Blowing up in extremes
If you have a lot of abrupt changes in your forces (or hinge angle/speed values) you may get blow ups. For example, this can happen with AI that is being trained and is sometimes noisy.
To solve this, use a low pass filter. A simple way is to average the current value with the last value and pass that as the force or speed:
use output for joint angle/speed/force, whatever.