to the robot makes it so that the moving parts are less likely to snap or slip. And all of the components fit into a small space that should not be too much of an obstruction to the arm. Overall, this foundation grabber checks the boxes that the previous ones did not, It's compact, controls the foundation well, and definitely won't bend or snap.

    Next Steps

    No design for any part on any robot is perfect and this grabber is no different. The spool and string that is used to control the door is most likely temporary because there is probably a better way to open and close the door of the grabber. However, one thing that can and will be improved upon with the spool and string is that if provided with an upward force, the door of the grabber will open. This can be fixed by making the string on the spool continuous which will prevent this from happening by providing an opposite force, holding the door in place.

    Finger Gripper Version 2.1

    Finger Gripper Version 2.1 By Bhanaviya and Aaron

    Task: Replace the ninjalfex gears on the finger-gripper with a material with more grip.

    The finger gripper is the pinnacle of technological evolution, with class, durability and most importantly, metal. But it does lack one defining feature - grip. Currently, the underside of the metal plate on the gripper has parts from our ninjaflex gears used in Relic Recovery, and while it has all the refinement of an almost 3-year old part, it could be improved. Introducing the Finger Gripper 2.1, brought to you by Iron Reign. (although this change is being made after version 3 and 4 of our gripper, it is listed as 2.1 since 3 and 4 have only been designed in CAD and we are yet to translate this into a physical change.)

    On the matter of choosing which material to replace the ninjaflex gears with, we had 3 options to chose from. The first was a red silicon oven-mitt with rectangular ridges, a green silicon oven-mitt with hexagonal ridges, and an ice-cube tray with cubical ridges. To determine which material would work best, we put them a slip test, which can be found in E-69 . Of the 3 materials we tested, the red silicon oven-mitt had the largest friction coefficient. This makes sense, considering it had the sharpest ridges of the three, hence allowing it to grip the stone better. Hence, we replaced the material under our current finger gripper with a small piece from the red silicon oven-mitt. Although changing the material underneath the gripper seems like a minor design change, the improved grip will allow us to rely less on precision and more on speed during the actual game.

    Next Steps

    Next we will test the actual gripper to see if the material lives up to its results from the slip test. Once version 3 and version 4 of the finger gripper have been fully modeled we will print these designs and modify the gripper accordingly.

    Assembling the Turntable Bevel Gears for a REV Motor

    Assembling the Turntable Bevel Gears for a REV Motor By Trey and Justin

    Task: Assemble the bevel gears to the turntable to fit a rev motor

    Today we assembled a second version of our bevel gear assembly for the turntable. Our previous design used an Andymark motor, which was very fast but couldn't provide enough torque for precise movement. The custom geared REV motors allow us to power the turntable with our desired torque. This is further explained in our Calculating Torque at the Turntable post dated 2020-01-01 . The Gobilda motor mount was designed to fit motors wit 6 evenly spaced mounting holes, while the new REV motors have 8. We decided that the most efficient solution was to mount a rev rail motor mount to the Gobilda channel. First we had to make sure the holes lined up and the motor shaft was centered in the channel; the holes lined up perfectly and centered the shaft in the channel. The sides of the motor mount were too wide and had to be cut to allow the mount to slide in the channel enough to line up the mounting holes. Due to the apparent standardization of mounting holes, we could easily mount our new motor to the gears. The rest of the assembly was just following the Gobilda instructions for assembling the bevel gears and bearings. We were ready mount the new motor assembly to the turntable.

    Next Steps

    Next we will remove the old motor assembly and replace it with the new one. We also need to test the strength of the mounting plate under the load of the turntable. We should also use the time with the turntable off to inspect the nylon gears for any wear.

    Calculating Torque at the Elbow

    Calculating Torque at the Elbow By Bhanaviya

    Task: Design an equation to model the torque at the elbow linearly

    In order to maximize our robot performance, we need to be able to use motors and gears with the most ideal gear ratios. This means having the right amount of torque to produce the most efficient performance out of our robot arm. As the arm extends, there is quite a bit of torque on the elbow. We want to model this torque as a function which will allow us to better analyze how much rotational force is being exerted on the elbow and whether the gear ratio of the gears at the elbow could be improved by using a different gear set.

