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滚针轴承自动装针机设计,轴承,自动,装针机,设计
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本科生毕业设计（论文）开题报告学生姓名： 学 号： 班 级： 专 业： 指导教师： 一 课题介绍：1课题名称：滚针轴承自动装针机设计2课题背景：课题来源：本课题来源于中国第一汽车集团公司（FAW）,专为CA141汽车传动轴中万向节滚针轴承的装配过程设计的自动装针机。自动滚针轴承装针机能有效解决人工装针速度慢，合格率低等问题，该机可装配各种规格的滚针轴承。机床和机床自动线：机床和机床自动线是一种专用高效自动化技术装备，目前，由于它仍是大批量机械产品实现高效、 高质量和经济性生产的关键装备，因而被广泛应用于汽车、拖拉机、内燃机和压缩机等许多工业生产领域。其中 ，特别是汽车工业，是机床和自动线最大的用户。如德国大众汽车厂在Salzgitter的发动机工厂，90年代初所采用的金属切削机床主要是自动线(60%)、组合机床(20%)和加工中心(20%)。显然，在大批量生产的机械工业部门，大量采用的设备是机床和自动线。因此，机床及其自动线的技术性能和综合自动化水平，在很大程度上决定了这些工业部门产品的生产效率、产品质量和企业生产组织的结构，也在很大程度上决定了企业产品的竞争力。使用专用自动化机床是大批量生产提高生产率降低成本的重要途径。专用自动化机床往往具有投资省，见效快等特点，因而在大批量生产中被广泛采用。自动机床或半自动机床主要用于轴类和盘套类零件的加工和装配自动化。这类机床的最大特点是可以根据生产装配需要，在更换或调整部分零部件（例如凸轮或靠模等）后可加工不同的零件，适合于大批量少品种生产装配。因此，这类机庆使用比较广泛。专用机床是按一种零件（或一组相似的零件）的一个加工工序而专门设计制造的自动化机床。专用机床的结构和部件大都是专门和单独制造的这类机床的，这类机床的设计制造往往时间较长，投资也较大，因此采用这类机床时，必须考虑以下基本原则：被加工的工件除具有大批量的特点外，还必须结构定型；工件的加工工艺必须是合理和可靠的。在大多数情况下，需要进行必要的工艺试验，保证专用机床所采用的加工工艺先进可靠，所完成的工序加工精度稳定；在机床上采用一些新的结构方案时，必须进行结构性能试验，待取得较好的结果后，方能在机床上采用；必须进行技术经济分析。只有在技术经济上效果明显，才能采用专用机床实现单机自动化。自动线是由流水生产线方式发展而来的。20 年代美国Henry Ford 创立了汽车工业的流水线，由此揭开了现代流水生产的序幕。福特流水线的主要内容可以包括以下两个方面：实施零件和产品的标准化，设备和工具的专用化以及工场专业化。为了追求高效率和低成本，福特认为首先要将生产集中于唯一最佳的产品型号，提出了所谓的“单一产品原则”，福特汽车公司曾在20 年间连续生产T型汽车，由此而奠定了现代流水生产线的基础。这种“单一产品原则”在当今市场需求日益多样化的环境下也许已不再适用，但在当时的经济条件下却适应了美国的国情，福特汽车公司也由此而迅速发展起来。零件标准化是产品标准化的进一步发展，目的在于提高零部件的互换性，减少零件种数和扩大生产批量，零件标准化后，便于分别组织专业化工厂或车间制造，这样可以采用高度专门化的设备和工具，从而达到生产的高效率。由于工人的作业活动是不断地重复同一作业，所以作业和操作也可以实现标准化。创造了流水作业的生产方法，建立了传送带式的流水生产线。由于传送带的广泛应用，使得原材料均可在使用机械装置搬运的移动中，加工成为各种零件。而部件装配和汽车总装配，则采用移动装配法完成。由于把生产工序分细，大大提高了操作熟练程度和劳动生产率。作业的速度也为传送带的速度所规定，借助于传送带的应用，使生产过程的各项作业能在同一时间进行，并且各种零部件在各条流水线的投入和产出互相衔接配合，不至于发生在制品过多或不足的现象，恰能保证总装配线的需要，形成同步化的流水生产体系。自动线生产是指工件按照一定的工艺路线，顺序地通过各个工作地，并按照一定的生产速度(节拍)完成工艺作业的连续重复自动生产的一种生产组织形式。自动线生产的基本特征如下：工作地专业化程度高，在自动线上固定地生产一种或几种工件，而在每个工作地上固定完成一道或几道工序。生产具有明显的节奏性，即按照节拍进行生产。所谓节拍，是指自动线上出产相邻两件制品的时间间隔。各道工序的工作地设备数量与该工序单件工时的比值相一致( 若不一致则需要临时缓冲库) 。工艺过程是封闭的，并且工作地设备按工艺顺序排列成链索形式，工件在工序间作单向。工件如同流水般从一个工序转到下个工序，消除或最大限度地减少了工件的因等待加工而耽搁的时间和机床设备加工的间断时间，生产过程具有高度的连续性。工件从进入加工工位到所有工位操作完成，均在主控制器的控制之下自动完成，这种自动过程不仅包括工件的流动自动化控制，还包括机床的加工全过程的自动化控制。仅满足上述前面6项特征的生产线，只能称之为流水生产线，还不能称之为自动生产线。加工设备由专用自动化机床或组合机床组成的，能加工固定一种或少数几种相似零件的自动线称之为刚性自动线。加工设备由数控机床或加工中心等组成的可加工多品种少批量零件的自动线称之为柔性自动线。在刚性自动化生产条件下，生产过程的连续性、平行性、比例性、节奏性都很高，所以它具有可以提高加工设备专业化水平、提高劳动生产率、增加产量、降低产品成本、提高生产的自动化水平等一系列优越性。但是反过来也有不少不利的地方，例如：由于设备高度专用化，对产品的变化缺乏适应力；一旦在某处发生设备故障，就有可能导致全线停车，带来较大的损失；生产率的调整幅度不可能很大；技术改造困难较大等等。我国轴承制造业现状：轴承是关系国民经济发展的关键机械基础件，其技术水平和产品质量对主机的性能和质量有着重要的影响，被誉为机械的“关节”。改革开放以来，我国轴承产品水平和制造技术水平有了长足进步，与重点主机配套能力有了很大提高。但与工业发达国家相比，我国轴承制造业的整体水平还存在着相当大的差距组织结构散乱差，重复建设严重，生产集中度低；产品设计水平低，新产品开发跟不上主机发展需求；制造技术落后，尺寸散差大，振动噪声大，性能一致性差，寿命可靠性低；产品档次低，价格乱，竞相压价争市场，国际竞争能力差。为主机配套和维修的一些高技术含量的轴承主要依靠进口，而出口轴承则主要是低档通用轴承。轴承制造业的这种落后状况，已经成为制约机械工业发展的重要因素之一。轴承装配自动线：国家已将汽车制造业列为国民经济的支柱产业，我国目前的汽车保有量为25003000万辆，年产量170万辆，轴承是汽车的主要配套件，轴承制造业的发展必须与汽车制造业同步甚至超前。因此，提高轴承装配的技术水平和自动化程度已经迫在眉睫。轴承属于量大面广通用性强的机械基础件，轴承套圈一般以轴对称的多个回转面、环面的相互组合为其主要的几何特征，特别适合自动化装配。轴承装配（含轴承成品的自动检测、自动包装）自动线一直是困扰着技术进步的难题。在国外著名的轴承公司，这项技术已实际成功应用多年。而国内靠国外引进，而使用效果仍不能令人满意。因而研发轴承装配自动生产线，并与轴承的磨削自动生产线有机连接，对于提高轴承的生产效率和产品质量，减少工序流动中的轴承零件的数量，减少人工干预的影响、降低成本，意义是显著的。由于轴承的品种很多，不同的品种，自动装配线各有特点，因而轴承行业对轴承装配的数控设备的多样性提出了要求。 万向节滚针轴承特点：目前后驱动汽车上应用最广的一种普通万向节由万向节叉、十字轴等基本零件构成。十字轴装配在万向节叉上做连接，十字轴的轴头上装有滚针轴承，当轴头接入万向节叉时，十字轴与万向节叉之间就可以有相对旋转，也就产生了多角度变化。万向节叉上的花键连接又可以做小许的轴向移动，这样就适应了夹角和距离同时变化的需要。十字轴的轴头上装有的这种滚针轴承，就是我们此次设计的装配对象。滚针轴承可分为具内圈（NA）和不具内圈（RNA）两种结构。如果机轴上的滚道可以淬硬及研磨，则宜用无内圈的滚针轴承，由于不需内圈，因此机轴直径可以加大，刚性也可增加。机轴相对于轴承箱的轴向位移量则由轴向滚道宽度决定。只需将机轴滚道机削加工到适当的尺寸和形状精度，即可获得具有较高运转精度的轴承配置。若机轴淬硬及研磨机轴不可能，或不经济时，可采用带内圈的滚针轴承。这时机轴对轴承箱的轴向位移限制在一定的限度内。若需要较大的位移，可使用加长型内圈取代标准内圈。满装滚针轴承：分为RNAV（无内圈）、NAV（带内圈）两种。不带保持架，装满滚针，适用于截面高度较低，而又需承受较大载荷的场合。滚针轴承一般只承受径向负荷，不能承受轴向负荷。当有轴向负荷时，应和其它轴承组合使用，它不限制轴或外壳的轴向位移。安装轴承时，应注意轴和壳孔中心的平行，轴承的外圈轴线和内圈轴线不允许倾斜，否则会使滚针和滚道面的线接触破坏。滚针轴承的极限转速较低，在主机转速较高的情况下，应尽量选用带保持架的滚针轴承。和其它类型的滚动轴承相比，在径向尺寸相同的情况下，滚针轴承的负荷容量最大，它的刚性较高，但摩擦力矩也较大。国内发展：在国内，南通市工农路正扬商务有限公司已于 2005年9月23日在商贸机会中国轴承机械网发布关于自动滚针轴承装针机（专利）的技术转让信息，寻求商业合作。但是使用效果仍不能令人满意，所以我们对此项课题进行深入的专门设计研究。3工作内容和要求：设计要求： 装针机以CA141汽车传动轴中的万向节滚针轴承为装配件。 机械手每分钟装配成品十只。工作量： 主机及零部件设计4张A0图纸（草图）。 设计说明书一份（20000字）。 外文翻译（5000字）。 上机绘制4张A0图纸（CAD）。4课题的重点和难点：课题重点：本课题内容为设计研究CA141汽车传动轴中万向节滚针轴承的自动装针机。整个装配系统采用卧式装针方式，轴承外圈采用直立状态，开口端正对滚针进给端，滚针采用横向进给方式，即采用一特殊装配装置使滚针安排成圆周均布状态，其圆周直径和轴承外圈内壁直径相同，然后采用一推套把滚针推入轴承内，滚针只需排入轴承内壁即可，从而完成整个装配过程。为了实现上述方案，本装配系统采用五大机构：滚针的自动上料机构，轴承外圈的上料机构，装配和卸料装置，凸轮机构，传动系统。滚针需要整齐的排序，此机构采用槽隙定向的上料机构原理，采用一特制齿形轮进行上料，轴承外圈上料机构采用重心偏移法定向的料斗装置原理，具体采用特制一斜边推块上料机构，装配和卸料机构采用一汽实习时所见之装配原理，并进一步改进而成。为了实现装配和卸料机构中推套的运动，采用一圆柱凸轮摆杆机构。由于本系统所需转速低，各轴之间传动比要求低，所以采用链传动，并且结构简单紧凑，对本系统特别适用。因此，解决滚针的自动上料机构，轴承外圈的上料机构，装配和卸料装置，凸轮机构，传动系统五大机构的典型机构设计成为本研究课题的重点。课题难点：本课题设计的自动机床主要包含两部分装置：自动装配工件装置和自动装卸工件装置。如果设计过程中其中一部分功能不能实现，就只能称之为半自动机床，从而也就不能完成连续的加工循环，因此两部分相辅相成，缺一不可。所以如何选择滚针的自动上料机构，轴承外圈的上料机构，装配和卸料装置，凸轮机构，传动系统五大机构的设计方案，并实现整个系统的全自动化成为了本研究课题的难点。