基于有限时间未知输入观测器的一类受扰非线性系统故障检测与估计

针对一类非线性系统同时存在执行器故障、传感器故障和扰动的问题,提出一种基于有限时间未知输入观测器的故障检测与估计方法.首先,通过线性非奇异变换将原系统解耦为两个降阶的子系统,其中一个子系统只包含扰动,另一个子系统同时包含扰动和故障;然后,通过一阶低通滤波器获得新的状态并与子系统构成增广系统,实现将原系统的传感器故障转化为增广系统的执行器故障;接着,设计未知输入观测器对增广系统故障进行检测,实现在有限时间内估计出系统的扰动和故障,并通过理论分析验证所设计观测器的有限时间收敛性;最后,基于永磁同步电机(PMSM)转速系统进行仿真研究,仿真结果验证了所提出方法的有效性.

Fault detection and estimation for a class of disturbed nonlinear systems based on finite-time unknown input observers

For a class of nonlinear systems where actuator faults, sensor faults and disturbances exist simultaneously, a fault detection and estimation method is proposed based on finite-time unknown input observers in this paper. Firstly, the original system is decoupled into two reduced-order subsystems by linear nonsingular transformation, and one subsystem contains only disturbances, and the other subsystem contains both disturbances and faults. Then, new states are obtained by the first-order low-pass filters and the augmented system is formed with the subsystem, which can transform the sensor faults of the original system into the actuator faults of the augmented system. The unknown input observers are designed to detect the faults of the augmented system, and the disturbances and faults of the system can be estimated in finite time. The finite time convergences of the designed unknown input observers are proved by theoretical analysis. Finally, the simulation study is conducted on the permanent magnet synchronous motor (PMSM) speed system, and the simulation results verify the effectiveness of the proposed control method.