    The torque at the elbow is a dynamic variable that changes as the arm is extended further and further. As such, we decided to model this equation as a function. Torque is generally T = Frsin(theta). F is force which can be derived by multiplying the mass of the arm (m) with g, the acceleration due to gravity. g can be otherwise defined as g = G, the universal gravitational constant, * (m/r * r). r is the distance from the center of mass of the arm when fully retracted to the axis of rotation, which is, in this case, the elbow. This value can be defined by 170.4 meters. However, since the center of mass changes as the arm extends, r is not a constant and as such can be modeled as C + x, where C is the constant for the center of mass when the arm is fully retracted increasing by x, wherein x is the value in meters by which the arm extends. C can be defined by 2358.68 grams. As the arm is extended, the axis of rotation is in motion so theta, the angle in degrees between the vertical and the position of the arm changes linearly and as such, cannot be represented as a constant. However, since this angle is more difficult to derive, and since the angle between the position of the arm and the horizontal is already shown in the code for the controls operating the elbow, theta can simply be stated as 90 - theta_0, wherein theta_0 is the angle between the horizontal and the position of the arm. The torque due to gravity at the elbow can be represented as the function T = 2358.68 grams g(170.4 meters + x)sin(90 - theta_0) wherein theta_0 and x are parameters which can be taken from the articluation positions.

    Next Steps

    Being able to model torque as a function will allow us to understand how much torque is needed for the robot to stack a certain number of stones. By identifying the non-constant values of the torque function, we will be able to analyze what specific values produce the best robot performance, as well as whether that performance can be improved by lightening the load on the arm.

    Logarithmic Spiral Update

    Logarithmic Spiral Update By Ben

    Task: Update the Logarithmic Spiral

    As the design and build of the robot progresses, many components must be updated to be compatible with the current design. The logarithmic spiral, which was used to linearly decrease the load on the elbow with a bungee cord, is one of these. The article for the original design is numbered as the 45th post in the engineering section and is dated 15-11-2019. Prior to updating the design, the part would interfere with the drive shaft for the elbow. This typically wouldn't have been a concern, as it provided a safe way to limit the movement of the arm, yet we have determined that we need a greater range of motion. To do this, we simply cut a small half-circle out of the spiral. This was a relatively simple fix which would allow us to stack the blocks higher, scoring even more points.

    The next fix was the mechanism for attaching the bungee to the spiral. We plan to attach a bungee from both the front and back of the spiral to generate a greater rotational force. A design issue we encountered was running a bungee to the back of the spiral. There was no simple method for attaching and containing the bungee. To overcome this, we decided we would attach the bungee to a string from the back of the spiral. The final spiral design required two individual machined parts. Each part would have a chamfered edge, forming a channel when the two were put together, allowing the string to run within that channel. The two parts would be connected using three new holes to prevent the string from wedging itself between the two.

    The image below highlights the changes made to the original part. The chamfers along the edge were added along with three holes to connect two of the parts. The half-circle is also highlighted. These changes should enable us to assist the elbow in lifting the arm with greater efficiency than with the previous version of the spiral.

    Next Steps

    Our next steps are to machine the two parts and determine how much tension we need on the bungees to generate enough torque to assist the elbow.

    Modeling TomBot Articulations

    Modeling TomBot Articulations By Ben

    Task: Model TomBot's Articulations in Fusion360

    Modeling articulations is important for many reasons. The first of which is being able to effectively strategize. Having an idea of how the robot can move allows the team and drivers to understand the physical limitations of the components as well as enabling the drivers to determine how to control the robot most efficiently. Without such abilities, the drivers would only be able to visualize the robot's movements once it was constructed or a prototype was created. Drivers may also require new articulations which could be modeled and tested without having to program the movements.

    The second reason for creating robot articulations is to assist the coders. It is important for the code team to visualize articulations because it allows them to better choreograph the movements of specific articulations. Coding is hard enough as is, but having a reference is certainly helpful after coding something for hours and hours without an end in sight.

    To enable articulations on the model, joints were added in Fusion360 to allow motion. For our model, we added three rotating joints. One for the turntable, elbow, and gripper. The model also required 3 slide joints for each stage of the linear slide, all of which providing me with considerable trouble for something that supposedly just moves in a line. Fusion also allows us to set restraints to limit the motion of the joints in the model. This is useful because it allows us to animate the joints like how they would function in a real environment, along with making it dance until it apologizes for all the strife it has caused me throughout my lifetime.

    Next Steps

    The next steps for the robot model are to update the gripper to the most recent gripper. This gripper has already been modeled but needs to be added to the robot assembly. We would also like to begin modeling our second robot from scratch. Modeling the second robot is critical if we are to use the CNC to construct components for the new robot.

