焊接机器人的外文文献

焊接机器人的关键技术及研究现状摘要：对智能机器人焊缝跟踪的国内外技术进行了总结，着重介绍了其发展状况和应用，阐述了视觉传感器跟踪、焊缝提取与识别、机器人跟踪控制技术等关键技术，展望了焊接机器人的发展前景。

关键词：焊接机器人；研究现状；焊缝识别跟踪；未来趋势KeytechnologiesandresearchstatusofweldingrobotsAbstract: The domestic and foreign technologies of intelligent robot welding seam tracking are summarized, and its development and application areemphatically introduced. The key technologies such as visual sensor tracking, welding seam extraction and recognition, and robot tracking control technologyare expounded. The development prospect of welding robot is prospected.Key words: welding robot; Research status; Weld identification and tracking; The future trend随着国家的2025智能制造发布实施，越来越多的制造业开始向智能化转型，根据不完全的数据，几乎有一半的[1]工业机器人都是用来生产焊接机器人的，而焊接机器人的历史更悠久，现在已经发展成了各种各样的机器人。

近十年来，计算机、机器视觉和网络技术的飞速发展，使现代科学研究取得了长足的进步。

随着对焊接机器人的深入研究和智能的不断完善，焊接机器人已逐渐能够更好地适应各种复杂的作业环境，并解决了许多实际生产过程中遇到的问题。

(文档含英文原文和中文翻译)中英文资料外文翻译Weld robot application present conditionAccording to incompletely statistics, the whole world about has in the industrial robot of service nearly half of industrial robots is used for multiform weld to process realm, weld robot of application in mainly have two kinds of methods most widespreadly, then order Han and electricity Hu Han.What we say's welding robot is in fact welding to produce realm to replace a welder to be engaged in the industrial robot of welding the task.These weld to have plenty of to design for being a certain to weld a way exclusively in the robot of, but majority ofly weld robot in fact is an in general use industrial robot to pack up a certain weld tool but constitute.In many task environments, a set robot even can complete include weld at inside of grasp a thing, porterage, install, weld, unload to anticipate etc. various tasks, robot can request according to the procedure with task property and automatically replace the tool on the robotwrist, the completion corresponds of task.Therefore, come up to say from a certain meaning, the development history of industrial robot is the development history that welds robot.Know to all, weld to process to request that welder have to have well-trained operation technical ability, abundant fulfillment experience, stability of weld level;It is still a kind of labor condition bad, many smoke and dust, hot the radiation is big, risk Gao of work.The emergence of the industrial robot makes people naturally thought of first the handicraft that replace a person with it welds and eases the welder's labor strength, can also promise to weld quality and exaltation to weld an efficiency at the same time.However, weld again with other industry process process different, for example, electricity Hu Han process in, drive welder piece because of part heat melt with cool off creation transform, the Han sews of the track will therefore take place to change.Handicraft Han the experienced welder can sew position according to the actual Han observed by eyes adjustment Han in good time the position, carriage of the gun and run about of speed to adapt to the variety that the Han sews a track.However the robot want to adapt to this kind of variety, have to the position and status of gun that want to"see" this kind of to change, then adopt homologous measure to adjust Han like person first, follow while carrying out to sew actually to the Han.Because the electricity Hu welds to have in process strong arc light, give or get an electric shock Hu noise, smoke and dust and Rong drop transition unsteady and causable Han silk short circuit, big electric current strong magnetic field etc. complicated environment factor of existence, the robot wants to examine and identifies a withdrawing of the signal characteristic needed for sewing Han and don't seem to be industrial the other in the manufacturing to process the examination of process so easily, therefore, welding the application of robot is to used for to give or get an electric shock the process of Hu Han in the beginning.Actually, industrial robot at welded the application of realm to produce on-line electric resistance to order a Han beginning from the car assemble at the earliest stage.The reason lies in the process that the electric resistance orders Han opposite more simple, control convenient, and not need Han to sew a track follow, to the accuracy of the robot and repeat the control of accuracy have lower request.Order the Han robot assembles to produce a great deal of on-line application to consumedly raise the rate of production that the car assemble welds and weld quality in the car, at the same time again have a gentle characteristics for welding, then want ～only change procedure, can produce in the same on-line carry on assemble to weld to different cars type.BE born till the beginning of this 80's in century from the robot, the robot technique experienced a development process of long term slowness.90's, along with the rapiddevelopment of calculator technique, micro-electronics technique, and network technique...etc., the robot technique is also flown soon a development.The manufacturing level, control speed and control accuracy and dependable sex etc. of industrial robot continuously raises, but manufacturing cost and price of robot continuously descend.Is social in the west, with contrary robot price BE, the person's labor force cost contains the trend to continuously increase.United Nations European Economic Committee(UNECE) statisticses from the variety curve of 1990-2000 years of the robot price index number and labor force cost index number.Among them the robot price of 1990 index number and labor force cost the index number is all reference to be worth 100, go to 2000, labor force cost index number is 140, increased 40%;But robot under the sistuation that consider a quality factor the price index number is lower than 20, lowered 80%, under the sistuation that take no account of a quality factor, the price index number of robot is about 40, lowered 60%.Here, the robot price that takes no account of a quality factor means actual price of the robot of now with compared in the past;And consider that the quality factor means because the robot make the exaltation of craft technique level, manufacturing quality and function of robot even if want also under the condition of equal price compare high before, therefore, if pressed the past robot equaled quality and function to consider, the price index number of robot should be much lower.Can see from here, national in the west, because the exaltation of labor force cost brings not small pressure for business enterprise, but the lowering of robot price index number coincidentally expands application to bring a chance further for it again.Reduce the equipments investment of employee and increment robot, when their expenses attains some one balance point, the benefit of adoption robot obviously wants to compare to adopt the benefit that the artificial brings big, it on the other hand can consumedly raise the automation level of producing the equipments and raise to labor rate of production thus, at the same time again can promote the product quality of business enterprise, raise the whole competition ability of business enterprise.Although robot 1 time invests a little bit greatly, its daily maintenance and consume is more opposite than its to producing far is smaller than completing the artificial expenses that the same task consumes.Therefore, from farsighted see, the production cost of product also consumedly lowers.But the robot price lower to make some small and medium enterprises invest to purchase robot to become easy to accomplish.Therefore, the application of industrial robot is soon flown a development in every trade.According to the UNECE statistics, the whole world has 750,000 in 2001 set the industrial robot is used for industry manufacturing realm, among them 389,000 in Japan, 198,000 in EU, 90,000 in North America, 73,000 at rest nation.Go to at the end of 2004 the whole world to have at least in the industrial robot of service about 1,000,000.Because the robot controls the exaltation of speed and accuracy and particularly give or get an electric shock the development that the Hu spreads a feeling machine to combine to weld in the robot in get an application, make the robot give or get an electric shock the Han of Hu Han to sew a track to follow and control a problem to some extent and get very solution, the robot welds in the car to make the medium application orders Han to soon develop into the car zero from originally more single car assemble partses and electricity Hu within assemble process Han.Robot's giving or getting an electric shock the biggest characteristics of Hu Han is gentle, can immediately pass to weave a distance at any time a change to weld a track and weld sequence, therefore most be applicable to quilt welder piece the species variety is big, the Han sew short but many, product with complicated shape.This at the right moment again characteristics according to car manufacturing.Being the renewal speed of the particularly modern social car style is very quick, adopting the car production line of robot material can nicely adapt to this kind of variety.Moreover, robot's giving or getting an electric shock Hu Han not only used for a car manufacturing industry, but also can used for other manufacturing industries that involve to give or get an electric shock Hu Han, like shipbuilding, motorcycle vehicle, boiler, heavy type machine etc..Therefore, the robot gives or gets an electric shock the application of Hu Han gradually extensive, on the amount greatly have exceed the robot order the power of Han.Along with car reducing in weight manufacturing the technical expansion, some high strong metal alloy materials and light metal alloy material(is like aluminum metal alloy, and magnesium metal alloy...etc.) get an application in the material in the car structure.These materials' welding usually can not solve with the welding of tradition method, have to adopt to lately weld a method and weld a craft.Among them, Gao power laser Han and agitation rub Han etc. to have to develop a potential most .Therefore, robot and Gao power laser Han and agitation rub combining of Han to become inevitable trend.Be like the public in Shanghai to wait domestic to most have the car manufacturer of real strenght