大位移压电陶瓷驱动器的设计与试验

针对大位移压电陶瓷驱动器,研究了压电陶瓷双晶片的驱动效能。基于压电陶瓷材料的逆压电效应,应用压电陶瓷双晶片在机械自由、电学短路状态下,一片加正向电压缩短另一片加反向电压伸长共同作用产生弯曲变形,通过组合设计将压电陶瓷双晶片的弯曲变形位移叠加起来,实现了压电陶瓷驱动器的大位移输出。在相同电压的条件下,此压电陶瓷驱动器的输出位移量比叠层驱动器有较大的增加,达200μm,结构尺寸也大大减小。该驱动器不需要位移放大机构,可直接应用于有大位移要求的机构驱动。     

基于电流控制的压电陶瓷驱动器

为了解决电压控制型压电陶瓷驱动器驱动压电陶瓷时存在的迟滞、蠕变和带宽窄的问题,设计了基于电流控制的压电陶瓷驱动器,利用压电陶瓷致动器位移与其所带电荷量间的线性关系,该驱动器通过控制压电陶瓷的充电电流和时间控制其位移量．在此基础上,提出了以分辨率换取稳定性的动态保持控制方法,采用该电流型驱动器,实现了开环下对压电陶瓷致动器的稳定、快速、高精度定位．实验结果表明,该驱动器驱动行程为10μm的压电陶瓷时,满行程带宽大于1．5kHz,重复定位精度小于4nm（0．4％）．     

新型压电陶瓷驱动器的特性分析

讨论了一种基于压电陶瓷的新型叠堆驱动器,并阐述了其工作原理,推导出该驱动器的力学性能公式。基于压电陶瓷材料的机电耦合特性,运用ANSYS有限元软件对此驱动器进行了数值分析,研究了其驱动性能,分析结果表明,其输出位移和输出力均与输入电压呈线性关系,在较低电压下可获得较大变形量,且具有良好的动态响应特性。该叠堆压电驱动器结构简单、尺寸小、成本低,通过输入电压即可实现位移控制,可作为较好的自适应控制驱动器应用于智能摩擦阻尼器的驱动装置。     

直线超声电机驱动的精密运动平台位移分辨率

由于纳米级精度运动平台在电子隧道扫描显微镜、光刻机及精密医疗设备有广泛需求,传统驱动方式中大行程、高精度难以同时实现,而直线超声电机直接驱动的精密运动平台可望解决该问题。研究所建大行程直线超声电机系统位移分辨率影响因素,通过死区时间理论及启停实验曲线分析探索运动平台可能达到的最小步距;借助XL-80激光干涉仪,实验研究驱动波形、预压力及驱动电压对平台步距影响。结果显示,运动平台分辨率可达25 nm。     

基于槽钹形压电复合驱动的仿尺蠖式微型管道机器人

设计了一种基于槽钹形压电复合驱动的仿尺蠖爬行式微型管道机器人。该机器人包括两个Ф8n硼槽钹形压电复合驱动器和一个爬行定位系统,能够在Ф10mm的曲线形管道中自主定位爬行。槽钹形压电复合驱动器驱动能力为自重的4倍,最大爬行速度为41mm／s;爬行定位系统提供了机器人爬行步距的测量,通过实验验证整个爬行系统的定位误差仅为4‰。     

旋转尺蠖压电电机钳位机构设计及动力学分析

提出旋转尺蠖压电电机,该电机具有结构简单、定位精度高、输出力矩大、能实现微动压电电机大行程等优点。分析其驱动原理及关键部件钳位机构设计方案;考虑杠杆位移放大梁及长柔梁弯曲、扭转振动变形,建立钳位机构动力学模型,获得前8阶固有频率及模态函数;讨论钳位机构结构参数对固有频率影响规律,并实验验证理论分析的正确性。     

