Finite-time fault-tolerant output feedback attitude control of spacecraft formation with guaranteed performance

This article examines the problem of finite-time fault-tolerant output feedback attitude control for spacecraft formation system with guaranteed performance, in the presence of uncertainties, external disturbances, actuator faults, and input saturation. First, a neural network (NN) based finite-time observer is established for follower spacecraft to observe its angular velocity, where the NN is utilized to approximate the unknown uncertainties. Furthermore, based on the information from the angular velocity observer, backstepping procedure, and barrier Lyapunov function technique, a distributed finite-time controller with only attitude measurement is proposed. Unlike the existing finite-time control scheme, the tracking errors keep inside their predefined feasible regions with guaranteed transient and steady-state performance. A theoretical proof shows that the finite-time stability of the closed-loop system can be achieved. Finally, numerical simulation results are presented to illustrate the effectiveness and fine performance of the proposed finite-time observer and controller for the attitude control system.