基于全息谱分析的非线性转子系统不平衡量识别

Unbalance Identification of Nonlinear Rotor System Based on Holospectrum Analysis

在实际现场动平衡中,没有必要完全识别出系统的参数,而只要将不平衡量识别出来就行了,为此提出在不识别轴承参数基础上对非线性转子系统不平衡量识别的一种新方法。在不平衡量识别中,将所有与轴承参数有关的力都归结到油膜力中,轴承油膜力接近周期力,这样可将其傅里叶展开;然后根据不平衡响应特点得到包含不平衡激励和油膜力工频分量的方程组,利用油膜力和不平衡量的工频的周期力作用位置不同将两者分离开;再引入全息谱技术,利用相关分析的方法,提取振动测量所得信号中的工频信号,把工频响应从振动信号中分离出来,代入方程组求解方程,求得不平衡量。通过大量的数值计算,分析比较不平衡前后的工频振动,研究该方法的识别精度、可靠性以及各种影响因素;最后从试验方面验证了识别方法的正确性。

In field balance,if only the unbalance can be identified there＇s no need to identify the bearing coefficient,so a new method,based on without the bearing parameter identification,is proposed to identify unbalance of nonlinear rotor system. In the new method,those forces related to the bearing parameters are all ascribed to the oil film force. The oil film force is nonlinear,but it is closed to periodic force. So it can be expanded by Fourier transform. According to the characteristic of unbalance response the identification equations of power-frequency vibration can be acquired. In this algorithm the power-frequency vibration is caused by unbalance and oil film force,but it can be separated by different location matrix of the two kinds of forces. Based on holospectrum and correlation,the power-frequency signal can be extracted from measured vibration. Then,the unbalance can be identified by solving the equations. In order to test this new algorithm the power-frequency vibration amplitudes before and after balancing are compared through a lot of numerical simulations. The simulations show that the new algorithm is effective,stable and robust. Finally,the method is validated by experiment.