A novel active fault-tolerant control for spacecrafts with full state constraints and input saturation

Abstract

This paper proposes an active fault-tolerant control (AFTC) system for spacecrafts subject to model uncertainty, external disturbance and actuator fault simultaneously. Fault diagnosis is implemented by a robust fault observer with a simple structure. The observer can separately estimate the fault in the existence of disturbance and uncertainty. The influence on observation performance from disturbance and uncertainty is attenuated by linear matrix inequality (LMI) optimization. For the fault-tolerant controller, asymmetric barrier Lyapunov function and backstepping method are used to constrain all the states. Meanwhile, the control input is restricted by a saturation function. Validation and comparative simulations are implemented to demonstrate the proposed AFTC method.