具有时变时滞的线性离散随机系统的间歇故障检测

Intermittent fault detection for linear discrete-time stochastic systems with time-varying delay

针对一类具有时变时滞和外部未知扰动的线性离散随机系统,研究了其间歇故障检测问题.考虑一类具有周期性的时变时滞,利用提升技术和叠加原理将线性时变时滞系统转化为线性时不变系统.基于等价空间法设计对外部未知扰动解耦的结构化标量残差,在此基础上,通过残差统计特性分析和给定的显著性水平设定检测阈值.利用两个假设检验分别检测间歇故障的发生时刻和消失时刻,并分析了间歇故障的可诊断性.最后,仿真结果验证了该间歇故障检测方法的有效性.

The problem of intermittent fault detection is investigated for a class of linear discrete-time stochastic systems with time-varying delay and unknown disturbance.By using the lifting technique and superposition principle,the linear discrete-time system with time-varying delay is transformed into a linear discrete time-invariant system.A structured scalar residual decoupled from the unknown disturbance is designed by means of the parity space method,and the detection thresholds are set based on the analysis of residual statistical properties and given significance levels.Moreover,the appearing time and disappearing time of the intermittent fault are detected through two hypothesis tests,and the diagnosability of the intermittent fault is analyzed.Finally,the effectiveness of the proposed method is illustrated by the simulation results.