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为了减小正交误差对硅MEMS陀螺仪性能的影响,进一步提高陀螺精度和工程化成品率,对MEMS陀螺正交耦合的影响因素进行了研究。通过MEMS陀螺的运动学简化模型,分析了正交耦合的起因;计算了MEMS陀螺的静电驱动力和阻尼系数,建立了MEMS陀螺有限元参数化模型,利用谐波分析模拟了陀螺在驱动模态下的运动状态;在谐波分析的基础上,研究了不同误差来源对正交耦合的影响。结果表明:侧壁垂直度误差不是正交耦合的起因;科氏质量重心偏移对正交耦合的影响很小,即使在误差敏感方向上,正交耦合系数的敏感度也只有0.0032%/μm;振动结构支撑梁的加工误差是引起结构刚度不对称并产生正交耦合的主要因素,其中正交耦合系数对梁宽误差的敏感度可达2.15%/μm(梁宽误差为±0.1μm),对梁倾斜误差的敏感度高达16%/(°)(梁角度误差为±0.05°)。
In order to reduce the influence of quadrature error on the performance of silicon MEMS gyroscope, further improve the accuracy and engineering yield of gyroscope, and study the influence factors of orthogonal coupling of MEMS gyroscope. Based on the simplified kinematics model of MEMS gyroscope, the origin of orthogonal coupling is analyzed. The electrostatic driving force and damping coefficient of MEMS gyroscope are calculated. The finite element parametric model of MEMS gyroscope is established. By using harmonic analysis, Based on the harmonic analysis, the influence of different error sources on the orthogonal coupling is studied. The results show that the error of the verticality of the sidewall is not the cause of the orthogonal coupling. The offset of the center of mass of the Coriolis mass has little effect on the orthogonal coupling. Even in the error-sensitive direction, the sensitivity of the orthogonal coupling coefficient is only 0.0032% / μm The machining error of the vibrating structure support beam is the main factor that causes the structural stiffness asymmetry and the orthogonal coupling. The sensitivity of the orthogonal coupling coefficient to the beam width error is up to 2.15% / μm (the beam width error is ± 0.1 μm) , The sensitivity to beam tilt error is as high as 16% / (°) (beam angle error is ± 0.05 °).