夾具類外文翻譯-工業(yè)機(jī)械手夾具的運(yùn)動(dòng)合成——一種創(chuàng)造性的設(shè)計(jì)方法【PDF+WORD】【中文1000字】,PDF+WORD,中文1000字,夾具,外文,翻譯,工業(yè),機(jī)械手,運(yùn)動(dòng),合成,一種,創(chuàng)造性,設(shè)計(jì),方法,PDF,WORD,中文,1000 257 End Effects Kinematic Synthesis of Industrial Robot Hand/Gripper一A Creative Design Approach Jay Lee United States Postal Servic,Office of Advanced Technology,475 LEnfant Plaza S.W.,Rm 2140,Washington DC 20260-812 U.S.A.The purpose of this research is to synthesize industrial robot hand mechanisms.Investigations on DOF（凹，complexity and the structure(Graph)will be presented.Therefore,a kinematic structure table of robot hand mechanisms can be generated.The advantages of using this reference table are as follows:Identification of the kinematic structure of robot handmechanisms for robot hand standardization.幣1e atlas of graph(structure)can be used to enumeratenew robot hand mechanisms.Leads to creation or invention of new robot hand mechanisms according to the separation of structure and function.lis paper will present a creative design approach in designing industrial robot hand/gripper mechanisms.This research work was conducted while the author was at Columbia University.Keywords:Kinematics,Grippers,Hand mechanisms.North-Holland Robotics 4(1988)257-263 1.IntroductionRobotic hand/gripper is the integral part in most of the robotic applications.Market study predicted that there will be over 60%robotic applications in assembly and material handling l.Design of the robotic gripping mechanism always becomes the key element for the entitled project.Often,very little time is spent in optimal kinematic structure(topology)design in the early stages of a design process.Time pressures sometimes force engineers to repeat topologies that have worked in similar applications in the past,rather than try to create better designs 2.Chen 3 presented a complete su凹ey of mechanisms used for grippers for industrial robots.Erdman et al.2 suggested techniques of type synthesis based on graph the?？蒩nd expert systems.Some extensive work in creating database for robotic hand(grippers)mechanism has been done by the author 8.This paper will present a creative design ap-Mr.Jay Lee is program director in material handling research for the Office of Advanced Technology of United States Postal Service.He re侃ived his B.S.from Taiwan and holds an M.S.degr民in Mechanical Engineering from the University of Wisconsin-Madison and an M.S.in Industrial Management from State University of New York at Stony Brook.He is currently a doctoral candidate in Mechanical Engineering at University of Mal)land.He has served as a part-time lecturer for the State Uruversity of New York at Stony Brook,for the Polytechnics University and as adjunct assistant professor for the New York Institute of Technology.He fo口nerly served as a program manager in developing high precision and high sp四d ro otic technologies for Anorad Corp.(Hauppauge,NY).Before Anorad,he was a senior mechanical engineer and group leader in developing vision-guided robotic technologies for Robotic Vision Systems,Inc.also in Hauppauge,New York.0921-8830/88/$3.50 1988,Else世er Science Publishers B.V.(North-Holland)258 J.Lee/Kinematic Synthesis of Industrial Robot Hand/Gripper proach in designing industrial robot hand/gripper mechanism.The development of the kinematic structure of robot hand/gripper mechanisms will also be presented.2.Overview of Industrial Robot Hand(Gripper)Mechanism(3)In general,grippers can be classified according to the following:(1)Mechanical finger type:According to thenumber of fingers in a gripper,we have(i)2 finger type（垃）3 finger type(iii)multifinger type.According to the number of hands mounted on the wrist of the robot arm we have(i)single gripper（總）dual gripper(iii)multiple gripper(index type).According to the part configuration,we have(i)linear motion gripper(paraller)(ii)angular motion gripper.According to the kinematic structure,we have(i)linkage type(ii)gear and rack type仙i)cam type(iv)screw type(v)rope and pulley type(MIT/UTAHhand,Hitachi hand).(2)Vacuum and magneticpe:this class ineludes three fitted with suction cup or electromagnets.