How to convert angles to motor speed

[johnwasser]

@amad3v

2: Why the output of the first PID system is rotational rate and not angles? Is it because of the derivative term?

I think the Output of the first PID system is an angular rate of change. The Setpoint and Input of a PID must be in the same units. The output of the rate gyro (Input to the next PID) is an angular rate of change so the Setpoint has to also be an angular rate of change.