    Calculating Torque at the Turn-table

    Calculating Torque at the Turn-table By Bhanaviya

    Task: Analyze torque at the turn-table and how it affects our choice of motor sets

    We want to know if we are using the best possible motor set on our turntable. Since our turn-table is programmed to rotate at the fastest possible speed, we are not too concerned with a motor that turns faster but rather one that has a higher level of control and produces a higher output torque. A faster turret gives us less control when we are turning on the field and we want to reduce the time we spend trying to get the turntable in the right orientation. So, it's time to replace its motors. Currently we are using a Neverest orbital motor on the bevel gear on the turret which has a stall torque of 0.23Nm. With a torque this low, we are not utilizing the turret to its maximum capability. We want to replace this with a REV HD Hex Motor with a double planetary cartridge. REV offers a manual which allows the user to see the exact gear ratios and output torque produced by each combination of cartridges. Based on the cartridges we have right now, two 4.1 cartridges have the highest output torque as per the manual. But we don't want to replace our current motor just yet, until we calculate the exact amount of torque and analyze whether this is a good amount.

    The gears operating the turntable are an 8:1 pinion gear and a 2:1 bevel gear. Thus, their compounded gear ratio is 16:1. Using this, we can find the output torque produced by our current motor which can be found by finding the value of 16 * 0.23Nm * 3.7 which gives us an output torque of 33.6. Now, this value can be higher so if we switch out with the double staged 4.1 HD Hex Motor, we get a compounded gear ratio of around 13.1, according to the REV manual. The stall torque for these motors are 2.1Nm which is significantly higher than the amount produced by the orbital motor. Plugging both these values and the 16:1 gear ratio of the turntable gears, we can find that the output torque produced by the turntable REV planetary motors can be found using the equation 16 * 2.1Nm * 13.1, which equates to 440.16 Nm.

    Based on these calculations, we can find that the planetary motors produce a significantly higher amount of torque and will give our turntable much more control and precision when operated. This amount of torque may cause some concern on how much the slower the turntable will be; as such, we also calculated the linear speed of the turret. To do this, we have to find the rotations per minute (RPM) of each motor. The no load RPM for the 3.7 motor is 1780 RPM. By dividing this by its gear ratio, we can find the RPM which is 1780 RPM/3.7Nm which is equal to 481.08m/s. As for the REV motor with more torque, its no-load RPM is 6000 RPM and when divided by its gear ratio of 13.1, we get a linear speed of 458.02m/s.Although this is a lower linear speed, the difference is very little, showing that the new 13.1 motors will not reduce our speed by much but will have a much larger effect on the output torque of the turret, thus maximizing the turntable's efficiency.

    Next Steps

    Since we determined that our current turntable motor needed to be replaced, our next step was to make the physical switch on our bevel gear system on the turret. However, we are yet to test how much of an improvement the replacement will be so that will be our next goal. If we find that the motor set can be further replaced then we will use calculations similar to the ones in the article depending on whether we want to reduce or increase torque. Our next qualifier is this upcoming Saturday, so the new motors should improve our turntable control for the match-play portion.

    Dissecting the Turret

    Dissecting the Turret By Karina and Cooper

    Task: Figure out why the turntable isn't turning

    Just as Iron Reign was at the point of getting driver practice started and hunkering down to do autonomous, the turntable stopped working. The issue was that there was heavy skipping of teeth between the planetary gear and pinion gear which drove the turntable. Still, there was no obvious reason for why the gears had suddenly disengaged.

    To get to the root of this issue, we took to dissecting TomBot. We had to detach the metal frame which supported the turntable from the chassis just to get a better view of the problem area.

    Ultimately we chalked it up to the metal plates shifting on the polycarbonate circle of the turntable from all the movement. Our solution was to shift everything on the turntable over a small amount in the direction of the point along the planetary gear where the pinion gear engaged so that there would not longer be skipping. We got to work with but drivers and pliers to detach the turntable attachments from the turntable, and then the slip ring, and then the circular polycarbonate plate from the mass of motors, wiring, gears, linear slide, and the gripper that make up the arm. Once we had the circular polycarbonate plate isolated, we used a dremel with a drilling bit to widen the holes through which the bolts attached the entire arm system to the plate. We figured shifting out the turret may alleviate the issue.

