Terfenol-D磁致伸缩微小驱动器磁路设计

Magnetic Circuit Design for Terfenol-D Driven Magnetostrictive Mini-actuator

提高磁致伸缩驱动器驱动效率的关键环节是建立优化的驱动器磁路。本文基于准静态条件下线性磁致伸缩理论,得出磁致应变S与磁致伸缩材料内部磁场强度B的关系;并根据对无永磁磁偏磁路的分析进一步得出磁致应变S与磁路磁阻R和漏磁磁阻R1的对应关系。应用有限元方法对3种典型磁路结构的磁化效果进行对比分析,验证磁路结构的变化——即磁阻R和漏磁磁阻R1的相应改变对磁致伸缩材料磁化程度的不同影响,进而得出微小驱动器磁路壳体适宜壁厚为2mm,导磁材料的磁导率为2000μ0。根据此结果和磁路设计的2个遵循原则,对一7mm×20mmTerfenolD棒驱动的驱动器进行了磁路设计,应用ANSYS验证了该结构设计的合理性,并试制了驱动器样机。

To establish an optimum magnetic circuit is the key for improving the driving efficiency of a magnetostrictive actuator. Based on the empirical quasi-static linear equation, in this paper, a relationship between the magnetic flux density B inside the magnetostrictive rod and the reluctance R, the leakage reluctance R_~1 of the whole magnetic circuit are deduced. According to the relationship and the magnetic circuit design principles, three typical structures of magnetostrictive magnetic circuit have been analyzed by ANSYS in order to verify the influence on B by R and R_~1 , which assists to understand how to establish an optimum magnetic circuit of centi-metric magnetostrictive actuator. As a result, a 7 mm×20 mm Terfenol-D rod driven mini-actuator was designed, then fabricated after identifying its structure having the magnetic circuit with well-done magnetization inside the driving rod. The mini-actuator prototypeis finally made, which is illustrated in the paper, too.