INTEGRATED FAULT ESTIMATION AND FAULT-TOLERANT CONTROL FOR RIGID SPACECRAFT ATTITUDE SYSTEM WITH MULTIPLE ACTUATOR FAULTS

摘要

This paper proposes an integrated fault estimation and fault-tolerant control (FE/FTC) method for a rigid spacecraft attitude system in the presence of multiple actuator faults. The proposed scheme solves a problem of fault-tolerant controller design in the presence of actuator loss of effectiveness (LOE) fault, bias fault, uncertainties and external disturbances. Firstly, an adaptive sliding mode fault estimation observer is designed for the faulty rigid spacecraft attitude system to get the estimated values of actuator faults under the existence of unknown inertia matrix uncertainties and external disturbances. Then, an integrated FE/FTC attitude control strategy is developed by using both fractional-order nonsingular terminal sliding mode (FONTSM) method and backstepping technology, and it could guarantee that the attitude error variables of faulty closed-loop attitude system are stable within a finite time. Finally, simulation results are presented to demonstrate the effectiveness of the proposed technique.