圆盘型非接触压电微马达定子的振动分析

提出一种圆盘型非接触压电微马达,采用有限元方法分析了马达定子的振动模态和固有频率,对定子的振幅与施加电压的关系进行了数值分析。最后,采用激光多谱勒测振仪对定子的振型和振幅进行了测试,实验结果与有限元分析吻合较好,为马达定子的设计和优化提供了理论依据。     

新型行波压电电动机的结构研究及理论分析

环型和圆盘型行波压电电动机小直径条件下,输出性能逐渐失去低速大力矩的特点。由于结构限制,其定转子的动态点接触导致电动机运转不平稳、磨损大和驱动力矩小等不足。针对这些不足提出一种新型行波柱面驱动压电电动机,将传统的点接触改进成现在的线接触,即环型或圆盘型定子改进成圆柱型定子。阐述了行波压电电动机的运行机理以及电动机驱动系统原理。通过对压电电动机定子结构的振动理论分析,证明此新型结构电动机符合一般压电电动机形成驱动及正常工作的基本条件。利用ANSYS有限元软件分析电动机定子的振动模态, 给出选取振动模态的理论依据。制作了直径为20 mm的柱面驱动压电电动机,并对其输出特性进行测试,得到测试结果为输出力矩／质量比是0．426。     

基于谐波分析的叉车振动研究

为解决工作状态下叉车司机座椅与方向盘振动强烈的问题,采用有限元分析与实际加速度测试相结合的方法,通过实验结果与有限元结果的对比和修正,得到符合实验结果的仿真模型.经对该模型的谐波分析表明,叉车司机座椅和仪表盘的固有频率与发动机激励频率相差较大,显示为振动的强迫性而非共振性.     

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.     

非接触压电微马达的仿真与实验研究

提出了一种基于四区和八区2种激振方式的新型非接触压电微马达,并进行了振动模态的有限元数值模拟。利用ANSYS有限元软件对定子进行模态分析,并用激光测振仪对四区和八区2种激振方式下的定子进行位移扫频和振型测试,得出:最优驱动频率分别为34.4 kHz和46.3 kHz,相应的模态分别为B₂₁和B₂₂,二者结果吻合较好。对微马达的输出性能进行了实验研究,结果表明:三叶片和六叶片转子在八区最优模态激振下转子的转速约是四区的2倍。说明了增加定子的分区数不仅改变了定子的最优驱动频率而且能够明显提高转子的转速。而且当A-B间相位差从90°调谐到270°时,行波的传播方向发生了改变,从而实现了转子的换向。实验还表明,转子的正反转的转速基本一致。     

宏微直线压电电机微驱动机构设计与分析

为了解决宏微驱动直线压电电机微驱动位移较小、对宏动定位误差的补偿能力不足的问题,提出一种宏微驱动钹型直线压电电机。采用钹型复合压电叠堆为驱动单元替换压电陶瓷片组成的压电叠堆,实现轴向位移的一次放大,通过弹性拨齿的柔性铰链结构将钹型压电叠堆输出的微位移二次放大。该电机可在特定的驱动频率、工作电压和相位差下实现振子振动模态下的超声驱动,也可以通过微位移放大机构实现静态变形的微驱动(蠕动)。建立了该直线压电电机的三维有限元模型,利用有限元软件分别对弹性拨齿、钹型压电叠堆和复合振子进行静力学分析和静态优化设计。有限元仿真表明:基于柔性铰链结构的弹性拨齿经过优化后,最小刚度小于钹型压电叠堆的最小刚度;在相同条件下,优化后钹型压电叠堆沿轴向方向的静态变形量比由压电陶瓷片组成的压电叠堆的静态变形量提高了8.45倍;采用基于柔性铰链结构的弹性拨齿和钹型压电叠堆组成的复合振子的拨齿质点沿水平方向的静态位移量比优化前提高了12.1%,大幅提高了微驱动对宏动定位误差的补偿能力,为压电电机微驱动的结构设计及优化提供依据。     

ANSYS在超声波电机设计中的应用

为获得超声波电机的振动模态及谐响应特性,采用ANSYS有限元软件对直径为60mm的环形行波型超声波电机定子的振动状态进行了分析;在完成超声波电机定子建模的基础上,进行了电机定子的振动模态分析和最优模态选择,并在此最优模态附近进行了谐响应分析。分析研究结果表明,利用ANSYS软件对超声波电机进行分析被证明是一种行之有效的方法。     

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.     

