Research On Structure Design Of Silicon Micromachined Gyroscope With Shock Resistance

Silicon micro-machined gyroscope is a micro-sensor used to measure angular rate,compared with traditional gyroscope,which has not only a smaller size,light weight but also other advantages like good dynamic performance,high reliability and easy to digitization.It is widely used in civilian and military fields.This paper designed a silicon micro-machined gyroscope with high shock resistance based on theoretical analysis and finite element analysis software ANSYS.The main contents of this paper are as follows:(1)Introducing the development of the silicon micro-machined gyroscopes and the research status of shock resistance of the silicon micro-machined gyroscopes.Then describing the basic working principles and Kinetic equations of silicon micro-machined gyroscope,and analyzing its driving and sensing methods.(2)Designing a structure of silicon micro-machined gyroscope with high shock resistance.Choosing the appropriate form of structure,establishing the shock response model,studying the relationship between the shock response and the characteristic parameters of structure and the shock loads in detail.According to the relationship,choosing suitable methods of driving and detecting,designing supporting beams,lever coupling mechanism in driving direction,coupling mechanism in sensing direction to finish the design of overall structure.Designing elastic stoppers to further improve the shock resistance of the micro-mechanical gyroscope.With software ANSYS,the modal simulation of the gyroscope is carried out to determine the structure parameters to obtain the appropriate modal frequency,and theoretical calculations are carried out according to the parameters.(3)Doing simulation analysis for the designed structure using software ANSYS.Analyzing from transient simulation,gravity simulation,harmonic response simulation and the packaging thermal stress simulation and other aspects to verify the feasibility of the structure design.Among them,transient simulation includes the simulation of the shock resistance of the structure with and without stopper mechanism,and the processing error's influence on the shock response,harmonic response simulation includes the analysis in driving direction and sensing direction,the packaging thermal stress simulation includes the thermal stress simulation of the structure during the encapsulation at 400? and the residual themal stress of the structure when the temperature changes from 400? to 20?.(4)Processing the silicon micro-machined gyroscope by DDSOG technique and testing the designed silicon micro-gyroscope,the open loop test results show that the driving frequency is 12630Hz,the detection frequency is 12772Hz,the in-phase natural frequency in the driving direction is 12920Hz,the in-phase natural frequency in the sensing direction is 13019Hz.The results are almost the same as designed values,the natural frequency of the in-phase vibration mode of the structure is 290Hz higher than that of the inverse vibration mode frequency in the driving direction,conforming to the design of the lever coupling mechanism in the driving direction,also,the natural frequency of the in-phase vibration mode of the structure is 247Hz higher than that of the inverse vibration mode frequency in the sensing direction,conforming to the design of the coupling mechanism in the sensing direction.Finally,finishing the ceramic encapsulation of the silicon micro gyroscope and the packaging process is described in detail.