    Next Steps

    We will have to find a more solid solution for this in the event that this becomes a recurring problem. I suspect that the underlying cause is that the materials that we used for either printed planetary gear or the polycarbonate plate upon which the whole arm rests could not handle the stress of the torque and speed of the turntable. Going forward we can conduct some material strength tests to determine if they can handle the stress, or if we should find a replacement. To be frank, even after dissecting Tombot, we were not certain about the cause behind the planetary gear disengagement.

    Snapdragon - The Beginning

    Snapdragon - The Beginning By Bhanaviya and Aaron

    Task: Begin our 10th gripper design

    As you could probably tell from our plethora of gripper articles, here at Iron Reign we have one too many grippers. And now its time for another one! We could do a whole post-mortem analysis on what went wrong about our build at our last qualifier, but for the most part, the design was consistent, with one underlying exception - our gripper. The finger gripper was a revolutionary piece of work, and has gone through a whopping 4 different iterations. But as all good things, its time must end. The issue was that the finger gripper lacked precision when it turned and was not quick enough in picking up blocks, requiring excessive control on the drivers' end to be able to focus on a stone and pick it up. In a speed-based challenge like this year's, this was not ideal, so it had to go.

    A slapband in action

    In it's place stands the Snapdragon, its quicker, more rugged replacement. The snapdragon functions as a passive gripper - at its core, it works as a slapband would. A slapband is, simply put, a wristband that wraps around one's wrist when slapped with enough force. Similarly, the snapdragon's closing action is an elastic-powered snapping action that is physically triggered when the gripper is lowered onto a stone. It's ability to grip is a direct result of the lower metal "flap" below the larger rectangular plate above. The effectiveness of this flap relies on the precise placement of rubber bands holding the flap to the plate above it. However this also means that the plates must be triggered in a very specific manner so that the gripper closes down at the right time.

    Next Steps

    The beauty of the snapdragon relies on its ability to be self-triggered. However, it would still need to be reset after "snapping". This would require use of a servo. The servo would need to be able to close down on the stone, but this also means that the movement of the gripper needs to be controlled such that it does not snap upon contact with any other surface. Trying to find a balance between this passive action and the servo's movement will be our primary task since the gripper isn't ready to be mounted yet.

    Engineering Notebook Binder CAD

    Engineering Notebook Binder CAD By Jose

    Task: CAD an engineering notebook binder that is to be custom made

    We want to utilize our new CNC as best as we possibly can. Since we plan to CNC the second version of our current robot TomBot for regionals, the only companion that could serve a CNC-ed robot is a CNC-ed engineering notebook! Plus an aluminum-plated journal would also help us emphasize the iron part of our name to the judges (hi there, if you're reading this!). The first step is to make a CAD file for this binder which is what we have shown above. The most custom part is the cover, it features our team logo, name, team number and even outline of our robot. As per GM1, we can have 2 engineering notebooks so we will make 2 custom notebooks, one that reads "Engineering Section" and another that reads "Team Section". We plan to use piano hinges to joint all the panels of the binder, use polycarbonate as pockets, and steal some binder rings from other binders to be used for these. The panels of the binder will be made of aluminum and the cover will be carved out using our CNC.

    Next Steps

    The outline of our robot, TomBot, may be changed in the future but other than that all we need is to CAM the binder CAD to be able to make it using our CNC. Once the journal is printed, all that's left to do is add the rings, panels, and pockets to the actual binder.

    Snapdragon - The Sequel

    Snapdragon - The Sequel By Bhanaviya and Aaron

    Task: Improve the precision of the Snapdragon.

    Last week, we prototyped a new gripper called the Snapdragon. Now it's time to give it more complexity. The Snapdragon is a passively-triggered gripper which closes down on a stone upon an impact-heavy contact with it. The main issue we're focused on solving is the impact which triggers the gripper - the gripper needs to be able to close only upon contact with the skystone and not with any other surface. To solve this problem, we added the servo horns, which make the snapdragon look like an actual dragon, for an increased comedic value. Before the servo horns, an abrupt stop by the metal plate of the gripper and the momentum of the "flap" below it were needed to grip a stone but this requires too precise placement of plates. With the addition of the servo horns, the servo horns physically trigger the drop so that the rubber bands holding the gripper in place can be tighter and have more grip.

    In addition to the servo horns, we will also be using a capstone dropper. The capstone dropper is mounted between the two servo horns, and has three small wired which will go through a hole at the base of the capstone. The dropper will be pre-loaded with the capstone and be released during the endgame. The capstone dropper has not yet been tested but we will get to that once we have controls to release the capstone.

