基于复包络谱的滚动轴承故障特征提取方法研究

Fault feature extraction of rolling bearings based on complex envelope spectrum

提出一种基于复包络谱的滚动轴承故障特征提取方法。采用正交采样技术获取滚动轴承同一支撑处互相垂直方向上的振动信号,并将其组成一个复数信号;运用二元经验模态分解(bivariate empirical mode decomposition,BEMD)将复数信号分解成若干复固有模态函数(complex intrinsic mode function,CIMF)之和,应用Hilbert变换解调出CIMFs的实部和虚部包络信号,将实部和虚部的包络信号组成复数形式的包络信号,并用复傅里叶变换求其频谱。依据复数形式的包络信号的傅里叶谱提取滚动轴承的复合故障特征频率,并与全矢谱做了对比分析。复合故障试验案例证明了该方法的可有性和有效性;XJTU-SY滚动轴承数据集的复合故障分析进一步验证了该方法提取的故障特征更为全面。

A fault feature extraction method of rolling bearings based on complex envelope spectrum was proposed.Firstly,the vibration signals at the same support of rolling bearings were obtained by orthogonal sampling technology,and they were composed into a complex signal.Secondly,the complex signal was decomposed into the sum of several complex intrinsic mode functions(CIMF)by using the bivariate empirical mode decomposition(BEMD).The envelope signals of real part and virtual part of CIMFs were demodulated by the Hilbert transform.The envelope signals of real part and virtual part were composed of complex envelope signals,and the spectrum was calculated by the complex Fourier transform.According to the characteristics of the complex signal Fourier transform,which can enhance the characteristic amplitude and synthesize the characteristic frequency,the fault characteristic frequency of rolling bearing was extracted according to the complex envelope signal Fourier spectrum.According to the Fourier spectrum of the complex envelope signal,the fault characteristic frequency of rolling bearing was extracted and compared with the full vector spectrum.A composite fault test case proved the feasibility and effectiveness of this method;the composite fault analysis of XJTU-SY rolling bearing data set further proved that the fault features extracted by this method are more comprehensive.