Gripper Iterations Summary

Tags: think, innovate, and design
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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.

Date | November 9, 2019