Systematic experimental based modeling of a rotary piezoelectric ultrasonic motor

In this paper, a new method for equivalent circuit modeling of a traveling wave ultrasonic motor is presented. The free stator of the motor is modeled by an equivalent circuit containing complex circuit elements. A systematic approach for identifying the elements of the equivalent circuit is suggested. The Levenberg-Marquardt parameter estimation algorithm is used to model the alteration of the admittance after placing the rotor on the stator. Thereafter, theoretical assessments and experimental measurements are used to account for the speed reduction that is caused by placing the rotor on the stator and applying the load torque. Finally, the effects of temperature changes and the resultant response of the motor are computed. Results of the experiments and measurements are used to verify and validate the precision of the new modeling method.     

新型惯性式直线超声压电电机的运动机理及实验研究

提出了一种新型惯性式直线超声压电电机.该电机利用压电晶体的逆压电效应和惯性位移原理,由定子的轴向变形,通过摩擦力的作用,以惯性位移的形式传递运动.它由两部分组成,定子由具有位移放大功能的压电复合换能器和轴组成,动子为一带有缺口和环形凹槽的环.分析了该电机的工作原理,并通过仿真和实验相结合的方法分析了两种激励方式对电机性能的影响.实验结果表明:样机采用方波驱动比采用锯齿波驱动的效果好;在采用方波驱动信号驱动时,样机的最大空载速度可达到11 mm/s,最大输出力达到0.5 N.     

叶片式气动马达转速响应特性分析

以一种典型的气动执行元件叶片式气动马达为研究对象,建立了马达的运动学模型,对马达在不同气源压力下的输出转速进行了仿真,通过其输出速度曲线的动态特性参数,分析了马达转速响应特性,为该类马达的结构优化设计奠定了基础。     

Principle and experimental verification of novel dual driving face rotary ultrasonic motor

Existing rotary ultrasonic motors operating in extreme environments cannot meet the requirements of good environmental adaptability and compact structure at same time,and existing ultrasonic motors with Langevin transducers show better environmental adaptability,but size of these motors are usually big due to the radial arrangement of the Langevin transducers.A novel dual driving face rotary ultrasonic motor is proposed,and its working principle is experimentally verified.The working principle of the novel ultrasonic motor is firstly proposed.The 5th in-plane flexural vibration travelling wave,excited by the Langevin transducers around the stator ring,is used to drive the rotors.Then the finite element method is used in the determination of dimensions of the prototype motor,and the confirmation of its working principle.After that,a laser Doppler vibrometer system is used for measuring the resonance frequency and vibration amplitude of the stator.At last,output characteristics of the prototype motor are measured,environmental adaptability is tested and performance for driving a metal ball is also investigated.At room temperature and 200 V(zero to peak) driving voltage,the motor’s no-load speed is 80 r/min,the stalling torque is 0.35 N·m and the maximum output power is 0.85 W.The response time of this motor is 0.96 ms at the room temperature,and it decreases or increases little in cold environment.A metal ball driven by the motor can rotate at 210 r/min with the driving voltage 300 V(zero to peak).Results indicate that the prototype motor has a large output torque and good environmental adaptability.A rotary ultrasonic motor owning compact structure and good environmental adaptability is proposed,and lays the foundations of ultrasonic motors’ applications in extreme environments.     

Analysis and experiments of a novel synchronous PM planar motor with minimized cogging force

We deal with analysis and experiments of a novel moving-coil-type synchronous permanent magnet planar motor (SPMPM) with reduced cogging force. Our previous study assumed that the equation of magnetic flux existing between a permanent magnet (PM) and core was a second-order polynomial, and the minimum cogging force was theoretically and geometrically calculated without FE analysis. In this paper, the cogging force of SPMPM with an iron core is calculated exactly using geometrical factors, which are desired for determining the magnetic flux density. The analytical results of the cogging force using the factors agree well with those obtained by FE analysis and experiment. Several methods for reducing the cogging force of the SPMPM, such as separation and arrangement of the iron core, addition of an extra core, and addition of auxiliary core teeth, are introduced in this paper. Velocity control experiments of the SPMPM with modified and unmodified cores are carried out and the results are compared with each other. The velocity ripple of SPMPM with a modified core is much smaller than that of SPMPM with an unmodified core.     

