结构解耦的双质量微陀螺仪结构方案设计与仿真

Structural scheme design and simulation of structure-decoupled dual-mass MEMS gyroscope

为了解决双线振动双质量微机械陀螺驱动和检测模态耦合的问题,提出了一种新的双质量双线振动式微机械陀螺仪结构方案,并对驱动和检测梳齿的电容布置以及梁的结构形式进行了设计.根据微陀螺的结构和工作原理,对该陀螺的驱动和检测模态进行了理论分析,给出了简化的动力学方程,并利用ANSYS有限元分析软件进行了数值仿真,以验证设计思想的正确性.仿真结果表明,双质量块和折叠梁的设计使该微陀螺能够实现驱动和检测模态的完全解耦.在仿真验证的基础上,通过调节结构参数实现了陀螺驱动模态与敏感模态固有频率的匹配及其与干扰模态的隔离.2个质量块的差动输出能够有效减小共模信号的干扰,变面积式的梳齿电容布置方式能使微陀螺在空气下的模态品质因数显著提高.该结构设计方案能使微陀螺的整体性能得到提高,达到了理想的设计目的.

A new dual-mass decoupled double-linear vibrational MEMS （microelectromechanical system） gyroscope is proposed to solve the decoupling problem of the driving mode and sensing mode of the gyroscope. The comb capacitances＇ layouts and the beam＇s structures of the gyroscope are also designed. On the basis of the structure and the principle of operation, the gyroscope＇s modals are analyzed in theory, and the simplified dynamic equations are proposed. By using the finite element software ANSYS the modals of the gyroscope has been numerically simulated for the purpose of validating the scheme. The simulation results show that the design of dual-mass and folded-beams can completely realize the decoupling purpose of the driving mode and sensing mode. On the basis of the simulation, the natural frequencies in drive mode and sense mode are matched and also isolated from the interfering modals by adjusting the structure parameters. The two masses＇ differential outputs can effectually decrease the interferences of common mode signals. The alterative cross-areas＇ layouts of comb capacitances can remarkably enhance the modals quality factor of the gyro in the atmosphere. This structural scheme can improve the gyro＇s overall performances and achieve the ideal design purpose.