Algorithm of automatic generation of technology process and process relations of automotive wiring h

Computer Aided Drafting, Design and ManufacturingCADDMVolume 22, Number 2, June 2012, Page 47Algorithm of automatic generation of technology process and process relationsof automotive wiring harnessesXU Benzhu, ZHU Jiman, and LIU XiaopingSchool of Computer and Information, Hefei University of Technology, Hefei 230009, ChinaAbstract: Identifying each process and their constraint relations from the complex wiring harness drawings quickly and accurately isthe basis for formulating process routes. According to the knowledge of automotive wiring harness and the characteristics of wiringharness components, we established the model of wiring harness graph. Then we research the algorithm of identifying technologyprocesses automatically, finally we describe the relationships between processes by introducing the constraint matrix, which is in or-der to lay a good foundation for harness process planning and production scheduling.Key words: automotive wiring harness; wire harness graph; identification process; constraint matrix1. IntroductionThe method of generating process automatically isone of the important research issues of the field ofBefore the production of automotive wiring harness,CAPP, the more common methods are based on vari-you need to analyze the harness drawings [1] whichant method [6] and generative method [7-8]. However,contain the types of processes as well as its quantity.the variant method based on the derived principle re-Then you should have reasonable process planningquires the parts of the series structure are similar and[2-3] and make an efficient process route [4-5] in or-processing-shaped surface is also relatively close toder to improve the efficiency of the actual production,each other. During the process of automotive wiringfinally through a series of complex processes such asharness, the characteristics of different types of wiringthe wire cutting, crimping, assembling and so on , itharness components differences significant, and if thecan be processed to complete. However, a me-parameters of the same widget are different, the com-dium-sized automotive wiring harness used to containposition of the processes will also be changed signifi-the number of processes as much as several thousands.cantly, so the method is diffcult to apply to the fieldTo get the processes from harness drawings by ana-of automotive wiring harness. The method that basedlyzing manually, which not only is time consumingon the generative requires for modeling of parts model,but also the accuracy often can not be guaranteed, so itand simulating process design artificially, which causeis difficult to meet the needs of the actual production.the versatility is not good enough, and the wiring har-Therefore, there is important theoretical and practicalness process design requires the participation of op-significance to study the method of identifying thetechnology processes from harness drawings auto-erator in and has a strong field character so that it needto re-modeling and solving. Paper [9] studied thmatically. In addition, the constraint relationship be-typical process sequence is generated based on asso-tween the processes is the basis for the developmentciation rules, and this method can effectively excava-of process routes and production scheduling. Explor-tion associated with a high degree of sequence ofing the method of generating the logical relationshipprocesses, but while the. nrocesses of some relevancebetween processes is an essential part of identifyingis not obvious,中国煤化工processes and making them used to arrange the pro-duction directly.CurrentlyfYHC NM H Gsting of spe-cialized automatic recognition automotive wiring har-Project Iten: Supported by Chinese national Science Foundation (61070124), the Fundamental Research Funds for the Central Unverities (2012HGBZ0195).Correspongirg author: XU Benzhu, E mail: bzxu@hfut.edu.cn万万数据Computer Aided Drafting, Design and Manufacturing CADDM), Vol.22, No.2. Jun. 2012ness processes and their relationships, although thereC,C={r2,"",Ck} stand for there are k connectorsare some large-scale software abroad such as Harn-c(1≤i≤k) is connected to one of the node of V, and itWare, VeSys and so on , which have process identifi-has n ports, which can be inserted m(m≥0) wires. If C;cation module, but the technology has not relevant lit-is a sheath, then n≥1; Ifc; isa ground, then n=1.erature. To study the method of identifying process ofautomotive wiring harmess automatically recognizesthe important practical value. Automotive wiring har-ness process has a strong field characteristics, and the6。1鲁一1.25composition of the technology process and their rela-tions are closely related to characteristics of harness欲贸components and process of production rules and.8.25process knowledge [10] and other. In this paper, firstly,1212 QH 221the wiring harness graph model is established throughDTHNS :H6188 0209the analysis of the wiring harness drawings, then weFig. 