Active Fault Tolerant Control Design for Satellite Attitude Systems with Mixed Actuator Faults

This paper consider the active fault tolerant control (FTC) design problem of a rigid satellite attitude systems with parameter uncertainty, external disturbance and mixed multiple-type actuator faults. A functional observer-based fault detection scheme is proposed to monitor the time of unknown faults occurred, it could realize the decoupling between the detection residual signal and the generalized perturbation signal. An adaptive fault estimation observer is designed to obtain the estimated magnitude of unknown actuator faults. On this basis, an active fault tolerant attitude control approach is developed by using integral sliding mode control technique to guarantee that the attitude angles and angular velocities could achieve finite-time convergence in actuator fault case. Finally, the simulation results are given to demonstrate the feasibility of the proposed FTC scheme.