A Planning Approach of Engineering Characteristics Based on QFD-TRIZ Integrated

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1 A Plag Approach of Egeerg Characterstcs Based o QFD-TRIZ Itegrated Shag Lu, Dogya Sh,, ad Yg Zhag College Mechacal ad Electrcal Egeerg, Harb Egeerg Uversty, Harb 5, Cha Postdoctoral Research Stato of Istrumet Scece ad Techology, Harb Uversty of Scece ad Techology, Harb 5, Cha {Shag.Lu,Dogya Sh,Yg.Zhag,QQLSCN}@6.com Abstract. Tradtoal QFD plag method compromses cotradctos betwee egeerg characterstcs to acheve hgher customer satsfacto. However, ths compromse trade-off ca ot elmate the cotradctos estg amog the egeerg characterstcs whch lmted the overall customer satsfacto. QFD (Qualty fucto deploymet) tegrated wth TRIZ (the Russa acroym of the Theory of Ivetve Problem Solvg) becomes hot research recetly for TRIZ ca be used to solve cotradctos betwee egeerg characterstcs whch costruct the roof of HOQ (House of qualty). But, the tradtoal QFD plag approach s ot sutable for QFD tegrated wth TRIZ for that TRIZ requres emphaszg the cotradctos betwee egeerg characterstcs at problem defto stage stead of compromsg trade-off. So, a ew plag approach based o QFD / TRIZ tegrato s proposed ths paper, whch based o the cosderato of the correlato matr of egeerg characterstcs ad customer satsfacto o the bass of cost. The proposed approach suggests that TRIZ should be appled to solve cotradctos at the frst step, ad the correlato matr of egeerg characterstcs should be ameded at the secod step, ad at et step IFR (deal fal result) must be valdated, the plag eecute. A eample s used to llustrate the proposed approach. The applcato dcated that hgher customer satsfacto ca be met ad the cotradctos betwee the characterstc parameters are elmated. Keywords: QFD, TRIZ, product plag, egeerg characterstcs. Itroducto Product plag s the key step at the early stage of products desg. Qualty fucto deploymet (QFD) became a well kow customers-oreted product developmet tool for traslatg customer voce to varous stages of product desg cludg product plag stage. As the mportat parameters of product plag, egeerg characterstcs (ECs) costructg the roof of house of qualty (HoQ) carate the customers requremets (CRs). So a reasoable product plag s the base of meetg overall customer satsfacto. I the last decade, product plag based o QFD has bee udertake by researcher [-5]. But all these approach metoed above have the same meas to deal wth cotradctos betwee ECs, whch s compromse trade-off. R. Ta, G. Cao, ad N. Leó (Eds.): CAI 9, IFIP AICT 3, pp. 7 6, 9. IFIP Iteratoal Federato for Iformato Processg 9

2 8 S. Lu, D. Sh, ad Y. Zhag QFD ca solve the problem of "what to do", but ca t aswer the questo of "how to do", ad TRIZ provdes a seres of problem-solvg tools, so tegrated QFD ad TRIZ ca solve the problems of "what to do " ad "how to do" desg process [6]. The methods of QFD tegrated wth TRIZ were dscussed papers [7-9]. TRIZ (Theory of Ivetve Problem Solvg) cosders that techology system evolves towards IFR (deal fal result), ad the resolve of cotradctos betwee desg parameters s the drvg forces of techology systems evoluto. TRIZ promotes emphaszg the cotradctos betwee parameters at problem defto stage stead of compromsg trade-off. Therefore, the product plag method based o the tradtoal QFD s ot sutable for QFD / TRIZ tegrated desg model, a ew plag approach s eeded. Ths paper proposes a desg method of product plag based o QFD ad TRIZ cotradctos tools tegrated, as well as the cosderato to the aalyss of the correlato matr of ECs ad the costrats of eplotato cost. QFD/TRIZ Itegerated Product Plag Methods. Plag Process Model The plag process of proposed approach s show Fgure, whch suggest a fve step plag process. The frst step s to costruct the HOQ. Correlato matr whch composed of the roof of HOQ s the key to QFD tegrated wth TRIZ for that t s ot oly mportat for detfyg the weght of ECs but also mportat for Fg.. Egeerg characterstcs plag process model

