循环统计量方法在滚动轴承故障诊断中的应用

为了处理滚动轴承故障振动信号中的调制现象，利用循环统计理论，分析了二阶统计量循环自相关函数和循环谱密度的特性。基于故障调幅信号模型推导出循环自相关函数的解调原理，指出调幅信号各成分在循环谱密度中的分布频段，提出在循环频率域中提取调幅信号的调制源的方法。该原理和方法通过仿真信号进行验证，应用于滚动轴承的内、外圈及滚动体的故障诊断，有效地提取出故障特征频率。

Application of Cyclic Statistics to Fault Diagnosis of Rolling Bearings

The rolling bearing fault induced vibration is often expressed as an amplitude modulated signal.The signal should be considered to be cyclostationary,because its second order statistics appear to posses definite period.In this work,the characteristics of the statistics,i.e the cyclic autocorrelation function and the cyclic spectrum density function,are analyzed using cyclic statistics.Based on a mathematical model of an amplitude modulated signal,a method of demodulating the cyclic autocorrelation function and exeracting the amplitude modulating signal in the cyclic frequency domain is proposed.The method is verified by a simulated signal and applied to the fault diagnosis of a rolling bearing,from which the fault feature frequencies of its inner ring,outer ring and rolling elements are successfully extracted.