基于阶比跟踪与VMD的瞬变工况发动机故障特征提取

针对发动机加速过程振动信号的非平稳性和存在强背景噪声的特点,提出阶比跟踪与变分模态分解(VMD)相结合的方法。对于柴油机曲轴轴承故障和汽油机连杆轴承模拟试验振动信号,利用阶比跟踪技术将时域上的非平稳信号转化为角域上的伪平稳信号,利用VMD对重采样信号进行分解,选择包含故障信息的模态分量,计算其阶比、转速、功率谱所构成的三维阶比谱阵,提取故障特征。仿真分析和故障模拟试验验证了该方法的有效性。

Extraction of Features of Diesel Engine Faults Under Transient Operations Based on Order Tracking and Variational Mode Decomposition

A method based on the order tracking and variational mode decomposition(VMD) was proposed to solve the problem of non-smoothness of and big background noise in engine vibration signal. For the vibration signals of diesel engine crankshaft bearing fault and gasoline engine connecting rod bearing fault, a non-smooth signal in the time domain was converted into a pseudo smooth signal in the angular domain based on the order tracking. Then the converted signal was decomposed into several components with VMD, and the components that contain fault information were selected. The three dimensional spectral array of order, speed and power spectrum of the selected components was calculated, and the fault feature was extracted. The effectiveness of the proposed method was verified by simulation and experiment.