Actuation Mechanism And Application Research On Piezoelectric MEMS

Micro-Electro-Mechanical System(MEMS),has become an increasingly concerned research hotspot in the field of electronic information in today's miniaturization and integration of electronic devices.With the continuous emergence and popularization of new materials and technologies,piezoelectric micro-electromechanical systems(Piezo-MEMS),with their unique piezoelectric characteristics,high response speed,small size and low cost,have promoted the rapid development of miniaturized applications such as micromechanical sensors,actuators and transducers.In the application of piezoelectric microelectromechanical systems,the micromechanical structure that realizes energy conversion based on positive and negative piezoelectric effect,is the core of the entire system to achieve both high performance and miniaturization.The design of ingenious micro-mechanical structure improves the sensitivity,output performance and reliability of the device,reducing the energy loss of the system.Piezoelectric micromechanical structures and electromechanical transduction mechanisms follow the objective laws of mechanical and electrical behavior of elastomers and dielectrics,meeting the requirements for the feasibility of miniaturized systems.It is effective solutions for integrated microsystems.The mature piezoelectric microelectromechanical system is centered on miniaturization and integration,which strengthens some core indicators,taking design demonstration,processing and manufacturing,and packaging integration into a systematic research.Therefore,this dissertation is guided by the actuation mechanism of piezoelectric micro-electromechanical systems.Based on the theory of piezoelectric actuation,the device performance is correlated with the corresponding structural parameters to optimize the micromechanical structure.The design index is verified and iteratively optimized through device manufacturing and experimental testing to complete the miniaturization and integration of the device and achieve the design goals.This dissertation has carried out research work on the related technologies of piezoelectric microelectromechanical systems.The main contents are:First,a piezoelectric multi-axis micro-vibration platform is proposed,which can be applied for self-calibration of inertial sensors.Based on the bending vibration model of the single-ended fixed beam,the vibration characteristics and the dependence of main performance indexes of the micro-vibration platform is obtained.A micro-vibration platform structure with a length of 3 mm based on four folded beams is designed.The output performance of the device is improved through the analysis of structural parameters.The fabricated and packaged micro-vibration platform has achieved the performaces of a maximum displacement of 59 ?m,an axial maximum acceleration of 40 g,a maximum tilting angle of 0.45 ° and a maximum tilting angular velocity of 3000 °/ s.A motion monitoring scheme based on optical principles is designed and integrated.The in-situ self-calibration of the inertial sensor is achieved through closed-loop control.Within 15 g of the inertial sensor range,the calibration error is less than 1.17%.Secondly,a new type of flattened piezoelectric traveling wave ultrasonic micromotor is proposed,which can be applied for step motion control of ultrasonic micromotor.Based on the circular thin-plate out-of-plane vibration model,the generation principle and excitation conditions of traveling waves are studied.A new type of stator actuator with an outer diameter of 4 mm which has rectangular notches to set the support structures at the places witn zero displacement is designed.Through the study and optimizion on the structure of the stator actuator,a micromotor stator based on a flexible supporting structure is obtained to achieve high matching of traveling wave.A scheme for applying a preload force between the stator and the rotor by magnetic force is designed.Under the control of the adjustable magnetic preload force,the micromotor has achieved a maximum speed of 8906 rpm and a maximum torque of 27.03 ?Nm at a resonance frequency of 100.1 kHz.A capacitive motion monitoring scheme is designed to realize the stepping rotation control of the micromotor.At a step angle of 22.5°,the rotation error is less than ±0.3°.In summary,the research in this dissertation is from the perspective of system design,taking the theory and experiment into combination.Based on the dielectric piezoelectric effect and the basic principles of elastic body vibration mechanics,two types of piezoelectric microelectromechanical systems are studied.One is a piezoelectric multi-axis micro-vibration platform that can be used for self-calibration of inertial sensors.The other is a flat piezoelectric traveling wave actuator that can be used for micromotor stepping motion.These research contents enrich and expand the related theoretical and applied research of piezoelectric microelectromechanical systems.