You guys are suggesting PID?!?!
K.I.S.S. 237's arm works off a P loop with a "gain" of 1. If it needed to be more complex it would be, but we found that theres more or less no overshoot or oscillation with this system.
First lets make sure the path of least resistance is closed (open, if you want to use electrical terms
) before we suggest complex closed loop control theory.