Observer-Based Backstepping Fault-tolerant Control for Spacecraft with Reaction-wheel Failures

In this paper, nonlinear satellite system with actuator faults is considered. To solve the problem of attitude stabilization of satellite under external disturbances and actuator faults, an observer is designed firstly. And the output of the observer is proved to be uniformly ultimately bounded. By using the estimated information of the observer, a backstepping fault-tolerant controller is derived. The proposed controller could achieve attitude stabilization in the presence of actuator faults. Finally, a simulation of attitude stabilization is carried out to illustrate effective of the fault-tolerant controller.