微机械振动陀螺模态耦合误差分析与激光修形方法研究

摘要

较大的模态耦合误差严重影响陀螺仪的零偏稳定性.研究了一种微机械振动陀螺仪的模态耦合误差形成机理,仿真分析了结构加工误差对模态耦合误差的影响规律.仿真结果表明:振动结构支撑梁上的加工误差是引起结构刚度不对称并产生模态耦合误差的主要因素,在与该加工误差对称的位置去除相应的材料可以减小甚至消除模态耦合误差.采用紫外激光微细加工技术,对微陀螺样机进行了结构平衡实验,激光修形后在没有输入角速度时,微陀螺样机模态耦合误差信号的峰峰值从2.88V降低到0.24V,取得了明显的修形效果.%Large modal coupling error seriously influences zero-offset stability of gyroscope. The formation mechanism of modal coupling error of a micromachining vibration gyroscope is studied, and the effect rule of structural machining error on modal coupling error is simulated. Simulation result shows that machining error on the support beam is the major factor contributing to the dissymmetry of structural stiffness that results in modal coupling error,and the modal coupling error can be to decreased or even eliminated by removing corresponding material in the symmetrical location. Structural balance experiment is implemented on the microgyroscope by UV laser micromachining technology, when there is no angular velocity inputs after laser trimming, the peak-peak voltage of the modal coupling error signal of microgyroscope is reduced from 2. 88 V to 0. 24 V, trimming effect is obvious.