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1.
Autonomous Microrobots   总被引:5,自引:0,他引:5  
Robots have been a subject of research for almost half a century. In order to make robots more versatile they must be able to operate in a semi-structured work place where unforeseen events occur and where sensor data are incomplete. An entire research community has been working on this problem and many unique autonomous and so-called intelligent robots have been conceived and built. Most of these efforts are concerned with robots that operate in the macroworld where they take on chores that could also be handled by humans. However, there is the mocroworld in which manipulation and handling tasks are very difficult and for which a human has no tools and where the work area is so small that fine manual manipulation is almost impossible. This paper is concerned with autonomous robots that can operate in a microworld, where microassembly operations, microsurgery or integrated circuit testing and repair is done. For independent operations, these robots need special sensors and an efficient computer architecture that hosts the planner and executor. There are also special drive systems and effectors necessary for micromotions and micromanipulations, respectively. An attempt is made to describe these components and the problems encountered in configuring them to a microrobot. As an example of advanced microrobots, the design and functions of several autonomous microrobots of the University of Karlsruhe are shown; they employ different locomotion and subject handling principles. The paper also includes a discussion of the typical operating problems caused by the microworld and of future research that has to be done to conceive and build efficient microrobots.  相似文献
2.
This paper establishes and investigates an enhanced adaptive motion tracking control methodology for piezo-actuated flexure-based four-bar micro/nano manipulation mechanisms. This control methodology is proposed for tracking desired motion trajectories in the presence of unknown or uncertain system parameters, non-linearities including the hysteresis effect, and external disturbances in the motion systems. In this paper, the equations for the modelling of a flexure-hinged four-bar micro/nano mechanism are established. These include the angular stiffness, ‘static’ linear stiffness, equation of motion, and lowest structural resonance of the mechanism. In addition, a lumped parameter dynamic model that combines the piezoelectric actuator and the micro/nano mechanism is established for the formulation of the proposed control methodology. The stability of the control approach is analysed, and the convergence of the position and velocity tracking errors to zero is proven theoretically. A precise tracking performance in following a desired motion trajectory is also demonstrated in the experimental study. An important advantage of this control methodology is that the approach requires only a knowledge of the estimated lumped system parameters in the physical realisation. This proposed motion tracking control methodology is very attractive for the implementation of high performance flexure-based micro/nano manipulation control applications.  相似文献
3.
4.
Micro-scaled parts with dimension below 1 mm need to be manipulated with high precision and consistency in order to guarantee successful microassembly process. Often these requirements are difficult to be achieved particularly due to the problems associated with the structural integrity of the grasping mechanism which will affect the accuracy of the manipulation. Furthermore, the object's texture and fragility imply that small perturbation by the grasping mechanism can result in substantial damage to the object and leads to the degradation of its geometry, shape, and quality. This paper focuses on the unification of two designing approaches to develop a compliant-based microgripper for performing high precision manipulation of micro-objects. A combination of Pseudo Rigid Body Model (PRBM) and Finite Element Analysis (FEA) technique has proven to improve the design efficiency by providing the essential guideline to expedite the prototyping procedure which effectively reduces the cost and modeling time. An Electro Discharge Machining (EDM) technique was utilized for the fabrication of the device. Series of experimental studies were conducted for performance verification and the results are compared with the computational analysis results. A high displacement amplification and maximum stroke of 100 μm can be achieved.  相似文献
5.
串联压电微泵特性研究   总被引:1,自引:0,他引:1  
介绍了一种压电驱动的串联无阀微泵.基于收缩管/扩展管整流特性的分析,建立了微泵输出特性的表达公式.采用有限元仿真软件ANSYS对微泵内流体的流动过成进行了数值模拟,结果显示,在相同的驱动条件下,串联无阀微泵的工作性能优于单腔无阀微泵的工作性能.泵流量随着驱动电压的增加而增加.当固定的驱动电压下,存在最优的压电层厚度使得泵流量最大.研究结果为串联微泵的优化设计提供了依据.  相似文献
6.
压电陶瓷驱动器的建模分析与自适应逆控制   总被引:1,自引:0,他引:1  
压电陶瓷驱动器的迟滞特性可用 Prandtl- Ishlinskii启动模型 (PIOP)描述 ,基于此本文提出一种自适应逆控制方案 .对象和逆控制器分别由一个 Prandtl- Ishlinskii停止模型 (PIOS)表示 ,应用稳定的归一化修正梯度算法 ,进行权值在线更新并收敛于驱动器逆模型实际值 .以降低非线性导致的控制误差提高控制品质  相似文献
7.
本文提出了利用柔性机械臂的柔性并通过压电驱动器实施精密定位,实现微位移和微力操作的思想.为此针对二连杆柔性机械臂建立了其微位移、微力操作的解析模型,并理论和仿真分析其可达作业空间能力及其可操作性.通过应用例子仿真研究表明方法的有效性,拓宽了压电驱动器应用于柔性机械臂振动控制的思想  相似文献
8.
基于虚拟仪器的压电微位移驱动器线性化研究   总被引:1,自引:0,他引:1  
根据压电陶瓷的非线性特性,提出了一种采用离散电压标定和控制压电微位移驱动器线性化的方法。利用数模输出卡,输出不同步长的单个的离散电压,控制压电陶瓷伸长的速度,从而达到利用选取的电压值参数来控制压电陶瓷伸长速度的目的。选取恰当的电压值,可以使得压电驱动器在时间域上线性地伸长而达到线性化。设计基于Labview的控制系统,并对线性化方法进行了原理分析和实验。实验结果表明,该系统可以有效地在0—300V范围内使压电微位移驱动器的伸长量与时间成线性关系,定位精度为1nm。  相似文献
9.
Parallel printing in a microarray format is becoming increasingly important. This paper presents a 2-D multi-channel dispenser with a spotting spacing of 500 μm. The dispenser is continuously loaded from a 384-well plate format and shoots upward. New technologies using polyimide substrate was developed, and the flexibility of the polyimide sheets allows scaling the dispenser up to an array format of 24×16. Drop formation is analyzed by stroboscopic illumination and by spotting onto glass slides. Droplets of 65 pL are dispensed in parallel up to 5 kHz at a droplet speed of 2 m/s.  相似文献
10.
Theoretical designs of piezoelectric ceramic helical and spiral actuators have existed for many years. The main reason these devices have not achieved widespread recognition and use is the perceived difficulty of processing such forms. These processing problems, covering both the material form itself and electrode placement, have been tackled and solved over recent years at the University of Birmingham. A new type of complex piezoelectric spring-type actuator has arisen as a result of this work, which takes the form of a super-helix, and is known as a wound helical electrically reactive mechanism (WHERM). This actuator structure shows a great deal of versatility in terms of the device parameters, which can be tailored to suitable applications. We show here that the geometry of this actuator effectively provides for an efficient method of amplifying the small strain produced in a piezoelectric material in exchange for a proportional reduction in maximum force holding ability. Devices shown exhibit peak no-load displacements of over ±3 mm, with a force holding ability of up to 0.2 N, and with a total circular footprint of less than 45 mm in diameter.  相似文献
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