Third-order sliding mode fault-tolerant control for satellites based on iterative learning observer

The attitude fault-tolerant control problem for a satellite with reaction-wheel failures, uncertainties, and unknown external disturbances is investigated in this paper. Firstly, an iterative learning observer (ILO) is proposed to achieve fault detection, isolation, and estimation. Secondly, based on the ILO, a third-order sliding mode controller is proposed to stabilize the satellite attitude rapidly under unknown external disturbances and reaction-wheel faults. Thirdly, the asymptotically stability of the ILO and the third-order sliding mode controller is proved by using the Lyapunov stability theory. Finally, simulation results demonstrate that the proposed control scheme is more effective and feasible by comparing with other fault-tolerant control approach.