Active fault detection for spacecraft attitude control system

This paper proposed an active fault detection (AFD) method to detect the incipient fault occurred in the spacecraft system. Since there's no abnormal change in the characteristic of the incipient fault system, AFD can be carried out by injecting a designed excitation signal into the system to activate the minor fault signature. Based on the Youla parametrization, the closed-loop residual signal and the performance criteria are constructed. Then the excitation signal of AFD is optimized to not only realize incipient fault detection, but also affect the system as little as possible. What's more, the residual evaluation function and the threshold are designed to guarantee the robustness of the proposed AFD method to the external disturbances, which can prevent the false alarms and omission of the incipient fault. The comparative simulations are carried out to verify the efficiency of the proposed method.