4926 Offseason Swerve Drive

Peter, I don’t know yet. We may build this single module as a control test bed and if there is success and continued interest maybe! We’ll see. Thanks for commenting!

The first stage belt reduction is 12:30 and the second stage gear reduction inside the module is 28:66. The azimuth gears are 1:1 since that keeps the vex integrated encoder 1:1 as well which I have heard is very useful. All the reduction for the azimuth motor will be in the versaplanatery stages before the encoder.

Team 4926 has a Onyx One so we are pretty set there. We agree with @Gdeaver that the design experience and transition through to “making it work” is invaluable. If we were committed to using it for a competition season maybe we would go COTS, but since we are not, we are exploring this route.

Thank you for your comments to our student designer on this!

I think I misunderstood you when you asked why I used belts for the azimuth stage. I thought u meant the drive but I looked up what azimuth meant and realized you meant the turning of the module. My bad!

The main reason for gears was just that it was easy to find one (I guess that’s not a good reason). I need whatever I use to transmit power to have a large surface area so side loads on the swivel pod won’t bend the coaxial shaft. The larger surface area in contact with the mounting plates helps keep that from happening. That’s also why I have the large thrust bearing. However, I’ll look into how I can integrate belts into that stage instead. I have also heard belts have less backlash which is important in swerve.

I’ll look into those bearings as well. Thanks!

Excited to see you guys with are going for a swerve, can’t wait to see it.

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Wonderful Design, I love how simple it is. One question I have is, I don’t see an absolute encoder anywhere, would your plan be to just zero the modules every match? If so, I highly recommend using the absolute encoders, that way it takes away from forgetting about zeroing them every match.

Thanks! The vex integrated encoder is attached to the versaplanatery gearbox’s final output. It has both absolute and relative encoder settings and it is geared 1:1 with the module.

Also, to be clear, I was not asking why you were designing your own to discourage you. Designing a swerve is an excellent design challenge, and one I went through as a student not long ago. Keep working at it. I do encourage you to use the Onyx One more. It’s powerful.

Could you post a sectional analysis view of the drive shaft/what is supporting it? I’m concerned that the drive shaft could bend if the module hits something.

The drive shaft is just 1/2 inch thunder hex but there is a very large thrust bearing in contact with the mounting plate. The idea is that a side load on the module won’t bend the shaft because the thrust bearing can’t go through the mounting plate.

Here’s a little diagram in case my explanation didn’t make sense. I plan on making a career out of my graphic design skills :laughing:

I’m looking into using belts to control the module’s azimuth and my main question is: Would this kind of application of belts require a tensioning system? Normally in WCDs, belt tensioning is important but I am not sure if this would be necessary for rotating a module.

If you get the center to center distance correct it should not need a tensioning system. Our MK1 and MK2 modules do not have tensioners on the steering belt.

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Yeah it’s your call really based on how good you see your tolerances can be. We have slots in our drive rails so we can adjust tension as needed.

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Does your slotting system work well? I am already planning on doing that with the drive belts and might do it with this turning belt as well since I doubt our tolerances are as good as 2910’s.

Works fine.

I can confirm this as well. Some good ole nylocks is what we use. To get some added hold, we also place a small slice of coarse grit sand paper under our brackets with wedge washers. Swerve stayed tight through all 80 or so matches we ran this year.

I might copy that setup as well. I had never heard of a wedge washer before but after a quick Google search, I think they could be useful in a lot of other situations in FRC!

They’re very useful for application areas like this.
Our latest swerve was posted with CAD for reference. At 4.2 lbs, great control, and great performance specs, its worth a look if you plan to proceed forward.

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Wow that is a very clean design! Your grab cad description says it runs at 15 fps. How has that gearing worked for you guys? I can configure my design for 12 fps, 14 fps or 17 fps and I’m still trying to decide which one to use. I’m going for a zippy, quick drive kind of like 2910.

Our speed has been great. While we never have driven at max speed, we have amazing control on the field. Not to mention we have the perfect balance of speed and torque imo. We’ve burnt out defending bots cim motors in pushing matches, and also held a bot who burnt holes in the carpet trying to push us. Check some of our match videos. I’d suggest FiM DTE Finals 1. Or just watch out season recap.