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:

output=0.5*(last_value+desired_value);
last_value=output;