in fact at their new car type manufacturing process in have already in great quantities used robot laser to weld.Give or get an electric shock Hu Han to compare with robot, robot laser the Han of the Han sews to follow accuracy to have higher request.According to the general request, the robot gives or gets an electric shock the Han of Hu Han(include GTAW and GMAW) to sew to follow accuracy to control in 1| of the electrode or the Han silk diameter 2 in, at have the condition that fill the silk under the Han sew to follow accuracy to loosen appropriately.But to laser Han, the laser projects light upon the light spot in the work piece surface while welding diameter usually at 0.6 in, is farer small than Han silk diameter(be usually bigger than 1.0), but the laser weld usually and not add to fill Han silk, therefore, the laser is welding if onlythe spot position has a little bit deviation, then will result in to be partial to Han and leak Han.Therefore, the robot laser of the public in Shanghai's car car crest Han in addition to pack in the work tongs up adopt measure to prevent from welding to transform, still just the robot laser Han gun front installed the high accuracy laser of SCOUT company in Germany to spread a feeling machine to used for Han to sew a following of track.The structure form of industrial robot is a lot of, in common usely have right angle to sit mark type, flexible type, and crawl along type...etc. by mark type, many joints by mark type, surface of sphere by mark type, pillar noodles, according to different use still at continuously development in.It is many robots of joint types of the mimicry person's arm function to weld what robot can adopt a different structure form according to the applied situation of dissimilarity, but use at most currently, this because the arm vivid of many joint type robots is the biggest, it can make space position and carriage of Han gun adjust into arbitrarily the status weld by satisfying a demand.Theoretically speak, the joint of robot is many more, the freedom degree is also many more, the joint redundancy degree is big more, and the vivid is good more;But also go against the sitting of kinetics control of marking the transformation and each joint position for robot to bring complexity at the same time.Because weld to usually need in the process with the space right angle sit to mark the Han on the representative work piece to sew position conversion for the Han gun carry the space position and carriage of department and pass robot again go against the kinetics compute a conversion for to the control of robot each joint angle position, but the solution of this transformation process usually isn't unique, the redundancy degree is big, solve more many more.How select by examinations the steady that the quite the cheese solution welds to exercise in the process to the robot very important.Different treatment of system to this problem of the robot control doesn't exert a homology.Is general to come to speak, have 6 controls request of positions and space carriages that the robots of joints basically can satisfy a Han gun, 3 among those freedoms degree(XYZ) space position used for controling a Han gun to carry a department, another 3 freedom degrees(ABC) are used for the space carriage that controls a Han gun.Therefore, currently weld robot majority as 6 joint types.For some weld situation, work piece because of leading big or the space is several what the shape is too complicated, make the Han gun of welding the robot can not arrive appointed Han to sew position or Han gun carriage, have to pass the freedom degree of the way increment robot of increasing 1~3 exterior stalks at this ually have two kinds of way of doings:One is the orbit that the robot Be packed to to move small car or Dragon gate up, the homework space of extension robot;Two is to let the work piece move or turn, make workpiece up of weld the homework space that the part gets into robot.Also have of adopt two kinds of above-mentioned ways at the same time, let the welding of work piece part and robots all be placed in the best weld position.Weld the plait distance of robot method currently still with on-line show and teach a way(Teach-in) is lord, but wove the interface ratio of distance machine to have many improvements in the past, particularly is the adoption of LCD sketch monitor and make and weld the plait distance of the robot interface lately gradually friendly, operation more easy.However robot plait distance Han's sewing the key point on the track to sit to mark position still have to pass to show to teach the way how to obtain, then deposit the sport instruction of procedure.This sews track to some Hans of complicated shapes to say, have to cost a great deal of time to show to teach and lowered the use efficiency of robot thus and also increased the labor strength of weaving the distance personnel.The method that solves currently includes 2 kinds:One is show to teach a plait distance just rough obtain a few Hans to sew a few keys on the track to order, then spread a feeling machine(usually is give or get an electric shock Hu to spread feeling machine or laser sense of vision to spread a feeling machine) through the sense of vision of welding the robot of auto follow the actual Han sew a track.Although this way still cans not get away from to show to teach a plait distance,this way cans ease to show the strength of teaching the plait distance to some extent and raises to weave a distance efficiency.But because of the characteristics of electricity Hu Han, the sense of vision of robot spreads a feeling machine be not sew forms to all apply to all Hans.Two is the way that adopts a completely off-line plait distance, make the robot weld drawing up of procedure and Han to sew a track to sit to mark adjusting of obtaining of position, and procedure to try all to compute in a set to independently complete on board, don't need participation of robot.Robot off-line plait distance as early as several years ago have, just in order to being subjected to restriction of the calculator function at that time, off-line plait distance software with text originally way is lord, wove a distance member to need to acquaint with the all instruction systems and phrasing of robot, also needed to know how made sure that the space position that the Han sews a track sits a mark, therefore, wove a distance work to not and easily save time.Along with exaltation and calculator of the calculator function 3D sketch technical development, present robot off-line plait distance system majority can under the 3D sketch environment movement, the plait distance interface amity, convenience, and, obtaining Han to sew a sitting of track to mark position usually can adopt the way of "conjecture show to teach"(virtual Teach-in), using a mouse to easily click the welding of work piece in the 3D virtual environment the part can immediately the spaceacquiring the sit a mark;In some systems, can sew directly born Han of position to sew a track through the Han that define in advance in the CAD sketch document, then the automatically born robot procedure combines to download robot to control system.Thus and consumedly raised the plait distance of the robot efficiency, also eased the labor strength of weaving the distance member.Currently, it is international to there have been using an off-line plait distance of robot according to the company of common PC machine on the market software.It is like Workspace5, and RobotStudio...etc..Figure 9 show develop by oneself for the writer of according to PC of 3D can see to turn an off-line plait distance of robot system.The system can IRB140 robots aiming at ABB company carry on an off-line plait distance, the Han in the procedure sews a track to pass conjecture to show to teach to acquire, and can let the robot press the track in the procedure to imitate sport in the 3D sketch environment, examine its accuracy and rationality with this.The procedure woven can pass a network directly the download to the robot controller.The industrial robot of our country"75" science and technologies offend a pass to start starting from the 80's, currently already basic control a robot operation of the design manufacturing of the machine technique, control system hardware and software to design technique, kinetics and track to program a technique, gave birth to parts of robot key dollar spare part, develop to spray a paint, Hu Han and order robots, such as Han, assemble and porterage...etc.;The robot of Hu Han has already applied in the Han of car manufactory to pack on-line.But total of come to see, our country of industrial robot technique and it engineering application of level and abroad than still have certain distance, such as:Credibility low outside the country product;The robot application engineering starts a little bit late and apply realm narrow, production line system technique and abroad than have a margin;The applied scale is small, didn't form robot industry.The robot of the current our country the production is all request that applies a door, list door the single time re- design, the species specification is many, small batch quantity, zero partses are in general use to turn degree low, provide a goods period long, the cost is not low either, and the quality, credibility is unsteady.Consequently and urgently need to solve industry to turn an ex- key technique for expecting, Be to the product carry on programing completely, make good series to turn, in general use turn, the mold piece turn a design and actively push forward industry to turn progress.3, weld robot development trendThe international robot boundaries are enlarging a research, carry on robot currently total technical research.The development trend sees from the robot technique, weld robot similar to the other industrial robot, continuously turn to the intelligence and diversify a direction todevelop.Is concrete but talk, performance in as follows a few aspects:1).The robot operates machine structure:Pass a limited dollar the analysis and mold Tai analyze and imitate the usage of true design etc. modern design method and carry out robot operation organization of excellent turn a design.Quest high strength light quality material, raise a load further|hold with dignity a ratio.For example, take Germany's KUKA company as the representative's robot company, have already merged robot the parallelogram structure change to opening chain structure and expand the work scope of robot, the application of light quality aluminum metal alloy material add, consumedly raise the function of robot.The RV that in addition adopts a forerunner decelerates a machine and communicates servo electrical engineering, make robot operation machine almost become don't need support system.The organization facing mold piece turns and can weigh to reach a direction development.For example, the servo electrical engineering in the joint mold piece, decelerate machine and examine system Christian Trinity to turn;From joint mold piece, connect a pole mold piece is constructed robot the whole machine with the reorganization method;The abroad has already had the mold piece the disguise to go together with a robot product to ask city.The structure of the robot is getting clever, control system smaller and smaller, twos just turn a direction development toward the integral whole.The adoption merges organization and makes use of a robot technique, realization Gao accuracy measure and process, this is the robot technique to number control technique of expand, carried out robot and number to control technique integral whole to turn to lay foundation for future.Italian COMAU company, companies like Japan FANUC,etc developed this kind of product.