变转速齿轮箱复合故障的自适应时变滤波分析

Adaptive time-varying filtering method for gearbox compound fault diagnosis under variable rotational speed

复合故障诊断是机械故障诊断领域的一大难点。齿轮箱出现复合故障时,受传递路径、测点布置等影响,所拾取的复合故障振动信号中,各故障成分会呈现强弱不平衡,特别在变转速条件下,故障特征具有时变特性。因此,针对变转速下的齿轮箱复合故障诊断,提出了一种基于频域滤波的自适应时变滤波方法。该方法在频域构建自适应时变滤波器,采用自适应时变滤波器将包含齿轮故障特征的时变滤波信号从齿轮箱复合故障信号中分离出来,并进行包络阶次谱分析,以提取齿轮故障特征;同时,对残余信号(齿轮箱复合故障信号与时变滤波信号的差值)进行包络阶次谱分析,以提取轴承故障特征。算法仿真和应用实例表明,自适应时变滤波方法可有效分离变转速下齿轮和滚动轴承的故障特征。

Compound fault diagnosis is a hard problem in mechanical fault diagnosis.When compound fault occurs in a gearbox,strength imbalances between fault signal components in the measured compound fault vibration signal will appear usually,which is affected by the transfer path,measuring point arrangement and so on.Especially when the gearbox runs with variable rotational speed,the fault feature is of time-varying characteristics.Therefore,aiming at compound fault diagnosis for gearboxes operating with variable rotational speed,a frequency-domain adaptive time-varying filtering method was proposed.In the proposed method,an adaptive time-varying filter was designed in frequency-domain,and the time-varying filtered signal carrying gear fault characteristics was extracted from the compound fault signal of gearbox by using the adaptive time-varying filter,which in turn by the envelope order spectrum analysis,the fault features of the gears were extracted.Meanwhile,by the envelope order spectrum analysin on the residual signal,which is the difference between the gearbox compound fault signal and time-varying filtered signal,the fault features of the bearings were extracted.Simulations and application examples indicate that the proposed adaptive time-varying filtering method can effectively separate the fault features of the of gears and rolling bearings running with variable rotational speed.