【作者】 赵学涛；

【导师】 陈维山；

【作者基本信息】 哈尔滨工业大学 ， 机械电子工程， 2007， 博士

【摘要】 超声电机是近三十年发展起来的一种新型驱动器,其工作原理是利用压电陶瓷的逆压电效应和超声振动,将材料的微观变形通过共振放大和摩擦运动转化成转子的宏观运动。目前实际应用的超声电机大多只有直线或旋转一个自由度运动,但在全方位仿生运动的球形关节、机器人柔性关节和眼球以及月球登陆车等领域,都提出具有多自由度运动驱动器的需求,由于超声电机具有结构灵活,运动形式多样的特点,使其比较适合球形转子多自由度驱动的实现。目前国内外对多自由度球型超声电机的研究和应用尚属探索性阶段,现有的多自由度球型电机实现多自由度驱动大多借助几个单方向的独立驱动合成形式,振子之间的驱动作用存在相互阻碍和干扰,导致机械输出特性不够理想。因而对本课题的探索研究,一方面可以为多自由度球型超声电机的研究提供新的思路,奠定理论基础,另一方面也可以拓宽其应用领域,具有很强的现实意义。本文首先从夹心换能器驱动过程的工作原理出发,研究主动纵振和被动弯振耦合关系对换能器驱动性能的影响,以此为依据,采用有限元参数化建模的分析方法,选择对换能器纵、弯振动影响较为敏感的尺寸参数进行总体优化设计。通过有限元方法对优化结果进行分析,验证了优化方法的正确性与可行性。研制了一种基于四换能器协调驱动的球型超声电机,该电机具有结构简单、输出转矩大等优点。球型电机采用了四个相互正交排列的夹心换能器进行协调驱动,通过试验测试出电机的输出特性,最高转速可达到12r/min,最大输出转距为0.45 N·m。设计出十字正交边幅杆构型,为研制单振子多自由度驱动换能器奠定基础。对单振子纵弯换能器的结构参数进行了综合分析,得到各参数对换能器特征频率的影响趋势,为实现纵弯模态简并做准备。利用有效机电耦合系数确定压电陶瓷位置,并给出激励换能器驱动足质点产生三种正交椭圆轨迹的激励方法。采用有限元瞬态运动分析方法,对换能器驱动足质点椭圆轨迹进行了研究,建立了驱动质点运动轨迹的关键图谱。研制了一种基于单振子纵弯换能器驱动的多自由度球型超声电机,该电机具有绝对输出转矩大、驱动简单和控制性能好等优点。电机输出性能指标为:绕X、Y轴旋转时,输出转距为0.97 N·m,最高转速可达11r/min,绕Z轴旋转时,输出转距为0.27 N·m,最高转速可达66r/min。更多还原

【Abstract】 Ultrasonic motor (USM) is a new kind actuator developed during recent three decades, which transform micro displacement into macro motion of rotators via resonant amplifying and frictional effect by using converse piezoelectric effect and ultrasonic vibration. Presently, almost all the practically used USM have only one degree of freedom (DOF), such as linear or rotary movement. However, special actuators realizing multi-degree of freedom motion (multi-DOF) are in great demand in the area of ball-shape bionic joints, flexible joints and eye balls of rotots and moon explorer vehicles. Due to the structure flexibility and multi motion way, USMs are suitable to realizing multi-DOF motion. The research on the structure and application on the multi-DOF USM in the world is in the investigating stage until now. The existing multi-DOF USMs realize multi-degree of freedom motion by superimposing several independent actuation, then impediment and interference occurs leading to an unsatisfactory mechanical output. The research on this topic can bring forward new thinking and build theoretical foundation for multi-DOF spherical USM. Meantime, the application area of multi-DOF USM can be broadened with significant practical meaning.Based on the Langevin transducer driving process and working principle, this dissertation carried out research on the coupling relation of active longitudinal and passive bending vibration on transducer driving performance. By adopting parametric finite element method (FEM), those dimension parameters, which were more sensitive to transducer longitudinal and bending vibration, were selected to perform optimization design. The optimization method was verified to be correct and feasible by analyzing the optimization results using FEM.A quadric transducer coordinately driving spherical USM was proposed and fabricated. This kind of USM has merits such as simple structure and high output torque. The spherical USM actuated through driving four orthogonally arranged Langevin transducer coordinately. The output mechanical properties were tested by experiment, and the maximum rotary speed is 12r/min, the maximum output torque is 0.45 N·m.A cross orthogonal horn was proposed to build foundation for study single vibrator multi-DOF transducer. Comprehensive analysis was carried out on structure parameters of the single vibrator longitudinal-bending transducer, thereby the parameters’influence tendency towards the eigenfrequencies was got to realize longitudinal-bending modal degeneration. Positions of piezoelectric ceramics were determined by using effective electromechanical coupling factor. The exciting way of getting three type orthogonal elliptical trajectories on the particle of the driving foot was proposed. The investigation of elliptical trajectories of the driving foot particle was performed through transient analysis of FEM.A multi-DOF spherical USM based on single longitudinal-bending transducer vibrator was proposed and studied. This kind of USM has merits such as high output torque, simple driving and easy controllability. The output mechanical properties were as follows: when revolving around X and Y axis, the output torque was 0.97 N·m and the maximum rotary speed was 11r/min; when revolving around Z axis, the output torque was 0.27 N·m and the maximum rotary speed was 66r/min.更多还原