焊接机器人应用现状据不完全统计，全世界在役的工业机器人中大约有将近一半的工业机器人用于各种形式的焊接加工领域，焊接机器人应用中最普遍的主要有两种方式，即点焊和电弧焊。

Title: Working Principle of a Welding MachineA welding machine is a vital tool in various industries, enabling the joining of metal components through the application of heat and pressure. Here’s an explanation of the working principle of a welding machine:1. Electrical Power Source:A welding machine typically operates using electrical power from a mains supply or generator. This power is essential for generating the heat needed to melt the metal pieces being joined.2. Generation of Heat:The welding machine produces heat through various methods, such as electric arcs or resistance heating. In arc welding, for example, an electric arc is created between the welding electrode and the workpiece, generating intense heat at the point of contact.3. Melting of Metal:As the heat is applied to the metal pieces, they reach their melting point, becoming molten and forming a pool of liquid metal. This molten metal serves as a filler material, creating a strong bond between the pieces being welded.4. Formation of Weld Bead:The molten metal from both the electrode and the workpiece forms a weld pool, which solidifies to create a joint known as a weld bead. This weld bead provides the structural integrity needed for the welded components to function as a single unit.5. Control and Regulation:Welding machines often include controls and regulators to adjust parameters such as current, voltage, and welding speed. These settings can be optimized based on the type of metal being welded, the thickness of the materials, and the desired quality of the weld.6. Safety Measures:Welding machines incorporate safety features to protect the operator and surrounding environment from hazards such as electric shock, arc flash, and fumes. These may include protective gear, ventilation systems, and automatic shut-off mechanisms.7. Application of Pressure (Optional):In some welding processes, additional pressure may be applied to the joint to ensure proper bonding and alignment of the metal pieces. This pressure can be exerted mechanically or hydraulically, depending on the welding technique being used.8. Post-Welding Treatment:After the welding process is complete, the welded joint may undergo post-welding treatment such as cooling, cleaning, and inspection. These steps help ensure the integrity and quality of the weld, identifying any defects that may require correction.In summary, a welding machine functions by generating heat, melting the metal pieces, and forming a strong bond between them to create a unified structure. Through precise control and regulation, welding machines enable the fabrication of complex metal assemblies essential in various industrial applications.。

介绍机器人制作过程的英文作文Robotics: The Art of Creating Intelligent Machines.Robotics is an exciting and rapidly evolving field that combines elements of engineering, computer science, and artificial intelligence. The goal of robotics is to create machines that can automate tasks, perform complex operations, and interact with the world around them. The process of building a robot involves a series of steps, from design and programming to testing and deployment.1. Design and Conceptualization.The first step in the robotic creation process is to design the robot's physical structure and determine its functionality. This involves defining the robot's size, shape, and the materials that will be used in its construction. The designer must also consider the robot's intended purpose and the environment in which it will operate.2. Mechanical Engineering.Once the design is complete, the robot's mechanical components must be engineered. This includes designing and building the robot's body, joints, and actuators. The materials used in the robot's construction must becarefully selected to ensure that the robot is strong, durable, and lightweight.3. Electrical Engineering.The next step is to design and implement the robot's electrical systems. This includes the robot's power supply, sensors, and actuators. The robot's electrical system must be designed to be efficient and reliable, and it must be able to withstand the rigors of the robot's intended environment.4. Programming.Once the robot's mechanical and electrical systems arecomplete, the robot must be programmed. The robot's program will dictate how the robot behaves and interacts with its environment. The program must be written in a language that the robot's computer can understand, and it must be carefully tested and debugged to ensure that the robot functions as intended.5. Testing and Deployment.Once the robot is programmed, it must be thoroughly tested to ensure that it meets the design specifications. The robot should be tested in a variety of environments and conditions to ensure that it is robust and reliable. Once the robot has passed all of the necessary tests, it can be deployed for its intended purpose.Conclusion.The process of building a robot is a complex and challenging task, but it is also a rewarding one. By combining the fields of engineering, computer science, and artificial intelligence, robotics engineers are creatingmachines that are capable of performing amazing feats. As the field of robotics continues to evolve, we can expect to see even more incredible robots in the years to come.。

毕业设计（论文）外文文献翻译文献、资料中文题目：机器人文献、资料英文题目：Robots文献、资料来源：文献、资料发表（出版）日期：院（部）：专业：班级：姓名：学号：指导教师：翻译日期：2017.02.14外文翻译外文资料：RobotsFirst, I explain the background robots, robot technology development. It should be said it is a common scientific and technological development of a comprehensive results, for the socio-economic development of a significant impact on a science and technology. It attributed the development of all countries in the Second World War to strengthen the economic input on strengthening the country's economic development. But they also demand the development of the productive forces the inevitable result of human development itself is the inevitable result then with the development of humanity, people constantly discuss the natural process, in understanding and reconstructing the natural process, people need to be able to liberate a slave. So this is the slave people to be able to replace the complex and engaged in heavy manual labor, People do not realize right up to the world's understanding and transformation of this technology as well as people in the development process of an objective need.Robots are three stages of development, in other words, we are accustomed to regarding robots are divided into three categories. is a first-generation robots, also known as teach-type robot, it is through a computer, to control over one of a mechanical degrees of freedom Through teaching and information stored procedures, working hours to read out information, and then issued a directive so the robot can repeat according to the people at that time said the results show this kind of movement again, For example, the car spot welding robots, only to put this spot welding process, after teaching, and it is always a repeat of a work It has the external environment is no perception that the force manipulation of the size of the work piece there does not exist, welding 0S It does not know, then this fact from the first generation robot, it will exist this shortcoming, it in the 20th century, the late 1970s, people started to study the second-generation robot, called Robot with thefeeling that This feeling with the robot is similar in function of a certain feeling, for instance, force and touch, slipping, visual, hearing and who is analogous to that with all kinds of feelings, say in a robot grasping objects, In fact, it can be the size of feeling out, it can through visual, to be able to feel and identify its shape, size, color Grasping an egg, it adopted a acumen, aware of its power and the size of the slide. Third-generation robots, we were a robotics ideal pursued by the most advanced stage, called intelligent robots, So long as tell it what to do, not how to tell it to do, it will be able to complete the campaign, thinking and perception of this man-machine communication function and function Well, this current development or relative is in a smart part of the concept and meaning But the real significance of the integrity of this intelligent robot did not actually exist, but as we continued the development of science and technology, the concept of intelligent increasingly rich, it grows ever wider connotations.Now I have a brief account of China's robot development of the basic profiles. As our country there are many other factors that problem. Our country in robotics research of the 20th century the late 1970s. At that time, we organized at the national, a Japanese industrial automation products exhibition. In this meeting, there are two products, is a CNC machine tools, an industrial robot, this time, our country's many scholars see such a direction, has begun to make a robot research But this time, are basically confined to the theory of phase .Then the real robot research, in 7500 August 5, 1995, 15 nearly 20 years of development, The most rapid development, in 1986 we established a national plan of 863 high-technology development plan, As robot technology will be an important theme of the development of The state has invested nearly Jiganyi funds begun to make a robot, We made the robot in the field quickly and rapid development.At present, units like the CAS ShenYng Institute of Automation, the original machinery, automation of the Ministry, as of Harbin Industrial University, Beijing University of Aeronautics and Astronautics, Qinghua University, Chinese Academy of Sciences, also includes automation of some units, and so on have done a very important study, also made a lot of achievements Meanwhile, in recent years, we end up in college, a lot of flats in robot research, Many graduate students and doctoral。

