一种改进的Willsky广义似然比故障检测方法

在对线性闭环动态系统应用Ｗｉｌｌｓｋｙ广义似估比法进行故障诊断，跳跃型故障信息在输出检验序列中是以相对低频的形式存在的。运用数字滤波器算法滤除广义似然比值序列中高频成份，并以滤波输出值的大小为依据，判定系统所处的状态。仿真表明，在数据窗宽度较小的情况下，能取得较高的故障诊断能力，从而提高检验的快速性和准确性。

An Improved Willsky Generalized Likelihood Ratio Method for Fault Detection

The GLR method in 1976 paper by Willsky et al[1] is still in use with only some improvements made here and there. The authors, going somewhat beyond the research areas of their interest, arc very pleased to find that concepts in signal processing can be fruitfully applied to improving the GLR method.The irnprovcrncnt, bclicvcd to be quite important, depends mainly on the authors' understanding that the process involved in computing GLR of Willsky can be considered as signal processing with a fault matching filter and then a square detector.The simplified model of an actual control system of a flight vehicle is taken as example. GLR sequence is computed with the method of Willsky and also with the authors' improved method. Digital results arc given in Figs.2(Willsky) and 3(authors) respectively. It can be easily seen that faults can be more clearly dctcctcd with the authors' method, even though amount of computation needed is less by 50% compared with the traditional GLR method of Willsky.