基于压电驱动技术的细胞微量注射装置

提出了用压电陶瓷在通电下产生的微小变形的原理来设计压电驱动器,利用微位移压电驱动器来完成细胞微量注射微动平台的定位和注射,并且将微动平台和由电机带动的细胞微载台来构成细胞药物微量注射的机械结构与控制系统。压电式细胞微量注射装置的定位和注射动作全部由压电驱动器来完成,和目前国内外的细胞微量注射装置相比主要特点是定位精度和注射精度都比较高。     

高压低纹波纳米驱动器

针对压电陶瓷进行了纳米级驱动技术的研究,优化了传统的直流放大式驱动技术的系统特性。深度分析了以压电陶瓷为驱动元件的纳米级微位移驱动技术的特性,实现了以下两方面的突破:在设计基于压电陶瓷元件实现纳米精度定位的研究中,设计出了数控压电陶瓷驱动器;深入研究了压电陶瓷容性元件特性后设计出电压恒流源式驱动电路,同时在电路中引入负反馈,稳定了驱动器的输出。通过大量实验证明,该设计很好地解决了压电陶瓷驱动高精度、快响应的难点,具有很高的实用价值。     

叠层型压电驱动器技术及实验研究

叠层型压电陶瓷利用逆压电效应可以得到精确的微位移量.介绍了叠层型压电驱动器的性能特性.并基于正交三角放大原理设计了一种微位移放大机构,使其将叠层型压电微位移器的位移量放大.实验结果表明,驱动器各项指标均达到设计要求,证明了设计理论的正确性.     

尺蠖式压电陶瓷驱动电源设计

为了满足尺蠖式压电陶瓷驱动器的控制需要,设计了相应的驱动电源。DSP是控制器,通过网口接收上位机的控制命令,通过异步总线与FPGA进行数据通信,FPGA操作4路D/A生成4路满足相应时序要求的波形,波形经过精密运放前级放大和由分立元器件搭建的功率放大,输出到尺蠖式压电陶瓷驱动器的电源输入端。测试和试验表明,电源带宽高,纹波小,阶跃响应特性和动态特性良好,能够精确的控制尺蠖式压电陶瓷驱动器微位移定位,可以应用在精密工程技术领域中。     

基于机器视觉的宏/微双驱动与控制系统的研究

针对目前单一的驱动方式日益不能满足越来越多的微操作的要求,提出了利用步进电动机和压电驱动器组成宏/微双驱动的微操作平台.步进电动机实现大行程移动和定位,压电驱动器进行高精度定位误差补偿.同时为了解决宏/微双驱动两部分的协调控制问题,提出了利用全局机器视觉的协调控制方法,将末端执行器与目标点的距离作为控制阈值;如果当前距离大于设定的控制阈值,则起动宏动台进行驱动定位;否则起动压电驱动器进行定位误差补偿.试验结果表明:系统的定位速度快,定位精度为1 μm,稳定定位时间小于40 ms.     

压电陶瓷驱动器动态驱动电源设计

针对大位移压电陶瓷驱动器的特点,设计了一种可动态应用的驱动电源,并给出了详细的电路原理图.对驱动电源的性能试验表明,在输入为正弦波、三角波和方波等动态信号时,该驱动电源可以很好的跟随输入信号的变化,显示出优异的动态性能.对压电陶瓷驱动器的驱动试验表明,该驱动电源具有较强的带负载能力,可满足大位移压电陶瓷驱动器的动态驱动...     

压电驱动器研究与应用中的若干新进展

作为新型功能材料驱动器家族中的重要成员,压电陶瓷在工业生产和日常生活中得到了广泛的应用。由压电陶瓷构成的精度高、控制方便、能耗低的驱动器,在精密伺服控制系统中具有独特的技术优势。详细阐明了压电驱动器的独特优点,概述了其结构类型与应用分类。在此基础上,综述了该驱动器研究与应用中的若干热点以及未来的发展趋势。     

弯振复合型螺杆式压电驱动器研究

为了提高压电驱动器的机械输出性能,便于压电驱动器振动能量的传输,研制了一种弯振复合型螺杆式压电驱动器。该驱动器由圆筒和两个弯振夹心式换能器组成,换能器由变幅杆和两组弯振压电陶瓷片组成,且变幅杆和圆筒采用一体结构。对驱动器的工作原理进行了分析,利用有限元法对换能器进行了仿真,实现了换能器两个振动模态特征频率的匹配。对驱动器的基本输出特性进行了测试,测试结果表明该驱动器的螺杆最大输出速度为0.62mm/s,最大输出力为1.8 N。     

