衔铁平行运动的磁微执行器Pull-in机理分析

Analysis for the Pull-in Mechanism of Slab Magnetic Microactuators

与静电微执行器类似,磁微执行器中也存在重要的Pull-in失稳问题。但相对于静电微执行器详尽的模型相比,研究磁微执行器的文献很少。对于宏观器件,由于磁芯磁阻可以忽略,所以可利用电磁类比,得到Pull-in失稳参数。而对于微观器件,磁芯磁阻不可以忽略,不可利用电磁类比。基于小信号模型对衔铁平行运动的磁微执行器Pull-in的失稳现象首先进行了分析和建模,考虑了微磁芯磁阻,在建立磁微执行器动态小信号模型的基础上,分析发现衔铁平行运动的磁微执行器中不存在Pull-in现象。然后又采用能量法研究了同样的Pull-in失稳问题,得出了和力法相同的结论。最后,给出了一个分析实例,以反映微磁芯磁阻对Pull-in的影响,同时证实了衔铁平行运动的磁微执行器中不存在Pull-in现象的结论。结论对于磁微执行器的设计具有重要意义。

The unstability of magnetic microactuators, which is referred to as the magnetic Pull-in phenomenon similar to electrostatic actuators, is of important. A generalized force approach is firstly used to model the unstability of slab magnetic microactuators. The reluctance of the magnetic core is considered. The critical value of applied current beyond which the dynamic response of small gain model becomes unstable is investigated and find that there is no Pull-in point in this configuration. Then a generalized energy approach is used to model the same problem. The results of two approaches are identical. Finally, a case study of the slab magnetic microactuator is presented.