    Next Steps

    We need to test the Snapdragon's new version extensively so that our drivers can get a feel for it. Next, since this is a passive gripper model, it would need more grip, so we also need to conduct materials testing on more materials to determine which material has the best grip and can be mounted on the gripper.

    Friction Coefficient and Energy

    Friction Coefficient and Energy By Trey

    Task: Calculate the friction coefficient of various off-the-shelf materials

    Before our last qualifier, we ran a couple material tests to find the friction coefficient of different materials. Now, since we've upgraded to a new gripper - the Snapdragon - a passive-intake gripper - we will need a newer material with much better grip than the ridged silicone oven-mitt we used for our previous 3-finger gripper. Since our new gripper works by slapping onto a block and clasping it, a better grip material will allow the skystones to latch more easily. As such, we ran a new series of materials tests to find a better material.

    The materials we are testing are a blue ice cube tray, a green oven mitt, a red oven mitt, a black shelving liner, a rubber cement pad, and a plate dipped in Plastidip. Three of these materials we have already tested before, which you can read about in Post 69 of our Engineering Section, but we will still conduct another test on them to keep our values in the new test consistent. The surface we are using is a 24in*24in wooden board. To conduct the tests we put a block on the selected material at the top of the board on its side and its bottom. Then we lifted the board while the block was placed in both positions and measured the height of the top of the board from the ground. We used the average of the heights in both positions to calculate the angle that the board was at using some simple trigonometry seen below. Then we used the friction coefficient equation which you can learn more about here in post 66 of our Engineering Section.

    Blue Silicone Ice Cube Tray

    When the wooden board was lifted, with this material keeping the block on it took 11.5 in until the block started to slide off. Using the equation: sin(θ)=O/H to calculate the angle at which the board was tilted which was 28.63°. Then, using the equation tan(θ)=friction coefficient, we found that the friction coefficient of the blue ice cube tray was 0.55.

    Green Silicone Oven Mitt

    We did the same thing that we did for the blue ice cube tray as we did for the green oven mitt. We lifted the board 12.75 in before the block slipped, which translates to a 32.09° angle, and a friction coefficient of 0.63. This is slightly better than the Blue ice cube tray but not the best by far.

    Red Silicone Oven Mitt

    We ran the same tests on the red oven mitt, the material we have on our robot now, and it was raised 12.5 in before the block started to slip which means that the angle was 31.39° and the friction coefficient was 0.61. This makes it an ok material just like the ice cube tray and the other oven mitt. If we were to use these materials, the grip of the robot would be fine; however, the testing of the materials is not about finding an acceptable material, it is about finding the best material.

    Black shelving liner

    This material was one of the best by far, with a height of 16.5in. The height translated into an angle of 46.43° and a friction coefficient of 0.96 which is a very high friction coefficient. This explains why this material is used on many robots like ours that want to effectively grab blocks. Another interesting note of this material was that unlike, every other material when this material surpassed its limit it didn’t slowly slide down, but it just fell all the way down the board all at once.

    Rubber cement pad

    The rubber cement pad was the most interesting and most effective material. It was made by freeze-drying some rubber cement in a mold. When it was dry it has the friction of a sticky hand. We lifted the board 18 in before the block slipped. That means that we had to lif the board at an angle of 48.59° which means that the friction coefficient was 1.13. The only downside to this material is that it has to be cleaned before match to get the best results out of it. Plastidip. This material was not very good. For one, It does not look very clean because of how clumpy it is. It also only had a height 12 in when the block started to slip, which means that the angle was 30° and the friction coefficient was 0.58.

    Next Steps:

    With these numbers in mind we are now able to decide which material we are going to use on the gripper which is going to be the rubber cement. We also know that for future seasons we can use both the shelf liner and the rubber cement to grab game elements. We are also going to continue to calculate the friction coefficient of different materials so that we can make sure that the Snapdragon gripper is the best it can be. This includes Geko Tape which we might use in the future.

    Final Weekend Before Regionals - Meeting Log

    Final Weekend Before Regionals - Meeting Log By Anisha, Cooper, Trey, Paul, Aaron, Bhanaviya, Karina, Justin, Shawn, Mahesh, Jose, and Ben

    Task: Use feedback from our presentation at DPRG and get ready for regionals

    A couple hours ago, we presented our robot at the Dallas Personal Robotics Group (DPRG), and we received insight on not only our robot, but also on our presentation, codebase, and our engineering journals. With this feedback in mind, and considering that we have a week before regionals, Iron Reign returned to the RoboDojo to do what we do best - panic, cram at the last minute, and repeat. (For reference, all our subteams will go into detail about their version of the scramble before regionals in separate posts. This is just a broader summary of our meeting).