1. Example of connectors.combine harness domain knowledge, and the auto-matic generation algorithm of the process is given.Finally, the article made the definition of the logicalIt is shown in Fig.1 are example of connectors,relationship between the processes and gives the algo-which not only contains some wire information suchrithm for solving the constraint matrix of the relation-as wire number, color, diameter and its name and itsship between the processes.type, but also implicitly contains a lot of wiring har-ness process design feature constraints, including the2. Model of wiring harness graphmodel can crimp terminals, the wires need to wear2.1. The definition of wiring harness graphwaterproof bolt, whether the port plug waterproofWiring hamness graph is the source of most of theblock and line-side need to spray the color. These im-data which was required in the actual production [11].plicit information in addition to the properties of theOn the wiring harness graph, connector connected toconnector itself, but also closely related to the wireeach other with wiring harness segment, to whichand its connection properties and process require-wrap and fasteners were attached. If we exclude con-ments.nectors of the wiring harness graph and other wiringConnectors is the process feature vectors of end-harness components, and just to study the part of wires,point, it can be used as the basis for the extractionthe harness can look as a connected acyclic graph.process processes, which will be used in the processesHere are the definition of node, wiring harness andbelow. For example, the right graph in Fig.1,S1 is dueconnector of wiring harmess graph:to the wire, color and diameter attributes as same as(1) Node: The node of wiring harness graph is the13A and 58, so it needs to increase spraying processescollection of the harness segment endpoints andin order to distinguish them correctly assembled in thebranch points. Set V stand for the nodes of the wiringworkshop when the process is generated according tothese characteristics of information.harness graph, then V= 0 or V={v,2,"",m}， v(1≤i≤m) stand for one of the nodes of V. If the degreeWhile the concept of node, wiring harness andof V; is 1, it means V; is an endpoint which is the col-connector has been introduced, the definition of wir-lections of more than one wire; otherwisev; is aing harness graph can be given:branch point which is the connection point of moreDefinition 1 Wiring Harness Graph (WHG) is a tri-than one wire harness.ples (V, E, C), V is the conections of node,E is the(2) Wiring harness: If| V| ≥2, thenV u,v∈V(uconnections of wiring harness, c is the connections of≠v) stand for two different nodes of the wiring har-connector. All the connector of C is connected to oneness graph, the edge e=(u, v) is a wiring harness. Wir-of the node of V, and it is the properties of the corre-ing harness is a bunch of wires containing one or moresponding node， connectors connect to each otherwires. The collection of wiring harmess of wiring har-through wiring harness of E. In addition, wiring har-ness graph is E={er,e,"",en}, e(1≤i≤n) stands for ness is attached to the carrier of packages, fasteners,one or multiple overlapping with wire.etc. in the中国煤化工(3) Connector: The connectors of wiring harnessAccordiI YHc N M H Gge of automotivegraph is a collection of the sheath and ground, whichwiring harness and the process characteristics of wir-is expressed as C. C; stand for one of the connector ofing harness components, the wiring hamess graph hasXU Benzhu et al, Algorithm of automatic generation of technology process and process relations of automotive wiring har-nesses12the following characteristics:ple physical wires that connect to each other and can(1)V v∈V, If degree(v)=1,Then there is one andconduct electrical signals, which is called CLonly one c∈C, meet c→v, That is connector C con-CL={wn,w,"",wn}, wn; is one of the wires of CL,nects to node v; If degree(v)≥2,it need to crimpwhose endpoint locate at the port of connector, andconnection terminal beside the branch point v, and de-corresponds to an endpoint of wiring harness graph.CL is an undirected connected acyclic subgraph ofgree() stand for the degree of v.wiring harness graph, which can be expressed as (V",(2)V e∈E, e is a bunch of wires, and the number ofE", C), itis clear that V"CV, E'CE, C∈C, and theits internal wires contained greater than or equal to 1.edge of CL just is a wire.