PIDController Parameter values for QuadEncoder

[robotsteve]

We are using Java with USDigital Quad Encoder E4P 360-250 -D-H-D-B
on a Innovation First Victor 884 motor controller

Using the PIDController class and QuadEncoder class and Victor clas
and are having problems getting the PID coefficients and period
to get reasonable action of the speed control.

We have the prototype up on blocks -- ie the wheels just spin without resistance, so weight at this point isn't relevant. We estimate the wheels spin at about 10 rev's a second.

The last values we used are:
public static double P_DRIVE_CONST = 0.12;
public static double I_DRIVE_CONST = .07;
public static double D_DRIVE_CONST = 0;
but we have experimented with P over a very wide range.

Do we need to have the robot actually on the floor so the motors
react to inertia and resistance?

Thanks-
Steve

[Alan Anderson]

Originally Posted by robotsteve

Do we need to have the robot actually on the floor so the motors
react to inertia and resistance?

In a word, yes.

You could perhaps make some sort of dynamometer setup so you can keep the robot itself stationary. We've occasionally talked about doing that, building a fixture to put other wheels in contact with the robot wheels, backdriving a gearbox into a motor with an electrical load on it.