2910 CAD Release 2019

Team 2910 Jack in the Bot is excited to release the CAD for our 2019 robot, Jordan!

Parasolid (recommended for Solidworks):
FRC 2910, 2019 Robot Assembly.x_t

STEP:
FRC 2910, 2019 Robot Assembly.STEP

Our code release will be coming soon as well.

Please feel free to ask any questions

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Where the 2x1 L’s around the NEO’s on the swerve to protect the motors from getting clipped in the bumper cut outs?

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Why the one singular flex wheel on your bottom roller? I think I asked this at a competition but it still annoys my sense of uniformity.

Also, how impactful was the constant current running through your top roller?

Yes, we broke a total of I think 7 Neos at our first competition, but we have broken none due to clipping since.

This is because the pulley driving the bottom roller stops us from putting on another stealth wheel. Since compliants are half the size (and easily purchased), we used one of those. The other option is cutting a stealth wheel in half and putting it on, but that’s a little janky.

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Thank you for sharing!

What do the three cylinders underneath the PDP do?

Those are our “kickstand” pneumatics, which allow us to take up less of the lvl 3 hab. The one farther back simply gives us a place to rest on so our bumpers are above lvl 3, while still being far back enough that we don’t tip back when we have our wheels off the hab. The two closer to the front allow another bot to rest on the front of our bumpers so we can have a lot more of the bot hanging off.

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This is probably a bit of a weird question but recently I learned some people cad bumpers incorrectly. Do you guys cad your bumpers as a block and add fillets or use a sweep?

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The top roller was not running all the time. It would run when the operator held down the intake button, when the driver held down the release button, as well as when one or both of the beam break sensors was triggered meaning there was a cargo it should hold onto. We were driving it with a very low power when stalled and holding onto a ball such that the current draw was not excessive.

I’ve been waiting for this since the reveal video!! So excited!!!

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We use a sweep

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The main reason they are needed is because our robot only has 4 wheels. With the rear 2 wheels off the hab we needed something to hold up the robot so the bumpers are above the surface of L3 so the climb would count.

We added this to double climb with 1323. We got it dialed in when we got to champs. The double climb can be seen at the end of this practice match. https://youtu.be/poGTvTQrDug?t=134

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Ah ok, I meant while you were holding a ball. That makes sense though, thanks.

I haven’t looked at the CAD yet, but how did you eliminate backlash in your cargo mechanism?

Congrats on the great season. Beautiful design, thanks for posting the CAD!

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My favorite robot of the year, hands down. The attention to detail on this thing is stunning. Some of the parts you guys CNC’d are works of are all on their own.

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I feel like I became a better designer just looking at this model. Hats off for a fantastic season from you guys, and I seriously can’t wait to dig into this model more. So cool!

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There were a couple things we did to help reduce backlash in our cargo arm.

Tensioning chain properly is important for reducing backlash. We used AndyMark’s inline tensioner (am-3914_35) to tension the chain. The arm gearbox was designed such that the chain run would be long enough to use an inline tensioner.

The smaller sprocket is connected to the adjacent gear with a versahub sprocket mount (217-3234) and bolts. This is still a pretty high torque part of the gear train so we would prefer to transfer the torque through the versahub key and bolted connection vs hex shaft.

For a gearbox that is a reduction, reducing the backlash on the output stages of the gearbox will have a larger effect on the overall backlash of the system when compared to reducing backlash on the input stages. There is still backlash in the arm caused by the gear teeth and gear bore to shaft clearance, but it is pretty minimal.

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I’ve uploaded this model to Onshape to make it a little more accessible for those that just want to poke around. Document title is " FRC 2910 - 2019 CAD Release" if you’re searching.

https://cad.onshape.com/documents/a2e1226ac2266fdb4b6cec4b/w/35352e5d7870e5c3627edee8/e/5f60dee40e0cbe32a4df4500

Enjoy!

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At what angle can you guys intake a hatch

I dont know if i’m missing something but can someone explain how they power their climber