基于质量-刚度解耦的微半球谐振陀螺频差高精度修调方法  

High-precise trimming method for micro hemispherical resonator gyroscopes based on mass-stiffness decoupling

作　　者：李斌[1] 席翔 卢坤 段京保 孙江坤 石岩 张勇猛 肖定邦[1] 吴学忠[1] LI Bin;XI Xiang;LU Kun;DUAN JingBao;SUN JiangKun;SHI Yan;ZHANG YongMeng;XIAO DingBang;WU XueZhong(College of Intelligence Science and Engineering,National University of Defense Technology,Changsha 410073,China)

机构地区：[1]国防科技大学智能科学学院,长沙410073

出　　处：《中国科学：技术科学》2023年第8期1400-1410,共11页Scientia Sinica(Technologica)

基　　金：国家自然科学基金(批准号:5220053420,520755401,51935013)资助项目。

摘　　要：微半球谐振陀螺是最具发展潜力的高性能微机电系统(MEMS)陀螺之一,其工作时驱动、检测模态频率需要高度匹配,因此两个工作模态间的频差(频率裂解)是影响陀螺性能的关键因素.机械修调是调节频差的重要手段,其精度决定了模态匹配程度.通过飞秒激光去除质量调节模态频率是一种高效率、高精度的修调方法,但当谐振结构频差处于较小值(约100 mHz)时,观测到线性微质量去除难以进一步降低频差.本文重点针对该过程中的质量-刚度耦合现象开展研究,首先建立了微质量扰动下的质量-刚度耦合变化模型,然后通过有限元模型仿真分析了质量-刚度耦合对修调精度的影响,得到了不同直径与深度修调孔下的微量频差变化,结果揭示了修调孔直径对结构局部刚度的影响规律,以及修调孔深度对局部质量的影响规律.进一步的分析表明,当修调深度超过阈值时能够实现对质量-刚度影响的解耦,因此文中提出了基于质量-刚度解耦的高精度修调方法.最后,对该方法进行了实验验证,将微半球谐振陀螺的频差降低至7 mHz,有效提升了微半球谐振陀螺的机械修调精度.A microhemispherical resonator gyroscope is one of the most promising high-performance MEMS gyroscopes requires frequency matching for the drive and detection modes for its operation.The performance of a microhemispherical resonator gyroscope is largely affected by the trimming accuracy with which the frequency is split between the two operating modes.Mechanical trimming is an important method of tuning the frequency split,and its accuracy determines the degree of modal matching.The modulation of the mode frequency by the method of mass removal using a femtosecond laser is highly efficient and accurate.However,when the frequency split of the resonator is minute(~100 mHz),the removal of linear micromass is difficult to further reduce the frequency split.In this study,we focused on the mass-stiffness coupling phenomenon observed in the frequency splitting process.First,a model of the mass-stiffness coupling variation under micromass perturbation is established.Thereafter,the effect of mass-stiffness coupling on the trimming accuracy is analyzed through finite element model simulation,and the small frequency split variation for trimming holes with varying diameters and depths is determined.The results revealed the influence of trimming hole diameter on local structural stiffness and that of trimming hole depth on local mass.Further analysis indicated that mass-stiffness decoupling can be achieved when the trimming depth exceeds the theoretical critical value;therefore,a high-precision trimming method based on massstiffness decoupling is proposed herein.Finally,experimental verification was performed based on the proposed method.The frequency split of a microhemispherical resonator gyroscope is reduced to 7 mHz,considerably improves the mechanical trimming accuracy.

关 键 词：微半球谐振陀螺 机械修调 质量-刚度耦合 飞秒激光修调 

分 类 号：TH824.3[机械工程—仪器科学与技术]