机器⼈外⽂⽂献翻译、中英⽂翻译外⽂资料robotThe industrial robot is a tool that is used in the manufacturing environment to increase productivity. It can be used to do routine and tedious assembly line jobs，or it can perform jobs that might be hazardous to the human worker . For example ，one of the first industrial robot was used to replace the nuclear fuel rods in nuclear power plants. A human doing this job might be exposed to harmful amounts of radiation. The industrial robot can also operate on the assembly line，putting together small components，such as placing electronic components on a printed circuit board. Thus，the human worker can be relieved of the routine operation of this tedious task. Robots can also be programmed to defuse bombs，to serve the handicapped，and to perform functions in numerous applications in our society.The robot can be thought of as a machine that will move an end-of-tool ，sensor ，and/or gripper to a preprogrammed location. When the robot arrives at this location，it will perform some sort of task .This task could bewelding，sealing，machine loading ，machine unloading，or a host of assembly jobs. Generally，this work can be accomplished without the involvement of a human being，except for programming and for turning the system on and off. The basic terminology of robotic systems is introduced in the following:1. A robot is a reprogrammable ，multifunctional manipulator designed to move parts，material，tool，or special devices through variable programmed motions for the performance of a variety of different task. This basic definition leads to other definitions，presented in the following paragraphs，that give acomplete picture of a robotic system.2. Preprogrammed locations are paths that the robot must follow to accomplish work，At some of these locations，the robot will stop and perform some operation ，such as assembly of parts，spray painting ，or welding .These preprogrammed locations are stored in the robot’s memory and are recalled later for continuousoperation.Furthermore，these preprogrammed locations，as well as other program data，can be changed later as the work requirements change.Thus，with regard to this programming feature，an industrial robot is very much like a computer，where data can be stoned and later recalled and edited.3. The manipulator is the arm of the robot .It allows the robot to bend，reach，and twist.This movement is provided by the manipulator’s axes，also called the degrees of freedom of the robot .A robot can have from 3 to 16 axes.The term degrees of freedom will always relate to the number of axes found on a robot.4. The tooling and frippers are not part the robotic system itself;rather，they are attachments that fit on the end of the robot’s arm. These attachments connected to the end of the robot’s arm allow the robot to lift parts，spot-weld ，paint，arc-weld，drill，deburr，and do a variety of tasks，depending on what is required of the robot.5. The robotic system can control the work cell of the operating robot.The work cell of the robot is the total environment in which the robot must perform itstask.Included within this cell may be the controller ，the robot manipulator ，a work table ，safety features，or a conveyor.All the equipment that is required in order for the robot to do its job is included in the work cell .In addition，signals from outside devices can communicate with the robot to tell the robot when it should parts，pick up parts，or unload parts to a conveyor.The robotic system has three basic components: the manipulator，the controller，and the power source.A.ManipulatorThe manipulator ，which does the physical work of the robotic system，consists of two sections:the mechanical section and the attached appendage.The manipulator also has a base to which the appendages are attached.Fig.1 illustrates the connectionof the base and the appendage of a robot.图1.Basic components of a robot’s manipulatorThe base of the manipulator is usually fixed to the floor of the work area. Sometimes，though，the base may be movable. In this case，the base is attached to either a rail or a track，allowing the manipulator to be moved from one location to anther.As mentioned previously ，the appendage extends from the base of the robot. The appendage is the arm of the robot. It can be either a straight ，movable arm or a jointed arm. The jointed arm is also known as an articulated arm.The appendages of the robot manipulator give the manipulator its various axes of motion. These axes are attached to a fixed base ，which，in turn，is secured to a mounting. This mounting ensures that the manipulator will in one location.At the end of the arm ，a wrist（see Fig 2）is connected. The wrist is made up of additional axes and a wrist flange. The wrist flange allows the robot user to connect different tooling to the wrist for different jobs.图2.Elements of a work cell from the topThe manipulator’s axes allow it to perform work within a certain area. The area is called the work cell of the robot ，and its size corresponds to the size of the manipulator.（Fid2）illustrates the work cell of a typical assembly ro bot.As the robot’s physical size increases，the size of the work cell must also increase.The movement of the manipulator is controlled by actuator，or drive systems.The actuator，or drive systems，allows the various axes to move within the work cell. The drive system can use electric，hydraulic，or pneumatic power.The energy developed by the drive system is converted to mechanical power by various mechanical power systems.The drive systems are coupled through mechanical linkages.These linkages，in turn，drive the different axes of the robot.The mechanical linkages may be composed of chain，gear，and ball screws.B.ControllerThe controller in the robotic system is the heart of the operation .The controller stores preprogrammed information for later recall，controls peripheral devices，and communicates with computers within the plant for constant updates in production. The controller is used to control the robot manipulator’s movements as well as to control peripheral components within the work cell. The user can program the movements of the manipulator into the controller through the use of a hard-held teach pendant.This information is stored in the memory of the controller for later recall.The controller stores all program data for the robotic system.It can store several differentprograms，and any of these programs can be edited.The controller is also required to communicate with peripheral equipment within the work cell. For example，the controller has an input line that identifies when a machining operation is completed.When the machine cycle is completed，the input line turn on telling the controller to position the manipulator so that it can pick up the finished part.Then ，a new part is picked up by the manipulator and placed into the machine.Next，the controller signals the machine to start operation.The controller can be made from mechanically operated drums that step through a sequence of events.This type of controller operates with a very simple robotic system.The controllers found on the majority of robotic systems are more complex devices and represent state-of-the-art eletronoics.That is，they are microprocessor-operated.these microprocessors are either 8-bit，16-bit，or 32-bit processors.this power allows the controller to be very flexible in its operation.The controller can send electric signals over communication lines that allow it to talk with the various axes of the manipulator. This two-way communication between the robot manipulator and the controller maintains a constant update of the end the operation of the system.The controller also controls any tooling placed on the end of the robot’s wrist.The controller also has the job of communicating with the different plant computers. The communication link establishes the robot as part a computer-assisted manufacturing （CAM）system.As the basic definition stated，the robot is a reprogrammable，multifunctional manipulator.Therefore，the controller must contain some of memory stage. The microprocessor-based systems operates in conjunction with solid-state devices.These memory devices may be magnetic bubbles，random-access memory，floppy disks，or magnetic tape.Each memory storage device stores program information fir or for editing.C.power supplyThe power supply is the unit that supplies power to the controller and the manipulator. The type of power are delivered to the robotic system. One type of power is the AC power for operation of the controller. The other type of power isused for driving the various axes of the manipulator. For example，if the robot manipulator is controlled by hydraulic or pneumatic drives，control signals are sent to these devices causing motion of the robot.For each robotic system，power is required to operate the manipulator .This power can be developed from either a hydraulic power source，a pneumatic power source，or an electric power source.There power sources are part of the total components of the robotic work cell.中⽂翻译机器⼈⼯业机器⼈是在⽣产环境中⽤以提⾼⽣产效率的⼯具，它能做常规乏味的装配线⼯作，或能做那些对于⼯⼈来说是危险的⼯作，例如，第⼀代⼯业机器⼈是⽤来在核电站中更换核燃料棒，如果⼈去做这项⼯作，将会遭受有害放射线的辐射。

