基于压电微激励器的硬盘双程伺服控制系统

介绍了硬盘双程伺服控制系统,其在常规的音圈电机基础上引入一个压电微激励器来实现更快速和精确的磁头定位。控制设计中,利用压电微激励器的频率特性来估计它的位移输出;音圈电机的控制采用一种积分增强的组合非线性反馈(CNF)控制技术,实现快速和平稳的设定点跟踪,消除扰动因素可能造成的静态误差;基于开环逆控制的思想,微激励器环路的控制采用定值比例及滤波器,使其紧密跟踪定位误差,从而使总位移输出能更快地跟踪设定目标值。仿真和实验结果验证了设计的有效性。     

AC-Poling of Functionally Graded Piezoelectric Bending Devices

Monolithic ceramics with an uniaxial gradient of piezoelectric and/or dielectric coefficients (functionally graded materials—FGM) are suitable for bending actuators with strongly reduced internal mechanical stresses.

We prepared BaTi_1—xSn_xO₃ ceramics with a Sn-content of 7.5 mol% (BTS7.5) at the upper side and 15 mol% (BTS15) at the lower side. Two sheets of powder with different stoichiometry were pressed and sintered. The gradient of stoichiometry was modified by additional layers of powder with 10 and 12.5 mol% Sn, respectively. The Sn content after sintering across the thickness was investigated by Electron Probe Micro-Analysis (EPMA).

The gradient of the chemical composition was transformed into a functionally gradient of the electromechanical properties by a poling process. An increasing of the bending deflection was obtained by cycling with an unipolar AC-voltage. In this work we studied two effects which can explain this behavior.     

压电材料与器件在电气工程领域的应用

随着能源革命的不断深入和能源互联网的持续建设,对电网自动化、智能化、信息化的需求日益迫切,亟需先进的电力设备传感量测方法为电网多场景应用提供信息支撑,以保证智能电网在复杂工况下的安全可靠运行.压电材料作为感知电力设备放电、振动等信号的关键材料,在电力设备振动监测、放电检测、探伤、温度测量、电压传感等领域得到广泛应用.该...     

面向电力设备检测与诊断的压电材料及器件

随着中国智能电网建设不断推进及电网规模的扩大,以压电材料为核心的传感器和能量采集器在电力系统在线监测、故障检修、无线传感器网络等方面扮演着越来越重要的角色。从电力检测和传感器自取能出发,回顾近年来基于压电效应的电压电场传感器、声检测和环境能量采集装置的研究进展并介绍了压电陶瓷、压电驻极体、压电复合材料等传统和新兴的压电材料。在现有研究基础上,指出在智能电力系统建设中各类压电器件所面临的挑战,包括频率匹配、环境适应性和集成化等,需要新的微纳加工技术、探索压电效应与其他物理效应耦合、设计新型压电材料和能量收集电路来助力新型压电器件的实际应用。     

压电器件减振控制技术的发展和研究现状概述

作为一种新兴的智能材料,压电材料在振动控制领域的应用越来越广。归纳了压电材料用于减振控制的主动控制、半主动控制、被动控制及混合振动控制等四种方法原理、优缺点及国内外主要研究成果;并介绍了针对各方法的不足所提出的扩展研究,如自感知主动控制、基于压电分流阻尼的声子晶体技术以及基于开关半主动控制的自供电技术等,借此可为磁致伸缩材料等其他智能材料在减振控制方面提供借鉴和新的设计思路。     

Piezoelectric polymers

Polymers with piezoelectric and pyroelectric properties that make them useful for biomedical applications and devices are considered. The characteristics of such polymers are examined, and transducers made from them are discussed. Laboratory developments of devices using piezoelectric polymers are briefly reviewed, and the slowness of product development in this area is commented on.     

Piezoelectric actuators 2006

Piezoelectric actuators have been commercialized in various areas such as information technology, robotics, bio-, medical engineering, ecological and energy engineering. This paper reviews their recent application developments and foresees the future of piezoelectric actuators.     

Piezoelectric polymer electrets

In this review the physical properties, mechanisms and models are reviewed which explain the high piezoelectricity of the ferroelectric polymers of the polyvinylidene fluoride (PVDF) family, the odd nylons, the vinylidene cyanide (VDCN) copolymers and polyurea. Because PVDF and its copolymers with trifluoroethylene (TrFE) and tetrafluoroethylene (TFE) have been studied extensively in the last 25 years the main part of the review deals with these polymers. Additionally a short summary of the different piezoelectric applications of PVDF is presented. The odd nylons, the VDCN copolymers and the polyurea are compared with PVDF to show the different stabilization mechanisms of the remanent polarization and the different temperature behavior of the piezoelectricity. This review not only concentrates on the work done in the last few years but in order to describe the behavior of these polymers in detail, it is necessary to go back to the roots. Therefore many articles from the late seventies and early eighties are included     

Micro Piezoelectric Ultrasonic Motors

This paper reviews recent developments of micro ultrasonic rotary motors using piezoelectric resonant vibrations. Following the historical background, four ultrasonic motors recently developed at Penn State University are introduced; windmill, PZT tube, metal tube, and shear-type motors. Driving principles and motor characteristics are described in comparison with the conventional ultrasonic motors. Motors with 1.5 mm in diameter and 0.8 mNm in torque have been actually developed.     

