Design of speed controllers to suppress torsional vibrations based on frequency characteristics

In this paper, frequency characteristics of speed controllers to suppress torsional vibrations of the mechanical system are investigated. Straightforward design methods of controllers based on the frequency characteristics are proposed. The methods are easily applicable to practical servo drive systems with inner torque control loop whose frequency bandwidth is not wide enough compared with the resonant frequencies, the second order mechanical resonant modes and so on. The validity of this methods is confirmed by computer simulations and experiments.