Abstract:In this paper, a fault-tolerant control design method is proposed for the rigid satellite attitude systems with external disturbance and actuator faults by using sliding mode control scheme and nonlinear observer technique. Firstly, the satellite attitude systems’ kinematic equations and dynamic equations with external disturbance and actuator faults are given. Then, a nonlinear observer is given to obtain the estimate value of actuator faults. Based the fault estimate information, a fault-tolerant controller is designed in the framework of sliding mode control. Meanwhile, the Lyapunov theory is used to analyze the stability of the closed-loop attitude systems. Finally, simulition results are given to illustrate the robustness and effectiveness of the developed fault-tolerant control scheme.