What constants are u using for high velocity PID

[Salik Syed]

What constants for P I and D? I got it to somewhat work but its velocity was always too high... i know i could further test more values but i tried all day and now i am at home and have no access to the robot, i desparately need some values that i can try out... our custom PID code is totally screwed up and i might port over watsons but i need a start point well...... this turning into a rant...

thanks for any help

[Paul Copioli]

Try tuning it without I. A PD loop will be fine for high speed velocity. You are, more than likely, getting fast Integration error build up. We are not using I and we are right on target for both wheels. At high speed, the P gain is very sensitive so you will need to really play with D a lot more than if you were tuning a drive train.

[steven114]

Also make sure that your terms are sensible - I had problems when my P term overflowed when the error was large enough. If the signs are wrong, then you'll find all kinds of problems...

[Jared Russell]

I had a P of 70, a D of 30, and an I of 3, all divided by a divisor of 10. That's with a 16 CPR encoder on the shaft.

Snaps right to the setpoint.