Integrated fault tolerant attitude control approach for satellite attitude system with sensor faults

Summary In this study, a novel integrated fault tolerant control (FTC) strategy is proposed for a rigid satellite attitude systems under the case of external disturbance, Lipschitz nonlinearity, and sensor faults. Different from the traditional adaptive fault estimation method, an augmented fault estimation observer is designed for the considered faulty satellite attitude system, which could be used for estimating both system state and sensor fault. A virtual observer is firstly introduced, and then, a real observer is derived as a result of the unmeasurable information to be used for the design of the virtual observer. On this basis, an integrated FTC approach is developed for the considered faulty satellite attitude system by combining backstepping control and fractional order nonsingular terminal sliding mode control techniques, such that the closed‐loop system not only has good robustness to external disturbance but also has better fault tolerance capability to unknown sensor fault. Finally, a simulation example is provided to demonstrate the feasibility and advantage of the proposed FTC scheme.