基于SWT与等价空间的LDTV系统故障检测

摘要

This paper deals with fault detection (FD) for linear discrete time-varying (LDTV) systems by combining stationary wavelet transform(SWT)with parity space based method,so as to improve the FD performance. By employing SWT to filter the residual generated with low order parity relation,the design of residual generator can be formulated as multi-objective optimization problem at each scale of SWT, so that minimum ratio criterion of robustness to unknown input and sensitivity to faults are assured,and a bank of multi-scale residuals are obtained by applying the SWT recursive algorithm. Moreover, by analysing the generated residual signals at multiscale, the faults within a broader frequency band can be detected and a lower miss detection rate can be achieved. Finally,a numerical example is given to verify the effectiveness of the proposed approach.%为提高基于等价空间的线性离散时变(Linear discrete time-varying,LDTV)系统故障检测的检测性能,本文提出一种基于平稳小波变换(Stationary wavelet transform, SWT) 与等价空间的LDTV 系统故障检测方法.通过引入SWT 对基于低阶等价关系构造的残差进行多尺度滤波,将残差产生器设计转化为不同尺度下的多目标最优化问题,保证了各尺度下残差对干扰鲁棒性和对故障灵敏性指标的最小化,同时利用SWT 快速算法获得一组多尺度残差信号.进一步,对产生的多尺度残差信号进行多分辨率分析,从而实现较宽频率范围内故障信号的检测,有效降低了故障漏报率.最后,通过仿真实验验证了本文方法的有效性.