My VRC team has a competition this weekend and one side of their drive train isn’t moving properly. At one point, both sides of their drive train wasn’t moving like it should. This happens after they’ve driving it during a practice run. After they let it rest for a few minutes, it starts working again.
They’ve replaced both motors, reprogrammed, and added two more motors so that there are now four motors to the drive train.
I can’t think of what else might be the cause of this issue.
It sound like their drivetrain is overheating. You can check if motors are overheating by going to the “devices” menu on the brain screen, then selecting the brain icon near the top, then selecting “view logs”.
Adding 2 more motors should definitely help make it overheat less, most vrc teams have at least a 4 motor drive, and some go up to a 6 or even 8 motor drive for extra pushing power and to prevent it from overheating. They can also try to reduce friction in the drivetrain, have them check for any axles not being aligned or bent pieces of metal which could be increasing friction, and make sure that the chain isn’t too tight.
Also, keep in mind that the drivetrain only needs to last for 2-3 minutes of match driving without overheating, as at competitions there will always be breaks to let motors cool down between matches.
Thank you so much for your reply! I saw something on the forum about overheating and using more motors. I suggested that, they tried it, but were still having some issues with it.
It was only a two motor drive train, so I’m sure that has to be the reason.
On back to back matches there’s not always time to cool down. And I get your point, but if you’re heating up motors that much… sounds like it’s time for a redesign. Just a matter of time till you are at a venue where it’s warm and you’ve got real problems then.
OP needs to monitor motor watts via the brain’s screen. Unloaded should be <.5 watts per motor. “Normal” driving is <2 watts/motor.
Yeah, I should have made it more clear that the 2-3 minutes number was the minimum to last a comp, a high-level drivetrain should be able to last 10+ minutes of intensive driving.
Also I thought I’d link this post by Xenon27 on building a drivetrain, it is a very good resource on general build technique to make a more robust and lower-friction drivetrain:
This is probably because of one of the three reasons below
One side of your drive train has more friction, so you have to figure out why that is the case. A sign of this could be that your motors are overheating too fast
Not all the shafts are in the cartridge, causing that one side to move a little bit more slower
A port on one side of your drive train keeps on disconnecting, causing the motor to just slow down the drive train instead of making it go any faster