基于改进距离相似度的故障可分离性分析方法

Fault isolability analysis based on improved distance similarity

为了定量分析故障分离的难易程度,提出基于改进距离相似度的故障可分离性分析方法。以基于等价空间的故障诊断残差产生器为例,根据不同故障引起残差向量在概率分布上的差异建立改进故障分离条件,利用残差向量的距离相似度和方向相似度评价故障分离的难易程度,提出基于改进距离相似度的故障可分离性定量评价指标。通过仿真试验分析某固定翼无人机纵向飞行控制系统的故障可分离性。结果表明:该方法能够准确判断故障分离条件,定量分析系统进行故障分离的难易程度,与现有方法相比,改进故障分离条件更为直观,基于改进距离相似度的故障可分离性评价指标能够实现残差向量在距离差异和方向差异的综合评价。

A fault isolability analysis approach based on improved distance similarity was proposed to evaluate quantitatively the difficulty level of fault isolation. A parity space-based fault diagnosis residual generator was taken as an example, and the improved fault isolation condition was constructed based on the difference of the residuals in probability distribution. Then the distance similarity and direction similarity of residuals were adopted to evaluate the difficulty level of fault isolation, and the quanlitative evaluation index of fault isolability was put forward. A simulation was carded out to analyze the fault isolability of a fixed-wing unmanned aerial vehicle longitudinal flight control system. The results demonstrated that the method could decide accurately the fault isolation condition, and evaluate quantitatively the difficulty level of fault isolation. The improved fault isolation condition was more intuitional, and the evaluation index could evaluate comprehensively the difference of residuals in both distance and direction compared with existing approaches.