(3) Vc∈C, c records all the information of wireIf the CL just contains a wire, it is called single line.outside of the length, including line number, color,The collection of all the CL of the wiring harmessdiameter, etc. C Contains a large number of processgraph is called CLS, CLS ={CL,CL2, "',CLn}.information and is an important basis of identificationLoop is not only an important basis for decomposi-process.tion wiring harness of wiring harness graph, but also is(4) While connectors are connected to nodes on thethe basic unit of the process design, such as the con-wiring harness graph, the end of the wiring harnessnection design, which determine the location of theneed to crimp a terminal.crimp terminal in order to determine the properties of(5) For any of packages and fasteners of the wiringthe branch point in the wiring harness graph one byharness graph,3e∈E, makes them dependent on theone in the loop wires.wiring harness e.Fig.2 (a) is a simple wiring harness graph, and its2.2. The expression of wiring harness graphtopology is shown in Fig.2 (b). V~V are the end-points，which connected respectively with sheathThe wiring harness of the wiring harness graph isM01~M07. Vg~VI are branch points. We can extractone or more root overlap wire, and wiring hamessloop through circuit extraction algorithm from thegraph is a connected graph [12]. Triples (V, E, C) thatconnected graph set, in order to show that the logiconly show the topology of the wiring harness graphconnection relationship of wring harness graph, asand process attributes of the endpoint. In order to ex-shown in Fig.2 (c) below. The reason why the wirepress the logical connection relationship of the wiringnumber and its port number are recorded in the table isharness graph, we give the introduction of the conceptthat it can improve the efficiency of the lookup ofof loop.process and its process parameters according to theDefinition 2 Loop is the collection of one or multi-wiring harness technology constraints feature.风| 0.5 | 0.3 ]0.851B2A 5] M01H9C2-021-NH0902-05-R|BB0.50.303HO MO3HO6 MD6H0902-05F-N15DH01 MONO2-301501 100300200.00.. HMOBC91116- 26000150C91116-28000p00茹71A3A 430D405R|Br0.510.85 0.3 ]030.5 IH0902-01F-NHO902- 03F-NNO4.H0902-0240YH08 408HO2 M02RH07 M0715 |b850.5103103H0902- -01MW中国煤化工H0902- -04FWMHCNMHGH04 NG4(a) Sample wiring harness graph50Computer Aided Drafting, Design and Manufacturing (CADDM), VoL.22, No.2, Jun. 2012acteristics of M01，there are five characteristics/2V:F2a={f, f么, fs, f{n, fs}, f: wire color is black (B) andwire diameter is 0.3 mm; f2: one end of the wire con-nect to the 2nd port of M01 and its terminal type isDJ3042-1; fs: the other end connect with 2B and 2C,V1o-V8V10 V11oV7and wire diameter is 0.9 mm; f4: M01 is waterproof ，so the wire endpoints need to do the waterproofingtreatment;, fs: there are wires that have the same prop-erties as the wire 24 in the sheath ports , so it needs0for spray color processing.V5/6Definition 4 Process refers to the sum of one or a(b) Topology mapgroup of workers in a workplace of continuous opera-CL-NO. WN-NO. EndP Cncter HoleNO.tion on a number of objects to complete the produc-1AV1M02tion activities. The process can use the four-tuple1BM01P= to express. N is the name for the proc-10/5M04CL11I/3M03ess. W is the workpiece object set. 0 is the set of op-1/4M06erations. G is the target of the process.1GV7M08One or more processes are usually set in order to2Acomplete a characteristic， therefore,CL22Bone- to- many relationship between the characteristics2Cand process, such as the featuref2 of the last case, ac-3A/1cording to the characteristics of terminal DJ3042-1, ItCL33BM03 ._3(V6M07need firstly remove the skin of a certain length of oneend of the wire 2A (called stripping head) beforecrimping terminals (called side pressure), therefore,the feature requires the two processes to complete(c) Loop setFig. 2. Wiring harness graph and its expression.which are peel head and the side pressure.3.2. The automatic identifcation algorithm of proc-3. Automatic identification of the processesessWiring harness graph is a connected graph, whose3.1. The definition of the characteristics and proc-logical connection relationship can be expressedessesthrough a set of loops, which are the basis of actualThe last chapter has given the definition of wiringproduction. Therefore, loops of the wiring harmessharness graph, and the following will examine how tograph include the process technology processes, anduse the domain knowledge and constraints character-we can extract them through the analysis of the char-istic of the wiring harness parts to identify the proc-acteristics of loops.esses from wiring harness drawings accurately. In or-In order to identify processes of the wiring harnessder to better introduce automatic generation algorithm,we first introduce the concept of feature and process:drawings correctly and automatically, we not onlyneed to know the set of loops, but also make the fol-Definition 3 Feature is constraint set F that thelowing conventions:workpiece of wiring harmess drawings must be metConvention 1: Any node of the table of loop can beaccording to the field of knowledge of harness. Typi-cally, according to the process and purpose of thefound