无转速计下变工况滚动轴承故障特征量化表征提取

Tacholess quantitative characterization of rolling bearing fault feature under varying conditions

无转速计下变工况滚动轴承振动信号中各信号分量来源难以确定以及瞬时转频准确估计困难,而现有大多数研究依赖于已知转速并关注于时变冲击带来的频谱畸变,鲜有在无转速计变工况下开展轴承故障特征提取探究。提出无转速计下变工况滚动轴承故障特征量化表征提取方法,从振动信号希尔伯特包络中提取轴承故障特征,为定量描述各振动包络分量间关系,提出基于来源假设的特征模型与量化表征方法,利用同步压缩小波变换的时频重排与可重构特性,基于最大能量与最小曲率准则依次估计多时频脊瞬时频率,为降低广义解调后振动包络中干扰分量对量化结果的影响,提出基于选择性重构与广义解调的变工况下干扰抑制与平稳化重置方法。将所提方法用于仿真信号以及轴承振动数据分析,10 k长度信号包络分量在不同来源假设下的特征提取用时约为3 s,同时在无转速计下实现了对2 s内转速变化分别约为300 r/min和200 r/min的内圈故障轴承以及复合故障轴承的特征提取。

The component of rolling bearing vibration is difficult to be determined and the instantaneous rotational frequency is hard to be estimated accurately under varying conditions without a tachometer.Most studies mainly rely on the prior speed knowledge and focus on the spectrum distortion caused by time-varying impacts,while little attention has been paid to tacholess bearing fault feature extraction under varying conditions.A novel tacholess quantitative characterization method is proposed for rolling bearing fault feature extraction under varying conditions.The vibration Hilbert envelope is utilized to extract the bearing fault feature.To quantitatively describe the relationship among vibration envelope components,a model based on source hypothesis for feature extraction as well as a quantitative characterization method is proposed.The instantaneous frequencies of spectrogram ridges are estimated consecutively based on the maximum energy-minimum curvature criterion by resorting to the time-frequency reassignment and reconstruction capability of the synchrosqueezed wavelet transform.To reduce the influence of various interference in the generalized demodulated vibration envelope on the quantitative results,a method of interference suppression and stationarization reset under varying conditions is proposed based on the selective reconstruction and the generalized demodulation.The proposed method is applied to analyze the simulated signal and bearing vibration data.It takes about 3 s to extract the features of envelope component with length of 10 k points under different source hypotheses.Meanwhile,the fault characteristics of inner race fault bearing with a speed change of about 300 r/min in 2 s and that of the compound fault bearing with a speed change of about 200 r/min in 2 s are quantitatively characterized without a tachometer.