PIDController tuning

[Kevin Sevcik]

Originally Posted by engunneer

fit is really handy if you can have it graph position in real time. Tell it to do a step move (say from 100 to 150 degrees) and see the shape of how it gets from one to the other. If it doesn't get to exactly the right point, make I smaller (more powerful). If overshoots too far, make P smaller (weaker).

I believe you mean to make I larger. The PIDController class multiplies the integrated error by I, so larger I means stronger integral action.

Also, changing battery voltage will change the performance of your PIDController unless you're using a CANJaguar in Voltage Mode, which would add another bit of control action in the Jaguar itself which might confuse things. The reason is that all speed controller commands are in percentage of battery voltage. Higher battery voltage means stronger motor action, which is the equivalent of turning up all your gains slightly. To compensate for this, your best option is to tune with a freshly charged battery and no other systems running. If your system is stable under these conditions, it will most likely be even more stable as battery voltage drops under load during a match.