静电负刚度谐振式加速度计的非线性振动特性研究

Nonlinear Vibration Characteristics of the Electrostatic Negative Stiffness Resonant Accelerometer

为了进一步探究微机电系统(MEMS)传感器领域中静电力对非线性振动的影响,以静电负刚度谐振式加速度计(ENSRA)为研究对象进行动力学建模和实验分析。基于哈密顿原理建立了ENSRA机电耦合的非线性振动动力学模型,分析了其高阶非线性刚度的来源,并结合实验现象探究了MEMS传感器中静电力对器件非线性振动的影响,得到了驱动力与静电力对高阶非线性刚度的一般关系。经过开环扫频实验表明,当驱动力从100mV降低到60mV时,非线性振动优化了49%,当调谐电压从10V降低到6V时,非线性振动优化了44%,输出非线性降低了将近4个数量级,器件整体性能大幅提升,有效改善了二阶非线性刚度项导致的谐振器刚度软化和谐振峰的左偏现象。

In order to further explore the influence of electrostatic force on nonlinear vibration in the field of MEMS sensors,this paper takes the electrostatic negative stiffness resonant accelerometer(ENSRA)as the research object to carry out dynamic modeling and experimental analysis.Based on Hamilton principle,the electro-mechanical coupling nonlinear vibration dynamic model of ENSRA is established,and the source of its high-order nonlinear stiffness is analyzed.Combined with experimental phenomena,the influence of electrostatic force on the nonlinear vibration of MEMS sensor is explored,and the general relationship between driving force and electrostatic force on the high-order nonlinear stiffness is obtained.The open-loop frequency sweep experiment shows that when the driving force is reduced from 100mV to 60mV,the nonlinear vibration is optimized by 49%,and when the tuning voltage is reduced from 10V to 6V,the nonlinear vibration is optimized by 44%.The output nonlinearity is reduced by nearly four orders of magnitude,and the overall performance of the device is greatly improved,effectively improving the stiffness softening of the resonator and the left deviation of the resonant peak caused by the second-order nonlinear stiffness term.