5可能用到的主要知识和技能：机械原理，机械设计，机械制造，C语言程序设计，工程图学，机床自动化与自动线知识，自动装配知识，机电一体化知识，AutoCAD 绘图技能，CATIA建模能力，ANSIS有限元分析，ADAMS仿真分析等技能。6需要自学的知识和技能：机床自动化与自动线知识，自动装配知识，机电一体化知识，AutoCAD 绘图技能，CATIA建模能力，ANSIS有限元分析，ADAMS仿真分析等技能。二 工作计划： 调研，译文，参考资料 总体布置，草图，开题报告 总体设计，总装图 部件设计，相关计算 零部件设计，论文 修改，完善图纸、论文，准备答辩三 参考文献：1 英 R.M.韦布， B.D.乔特.自动装配图集料斗进给装置与控制系统.上海：上海科学技术出版社，1983.72 英 R.M.韦布，B.D.乔特.自动装配图集传送机构.上海：上海科学技术出版社，1983.73 英 R.M.韦布，B.D.乔特.自动装配图集定向机构与擒纵装置. 上海：上海科学技术出版社，1983.74 英 R.M.韦布，B.D.乔特.自动装配图集工件移置机构.上海：上海科学技术出版社，1983.75 华中工学院机械制造教研室.机床自动化与自动线.北京：机械工业出版社，1981.36 工业机械手图册.北京：机械工业出版社，1978 7 Techniques in automated assembling the state of the art，12th June 1985，The Bowater Conference Centre，Knightsbridge，London，UK 8 An automated assembly system for a microassembly station，Computers in Industry，Volume 38，Issue 2，March 1999，Pages 93-102 ，A. Mardanov，J. Seyfried and S. Fatikow9 A microrobot-based automated micromanipulation station for assembly of microsystems，Computers in Industry，Volume 36，Issues 1-2，30 April 1998，Pages 155-162，Sergej Fatikow and Mirko Benz8本科生毕业设计（论文）翻译资料中文题目： 以微型机器人为基础的自动化 显微操作装置为微系统装配 英文题目： A microbot-based automated micromanipulation station for assembly of microsystemsA microrobot-based automated micromanipulation station forassembly of microsystemsSergej Fatikow Mirko BenzAbstract：The development of new types of miniaturized and microrobots with human-like capabilities play an important role in different application tasks. One of the main problem of present-day research is, for example, to assemble a whole microsystem from different microcomponents.This paper presents an automated micromanipulation desktop station including a piezoelectrically driven microrobot placed on the highly-precise xy stage of a light microscope, a CCD-camera as a local sensor subsystem, a laser sensor unit as a global sensor subsystem, and a Pentium PC equipped additionally with an optical grabber. The microrobot has three piezoelectrically driven legs and two autonomous manipulators as endeffectors; it can perform highly-precise manipulations （with an accuracy of up to 10 nm） and a nondestructive transport （at a speed of several mm/s） of very small objects under a microscope. To perform manipulations automatically, a control system, including a task planning level and a real-time execution level, is being developed. （C）1998 Elsevier Science B.V. All rights reserved.Keywords： Microrobots; Microassembly; Automated desktop station; Assembly planning; Piezoactuators1.Introduction：There is a growing need for miniaturized and microrobots worldwide. Due to the enormous breakthroughs in conventional robotics and in the microsystem technology (MST),everyone is convinced that the development of remote-controlled or autonomous microrobots will lead to improvements in many areas. Above all, positive results are expected in medicine (microsurgery),manufacturing (microassembly, inspection and maintenance), biology (manipulation of cells) and testing/measuring technique (VLSI) . Medicine is one of the application fields which would profit by the microrobotics the most. The attention lies on artificial organs (prosthetics) , laparoscopy, implantable drug delivery systems (diagnosis and therapy systems) , telemicrosurgery, etc. The minimal-invasive surgery developed into an important field of medicine during the last years.Smaller and more flexible active endoscopes are needed in order to replace human hands, respond to outer incidents, penetrate into a body or a vessel through natural bodily orifice or a small incision by remote control, where they perform complex in-situ measurements and manipulations. In order to meet these requirements, microprocessors, several sensors and actuators, a light source and possibly an image processing unit should be integrated into an intelligentendoscope. Biotechnology requires special microstructured active tools which are able to perform micromanipulations like the sorting or reunion of cells or the injection of a foreign body into a cell under a microscope. In the gene research and the environment technique （cells as indicators for harmful substances）, precise and gentle manipulation of single cells are also required. Industry and especially manufacturing and measuring techniques need highly sensitive testing methods in the m-range. An important task represents, for example, the inspection of wafers, where several check points have to be contacted by a temperature or voltage probe. The same is valid for inspection robots which are used in inaccessible or dangerous terrain in order to detect leaks or flaws and make repairs （e.g., in pipelines）。