on the wiring harness graph.treatment process, a workpiece(w) can be extractedConvention 2: The nodes whose degree is 1 of theout of n features Fw ={i,f2,"',fn}.wiring harness graph can be found at least once in theSet the loop in Figure 2 for example, it is CL2= {2A,set of loops.2B, 2C}, the loop crimp together with connection ter-Those中国煤化工1yguarantee eachminal at the branch point (V). The other end of thenode prTYHCNMHGsvalid,butalsotowire (24) locates in the endpoint (V2) and connect toensure that every legitimate node is processed so asthe connector (M01). According to the process char-not to lose the process. On this basis, we give the.XU Benzhu et al, Algorithm of automatic generation of technology process and process relations of automotive wiring har-nessesautomatic recognition algorithm of processes in the(3) Calculate the feature set of CL;(Fcu=FEUFr=following:{5tfi,-*m}).STEP1:To get the CLS ={CL,CL2, ,CLm} formSTEP4: j++, Ifj≤m, go to STEP5, otherwise go toWHG by using the algorithm of Circuit extraction, andSTEP2; .initialize is NULL (P=0);STEPS: According tof, analyze the process set (P)STEP2: i++, If i≤n, letj=0, go to STEP3. Other-that could complete it. For V p∈P, extract thewise, Print the harness process set (P), End;workpiece object set and the set of operations and theSTEP3: Analyze the collction of the wiring har-target of the process. Let P=PU Pj, go to STEP4.ness (E={ey,ez,"",en}) and the node set (V= {v1,2,"",The process card shown in figure 3 comes from thev}) of this loop (CL) , and handle as follows:actual production, it means that the loop (CL= {19,1A, .(1) For each edge (ea(1≤a≤k)) of E, Extract the Fa,1}) crimp diagram. We use this example to describethe automatic identification algorithm. The loop is tothen of edge of this loop is F:-FpUFa;focus on only one loop, so CLS={CL}.(2) For each node (vB(1≤b≤)) of V,Ifvbis anThe Wiring harness connections of CL is E= {Ls,Lp,endpoint, search the connector (c) that connected to itLc}and the connections of node is V={vs,VB,VC,VH}.from WHG, then get the features of Vb, which is calledFirstly we extract the characteristics of the wiringFb, and add it to the feature set of CL;(Fr=FyUFb); Ifharness and node, and there are eight features in CL asVb is a branch point, it means that it need to crimpshown in Table.1. Then we analyze the feature one byconnection terminal, so we should extract its featuresone, and get 12 process as shown in Table.2.according to the design result;V100,We0Le)T173631-1TNMwPF-S⑨丹l_DJ454C 1V20100①TMDLM-LLFS9025VBFig. 3. Three wire crimp diagram.Table 1. The feature set of CL.Wiring harnessThe feature setand nodeLA五wire L: color w, area 2.0, length 100 .B_五: wire Lp: color w, area 2.0, length 100Lcf压wire Lc: color W, area 2.0, length 100f4: crimp terminal DA: TNMWPFPAfs: wear waterproofF: FS9025f6 crimp terminal D: TMDLM-Lf: crimp terminal Dc: T173631-1H_f&: crimp terminal De: DJ454CTable 2. The corresponding table of the characteristics and processes.ProcessFeatureNameWorkpiece objectsOperationsTargetsCut wire(p)raw wireCutting wireACut wire(p2)raw wire _Cut wire(Ppx)Pressure(p4)LA +F; DAPress DA toLdLg+F+DAfaPeeling (P3)Peel LAwaterproof(po)L;FWearF to L4Ls+FPressure (P7)Lg; DPress DB toPeel Lg中国煤化工Pressure (P9)Lc;Dcpress DcfYHCNMHGPeling(g (P10)Peel Lc _Pressure (P11)Ls;Le;Lc;DrCombined pressLg+Lg+Lc+DHfPeeling (p2)L;L;LcpeelingLs;Lp;Lc.52Computer Aided Drafing. Design and Manufacturing (CADDM), Yol.22. No.2. Jun. 2012The feature set contained in the above examples isSo it will appear in a significant difference betweenclosely related to the results of process design. Thethe loops as a result of the process design. Table 3 liststerminal location and number of terminal of automo-some typical characteristics of the process and its cor-tive wiring harness loop is different from each other,responding process.which directly affect the composition of the processes.Table 3. Typical characteristics of the process and its corresponding process.KindFeature .ProcessThere are wire information in the port of connectorCut wireEdgeTape and casing attache to EdgewrappedAdhesion components play a fixed role on the edgeAdd fastenersThe wire endpoint that directly connected with the connectors,Pressureand insert into its portMore than two wires are connected at the same nodeCombined pressNodeThe wire properties are consistent in the different ports of theSpray colorsame connectorsThe connectors wwith waterproof requirementsWear waterproofCrimp terminal external requirements of the parcelWear heat shrinkable tube4. Process constraints automatically gener-of Pl|P2 is O∩O2≠0 and-3g1∈G, g2∈G2meet g1∈O2 or g2∈O1.atedThe above definition is the basis to determine the4.1. Logical relationship between the processesrelationship between processes. Take the processes inThe basic logic of the relationship between theTable.2 for example, the target set of wear waterproofprocesses can be divided into three types: sequence(po) is the process object set of the water-side pressurerelationships, mutually exclusive and parallel relations.