Unbalance Identification of Nonlinear Rotor Bearing System Based on Perturbation Method Solutions

In order to identify the unbalance and phase of the rotor,the three order expressions of oil film force model are built,and the genetic algorithm is introduced to identify the dynamic coefficients of the oil film force and the unbalance,so the identification problem is transferred into an optimization problem.The dynamic function is solved by perturbation method,so the three order approximate solution of the system can be obtained.The amplitude and phase of the work frequency,double frequency and three multiple frequencies can be extracted from the measure signal and the perturbation solutions by correlation analysis method.The vector differences of the vibration component between the perturbation solution and the measure signal are as the appropriate function and the weighted error of the components are minimum to evaluate the optimization results.The numerical results show that the method can agree well with the parameter identification precision.It is validity and the optimization time is short.