The adoption of MST-related developments by the industry has already demonstrated which kind of problems occur with the mass production of microsystems. These systems usually consist of microcomponents of different materials which are produced with various microtechniques; this leads to one or several very precise assembly step （s）of theindividual components. The assembly of microsystems, i.e., the non-destructible transport, precise manipulation or exact positioning of microcomponents is becoming one of the most important applications in microrobotics.2. Manipulation of microobjects：The availability of highly precise assembly processes will make it easier to economically realize operable microsystems. In order to efficiently produce microsystems and components in lot sizes or by mass-production techniques, it is absolutely necessary to introduce flexible, automated, precise and fast microassembly stations. Different concepts are being followed to do micromanipulation for particularclasses of application.Purely manual micromanipulation is the most often used method today. In medicine and biological research, it is used exclusively. Even in industry, microassembly tasks are very often carried out by specially trained technicians, who, for example, preposition assembly parts using screws and springs, then position the parts with tiny hammers and tweezers, and finally fasten them in the desired position. However, with increasing component miniaturization, the tolerances become smaller and smaller, and the capabilities of the human hand are no longer adequate.The application of partially automatic micromanipulation systems of conventional size, which are teleoperated; thereby, the hand motions of the human operator are translated into finer 3D motions for the manipulators of the manipulation system by means of a joystick or mouse. Here, the dexterity of the human hand is supported by sophisticated techniques. However, the fundamental problem of the resolution of the fine motion and of the speed remain, since the motion of the tool is a direct imitation of that of the operators hand.The use of automated multifunctional micromanipulation desktop stations supported by miniaturized flexible robots which employ MST-specific direct- drive principles. These robots could be mobile and are able perform manipulations in different work areas. The transport and micromanipulation units performing the assembly may be integrated onto one chip. As opposed to the aforementioned micromanipulation technique, there is no direct connection between the operators hands and the robot. The assembly steps may be carried out with the help of closedloop control algorithms. The human assigns all tasks to miniaturized assembly mechanisms and, by doing so, tries to compensate for his limited micromanipulationcapabilities. Many microrobots can be active at the same time in a desktop station.The use of many flexible nanorobot systems which solve the manipulation tasks in close cooperation. Here, the robot size is comparable to that of the manipulated object. This concept could be based on the human behavior, but its realization lies in the distant future. In general, manipulations vary from an application to another. However, approximately the same operation sequences are used in every case. They are: grip, transport, position, release, adjust, fix in place and processing steps like cutting, soldering, gluing, removal of impurities, etc. In order to be able to carry out these operations, corresponding tools are needed, such as microknives, microneedles to affix objects, microdosing jets for gluing, microlaser devices for soldering, welding or cutting, different types of microgrippers, microscrapers, adjustment tools, etc. Microgrippers play a special role, since they considerably influence the manipulation capabilities of a robot. Microgrippers can clamp, make a frictional connection or adhere to the material, depending on the physical and geometrical properties of an object. Adapting a gripper to the shape of the object to be gripped is often the best solution in the microworld, even at the cost of flexibility. This allows handling of a workpiece having a complex shape, such as a gear. Thereby, the gripper securely attaches to the contour of the part. For small, smooth parts, a suction pipette might be a practical tool. If the upper surface of a workpiece must not be touched or gripped due to technological reasons, it can be protected by a corresponding form-fit of the pipette hole. For contour clamping and frictional connections in manipulations involving fragile parts, elastic grippers made of soft plastics are preferred over metal grippers. Due to the variety of task-specific gripping tools in automated micromanipulation systems, a suitable gripper exchanger system might be necessary.It should be mentioned that it is not always possible to adapt conventional manipulation methods to the demands of the