工业机器人外文参考文献工业机器人外文参考文献1. Gao, Y., & Chen, J. (2018). Review of industrial robots for advanced manufacturing systems. Journal of Manufacturing Systems, 48, 144-156.2. Karaman, M., & Frazzoli, E. (2011). Sampling-based algorithms for optimal motion planning. The International Journal of Robotics Research, 30(7), 846-894.3. Khatib, O. (1986). Real-time obstacle avoidance for manipulators and mobile robots. The International Journal of Robotics Research, 5(1), 90-98.4. Lee, J. H., & Kim, E. B. (2019). Energy-efficient path planning for industrial robots considering joint dynamics. Journal of Mechanical Science and Technology, 33(3),1343-1351.5. Li, D., Li, Y., Wang, X., & Li, H. (2019). Design and implementation of a humanoid robot with flexible manipulators. Robotica, 37(12), 2008-2025.6. Liu, Y., Ren, X., & Wang, T. (2019). A novel adaptive fuzzy sliding mode control for a nonholonomic mobile robot. Soft Computing, 23(3), 1197-1209.7. Loh, A. P., & Tan, K. K. (2014). Vision-based controlof industrial robots using an adaptive neural network. Robotics and Computer-Integrated Manufacturing, 30(2), 177-184.8. Niemeyer, G., & Slotine, J. J. (1990). Stable adaptive teleoperation. The International Journal of Robotics Research, 9(1), 85-98.9. Park, J. Y., & Cho, C. H. (2018). Optimal path planning for industrial robots using a hybrid genetic algorithm. International Journal of Precision Engineering and Manufacturing, 19(5), 755-761.10. Wang, Z., Wang, X., & Liu, Y. (2019). Design and analysis of a novel humanoid robot with intelligent control. International Journal of Advanced Manufacturing Technology, 102(5-8), 1391-1403.。

Welding RobotChapter 1 IntroductionThe gas tungsten arc welding (GTAW) process is based on the electric arc established between a non-consumable electrode of tungsten and the work-pieces to be joined. Part of the heat generated by the electric arc is added to the workpieces, promoting the formation of a weld pool. The weld pool is protected from air contamination by a stream of an inert gas (Ar or He) or a mixture of gases.1．1．1 IntroductionThis process is also known as tungsten inert gas (TIG), although small amounts of non-inert gases may be used in the shielding mixture, such as hydrogen or nitrogen. Autogenous GTAW welding (without filler metal) is used in thin square edged sections (2mm), while V and X type edge preparations are needed in thicker sections. In this case, the addition of filler metal is necessary. This process is extensively used for welding thin components of stainless steel, aluminum, magnesium or titanium alloys as well pieces of carbon and low alloy steels. Heat input in GTAW does not depend on the filler material rate. Consequently, the process allows a precise control of heat addiction and the production of superior quality welds, with low distortion and free of spatter. It is less economical than other consumable electrode arc welding processes, due to its lower deposition rate, and it is sensitive to windy environment because of the difficulty in shielding the weld pool. Besides it shows low tolerance to contaminants on filler or base metals.1．1．2 Welding EquipmentIn this section the relevant aspects related to the welding equipment used with the GATW process will be reviewed, with the objective of exploring the implications for automatic robotic welding.1．1．3 Power SourcesPower sources for GTAW are generally of the constant current type with drooping volt-ampere static curves, Light weight transistorized direct current power sources are currently used, being more stable and versatile than the old thyristor-controlled units . In rectifier-inverter power sources the incoming AC current is rectified and then converted into AC current at a higher frequency than that of the mains supply, in the inverter. Afterwards high voltage AC current is transformed into low voltage AC current suitable for welding, in the transformer, and then rectified, The aim to increase the current frequency is to reduce the weight of the transformer and other components of the source such asinductors and capacitors.1．1．4 Welding TorchThe welding torch holds the non-consumable electrode, assures the transfer of current to the electrode and the flow of shielding gas to the weld pool. Torches with welding regimes up to 200 A are generally gas-cooled and those with continuous operation between 200 and 500 A are water-cooled.1．1．5 Non-consumable ElectrodesNon-consumable electrodes are composed of pure tungsten or of tungsten alloys. Pure tungsten electrodes can be used with DC but are more sensitive to contamination, have lower service life-cycle and exhibit higher tip deterioration than alloyed electrodes. These electrodes can be used in welding of aluminum and magnesium alloys on AC. Thoriated tungsten (2% ThO2) electrodes are widely used in industrial applications due to its excellent resistance to contamination, easy arc starting and stable electric arc. Concerns about safety, because thorium oxide is radioactive, led to the development of other electrodes containing small proportions (around 2%) of simple earth rare elements such as lanthanum, yttrium and cerium or even mixtures of several elements . These electrodes have better operational characteristics than thoriated electrodes and can be used in welding carbon and stainless steels,nickel and titanium alloys. Zirconiated tungsten electrodes are excellent for AC due to its good arc starting, high resistance to contamination and small tip shape deterioration.1．1．6 Arc Striking TechniquesArc initiation by touch striking was used formerly in manual GTAW, but this technique is very sensitive to tungsten contamination, adversely affecting the service life of the electrode. High-frequency-high-voltage (e.g. 3 kV at 5 MHz) supplies are currently used in arc striking and AC arc stabilization in manual GTAW systems. This arc starting technique usually produces interference in electronic equipment in the vicinity of the power source. Programmed touch striking is an alternative technique developed for automatic systems. In this technique current and voltage are limited when electrode touches in the work-piece, in order to prevent electrode contamination. A pilot arc starting can also be used to initiate the main electric arc, though a more complex torch is needed.1．1．7 Shielding Gas RegulatorThe regulator is a device that reduces source gas pressure to a constant working pressure, independently of source pressure variations. Pressure reduction can be made in one or two stages. Regulators in two stages give in general more stable output flow. 1．2 Process ParametersIn this section the relevant parameters for the GTAW process will be reviewed with the double objective of presenting them and showing that they can certainly be used for automatic robotic welding.1．2．1 CurrentCurrent has direct influence on weld bead shape, on welding speed and quality of the weld. Most GTAW welds employ direct current on electrode negative (DCEN) (straight polarity) because it produces higher weld penetration depth and higher travel speed than on electrode positive (DCEP) (reverse polarity). Besides, reverse polarity produces rapid heating and degradation of the electrode tip, because anode is more heated than cathode in gas tungsten electric arc. Reverse polarity may be of interest in welding aluminum alloys because of the catholic cleaning action of negative pole in the work-piece, that is the removal of the refractory aluminum oxide layer. However alternating current is better adapted to welding of aluminum and magnesium alloys, because it allows balancing electrode heating and work-piece cleaning effects. Weld penetration depth obtained with AC is between depth obtained with DCEN and DCEP.1．2．2 Welding SpeedThe effect of increasing the welding speed for the same current and voltage is to reduce the heat input. The welding speed does not influence the electromagnetic force and the arc pressure because they are dependent on the current. The weld speed increase produces a decrease in the weld cross section area, and consequently penetration depth (D) and weld width (W) also decrease, but the D/W ratio has a weak dependence on travel speed. These results suggest that the travel speed does not influence the mechanisms involved in the weld pool formation, it only influences the volume of melted material. Normal welding speeds are from 100 to 500 mm/min depending on current, material type and plate thickness.1．2．3 Arc LengthThe arc length is the distance between the electrode tip and the work-piece. The arc length in GTAW is usually from 2 to 5 mm. If the arc length increases, the voltage to maintain the arc stability must increase, but the heat input to work-piece decreases due to radiation losses from the column of the arc. Consequently, weld penetration and cross section area of melted material decrease with increasing arc length.1．2．4 Shielding GasesShielding gases are used in GTAW in order to prevent atmospheric contamination of the weld metal. This contamination can produce porosity, weld cracking, scaling and evenchange in the chemical composition of melted material. Besides shielding gas also has a large influence on the stability of the electric arc. Gases with low ionization potential facilitate the ignition of the electric arc and those with low thermal conductivity tend to increase the arc stability. Argon is the most used GTAW shielding gas. It has low ionization potential and is heavier than air, providing an excellent shielding of the molten weld pool. Furthermore it is less expensive than helium, the other inert shielding gas used in the process. Argon is used in welding of carbon and stainless steels and low thickness aluminum alloys components. For welding thick aluminum work-pieces and other high-conductive materials, such as copper alloys, helium is recommended because it has higher ionization potential than argon, needing higher voltage for arc initiation and maintenance, but producing higher heat-input. Helium or helium/argon (30-80% He) mixtures allow increased welding speed and improved process tolerance. Mixtures of argon with up to 5% of hydrogen are frequently used in welding of austenitic stainless steels. Hydrogen increases arc-voltage and consequently heat input, increasing weld penetration and weld travel speed, as well improving weld appearance. Argon/hydrogen mixtures are also used in welding of copper nickel alloys. Argon is also used as back side shielding gas, mainly in welding of stainless steels, aluminum alloys and reactive metals.Flow rates of shielding gases depend on weld thickness, being 4-10 l/min for argon and 10-15 l/min for helium, because it is lighter than argon, and consequently less effective in shielding. Gases with a purity of 99.995% are used in welding most of the metals, though reactive materials such as titanium need contaminant level less than 50 ppm.1．