UIUC Ri3D 2020

Robot reveal!

A more in-depth technical reveal:

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A bit late, but here is the github link to our code base: https://github.com/wdoherty/IllinoisRi3D_2020

Feel free to ask us any questions!

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Will you be sharing a robot CAD?

Yep! We did everything off of a crude 2D sketch, so we need to convert that to a 3D model. I plan on getting it done tomorrow, had to catch up on some sleep and real life stuff today.

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How well does the robot handle moving two balls at once, when they’re rubbing against each other? We haven’t been able to test it because we haven’t gotten more game pieces yet. From what I’ve heard from other Ri3D teams though, one-sided conveyors that rely on the balls rolling don’t work well when the balls contact each other.

Well done team UIUC! Ri3D is not an easy thing to do.

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We heard about that issue the beginning of day 2, and didn’t have time to modify our design. We also only had one game piece, but when we get more we will update everyone here on how this particular mechanism behaves.

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Sorry for the delay, I’ve finished the rough CAD of our Ri3D robot, which can be accessed at our GrabCAD. I forwent any rivet holes because I only had about 4 hours to work on this.

Let me know if you have any specific technical questions, I’ll try my best to answer them. Also, we should be able to update everyone on the fidelity of the ramp mechanism with more balls this weekend or on Monday. Thanks!

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How much spacing did you do between the belts and plywood base? Have you been able to test with multiple balls? If so, any issues?

We initially had a compression of 1", so 6" between belts and the ramp surface. We have changed it to .625" compression and we are getting better results. Testing with multiple balls, we haven’t seen any issue feeding or storing balls. Sorry for the delays, we hope to have at least a more detailed technical update tonight or tomorrow, maybe a short video as well.

where did you get that blue cable for the climb and how did you attach it to your winch gearbox?

We bought a 1" wide ratchet strap (2-pack) from Walmart for about $5. We then cut them to length, and made two holes with a heated-up 3/16" rivet. We used a small butane torch to head the rivet, the nylon melts away and the hot rivet prevents fringing around the hole (DO NOT DRILL HOLES). We attached the strap with 2x 3/16" rivets into a thunderhex shaft, see image below.

We are ordering some PTFE film to hopefully solve a critical issue with the ramp design, will update when we get the film in shop. Thanks!

Will you be releasing a BOM for this? Thanks!

We weren’t planning on it but we can maybe throw something together when we get the chance.

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We were inspired by your build! Is it possible to have you email me a list of parts to help us get started? We are a rookie team with no prior experience.

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You should also check out:


It’s highly documented and designed with rookie/lower resource teams in mind

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We’re glad you have some inspiration! As suggested, I would look at the Everybot for more guidance and ideas for a rookie/lower resource team. Although we designed our bot as a MCC, there are several things that are done better on other bots. We may make a detailed BOM in the coming days, but most members are either out of town or have started school and are busy. If you are still interested in a similar design, you can check our CAD, linked in an above post.

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Sorry for the bump, but I was contacted and told the native SolidWorks model wasn’t loading because the GrabCAD partner space was broken. I made a pack 'n go of the assembly, so all toolbox components should be in the partner space’s zip folder now. I also added the 2D profile sketch we used, someone was asking how we figured-out geometry. Thanks.

What gear ratio did you use on the versa planetary gearbox?

I couldn’t tell you the exact ratio off the top of my head, we mainly just used whatever we could find. I can take a look tomorrow, but my best guess is we found a ratio ~20:1, which would give us ~8 surface feet per second on a 775Pro, we ran our conveyor at ~60% IIRC to get around 6 surface fps.