microworld. A major problem is the effect of various forces which is completely different from the macroworld. Gravitation only plays a minor role in the microworld, but attractive forces,such as electrostatic forces or Van-der-Waals forces, are significant. Liquid surface tension can also act as an attractive force in micromanipulations if humidity is high or if a manipulator is wet. This unusual sensitivity to forces can be very irritating in a micromanipulation station. For example, it can be easier for the robot to grip and manipulate an object than to release it afterwards. On the other hand, such an adhesion force can be used to develop new gripping methods which can fundamentally differ from the familiar mechanical and pneumatic methods. In Ref. 【1】 , several interesting ideas were shown for adhesive gripping, such as electrically charging a manipulator or wetting a gripper surface by special micromachined orifices.The performance and degree of intelligence of a micromanipulation station is low for a manual operation; it improves by going to a teleoperation and further to an automation; this is similar with conventional robots. Most micromanipulation investigations today focus on the improvement obtained by going from a purely manual to a teleoperated system【24】. As previously mentioned, attempts are being made to make the transmission of effects from the microworld to the operator as realistic as possible. It is important that the operator has the entire scene in his field of view and that he can see the workspace from different angles. Besides visual information, the operator should also be able to receive acoustic and force signals if possible; this may increase the accuracy of his movements and avoid destroying the microobjects. For this, force sensors are needed which are implemented into the microtools (e.g., a microgripper) . Suitable solutions are now being sought after to realize such sensors【5】.3. Development of a flexible micromanipulation Station： Typically, in a conventional automatic or semiautomatic assembly station, standardized mechanical parts are assembled in well-defined work positions. The robots performing the work are usually of multi-axis arm design or they are gantry systems,usually driven by DC motors. Today, it is being attempted to use these type of familiar systems for handling and assembling of miniaturized components with dimensions in the millimeter range. For example, a modular microassembly system with four degrees of freedom is currently being developed【6】.With increasing workpiece miniaturization, however,it becomes more and more difficult to use conventional manipulation robots for assembling microsystems.The manipulation accuracy is mechanically limited for conventional robots, since disturbing influences which can be neglected in the microworld, such as small fabrication defects, friction, thermal expansion or computational errors, play a large role in the microscale. Due to the mechanical drives for the actuators motions, these robot systems must undergo regular maintenance and are subject to mechanical wear, which makes them expensive. The assembly process in the microworld is influenced by the mass-related dynamics of the objects being handled. Different processing conditions exist for manipulating microscopically small components. The positioning accuracy and the tolerances of the micro-components lie in the nanometer range, a few orders of magnitude lower than in conventional assembly. These accuracy requirements can only be obtained with manipulators which have highly accurately drives utilizing the MST and advanced closed-loop control. Therefore, a microrobot-based flexible desktop station is of particular interest. A new concept for an automated micromanipulation desktop station is now being investigated 【7】. The main part of the station are the piezoelectric microrobots which were presented in Refs.【8,9】.Each robot has a micromanipulating unit integrated in a mobile platform, which makes it capable of moving and manipulating. Tools can be easily exchanged. These robot properties are good preconditions for the complete sensor supported automation of manipulation processes in the microassembly station. Owing to the flexibility of the microrobot, this multifunctional desktop station can also be used for other things, such as handling biological cells or actively testing microelectronic chips with temperatureor or voltage probes. This flexibility can also be used to accommodate several robots in the station, which can cooperate and carry out manipulations. The schematic design of the micromanipulation desktop station is shown in Fig. 1. The operations of the microassembly station may be described as follows.The parts are first separated and placed