Tuning a PIDF follower on a robot with high gearing
One of the problems we have been encountering during the off-season is tuning a PIDF follower reliably on our 2017 robot. It is geared with a fairly high theoretical top speed (~17fps), and our autonomous trajectories are generated with a maximum velocity of about 5fps. This means there isn't much torque at the wheels compared to resistive forces.
Without feedback terms, velocity does not track well. Generally a kV and kA value that work at faster speeds (4-6fps) are inadequate for slower speeds (2-3fps). We can add in feedback, but a few things happen:
1) The Kp term does more corrective work than it should be doing
2) Because of the large error, following is inconsistent between different trajectories
How do teams overcome this inconsistency at lower torque and get better tracking with feed-forward terms before moving on to adding feedback terms?