Active Fault Tolerant Control Scheme for Satellite Attitude Systems: Multiple Actuator Faults Case

In this paper, an active fault tolerant control (FTC) design approach is proposed for the satellite attitude systems with exogenous disturbance and multiple actuator faults. Firstly, the nonlinear attitude system model of rigid satellite with multiple actuator faults is given. Next, an actuator fault diagnosis scheme, including a fault detection module and a fault estimation module, is given so as to detect the time of unknown actuator faults occurred and obtain their estimation values. Then, a terminal sliding mode-based fault tolerant attitude controller is designed using backstepping control technique, which guarantees that the closed-loop attitude systems of rigid satellite are asymptotically stable in the presence of multiple actuator faults. Numerical simulations illustrate the good performance of active FTC proposed in this study.