3 A Plag Approach of Egeerg Characterstcs Based o QFD-TRIZ Itegrated 9 applyg TRIZ. The secod step s to detfy the techcal cotradctos. The techcal cotradctos represet the teractve costrats of ECs, whch lmt the overall customer satsfacto. If the cotradcto ca be elmated at the early stage of product plag, hgher customer satsfacto wll be met. The detals wll be llustrated secto.3. The thrd step s to detfy the physcal cotradctos estg the correlato matr, ad the elmatg operato wll also be eecuted to meet hgher overall customer satsfacto, ad the detals wll be llustrated secto.. The forth step s verfcato. The style of cotradcto should be dstgushed. If the cotradcto s techcal cotradcto, cotradcto matr wll be employed to solve the problem. If the cotradcto s physcal cotradcto, separatg prcple wll be appled. The the IFR valdato step s essetal for cost cosderato. I the last step, the olear programmg based o Che Yzeg s approach s employed to deal wth optmzg problem.. Costructg HoQ Costructg HoQ volves the collecto of epert opo to detfy the data show as follow:. Customer requremets whch costruct the left wall of HoQ are deoted by CR s, ad CR represet the -th customer requremet.. Egeerg characterstcs whch costruct the celg of HoQ s deoted by ECs, ad EC represet the -th egeerg characterstc. 3. Correlato matr whch costructs the roof of HoQ s deoted by P, ad represets the teractve relatoshp of egeerg characterstcs. p s the elemet of P, represet the teractve stregth betwee EC ad EC, where (,] p.. Relato matr whch reflect the relatoshp betwee CRs ad ECs costruct r s the elemet of R represet the room of HoQ, ad s deoted by R. teractve stregth betwee CR ad EC. 5. The egeerg characterstcs value from compettve compay whch costructs the floor of HoQ s used to be referece. 6. The upper lmt deoted by l ma ad lower lmt deoted by l m of ECs s essetal for product plag whch are set by the developer accordg to the physcal lmt ad the parameters of compettve eterprse. 7. Cost coeffcet s essetal for product plag accordg to Che Yzeg s approach, whch costructs the foudato of HoQ, deoted by.3 Idetfyg Techcal Cotradctos cf. The teractve relatoshp betwee egeerg characterstcs ca be classfed to postve costrat relatoshp ad egatve costrat relatoshp. The postve

4 S. Lu, D. Sh, ad Y. Zhag costrat relatoshp meas f the -th egeerg characterstc should be mproved, the -th egeerg characterstc eed to be mproved at the same tme. The egatve costrat relatoshp mea f the -th egeerg characterstc should be mproved, the -th egeerg characterstc eed to be worseed at the same tme. Ad the egatve costrat relatoshp whch s called cotradcto TRIZ ca be mapped to cotradcto matr to fd the soluto. A method s come up wth referece [] to fd the techcal cotradcto from HOQ. As s show Fg., there s a cotradcto betwee EC ad EC. The EC s mapped to P m (TRIZ egeerg parameter for mprovg parameter) ad EC s mapped to P (TRIZ egeerg parameter for worseg parameter). The solutos est at the cross of row m ad colum. Ths soluto s appled to mprove the capablty of system ad the cotradcto betwee EC ad EC wll be elmated. Fg.. Model of HoQ tegrated wth cotradcto matr. Idetfyg Physcal Cotradctos Egeerg characterstcs eed to grow both postve ad egatve drecto at the same tme for the requremet of mprovg capablty of product, whch s called physcal cotradcto TRIZ. A approach combed QFD wth fucto decomposto to solve the physcal cotradctos was proposed referece []. As s show Fg.3, system fucto ca be decomposed to several sub-fucto from to whch are deoted by SF SF SF,. Ad these fuctos are affected by egeerg characterstcs. For eample, a postve chage requremet o EC emerge to mprove sub-fucto SF, meawhle a egatve chage requremet o EC emerge to mprove sub-fucto SFy, so the physcal cotradcto emerge o egeerg characterstc EC. Separatg prcple s proposed to elmate the physcal cotradcto.

