柴油机曲轴轴承磨损的阶比—小波时频特征提取

COT-Wavelet Time Frequency Feature Extraction of Crankshaft Bearing Wear for Diesel Engine

由于发动机加速过程振动信号故障特征信息表现得更为明显,据此提出计算阶比跟踪和小波时频相结合的方法。将振动信号按等角度间隔进行软件重采样,得到角域内的平稳信号,再进行基于小波系数相关性的小波时频分析。信号经过这种处理后可以同时反映信号阶比域和角度域的特征,即得到阶比—角度能量分布,通过比较不同阶比带内的能量分布来反映不同工况的变化。诊断实例表明,该方法能有效提取柴油机曲轴轴承的故障特征。

Based on the fault feature information of vibration signal during the acceleration of diesel engine, the method of combining computed order tracking （COT） and wavelet time frequency analysis was proposed. Resampling the vibration signal with the equivalent angle interval, the steady signal of angle domain was acquired, and then the wavelet time frequency analysis of signal was carried out based on the wavelet coefficient correlation. Accordingly, the order-angle energy distribution reflecting order-domain and angle-domain feature was acquired. Compared with the energy distribution of different order bands, different working conditions of engine could be reflected; The diagnosis cases indicate that the method can extract the feature of crank- shaft bearing fault effectively.