Robot in two days (Ri2D) is an ideation process Iron Reign goes through to explore the new seasons and brainstorm designs and ideas for the game. One key aspect of this year's robot in two days was the chassis. A part of the chassis included was the system too ascent onto the first level, so we repurposed the Skyhooks from last year's Center Stage season to do so. The skyhooks rely on a custom ratchet latch to hook onto the rung and lift the robot up. They are tensioned by a bungee and their height is adjusted by a spooled string. Thinking about the high ascent, since the rules only prevent touching the high rung while touching the ground, theoretically the robot can jump off the ground for a brief moment and then grab the high rung which would allow the robot to score all 30 points. Unfortunately, we were only able to accomplish the first ascent instead of the jumping robot, but the ideas we did in Ri2D will help us as we progress through the season.

Since we chose to build on the swerve platform that we developed over the summer, we needed to make some additions to the code for the swerve platform. The swerve module is built up of two separate rotating parts, a platform, or as we like to call it, a frame, and we have the swerve module itself. While coding the swerve module in the summer, we decided to ignore the rotation of the frame and just focus on translation in the direction that we wanted for simplicity’s sake. We could accomplish this with just one encoder; however, in order for Swerve to be competition ready we need to be able to control the rotation of the platform too. To accomplish controlling the rotation, we decided to drive one of the Omni wheels that were there previously to balance the mono swerve platform. We accounted for this by implementing an unwrapping function based on input from the IMMU in the control hub that helped maintain global bearing despite platform rotations due to the driven Omni wheel. This gave us the ability to decouple the direction of the swerve module and the platform and naturally created a field-oriented driving system.

One major component of the intake system we designed during robot in two days was a pincer gripper claw. Attached to a linear slide outtake, there is a claw with two separate 3-d printed parts that pinches the specimen. This design worked fairly well and it effectively secures the samples. The second part to the intake system was a beater-bar to intake the samples from the field. The beater bar we built used rotating tubes to intake samples onto a platform. This was a simple design, but we are planning to add a color sensor and diverter to only keep the samples of the color we want to make the beater bar system more efficient.

Task: Experiment with Claw Designs

Today we built a proof of concept for a roller claw concept that we came up with. This claw took inspiration from a passive rubber band pincer gripper designed by a team on the unofficial FTC Discord server. It also took inspiration from a previous roller/beater intake designed by Iron Reign for the Relic Recovery season (see below).

To create this claw, we used surgical tubing as our elastic/tensioner and custom NinjaFlex TPU rollers. After testing, we noticed that the surgical tubing did not provide enough tension to properly grip samples or specimens. Additionally, we acknowledged that while all elastics will start to loosen, the surgical tubing would undergo this process at a quicker rate than other options. On a more positive note, while the custom rollers did unfortunately come out bad due to using wet filament, both the material and roller profile seem promising for their intended purpose. It did need a slight increase in stiffness, so we plan to increase either the wall thickness or the sparse infill percentage.

In the future, we hope to test extension springs as our elastic instead of surgical tubing. We believe this will be more durable in the long run and will provide enough tension in order to grip the specimens and samples. We also want to increase the structural stability due to this proof of concept being a very quick and janky design/prototype. An example of this issue is the claw halves not having any physical limits therefore making the whole assembly too wobbly. With future improvements, we are hopeful that this claw has potential to be an excellent and versatile intake option for the season.

Task: Improve our Roller Claw Concept

We’ve made progress on the 2nd version (V2) of the roller claw that is more structurally sound and has an improved intake. To improve the structural stability we added a second standoff between the plates of the claw halves to stop them from twisting while intaking. Additionally, we added a large pyramidal structure in the center of the claw in order to help align samples during intake. This structure also doubles as a physical stop for the claw halves so they can’t move past their intended minimum limits, an issue we observed during testing of the prototype.

We decided to test a variety of springs, moving away from surgical tubing, and ultimately landed on a 1.1cm x 3.8cm x 1.2cm extension spring. This spring produces enough tension to properly clasp onto samples and specimens alike even when encountering “turbulence”. Despite it still losing tension overtime, like surgical tubing, it cannot untie itself and will take a longer time to lose enough tension for the impacts to be noticeable. A con of having this increased tension is that the claw does require more precision during intake and more force than the previous version due to the spring’s higher tension, something that is an unnecessary burden. While we are confident this will be our final form of tension, we may test out different spring strengths or other forms of tension. Another change we made was to increase the number of rollers, from 2 to four. While some of the rollers were iffy, the increased number of them made intake more efficient. After further testing, we came to the realization that the stiffness, material, and current roller profile worked well for what we wanted. We also decided that stiffer rollers are not needed; however, testing rollers with more walls and/or higher infill percentage is not out of the question as it could produce improved results.

For the next version we will focus heavily on the coding aspect. We plan on adding a color sensor to locate preferred color samples. Additionally, we want to embed a color sensor into the tip of the aligner to detect whether we have collected the preferred sample or not. We will also finalize the servo mounting system to start powering the rollers. Despite this version requiring more precision due to the spring, by adding rotational movement to the rollers the intake will require less precision. We also want to begin printing parts out of nylon to test durability and tolerances. We believe this change in material will cause some revision on the design due to the difference between nylon and PLA.

Task: Analyze our League Meet 1 Performance

After every competition, the team sits down and runs a SWOT(Strengths, Weaknesses, Opportunities, Threats) analysis on the robot and its performance. Here is a breakdown of everything we learned using the SWOT technique after League Meet 1.

Strengths:

One of the biggest strengths that our robot has was auton reliability. In every single match we played, the auton always worked. Having this reliability allowed us to have a strong foundation and build off of this base auton in a more efficient manner. Another strength we possessed was good time management. The team was not late to complete any of the inspections, and we were always on the queueing table on time. The team was organized allowing us to run smoothly.

