非线性系统执行器故障检测及重构

针对受到外部干扰的利布希茨非线性系统,讨论了一种观测器匹配条件不满足下的基于观测器的执行器故障检测方法.通过构造辅助输出,使得匹配条件针对该辅助输出得以满足;通过一高阶滑模观测器,不仅估计出辅助输出,还估计出它的微分.基于高阶滑模观测器,提出了一种执行器故障重构的方法.通过引入一个自适应调节项,对利布希茨常数进行自适应性调节,从而设计中无需知道利布希茨常数的大小.最后通过一个3阶系统的仿真,表明了方法的有效性.

Actuator fault detection and reconstruction for nonlinear systems

Abstract: In this paper, the problems of the actuator fault detection and reconstruction based on observers are discussed for uncertain nonlinear systems, when the observer matching condition is not satisfied. An auxiliary output vector is introduced so that the observer matching condition is satisfied. A high-order sliding mode observer is considered to get the exact estimates of both the auxiliary outputs and their derivatives in a finite time based on the system measured outputs. A kind of fault reconstruction method based on the high-order sliding mode observer is developed. In the design, the Lipschitz constant can be unknown because an adaptive controller is implemented to adjust it adaptively. Finally, a numerical simulation example is given to illustrate the effectiveness of the proposed methods.