2．5 Filler MetalsFiller metals are generally used for plate thickness above 2 mm, having chemical composition similar to that of the parent material. Filler metal diameter is between 1.6 and 3.2 mm and in automatic systems is normally added cold from a roll or a coil.1．2．6 Electrode Vertex AngleThe non-consumable electrode angle influences the weld penetration depth and the weld shape. Electrode angles between 30o and 120o are used. Small angles increase arc pressure and penetration depth but have high tip shape deterioration. Electrode angles from 60o to 120o maintain tip shape for longer periods and give welds with adequate penetration depth-to-width ratio.1．2．7 Cast-to-cast VariationCast-to-cast variation refers to variation observed in penetration of welds produced in the same welding conditions in several batches of austenitic stainless steel with nominallyidentical composition. These changes in the weld bead shape are attributed to variation in proportion of trace elements in the material, such as sculpture, calcium and oxygen. Variations in trace elements seem to affect surface tension and metal flow into the pool . Weld pool shape is also affected by electromagnetic forces, arc pressure and thermo capillarity forces. To minimize this problem several strategies have been adopted such as the use of higher currents or of pulsed current, the application of adequate shielding gases or the application on plate surface of flux coatings containing active ingredients.1．3 Process VariantsGTAW is regarded as a high quality process for welding thin metals using low travel speed and low electrode deposition rate, requiring highly skilled personnel in manual welding. Variants developed seek to improve productivity, mainly deposition rate, penetration depth and welding speed. These variants are implemented in automatic or robotic systems. Hot-wire GTAW is a variant where a heated filler wire is fed to the rear of the melted weld pool at a constant rate.Filler wire is resistance heated close to melting point using mainly AC power sources, in order to minimize magnetic disturbance of the electric arc. Deposition rates up to 14 kg/h can be attained with this process. It has been used in heavy wall fabrication, maintaining high joint integrity .The use of a dual-shielding GTAW technique, where an additional concentric gas shield gives an increase in constriction and stiffness of the electric arc, may be used to increase welding speed and penetration depth .Constriction of the arc is produced by the external cold gas flow which decreases temperature of the outer part of the arc, decreasing the arc cross section where current flow occurs, consequently increasing current density and temperature. Electrode gas and annular gas may be of the same or of different compositions, such as Argon plus 5% hydrogen for internal gas and argon for external gas when welding austenitic stainless steels. This technique also tends to increase the risk of undercut. Very high currents (I > 300 A) may also be used in a conventional automated GTAW process to increase the penetration depth, but defects may form and the process becomes unstable above 500 A. The key hole mode gas tungsten arc welding process, which was developed a few years ago, seems to be suitable for ferrous and non-ferrous materials in the range from 3 to 12 mm. However, this key whole technique is extremely sensitive to arc voltage, and loss of material may occur through the keyhole vent.。

Journal of Materials Processing Technology180(2006)216–220Studies on softening of heat-affected zone of pulsed-currentGMA welded Al–Zn–Mg alloyGaofeng Fu∗,Fuquan Tian,Hong WangSchool of Materials and Metallurgy,Northeastern University,Shenyang110004,ChinaReceived15December2005;received in revised form9June2006;accepted12June2006AbstractStudies on the softening behavior of the7005alloy by means of real welding experiments and heat-affected zone(HAZ)simulation have been conducted.Softening in the HAZ is found to occur above a peak temperature of about200◦C.It was found that the heat-affected zone of the alloys can be divided into two sub-zones according to their different mechanism of softening:the dissolution zone and the overageing zone.The dissolution zone is characterised by dissolution of precipitates and covers the peak temperature range above380◦C.The overageing zone is characterised by growth of precipitates and covers the peak temperature range between230and380◦C.The hardness in the heat-affected zone can be recovered by post-weld heat treatment,especially in the dissolution zone.Artificial ageing is more effective than natural ageing considering the recovery of the hardness.©2006Elsevier B.V.All rights reserved.Keywords:Aluminum alloys;Heat-affected zone;Softening;Welding;Thermal simulation1.IntroductionThe Al–Zn–Mg alloy has wide acceptance in fabrication of lightweight structures requiring a high strength-to-weight ratio, such as storage tanks of space rockets,transportable bridge gird-ers and railway transport systems[1–3].Within the Al–Zn–Mg alloy system the7005alloy is a medium-strength and weldable alloy which contains mainly 4.5%Zn,1.4%Mg and some amounts of manganese.The precip-itation sequence usually proposed for alloys with similar Zn and Mg contents to those of the7005alloy is[4]:α-supersaturated solid solution(␣-SSS),spherical Guinier–Preston(GP)zones, the transition phase(␩ phase)and the intermetallic compound (␩phase).␣-SSS is retained after quenching to room tempera-ture(RT).Thefirst stage of decomposition occurs by aging at RT for a few days(natural aging),which results in the forma-tion of GP zones.The GP zones and the transition phase(␩ ), in the form of semi-coherent precipitates,are primarily respon-sible for hardening of the alloys.The intermetallic compound␩is non-coherent precipitates.It is formed either by growth of the transition phase or by direct precipitation from the solid solu-tion at high temperature and does not contribute to the hardening effect of the alloys[5–7].∗Corresponding author.Tel.:+862483681325;fax:+862423906316.E-mail address:f137********@(G.Fu).In any structural application of this alloy consideration of its weldability is of utmost importance as welding is largely used for joining of structural components.During welding,different microstructural changes are likely to occur in the heat-affected zone(HAZ)of the weld,such as recrystallisation,grain growth and modifications of precipitates.With respect to strength,grain growth plays an important role in the case of non-heat-treatable aluminium alloys,but is of minor importance in the case of heat-treatable aluminium alloys.In the case of heat-treatable aluminium alloys,the strength is mainly influenced by modifi-cation of precipitates[8–10].Although the general transformation behaviour of Al–Zn–Mg alloys is known,detailed knowledge about HAZ softening in some individual alloys is lacking.The purpose of this paper is to obtain fundamental insight in the HAZ softening characteristics of the7005alloy during pulsed-current GMA welding,and to find out how the softening is affected by heat input and post-weld heat treatment.2.Materials and experimental procedure2.1.MaterialsThe base material used in this study is7005alloy in the form of12-mm thick plates in T6condition.The chemical composi-tions of the material are(in wt.%):Al–4.5Zn–1.4Mg–0.4Mn,0924-0136/$–see front matter©2006Elsevier B.V.All rights reserved. doi:10.1016/j.jmatprotec.2006.06.008G.Fu et al./Journal of Materials Processing Technology 180(2006)216–220217Table 1Welding parametersLow heat input conditionsHigh heat input conditions Arc voltage (V)2525Arc current (A)200200Travel speed (cm/min)6030Shielding gasArgon Argon Gas flow rate (l/min)1414Filler wire,diameter (mm)ER5356,1.2ER5356,1.2PolarityDCEP DCEP Process efficiency (%)6565Heat input (J/mm)5001000also containing 0.2Cr,0.02Ti,Fe <0.4,Si <0.35and Cu <0.1.The specimens were machined from the as-extruded 7005bars.2.2.HAZ simulationHAZ simulation was carried out by imposing thermal cycles on a series of small specimens,having dimensions 10mm ×10mm ×60mm.The specimens were machined from the plate material,the longest dimension parallel to the rolling direction of the plate.Two sets of welding conditions were selected for simulation,corresponding to heat inputs of 500and 1000J/mm,respectively (Table 1).The HAZs in the case of both heat inputs were simulated by thermal cycles with peak temperatures between 150and 600◦C,which for the given heat input represent specific locations in the HAZ.The thermal cycles used in the HAZ simulation were calculated with the modified Rosenthal model for two-dimensional heat flow.The properties of the HAZ are usually expressed either as a function of peak temperature or as a function of distance from the fusion boundary.In view of this,it is convenient to know the relation between the peak temperature and the distance from the fusion boundary.This relation was determined for the two heat inputs used in this work (500and 1000J/mm).The results are shown in Fig.1.Fig.1.The relation between peak temperature and the distance from the fusion boundary for two heat inputs (500and 1000J/mm).2.3.Welding experimentsTo be able to compare the results obtained in the case of sim-ulation with the results obtained in the case of real welding,a number of single V-butt welds were made in 12-mm thick plates,using the same welding conditions as those used to calculate the thermal simulation cycles (Table 1).Welding was carried out in a direction normal to the rolling direction of the plate,using a mechanized pulsed-current GMA welding system.Before weld-ing the surface of the workpiece was cleaned by a stainless steel brush in order to remove the oxide layer.2.4.Heat treatmentIn