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Originally Posted by ConKbot of Doom
You would almost undoubedly have to use some form of a PID routine, a set rate of rotation would make for nasty oscilations when it got to the point.
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Surprisingly, a PID control system is not necessarily required. I know others can elaborate on what I am saying, but to keep it simple: PID control includes a form of speed, or distanced traveled, feedback to help regulate speed and positioning. This is a valuable additions to positioning control, but is not required. Simply comparing the controller's position to the robot's arm, or which ever axis your controlling, and using the difference to drive a motor will work. Yes, there are some obvious drawbacks, but as for speed limiting, that can simply be done in the position comparing function.
As ConKbot said, just using a set rate will lead to oscillations, especially when just moving a small distance. But, if you compared the controller position to the controlled axis position, you would see that as you got closer to the desired position, the axis would slow down and make the possibility of oscillating much less.
There are many factors that play into the success you will have with position feedback control like: mass being moved, friction in the system, moment of inertia, system speed etc. If you find that your system oscillates, then you will want to replace your simple comparative function with a PID function which will allow tuning of your axis control. Otherwise, it may not be necessary.