    Today, the Code team mainly worked on improving driver controls, improving the implementation of a GRIP pipeline, and finalizing our autonomous path before regionals. Having just returned from presenting the works of our code-base at the DPRG presentation, the code team gained more insight on improving TomBot’s autonomous which will be their focus leading up to regionals.

    The Build team worked on Plasti Dipping the bottom of the foundation grabber for better grip when dragging the foundation. Plasti dip forms a layer of rubber on top of whatever’s being dipped in it and makes it stickier. Unfortunately later on, problems were discovered with the turntable. There had previously been cracks in the turntable from previous driving incidents but now they had gotten worse and were interfering with TomBot’s wheels. Because of a part of the turntable hanging off, the chain was being interfered with and stopping the robot. This was one of the most important tasks to do because obviously, without a functioning robot, there ain’t gonna be dubs at the competition.

    Before the problems with the turntable revealed themselves, our drivers got a decent amount of driver practice. They mainly focused on stacking as fast/efficient as possible. Towards the end of practice, they were also able to train new members of the team on driving. During practice, they also collaborated with the coders on improving the controls.

    The editorial team mainly focused on adding some finishing touches to the judging presentation after getting some great feedback from the Deloitte, and DPRG presentations (both of which have separate entries in our team section). They also worked on creating a research poster and a timeline of our notable events this past season to display at our pit during regionals.

    The design team mainly worked on improving the polycarb base of TomBot’s drive-train to CNC after regionals. To claify, our team is planning on creating a fully CNC-ed version of TomBot after regionals, regardless of whether we qualify to the next level of competition. As such, finalizing the CAD designs of each robot system will better prepare us to CAM these parts to create the next version of our robot. However, we currently plan to still replace the current polycarb base with the custom one since as mentioned earlier, our current base is not in the best shape. The design team also worked on creating a model of our pit design for regionals, which you can see down below. Having a well-organized pit benefits both us and any pit visitors, and regionals was no exception. Finally, they also worked on the CAM of the binder for both our Team and Engineering Sections, which will be custom-cut in aluminium using our CNC mill. For more information on the to-be CNC-ed binder, you can take a look at the “Engineering Notebook Binder CAD” post.

    Next Steps

    Although we had a significant amount of progress today, there's still plenty to do. Over the next weelk, our main goals will be finalizing our autonomous, getting our binder and new polycarb base manufactured, and ensuring that our journals and posters are ready to print for regionals.

    Designing a New Build Plate

    Designing a New Build Plate By Ben

    Task: Model and CNC a new build plate for TomBot

    The renowned architect Frank Lloyd Wright once said, “The longer I live, the more beautiful life becomes.” This, however, is not the case for our build plate. Throughout the course of the season the plate has seen extensive use and has endured much abuse, which can be seen in the large cracks forming on the plate. Although there are many temporary remedies, such as attaching plates to hold it together. These are not permanent solutions and not only appear bad, but can only temporarily reduce the problem, as more cracks will inevitably form.

    The first build plate was cut from Polycarb on a bandsaw from a pattern. This process resulted in many imperfections and uneven cutting, subtracting from the sleek circular design. This second time around we’re going to completely CNC the whole plate, including the wholes for bolts and wires. Using a CNC ensures a greater precision and guarantees a higher quality build plate.

    Cracks weren’t the only problems facing the first build plate. Drive testing revealed a major flaw with the design, the flaps that folded down from the plate were too short, causing the foundation to get stuck under the robot during matches. This is obviously undesirable as no one likes a robot who drags a giant plastic plate around the whole match. To fix this we just slightly extended those flaps on the model to extend past the height of the foundation. There was also another issue, the bolts that secured the omni-wheels to the build plate were difficult to access because they were to close to one of the Rev rails. To fix this we just slightly increased that distance but also had to ensure that there was enough length on the ends of the axle to comfortably secure the wheel mounts. Other, smaller, issues such as wiring holes were also solved by providing adequate space for wiring next to the expansion hub mount.

    Above you can see an image of the completed build plate. To ensure accuracy one side was developed them mirrored. This removes any variability within the model and creates a symmetric object. The screw holes were created by imposing the turret mounts and rev rails from the previous robot model onto the current one, providing an accurate placement for each hole.

