基于面内弯纵复合模态的直线超声电机研究

发布时间：2018-06-13 08:34

本文选题：超声电机 + 直线电机　；参考：《哈尔滨工业大学》2014年博士论文

【摘要】：超声电动机是近三十多年来发展起来的一种全新概念的驱动装置。与传统电磁电机相比，超声电机具有结构简单、能量密度大、启停灵敏、位置分辨率高、断电自锁、低振动、低噪声、无电磁干扰等特点。所以它在航天器、微小型机械、精密仪器、小功率驱动等方面的应用具有明显的优越性。直线超声电机是超声电机的一个分支，它通过定子和滑块（或者动子）之间的摩擦耦合输出直线运动和推力。由于其结构简单，可以直接输出直线运动，不需要运动转换机构，所以除了具有旋转型超声电机的一般特点外，直线超声电机的定位精度和速度控制精度更高，可达纳米级精度。本文提出了一种新型面内弯纵型直线超声电机。该电机的定子由一块青铜矩形板和八片压电陶瓷片组成，电机利用矩形板的面内二阶弯曲振动和一阶纵向振动的复合模态来工作。由于矩形板的宽度远小于厚度，其面内弯曲振动难以被激发，所以，本研究中，在青铜矩形板的适当位置开设了若干长条形孔来解决这个问题，并利用瑞利-里兹法确定了长条形孔的最佳长度尺寸。在电压信号的激励下，压电陶瓷片产生超声频率的伸缩振动，并激发出矩形板定子的面内弯纵复合模态，使矩形金属板产生共振，并使矩形板上的驱动足产生椭圆运动。通过摩擦耦合将驱动足的椭圆运动变成电机滑块的直线运动，从而实现直线电机的动力输出。分析了压电材料的逆压电效应，从矩形板定子面内二阶弯曲振动和一阶纵向振动的振动方程出发，建立了矩形板定子的机电耦合动力学模型，计算了压电陶瓷片对定子所施加的面内二阶弯曲振动和一阶纵向振动的模态力，给出了若干压电陶瓷片的合理安装位置，解释了定子驱动足椭圆运动的形成机理。应用有限元分析软件建立了面内弯纵型直线电机定子的有限元模型，对电机定子进行全面的仿真分析，包括模态分析、谐响应分析、瞬态动力学分析和接触分析。通过仿真，得到了定子的振型，优化了电机的结构尺寸，计算了定子产生面内纵弯复合振动时的最佳频率，验证了定子驱动足的椭圆运动的形成机理，比较了矩形板开孔前后定子的振幅、频率等变化，，并通过接触分析证明了这种直线超声电机设计方案的可行性。课题对弯纵型直线超声电机进行驱动和摩擦分析，从定子驱动足质点的椭圆运动研究入手，以新的视角分析了驱动足质点的椭圆运动对动子运动的驱动和阻碍机理，提出了定子质心位置和定子两端的作用力随着定子的振动而变化的观点。在此基础上，分析了定子和动子摩擦界面间的粘、滑摩擦机理，指出驱动足对动子的驱动方式为跳跃式驱动，且定子驱动足相对于动子适当的“跳跃”有利于电机的动力输出，还指出定子驱动足的“跳跃”高度取决于预压弹簧刚度、动子摩擦层的刚度、电机预压力、驱动足振幅等因素。为验证本课题所设计和制造的新型超声电机合理性和可行性，加工制作了直线超声电机的样机，搭建了实验平台并进行了相关的实验。在实验中，对定子矩形板是否开孔两种情况进行了比较实验，证明矩形板开孔后可以扩大定子的振幅，特别是面内弯曲振动的振动幅度，并且电机的输出速度和最大输出力明显加大。
[Abstract]:Ultrasonic motor is a new concept driving device developed in the past thirty years. Compared with the traditional electromagnetic motor, ultrasonic motor has the characteristics of simple structure, high energy density, high position resolution, high position resolution, low vibration, low noise, and no electromagnetic interference. So it is in spacecraft, micro machine, precision instrument. The linear ultrasonic motor is a branch of the ultrasonic motor, which outputs the linear motion and thrust through the friction coupling between the stator and the slider (or the motion). Because of its simple structure, it can directly output the linear motion without the need of motion conversion mechanism, so in addition to it The general accuracy of the rotary ultrasonic motor is that the accuracy and speed control accuracy of the linear ultrasonic motor is higher, and it can reach nanometer accuracy.
In this paper, a new type of in-plane curved longitudinal linear ultrasonic motor is proposed. The stator of the motor is composed of a bronze rectangular plate and eight piezoelectric ceramic plates. The motor uses the composite mode of the two order bending vibration and the first longitudinal vibration in the surface of the rectangular plate. The bending vibration of the rectangular plate is difficult to be subjected to the thickness of the plane. In this study, a number of long strip holes are set up in the proper position of the bronze rectangular plate to solve this problem, and the optimum length size of the long strip hole is determined by Rayleigh Ritz method. Under the excitation of the voltage signal, the piezoelectric ceramic plate produces the ultrasonic vibration of the ultrasonic frequency and excites the inner bending of the rectangular plate stator. The combined mode makes the rectangular metal plate resonate and causes the elliptical motion of the driving foot on the rectangular plate. Through the friction coupling, the elliptical motion of the driving foot is transformed into the linear motion of the motor slider, thus the power output of the linear motor is realized.
