机械类毕业设计外文及其翻译

1、译 文原文题目：State of the art in robotic assembly译文题目： 用机械手装配的发展水平 学 院： 机电工程学院 专业班级： 09级机械工程及自动化01班 学生姓名： 学 号： 大学本科毕业设计（译文）From: State of the art in robotic assemblyRobotic assembly systems offer good perspectives for the rationalization of assembly activities. Various bottlenecks are still encountered,

2、however, in the widespread application of robotic assembly systems. This article focuses on the external developments, bottlenecks and development tendencies in robotic assembly.External developmentsThe current market trends are:Increasing international competition, shorter product life cycle, incre

3、asing product diversity, decreasing product quantity, shorter delivery times, higher delivery reliability, higher quality requirements and increasing labour costs. Next to these market developments, technological developments also play a role, offering new opportunities to optimize price, quality an

4、d delivery time in their mutual relationships. The technological developments are among other things: information technology, new design strategies, new processing techniques, and the availability of flexible production systems, such as industrial robots. Companies will have to adjust their policy t

5、o these market and technology developments (market pull and technology push, respectively). This policy is determined by the company objectives and the company strategy which lie at its basis. Under the influence of the external developments mentioned, the company objectives can, in general, be divi

6、ded into: high flexibility, high productivity, constant and high product quality, short throughput times, and low production costs. Optimizing these competition factors normally results in the generation of more money, and thus (greater) profits. To realize this objective, most companies choose the

7、following strategies: reduction of complexity, application of advanced production technologies, integral approach, quality control, and improvement of the working conditions. Figure 1 shows the company policy in relation to the external developments to which the company policy should be adjusted.Fig

8、ure 1. External developments and company policyWith regard to the product and production development, a subdivision can be made into the following strategies which involve1:The product: design for manufacturing/assembly, a short development time, a more frequent development of new products, function

9、 integration to minimize the number of parts, miniaturization and standardization.The process: improved controllability, shorter cycle times and minimal stocks. There is a trend increasingly to carry out processes in discrete production in flow form.The production system: the use of universal, modul

10、ar, and reliable system components, high system flexibility (in relation to decreasing batch sizes, and increasing product variants), and the integration of product systemsin the entire production.State of the artParts manufacturing and assembly together form coherent sub-processes within the produc

11、tion process. In parts manufacturing, the raw material is processed or transformed into product parts in the course of which the form, sizes and/or properties of the material are changed. In assembly the product parts are put together into subassemblies or into final products. Figure 2 shows the rel

12、ationships between these functional processes and the most important control processes within an industrial enterprise. This shows that assembly by means of material or product flows is linked to parts manufacturing, and that by means of information flows it is integrated with marketing, product pla

13、nning, product development, process planning and production control.Figure 2. Assembly as part of the production processAssembly forms an important link in the whole manufacturing process, because this operational activity is responsible for an important part of the total production costs and the th

14、roughput time. It is one of the most labour-intensive sectors in which the share of the costs of the assembly can amount from 25 to 75 per cent of the total production costs1. Research shows that the share of the labour costs in the assembly in relation to the total manufacturing costs is approximat

15、ely 45 per cent for lorry engines, approximately 55 per cent for machine tools, and approximately 65 per cent for electrical apparatus1. The centre of the cost items moves more and more from the parts manufacturing to the assembly, as automation of the parts manufacturing has been introduced on a la

16、rger scale and more consistently than for the assembly. This is mainly due to the complexity of the assembly process and is also a result of assembly unfriendly product designs. As a result, there are high assembly costs. Furthermore, it appears that assembly accounts for approximately 20 to 50per c

17、ent of the total throughput time1. On the one hand, rationalization and automation of the assembly offer good opportunities to minimize the production costs and the throughput time. However, success depends on numerous factors, such as an integral perception of assembly in conjunction with marketing

18、, product planning, product development, process planning, production control and parts manufacturing (see Figure 2). For this purpose, an assembly-friendly product and process design are of essential importance. Research shows that the design costs of a product amount to only approximately 5 per ce

19、nt of the manufacturing costs on average, and that the product design influences approximately 70 per cent of these costs. Examples are alternative material choice, differently shaped parts, and/or having one part fulfil various functions. On the other hand, rationalization and automation of the ass

20、embly provide the opportunity of taking advantage of external developments, such as increasing product diversity, shorter delivery times, and a shorter product life cycle (see Figure 1).Except for the complexity of the product and process design, the performance of robotic assembly systems is also d

21、etermined by the degree of synchronization between the assembly system and the parts manufacturing, the flexibility of the end-effectors and of the peripheral equipment, as well as by the system configuration. In Japan, most robotic assembly systems have a line configuration in contrast with the sys

