动平衡测试系统中不平衡量的测试方法研究

Research on testing method of unbalance in dynamic balance testing system

针对动平衡测试系统中不平衡量测试精度较低的问题,提出了一种基于希尔伯特-黄变换(HHT)的滤波方法,该方法应用于动平衡测试系统,对获取的转子原始振动信号和转频信号进行分析,可以有效得到不平衡量的质量和相位。方法先对原始振动信号进行经验模态分解(EMD),将振动信号分解为一系列固有模态函数(IMF),再经过希尔伯特(Hilbert)变换计算出各IMF的希尔伯特边际谱,根据转子转频信号滤除掉高低频干扰信号,筛选出针对不平衡量的有效振动信号,根据该信号的幅度和频率即可得到不平衡量的质量和相位。与普通数字滤波方法比较,实验结果表明,该方法用于动平衡测试系统比普通数字滤波方法精度高,效果好。

A new Hilbert-Huang transform （HHT）-based filtering method is proposed to solve the problem of low accuracy of unbalance measurement in dynamic balancing test system. This method is applied to the dynamic balance test system to analyze the original vibration signal and the frequency signal in order to infer the quality and phase of the unbalance. Firstly, the vibration signal can be resolved into a series of intrinsic mode functions （IMFs） through empirical mode decomposition （EMD）. Secondly, the Hilbert marginal spectrum of these IMFs will be figured out by Hilbert transform. Finally, combining with the trochanter＇ s frequency , the useful vibration signal are able to be selected from the original signal. According to the amplitude and frequency of the useful vibration signal, the quality and phase of the unbalance are capable of figured out. The experimental results show that the proposed method is more accurate and more effective than the conventional digital filtering method in the dynamic balance measurement system.