THUNDER元件热机电耦合动力学分析

针对THUNDER型压电驱动器这一类特殊结构形式,提出一种包含4个位移节点,8个温度节点和2个电势节点的热机电耦合混合有限元模型,并基于虚功原理推导了热机电耦合有限元方程。针对物理属性截然不同的冷却阶段、再极化阶段和驱动阶段开展了动力学研究,并利用初始位移这一变量将它们有机地联结起来;系统地分析了该类驱动器的热机电耦合问题。数值算例表明:该混合有限元模型具有良好的计算精度;THUNDER型压电驱动器的驱动性能与其制造过程密切相关,且其驱动位移与外载荷的凹曲线关系使其具有良好的综合驱动性能;在实际应用中,当温度发生变化时,热应变对驱动性能具有重大影响,而焦电效应的影响相对较小但仍十分明显,体现出对THUNDER型压电驱动器开展热机电耦合动力学研究的重要性。     

摩擦系数变化式压电叠堆惯性直线驱动器

以压电叠堆和质量块组成的压电叠堆振子为动力元件,通过利用驱动器向左运动和向右运动时接触足与接触面摩擦系数的不同,设计并制作完成了一套摩擦系数变化式压电叠堆惯性直线驱动器．分析了该驱动器的工作原理并对驱动器的运动情况作了详细分析．搭建了专用测试系统,并采用该系统对摩擦系数变化式压电叠堆惯性直线驱动器进行了性能测试．试验结果表明：当频率为10Hz时,该试验装置最小稳定步长为0．19μm,最大移动速度为11．82μm／s,最大承载能力不低于900g．     

压电陶瓷驱动器菱形位移放大机构的动态应变测量

为监测压电陶瓷驱动器并联驱动时各自的动态输出状态,利用压电陶瓷驱动器中位移放大机构的菱形对称结构建立全桥应变测量方法,通过位移放大机构菱边在振动过程中的动态应变变化来反映压电陶瓷驱动器的工作状态。对不同状态下位移放大机构菱边的动态应变进行实验研究,结果表明:利用位移放大机构对称菱边建立的全桥应变测量方法能够有效获取位移放大机构在振动过程中的动态应变变化,且能够对位移放大机构的运行状态进行实时监测,在带负载和不带负载情况下,设计的位移放大机构菱边在振动过程中的应变量级都在几个微应变,该测量结果也反映出设计的位移放大机构刚度较好,能够保证压电陶瓷驱动器有较好的输出性能。     

电液伺服阀用压电弯曲元件特性的实验研究

研制了一种压电弯曲元件型压电驱动器,该驱动器用于电液伺服阀的电-机械转换器.压电驱动器由三层结构构建,其中中间弹性层为铍青铜,在铍青铜的上下表面各粘接一片压电晶片,材料为PZT-5H.利用激光测微仪LC-2400A及LV-1610对压电驱动器的输出位移、位移滞环及谐振频率进行了实验测量,分析了压电驱动器尺寸与其特性之间的关系.实验结果表明,该驱动器满足所设计电液伺服阀的性能要求.     

The Simulation of Diaphragm Deflection Actuated by Shear Mode Piezoelectric Actuator in Microdroplet Ejector

A shear mode piezoelectric actuator is applied to deflect the diaphragm of pressure chamber in the droplet ejector or inkjet printhead. The deflection of the bulge-diaphragm and resulting swept volume is analyzed by analytical and numerical method. With free-body treatment of the model, the analytical exact solutions for the two free bodies of bulge-diaphragm and piezoelectric beam were obtained. Also, the numerical solution by ANSYS is obtained to verify the analytical result. Besides, the whole-model solution coupling the bulge-diaphragm and piezoelectric beam together was obtained by ANSYS to compare with the result of free-body analysis. In order to estimate the maximum actuating force and deflection of the shear mode piezoelectric actuator, the diaphragm characteristic curve is obtained in the free-body analysis, which presents the decreasing tendency of the central deflection with the increase of anti-deflection (or reaction) force under certain actuating voltage. Also, the diaphragm characteristic curve is obtained showing the central deflection in proportion to the action force. By combining both kinds of curves, the actuated central deflection of the bulge-diaphragm can be obtained under certain actuating voltage. Finally, both linear relations including diaphragm central deflection in proportion to actuating voltage and volume displacement in proportion to diaphragm central deflection are obtained.     