一种压电步进微动转台的研究

介绍了一种基于尺蠖原理的回转式步进压电微动转台。借助柔性机械结构,将压电陶瓷的微位移以角度方式输送出来。在结构设计方面,采用柔性铰链放大结构,夹紧器和驱动器均采用双驱动器结构,实现推-拉接力运动。配以适当的四路驱动信号,实现了压电微动转台的单步、多步连续匀速转动。最后对样机进行了实验测试。实验结果表明,所设计的压电步进微动转台结构紧凑、分辨力高且运动稳定。同时,动体没有缠绕,使得驱动器可以在任意位置启动,并可在360°范围内连续匀速转动。在频率为5Hz、幅值为30V驱动电压下测得最小步距小于3″,在频率为40Hz幅值为160V的驱动电压下速度达到430.4″/s。     

多振子压电发电机的输出特性

为提高多振子压电发电机的输出能力及有效频带宽度,从理论及试验两方面研究了各压电振子直接串/并联及经整流桥串/并联时的输出电压特性.结果表明,压电振子结构及数量相同时,经整流桥串/并联输出的电压及频带宽度均优于直接串/并联输出的电压及频带宽度,且压电振子经整流桥串联输出方式优于并联输出方式,其电压波动也较小.最后,制作了...     

Static characteristics of gas bearings with a rotary bush

The static characteristics of a gas bearing with a rotary bush are investigated on the basis of an analytical method developed by Sheinberg for a specific bearing structure.     

基于压电陶瓷的微进给平台的实验研究

超精密加工技术是机械制造业中最重要的部分,基于压电陶瓷的微位移机构是近年来发展起来的一种新型微位移机构,设计了基于压电陶瓷为驱动的,以弹性铰链为支撑的微进给平台.并进行了大量的试验,从中得出适于应用的线性电压一位移曲线.采用不同的升降压步长对平台进行驱动,改善了电压一位移的迟滞度.     

经济型变频器的研究

本文采用了单片机PIC16F877和SPWM(Slne Pulse WidthModulation)的技术。提出了一种基于PIC16F877产生的智能控制信号用软件程序去控制SPWM的新方法,设计了一种高效、低成本、功能齐备的小型变频器。     

Concepts for a class of novel piezoelectric self-locking long-stroke actuators

The friction-type motor is the most common type in the field of piezoelectric motors. One limitation of friction-type motors is their inability to achieve high output push force or torque. Based on the theory of self-lock, a novel mechanism for the linear piezoelectric motor is proposed. On the basis of the proposed mechanism, three prototype models have been developed. The new motors transfer the force and displacement generated by a piezoelectric actuator to the output directly, whereas the friction-type motor transfers via the induced friction between the stator and the rotor. The achieved positioning precision is within 10 nm, while the push force is up to 1,176 N. The new motors can be applied in cases where both high positioning precision and heavy load are essential.     

Output characteristics of a series three-port axial piston pump

Driving a hydraulic cylinder directly by a closed-loop hydraulic pump is currently a key research area in the field of electro-hydraulic control technology,and it is the most direct means to improve the energy efficiency of an electro-hydraulic control system.So far,this technology has been well applied to the pump-controlled symmetric hydraulic cylinder.However,for the differential cylinder that is widely used in hydraulic technology,satisfactory results have not yet been achieved,due to the asymmetric flow constraint.Therefore,based on the principle of the asymmetric valve controlled asymmetric cylinder in valve controlled cylinder technology,an innovative idea for an asymmetric pump controlled asymmetric cylinder is put forward to address this problem.The scheme proposes to transform the oil suction window of the existing axial piston pump into two series windows.When in use,one window is connected to the rod chamber of the hydraulic cylinder and the other is linked with a low-pressure oil tank.This allows the differential cylinders to be directly controlled by changing the displacement or rotation speed of the pumps.Compared with the loop principle of offsetting the area difference of the differential cylinder through hydraulic valve using existing technology,this method may simplify the circuits and increase the energy efficiency of the system.With the software SimulationX,a hydraulic pump simulation model is set up,which examines the movement characteristics of an individual piston and the compressibility of oil,as well as the flow distribution area as it changes with the rotation angle.The pump structure parameters,especially the size of the unloading groove of the valve plate,are determined through digital simulation.All of the components of the series arranged three distribution-window axial piston pump are designed,based on the simulation analysis of the flow pulse characteristics of the pump,and then the prototype pump is made.The basic characteristics,such as the pressure,flow and noise of the pumps under different rotation speeds,are measured on the test bench.The test results verify the correctness of the principle.The proposed research lays a theoretical foundation for the further development of a new pump-controlled cylinder system.     

