Adaptive Backstepping Based Fault Tolerant Spacecraft Attitude Control Under Loss of Actuator Effectiveness

In this paper, an adaptive backstepping technique based fault tolerant control scheme is developed for a spacecraft attitude stabilization system, in which the external disturbances and partial loss of actuator effectiveness fault are considered. More specifically, using the adaptive backstepping control method, a baseline control law is first proposed for the normal system without actuator fault; then this is extended to the faulty system by adding an auxiliary system, which is used to compensate the actuator fault by designing the control input of the auxiliary system such that the output of the auxiliary system can follow the specified commands of the normal system. As motivated from practical spacecraft control applications, synthesis of controller in the presence of faults with no knowledge of fault time, pattern and value. Complete stability and performance analysis are presented and illustrative simulation results of an application to spacecraft attitude control show that the high precise attitude control is successfully achieved using various scenarios of partial loss of control effectiveness induced by actuator failures.