Dynamic stability of parametrically-excited linear resonant beams under periodic axial force

The parametric dynamic stability of resonant beams with various parameters under periodic axial force is studied.It is assumed that the theoretical formulations are based on Euler-Bernoulli beam theory.The governing equations of motion are derived by using the Rayleigh-Ritz method and transformed into Mathieu equations,which are formed to determine the stability criterion and stability regions for parametricallyexcited linear resonant beams.An improved stability criterion is obtained using periodic Lyapunov functions.The boundary points on the stable regions are determined by using a small parameter perturbation method.Numerical results and discussion are presented to highlight the effects of beam length,axial force and damped coefficient on the stability criterion and stability regions.While some stability rules are easy to anticipate,we draw some conclusions:with the increase of damped coefficient,stable regions arise;with the decrease of beam length,the conditions of the damped coefficient arise instead.These conclusions can provide a reference for the robust design of parametricallyexcited linear resonant sensors.     

基于单晶硅材料的微摩擦测试机构及其试验研究

设计出1种能够模拟基于单晶硅材料微机电器件侧面摩擦副摩擦磨损状况的试验机,有效模拟可动MEMS器件摩擦副之间磨损的真实状况,介绍了试验机测试机构的工作原理并从理论计算及有限元模拟分析2方面对其结构模态进行分析,在超净间内(千级、室温、相对湿度RH约50%),利用光学显微镜、CCD图像采集系统及计算机对梳齿驱动器的谐振频率及摩擦副的动态摩擦系数进行了测试.结果表明:采用所研制的试验机测得的谐振频率为5 600,与理论计算及模拟分析的结果(5 590和5 641)非常接近;摩擦副的动态摩擦系数在0.24～0.35之间;动态摩擦系数随着施加在摩擦副上的正压力变化而变化.     

Dynamic characteristics of resonant gyroscopes study based on the Mathieu equation approximate solution

Dynamic characteristics of the resonant gyroscope are studied based on the Mathieu equation approximate solution in this paper.The Mathieu equation is used to analyze the parametric resonant characteristics and the approximate output of the resonant gyroscope.The method of small parameter perturbation is used to analyze the approximate solution of the Mathieu equation.The theoretical analysis and the numerical simulations show that the approximate solution of the Mathieu equation is close to the dynamic output characteristics of the resonant gyroscope.The experimental analysis shows that the theoretical curve and the experimental data processing results coincide perfectly,which means that the approximate solution of the Mathieu equation can present the dynamic output characteristic of the resonant gyroscope.The theoretical approach and the experimental results of the Mathieu equation approximate solution are obtained,which provides a reference for the robust design of the resonant gyroscope.     

新型谐振式微机械陀螺设计与仿真

新型微机械陀螺采用了谐振敏感原理,其具有直接准数字式频率输出、高灵敏度、高线性、自解耦等优点.结构包括内外质量块、支撑梁、折叠梁、两级杠杆放大机构、双端固支音又(DETF),质量块驱动梳齿、质量块反馈检测梳齿、DETF驱动和检测梳齿.采用了两级杠杆放大机构、质量块外置、框架结构等措施来提高陀螺的性能.从仿真结果可以看出,传感器灵敏度为0.309 Hz/(deg·S-1).测量范围为±300deg/s,在测量范围内,线性度为9.4×10-1.驱动方向上DETF的振幅减到外质量块振幅的2.96×10-6倍,说明陀螺具有很好的自解耦功能.     

一种谐振式硅微机械陀螺的设计和加工

基于谐振式检测方式的高灵敏度、大动态范围、易于与数字电路接口等优点,提出了一种谐振式微机械陀螺的新型结构,研究了其工作原理,得到了双端音叉谐振器(DETF)振动Mathieu方程的稳态输出,并基于此稳态输出的贝塞尔曲线簇分解信号的幅相频率特性曲线进行了特性分析和Matlab仿真研究,从而提出了一种利用DETF输出信号xr中ωr0或ωr0 ωp频率分量来解算科氏力的方法,实现对输入角速度?的检测,并采用SOG工艺加工此新型结构得到样件。研究表明,此新型谐振式硅微机械陀螺结构具有准数字输出,并能有效提高其输出信号的信噪比。