Abstract: Deficient capability of disturbance torque attenuation restricts further improvements on the speed control performance of control moment gyro gimbal servo system. Based on the analysis of the disturbance torque and its influences, a terminal variable structure controller combined with disturbance observer was proposed. Utilizing the characteristics of invariance and fast response of the variable structure controller, high precision control was realized under the condition of disturbance torque fluctuations especially high frequency disturbance torque fluctuations. Simulation results show that the proposed method is feasible and efficient. Comparing with the proportional integral derivative controller, the speed fluctuating quantity decreases more than 2/3.

Key words: Control moment gyro, Servo system, Disturbance, Variable structure control, Space actuator