Estimating the characteristics of piezoelectric transducers

A method for estimating the sensitivity of piezoelectric transducers (PETs) is proposed. It is based on normalizing the amplitude of the PET-exciting voltage and calculating the sensitivity with respect to a conventional unit level. The results obtained from measuring PETs produced by well-known foreign manufacturers and at our factory are presented. Attention is also given to measuring the duration of echo signals. The described technique for evaluating the characteristics of echo signals can also be applied to contact angle PETs. The results obtained and proposals put forward in this study can be considered when correcting the Russian Standard for measuring the PET characteristics.Translated from Defektoskopiya, Vol. 41, No. 1, 2005, pp. 20–28.Original Russian Text Copyright © 2005 by Senyutkin, Chineikina.     

悬臂梁式压电换能器能量获取特性研究

研究了悬臂梁式金属-陶瓷压电复合换能器的工作机理,运用有限元理论,借助ANSYS软件建立了压电换能器的有限元分析模型,通过模态分析得到了其固有频率;并且在模型表面施加动载荷,通过瞬态分析,获得了一般环境周期载荷频率和固有频率载荷下换能器的电压输出情况,为今后研究此类换能器的环境吸能特性和可能的应用场合提供了理论依据.     

超声电机宽温域低损耗压电与摩擦功能材料

为了提高超声电机的环境适应性与能量转换效率,本文分析并制造了宽温域低损耗的新型压电材料与摩擦功能材料,提出了通过相结构调控、增加第三组元、引入偶极子缺陷钉扎畴壁等手段制备宽温域低损耗压电陶瓷材料的设计与制造方法;为了提高超声电机摩擦界面能量传递效率及环境适应性,设计了具有高摩擦系数、低磨损率且耐高温的聚酰亚胺复合材料。结果表明,与传统材料相比,新型压电陶瓷材料具有低介电损耗、高机械品质因数及高温度稳定性的优势,使超声电机的能量转换效率提高3.3%,而新型聚酰亚胺基摩擦材料在摩擦系数、耐磨性以及温度范围等指标上均有明显提高,使电机的最大效率提高了6.19%。综合两种新型材料后,超声电机的最大效率提升了13.6%,可靠工作温度从-40~70℃提升至-60~120℃。本文提出的压电与摩擦功能材料既增强了超声电机的环境适应性,也改善了电机输出性能,对超声电机在航空航天等高端装备中的应用具有重要的意义。     

Force and energetic characteristics of a spiral air motor

It is examined whether it is possible to use a spiral volumetric device as an air motor. A mathematical model of a spiral air motor making it possible to calculate its power, torque, and energetic performance is obtained. It is shown that the spiral air motor has better specific characteristics than other types of rotary driving air motors.     

Dynamic optimization of an electromechanical integrated harmonic piezoelectric motor

The coupled dynamic equations for an electromechanical integrated harmonic piezoelectric motor are proposed in this study. The vibration responses of the proposed motor are then determined using these equations. The mathematical models of dynamic optimization are established using the multi-objective optimization method. The optimal parameters are obtained through optimization. The vibration displacements are compared with the initial values. The effects of the parameters on the optimized amplitudes are also investigated. Results show that the vibration displacements of the piezoelectric motor decrease by over 89 % after dynamic optimization. These results can be used to improve the performance and decrease the vibration of the piezoelectric motor.     

一种压电式六维加速度传感器的快速原型及其特性

介绍了一种压电式六维加速度传感器,研究了其敏感单元的布局原理,建立了相应的六维加速度传感方程以实现对6只压电式单轴加速度传感器的输出进行解耦得到刚体运动的六维加速度.在此基础上,采用基于实时仿真系统(dSPACEDS1103和MATLAB/Simulink)的快速控制原型(rapid control prototyping,RCP)技术建立了压电式六维加速度传感器的快速原型.在六维随机振动激励和固定轴旋转振动激励情况下对开发的压电式六维加速度传感器的快速原型的传感性能进行了实验测试.研究结果表明该压电式六维加速度传感器的快速原型能够实现六维加速度的传感,建立的传感方程能够准确地解算出刚体运动的六维加速度.