22、tems in the USA and Europe. Apart from Europe and the USA, preference is increasingly given to robotic assembly systems in Japan, instead of manual and mechanized systems. The largest area of application of robotic assembly systems in Japan is the electromechanical industry (40 per cent), followed b

23、y the car industry (approximately 27 per cent).Increasingly, robot applications are envisaged for the assembly of complex final products, in several varieties and in low to medium-high production volumes. Research has shown that robotic assembly offers good perspectives in small to medium-size batch

24、 production with annual production volumes between 100,000 and 600,000 product compositions per shift. The production volumes for robotic assembly cells lie between approximately 200 and 620 products per hour, and for robotic assembly lines between approximately 220 and 750 products per hour1.Bottle

25、necksExperience has shown that various bottlenecks still thwart the widespread application of robotic assembly systems. These bottlenecks include: a high complexity of the product and process design, a low quality level of the product parts, as well as product dependence of the peripheral equipment.

26、 From a study in Germany into the automation of the assembly process in 355 companies, it appeared that 40 per cent of the companies had an unsuitable product design, 30 per cent had too complex processing of the parts, and 25 per cent had too complex assembly operations5. This study confirms the im

27、portance of design for assembly(DFA).The second area in which difficulties occur concerns the limited accuracy ofthe product parts which makes the assembly process unnecessarily complex. This problem can be solved by optimizing the machining processes in the parts manufacturing, and a proper synchro

28、nization between the parts manufacturing and the assembly process. The integration of parts manufacture into assembly is also an option.The third area in which difficulties occur involves the robot and the peripheral equipment. The bottlenecks here are:1 Limited acceleration an deceleration of robot

29、s: resulting in reduced speed.2 Insufficient means of integrating complex sensors: on the one hand because of the low reliability of these sensors, and on the other hand because of the closeness of robot controllers; a universal language for robotic assembly systems and a standard interface for robo

30、t controllers are, unfortunately, not yet available.3 Limited flexibility of grippers and other assembly tools: owing to the product-dependence of these assembly means, end-effector change is in general required, for which on average 30 per cent of the cycle time will be needed1.4 Limited flexibilit

31、y of the peripheral equipment: this is generally seen as the main bottleneck. The peripheral equipment is often product-dependent, which affects the system flexibility negatively. In this manner, no justice is done to the high flexibility of the robot.5 Limited reliability of the peripheral equipmen

32、t and the low accessibility of individual system components: these aspects are greatly influenced by the product complexity and the system configuration1.These bottlenecks often result in a higher capital consumption, and a longer cycle time of the assembly system. Insufficient coherence and synchro

33、nization between product, process and system design often lie at the basis of this.Development tendenciesIn the past years, numerous DFA methods have been developed to optimize product design, reducing the complexity of the assembly process and assembly costs4,6. These are based on two principles, n

34、amely: avoiding assembly operations and simplifying assembly operations 1,4,6. Avoiding assembly operations can be realized, among other things, by modular product design, and eliminating parts as a result of function integration. Assembly operations can be simplified, for example, by taking numerou

35、s design rules into account, such as one assembly direction (preferably from top to bottom), the simple feeding, handling and composing of parts, as well as a good accessibility of the assembly location. Figure 3 shows an application for the robotic assembly of gearboxes, with the execution of top t

36、o bottom assembly operations.Figure 3. Robotic assembly of gearboxes (ABB)In the field of the assembly process, there are also new developments occurring. Especially for the assembly friendly composition of parts, new joining methods are being applied, such as:1 adhesive bonding;2 snap fittings. In

37、this manner, a form-closed and force-closed connection can be obtained with small effort;3 insert and outsert techniques. In this respect, metal or plastic parts are moulded together during the injection moulding process.Except for developments in the area of product and process design, new developm

38、ents in the area of robotic assembly systems have emerged under pressure of the bottlenecks mentioned, and under influence of the external developments (see Figure 1). These can be classified as developments which involve the robot, and developments in the area of the peripheral equipment. The devel

39、opments regarding the robot are:1 Kinematic and drive: new configurations, lighter constructions, and new drive systems whichguarantee higher speeds and more accuracy.2 Control: increasingly better controlling and programming facilities, as well as the development of standard interfaces for interact

40、ions with the environment, and for communication with control systems higher in the hierarchy. CAD and simulation systems are also increasingly applied for off-line programming of robotic assembly systems7.3 Sensors: new developments in the area of optical and tactile sensors offer good opportunitie

41、s to increase the controllability of the assembly process.4 End-effectors: new developments in the area of assembly tools and grippers. Especially the integration of optical and tactile sensors, as well as developments in the area of mechanical interfaces, offer in coherence with flexible peripheral

42、 equipment the opportunity to assemble various product families in one system.New developments in the area of the peripheral equipment are:1 Development of programmable feeding systems and magazines, which can be used for more than one type of part.2 Integration of sensors in the peripheral equipmen

43、t for arranging parts and for quality check.3 Increasing miniaturization, universality, and modularity of system components.4 The application of automated guided vehicles (AGVs) as transport system. These developments are particularly initiated by robot manufacturers and technological research insti

44、tutions, whereas from the viewpoint of industrial engineering, there is mainly interest in new strategies for the development of efficient system layouts, enabling various product variants to be assembled cost efficiently in small batches and in low production volumes. The bottlenecks listed and the

45、 development tendencies are summarized in Figure 4.Figure 4. Bottlenecks and developments tendencies in robotic assemblyReferences1. Rampersad, H.K., Integrated and Simultaneous Design for Robotic Assembly, John Wiley, Chichester, November 1994.2. Rampersad, H.K., “A concentric design process”, Adva

46、nced Summer Institute in Co-operative Intelligent Manufacturing Systems, Proceedings of the ASI 94, Patras, Greece, June 1994, pp. 158-65.3. Rampersad, H.K., “Integral and simultaneous design of robotic assembly systems”, paper presented at the Third International Conference on Automation, Robotics

47、and Computer Vision, Singapore, November 1994.4. Boothroyd, G. and Dewhurst, P., Design for Robot Assembly, University of Massachusetts, Armherst, 1985.5. Schraft, R.D. and Baessler, R., “Possibilities to realize assembly-oriented product design”, Proceedings of the 5th International Conference on A

48、ssembly Automation, IFS, Paris, 1984.6. Rampersad, H.K., “The DFA house”, Assembly Automation, Vol. 13 No. 4, December 1993, pp. 29-36.7. Drimmelen, M.J., Rampersad, H.K. and Somers, L.J., “Simulating robotic assembly cells: a general model using coloured petri nets”, Proceedings of the Internationa

49、l conference on Data and Knowledge Systems for Manufacturing and Engineering, Hong Kong, May 1994, pp. 368-82.用机械装配的发展水平机器人装配系统为装配活动提供了合理化良好的发展前景。但是，在机器人装配系统的广泛应用中各种瓶颈依然存在。本文就着眼于说明机器人装配的外部发展瓶颈和发展的趋势。国外发展情况目前市场上的发展趋势是：国际竞争日益加剧，产品生命周期缩短，产品多样性增加，降低产品数量，交货时间缩短，交货的可靠性更高，质量要求更高以及劳动力成本增加。技术的发展也为市场的发展起到了一定的

50、作用，它对优化价格，质量和交货时间的相互关系提供了新的机会。技术发展有其他的东西的发展：信息技术，新的设计战略，新的加工技术和柔性生产系统的可用性，如工业机器人技术的发展。这些市场和技术的发展（市场的拉动和技术推动）将使公司将不得不调整自己的政策。这一政策是在公司目标和战略的基础上确定的。在上述外部发展的影响下，一般来说公司的目标可分为：高弹性，高生产力，不断提高产品质量，吞吐量时间短，生产成本低。优化这些竞争因素通常会赚更多的钱，因此获得（更大的）利润。为了实现这一目标，绝大多数企业选择如下策略：减少复杂性，应用先进的生产技术，整体的方法，质量控制和改善工作条件。图1显示了公司跟上外部发展对

51、公司的发展策略进行调整。国外发展市场发展销售市场国际竞争更短的产品生命周期增加产品多样性降低产品的数量更短的交货时间高可靠的交货更高的质量要求劳动力市场劳动力成本增加缺乏积极进取的合格人员技术的发展产品开发新材料信息技术新设计策略工艺的发展新的连接方法新的制造工艺新工艺策略系统的发展信息技术柔性生产系统：如工业机器人新接口技术公司公司政策公司目标高灵活性生产效率高持续高产品质量短的吞吐量时间生产成本低公司战略降低复杂性 应用先进技术积分方法 质量控制改善劳动环境制造/装配的设计 减少开发时间/成本 更频繁的发展新产品功能集成 小型化 标准化过程改进可控性 缩短周期时间最小化库存生产系统通用性、

52、模块化高可靠性和灵活性整个生产一体化 标准接口产品图1 外部发展和公司政策关于产品和生产的发展，细分可以分为以下策略，包括：产品：制造/装配设计，发展时间短，新产品更频繁的开发，功能集成，减少零件数量，小型化和标准化。方法：可控性的改进，较短的周期时间和最低限度的存货。有越来越多的开展流动离散生产过程的趋势。生产系统：使用通用的、可靠的系统组件，提高系统柔性（相对于减少批量大小，并增加产品的衍生）及产品的整个生产系统的集成。技术发展水平在生产过程中零件的制造和装配在一起，形成连贯的子过程。在零件制造，原材料加工或转化为产品的过程中，产品的形式，尺寸或材料性质会发生变化。在装配产品的零件放在一起

53、成为组件或最终产品。图2显示了这些功能的流程之间的关系,最重要的一个工业企业内部控制流程。这表明，物料或产品流是与零部件的制造息息相关的，信息流是市场营销，产品规划，产品开发集成手段，工艺规划与生产控制的结合。市场营销和产品规划产品开发工艺规划生产控制零部件制造装配信息物料能源产品组件输出产品生产过程预组装结束组装组件1组件和材料组件n输出产品物料进料处理构成特殊工艺检查调整物料输出产品图2 装配生产过程中的一部分组件在整个生产过程中是一个重要环节，因为这种操作活动是负责总的生产成本和生产时间的一个重要组成部分。劳动力最密集的行业之一的装配成本的份额可占总生产成本的25至75。研究表明，组件的

54、总制造成本中的劳动力成本的份额约45为货车发动机，机床的约55，而约65花在电气设备上。零部件制造比装配更加高度自动化，这就使成本中心项目更多的由零部件制造转移到装配。这主要是由于装配过程中的复杂性也因装配困难的产品设计，这就导致了很高的组装成本。此外，组件的装配占约20至50的产品生产时间。一方面，合理、自动化的装配对减少生产成本和生产时间提供了良好的机会。然而，成功取决于许多因素，如一个整体的产品要与组装、营销，产品规划，产品开发，工艺规划，生产控制和零部件制造（参见图2）结合在一起。为了这个目的，工艺设计对一个装配型的产品具有极其重要的意义。研究表明，设计成本只占约5的平均制造成本，然而

55、，设计却对约70的生产成本有影响。例如材料的选择，不同部件形状的不同，和/或一个部件具有各种功能。另一方面，合理化，自动化的装配提供了机会，合理化和自动化的装配对外部发展提供了条件，如增加产品的多样性，更短的交货时间，更短的产品生命周期（见图1）。除了复杂的产品和工艺设计，机器人装配系统的性能也取受到装配系统及零部件制造之间的同步程度，末端执行器和外围设备的灵活性，以及系统配置的影响。在日本,大多数机器人装配系统与美国和欧洲的系统相比有一个线路配置。除了欧洲和美国，日本人越来越偏好于机器人装配系统，代替手工和机械系统。机器人装配系统的应用领域最大的是日本机电工业（40），其次是汽车业（27）。

56、机械手越来越多的设想应用在一些复杂的低中高生产量的产品最终产品的装配。研究表明，机械手装配可以完成年产量100000和600000产品组成，为小到中等规模的批量生产提供了良好的前景。机械手装配单元的生产量是每小时约200和620之间的产品，一条装配线每小时自动装配约220和750之间的产品。经验表明，各种瓶颈仍然阻碍机器人装配系统的广泛应用。这些瓶颈包括：高的产品的复杂性和工艺设计，低质量的产品部件的水平，以及对产品外围设备的依赖。从德国355家自动化的装配工艺公司的一项研究中，就出现了40的公司有不适合的产品设计，30的过于复杂，难以处理，25的有太多复杂的装配操作。这项研究证实了装配设计（

57、DFA）的重要性。第二个领域困难发生涉及有限精度的产品部件,使装配过程不必要的复杂。这个问题可以通过在零部件的制造加工工艺优化及配件的制造和装配过程之间的同步来解决。零件制造为组件的集成也是一个选择。第三领域的困难涉及机器人和外围设备。这里的瓶颈是：1 有限加速减速的机器人：降低速度。2 手段不足：一方面是因为这些传感器可靠性低，另一方面是因为机器人控制器的亲密程度;整合复杂的传感器的机器人装配系统和机器人控制器的标准接口是一种通用的语言，不幸的是，尚未公布。3 有限的灵活性，夹持器和其他组件的工具：由于这些组件的依赖的产品装置，末端执行器的变化通常是必需的，而这要花费在一个周期平均的30的时间。4 外围设备有限的灵活性：这通常被看作是主要的瓶颈。外围设备往往对产品有依赖性，影响了系统的灵活性。在这种方式中，没有调整的机器人的灵活性高。5 有限的可靠性的外围设备和单独的系统组件的低可及性：产品的复杂性和系统配置对这些方面有极大的影响。这些瓶颈往往导致更高的资本消耗，以及更长的循环时间的装配系统。产品，过程和系统设计之间的一致性和同步不足，经常有问题出现。发展趋势在