5 A Plag Approach of Egeerg Characterstcs Based o QFD-TRIZ Itegrated Fg. 3. Mappg of HoQ tegrated wth decomposed fucto.5 Dealg wth Correlato Matr of Egeerg Characterstcs Cotradctos ad costrats est egeerg characterstcs, whch fluece the mprovemet of egeerg characterstcs. Postve correlato s kow as costrat ad egatve correlato s kow as cotradcto. I customer satsfacto plag process based o the cosderato of cost, the estece of costrats ca t lmt customer satsfacto, but the correspodg mprove of egeerg characterstcs wll be lmted by developmet cost. Customer satsfacto wll be lmted for the estece of cotradctos. Customer satsfacto wll mprove f these cotradctos ca be elmated. TRIZ s employed to elmate these cotradctos. Therefore, the matr of egeerg characterstcs s doe as follows:. Keep costrat relatos to costrat tems.. Orgal cotradcto relatoshps wll be saved f solutos ca t be foud to solve the cotradctos by TRIZ to the cotradctos tems. If solutos ca be foud by usg TRIZ, the IFR must be valdated. If the valdato s successful, these cotradctos wll be revsed to, otherwse the orgal relatoshp of cotradcto wll be kept. TRIZ IFR valdatg method: TRIZ theory cosders that resolve of cotradctos betwee desg parameters s the drvg force of techology systems evoluto. Techology system evolves UF towards mprovemet of IFR ad IFR ca be epressed as I = HF + C. Where I s the deal degree of techology systems, ad UF s useful fucto of systems, ad HF s harmful fucto of system, ad C s the cost. Obvously, order to mprove the deal degree of techology systems, t s ecessary to crease the useful fuctos, ad reduce harmful fucto, or reduce the cost. I applcato of TRIZ to solve the cotradctos, system resources should be cosdered. Whether the

6 S. Lu, D. Sh, ad Y. Zhag solutos geerated by TRIZ wll gve rse to etra cost must be cosdered. If t wo t cause etra cost, the valdato s successful..6 Nolear Programmg Based o Che Yzeg s approach [], we come up wth a systematc flow product plag. It s composed of e stages.. To detfy the weght mportace of customer requremets whch s deoted by Vector W. w represets the -th elemet of W correspodg to weght mportace of the -th customer requremet. Ad aalytcal herarchy process (AHP)[] s employed to calculate the value of W, where < w <, w = m =, ad m s the cout of customer requremets.. To detfy the actual mproved rato [] ad the pla mproved rato [] of egeerg characterstcs. The pla mproved rato deoted by s defed as the percet of egeerg characterstc whch should be reachg order to mprove the capablty of product wthout cosderg other egeerg characterstcs effect. The actual mproved rato deoted by y s defed as the percet of egeerg characterstc whch should be reachg order to mprove the capablty of product wth cosderg other egeerg characterstcs effect. The -th egeerg characterstc s actual mproved rato y ca be calculated by epressos y ( p ) = +. Where k k k = k characterstc s pla mproved rato ad s the th egeerg p k s the elemet of correlato matr P represet the relato stregth betwee EC ad EC. The cout of egeerg characterstcs s deoted by. 3. To detfy the customer satsfacto whch s deoted by Vector U ad u s the th elemet of Vector U correspodg to the th customer satsfacto, whch ca be calculated by epressos U = RX. Where X represets the pla mproved rato Vector.. To detfy the weght mportace of EC whch s deoted by Vector V, where V T V = R W. The ormalze the Vector V, we got v v, v, v3,... v v =, < v, < v =. = v [ ] T =, =

7 A Plag Approach of Egeerg Characterstcs Based o QFD-TRIZ Itegrated 3 5. To detfy the overall customer satsfacto whch s deoted by fucto S (X ). T S( X ) = ( V ) X = v. k= k k 6. To create cost costrat fuctos accordg to the epressos C ( y ) = cf y, where cf s cost coeffcet represet the cost for mprovg the -th egeerg characterstc ad ca be calculates by epressos cf cf ( p ) cf s the pla cost coeffcet of EC. =. k k k = k 7. Creatg other costrat fuctos accordg to boudary codto. 8. Modfyg the correlato matr P accordg to the result of applyg of TRIZ. 9. Smulato..The, the olear programmg model s show as follow: ma s. t. S( X ) = ( V k = ) cf ( p k )( + = k = k = k k α k p k T ( =,,, ) X = k = k k v p k ) T () 3 Illustrated Eample ad Smulato Results Verfy the reasoableess of the proposed approach ths paper by usg eamples of referece []. There are four customer demads ( CR, CR, CR3, CR ), seve egeerg characterstc parameters ( EC, EC,, EC7), ad two competto eterprses ( comp, comp ). Product house of qualty s show Fg.. Relatve weght of customer requremets W ca be calculated by the method of AHP, ad W = (.6,.8,.6,.). Correlato matr of customer requremets ad egeerg characterstcs deoted by R ca be detfed from the room of

