阀用超磁致伸缩致动器弓张结构静、动态建模与优化

Static and Dynamic Property Optimization Design on Bow-type Structure of Giant Magnetostrictive Actuator for Valve

为满足大流量超磁致伸缩电液伺服阀的驱动需要,设计了一种结构紧凑的弓张放大式超磁致伸缩致动器;基于力学基本原理和振动理论知识建立了弓张结构的静、动态模型;分析了弓张结构尺寸参数对其静、动态性能的影响;结合弓张放大式超磁致伸缩致动器应用于电液伺服阀的要求,利用多目标优化法确定了其结构尺寸最佳参数值,并利用有限元法对其静、动态模型进行了验证;设计了弓张放大式超磁致伸缩致动器样机,搭建了实验系统,并进行了静、动态实验。实验结果表明,弓张结构的放大倍数在8.13~8.72间波动,输出端最大位移可达107.9μm,固有频率约为168 Hz,测试所得结果与其静、动态模型计算值基本吻合;通过与优化前的性能相比,弓张结构的静态放大倍数在满足要求的条件下,其动态固有频率提高了55.6%;所设计的弓张放大式超磁致伸缩致动器基本上能够满足伺服阀的驱动要求,证明了该优化设计方法的有效性。

A compact giant magnetostrictive actuator with bow-type amplifier structure was designed to meet the driving needs of large-flow electro-hydraulic servo valve. Based on mechanics and vibration theory,the static and dynamic models of this structure were established. The influence of the dimensional parameters towards its static and dynamic performance was analyzed,and it was concluded that its static and dynamic properties were mutually restrictive. Combining with the application requirements of giant magnetostrictive actuator in electro-hydraulic servo valve,the multi-objective optimization design was conducted for the bow-type structure,and then the static and dynamic models were validated by the finite element analysis. Finally, the giant magnetostrictive actuator with bow-type displacement amplifier structure was prototyped to test its static and dynamic properties. The results showed that the amplification ratio of this structure was fluctuated from 8. 13 to 8. 72,the maximum output displacement was 107. 9 μm,and the natural frequency reached 168 Hz. The results were basically in consistent with the theoretical models. Compared with the performance before optimization,the natural frequency was increased by 55. 6% when the requirement of the static magnification was met. The actuator designed can basically meet the driving requirements of servo valve,which proved that the optimized design method was effective.