A combination control to suppress flexible vibration of complex spacecraft

For the complex spacecraft with large flexible accessories, suppressing the flexible vibration is a significant problem. Based on singular perturbation theory, the combination control method is proposed, which associates nonlinear PID controller and linear quadratic controller by dividing spacecraft dynamics equations into slow-change subsystem and quick-change subsystem. The slow-change subsystem stabilizes the attitude motion of center rigid body by adopting nonlinear PID control law; and the quick-change subsystem suppresses the vibration of flexible accessories by adopting a linear quadratic control strategy. Simulation results show that this method can guarantee the stability of the spacecraft while suppressing the vibration of flexible accessories, which significantly improves the performance of the attitude control system.