Design And Analysis Of Anti Overload Piezoelectric MEMS Accelerometer For Vibration Measurement

As a common and important characteristic parameter,vibration signal is one of the main parameters which is monitored by state monitoring system for industrial equipment,large buildings,precision devices and so on.Vibration sensor is among the core parts of the vibration monitoring system,which is used for sensing vibration signal at the most front-end of the vibration monitoring system.Under the background of rapid development of modern science and technology and industrial system,the vibration sensor is required to have better all-round performance,especially the reliability and stability.Therefore,the research and development of new stable,reliable and high-performance vibration sensors suitable for modern vibration monitoring system has become a growing concern,which has a certain significance in improving the performance,efficiency and reliability of the vibration monitoring system.In this paper,a anti overroad piezoelectric MEMS accelerometer for vibration measurement is proposed to meet the practical needs of the development of vibration sensors.The main contents include:(1)A piezoelectric accelerometer for vibration measurement with anti-overload structure in all directions is designed.The accelerometer realizes miniaturization and lightweight based on the technology of MEMS.The accelerometer has a mass-four L-beam sensing structure,which improves sensitivity and reduces transverse interference while obtaining higher natural frequency of the acclerometer.The piezoelectric detection is used to achieve balanced performance of vibration measurement.A three-axis embedded structure to limit displacemet of mass was designed to enhance the anti-overload capability all-around of the acclerometer,which can be fabricated simply.In addition,the accelerometer composed of three-layer structure to achieve self-sealing with wafer-level vacuum packaging and reduce environmental particulate pollution,and improve the reliability and stability of the accelerometer.(2)The theoretical model of the sensitive structure of the accelerometer is established,the structural parameters are theoretically analyzed and optimized by the mathematical tool software MATLAB.The modal analysis,static analysis,overload analysis,dynamic analysis and mechanical-electrical coupling field analysis of the sensitive structure of the accelerometer are carried out by the finite element simulation software ANSYS.Thenatural frequency,static displacement and stress responseand,dynamic frequency characteristics,voltage sensitivity,linearity,transverse sensitivity of the accelerometer are obtained,verify the feasibility of the design.(3)The fabrication process,wafer-level packaging scheme and layout design of the accelerometer are given.The simulation results show that the natural frequency of the piezoelectric vibration accelerometer is 29.8 kHz,the voltage sensitivity is 0.2 mV/g,the transverse sensitivity is 11.25%,and the output linearity is 1.1% at 0-1000 g and 0-6 kHz.