(p4), P6 and P4 meet sequence relations (p6< p4).ThereP:= and P2= are twoare competing uses of the wire between P4 and p1i,different processes, According to the process objectthat is o4∩o11={L;}≠0, so it is P4田p1. The objectand process objectives of the two processes, we giveis independent of treatment processes between p7 andthe definition of the logical relationship betweenP9, soitispr II P9.them: .It should be noted, that the select relationship exists(1) sequence relationships: Symbolic representationbetween the processes, because sometimes you canas <, P:P1.only choose one to conduct. We study the automatic(2) mutually exclusive relationships: Symbolic rep-identification process composition of wiring harnessresentation as田，Pi and P2 meet the mutually exclu-drawings, which does not involve the use of workshopsive relationship means that they share the same proc-equipment, therefore, select the select relationships areess object while deal with them, that is, P1 and P2 cannot the consideration of this article.not be processed at the same time, and must be com-4.2. The automatic generation algorithm of logicalpleted one before the other, but they does not existrelationship between the processesbetween the sequence relationship between them.To identify correctly the logical relationship be-Therefore，the necessary condition of P1田P2 istween the processes is the basis for determining theo∩O2≠e.route of actual production process, and arranging(3) parallel relations: Symbolic representation asl|,producti中国煤化工et of n processesP1 and P2 meet the parallel relation means that they(P=. {P1YHCNMH Gonstraint matrix tocan be processed at the same time and there are notrepresent the logical relationsp between processes,impact between each other. The necessary conditionsand the matrix elements (A[iJi](1 ≤ij≤n)) stand forXU Benzhu et al, Algorithm of automatic generation of technology process and process relations of automotive wiring har-. nesses53the logical relationship of p; and Pj. .nation of connectors, we can extract the processesUsually a medium-sized wiring hamess drawingsshown in the Fig.4 (c) by using the algorithm ofincludes thousands of process, if we use one constraintautomatic identification ; The logical relationship be-matrix to describe the logical relationship between thetween the process of mutual constraint graph by thevarious processes, the matrix's size will be enormous.matrix shown in Fig.4 (d) given. Similarly, we canTaking into account the actual production of the har-draw the other loop processes set and the constraintness shop, loop is the basic unit, and processes ex-matrix. The process set and the constraint matrix is antracted from the different loop should be independentimportant basis for the development of process routesof each other and mutual non-interference. If we useand process planning.one constraint matrix to describe the logical relation-ship of one loop, it can significantly reduce the matrixEof the overall scale, then all the processes in the wir-ing harness drawings constraints can be expressed as a01s0column matrix vector (A={A,A2,"An), A; is a ma-200s0_ 10030trix ,which express the loop-constraint relation of CLj.The algorithm for automatic generation of the har-ness process constraints based on the above, are givenin the following:STEP1: Get the number of loops in the wiring har-ness drawings, let i=1, initialize process constraint(a) loopmatrix (A) to a n dimensional column vector(A1,A2,"An).FS9026D_62]-V6.3AB 03 750STEP2: If i>n,the algorithm ends. Otherwise, to少cextract the processes of CL; and get the seDJ221-4A6619223KsS(P= {P.P2,""" ,Pm}) using process automatic identifica-B 0.3 350DJ454A2_ B03350-②日tion algorithm, and initialize A; to a square of mxm,Aand letj=1.(b) schematic diagramSTEP3: Ifj>m,Then =i+1,go to STEP2.ProcName Workiece_Op-SeObj-SetCutLnLineCut LzA21STEP4: Let k=j+1,A[i][j]='-'.Cut L28Cut LacnCSTEP5: If k≤m, According to the harness charac-ColorPntLasColorPnt L2tWrtPrf-BItFg、L2Fp ToL2cLac+Fgteristics and the workpiece set of objects of processes,CrimpDA. L2sCrimp AL2u+ Dato determine the relationship between the two. If theyDg. L2BCrimp BL28+ DgW-Crimp Dc. Fg.LacCrimp CL2c +Fg+ Dcmeet sequence relationships, let AI[i][k]='<',D1 L2s L28M-Crimp HA.[k][j]='>'; If they meet mutually exclusive relation-2C2cships, let A.[i][k]= A.[k]i]= ' 田',Otherwise let(C) processA[][k]= A[k][j]='lI'. k++, go to STEP5.PiP2P3P4PsP6P7PgP，STEP6: j=j+1,go to STEP3.P1||>||>||||The fllowing takes the 2nd loop (CL= {24,2B,2C})P2||-II1|I|II|>>shown in Fig.2 shows for example, and gives the briefdescription of the process of automatic identificationP3| II|| -|I||>and mutual logical relationship generation.P4Fig.4 (a) shows the line topology structure of thePs||