强抗噪时频分析方法及其在滚动轴承故障诊断中的应用

Noise-resistant Time-frequency Analysis Method and Its Application in Fault Diagnosis of Rolling Bearing

根据滚动轴承发生故障时呈现出循环平稳的特征,将基于二阶循环统计量的谱相关或谱相关密度分析方法加以改进,提出一种新的时频分析方法。经仿真验证,所述方法相对于谱相关分析方法具有很强的抗噪能力;针对轴承发生故障时的调制特征,往往只需要提取出故障频率即循环调制频率而不必提取调制现象的载频,在所述方法的基础上,将其加以改进,改进后的谱分析方法只提取出调制频率,通过滚动轴承三种故障试验(内、外圈故障及滚动体故障)验证了其具有更清晰的表达效果和更好的故障特征提取效果。

Based on the property of cyclostationarity when fault arises in rolling bearing, The spectrum correlation （SC） or spectrum correlation density （SCD） based on second order cyclic statistic is improved and a new time-frequency analysis method naming improving spectrum correlation （ISC） is proposed. The improved method has the advantages of higher noise-resistant advantages over SC. It usually takes on modulation phenomenon when fault arises in rolling bearing, and the aim of fault diagnosis is to extract the fault characteristic frequency or cyclic modulation frequency only and neglect the modulated frequency or carrier frequency, so the ISC method is improved further and the integrated improving spectrum correlation （IISC） is proposed. The IISC extract the modulation frequency only which has the advantages of clearer expression effect and much better extraction effect. The above stated is verified through rolling bearing＇s three fault types （inner race fault, outer race fault and ball fault）.