Robust speed control of DC servo motor based on Lyapunov´s direct method

The speed control ability of a DC servo motor is affected by parameter variations and disturbance torque. In this paper, the robust speed control method of a DC servo motor with a disturbance torque observer is proposed, in which the disturbance torque observer is used for the compensation of parameter variations and disturbance. The influence of estimation error is restrained by feedback gain based on Lyapunov´s direct method. Also, the current tracking control is very important, since motor torque is generated by the armature current. The robust current control method of a voltage source PWM inverter with a disturbance voltage observer is presented; the armature current is controlled to be exactly equal to the reference current under the variations of load parameters and operating conditions