分形与谐波小波相结合的车辆振动信号分析

Vibration Signal Analysis of Vehicle by Combination of Fractal and Harmonic Wavelet Technique

介绍了机械振动信号分析中应用的分形方法 ,并对模拟信号进行了分形分析。结合谐波小波分析技术 ,对实际车辆的复杂振动信号进行了分形研究 ,得出可以把多重分形的较高维数作为判断信号复杂程度和是否存在故障的依据的结论。研究了车辆复杂振动信号的混沌特征 ,发现具有梳状谐波共振谱峰的信号难以进行分形分析 。

The basic concept of fractal was introduced. The main fractal methods applied in signal analysis of mechanical vibration were presented. The analog signal of beeline, sine function and white noise were analyzed by the fractal method. The complex vibration signal of vehicle was decomposed by harmonic wavelet, the frequency part, which is a matter of interest, was picked up and then the fractal analysis was performed. The conclusion was obtained according to the results from the fractal analysis, in which the complicated degree and the fault of vehicle vibration signal could be estimated by higher dimension of multi fractal. The chaos characteristic of complicated vibration signal of vehicle was researched according as the collected typical signal. It is found that the vehicle signal with pectination resonance spectrum can not be analysed by fractal method and has an obvious characteristic of chaos.