零刚度磁悬浮重力补偿器的分析与改进

Analysis and Improvement of Zero Stiffness Magnetic Levitation Gravity Compensator

零刚度磁悬浮重力补偿器(ZMLGC)工作在零刚度点附近,用以平衡重力并实现超低频隔振。但是,随着ZMLGC的运动其轴向刚度增加显著,制约了隔振性能。为有效减小工作行程内轴向刚度的变化,首先基于等效电流模型分析了零刚度生成原理。然后,利用椭圆积分建立了ZMLGC的磁场和电磁力解析模型,并在Matlab中编程实现。提出了不等厚的动子拓扑结构以改善气隙磁场分布,结合解析模型和有限元模型进行了结构参数设计计算。最后,搭建样机进行了静态和动态实验。结果表明,在±1 mm工作行程内,ZMLGC的最大刚度降低了四倍,达到10 N/m。

The zero stiffness magnetic levitation gravity compensator(ZMLGC)works near the zero stiffness point to isolate extreme low-frequency vibration,but the stiffness increases significantly with the movement of ZMLGC.To improve the stiffness characteristics,based on the equivalent current model,this paper first analyzed the zero stiffness generating law of ZMLGC.Then,the analytical magnetic field and force model of ZMLGC was established by elliptic integral,and realized by Matlab.The unequal thickness mover topology was proposed to improve the airgap magnetic field distribution,and the structural parameters were calculated by combining analytical model and FEM.Lastly,a prototype was constructed and the static and dynamic experiments were carried out.The results show that the maximum stiffness within±1 mm working stroke decreases by four times and reaches 10 N/m.