基于包络切片谱和时频谱的轴承故障诊断

Bearing fault diagnosis based on enveloping slice spectrum and time-frequency spectrum

为了有效提取轴承故障信号的故障特征以及更好地显示其时频特性,提出了基于局部均值分解(LMD)的包络切片谱分析及时频分布方法。首先,使用LMD对轴承故障信号进行分解得到一组PF分量。然后,对各PF分量的包络信号(瞬时幅值)进行切片谱分析。同时,由PF分量的瞬时频率和瞬时幅值获得各PF分量的时频分布。实测轴承故障信号的LMD包络切片谱分析及时频分布结果表明,LMD包络切片谱可准确获得内圈故障轴承和外圈故障轴承的故障特征频率,LMD时频分布可更直观地显示轴承故障信号的时变瞬时特性,可用于辨别轴承的故障形式。

In order to extract the characteristics of bearing fault signals effectively and to display their time-frequency characteristics better,a method of enveloping slice spectrum analysis and timefrequency distribution based on local mean decomposition（ LMD） was proposed. Firstly,LMD was used to decompose bearing fault signals into a set of PF components. Secondly,slice spectrum analysis was implemented for the enveloping signal（ instantaneous amplitude） of each PF component. Meanwhile,the time-frequency distribution of each PF component was obtained through its instantaneous frequency and instantaneous amplitude. The results of the LMD enveloping slice spectrum analysis and time-frequency distribution of the measured bearing fault signals demonstrate that LMD enveloping slice spectrum can accurately gain the fault characteristic frequencies of the inner ring fault bearing and outer ring of a fault bearing,and LMD time-frequency distribution can display the time-varying and transient characteristics more intuitively, which can be used todistinguish the fault forms of bearings.