8 S. Lu, D. Sh, ad Y. Zhag Fg.. Product House of Qualty HoQ. Correlato matr of egeerg characterstcs deoted by P ca be detfy from the roof of HoQ, where P = It ca be see from the matr that there are techology cotradctos betwee EC ad EC 6. EC s loadg effcecy, ad EC6 s cam drvg ose. I order to mprove the effcecy of loadg effcecy, the speed of cam must be ehaced, but meawhle t wll crease drvg ose (The reaso s hgh-speed drvg mpact by the cam). Egeerg characterstcs are mapped to egeerg parameters of TRIZ, EC mapped to speed, ad EC6 mapped to Teso / Pressure, TRIZ prcple umbers are requred (6, 8, 38, ad ), ad the th prcple s the composte materals. Stayl PA6 materal s adopted, the the cost less tha the quodam cam ad the ose s lower. The problems are solved, ad the cotradctos are removed, as well as ot lead to addtoal cost. The cotradctos are ot foud egeerg characterstcs.

9 A Plag Approach of Egeerg Characterstcs Based o QFD-TRIZ Itegrated 5 Therefore, revse matr P, P = Set up mathematcal programmg model ad costrat codtos accordg to epressos (): ma s. t. S ( ) = , ,3,5,6, Usg MatLab optmzato toolbo to solve, ad optmze results are show Table. 7 ma S( X ) Table. Smulato Result The results verfy that overall customer satsfacto mproves 5.75% compared wth referece [] s. Coclusos To emphaszg the cotradctos amog the egeerg characterstcs stead of compromse trade-off at the early stage of product developmet s proptous to solve problem ad promote the evoluto of techology systems accordg to TRIZ. So tradtoal method for product plag based o the compromse trade-off s ot sutable for the applcato QFD tegrated wth TRIZ. A ew product plag

10 6 S. Lu, D. Sh, ad Y. Zhag approach s proposed ths paper, we suggest that cotradcto matr ad separatg prcple should be employed to elmate the cotradctos estg amog the egeerg characterstcs before product plag, ad IFR valdate s essetal for the cost cosderato. Smulato result shows that the proposed approach ca meet hgher customer satsfacto, whle the cotradctos whch baffle the developmet of techcal system are elmated. Refereces. Che, Y., Tag, J., Re, L., et al.: A Optmal Model Based o House of Qualty. Cha Mechacal Egeerg, (3). Moskowtz, H., Km, K.J.: QFD Optmzer: A Novce Fredly Qualty Fucto Deploymet Decso Support System For Optmzg Product Desgs. Computers & Idustral Egeerg, (997) 3. Tag, J., Rchard, Y.K.F., Xu, B., et al.: A ew approach to qualty fucto deploymet plag wth facal cosderato. Computers & Operatos Research 9, 7 63 (). Ertugrul Karsak, E., Sozer, S., Emre Alptek, S.: Product plag qualty fucto deploymet usg a combed aalytc etwork process ad goal programmg approach. Computers & Idustral Egeerg, 7 9 (3) 5. Che, L.-H., Ko, W.-C.: Fuzzy approaches to qualty fucto deploymet for ew product desg. Fuzzy Sets ad Systems. I press, Corrected Proof, Avalable ole December (8) 6. Ta, R.-H., Ma, J.-H., Zhag, H.-G., et al.: Study o the coceptual desg process based o QFD ad TRIZ. Mache Desg 9 () 7. Lu, C., Lao, Z., Jag, S., et al.: Research o ovatve product desg system based o QFD ad TRIZ. Materals Scece Forum. I: Advaces Materals Maufacturg Scece ad Techology II - Selected Papers from the th Iteratoal Maufacturg Coferece Cha, vol , pp. 7 (6) 8. Wag, H., Che, G., L, Z., et al.: Algorthm of tegratg QFD ad TRIZ for the ovatve desg process. Iteratoal Joural of Computer Applcatos Techology, 3 35 (5) 9. Sh, G.-l., She, Y.-g.: Study o problem-solvg theory based o QFD, TRIZ ad Taguch methods. Systems Egeerg ad Electrocs, (8). Noel, L.: A ew model of the coceptual desg process usg AFD/FA/TRIZ. TRIZ Joural, Armacost, R.L., Compoato, P.J., Mchael, et al.: A AHP Framework for prortzg Customer Requremets QFD. A Idustralzed Housg Applcato. IIE Trasacto, (99). Mu, R., Zhag, J.-t.: Applcato of qualty house techology the refrgerator desg based o qualtatve fucto dsposto. Joural of Mache Desg, 5 8 (7)