Weaknesses:

There was a missed opportunity on the code part since we were never scoring in the high basket in TeleOp or auton. If the build team had finished a little bit earlier, the code team would have been able to code the robot to score samples in the high basket. Scoring in the low baskets made auton almost pointless even if it was reliable. Specifically in the beater bar, the window for the color sensor was not optimal. This made tuning inconsistent, and the problem was very obvious when it came to yellow samples since the belt stopped much later than it would have for red or blue samples. Overall, the belt of the beater bar was also much slower than we wanted since the belt was small.

Opportunities:

We want to better segment the time before competitions to make sure the build, code, and drive team all receive almost the same amount of time with the robot. Allocating time in this manner will allow the drive and code team to have an adequate amount of time to make sure other things are not lacking such as fine tuning in the code or not enough practice time driving. We want to practice driving under competition conditions to gain the most accurate data. We want to increase the speed of the belt and try to hang on the low bar with a new arm.

Threats:

The biggest threat to the team was a lack of coding time. If the code team received more time we could have scored the high basket. Scoring on the high basket would have let us receive almost double the points than we were actually scoring. Another major threat was not giving the drive team enough time with the robot. We would have won our last match if we gave the drive team more time since they would be able to figure out how to touch the low bar during endgame.

For the second meet, we want to make the following changes: We want to have two separate linear slides, a worm gear shoulder, be able to achieve 2nd level ascension, getting rid of the bridge, and continue to plan a new swerve chassis.

The SWOT analysis gave the team insight on what went well and what needed improvement. This feedback will allow us to have a base plan to follow for meet two. Ultimately, performing a SWOT analysis gives us very valuable and important information to help us develop the robot and the team.

Task: Create a reliable intake system for the Submersible

We developed an intake system using a 3D printed beater bar out of ninjaflex. The beater bar is used to pull the sample onto the platform. We used clear 1 mm polycarb to form the walls of intake. The walls curve slightly allowing samples faced in many angles to correctly position itself to enter the intake via the beater bars. The beater bars move via an axel connected to a servo. We also connected a color sensor to be able to detect the color of the sample. This will ensure we have either a team sample or neutral sample. If we collect something else, we are able to easily eject it. Due to the light from the sensor, the driver is able to view the color of the sample through the polycarb during tele-op.

Some changes we had to make were the beater bar and the walls of the intake system. We experimented with different sized beater bars and the amount of them. We finally decided to go with thin beater bars that are 15mm and 10mm and use 1 beater bar belt to continue the intake process, while 2 beater bars are on the first axel. This setup allows the samples to be taken in by a multitude of angles, yet continue through the intake until it needs to be ejected. The build of the intake was changed from a rectangle, to having a triangle-like entrance. This change allowed the edges of the samples to get caught and slowly turn the sample to the correct position, creating more intake positions of the sample.

So far this intake system works well. It can intake samples in almost every position, except completely horizontal. This can be fixed by slightly hitting a sample to turn it in-game. It does however allow some samples to eject unknowingly. Another issue we have found is it intakes slowly, causing cycle time to be relatively slow compared to other teams. Overall these are minor issues, and it is an effective intake that we will continue to develop.

Task: Analyze our League Meet 2 Performance

After every competition, the team sits down and runs a SWOT(Strengths, Weaknesses, Opportunities, Threats) analysis on the robot and its performance. Here is a breakdown of everything we learned using the SWOT technique after League Meet 2.

Strengths:

In our conversation, everyone could agree our key strength was the structure of our linear slide. Earlier on we decided to change our linear slides from string to belts. This change so far has proven our slide to be sturdy and effective. It had little to no shake when lifting, which was a key issue in earlier versions. It also extended easily using belts. We are confident in this subsystem's ability to function.

Weaknesses:

One of the main reasons we were not able to properly function our linear slide or beater bar was a weakness that we have had time and time again: Wiring. Even at the last meet and scrimmage, we spent a lot of our practice time rewiring the robot. At this meet the wiring was not properly done which meant our robot could not retrieve samples or properly use the linear slide. Another reason why the arm did not work was because the build was only 90% there. The arm was very wobbly at the point where it was connected to the beater bar every time we tested it. Finally, code only got a few uninterrupted time with the robot to perfect the code for the new version of the beater bar and the new linear slide. Overall, we can fix our weaknesses if we can create a better coordination system and focus ourselves on hard deadlines.

Opportunities:

After our discussion, we talked about the opportunities necessary to take, so we can effectively better our robot. An issue many people noticed was the bearing on the slide motor. These bearings are necessary to hold the belt and insure it does not slip. The current bearings are too small and do not effectively do this job. We believe these bearings need to be thicker or squeezed closer together. Another opportunity we discussed was our next goals for winter break and for League Meet 3. We hope to finish the quick issues this week, to give our coders time to code leading into winter break. We also have dedicated a few members to work on our new chassis and robot design while further improving this one. We hope to implement our swerve summer project into our new robot and have 2 arms by League Meet 3.

Threats:

During our discussion, we talked about how sometimes the team lacks a sense of urgency and how we get sidetracked easily. We reflected upon this threat and tried to figure out ways to fix this problem. We knew that socializing time was important because it helped creative juices to flow, but at the same time it is necessary to focus and make sure stuff gets done. To combat this, we created a specific calendar for specific goals. This will allow us to see exactly what needs to be done and hopefully allow us to have a better sense of urgency.

On December 20th, Iron Reign began cutting carbon fiber to assemble our redesigned Arm and Shoulder for V3 of our Into the Deep robot.