关于新型功能材料精密微驱动器的研究综述

精密微驱动器是微机电系统的核心部件,是实现微器件运动的关键。微驱动器的工作原理主要是利用物体的物性效应(物理效应、化学效应、生物效应等)实现对目的物的驱动与操作,本质就是将光、电、热等多种形式的能量转换成为机械能输出,是近几年研究的热点。文章全面综述了电热式、磁致伸缩、电磁、压电陶瓷、静电和形状记忆合金几种微位移驱动器的原理、结构、特性及应用领域。     

新型压电驱动机电耦合动力学系统分析与建模

为了准确描述压电陶瓷驱动器中存在的复杂非线性滞回动力学特性,采用分层建模原理,建立了驱动器中底层压电叠堆的非线性滞回子模型。将该底层子模型与驱动器中上层弹性和运动部件的子模型进行集成,导出了一种具有仿射形式的新型机电耦合非线性集总参数ECNLP模型。通过时域的仿真与实验对比验证和频域的动力学分析表明,该模型不仅能够准确、合理的刻画压电叠堆中的非线性滞回动、静态特性,而且充分考虑了驱动器中弹性和运动部件的动力学特性,为以后压电陶瓷驱动器控制系统的设计提供了一种新的建模方法。     

双重驱动双连杆柔性臂系统建模与抑振仿真

以宏微双重驱动的双连杆柔性臂机器人为背景，研究其建模与振动控制问题。通过忽略弹性振动对刚性运动的影响，用拉格朗日方程建立了对刚性运动模型，建立了由伺服电机和压电陶瓷共同作用下的振动方程，然后在刚性模型基础上叠加振动模型实现了对柔性臂的描述；这种模型的优点是系统总的模型简单且易于同时考虑多个振动模态。最后给出了压电陶瓷抑振过程的计算机仿真结果。     

运放对压电陶瓷驱动电路系统精度影响的研究

为了在光刻机投影物镜中使用压电陶瓷对像质补偿镜组进行精密定位,设计了一种以集成运算放大器构成的压电陶瓷驱动电路。针对光刻物镜中压电陶瓷的亚微米量级高精度定位要求,研究了驱动电路的系统精度要求,并对系统误差进行分解,着重分析了运算放大器放对系统精度的影响。首先,分析运放失调误差的影响;其次,使用PSpice仿真获得运放的固有频率特性,分析工作带宽下运放有限开环增益的影响;然后,对运放反馈网络的影响进行分析;最后,分析运放输出噪声的影响。计算表明,在最坏情况下该压电陶瓷驱动电路中由运算放大器引起的系统误差小于130mV,满足系统误差分配的要求。试制了系统样机并进行了验证实验,实验结果表明由运放引起的系统误差不超过100mV,与理论分析的结果符合。     

An Overview of Rapidly Prototyped Piezoelectric Actuators and Grain-Oriented Ceramics

Rapid prototyping (RP) has been used to fabricate a series of piezoelectric actuators, including spiral and tube actuators, to study the actuation mechanism in these geometries, and to obtain enhanced properties. PZT spiral actuators showed large displacement in mm range, and moderate blocking force. Unimorph spirals (PZT/metal shim) and dual-material (piezoelectric/electrostrictive) PMN-PT spirals were also prototyped and characterized. Tube actuators with inward and outward wall curvature showed slight improvement in axial and radial displacements compared to conventional straight-walled tube actuators. In order to improve the performance of ceramic actuators with polycrystalline microstructures, grain-oriented ceramics of bismuth titanate, lead metaniobate, and PMN-PT were investigated. Texturing was achieved by incorporating anisometric seeds into RP feedstock, aligning them during fabrication, and growing the seeds (templates) at elevated temperatures. Synthesis of anisometric seeds and pertinent processing conditions of the textured ceramics are presented. The feasibility of making net shape single crystal components was also explored. Single crystals of 0.65PMN-0.35PT were grown in FDC components using embedded (111) and (110) SrTiO₃ seeds at 1250°C.     

THIN-FILM PIEZOELECTRIC ACTUATORS FOR BIO-INSPIRED MICRO-ROBOTIC APPLICATIONS

ABSTRACT

Biologically-inspired autonomous micro-robots have a variety of anticipated applications resulting from their unique scale and cooperative potential. To achieve locomotion comparable to biological systems, these micro-robots will require actuators substantially stronger than most existing MEMS actuation technologies. Piezoelectric thin-films can meet these specifications while drawing limited power and contributing little mass to micro-robotic systems. Theoretical actuation requirements for micro-robotic applications show that lead-zirconium-titanate (PZT) thin-film actuators can meet these requirements, including a new thin-film PZT lateral actuator developed by the United States Army Research Laboratory. Experimental results and a comparison to other common lateral actuation technologies are presented.     

