Drivetrain jerk

Our 6m 257 rpm drive keeps jerking after deceleration and that screws up all the disks and also messes up our intake. We are using stopping to brake; any suggestions?

Are you able to post a video of what is happening to clarify? Are you suspecting it to be a mechanical or coding problem? If you suspect it could be code, could you post your drivetrain code?


I would recommend setting your motor to coast when stopping


My first suggestion would be to check if there is any friction, I will tell you better how to do that and other suggestions, but I am in history right now.

There might be a part on the bottom of the robot which digs into the tiles when the robot pitches forward as it stops. The part is likely not touching the ground most of the time and only does so when the robot stop.

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I second this.


Two questions. Would you like the robot to stop immediately, or is it allowed to coast according to momentum? Also, what’s your brake set to?

I third this.

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Consider this suggestion drawn and quartered.

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I had a team using VEXcode V5 (Blocks and Text) and the intake would stutter. It looked like the motor was receiving start / stop commands but it was a very simple program using velocity. The resolution was to create a new (cut / paste) program and the issue went away.

I am just noting this in case other teams experience this behavior, Vex may want to look into their latest update.

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I fourth this because coasting also helps not overheat the motors.

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Drive the motor with volts, not with RPM. It is trying to rapidly change the rpms of the motor and there are issues.

My team had the same problem, all you need to do is add weight on your robot and it should be good.

Adding weight should almost never be the solution to your problems, I would highly recommend switching your drive motors to the “coast” break mode and reducing weight.
When you add weight especially in relation to your drive base you are just making the motors work harder than they have to, which can cause them to overheat faster and is overall less efficient


If I had a dollar for every time a cut/paste or redo fixed broken code…

The OP did mention a 6m drive… perhaps it’s braking too well. Maybe change some of the motors to coast and leave a couple set to brake.

I agree with this, the only situation where weight should be added is what we had happen this season. Our front left mecanum wheel was slightly smaller than the rest for some reason, so it needed to be weighed down to touch.

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Uhhh, you should look into that. Probably your chassis bending/flexing.

We did, the wheels rollers are kinda weird. It is ok, we fixed it

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