Abstract: The attitude control system constructed by a cluster of control momentum gyro (CMG) is the best choice to meet the rapid attitude maneuvering and accurate control requirements of today’s agile satellites. Meanwhile, the control accuracy, response speed as well as stability of the gimbal control assembly determine the CMG performance directly. Focusing on the high performance requirement for agile satellites, a high performance gimbal control method is proposed, by employing the permanent magnetic synchronous motor (PMSM) with the field oriented control (FOC) algorithm, and utilizing a gimbal rate observer to drive the gimbal mechanical assembly directly in this paper. In order to solve the problem that the resolving rate of normal angular sensors are difficult to meet the accuracy requirement, a Luenberg state observer is introduced to obtain the observed gimbal rate value in the extremely low rate condition. The observed value is introduced into the closed loop system of gimbal rate thereby. Theoretical analysis and simulation experiments have proved the validity of the proposed method. Then, a simulation work is done to aim at studying the effect of motor parameter drifting on the observed value. The simulation results have demonstrated the robust performance of the proposed observer based closedloop rate control system.

Key words: control moment gyro, gimbal, PMSM, observer