into magazines in order to have them correctly positioned for automated assembly. This is necessary, since microcomponents are often delivered as bulk material. This step can also be automated in a powerful microassembly station, to avoid the expensive manual handling.A microrobot removes a micromechanical component from the magazine and transfers it to a processing cell where the component can then be prepared for microassembly by other microrobots. In this step, adhesives or solder can be applied, adjustment marks taken, or other simple operations carried out.After the part has been processed, it is gripped by a robot and brought to a microassembly cell.If necessary, the same operations are repeated many times in order to fetch the other necessary components from a supply container and prepare them for assembly.All components are positioned correctly, affixed to each other and adjusted. Thereafter, they are joined together by various interconnection techniques, e.g., laser spot welding, gluing, insertion, wire bonding, etc.After assembly, a robot brings the finished component either to another work station or a microassembly cell for further processing or to an inspection cell, where all functions of the microsystem are being tested. Finally, the finished system is transported to a storage. The entire assembly process occurs in the desktop station under an automated light-optical microscope which is equipped with a RS232-standard interface. The sphere of operation includes a highly precise positioning table with two translational degrees of freedom （xy plane ）and a glass plate fixed on top of it. By controlling the movements of the table, each individual working cell on the glass plate can be brought under the microscope. The station has a central computer （Pentium PC） which is used for task-specific assembly planning. The necessary operational steps are defined and carried out successively. The commands of the central computer are then further processed on a lower control level, using a parallel computer system with the C167 microcontrollers. This system was reported in Ref.【10】. The central computer is coupled with the parallel computer system over serial and parallel interfaces. These commands are resolved into command sequences for all active system components （robots, microscope and positioning table） by an execution planning system, and finally performed. Thanks to the parallel computer system, the generated commands can be executed in parallel, which makes the microassembly station capable of real-time behavior. The movements of the positioning table, different microscope functions （objective changing, focusing, lighting） and every piezoactuator are controlled. In order to automatically control the manipulation processes in the microassembly station, there must be sensor feedback. Therefore, the light-optical microscope is equipped with a CCD camera. The camera and the microscope form the local sensor system with the help of which the position of the microobjects and the robot tools must be determined. For this it supplies visual information on the robot tools and the microobjects to the central computer. The gross position of the robots on the glass plate is detected by a global sensor system which includes a laser measuring unit and another CCD camera. The visual sensor information from both the local and the global sensor systems is used by the control algorithms to generate new commands for the robots, microscope and the positioning table. Vision is supported by a frame grabber in connection with fast real-time image recognition and processing systems. The vision parameters are passed on to the parallel computer system. They are used as a set point for the control loop.4. Planning of the microassembly：The above description of microassembly station activities is very general and perhaps makes the assembly process sound too simple, but many problems must first be solved. After a microsystem has been designed, all tools and techniques necessary for its automated assembly should be determined, so that the microassembly station can be set up for a taskspecific operation sequence. The specified techniques and tools must take the geometry of the components of the microsystem into consideration, as well as their physical properties, such as rigidity, texture and temperature stability. Therefore, the planning phase of an automated microassembly requires a high degree of competence. Pure top-down planning in a microassembly station seems to be impossible since the selected robots and their tools determine the flexibility and the degree of automation of the station, and therefore, also determine its performance limits. One possible planning strategy is the meet-in-the-middle strategy; thereby, this