考虑动圈偏心的电动振动台等效电磁力计算方法

A Calculation Method of Equivalent Electromagnetic Force for Electrodynamic Shakers Considering Moving Coil’s Eccentricity

为了反映动圈激励电磁力对偏载工况下电动振动台横向振动的影响,提出了一种考虑动圈偏心影响的电动振动台等效电磁力计算方法。综合选取动圈通电电流、垂向位置、翻转偏心角度、径向平移偏心距及方向等5个因素,通过求取径向平移偏心距极限及假设虚拟偏心距进行变量代换,解决了现有正交试验设计方法难以应用于多个因素之间存在取值相互约束情况的问题。通过电磁有限元仿真获得了与动圈分布电磁力等效的集中电磁力样本,采用神经网络方法进行样本拟合获得了动圈全运动工况等效电磁力。仿真结果表明:径向等效电磁力主要随翻转偏心角度的增加而增加,且在大电流工况增加更迅速;采用所提方法获得的等效电磁力相对误差均在10%以内,可在满足工程误差要求的同时快速实时获得动圈全运动工况等效电磁力,解决了由有限元及精确解析方法计算等效电磁力速度慢所导致的无法进行电动振动台电磁-结构双向耦合仿真的问题。该方法也可应用于其他相似的运动系统受力计算问题。

A calculation method of equivalent electromagnetic force considering moving coil’s eccentricity is proposed to reflect the influences of the moving coil’s electromagnetic forces on the lateral vibration of the electrodynamic shaker under offset loading conditions.Five factors including the moving coil’s current,vertical position,flipping eccentricity angle,radial translating eccentricity distance and direction are considered.The problem that it is difficult to apply the existing orthogonal test design method to the situation with a mutual constraint among multiple factors’values is solved by calculating the radial eccentricity distance limit and assuming a virtual eccentricity distance.The concentrated electromagnetic force samples equivalent to the distributed electromagnetic forces of the moving coil are obtained through an electromagnetic finite element simulation.A neural network method is used to fit the samples and the equivalent electromagnetic forces in full moving conditions are obtained.Simulation results show that the radial equivalent electromagnetic force mainly increases with the increase of flipping eccentricity angle,especially increases rapidly at the high current condition.The relative errors of the equivalent electromagnetic forces obtained by the proposed method are within 10%.The equivalent electromagnetic forces in full moving conditions can be effectively obtained in real time while meeting the engineering requirement of calculation error.The problem that the electrodynamic shaker’s electromagnetic-structure bidirectional coupling simulation can not be carried out due to the slow speed of the finite element method and the exact analytical method to calculate the equivalent electromagnetic force is well solved.The proposed method can also be applied to the calculation of forces on other similar moving systems.