[apalrd]

We have a routine for auton where we run a PI velocity controller to 0 speed. It essentially rapidly ramps up a negative voltage command, then stabilizes around speed 0 sorta like antilock brake. If the wheel locks, speed will go negative, and it will bring back a positive command, then oscillate around there as the robot decelerates. We can also calibrate it to hold an acceleration (by changing the P and I gains and ramp rates) so we don't get slip and twist. It's quite effective. It's not really hard to implement, but it's not totally simple either.


For anything outside of the drivetrain, we usually run some sort of position or speed control, which will hold whatever motor power is needed to do something. Sometimes we use large deadbands on both the I term and output, for example in a device which is running near peak power and can't move at non-100% voltages.