基于机械波合成的谐振方波钳位式压电马达研究

Piezoelectric motors have wide application prospects in the fields of precision instruments, aerospace, medical technology and so on. However, most of the traditional piezoelectric motors bear severe friction and wear, resulting in the disadvantages of low efficiency and short service life. In this study, macroscopic movement of a piezoelectric motor will be realized in “anchoring/loosening - driven” working mode based on the resonant square wave, which is obtained by the mechanical wave synthesis. This type of piezoelectric motors has a fruitful prospect in solving the problems mentioned above. In addition, the large vibration amplitude and high frequency of the resonance square wave could fully develop the high-frequency/high-density property of piezoelectric elements, and could hereby achieve a high power output. This research proposal focuses on the study of operational strategy, structure design and control system of the motor, and presents a methodology of combining theoretical analysis, numerical calculation, simulation modeling and experimental test. First, the “anchoring/loosening - driven” coupling control mechanism is studied, and a theoretical model is set up. The mechanical wave synthesis mechanism and the resonant square mechanical wave movement with different mechanical structures and different synthesis modes are then summarized. Energy consumption of air friction, vibration damping, impedance matching and energy transfer process will be investigated, and a piezoelectric motor prototype is finally developed. The design and analysis method are also summarized. This research will provide a new way for further practical application of piezoelectric motors.

压电马达在精密仪器、航空航天、生物医疗等领域有着广阔的应用前景。然而，现有压电马达存在摩擦磨损严重、寿命短、效率低等缺点。本项目提出，通过机械波合成得到谐振机械方波，采用基于机械方波的高频谐振“钳位-驱动”工作模式实现压电马达的宏观运动。该类型马达有望解决马达的上述问题；同时，谐振方波振幅大、频率高、能耗低，能够充分发挥压电元件的高频高密度特性，实现高功率输出。本项目拟采用理论分析、数值计算、仿真建模和测试检验相结合的方法，对马达的运行机理、结构设计和控制系统进行研究。首先对“钳位-驱动”控制机理进行分析，建立系统理论模型；其次深入研究非正弦谐振机械波合成机理，掌握不同结构、不同振型实现谐振机械方波输出的规律及方法；再次分析空气阻尼损失、振动能耗、阻抗匹配以及能量传递过程，以提高马达输出性能和效率；最后进行压电马达样机研制，并总结出相关设计和分析方法，为压电马达的进一步实用化提供新思路。

针对压电马达存在摩擦磨损严重、寿命短、效率低等缺点，本项目拟采用理论分析、数值计算、仿真建模和测试检验相结合的方法，对基于谐振机械波合成及单谐波驱动压电马达的运行机理、结构设计和控制系统进行了研究。首先，利用理论分析、三维有限元仿真和实验研究对非正弦谐振机械波合成规律方法进行了深入研究。频率匹配的调整方法的研究，解决了因加工精度误差造成频率比的漂移问题；压电激振的杨氏模量测量方法，避免了传统动态共振测试法使用外延拟合的不足，提高了测量精度，简化了测量过程。掌握不同结构、不同振型实现谐振机械锯齿波、方波输出的规律及方法。其次，利用合成的机械谐振锯齿波、方波，进行了非正弦谐振机械波应用于压电马达研究。不仅验证了锯齿波、方波应用于惯性冲击压电马达和同步钳位压电马达理论的可行性，而且在保证尺蠖式马达较高驱动力输出和精确步距控制特性的同时，充分发挥压电材料的快速响应和高功率密度特性，提高了压电马达的速度、负载等输出性能。最后，进行了单谐波驱动仿生和自钳位压电马达研究。谐波驱动仿生和自钳位压电马达，不仅降低了其摩擦损耗，而且只采用一个压电驱动器，不需要通过模态简并合成椭圆运动，在制造和装配上更简单。此外，电源设计和结构都比传统的压电马达要简单，简化了马达的控制电路，这些优点都有利于压电驱动系统的小型化。目前本项目的研究结果在大天区面积多目标光纤光谱天文望远镜（LAMOST）的扫描驱动系统进行应用尝试。