order to examine the influence of heat treatment on the microstructure and properties of the materials,the simulated and welded specimens were subjected to one of the following heat treatments:1.natural ageing (4months at room temperature);2.artificial ageing (24h at 120◦C);3.step ageing (8h at 100◦C +24h at 150◦C).2.5.Examination of hardness and microstructureHardness measurements of both the simulated and welded specimens were carried out using a Vickers hardness machine (5kg load).To study the microstructure of the simulated and welded specimens cross-sections were made,which were subsequently ground and etched using Keller solution.The microstructure was primarily examined by means of optical microscopy (Neophot II).Additionally,transmission electron microscopy (TEM)was carried out using a Philips EM400.The thin foils required for the TEM examination were prepared by jet polishing.3.Results and discussion 3.1.Softening of the HAZIn order to determine the effect of welding on the hardness of the 7005alloy,specimens were simulated and examined follow-ing the procedure described in the previous section.In Fig.2the hardness of the alloys immediately after simulation is plotted as a function of the peak temperature for the situation correspond-ing with a heat input of 500J/mm.The figure shows that softening occurs when the peak tem-perature is higher than about 200◦C,which is equivalent with softening in a zone having a width of about 12mm adjacent to the fusion boundary.As already mentioned above,softening of the HAZ in heat-treatable aluminium alloys is directly related to modification of precipitates.3.2.Modification of precipitatesTo be able to obtain additional information about the pre-cipitation behaviour of the alloys due to welding,transmission218G.Fu et al./Journal of Materials Processing Technology 180(2006)216–220Fig.2.Hardness as a function of peak temperature of simulated specimens directly after simulation (heat input 500J/mm).electron microscopy (TEM)was carried out on both as-received and simulated specimens.Fig.3shows TEM micrographs of 7005specimens simulated at different peak temperatures.In Fig.3(a)the microstructure of the non-simulated parent metal is shown in which small precipitates are visible.During sim-ulation up to a peak temperature of 200◦C the precipitates remain virtually unchanged (Fig.3(b)).However,simulation at a peak temperature of 300◦C,leads to dissolution and growth of precipitates (Fig.3(c)).When the peak temperature exceeds 400◦C,all precipitates are dissolved (Fig.3(d)).On the basis of these observations it may be concluded that the loss of hardness in the HAZ is due to dissolution and/or growth ofprecipitates.Fig.4.Hardness as a function of peak temperature of simulated specimens of 7005alloy for two welding conditions.After simulation,the specimens were treated by artificial ageing.To separate the softening effect due to dissolution from that due to the growth of precipitates,simulated specimens were given an artificial ageing treatment.The idea behind this approach is that dissolved precipitates will be re-formed to hardening precipitates by ageing.The hardness after arti-ficial ageing is plotted as a function of peak temperature in Fig.4.In Fig.4,it can be seen that at temperatures above about 380◦C the hardness is fully recovered to the level of the parent metal by the ageing treatment.Apparently,hardening precipi-tates are formed from the solid solution under these conditions.In the temperature range between about 230and 380◦CtheFig.3.TEM micrographs of simulated specimens directly after simulation:(a)parent metal,(b)peak temperature 200◦C,(c)peak temperature 300◦C and (d)peak temperature 400◦C.G.Fu et al./Journal of Materials Processing Technology 180(2006)216–220219hardness is only partially recovered,which indicates that in this temperature range overageing (growth of precipitates)takes place.The most severe overageing occurs at peak temperatures around 320◦C.It should be noted that for both heat inputs over-ageing occurs within approximately the same peak temperature range,230–380◦C,and that the most severe overageing occurs at the same peak temperature (about 320◦C).On the basis of the foregoing observations,it is possible to divide the HAZ into two sub-zones:the dissolution zone and the overageing zone.The boundary between the two sub-zones corresponds with a peak temperature of about 380◦C.The results obtained on the 7005alloy show that the heat input does not have a measurable influence on the location and size of the sub-zones,but significantly affects the magnitude of overageing.In order to find out at which peak temperature the precipi-tates of the parent metal will be completely dissolved,specimens were simulated at high peak temperatures,cooled down at fast cooling rate to avoid the possible influence of harmful precipita-tion,and artificially aged.After this treatment the hardness was measured.It was found that complete recovery of the hardness occurs at peak temperatures higher than 380◦C.This implies that the temperature which divides the dissolution zone and the overageing zone is 380◦C for the 7005alloy.3.3.Influence of post-weld heat treatmentAs pointed out in the previous section,part of the hardness loss in the HAZ can be recovered by an ageing treatment.In order to sort out the effect of ageing in more detail the hard-ness of the simulated HAZ was measured after different ageing treatments.In Fig.5the hardness of the simulated HAZ is plotted as a function of the distance from the fusion boundary for different heat treatment conditions.Generally speaking,artificial ageing and step ageing result in the best hardness recovery in the high peak temperature area (close to the fusion boundary).It appears that the possibility of property recovery through natural ageing is limited compared with the other two artificial ageing treatments.Even after 4months the hardness oftheFig.5.Hardness as a function of the distance from the fusion line for specimens simulated with fast cooling rate followed by artificialageing.Fig.6.Hardness profiles of simulated and welded material (low heat input con-ditions).naturally aged specimen still has not reached the level obtained by artificial ageing.As can be seen,step ageing leads to some overageing of the unaffected zone,which is presumably due to the relatively high ageing temperature during the last step of this treatment.3.4.Verification of HAZ simulationTo be able to compare the results obtained by means of simulation with the results obtained by real welding,a series of GMA welding experiments was carried out under identical thermal conditions (Table 1).In Fig.6the hardness profiles of both the simulated and the welded material are presented (low heat input conditions).It appears that excellent agreement exists between the results of simulation and the results of real weld-ing,which can be considered as a justification of the simulation approach.4.Conclusions•The HAZ of the 7005alloys can be divided into two sub-zones according to their different mechanism of softening:the dissolution zone and the overageing zone.•The dissolution zone is characterised by dissolution of precipitates and covers the peak temperature range above 380◦C.•The overageing zone is characterised by growth of precipi-tates and covers the peak temperature range between 230and 380◦C.•HAZ hardness can be recovered by post-weld heat treatment.Artificial ageing is more effective than natural ageing consid-ering the recovery of the hardness.References[1]M.P.Wang,Z.W.Wang,Z.N.Wang,L.Zhou,Chin.J.Nonferrous Met.11(6)(2001)1069(in Chinese).[2]S.Sasabe,J.Light Met.Weld.Construct.40(2002)445.[3]P.Allais,P.Mercher,Met.Mater.8(1972)343.[4]R.Ferragut,A.Somoza,A.Tolley,I.Torriani,J.Mater.Process.Technol.141(1)(2003)35.220G.Fu et al./Journal of Materials Processing Technology180(2006)216–220[5]M.Kanno,l.Araki,Q.Cui,Mater.Sci.Technol.10(7)(1994)599.[6]H.M.Hussain,P.K.Ghosh,P.C.Gupta,N.B.Potluri,Weld.J.75(7)(1996)209.[7]M.Iqbal,M.A.Shaikh,M.Ahmad,K.A.Shoaib,J.Mater.Sci.Technol.16(3)(2000)319.[8]T.Ma,G.den Ouden,Int.J.Joining Mater.8(3)(1996)105.[9]H.M.Hussain,P.K.Ghosh,P.C.Gupta,P.N.Babu,Int.J.Joining Mater.9(2)(1997)74.[10]Nicolas,Myriam,Deschamps,Alexis,Mater.Sci.Forum396–402(2002)1561.。

外文原文Introduction to Industrial RobotsIndustrial robets became a reality in the early 1960’s when Joseph Engelberger and George Devol teamed up to form a robotics company they called “Unimation”.Engelberger and Devol were not the first to dream of machines that could perform the unskilled, repetitive jobs in manufacturing. The first use of the word “robots” was by the Czechoslovakian philosopher and playwright Karel Capek in his play R.U.R.(Rossum’s Universal Robot). The word “robot” in Czech means “worker” or “slave.” The play was written in 1922.In Capek’s play , Rossum and his son discover the chemical formula for artificial protoplasm. Protoplasm forms the very basis of life.With their compound,Rossum and his son set out to make a robot.Rossum and his son spend 20 years forming the protoplasm into a robot. After 20 years the Rossums look at what they have created and say, “It’s absurd to spend twenty years making a man if we can’t make him quicker than nature, you might as w ell shut up shop.”The young Rossum goes back to work eliminating organs he considers unnecessary for the ideal worker. The young Rossum says, “A man is something that feels happy , plays piano ,likes going for a walk, and in fact wants to do a whole lot of things that are unnecessary … but a working machine must not play piano, must not feel happy, must not do a whole lot of other things. Everything that doesn’t contribute directly to the progress of work should be eliminated.”A half century later, engi neers began building Rossum’s robot, not out of artificial protoplasm, but of silicon, hydraulics, pneumatics, and electric motors. Robots that were dreamed of by Capek in 1922, that work but do not feel, that perform unhuman or subhuman, jobs in manufacturing plants, are available and are in operation around the world.The modern robot lacks feeling and emotions just as Rossum’s son thought it should. It can only respond to simple “yes/no” questions. The moderrn robot is normally bolted to the floor. It has one arm and one