Abstract: To avoid the singularity of control moment gyroscopes, a system consisting of three orthogonally mounted scissor pairs of control moment gyroscopes is employed as an actuator for spacecraft attitude control. An accurate mathematical model of spacecraft attitude motion manipulated by the gyroscope system is derived on the basis of Newton-Euler method. On this basis, a nonlinear control law is designed for the spacecraft to implement large-angle attitude maneuvers. In the design process, the stability of the attitude control system is proved. Singularity analysis of the gyroscope system shows that there exists no inner singularity in this system. A pseudo inverse control law is proposed for keeping the gimbal angles of each scissor pair of gyroscope synchronous. To improve the synchronization performance and the anti-disturbance ability of the system, an adaptive nonlinear feedback controller is designed on the basis of stability theory of Lyapunov. Simulation verifies the validity of the designed control laws and manipulation law, as well as the capability of the gyroscope system in driving the spacecraft to implement large angle attitude maneuver.

Key words: Attitude control, Control moment gyroscope, Nonlinear control, Synchronization, Spacecraft