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对存在未知干扰的Lipschitz非线性系统,探讨了基于滑模观测器的执行器故障检测的方法。通过等价状态变换,可以得到2个子系统,其中一个子系统与执行器故障和未知干扰耦合,而另一个子系统则只与执行器故障耦合。在此基础上,提出了一种免受未知干扰影响,可对执行器故障敏感的滑模观测器设计方法。这种滑模观测器可以作为故障检测工具,而将其输出估计误差作为残差发生器,用于执行器故障检测。相比滑模观测器的故障重构方法,该方法大大放宽了对数学假设条件的要求。最后,对一个大攻角状态下的航天器的简化模型进行了数字仿真,仿真结果表明了所提方法的有效性。
For Lipschitz nonlinear systems with unknown disturbance, the method of actuator fault detection based on sliding mode observer is discussed. Through the equivalent state transformation, two subsystems can be obtained, one of them is coupled with actuator failure and unknown disturbance, while the other subsystem is only coupled with actuator failure. On this basis, a design method of sliding mode observer that is sensitive to actuator failure is proposed, which is immune to unknown disturbance. The sliding mode observer can be used as a fault detection tool, and its output estimation error as a residual generator for actuator fault detection. Compared with the fault reconstruction method of sliding mode observer, this method greatly relaxes the requirement of mathematical hypotheses. Finally, a simplified model of a spacecraft at high angle of attack is digitally simulated. The simulation results show the effectiveness of the proposed method.