新型箝位式压电电机的设计研究

针对传统箝位式压电电机在谐振态下工作时,方波振动的箝位部分结构设计复杂问题,提出一种新型箝位式压电电机。该电机箝位部分与驱动部分均由同频正弦电压驱动实现正弦振动,通过定子对动子的箝位接触,实现动子单向输出运动。相较于传统箝位式压电电机和超声电机,该电机的定子结构设计无需采用模态简并,结构设计难度降低。利用有限元仿真确定定、动子结构参数,制造样机并搭建实验平台。对箝位部分分别采用正弦波与方波做激励,再对驱动部分进行波形对比,表明正弦波亦能达到预期效果。实验结果表明:准静态时,激励电压频率为250Hz、电压峰峰值Vp-p为10V时,步进距离为0.5μm,步进速度0.13mm/s;谐振态时,激励电压频率为540Hz、电压峰峰值Vp-p为70V时,步进距离为32μm,步进速度16.9mm/s;该电机可兼顾低频高分辨率和高频高速输出以实现跨尺度工作。     

Vibration control of a simply supported cylindrical shell using a laminated piezoelectric actuator

Summary This paper develops a novel laminated piezoelectric actuator (LPA) to control the vibration of a cylindrical shell structure, which is fabricated through bonding multiple piezoelectric layers of the same property together. The electromechanically coupled equations of the system are derived based on the classic shell theory. A parametric study is then conducted to evaluate the effects of geometric and physical properties of the actuator on actuating forces. The results show that as the number of layers increases, the actuating forces per voltage produced by LPA in the axial, circumferential and radial directions of the shell all increase noticeably. The active vibration control of a simply supported cylindrical shell using LPA of different layer numbers is simulated as well under a velocity feedback scheme. It is indicated that with the same control voltage the LPA can obtain a better control performance than the conventional single layer piezoelectric actuator as expected and the targeted radial modal vibration of the shell is attenuated significantly.     

Experimental investigation on the piezo-composite actuator with piezoelectric single-crystal layer

Studies on muscle mimicking actuators have increased in the last two decades due to the possibility of various applications for compact lightweight actuators including small unmanned aircrafts, missile, and biomimetic robots. Piezoelectric materials have been used in a variety of applications ranging from shape control of structure and active vibration control of structure to noise suppression due to compact size and good frequency response. Conventional polycrystal piezoelectric ceramic materials, however, have limited actuating strains and displacement, hindering their use in actuators for small aerospace vehicles. In this study, the design and fabrication method of an actuator with a piezoelectric single-crystal layer were investigated to increase the actuation strain and displacement. From a comparison of the performance of the LIPCA-C2 and LIPCA-S prototypes, it was found that the new LIPCA-S2, which has much higher coefficient of the unimorph actuator, can generate an actuating displacement more than twice that of LIPCA-C2.     

PZT系多层片式压电陶瓷微驱动器位移性能研究

采用陶瓷坯膜流延成型和陶瓷坯膜／金属内电极共烧技术,制作了多层片式高含铅PZT软性压电陶瓷微驱动器．该器件具有体积小、工作电压低、位移量大（38V,1.05μm）的特点．本文对制作的多层片式器件在直流和单向交流工作电压的作用下产生的静态和动态位移特性,从PZT压电陶瓷材料的晶体和电畴结构特点进行了分析和研究．     

Study of Piezoelectrically Actuated Micropumps with Multiple Parallel Chambers

This study investigated the performance of the piezoelectrically actuated parallel micropumps. The displacement of the piezoelectric (PZT) actuator and the flow rate of the micropump were studied in terms of operating parameters. Using a nonlinear regression technique, empirical models of the micropumps were established based on the experimental data. The experimental results indicated that the displacement of the piezoelectric actuator increased with actuating voltage but decreased with frequency. The flow rate of the micropump was proportional to the applied voltage and demonstrated that the maximum flow rate occurred at an adequate frequency. When operated at a voltage of 140 V and a frequency of 20 Hz, the single micropump delivered a maximum flow rate of 91 µ 1/min. At the same input signal, the maximum flow rate of the double parallel micropump was 1.5 times that of the single micropump, and approximately twice that of the single micropump for triple parallel operation. Furthermore, the obtained non-linear regression formulae can be utilized to predict the flow rate of the micropump with multiparallel chambers.     