    Next Steps:

    After completing the model, we will print the pattern on a large sheet of paper and verify the placement of all the components that are to be attached. If there are any inaccuracies they will be fixed. We then have to develop a CAM path for the CNC machine. Construction of the second robot will begin once the second plate is completed.

    Spicy Side Shields

    Spicy Side Shields By Jose

    Task: Design and CAD/CAM some spicy side shields

    In order to increase the spice factor for TomBot, we need to custom machine our own side plates out of aluminum using our CNC. The design is pretty simple, just a plate with our team number, but there are some other features such as the curved top. This keeps the side plates from being sharp and add some aesthetic to the design. Also, since the team number is to be put out of the aluminum, the circles inside the '8' need some strokes to keep them in place. To follow the font used these were at a set angle and thickness as seen above. The stroke for the '6' was also thickened to add some support as previous years' side shields have proven this stroke to be weak. Finally, there are holes on the top corners for the alliance markers. The idea for these is that a rectangle with both a blue circle and a red square is screwed to the top and is spun to show the color corresponding to the alliance we are in while the other color is hidden behind the side shield(of the spicy variety).

    Next Steps:

    With a CAM file of these (if not already obvious)spicy side shields already made we can immediately machine these on our CNC during our next meet as well as screw them onto TomBot. Since we have a circular chassis we will have to bend the aluminum, which shouldn't be too hard.

    Milling The Side Shields

    Milling The Side Shields By Jose, Justin, Trey, Paul, and Shawn

    Task: Mill the spicy side shields for the competition tomorrow

    In typical Iron Reign fashion we are making our side shields the night before regionals, as with many other things. The paper side plates look too jank on our robot that we are trying to make look professional, so we are going to use aluminum instead (a post covering the CAD and CAM of these can be found in a previous post). Since we are still fairly new to using our CNC it took us a while to get started, we broke 8 3mm mills before any major portion of the first side plate was done. After a few hours we were able to complete the milling of the numbers which we can use to label things like CartBot. To finish quickly as we were getting impatient, we used a 6mm flat mill to do the outside contour, some loose placement of the aluminum led to it drifting as this final stage occurred, but overall it finished quite well! After all these hours of suffering we still had to mill a second one this took a while, but not as long since we were used to the procedure.

    Next Steps:

    All that's left is to show off these aluminum side plates tomorrow at regionals!

    The Revenge of TomBot

    The Revenge of TomBot By Bhanaviya

    Introducing...The Revenge of TomBot!

    A long time ago in a galaxy far, far away there was a robot named TomBot. TomBot was a circle, a spinning circle with a turret and an arm that could extend to glory. Sadly, his reign was not destined for longevity - his cruel creators cut it short before he could enrich the FIRST world with his greatness. But TomBot remained scheming for many, many days, and in his wake followed... The Revenge of TomBot.

    That's right, we're building another robot! Even before our disasterous robot performance at the North Texas Regional Championship, we realized that our current robot, TomBot, lacked one defining one feature - class. Of course, only way to give a robot class is to bring a CNC Mill into the picture. The essential design of the robot will remain the same, but all parts, from the polycarb base to the the turntable mounts will be custom-cut and designed. Being able to custom mill our parts for every subsystem of the robot will also give us better control over the functionality of TomBot's design.

    Next Steps

    We will still be using TomBot in its original version for testing our code and drive practice and their corresponding blog posts. However, from this point onwards, every build post in our engineering section will refer specifically to our new robot - The Revenge of TomBot, coming to theatres near you.

    CNC a New Polycarb Robot Base

    CNC a New Polycarb Robot Base By Justin

    Task: CNC a new robot base

    We finished manufacturing our new base today, with very little difficulty, but a few flaws. The CAM was already designed so all we had to do was run the operations on the CNC. We drilled out the various sized holes, cut out the inner wheel slots and cable holes. Next was the groove along the edge to fold the side flaps along, which was a leap of faith because the orientation and position of polycarb on the CNC had shifted, which meant we didn't know exactly where we had it originally. We got it as close as we could remember and then ran the funky groove operation, which turned out to have pretty close to perfect alignment. Finally, we cut out the outline of the base, with flaps to fold down to increase the strength of the polycarb and to reduce flex. After looking at our finished project we noticed that the center slip ring hole was not cut. The hole is for general cable management and for the slip ring wires to reach the REV hub under the robot. We checked the CAM and found that it had been left out of the inner contours, so we made an operation for it, and cut it out separately. The build plate was finished on the CNC side of its production.