超声切割用压电换能器理论设计及有限元仿真

基于波动方程和频率方程,建立了电镀金刚石线锯超声切割用压电换能器的解析模型,得到了压电换能器各组成部分的结构尺寸。借助有限元分析软件ANSYS对理论设计的压电换能器进行了动力学分析和优化设计,得到了压电换能器的优化模型。分析结果表明,有限元法对压电换能器的设计和分析具有很好的指导作用。这种换能器具有良好的性能,对下一步的应用研究有重要意义。     

Finite element modelling for a piezoelectric ultrasonic system

In this paper, a three-dimension (3-D) mechanical element with an extra electrical degree of freedom is employed to simulate the dynamic vibration modes of the linear piezoelectric, piezoelectro-mechanic and mechanical behaviors of a metal disc structure embedded with a piezoelectric actuator. In piezoelectric finite element formulation, a discretized equation of motion is developed and solved by using the integration scheme to explain why an adaptive boundary condition, a simple support condition with three non-equal-triangular (120°–90°–150°) fixed points near the edge, which is the asymmetric disc used as the stator of the studied ultrasonic motor, for the mechanical design of an asymmetric disc-type piezoelectric ultrasonic stator, is defined so that a lateral elliptical motion of the contact point between stator and rotor can be realized for driving the rotor. It starts from hybrid elements with displacement and electric potential as the nodal d.o.f.s model and uses Guyan reduction and Householder-Bisection inverse iteration to find the displacement profile and displacement vector flow of the stator under frequency driving. The standing wave existence is also proven by the displacement patterns of the finite element theoretical model.     

多层波纹管动态刚度的影响因素研究

采用有限元分析软件对多层无加强U型波纹管的动态特性进行了分析。利用参数化设计语言(APDL)建立了波纹管有限元模型并对其进行模态分析,分析了含夹层阻尼的多层波纹管的几何参数,如波纹管的波高、波距、直径、壁厚等对波纹管动态刚度的影响及其变化规律。通过振动试验,验证了有限元分析结果的正确性,其结果对波纹管的设计研究提供了一定的参考依据。     

一种用于鸭翼控制的摇头型双圆环压电马达研究

针对制导弹药平台对舵机的紧凑、直驱等要求,提出了一种采用夹心式换能器诱发双圆环弯曲振动的复合型压电定子结构,由此可构成结构精巧的摇头型双圆环旋转压电马达,用以驱动鸭式舵翼产生特定的偏转运动。该马达中的复合定子主体为一个具有四片压电陶瓷片的夹心式换能器,分别在换能器两输出端设计了利于放大振幅的环形圆盘;夹心式换能器的摇头运动激励出两端环形圆盘的五阶弯曲模态,通过圆环将输出振幅进一步放大;两个圆盘形转子在一定的预压力作用下与复合型压电定子两端的圆环表面保持紧密接触,通过摩擦将圆环表面的椭圆轨迹转换为转子的旋转运动。设计了可用于某制导系统鸭舵偏转操纵的直驱马达结构,建立了基于夹心式换能器的双圆环形定子结构动力学模型,通过有限元软件对定子的模态进行了仿真分析,设计并加工出了样机。搭建了测试平台对样机的输出特性进行了实验,测试结果表明：该双圆环（双）输出轴马达可实现双输出轴同时旋转,在300 V峰峰值的驱动电压下,最大转速可达190 r/min,最大输出扭矩可达0.07 N·m。     

Dedicated algorithm and software for the integrated analysis of AC and DC electrical outputs of piezoelectric vibration energy harvesters

DC electrical outputs of a piezoelectric vibration energy harvester by nonlinear rectifying circuitry can hardly be obtained either by any mathematical models developed so far or by finite element analysis. To address the issue, this work used an equivalent electrical circuit model and newly developed an algorithm to efficiently identify relevant circuit parameters of arbitrarily-shaped cantilevered piezoelectric energy harvesters. The developed algorithm was then realized as a dedicated software module by adopting ANSYS finite element analysis software for the parameters identification and the Tcl/Tk programming language for a graphical user interface and linkage with ANSYS. For verifications, various AC electrical outputs by the developed software were compared with those by traditional finite element analysis. DC electrical outputs through rectifying circuitry were also examined for varying values of the smoothing capacitance and load resistance.     

振动打桩机偏心块的参数研究与有限元分析

以激振力为10t的振动打桩机激振器为例．针对常用的几种半圆式偏心块结构．从理论上获得其结构参数．并运用Solid Works机械设计软件建立模型．在此基础上使用有限元分析软件COSMOS/Work对其进行结构分析和有限元计算．得到弯角武偏心块比直角式偏心块承受的应力小．在恒定离心力作用下刚度和安全系数太装配弯角偏心块强度和承载能力最好．并便于拆装和移运等结论，为改进设计和现场使用提供了理论依据。     

Vibration reduction of automotive transmission control cables

A reduction in the level of vibration in the gearshift lever module in the cabin of automobiles may have a positive effect on driver comfort. The vibration to the gearshift lever module is transferred through transmission control cables (TCCs) connected to the shift lever attached to the body of a transmission or transaxle. Ways to reduce vibrations are evaluated by analyzing vibration characteristics of TCCs employed in conventional gearshift lever modules. The analysis was carried out by both analytical and experimental approaches, including the construction and analysis of a finite element model of the module. By utilizing the results from the analysis, a vibration reduction method was proposed and its applicability was also investigated. It is observed from the investigation that the proposed method is a viable solution for both the reduction of vibration-related issues in gearshift level modules and improvement of ride quality.     