一次逆、二次正压电效应在自感知执行器上的应用

提出利用一次逆、二次正压电效应为同一压电体内的双向效应原理,进行传感器与执行器集成一体化——自感知执行器的研究.即利用一次逆压电效应输出一个微位移,作为执行器使用;利用二次正压电效应的输出电荷自感知执行器的输出位移,作为传感器使用.在准静态（电压0～50V）和低频（电压100V,频率10Hz）条件下,分别进行了一次逆压电效应输出位移、二次正压电效应输出电压的实验,并将得到的数据进行归一化处理.实验结果表明,通过测量二次正压电效应产生的电荷能够较好地自感知一次逆压电效应产生的位移.     

三角混合两级杠杆微位移放大机构的设计及性能分析

针对压电执行器和压电驱动平台输出行程有限的问题,设计了一种三角混合两级杠杆微位移放大机构。首先,理论推导了该微位移放大机构的位移放大公式,得到了位移放大比;其次,分析了不同类型两级杠杆结构支点铰链对施加载荷的敏感性;最后,利用ANSYS软件对机构进行静力学和动力学仿真,对机构的相对寄生运动比和固有频率进行了分析。结果表明：当选取直梁形铰链作为两级杠杆结构的支点铰链时,机构对施加载荷的敏感性较强;机构位移放大比理论值与仿真值的相对误差为9.56%,相对寄生运动比为0.348 2,且1阶固有频率最佳。所设计的微位移放大机构具有较小的寄生位移、较强的抗干扰能力和较好的动力学性能。研究结果为压电驱动器或快速反射镜支撑结构实现大量程的位移输出提供了一定的理论指导。     

空分复用压电自感知执行器执行与传感效果研究

结构振动主动控制可以采用压电自感知执行器。空分复用解耦方法是实现压电自感知执行器的一种新方法，实质是采用几何方法解耦，即将压电片的一个完整电极分割为执行区和传感区以实现自感知。本文以悬臂梁为对象，以涡流位移计作为标准传感器，对两种电极分割方式的压电片的传感和执行效果进行了实验研究。通过测量压电梁的频率特性，证明了空分复用的压电陶瓷片同时兼有传感和执行两种功能。实验结果也表明传感区的敏感输出受到执行区激励电压的静电耦合的影响，利用悬臂梁存在反谐振点的特性，提出了一种定量测量静电耦合的方法，并测定了不同电极宽度、不同极间隙下的静电耦合系数。本文的工作为采用空分复用的压电自感知执行器进行振动主动控制奠定了基础。     

Deflection characteristics of a trapezoidal multilayer in-plane bending piezoelectric actuator

A novel multilayer split-morph actuator has been designed and fabricated using the thick film screen-printing technology. Deflection characteristics of the split-morph actuator have been investigated by theoretical analysis and experimental measurement. The results indicate that the tip displacement is inversely proportional to the thickness of each piezoelectric layer, but is independent of the number of layers and the total thickness of the actuator. The displacement/voltage sensitivity of the trapezoidal actuator is larger than that of the rectangular design, assuming both have the same width of clamped end and the same thickness of the piezoelectric layers. The maximum displacement/voltage sensitivity of 0.157 micron/V was obtained with a split-morph actuator with 30-micron thick layers. The proposed actuator is a promising candidate for the secondary fine-tuning actuator of a dual stage head-positioning servo system in high density hard disk drives.