Velocity-based PID with the WPILib PIDController Class

[Mr. Lim]

Originally Posted by Mike Copioli

You are correct. I was giving him an example of positional PID. The math is the same except that the product of K*error is added to the previous throttle. My mistake.

Which in effect would give you an "I" term in your control loop, since I is essentially a scaled accumulation of error?

Thanks for all the responses.

We retuned our PID loop, and started with an I-only control loop, and got it working nicely. There is a bit of integral windup that causes some overshoot when we rotate about our axis, but we can now hit our setpoints. We'll probably try and tweak by limiting the amount of I-accumulation to prevent large wind-up.

Right now however, it drives pretty nicely, but we may tweak at a later date but doing some similar to what Mike Mahar suggested.

We might implement a simple open-loop joystick -> motor algorithm, then add to that the outputs of a PID loop that calculates a delta to get us to our set points.

After doing some research, it sounds like this type of "feed-forward" implementation is popular in velocity-based control applications.

Does anyone else do it this way?