The inverse piezoelectric effect of the piezoelectric material is analyzed. Based on the two order bending vibration and the first order longitudinal vibration equation of the rectangular plate stator, the electromechanical coupling dynamic model of the rectangular plate stator is established. The modal forces of the two order bending vibration and the first longitudinal vibration of the stator are calculated, and some of the modal forces of the first order longitudinal vibration are calculated. The reasonable installation position of the piezoelectric ceramic plate explains the formation mechanism of the elliptical motion of the stator driving foot.
Finite element analysis software is used to establish the finite element model of the stator of an inner curved longitudinal linear motor. The stator of the motor is simulated and analyzed comprehensively, including modal analysis, harmonic response analysis, transient dynamic analysis and contact analysis. Through simulation, the stator vibration mode is obtained, the structure size of the motor is optimized, and the stator production surface is calculated. The optimum frequency of the longitudinal bending combined with vibration proves the formation mechanism of the elliptical motion of the stator driving foot, and compares the amplitude and frequency of the stator before and after the opening of the rectangular plate, and the feasibility of the design of this linear ultrasonic motor is proved by contact analysis.
In this paper, the driving and friction analysis of a curved longitudinal linear ultrasonic motor is carried out. Starting with the study of the elliptical motion of the particle driven by the stator, the driving and blocking mechanism of the elliptical motion of the driving foot particles is analyzed with a new angle of view. The position of the stator center of mass and the force of the two end of the stator change with the vibration of the stator. On this basis, the viscosity and sliding friction mechanism between the stator and the rotor friction interface is analyzed. It is pointed out that the driving mode of the driving foot is hopping, and the appropriate "jumping" of the stator driving foot is beneficial to the power output of the motor. It also points out that the "jump" height of the stator driving foot depends on the preloading spring stiffness. The stiffness of the friction layer, the preload of the motor, and the amplitude of the driving foot are all factors.
In order to verify the rationality and feasibility of the new ultrasonic motor designed and made in this project, a prototype of a linear ultrasonic motor is manufactured, the experimental platform is built and the related experiments are carried out. In the experiment, two cases of the stator opening are compared. It is proved that the amplitude of the rectangular plate can expand the amplitude of the stator after opening the hole. Especially the vibration amplitude of the bending vibration inside the plane, and the output speed and the maximum output force of the motor obviously increase.
【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM35

【参考文献】