hand. It is deaf, blind, and dumb. In spite of all of these handicaps, the modern robot performs its assigned task hour after hour without boredom or complaint.A robot is not simply another automated machine. Automation began during the industrial revolution with machines that performed jobs that formerly had been done by human workers. Such a machine, however , can do only the specific job for which it was designed, whereas a robot can perform a variety of jobs.A robot must have an arm. The arm must be able to duplicate the movements of a human worker in loading and unloading other automated machines, spraying paint, welding, and performing hundreds of other jobs that cannot be easily done with conventional automated machines.DEFINITION OF A ROBOTThe Robot Industries Association(RIA) has published a definition for robots in an attempt to clarify which machines are simply automated machines and which machines are truly robots. The RIA definition is as follows:“A robot is a reprogrammabl e multifunctional manipulator designed to move material, parts, tools, or specialized devices through variable programmed motions for the performance of a variety of tasks.”This definition, which is more extensive than the one in the RIA glossary at the end of this book, is an excellent definition of a robot. We will look at this definition, one phrase at a time, so as to understand which machines are in fact robots and which machines are little more than specialized automation.First, a robot is a “reprogrammable multifunctional manipulator.” In this phrase RIA tells us that a robot can be taught (“reprogrammed”) to do more than one job by changing the informaion stored in its memory. A robot can be reprogrammed to load and unload machines, weld, and do ma ny other jobs (“multifunctional”). A robot is a“manipulator”. A manipulator is an arm( or hand ) that can pick up or move things. At this point we know that a robot is an arm that can be taught to do different jobs.The definition goes on to say that a ro bot is “designed to move material, parts, tools, or specialized devices.” Material includes wood,steel, plastic, cardboard… anything that is used in the manufacture of a product.A robot can also handle parts that have been manufactured. For example, a robot can load a piece of steel into an automatic lathe and unload a finished part out of the lathe.In addition to handling material and parts, a robot can be fitted with tools such as grinders, buffers, screwdrivers, and welding torches to perform useful work.Robots can also be fitted with specialized instruments or devices to do special jobs in a manufacturing plant. Robots can be fitted with television cameras for inspection of parts or products. They can be fitted with lasers to accurately mearure the size of parts being manufactured.The RIA definition closes with the phrase,”…through variable programmed motions for the performance of a variety of tasks.” This phrase emphasizes the fact that a robot can do many different jobs in a manufacturing plant. The variety of jobs that a robot can do is limited only by the creativity of the application engineer.JOBS FOR ROBOTSJobs performed by robots can be divided into two major categories:hazardous jobs and repetitive jobs.Hazardous JobsMany applications of robots are in jobs that are hazardous to humans. Such jobs may be considered hazardous because of toxic fumes, the weight of the material being handled, the temperature of the material being handled, the danger of working near rotating or press machinery, or environments containing high levels of radiation. Repetitive JobsIn addition to taking over hazardous jobs, robots are well suited to doingextremely repetitive jobs that must be done in manufacturing plants.many jobs in manufacturing plants require a person to act more like a machine than like a human. The job may be to pick a piece up from here and place it there. The same job is done hundreds of times each day. The job requires little or no judgment and little or no skill. This is not said as a criticism of the person who does the job , but is intended simply to point out that many of these jobs exist in industry and must be done to complete the manufacture of products. A robot can be placed at such a work station and can perform the job admirably without complaining or experiencing the fatigue and boredom normally associated with such a job.Although robots eliminate some jobs in industry, they normally eliminate jobs that humans should never have been asked to do. Machines should perform as machines doing machine jobs, and humans should be placed in jobs that require the use of their ability,creativity, and special skills.POTENTIAL FOR INCREASED PRODUCTIVITYIn addition to removing people from jobs they should not have been placed in, robots offer companies the opportunity of achieving increased productivity. When robots are placed in repetitive jobs they continue to operate at their programmed pace without fatigue. Robots do not take either scheduled or unscheduled breaks from the job. The increase in productivity can result in at least 25% more good parts being produced in an eight-hour shift. This increase in productivity increases the company's profits, which can be reinvested in additional plants and equipment. This increase in productivity results in more jobs in other departments in the plant. With more parts being produced, additional people are needed to deliver the raw materials to the plant, to complete the assembly of the finished products, to sell the finished products, and to deliver the products to their destinations.ROBOT SPEEDAlthough robots increase productivity in a manufacturing plant, they are notexceptionally fast. At present, robots normally operate at or near the speed of a human operator. Every major move of a robot normally takes approximately one second. For a robot to pick up a piece of steel from a conveyor and load it into a lathe may require ten different moves taking as much as ten seconds. A human operator can do the same job in the same amount of time . The increase in productivity is a result of the consistency of operation. As the human operator repeats the same job over and over during the workday, he or she begins to slow down. The robot continues to operate at its programmed speed and therefore completes more parts during the workday.Custom-built automated machines can be built to do the same jobs that robots do. An automated machine can do the same loading operation in less than half the time required by a robot or a human operator. The problem with designing a special machine is that such a machine can perform only the specific job for which it was built. If any change is made in the job, the machine must be completely rebuilt, or the machine must be scrapped and a new machine designed and built. A robot, on the other hand, could be reprogrammed and could start doing the new job the same day.Custom-built automated machines still have their place in industry. If a company knows that a job will not change for many years, the faster custom-built machine is still a good choice.Other jobs in factories cannot be done easily with custom-built machinery. For these applications a robot may be a good choice. An example of such an application is spray painting. One company made cabinets for the electronics industry. They made cabinets of many different sizes, all of which needed painting. It was determined that it was not economical for the company to build special spray painting machines for each of the different sizes of enclosures that were being built. Until robots were developed, the company had no choice but to spray the various enclosures by hand.Spray painting is a hazardous job , because the fumes from many paints are both toxic and explosive. A robot is now doing the job of spraying paint on the enclosures.A robot has been “taught” to spray all the different sizes of enclosures that the company builds. In addition, the robot can operate in the toxic environment of the spray booth without any concern for the long-term effect the fumes might have on aperson working in the booth.FLEXIBLE AUTOMATIONRobots have another advantage: they can be taught to do different jobs in the manufacturing plant. If a robot was originally purchased to load and unload a punch press and the job is no longer needed due to a change in product design, the robot can be moved to another job in the plant. For example, the robot could be moved to the end of the assembly operation and be used to unload the finished enclosures from a conveyor and load them onto a pallet for shipment.ACCURACY AND REPEATABILITYOne very important characteristic of any robot is the accuracy with which it can perform its task. When the robot is programmed to perform a specific task, it is led to specific points and programmed to remember the locations of those points. After programming has been completed, the robot is switched to “run” and the program is executed. Unfortunately, the robot will not go to the exact location of any programmed point. For example, the robot may miss the exact point by 0.025 in. If 0.025 in. is the greatest error by which the robot misses any point- during the first execution of the program, the robot is said to have an accuracy of 0.025 in.In addition to accuracy , we are also concerned with the robot’s repeatability. The repeatability of a robot is a measure of how closely it returns to its programmed points every time the program is executed. Say , for example, that the robot misses a programmed point by 0.025 in. the first time the program is executed and that, during the next execution of the program, the robot misses the point it reached during the previous cycle by 0.010 in. Although the robot is a total of 0.035 in. from the original programmed point, its accuracy is 0.025 in. and its repeatability is 0.010 in.THE MAJOR PARTS OF A ROBOTThe major parts of a robot are the manipulator, the power supply, and the controller.The manipulator is used to pick up material, parts, or special tools used in manufacturing. The power supply suppplies the power to move the manipulator. The controller controls the power supply so that the manipulator can be taught to perform its task.外文翻译工业机器人的介绍20世纪60年代当约瑟夫和乔治合作创立了名为Unimation的机器公司，工业机器人便成为了一个事实。