Fault estimation and fault tolerance control for spacecraft formation systems with actuator fault and saturation

In this study, a novel fault estimation and fault tolerant control (FTC) scheme is proposed for a class of nonlinear spacecraft formation flying systems in actuator fault and saturation case, in which the directed communication topology with leader spacecraft as the root. The decentralized unknown input observer is designed to estimate the unknown actuator fault factors, which affect the performance of spacecraft formation flying systems. The obtained fault estimated values are served as the design of distributed fault tolerant formation controller. Then, a distributed fault tolerant formation control algorithm is proposed using adaptive terminal sliding mode control (ATSMC) technique, such that each follower spacecraft could synchronize with leader spacecraft in the presence of actuator fault and saturation case. Finally, the effectiveness of the proposed FTC scheme is verified by numerical practical examples.