(3)Special hand and gripper:this class consistsof inflatable finger,paper picking gripper.In this paper,we will investigate mechanical finger type because most industrial robot hand/gripper mechanisms fall into this category.2.1.Kinematic Synthesis of Robot Hand(Gripper)Mechanism Mechanism creation based on the separation of structure from function was proposed by Freudenstein 4一7.Kinematic structure can be enumerated in an essentially systematic,unbiased fashion as a function of the degree of freedom of the mechanism,the natural of the desired motion and a parameter representing an indication of the complexity of the mechanism.Each structure obtained in this way can then be sketched and evaluated with respect to the functional requirements of the mechanism.Potentially acceptable mechanisms can then be evaluated in depth until a final design is achieved.Most mechanisms obey the following generaldegree-of-freedom equation:F（L-J-l)+Lh、，IJ，、where F=degree of freedom of mechanism Degree of Freed。m(f)Kinematic Element 2 耐WMWA四494 Comments Helical Pair(H)Gear Pair(G)Turning Pair(R)Sliding Pair(P)Ball in Cylinder Fig.1.Common used kinematic elements in robot hand/gripper mechanism.J.Lee/Kinematic Synthesis of Industrial Robot Hand/Gripper259 Table 1 Correspondence between graph and mech缸rismMechanism Links 且Joints(j)旦旦EVertices(vJ Edges(el 些主主 Joined Links Edge-connected vertices Different Joints Labeled Edges R=Pin Joint P=Slid工ng Joint G=Gear Joint H=Helical Joint Gr口unded Element Fixed Link Same Mechanisms 工somorphic Graphs Different Mechanisms Noniscmorphic Graphs 工口dependent Loops 工ndependent Loops mobilit number(degr四of fr臼dom in whichmechanism operates:3 for plane and spherical motions；6 for general three-dimensional motions),L=number of links,j=number of joints,and/;=degree of fr創(chuàng)om of relative motion at ith joint.In terms of the graph of the mechanism,Equation(1)may be written asF（e-1)+I:1;(2)where v=number of vertices of graph(v=L)and e=number of edges of graph(e=j).LIND=j-L+1(3)LIND=Number of independent loops in the mechanism combining(1)and(3)L/;=F+LIND(4)For gear trains it can be shown 7)that these equations specialize to the following:L=F+l+LIND j=F+2 LIND Ja=LIND 1R=F+LIND R p G H LIND where 元，iRdenote the number of gear pairs and pin joints.Most robot hands(grippers)are openloop mechanisms whose structures are generally simpler than those of close-loop mechanisms.The 6 b CFig.2.Typical robot hand mechanism and graph.260 J.Lee/Kinematic Synthesis of Industrial Robot Hand/Gripper KINEMATIC ROBOT HAND NO V MECHANISM STRUCTURE 句5 E三R 2 句5 仨三噸2 r,3 3 也5E三剖仨2 R 3 句5 6 曰：13 R 句Fig.3.Kinematic structure of robot hand mechanisms.most common joints in robot hands(grippers)mechanisms are the turning pairs or pin joints(R),the sliding pair(P),gear pairs(G),helical pairs or screw-and-nut(H)(see Fig.).Table I shows the espondence between graphs and m民hanisms.The graph representation of a typical robot hand mechanism is shown in Fig.2.The degree of freedom(F)and complexity(LIND)can be illustrated by use of example from Fig.2.Number of links(L)=6 Number of joints(j)=7 匯兀RRPRRRR=7 3(plane mechanism)KINEMATIC ROBOT HAND NO V e STRUCTURE,MECHANISM 5 5 6 3寫(xiě)26 6 7 -*3 R 句7 6 7 扣留Therefore F=3(L一j+1)+L,/;=3(6-7一1)+7=1The number of closed loops in this mechanism is(a)LIND=j-L+1=7-6+1=2 This should be equal to the result from the graph(b).From Table I we know that the number of edges(e)in the graph is equal to the number of links in the mechanism.The number of vertices(v)in the graph is equal to the number of joints(j)in the mechanism.J.Lee/Kinematic Synthesis of Industrial Robot Hand/Gripper 261 Therefore LIND can be rewritten in the following form:LIND=l+e-v=l+7-6=2 2.2.Creating of Kinematic Structure(Graph）盧rIndustrial Robot Hand/Gripper Mechanism In order to lead to creation or invention of new robot hand/gripper mechanisms according to the separation of structures and functions,a kinematic structure reference table of industrial robot/gripper mechanism should be generated.Over hundreds of different indistrial robot hand/gripper mechanisms have been investigated by the author.Fig.3 shows parts of these kinema tic structures(design database)which are generated by the author.be advantages of using this reference table are as follows:2(1)Identification of kinematic structure ofrobot hand/gripper mechanisms.(2)The atlas of graph(structure)can be used toenumerate new robot hand/gripper mecharusms.4 H 3 Fig.4.Example 1.3 R 4 Fig.5.Example 2.