Gimbal angular servo system of CMG using active disturbance rejection control

The gimbal angular servo system for a Control Moment Gyroscope (CMG) directly driven by a Permanent Magnet Synchronous Motor (PMSM) was designed, and an Active Disturbance Rejection Control (ADRC) algorithm was proposed to control the gimbal angular position command. Firstly, the mathematic model for the CMG gimbal angular servo system was built by using id=0 filed oriented control strategy. Then the effects of disturbing torques on the performance of gimbal servo system were analyzed, and a simulation system for gimbal servo system by using the ADRC as a position loop was built up in Matlab. Finally, the hardware experiment of ADRC algorithm was carried out. Tests and experiments show that the maximal position error is 0.01 rad and the steady state speed is 0.099 rad/s when a k=0.099 position curve is tracked by the ADRC. Moreover, the relative amplitude error is 0.05% and the phase error is 0.0018 rad when the gimbal angular servo curve 7.63238-2 cos(t) rad is tracked by the ADRC. The proposed gimbal servo system of CMG satisfies the demands of high precision and robustness.