多小波在振动信号降噪中的应用

Application of Multi-wavelet in Vibration Signal Denoising

发动机是一个复杂的机械动力系统,为了通过振动信号来判断发动机的状态,可通过传感器采集发动机振动信号,进行故障诊断,必须对其原始信号进行降噪预处理。传统的小波降噪一般选取单小波,由于多小波可同时具有正交性、紧支撑性、对称性和高阶消失矩特性,比单小波更具优势。针对GHM多小波降噪,讨论了两种预处理方法;对仿真信号分别进行了多小波、db4小波软阈值降噪,实验结果表明多小波具有更好的降噪效果;最后将多小波应用于飞机发动机振动信号降噪中,取得了良好效果,为发动机状态监测与故障诊断提供了一种可行的信号处理方法。

As engine is a complex system of mechanical power,in order to determine the status of its fault diagnosis by the vibration signal,vibration signal must be pre-processed by denoising.Traditional wavelet denoising generally select a single wavelet,due to multiwavelet has orthogonality,compact support,high-order vanishing moments and symmetry at the same time,which has more advantages than a single wavelet.This paper by using GHM multiwavelet in signal denoising,discussed two kinds of preprocessing methods.Compared with db4 single wavelet,the result shows that multiwavelet is better in soft threshold denoising.Finally multiwavelet was used in aircraft engine vibration signal denoising and achieved good result.It provides a viable method of signal processing for the engine condition monitoring and fault diagnosis.