intermediate interface can be on the tool level. Indeed, the main functions of assembly planning are the determination of the task-specific sequences of the elementary operations and the selection of necessary tools for carrying out the work (top-down planning) . On the other hand, the tools and the elementary operations needed for the assembly of a microsystem also require that the microrobots have specific functional properties, which may influence the robot design (bottom-up planning) . As mentioned, for more complex assembly tasks several robots must be used together in the desktop station. Individual robots can, for example, be specializedto take care of one or more certain assembly operations. In this case, the robots carry out their manipulation tasks in a sequence which is defined during the planning phase. For more complex operations, robots can be pooled together to do simultaneous actions with the help of several different tools (e.g., transferring or gripping of objects) . In this case, the operators commands are no longer transmitted one-by-one to the manipulator arms, but are applied to the entire multirobot system, e.g., by means of the one-by-multiple method 【11】. Here, one microrobot acts as the leader of the group, it gets micromanipulation assignments from the operator and then coordinates the other microrobots to complete the task using an automatic process for communicating with the robots and then giving them the corresponding commands. If the cooperating robots are equipped with sensors, new object manipulation methods can be developed, which are based on the distributed observation of the objects. The object could be observed from two view points, for example, which would supply exact data concerning the objects movements. The main problems of the practical realization of the micromanipulation desktop station employing several microrobots are caused by the assembly planning on the uppermost control level, the task-specific distribution of the necessary robots and tools, as well as their movements and forces, which should allow the assembly process to run error and collision-free. The planning system of the station, which is being developed 【12】, consists of three main module: system interface, assembly task planner and assembly execution planner (Fig. 2) . The modules are supported by a knowledge base which includes knowledge on the task specification, an assembly model of the microsystem, the specification of existing microrobots and their tools, a world model (micro and macro) and the current station state obtained by the sensor system. The planning process of the assembly task planner is successively performed in three planning levels. In the first step, an assembly graph is generated. Each node of the graph represents one particular assembly operation and the edges represent the relations between two operations. At the next level, a sequence of executable assembly operations( like operations for pick and place, push, turn, etc). is planned. Thereby the order restrictions of the assembly graph have to be considered. The geometry of the working area and the resources available such as microrobots and their tools must be taken into account during this planning step. After obtaining the action sequence, a task decomposition has to be done. The action sequence is decomposed into subplans for microrobots based on their operational capabilities. The actions generated by the assembly task planner are then particularized to the specific conditions in the working area by the assembly execution planner. The execution planner generates a motion sequence of the platform and the endeffectors for each microrobot which is necessary to execute the planned actions. The motion planning for each microrobot is performed by its own execution subplanner. At this planning level, three types of collision-free motion are distinguished: gross motions of the robot platform to transport workpieces from one place to another, fine motions of the robot endeffectors to graps or release a workpiece, and fine motions of the whole robot( platform+endeffectors) to manipulate the microobjects. The execution planning done by all microrobots subplanners must be supervised to ensure the consistency of the plans. The main function of the sensor subplanner is to manage the gross motion and fine motion sensor systems in regard to the actual action.5. Conclusions and future works：Coming to a conclusion, it can be stated that presently, no easy solutions exists for assembling microparts, especially when taking into consideration the hardware and software and the costs involved. It can be clearly seen, however, that the availability of versatile automated microassembly stations will greatly contribute to the