适用于参数识别的一种非线性油膜力表达式

基于求解非线性方程的摄动法思想，将油膜力沿轴心轨迹展开成小参数的三阶多次项的形式，用最小二乘回归方法求得动态系数。通过仿真比较非线性非稳态油膜力、线性油膜力、三阶多项式油膜力三种模型下的不平衡响应，由计算结果知三阶多项式油膜力模型与非线性非稳态油膜力模型吻合较好。这种非线性油膜力的三次多项式模型可用于非线性转子轴承系统的参数识别和不平衡量识别。

EXPRESSION OF NONLINEAR OIL FILM FORCE SUITING FOR PARAMETER IDENTIFICATION

On the basis of the idea of small parameter, the expression of nonlinear oil film force suiting for parameter identification is put forwarded, in which the dynamic coefficients may be evaluated based on the transient journal orbit using a three order polynomial expansion of bearing reaction. The dynamic response of the rotor bearing system is numerically investigated under different model of oil film force conditions. The results show: The nonlinear response by adopting three order polynomial oil film force model is more accurately predicted than by adopting the linear model. So the identification precision is satisfactory and this technique can be effectively applied in field balancing processes or rotor unbalance fault diagnosis.