一种非平稳转速下不平衡信号提取方法

Extraction Method for Unbalanced Signal in Non-stationary Speed

针对动平衡测量中实际存在的转速波动问题,提出一种基于经验模态分解(empirical mode decomposition,简称EMD)和瞬时频率估计的不平衡信号提取方法。与传统的平稳信号分析方法不同,该方法采用3次样条插值法从键相信号中获取转子的瞬时频率,由瞬时频率构造不平衡信号,进而采用最小二乘法(least square method,简称LSM)辨识出不平衡信号的幅值和相位。为提高幅值和相位估计的精度,采用EMD算法对振动信号进行滤波处理后,再从中抽取数据样本。仿真和实验结果表明,该方法能够有效克服转速波动和干扰信号对不平衡信号提取精度的不利影响,提高不平衡量测量精度和稳定性,非常适合于工程应用。

An extraction method for na unbalanced signal based on EMD and instantaneous frequency estimation is presented in order to minimize the disadvantages of speed fluctuation in dynamic balancing measurement.In contrast to a traditional stationary signal analysis method,the proposed method obtained instantaneous frequency from the key phase signal by cubic spline interpolation,and built an unbalanced signal whose amplitude and phase were identified by a least square algorithm.In order to improve the accuracy of parameter identification,na EMD algorithm was used to filter vibration data before extracting sample data for least square estimation.Simulation and experimental results showed that this method can overcome the adverse effects of speed fluctuation and increase the accuracy and stability of unbalanced signal measurement,which is suitable for applications in engineering.