long-awaited industrial breakthrough of MST. A current industrial success that encourages the development of MST is the rapid progress of microelectronics, where automated production methods led to the birth of an entire new industry. This development is a motivating example for MST researchers, who are the innovators in the interdisciplinary field of microassembly. Such microassembly stations need an adaptable and hierarchically distributed control system, which make it possible to quickly initiate a cooperation to an immediate request between the operator and a robot or between different robots. It is nearly impossible to explicitly program every possible scenario that can happen in the complex operation surrounding. In a flexible system, the individual robots should be able to adapt their behavior to the surrounding and react flexibly to new situations. Decentralizing of a control system is also of advantage to facilitate the robots ability to learn. Machine learning of single robots has been investigated for a long time, but the learning process of a group of robots is not known. An important concept in multirobot systems seems to be learning by observation. Different simulation tools can be helpful in assembly planning. In order to be able to evaluate the assembly task and choose the best strategy, various operating sequences can be tried out by using CAD models of the microrobots and workpieces. Evaluation criteria could be freedom of collision, best use of resources, duration of assembly, compliance with technological parameters, etc. However, it is not always possible to get help from a simulation module. As long as there is only path planning involved, there are many ways of finding a solution. When no trajectory restrictions are given other than that a goal has to be reached, collision avoidance methods based on fuzzy-logic seem to be suitable. But it is very difficult to simulate the force distribution between several robots which cooperate in a manipulation task. Another unsolved problem is simulating the task-specific manipulation of microobjects, for example, for the purpose of testing the assembly task of a given robot and a tool, or to determine how much time the process will take. To do this, it is necessary to know the forces occurring in the microworld and the dynamic behavior of microobjects. For neither of these problems, there are models available so that dynamic assembly planning cannot be carried out today.Acknowledgements：This research work was performed at the Institute for Real-Time Computer Systems and Robotics （Headed by Prof. Dr. U. Rembold, Prof. Dr. H. Worn, and Prof. Dr. R. Dillmann） , Faculty for Computer Science, University of Karlsruhe, 76128 Karlsruhe, Germany.References：【1】F. Arai, D. Ando, T. Fukuda, Y. Nonoda, T. Oota, Micro manipulation based on micro physics, Proc. of IEEErRSJ Int. Conf. on Intelligent Robots and Systems IROS , Pittsburgh, PA, 1995, pp. 236241.【2】M. Mitsuishi, K. Kobayashi, T. Nagao, Y. Hatamura, T. Sato, B. Kramer, Development of tele-operated micro-handlingrmachining system based on information transformation, Proc. of the IEEErRSJ Int. Conf. on Intelligent Robotsand Systems IROS , Yokohama, 1993, pp. 14731478.【3】H. Morishita, Y. Hatamura, Development of ultra precise manipulator system for future nanotechnology, Proc. of Int. IARP Workshop on Micro Robotics and Systems, Karlsruhe, 1993, pp. 3442.【4】T. Sato, T. Kameya, H. Miyazaki, Y. Hatamura, Handeye system in nano manipulation world, Proc. of Int. Conf. on Robotics and Automation, Nagoya, 1995, pp. 5966.【5】M. Horie, H. Funabashi, K. Ikegami, A study on micro force sensors for microhandling systems, Microsyst. Technol. 1 3 1995 105110.【6】U. Gengenbach, Automatic assembly of microoptical components, Proc. of SPIE International Symposium on Intelligent Systems and Advanced Manufacturing, Boston, MA, Vol. 2906, 1996, pp. 141150.【7】S. Fatikow, A microrobot-based automatic desk-station for assembly of micromachines, Proc. of the 12th Int. Conf. on CADrCAM Robotics and Factories of the Future, London, 1996, pp. 174179.【8】B. Magnussen, S. Fatikow, U. Rembold, Micro actuators: principles and applications, in: M. Glesner Ed. , Aufgaben der Informatik in der Mikrosystemtechnik, Schlo Dagstuhl, 1994.【9】S. Fatikow, B. Magnussen, U. Rembold, A piezoelectric mobile robot for handling of microobjects, Proc. of the International Symposium on Microsystems, Intelligent Materials and Robots, Sendai, 1995, pp. 189192.【10】B. Magnussen, A parallel control computer structure for complex high speed applications, Proc. of the 1st IEEE Int. Conf. on Engineering of Complex Computer Systems, FL, 1995, pp. 385388.【11】S. Hirai, S. Sakane, K. Takase, Cooperative task execution technology for multiple micro robot systems, Proc. of the IARP Workshop on Micromachine Technologies and Systems, Tokyo, 1993, pp. 3237.