Swerve module randomly locking up

Hello again FIRST community!

I have a question about some strange behavior we’ve been seeing in our robot. The robot has swerve drive with MK3 modules, and occasionally, and seemingly without cause, one module will randomly lock up. The weird part is that it is sporadic. When the module locks, we can redeploy the code (with no code changes) and everything works fine again on the next run. That implies that it’s a software problem since if it was a hardware issue it would still be locked up until we made changes to the hardware. We even saw it happen to different modules at competition, so it wasn’t always the same one. Has anyone else seen behavior like this? Our robot drives well normally, but I’m very confused about this intermittent issue.

Here is our codebase for reference: https://github.com/5804/rapidReact2022Alpha .

Thanks for any info you can provide!

In saying

do you mean; the steering, the wheel rotation, or both?
What kind of motors are you using?
Have you tried power cycling to see if you get the same result as redeploying code?
Are you able to move the module by hand after powering off when this issue occurs?

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I believe both. The driver reported that when he tried to go straight, it would spin around the locked module. We are using Falcon500 motors. I have not tried power cycling and I will try that next time we see the behavior. I didn’t test if we could move the module by hand after the issue occurs since the redeploy usually fixed the problem. I can try that next time we see the behavior before we power cycle.

Definitely check if youre able to spin the wheel by hand as if the issue is a hardware one thats likely where it would be from the problem u described.
Also check the orientation of the wheels next time you have this issue, many teams (including my own) have been having a problem all season long where one wheel will decide it wants to be at a different angle than the rest for no reason. its annoying but usually goes away with a power cycle

Yes, this issue has been plaguing us. Our front left wheel is temperamental and will randomly just decide to go 90 degrees and stay like that. If you let the robot sit while enabled it will eventually go back. No clue what the cause is.


Do your Driver Station Logs report any brownouts? It’s possible that your controllers are losing settings when they lose power momentarily. Can you post logs from a session when this happened?

Its completely unrelated to brownouts or controllers at least for my team as we’ve had it happen with no controllers plugged in and brand new fresh batteries with no brownout warnings. We’ve noticed the same thing as CoolBudy1

It’s very perplexing and has never negatively impacted us in any matches it’s just random issues while trying to test in our practice space.
It’s almost always 1 wheel sometimes 45° off sometimes 90°

When we have issues with our swerve modules, best thing to do is put the robot on it’s side do u can see the wheels of the ground and then mine then in all directions so u can watch and see what the wheels do. That’s usually the easiest way to identify when something is off.

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