PID How to hold an arm in a fixed position without a locking gear box

[Donut]

Make sure to set the victor your motor is hooked up on to the "brake" setting; this will make it more difficult to back drive and will make the motor better keep your current arm position.

Also, the type of system you use to move your arm can automatically help keep your arm stable. Screw drives are basically impossible to backdrive, but you're limited to less than 180 degrees of rotation with them.

Using some of these things may make it unnecessary to keep a PID loop in programming monitoring the position of your arm.