【12】S. Fatikow, R. Munassypov, An intelligent micromanipulation cell for industrial and biomedical applications based on a piezoelectric microrobot, Proc. of the 5th Int. Conference on Micro Electro, Opto, Mechanical Systems and Components MST , Berlin, 1996, pp. 826828.Sergej Fatikow, born on March 5, 1960 in Ufa, Russia, studied computer science and electrical engineering at the Ufa Aviation Technical University in Russia, where he received his doctoral degree in 1988 with work on intelligent control of complex nonlinear systems. Then he moved to the Institute for Real-Time Computer Systems and Robotics at the University of Karlsruhe in Germany where he is working as an assistant professor.Since 1994, he is a leader of theresearch group Miniature and Micro Robots. His research interestsinclude different aspects of microrobotics, microassembly, intelligent planning and control in microassembly cells, and neuro-fuzzy-based information processing.Mirko Benz was born in Offenburg, Germany in 1969. He studied computer science at the University of Karlsruhe, Germany from 19901996 where hespecialized in CIM Computer Integrated Manufacturing and AI ArtificialIntelligence and took part in a traineeshipsity of South Australia, Australia. As a student member of up Miniature and MicroRobots at the Institute of Real-TimeComputer Systems and Robotics, he has contributed to the investigation ofmicrosystem technology and microrobotics and is co-author of several publications. Currently,he is working for the IT group of the Hewlett-Packard in Boeblingen, Germany.以微型机器人为基础的自动化显微操作装置为微系统装配摘要：小型化的新类型的发展和智能型微型机器人在不同的应用程序任务中扮演着重要角色。现在研究的主要问题之一是,例如，装配来自不同的微成份的一个整个的微系统。这篇论文说明一个包括放在精密x-y坐标的光学显微镜上的一个压电驱动机器人的自动化显微操作桌面装置，一部电压耦合元件照相机作为一个局部的感知器次系统，一个激光感知器单位作为一个整体的感知器次系统，额外配置一台带有光学抓帧器的奔腾电脑。这个微型机器人有三压电驱动支架和两个活动自如的机械手作为终结者。它能在显微镜下对很小物体执行精密的处理（准确度10nm以下）和非破坏性的运输（以若干nm/s的速度）。为了自动地执行操纵，一个控制系统,包括一个任务计划标准和一个即时实施标准, 正在被发展。关键词：微型机器人 显微装配 自动化桌面装置 装配计划 压力致动器1 介绍：全世界对小型化和微型机器人的需求在增加。由于巨大的断缺，在传统的迹器人学和微系统工艺学中，每个人都相信遥控的发展或者自主的机器人将在许多领域引导进步。最重要者，积极的结果在药 (显微外科) 被期望,制作 (微型装配，检查和养护), 生物 (细胞的操纵) 和测试的/测定的技巧 (VLSI)。药是一种得益于微型机器人学最多的应用领域之一。关注多在人工的器官 (义肢学) ，腹腔镜，可深植的药物输出系统 (诊断和治疗体系) ，可视显微手术,等等。在过去的几年间，极小探入式手术在药学领域获得极大的发展。更小和更多易曲的有效内视镜被需要去替代人类的手，回应外部的事件, 经过自然的身体孔刺入一个车体或者一个船舶或者远距控制的一个小切口,在这些地方他们执行复杂的现场测量和操纵。妥善符合这些需求，微处理机, 一些感知器和引动器, 一个光源和可能地一个图像处理单元应该被整合进入一智能的内视镜。生物技术需要特别的有微细构造的有效工具,这种工具能够执行如在显微镜下细胞的分类或重聚或异物的细胞注入的显微操作。在基因研究和环境技术（细胞作为有害物质的指示剂），单一细胞的精密的和温和操纵也被需要。工业和特别的制作和度量技术在微米范围内需要高度敏感的测试方法。一个重要的任务表现,例如，晶圆的检查,一些核对点必须被一个温度或电压探针连络。同样适用于应用在难接近的或者危险的地形为检测缺陷和漏洞并修理的检测机器人（例如，在输送渠道）。工业上微系统相关技术发展的采用已经证明了哪一类的问题在微系统的大量产品中发生。这些系统通常有与各种不同的微技术一起生产的材料的微成份;这就引发了一个或一些个别组件的精密装配步骤。微系统的总成,也就是，无可破坏的运输, 精密的操纵或微成份的正确定位正成为微型机器人学中最重要的应用之一。2 微物质的操作：高度精密的总成程序的可行性将会在经济上比较容易地实现可实施的微系统。为了有效地生产大尺寸的微系统和组件或者藉着大量生产技巧，了解有柔性的，自动化的，精密的和快速微装配的装置是完全必要的。不同的观念正在被接受去为应用程序的类别做显微操作。纯粹手动的显微操作是当今最常用的方法. 在药和生物的研究中，它独有地被利用。尤其在工业，微型装配任务时常由特别训练的技术员运行，他们总成零件使用螺丝和弹簧，然后用极小的锤子和镊子放置零件, 而且最后在被需要的位置中夹紧它们。然而，藉由递增组件的小型化，公差变得越来越小，而且人类手的能力不再精确。传统尺度的部份自动显微操作系统的应用程序, 是可视的; 藉此，人类操作者的手动作被为操纵系统的操纵者藉由一个摇杆或鼠标转变为较相似的3D立体动作。在这里，人类手的技巧由复杂技术支持。然而，相似动作和速度保持是需要解决的基本问题,因为工具的动作是操作者的手的直接模仿。自动化的多功能的显微操作桌面装置的使用被应用特别微型操作技术的直接传动原则的小型化的柔性机械手支持。这些机器人应该是移动的和能在不同的工作区域中执行操纵。运输和执行总成的显微操作单位可能在一个晶片之上被整合。相反上述的显微操作技巧, 没有操作者的手和机器人之间的直接连结。总成步骤可能与闭环控制运算法则的辅助一起运行。人类为小型化总成机构分配所有的任务，并且藉由如此执行，试着为他的有限显微操作能力作差补。许多微型机器人在一个桌面装置中能同时有效。解决在紧密合作中的操纵任务的许多柔性的纳米机器人系统的使用。在这里，机器人尺度对被操纵的物件是可比较的。这一项观念应该以人类行为学为基础, 但是在遥远的将来它必将实现。大体上，操纵从一个应用程序执行到另外一个。然而，大约相同的运作顺序在每个情形都可以被用。 他们是: 手柄, 运输,放置,放松,调节, 适当地固定，和加工步骤像切削, 锡焊, 黏合, 杂质的排除, 等等。为了能够运行这些运作, 对应的工具像微小刀具，微小滚针附黏物件，微小剂量喷射,微激光方法对于软焊，熔接或者切削，微小抓爪器，微小刮刀的不同类型，调整用工具,等等被需要。微小抓爪器扮演一个特别的角色,因为他们很影响机械手的操纵能力。微小抓爪器能夹紧, 作磨擦力联接或者黏附在材料之上,依赖物件的物理学和几何学性质。使一个夹子配合物件的形状跟踪抓紧是在显微世界中最好的解决方法, 甚至以韧性为代价。这允许一个有复杂形状的工作区的处理，如一个齿轮。藉此，夹子安全地附上零件的等高线。 对于很小，光滑的零件，一个吸取移液器可能是一个实际的工具。如果工作件的上表面由于技术的原因不能被接触或者抓紧, 它能被一个移液器孔对应模型进行保护。 对于包括易碎零件的等高线定位和磨擦力联接的操纵，用软式塑料做成的柔性夹子替代金属夹子被偏爱。由于在自动化的显微操作系统中采用特别任务抓紧工具的种类,一个适当的夹子交换器系统可能是必需的。应该提及一点，它不总是可能使传统的操纵方法适应显微世界的需量。 一个主要的问题是完全地不同于显微世界的各种不同力的效应。万有引力只在显微世界扮演一个较小的角色,但是，诸如静电力和范德华力之类的引力的作用是不容忽视的。 如果湿度是高的或者一个操纵者是潮湿的，液体表面拉力也能在显微操作中担任一个吸引力。这个不寻常的对力的灵敏度在一个显微操作装置中可能是非常影响的。例如, 对机器人来说，抓紧而且操纵一个物件要比后来释放物件容易些。另一方面, 如此的一个黏附力能被用来开发能基本上不同于普通的机械和空气的方法的新的抓紧方法。在叁考文献【1】中,为附着的抓紧提供了一些有趣的想法,像是电荷在一个操纵者或湿的特别微型机械孔的一个夹子表面上。显微操作装置的性能和智力度作为一个手动式是低的; 它通过介入可视操作和进一步的针对一个自动化得到改良; 这和传统的机械手相似。今天大多数的显微操作调查焦点集中在从从纯粹手动到可视操作系统获得的改进【2-4】。如先前提到的,人们正在尽可能现实的将结果从显微世界向操作者进行传输。很重要的是，操作者在他的视域中有整个的现场而且他能见到来自不同角度的工作空间。此外视觉的信息,可能的话 操作者也应该能够接受到声学和力信号; 这可能增加他操作的精确度而且避免破坏微观物质。因为这些，被执行进入微观工具之内的力感知器被需要(举例来说,显微抓爪器)。现在适当的解决方法正在被寻找以实现这种类型的感知器【5】。3. 柔性显微操作装置的发展：典型地，在一个传统的自动机械或半自动式的总成装置中，标准化机械的零件在定义明确的工作位置被装配。通常执行工作的机械手是多桥线臂设计，或者他们是吊架系统,通常被
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