A MEMS Universal Inertial Switch Design That Recognizes The Load Orientation

In this paper,a MEMS omnidirectional inertial switch with the ability to identify the azimuth of impact load was developed.With the advantages of small volume,strong anti-overload ability,short response time,long contact duration,and good ability to detect direction of impact load,the switch meets the need of the trigger fuze,so this paper will have important practical significance to fuze miniaturization and intelligence.Through the analysis of research status of the existing MEMS inertial switch,the view is put forward that a MEMS omnidirectional inertial switch with the ability to identify the azimuth of impact load can be used in the fuze of directional fragment warhead.Then the theoretical model of the switch is established,and the influence of the structure parameters on the performance of the switching threshold and response time is analyzed;It is proposed that the switch can detect the orientation of the load by different electrode contact states and according to this,the switch structure is designed.The performance of the switch is simulated and analyzed by using the finite element software.The simulation results show that the switching threshold is 400g-566g in XOY plane,649g in Z axial direction,and the switch can distinguish azimuth of impact load in range of the hemispherical space.Under the acceleration of 800g-0.6ms,the minimum closing time is 55?s and the maximum response time is 342?s.Under the acceleration of 20000g-0.6ms,the maximum structural stress is 770.03MPaThe switch structure is fabricated by UV-LIGA technology,and is packaged by PLCC-28.The size of the MEMS switch is 4.8mm*4.8mm*0.265mm,and the size of the package is 11mm*11mm*2.05mm.To analyse the performance of the switch,related experiment are conducted and the experimental results are in good agreement with the simulation results.