微动隔振平台参数摄动对模态参数的影响

Influence of Parameter Perturbation of Micro-Vibration Isolation Platform on Modal Parameters

分析隔振平台的模态参数辨识方法。用参数摄动重分析方法,仿真分析微动隔振平台理论模型中参数的摄动引起的模态参数的改变,以及在模态实验中对模态参数辨识精度的影响。结果表明:同向支撑刚度不等使得部分原本不耦合的模态之间产生了弱耦合作用,并使系统模态频率和振型均有不同程度的变化;垂向重心位置摄动对平台模态频率的影响较大;支撑刚度及垂向重心位置偏差对模态频率的辨识影响较小,而对模态振型的辨识精度有较明显影响。

The modal parameter identification method for a 6-DOF （degree of freedom） micro-vibration isolation platform is analyzed. Based on parameter perturbation re-analysis method, variation of the modal parameters in the theoretical model of the micro-vibration isolation platform induced by the parameter perturbation is simulated. Its influence on the accuracy of modal parameter identification in modal experiment is analyzed. The results show that weak coupling is generated among some originally uncoupled modals due to the unequal stiffness of the identically directed supports. It also causes the variation of modal frequency and vibration mode of the system. It is found that perturbation of the vertical location of the gravity center has large influence on modal frequency of the platform. The stiffness of the supports and the location error of the gravity center have small influence on modal frequency identification, but they have large influence on identification accuracy of the vibration mode.