多小波自适应构造方法及滚动轴承复合故障诊断研究

Adaptive construction of multiwavelet and research oncomposite fault diagnosis of rolling bearing

机械设备的复合故障由于其故障的多样性、强弱的不平衡、故障间的相互影响等特性,给全面准确地诊断造成困难。多小波具有多个时频特征有所差异的基函数,可以匹配多个故障特征,对于复合故障的诊断具有先天优势。提出了多小波的自适应对称提升方法,以峭度为优化目标对多小波进行自适应构造,对信号进行冗余分解,获得特征频率的相对能量分布,依据相对能量比选择敏感频带,实现对复合故障的一次性识别与诊断。以电力机车滚动轴承外圈与内圈、外圈与滚动体的复合故障诊断为例,验证了该方法的有效性。

The diagnosis of composite fault occurred in mechanism is a difficult challenge at present. It is hard to diagnose the composite fault exactly and comprehensively due to the diversity and influence of faults. Multiwavelet has two or more base functions and many excellent properties. It might match two or more features of composite fault. The theory of multiwavelet supplies a reference for the solution of composite fault. The paper proposes an adaptive construction of multiwavelet using symmetric lifting. The kurtosis is selected to be the object of optimization. A new multiwavelet is constructed for the signal and used to decompose it redundantly. The distribution of relative energy for the characteristic frequency is computed. The composite fault is diagnosed by the sensitive frequency bands selected. Taking the composite faults of rolling bearing as exampies, the effectiveness of the proposed method is proved.