基于高阶累积量的轴承并发故障振动信号分析

Analysis of Vibration Signals of Bearing Concurrent Fault Based on Higher Order Cumulants

针对并发故障特征相互耦合、互相调制且容易被噪声淹没而难于提取的实际问题,利用高阶累积量能有效抑制噪声、识别相位耦合和检测系统非线性的特性,提出了基于高阶累积量的AR双谱方法,并对曲轴轴承、连杆轴承并发故障加速振动信号进行分析.结果表明,基于高阶累积量的AR双谱能从多种激励源相互耦合、互相调制的复杂信息中,分辨出各运行部件的激励频率.曲轴轴承和连杆轴承并发故障时,信号之间存在耦合与调制现象,基于高阶累积量的AR双谱能对曲轴轴承、连杆轴承产生的激励信号进行有效地去耦和解调,分辨出并发故障时,曲轴轴承特征频段为1.5～1.8,kHz,连杆轴承特征频段为0.9～1.1,kHz,特征频段的幅值能量可以作为诊断并发故障的特征参数,表明AR双谱是提取曲轴轴承、连杆轴承并发故障的一种有效方法.

Extraction of concurrent fault feature is difficult due to feature coupling and modulating,the trait of higher order cumulants（HOC）is able to restrain the noise and identify phase coupling and detect nonlinear of system.The AR-bispectrum based on HOC is proposed and used to analyze the accelerating vibration signal of concurrent fault of crank bearing and coupler bearing.Analysis result shows that AR-bispectrum based on HOC can distinguish the excited frequency of each running part from the complicated signal from the multi-excited sources.When the concurrent fault of crank bearing and coupler bearing oc-curs,the coupling and modulation in signal will appear.The AR-bispectrum based on HOC is able to de-couple and demodulate the signal,and identify the feature frequency of crank bearing which is between 1.5,kHz and 1.8,kHz,and the feature frequency of coupler bearing is between 0.9,kHz and 1.1,kHz.Am-plitude of feature frequency can be used as the feature parameter in concurrent fault diagnosis.AR-bispectrum based on HOC is an effective method to extract the concurrent fault feature of crank bearing and coupler bearing.