Active fault-tolerant attitude control for flexible spacecraft with loss of actuator effectiveness

A theoretical framework for active fault-tolerant attitude stabilization control is developed and applied to flexible spacecraft. The proposed scheme solves a difficult problem of fault-tolerant controller design in the presence of severe partial loss of actuator effectiveness faults and external disturbances. This is accomplished by developing an observer-based fault detection and diagnosis mechanism to reconstruct the actuator faults. Accordingly, a backstepping-based fault-tolerant control law is reconfigured using the reconstructed fault information. It is shown that the proposed design approach guarantees that all of the signals of the closed-loop system are uniformly ultimately bounded. The closed-loop performance of the proposed control strategy is evaluated extensively through numerical simulations.