具有阈值可调功能的磁自锁MEMS惯性开关

Design and analysis of micro inertial switch with magnetic latch and adjustable threshold

摘要:

设计了一种阈值为5g的低g值磁自锁微机电系统(MEMS)惯性开关，具有阈值可调和自回复功能。该惯性开关的惯性敏感单元由1个方形质量块、1块固定在质量块下的方形棋盘状磁铁和4根支撑它的方形阿基米德螺旋梁组成。磁铁和4块位于移动电极下方的铁磁性固定电极、双层平面线圈一起共同实现磁自锁和阈值调节功能。通过有限元仿真软件ANSYS对其进行仿真分析，利用激光加工和PCB工艺制造样片机，并通过离心机对样品进行性能测试。测试结果显示，制作的MEMS惯性开关在垂直敏感方向上的阈值加速度为5.27g，通过施加-0.5~0.5 A范围的电流，阈值的调整范围为6g~3.75g。结果表明此结构能够在实现闭锁功能的同时，在无外力作用的情况下实现自回复，且在一定范围内阈值可调。

Abstract:

A low-g-value magnetic self-locking Micro-Electro-Mechanical Systems(MEMS) inertial switch with a threshold of 5g, featuring adjustable threshold and self-recovery capabilities, has been designed. The inertia sensitive unit of this inertial switch consists of a square mass block, a square chessboard-shaped magnet fixed beneath the mass block, and four square Archimedean spiral beams supporting it. The magnet, along with four ferromagnetic fixed electrodes located beneath the moving electrodes and a double-layer planar coil, jointly achieve the functions of magnetic self-locking and threshold adjustment. Simulation analysis is conducted using the finite element simulation software ANSYS. The prototype is manufactured by using laser processing and PCB technology, and the performance of the sample is tested by using a centrifuge. The test results show that the fabricated MEMS inertial switch has a threshold acceleration of 5.27g in the vertical sensitive direction. By applying a current in the range of -0.5 to 0.5 A, the threshold adjustment range is from 6g to 3.75g. The results indicate that this structure can achieve the locking function while enabling self-recovery without external force and allowing threshold adjustment within a certain range.