Robust fault reconstruction design for satellite attitude control systems based on proportional integral observer

The problem of observer-based robust actuator fault reconstruction in the satellite attitude control system (ACS) is investigated. Firstly, a discrete-time model for satellite ACS subject to space disturbance torques and measurement noises is established. Secondly, a discrete proportional integral observer (PIO) is constructed to simultaneously estimate satellite attitude angles and attitude angular velocities, and the current fault reconstruction signal is further updated by its previous information and output estimation error. Thirdly, based on the disturbance-decoupling methodology, the proposed PIO is partially decoupled from space disturbance torques, and then the PIO is designed to attenuate the influence of the remaining part of space disturbance torques and measurement noises via H_∞ technologies. In addition, observer gain matrices are conveniently computed using standard linear matrix inequality tools. Finally, simulation results validate the effectiveness of the proposed PIO-based fault reconstruction approach.