How can I compute new pid coeff from old ones based on

[JulienDevillers]

Hello

I'm driving the pwm of an electric motor with a pid controler. It works pretty well.

After some testings, I realized that the fact that the motor is powered by a battery makes the system behave differently depending on the battery voltage.

I will change the system in order to make the pid system control the voltage provided to the motor instead of the pwm ; another system will do the conversion V -> PWM based on the battery voltage. Therefore, I expect the same behaviour whatever the battery voltage (if of course, the pid does not ask for a voltage more than battery voltage)

Concretely, PID will not control values from 0 to 20k (pwm period) but 0 to 8400 (mV).

My question is: Is there a mathematical way to compute the new PID coefficients from the old ones to get the same behaviour with the new actuator without having to go again to a new pid tuning session?

Thanks.