(3)Leads to creation or invention of new robothand/gripper mechanisms according to theseparation of structure and function.2.3.Creative D臼ign of Industrial Robot Hand/Gripper Mechanism The following examples will show how to do creative design from the generated kinematic structure(design database).Example 1.In Fig.3,numbers 1,2 and 3 have the same vertices（時(shí)，edges(e)and kinematic structure(graph).If we look at these graphs without looking at the robot hand mechanisms,we can find that the differences among these three graphs are kinematic element at link 2-link 4,and link 2-link 3.Number I is prismatic joint(P).Number 2 is gear joint(G)and number 3 is pin joint(R).If we would like to design a new robot hand by use of another type of kinematic joint,we could use the Helical Joint(H).The H joint will replace 262 J.Lee/Kinematic Synthesis of Industrial Robot Hand/Gripperthe above mentioned P,G and R joints.Therefore,a new graph and hand/gripper mechanism can be presented and designed(Fig.4).In Fig.4two fingers are driven by a motor through a pulley to drive a screw bar 11.Example 2.Let us compare number 6 and 7 from Fig.3.They have s創(chuàng)ne number of vertices(v)and edges(e)and same graph.If we would like to modify these mechanisms by use of gears,what kind of modifications should be done?Obviously,if we are going to use gears,the gears have to be fixed and rotate about the pin joint with the fixed link.Therefore,link 3 and link 5 have to be replaced by G.The modified graph and modified design of new robot hand/gripper mechanism can be shown in Fig.5.SEARCH PROCESS(RULES)MODIFICATION RETRY M。dified Data Fig.6.Database retrieve/storage system for robot hand des,gn.半J虧一百4毒S睛、Fig.7.User-machine interface in expert system.2.4.Expert System Approach to Robot Hand/Gripper Mechanisms Expert systems consist of three m句or compo-nents 10:a database;rules for transforming the database;a control strategy for selecting which rule toapply next.The database is a representation of parameters important to the problem.The rules of an expert system encode knowledge about how to reason from one set of facts to another.The controlstrategy determines which rules to apply when several rules are applicable.In general,expert systems are useful in the following sorts of task:debugging design diagnosis interpretation prediction monitoring plannin instruction modification.The most difficult phase of mechanical designis the conceptual phase.By use of the generated kinematic structure(Design Database),an expert system can be created.This knowledge base system contains general information about robot J.Lee/Kinematic Synthesis of Industrial Robot Hand/Gripper 263 hand/mechanisms,kinematic structures(graphs),functions,types of drive mechanisms and applications.The designer enters the design requirements,the master will select the appropriate mechanisms and graphs from design database according to the functions,drive mechanisms,and applications.The designer can then study these proposed kinematic structures.Potentially acceptable mechanisms can then be evaluated in depth until a final design is achieved.Fig.6 shows the database retrieve and storage system in a knowledge base system for creative design of robot hand/gripper mechanism.Similar study has been conducted by Chase and Roberts(9).Fig.7 shows user-machine interface for creative design and robot hand/gripper mechanism.3.SummaryBy using kinematic structure(graph)the?？?，acreative design approach has been presented for designing robot hand/gripper mechanisms.A knowledge base design database system can also be created through the generated kinematic structure table of robot hand/gripper mechanisms.References l)U.S.Robotics Market Study,Frost&Sullivan,1986.2 Arthur G.Erdman,Thomas Thompson and Donald R.Riley，“Type Selection of Robot and Gripper KinematicTopology Using Expert Systems”，International Journal of Robotic Research,Vol.5,No.2 Summer 1986,pp.183-189.(3)Fan Yu Chen，“Gripping Mechanisms for IndustrialRobots”，Mechanism and Machine Theory,Vol.17,No.5,pp.299-311,1982.4 Freudenstein,F.and E.R.M球i，“TheCreation of Mechanisms According to Kinematic Structure and Function氣General Motors Research Publications,GMR 3073,September 1979.5 Freudenstein,F.and E.R.Maki，“Development of anOptimum Variable-Stroke Internal Combustion EngineerMechanism from the Viewpoint of Kinematics Structure”，ASME 82-DET-29,September 1982.(6 Dobrjansky,L and F.Freudenstein，“Some Applications。f Graph Theory to the Structure Analysis of Mech缸tism”，Journal of Engineering for IndustFeb.1967.7 Buchsbaum,F.and Freudenstein,F.“Synthesis ofKinematic Structure of Geared Kinematic Chains andOther Mechanisms Journal of Mechanism,1970,pp.357-392.(8 Le吧，J“Kinematic Synthesis of Industrial Robot Hand Mechanisms”，Columbia University Project Report,Fall 1985.(9 Chase,T.R.and Roberts,TR.University of Rhode Island Kingston,RI.(10)Soroka,Barry Irvin，“Expert Systems and Robotics”Robots 8 Conference Proceedings,pp.19 132,140.11)Shaum,Loren，“Programmable End-Effectors EAS Interface”Schaum Manufacturing,Inc.Elkhart,IN.