Drive Stalling - Please Help

We are running our bot on four high speed motors geared 1:1 to 4" omnis. No encoders and the two sides are chained together. There doesn’t seem to be too much friction on it. Just recently, our drive started stalling. Before, everything was fine. After about a minute, one side will stall followed by the other soon after. After a few seconds it will start back up then stall again even sooner until I just have to give it a rest for a while. Why could this be happening?

My first guess would be to check the axles. They might have become bent over time and even a slightly bent axle is enough to cause major problems. Secondly, check the bearing blocks to make sure they are all intact and tight (once one of our bearings snapped in half). Make sure that none of the metal has become bent because that can cause lots of friction. Hopefully these will solve your problem. Oh yeah, also of course check that all the motors are working stuff, but I assumed that you have already done that.

With that said, I’m starting to think that there is something more universal causing these issues because the same thing happened to us around February. Thursday night before states, it was working like a beauty and then Friday morning the drive base doesn’t work for more than 30-45 seconds. I also have heard several other teams complain about this, on the forum and face to face at regional competitions. I’m not sure how practical this is, but maybe it is because of some firmware thing of RobotC or the cortex. My team was never able to figure out the problem despite replacing motors and doing everything I suggested at the top of the post. If any of you moderators are reading this, if you know anything, please post. Maybe make a new thread or something and tell us what you know. Anyhow, good luck and hope your issue is quickly solved.

My guess is that you’ve added more mass to the robot. Although you don’t have a high gear ratio, running high speed motors on lots of weight can cause them to Burn out, try slew rate

This has been happening to our robot too. After driving for 1:00 - 1:20, the right side of our chassis stalls, but the other side seems to work just fine. We have a brand new cortex and relatively new motors. Our robot’s motors are split over the cortex’s ports evenly and the front wheels are on the power expander. Our robot is not very heavy at all (mostly aluminum). Everything is up to date and works just fine until a minute or so into the match when the right motors fail. We have been working on changing our driving habits so that we are not working the robot so hard, but the problem persists.

Our wheels are geared for high speed and they are direct drive. They also have IMEs connected.

Is it possible that somehow the IME’s are causing the issue? I have noticed that lots of people that have this issue also have IMEs. We have them too. @JamesD22000 do u have IME’s?

We will remove them and see if that fixes it. Thanks.

Ok Good Luck!

Thank you for your reply. We do not have IME’s. I will likely replace the motors, add a slew rate, and cut power slightly.

Ok good luck. If I think of anything, I’ll be sure to post it.

how tight is your chain. Super tight chain can easily stress out your motors

It’s also possible that one of your motors shorted.