气体挤压膜轴承的性能分析及其控制器的研究

为了有效克服传统气体轴承的缺点,基于超声激励的气体挤压膜机理,研制了一种新型的气体挤压膜轴承。为了获得关键结构尺寸及相关的控制参数,采用有限元法对压电换能器进行了模态分析和谐响应分析;应用数值解法从理论上证明了轴承的悬浮能力;通过压电换能器的模态实验,确定了其工作频率;同时采用有限元法对所设计的轴承产生的超声波声压进行了分析。在此基础上,设计制作了基于STC单片机的数字控制器硬件电路,编写了不完全微分PID控制程序并在实验台上进行了验证。研究结果表明,该类轴承在超声激励下能够实现悬浮支承。     

圆锥型压电换能器的动态设计与实验研究

对一种圆锥型夹心式压电换能器进行了动态设计与实验分析。利用有限元分析方法对换能器进行了动态设计,给出了该类压电换能器有限元建模方法,分析了换能器主要结构尺寸对振动模态、固有频率的影响。依据有限元分析结果,提出了一种基于数值分析的换能器优化设计方法,简化了设计过程。在数值分析的基础上,设计、研制了圆锥型夹心式压电换能器,并对压电换能器进行了性能测试。并将实验测试数据和有限元分析结果进行了对比,测试结果验证了数值分析与设计方法的合理性。     

Simulation analysis of cogging torque of permanent magnet synchronous motor for electric vehicle

This paper proposes a new approach to study generation mechanism and influence factors of cogging torque of permanent magnet synchronous motors, in order to improve the operational performance and riding comfort of electric vehicle. Based on energy method and Fourier expansion, the method of predicting cogging torque is proposed. Two-dimensional finite element model of in-wheel motor is established by Maxwell software, and electromagnetic character of that is analyzed. Skew slot, pole arc coefficient and width of slot mouth are analyzed and studied by finite element method, in order to realize the change regularity of cogging torque. Cogging torque curves under the different skew slots, the different pole arc coefficients and the different widths of slot mouth are obtained, which can effectively reduce the cogging torque of in-wheel motor, but they still exists some limitations. The final simulation analysis results are in good agreement with the theoretical predicting results, which indicates that this method can be used to afford a theoretical basis to reduce the cogging torque and optimize the in-wheel motor of electric vehicle in the future.     

超声红外热像技术中预紧力对金属平板振动特性的影响

在超声红外热像检测过程中,超声脉冲激励下被测对象的振动状态直接决定了缺陷区域的生热效果,而工具杆与被测对象之间的预紧力是影响被测对象振动状态的重要因素之一。试验结果表明:预紧力的增大使得振动能量呈上升趋势并伴随着小范围不稳定,同时被测对象的振动频谱由混沌振动开始,经历次谐波、准次谐波后达到超谐波振动状态。针对上述现象,采用显式动力学方法建立了与试验条件相对应的有限元模型,并进行了瞬态动力学分析。模型采用压电-力类比方法来模拟压电陶瓷的逆压电效应,同时引入了动态松弛来更准确模拟试验工况。仿真结果验证了试验观察到的现象,并进一步揭示了预紧力的增大将改变超声工具杆和被测平板之间的接触力状态,从而改变被测试件的振动能量分布和振动频谱。研究成果有助于实现通过预紧力来控制被测对象振动状态,进而达到优化超声红外热像检测的目的。     

旋转行波超声电机的冲击动力学模拟及实验

研究了冲击产生的高过载对旋转型行波超声电机结构和性能的影响机理和规律。首先,结合旋转型行波超声电机的工作机理和结构形式,建立了该型超声电机在冲击载荷下的有限元模型,利用显式算法模拟其在冲击过载环境中的暂态过程,分析电机的定、转子及压电元件等部件的应力和应变分布规律,研究和评估了目前超声电机结构对瞬时超大过载的耐受情况;其次,设计了特定夹持装置,对旋转型行波超声电机的耐过载特性进行了马歇特锤击实验,实验结果很好地印证了理论分析结果;最后,综合理论和实验结果评定了当前典型的旋转行波超声电机结构在特殊使用环境中的耐过载能力及易损伤部件。实验结果表明,紧凑和简单的结构特点使得超声电机本身具有较好的适应大过载环境的工作能力,在直接承8千个重力加速度冲击过载后仍能维持一定的输出特性。