    Next we used attempted a new way to fold down the side flaps to make the structural ring of the base: some tasty oven baked aluminum. The plan was to heat the aluminum above the working temperature of polycarb, then place the edge of the hot aluminum in the groove and use the edge to make a straight 90 degree bend. We found that aluminum and polycarb just don't transfer heat very well, and ended up with a hot piece of aluminum and cold polycarb. Our less preferred alternative solution was the classic torch bend, which was prone to bubbling if rushed. We took our time and were very careful about how much heat we applied, so we only ended up with a few bubbles. Regardless, this was a major improvement over our previous build plate.

    Next Steps

    We are now ready to start mounting our subsystems onto the new base. We should first start with the drivetrain and the turntable. We also should document any errors we encounter with the new build plate, so we can fix them in CAM and make another more polished attempt. Our next CNC parts include boring out gears to fit on our big wheels, and cutting out more banana shaped mounts for the turntable.

    TomBot v2- Gripper Triggers

    TomBot v2- Gripper Triggers By Jose

    Task: CAD, 3D print and test new, better, and more aesthetically pleasing gripper triggers

    Since our gripper follows a design similar to a slap-band it needs a trigger to close it, for too long we have used a bent REV beam with screws on the end to hit the nubs of a stone. This proved to be very inconsistent as proven by driver practice before and at regionals since the screws were too small of a plane to hit the stone, forcing the driver to be precise to hit close the gripper. To help with this some better triggers were CADed by using the CAD of a stone as reference. since there is a servo on the top of the gripper the triggers have to work around that so a loft was made between the bottom circles and the attachment point on the gripper. Some filets were used to clean up some edges and this was sent to the 3D printer. At first the triggers were too short so they were extended by 2cm later on.

    Next Steps:

    With the print done we can test these triggers on the actual robots to test its viability on TomBot v2.

    Robot in 2 Days - But in CAD

    Robot in 2 Days - But in CAD By Jose

    Task: CAD a robot for the Ultimate Goal Challenge quickly in order to get ideas for a final robot design and prototypes

    A new season, a new design challenge, and more opportunities to compete. Last season we participated in the Robot in 3 Days Challenge where teams race to build a robot for the new season as quickly as possible in order to accelerate the brainstorming and prototyping phase of the season. Due to certain circumstances this couldn't happen this season but overcoming the situation the idea of transferring the challenge to CAD arose.

    Day 1

    The first step of course is to come up with a design for this robot. Many ideas came and went, many ideas were inspired by previous seasons' robots, but ultimately the main design was decided over a few hours and a basic CAD model was made. A time lapse of this can be seen here:

    Since I was really lazy today, I mean since coming up with the design of the robot took a while and I was very busy today not much could be done in the first day. I began working on the claw to grab the wobble goal and taking inspiration from the one used in the xRC Sim version of the game(the sim can be found here: https://xrcsimulator.org/downloads/) I decided on a simple arm mechanism with a hook. The hook is designed to be passive, it's wide enough to go around the pvc pipe of the wobble goal, but small enough such that the top of the wobble goal can't escape as easily. Since the wobble goal isn't as heavy the arm doesn't need such a high gear ratio, so I went for a 30:1 final gear ratio.

    Day 2

    Day 2! Time to do everything I was too lazy to do yesterday, I mean too busy to finish. The first step today was to check how much length I had left over for the ring intake, this turned out to be a little over an inch, not much, but enough. Since I am going for a conveyor design for this robot a base is needed below it to not only support the conveyor, but to also make sure the rings don't fall since they will be travelling below the conveyor in order to feed into the shooter. Some supports were added with REV extrusions, which made things start to come together.

    Up next was to actually have a way to power the wobble goal grabber. However, this was really simple as I just needed to add an ultraplanetary motor and a belt.

    Next on the list for today was to actually make the conveyor belt, this will have "spikes" in order to grab the rings. The conveyor is about 6 inches long to allow for some extra room when intaking. Spikes are in pairs and spaced about 3 inches apart. This was a simple assembly and I was able to move on to adding the pulleys and bearing shortly after. As far as a gear ratio goes, a direct drive 19.2:1 should do.

    It's the final countdown..[plays the final countdown music], time for the final sub-assembly, the shooter. This was very simple to make. Holes in the polycarbonate base were made to allow for the shooter wheels(I used the new goBilda Gecko Wheel) and these were also direct driven with a 5.2:1 goBilda motor. This may be too slow but since this is CAD, it isn't very easy to test this. The process of getting renders of this robot proved to be resource demanding but it got done and here is the final product: