1、譯 文原文題目：State of the art in robotic assembly譯文題目： 用機械手裝配的發展水平 學 院： 機電工程學院 專業班級： 09級機械工程及自動化01班 學生姓名： 學 號： From: State of the art in robotic assemblyRobotic assembly systems offer good perspectives for the rationalization of assembly activities. Various bottlenecks are still encountered, however, in

2、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, increasing produc

3、t 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 and delivery t

4、ime 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 to these mark

5、et 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 divided into: hi

6、gh 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 following st

7、rategies: 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.Figure 1. Exter

8、nal 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 integration

9、 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, modular, and reli

10、able 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 production process

11、. 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 relationships b

12、etween 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 planning, produ

13、ct 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 throughput tim

14、e. 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 approximately 45 per c

15、ent 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 larger scale a

16、nd 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 cent of the t

17、otal 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, product pl

18、anning, 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 cent of the ma

19、nufacturing 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 assembly provid

20、e 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 determined by

21、 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 systems in the

22、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 by the car in

23、dustry (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 production

24、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.BottlenecksExperie

25、nce 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. From a stud

26、y 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 importance of

27、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 synchronization bet

28、ween 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 robots: resulting

29、 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 robot controller

30、s 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 flexibility of the per

31、ipheral 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 equipment and the lo

32、w 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 synchronization bet

33、ween 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, namely: avoid

34、ing 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 numerous design rul

35、es 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 to bottom ass

36、embly 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 this manner,

37、 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 developments in the

38、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 developments rega

39、rding 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 interactions with th

40、e 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 opportunities to increas

41、e 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 equipment t

42、he 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 equipment for arrang

43、ing 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 institutions, whe

44、reas 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 development

45、 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”, Advanced Summer

46、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 and Computer

47、 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 Assembly Auto

48、mation, 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 International conference

49、 on Data and Knowledge Systems for Manufacturing and Engineering, Hong Kong, May 1994, pp. 368-82.用機械裝配的發展水平機器人裝配系統為裝配活動提供了合理化良好的發展前景。但是，在機器人裝配系統的廣泛應用中各種瓶頸依然存在。本文就著眼于說明機器人裝配的外部發展瓶頸和發展的趨勢。國外發展情況目前市場上的發展趨勢是：國際競爭日益加劇，產品生命周期縮短，產品多樣性增加，降低產品數量，交貨時間縮短，交貨的可靠性更高，質量要求更高以及勞動力成本增加。技術的發展也為市場的發展起到了一定的作用，它對優化價格，質量

50、和交貨時間的相互關系提供了新的機會。技術發展有其他的東西的發展：信息技術，新的設計戰略，新的加工技術和柔性生產系統的可用性，如工業機器人技術的發展。這些市場和技術的發展（市場的拉動和技術推動）將使公司將不得不調整自己的政策。這一政策是在公司目標和戰略的基礎上確定的。在上述外部發展的影響下，一般來說公司的目標可分為：高彈性，高生產力，不斷提高產品質量，吞吐量時間短，生產成本低。優化這些競爭因素通常會賺更多的錢，因此獲得（更大的）利潤。為了實現這一目標，絕大多數企業選擇如下策略：減少復雜性，應用先進的生產技術，整體的方法，質量控制和改善工作條件。圖1顯示了公司跟上外部發展對公司的發展策略進行調整。

51、國外發展市場發展銷售市場國際競爭更短的產品生命周期增加產品多樣性降低產品的數量更短的交貨時間高可靠的交貨更高的質量要求勞動力市場勞動力成本增加缺乏積極進取的合格人員技術的發展產品開發新材料信息技術新設計策略工藝的發展新的連接方法新的制造工藝新工藝策略系統的發展信息技術柔性生產系統：如工業機器人新接口技術公司公司政策公司目標高靈活性生產效率高持續高產品質量短的吞吐量時間生產成本低公司戰略降低復雜性 應用先進技術積分方法 質量控制改善勞動環境制造/裝配的設計 減少開發時間/成本 更頻繁的發展新產品功能集成 小型化 標準化過程改進可控性 縮短周期時間最小化庫存生產系統通用性、模塊化高可靠性和靈活性整

52、個生產一體化 標準接口產品圖1 外部發展和公司政策關于產品和生產的發展，細分可以分為以下策略，包括：產品：制造/裝配設計，發展時間短，新產品更頻繁的開發，功能集成，減少零件數量，小型化和標準化。方法：可控性的改進，較短的周期時間和最低限度的存貨。有越來越多的開展流動離散生產過程的趨勢。生產系統：使用通用的、可靠的系統組件，提高系統柔性（相對于減少批量大小，并增加產品的衍生）及產品的整個生產系統的集成。技術發展水平在生產過程中零件的制造和裝配在一起，形成連貫的子過程。在零件制造，原材料加工或轉化為產品的過程中，產品的形式，尺寸或材料性質會發生變化。在裝配產品的零件放在一起成為組件或最終產品。圖2

53、顯示了這些功能的流程之間的關系,最重要的一個工業企業內部控制流程。這表明，物料或產品流是與零部件的制造息息相關的，信息流是市場營銷，產品規劃，產品開發集成手段，工藝規劃與生產控制的結合。市場營銷和產品規劃產品開發工藝規劃生產控制零部件制造裝配信息物料能源產品組件輸出產品生產過程預組裝結束組裝組件1組件和材料組件n輸出產品物料進料處理構成特殊工藝檢查調整物料輸出產品圖2 裝配生產過程中的一部分組件在整個生產過程中是一個重要環節，因為這種操作活動是負責總的生產成本和生產時間的一個重要組成部分。勞動力最密集的行業之一的裝配成本的份額可占總生產成本的25至75。研究表明，組件的總制造成本中的勞動力成本

54、的份額約45為貨車發動機，機床的約55，而約65花在電氣設備上。零部件制造比裝配更加高度自動化，這就使成本中心項目更多的由零部件制造轉移到裝配。這主要是由于裝配過程中的復雜性也因裝配困難的產品設計，這就導致了很高的組裝成本。此外，組件的裝配占約20至50的產品生產時間。一方面，合理、自動化的裝配對減少生產成本和生產時間提供了良好的機會。然而，成功取決于許多因素，如一個整體的產品要與組裝、營銷，產品規劃，產品開發，工藝規劃，生產控制和零部件制造（參見圖2）結合在一起。為了這個目的，工藝設計對一個裝配型的產品具有極其重要的意義。研究表明，設計成本只占約5的平均制造成本，然而，設計卻對約70的生產成

55、本有影響。例如材料的選擇，不同部件形狀的不同，和/或一個部件具有各種功能。另一方面，合理化，自動化的裝配提供了機會，合理化和自動化的裝配對外部發展提供了條件，如增加產品的多樣性，更短的交貨時間，更短的產品生命周期（見圖1）。除了復雜的產品和工藝設計，機器人裝配系統的性能也取受到裝配系統及零部件制造之間的同步程度，末端執行器和外圍設備的靈活性，以及系統配置的影響。在日本,大多數機器人裝配系統與美國和歐洲的系統相比有一個線路配置。除了歐洲和美國，日本人越來越偏好于機器人裝配系統，代替手工和機械系統。機器人裝配系統的應用領域最大的是日本機電工業（40），其次是汽車業（27）。機械手越來越多的設想應用

56、在一些復雜的低中高生產量的產品最終產品的裝配。研究表明，機械手裝配可以完成年產量100000和600000產品組成，為小到中等規模的批量生產提供了良好的前景。機械手裝配單元的生產量是每小時約200和620之間的產品，一條裝配線每小時自動裝配約220和750之間的產品。經驗表明，各種瓶頸仍然阻礙機器人裝配系統的廣泛應用。這些瓶頸包括：高的產品的復雜性和工藝設計，低質量的產品部件的水平，以及對產品外圍設備的依賴。從德國355家自動化的裝配工藝公司的一項研究中，就出現了40的公司有不適合的產品設計，30的過于復雜，難以處理，25的有太多復雜的裝配操作。這項研究證實了裝配設計（DFA）的重要性。第二個

57、領域困難發生涉及有限精度的產品部件,使裝配過程不必要的復雜。這個問題可以通過在零部件的制造加工工藝優化及配件的制造和裝配過程之間的同步來解決。零件制造為組件的集成也是一個選擇。第三領域的困難涉及機器人和外圍設備。這里的瓶頸是：1 有限加速減速的機器人：降低速度。2 手段不足：一方面是因為這些傳感器可靠性低，另一方面是因為機器人控制器的親密程度;整合復雜的傳感器的機器人裝配系統和機器人控制器的標準接口是一種通用的語言，不幸的是，尚未公布。3 有限的靈活性，夾持器和其他組件的工具：由于這些組件的依賴的產品裝置，末端執行器的變化通常是必需的，而這要花費在一個周期平均的30的時間。4 外圍設備有限的靈活性：這通常被看作是主要的瓶頸。外圍設備往往對產品有依賴性，影響了系統的靈活性。在這種方式中，沒有調整的機器人的靈活性高。5 有限的可靠性的外圍設備和單獨的系統組件的低可及性：產品的復雜性和系統配置對這些方面有極大的影響。這些瓶頸往往導致更高的資本消耗，以及更長的循環時間的裝配系統。產品，過程和系統設計之間的一致性和同步不足，經常有問題出現。發展趨勢在過去的幾年中，眾多的DFA方法已經發展到優化產品設計，減少復雜的裝配工藝和裝配成本。這些都是基于兩個原則，即：避免