Spacecraft Actuator Fault Diagnosis Based on Nonlinear Unknown Input Observer

Abstract

In this paper, we study the fault diagnosis of spacecraft actuators for a class of nonlinear system with Lipschitz constraints. To isolate the faulty actuator from others, we propose a bank of isolation observers to generate the structured residuals. Each isolation observer is designed based on nonlinear unknown input idea of decoupling the actuator fault as disturbance. The robust stability of the observer is analyzed with the Lyapunov theory. Finally, the proposed approach is applied to three-axis stabilized satellite attitude control system, and the effectiveness of the approach is verified for typical faults diagnosis of the satellite actuators.

Keywords

nonlinear unknown input observer / structured residual / actuator / fault diagnosis / satellite attitude control system