改进的四陀螺冗余捷联惯组故障诊断与隔离方法

摘要

A combined approach to gyro⁃quadruplet fault detection and isolation ( FDI) is presented, for generalized likeli⁃hood test ( GLT) fails to isolate the faulty gyro in a gyro⁃quadruplet. GLT and optimal parity⁃vector test ( OPT) can only de⁃tect the failure, when there are four gyros, which is a defect of parity space. Wavelet analysis method has multi⁃scale analy⁃sis functions and ability of characterizing local features in time domain and frequency domain. So Wavelet Transform is intro⁃duced to help to isolate the faulty gyro. The effectiveness of the new approach is demonstrated through simulations.%四个陀螺和四个加速度计构成的冗余捷联惯组系统，采用等价空间法———广义似然比法、最优奇偶向量法进行故障诊断与隔离时，会出现不能正确隔离出故障仪表的问题。分析后得出，存在一个余度时，等价空间法只能诊断出故障，而无法隔离故障仪表，这是由等价空间法的原理决定的。小波变换可对信号进行多尺度分析，能够准确地找出信号奇异点———幅值突变和频率突变等。基于以上问题，利用小波变换对突变信号敏感的特性，提出等价空间＋小波变换的组合方法，对四陀螺冗余捷联惯组进行故障诊断与隔离。数字仿真试验证明：对于阶跃型故障，该组合方法能诊断故障并能成功进行故障隔离。