[Aignam]

Originally Posted by eugenebrooks

We control a single rotating arm with a similar setup. The drive
to the motor is derived from the difference of the values returned
by the pots. This produces a torque on the motor that is proportional
to the error. The result, if you increase the gain to get good precision,
is a harmonic oscillator. If you run in to that, you add a damping force
derived from speed of the arm, calculated by reading its position on two
(or more) successive radio packet cycles between the OI and the RC.
The arm then behaves as a damped harmonic oscillator. With well
chosen damping it won't oscillate at all. Use quality pots that do a good
job of maintaining continuity as they are turned.

Funny story about this. The team was at the Bristol-Myers Squibb shop, and I kept hearing the programmers on our team and the BMS tradesmen talking about "pots", and I couldn't count the times I heard them make references to the "pots", since we were programming the arm. It took me most of the day to figure out that "pots" were potentiometers. Then everything started making sense. Alas, clarity.