Spacecraft Actuator Fault Diagnosis Based on Nonlinear Unknown Input Observer
摘要: 针对一类满足Lipschitz条件的非线性系统,设计了一组非线性未知输入观测器,并依据故障解耦的思想,产生结构化的残差集,实现非线性系统执行器的故障隔离。研究考虑了未知扰动对非线性系统的影响,并利用Lyapunov理论证明了所设计观测器的稳定性。最后,以三轴稳定卫星的姿态控制系统为对象,仿真验证了所提方法对各种典型执行器故障诊断的有效性。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.