Robust actuator fault estimation for satellite control system via fuzzy proportional multiple-integral observer method

In this paper, a novel actuator fault estimation scheme based on T-S fuzzy proportional multiple-integral (PMI) observer is developed for satellite attitude control system (ACS). The nonlinear dynamics of ACS is represented by T-S fuzzy model. Then the actuator fault and its derivative are introduced as an augmented state. Fuzzy proportional multiple-integral observer is designed to estimate both the system state and the actuator fault simultaneously and directly. The method is proved to be suitable for soft fault diagnosis. Robustness issue is considered with respect to input disturbance in the satellite system. The effectiveness of our proposed fault diagnosis is demonstrated through numerical simulations.