Poling Conditions of Pre-Stressed Piezoelectric Actuators and Their Displacement

The poling procedure has always been the key issue in producing piezoelectric actuators with optimised performance. This is also true with the relatively new category of pre-stressed bender actuators, where mechanical bias achieved with a passive layer is introduced in the actuators during manufacturing. Due to these factors, the behaviour of the actuator under poling is different compared to its bulk counterparts. In this paper, two different thicknesses of commercial PZT 5A and PZT 5H materials were used in bulk actuators and pre-stressed benders realised by new method. Pre-stress was introduced by using a post-fired biasing layer utilising sintering shrinkage and difference in thermal expansion. The hysteresis loop of the actuators was measured under 0.5–7.0 MV/m electric fields at 25–125^∘C temperatures, providing information about their remnant polarisation and coercive field before poling. The results showed that high electric field and 25^∘C temperatures in poling provided higher remnant polarisation and coercive electric field than using 125^∘C temperature at poling. Difference was especially significant in coercive electric field values where up to 114.8% difference was obtained for PZT 5H bulk actuator and 65.9% for pre-stressed actuators. Higher coercive fields can be utilized as increased operating voltage range of piezoelectric devices. The differences in results obtained here and by others can be explained by the different pre-stress level, stronger clamping of the thicker passive layers of the RAINBOW and THUNDER actuators and passive ring area introducing high tensile stresses. The same conditions were used to pole the actuators, after which the displacement and dielectric constant of the actuators were measured. The displacement measurements showed that remnant polarisation has good correlation with displacement. This fact can be used in estimating pre-stressed actuator performance before actual poling. The dielectric constant measurements with a small signal after poling gave even better correlation than the remnant polarisation.     

微执行器驱动机理研究

微电子机械系统(MEMS)技术在未来的发展有着重要的意义，文章介绍了MEMS微致动器和各类驱动模式的优缺点，并以微电动机为例，详细比较了其执行机制和原理。     

双连杆柔性臂机器人的模糊补偿滑模控制

提出了宏微双重驱动双连杆柔性臂机器人递阶控制系统结构，下层为根据柔性臂刚性模态设计的实现关节角位置控制的滑模算法和压电陶瓷抑振器，上层为根据关节角误差信号和滑模函数变化趋势建立的模糊推理表用以确定对滑模控制律的修正。借助自动机模型分析了系统的稳定性，将控制律在包含柔性模态的完整柔性臂机器人模型上进行计算机仿真，取得了满意的结果。     

Active beam vibration control using PZT actuators

Abstract

Smart materials of lead-zirconate-titanate (PZT) piezoelectric ceramics have attracted attention in recent years for active vibration control, acoustic noise suppression, health monitoring and damage assessment. We at McDonnell Douglas Aerospace have been studying these ceramics for use as sensors and actuators in various space and aircraft structures. In this paper, we will report results of a recent study on active vibration control using monomorph PZT actuators. The experiments were performed on thin aluminum cantilever beams. Collocated and non-collocated sensors and actuators were employed. Two control techniques: the classical velocity feedback and adaptive feedback controls, were investigated. We have obtained significant damping and broadband vibration attenuation of greater than 30 dB using the classical control with the single-input single-output feedback approach. A 24 dB reduction has also been achieved using the adaptive control with the multiple-input single-output approach. Detailed experimental methods and results will be described.     

High throughput experimentation for the development of new piezoelectric ceramics

Piezoelectric ceramics based on the perovskite Pb(Zr,Ti)O₃ (PZT) system are widely used as sensors and actuators. The toxicity of lead has motivated research in the field of alternative environmentally friendly lead-free materials. Lead-free piezoelectric ceramics are numerous and in comparison to PZT poorly investigated. The performance of PZT cannot yet be achieved by any lead-free material. Thus High Throughput Experimentation (HTE) shall be applied to discover new lead-free piezoelectric ceramics. In the present study a parallel solid state synthesis method was established for bulk ceramics. Libraries consisting of chemically diverse oxides are produced via the mixed-oxide route. Subsequently, classical piezoelectric parameters such as ɛ, d₃₃ and Curie temperature are screened. The high throughput route, which allows the synthesis and characterisation of over one hundred samples per week, has to be validated with PZT samples. The morphotropic phase boundary was clearly identified and dielectric measurement shows excellent results. The method may be extended to lead-free materials.     

MICRO ACOUSTIC DEVICES USING PIEZOELECTRIC FILMS

ABSTRACT

A novel PZT based micro acoustic device with the diaphragms clamped on all four edges has been studied. It can be used both as microphone and microspeaker. Compared with other piezoelectric micro acoustic devices, PZT based device has higher sensitivity for microphone and larger output acoustic pressure for microspeaker. The microfabrication process flow of this device is simple, and the transducer has excellent performance, miniature size and high reliability. The micro acoustic devices could be widely used in various practical audio frequencies and ultrasonic systems.