宽温系列温敏铁氧体及其应用器件

本文分析了国内外对温敏铁氧体及应用器件的开发背景,从宽温系列温敏铁氧体材及器件的应用需求着手,提出温敏铁氧体材料温度范围拓展的方向,优化了现有温敏磁控开关的结构用以实现-80℃~+280℃宽温系列温敏铁氧体器件的开发和应用,有助于标准化的简化和统一原则。     

Microfabrication of Piezoelectric MEMS

In this paper we present an overview of processes for fabrication of piezoelectric thin film devices using PZT (Pb(Zr _x Ti_{1 ? x} )O₃) in planar structures. These structures are used in cantilever-like and membrane configurations for sensing and actuation. Elaboration of a compatible wet and dry etching sequence for patterning of PZT, electrodes, SiO₂ and silicon substrate is the key issues. The method for compensation of mechanical stresses to obtain flat, multilayer structures is demonstrated. Definition of membrane thickness and release of the structures are obtained by Deep Reactive Ion Etching of silicon (SOI—silicon on insulator substrates) or by surface micromachining. The complete process has been used for fabrication of cantilever arrays, ultrasonic transducers and pressure sensors. Excellent permittivity and transverse piezoelectric coefficient of PZT have been obtained with the final devices. Other examples of applications like: ferroelectric memories, nanopatterning and local growth of PZT are presented as well. The microfabrication of piezoelectric MEMS was found to be a complex task where all aspects from device design, material properties and microfabrication to assessment of performance are closely interconnected.     

压电微电机之综述

利用压电薄膜的低温沉积工艺与微机械加工技术结合可以制作出压电微电机。这种压电微电机在医用微型器械,自聚焦系统,精密微定位、微型机器人等领域有着重要应用。本文介绍了几种压电微电机的制作过程、结构、工作原理及有关结果,并指出了目前存在的问题和下一步研究发展的方向。     

Lead Free Piezoelectric Materials

Lead oxide based ferroelectrics, represented by lead zirconate titanate (Pb(Zr, Ti)O₃) or PZT) are the most widely used materials for piezoelectric actuators, sensors and transducers due to their excellent piezoelectric properties. Considering lead toxicity, there is interest in developing piezoelectric materials that are biocompatible and environmentally friendlier. The low density of non-lead based materials can also be an advantage in transducers for underwater and medical imaging due to expected lower acoustical impedance. Another impetus for seeking alternative to lead based compositions is the need for piezoelectric materials for operation at high temperatures. Several classes of materials are now being reconsidered as potentially attractive alternatives to PZT for special applications. The potassium niobate family, KNbO₃, exhibits low dielectric constants, large thickness coupling coefficient along certain non-polar directions, and low density, all of which have advantages for high frequency transducer applications. Several compositions belonging to bismuth titanate family, Bi₄Ti₃O₁₂, such as SrTi₄Bi₄O₁₅, are promising candidates for high temperature applications. Lead free materials alone (eg. (Na_0.5Bi_0.5)TiO₃) or in solution with PT (BiScO₃ – PbTiO₃) are also potentially interesting as they combine high piezoelectric activity and, in some cases, relatively high T_c. For these families of piezoelectric materials, the processing and piezoelectric response under different conditions of pressure, frequency, and temperature are presently much less understood than for the classical lead containing systems. In this presentation we review and discuss piezoelectric properties of selected lead free compositions (principally for members of the potassium niobate family and bismuth titanate layered compounds) in relation to structural and microstructural features as well as extrinsic contributions (domain walls displacement, conductivity) to their electromechanical properties. It is shown that it is possible to obtain remarkably stable piezoelectric response in some compositions, while others exhibit strong dependence of piezoelectric properties on driving field and frequency. Origins of these different behaviours are discussed.     

基于压电陶瓷逆压电效应的电压信号变送原理

提出了一种采用压电陶瓷材料和反射式光纤位移传感器的新型电压信号变送原理,利用压电陶瓷材料的逆压电效应获得被测电压动态位移,再由反射式光纤位移传感器测量逆压电效应所产生的动态位移量,实现电压参量的测量.通过对其线性度、准确度和温度特性的测试,结果表明,基于新型变送原理的电压互感器在实验室环境下的测量准确度可以达到0.1级,温度特性稳定.     

Miniature Contactless Piezoelectric Wind Turbine

This study presents the development of a miniature wind turbine that can be used for powering wireless sensors deployed at remote locations. The wind turbine utilizes piezoelectric transducers in order to reduce the start-up speed. Six piezoelectric bimorphs with magnetic tip mass were actuated through attractive and repulsive force between permanent magnets. The design and characterization of the prototype is discussed along with a Finite Element Model (FEM) of the piezoelectric elements. The wind turbine was 23 cm high and 16.5 cm wide. It was able to achieve low cut-in speeds of 1m/s providing power outputs ranging between 0.5 mW and 3 mW for wind speeds in the range of 1 m/s to 4 m/s.     

可互换虚拟设备技术

本文介绍了实现自动测试系统设备可互换性的新方法可互换虚拟设备技术。     

电力电子器件

电力电子技术包括电力电子器件和由这些器件组成的各种变换电路及装置两个方面,其中电力电子器件是基础,它对装置的尺寸、重量、技术性能和价格有着极大的影响。每种新器件的出现,都将引起相关技术的重大变革。可以说,一代器件决定一代整机。     

Design of a Triaxial Piezoelectric Accelerometer

A monolithic MEMS triaxial accelerometer based on piezoelectric lead zirconate titanate (PZT) thin films with highly symmetric quad-beams and a seismic mass, has been designed and simulated. Theoretical and numerical models for this structure are presented. The dynamic response and the trade-off between several design considerations are discussed. Static and modal simulations with FEM (Finite Element Method) simulator have been performed to analyze the mechanical response. It shows that the sensitivities of the three axes (X, Y, Z) are respectively 27, 27, and 29 mv/g, and there is almost no transverse sensitivity for the accelerometer. Also, the device is expected to have good temperature performance.