124CHNG 3. NG DNG PHN MM CAD/CAM CIMATRON TRONG THIT K, CH TO KHUN MU pngnhucungycngtngtronglnhvcthitkvgiacng.Nhiu cng ty pht trin phn mm v cc vin nghin cu trn th gii a ra hng lotcc phn mm tr gip trong lnh vc ny v khng ngng pht trin chng tngcngthmccchcnngchochngcngnhlmchovicsdng chng tr nn thun tin hn. Cchthngphnmmtrgipvicthitkvgiacngcphttrintheo hai hng chnh: Cc phn mm thuc nhm " Best in Class" Cc phn mm tch hp " Integrated System " 1. Cc phn mm " Best in Class" Ccphnmmthucnhmnythngthchinmtchcnngtrgip c th v d nh : Thit k cc m hnh hnh hc, phn tch cc phn t hu hn, Tnh ton ng hc v ng lc hc c cu. Cc phn mm ny c hng lot cc u im sau: Gi thnh r hn nhiu so vi cc h tch hp Vic khai thc cc tnh nng ca chng tng i n gin Khng i hi cu hnh ca my tnh cao Chnhvnhngldonychngcavosdngkhrngri.Tuy nhin cc phn mm loi ny cng c mt s cc hn ch sau: Domiphnmmchthchincmtchcnngtrgip,nn thc hin ton b quy trnh t thit k n ch to mt sn phm ta phi s dng nhiu phn mm khc nhau v yu cu cc phn mm ny phi c tnh tng thch cao c th trao i d liu mt cch d dng Do khng dng chung mt c s d liu nn cc vic cp nht cc thay icamtkhubtktrongqu trnh to ra sn phm tng i kh khn. Cchnchnycahphnmm"BestinClass"scgiiquyt bng cc h thng tch hp 2. Cc phn mm tch hp 125Ccphnmmtchhpchnhthnhbiviclinktnhiumul khcnhautrongmththngthng nht. Mi m ul thc hin mt cng on ca qu trnh thit k - ch to. Trongnhngnmgnycc h thng tch hp c nhiu nh thit k - ch to hng u trn th gii quan tm v a vo s dng nh cc l do sau: Cchthngtchhpdngchungmtcsdliutoiu kin cho vic nhanh chng cp nht cc thay i Mt trong nhng u im ni bt ca cc h tch hp l kh nng kim tratngthchcaccchititthitktrongmtkhilprptng th v thc hincc hiu chnh nu cn thit Vit nam, trong nhng nm gn y cc phn mm tr gip trong thit k -chtocbitnvavopdngccmckhcnhau.Tuy nhin cc phn mm ny ch yu thuc nhm " Best in Class " vi cc tnh nng tng i hn ch v d nh: TronglnhvcthitkhnhhcAutocadcaAutodeskca vosdngkhrngritrongnhiulnhvckhcnhaunhChto my,Xydng,Kintrc...Tuy nhin Autocad ch hn ch mc araccbnvphngvinnchng,cnkhnngxydngm hnh khng gian ca n cn rt nhiu hn ch Trong lnh vc phn tch cc phn t hu hn, cc phn mm khc nhau nh SHAP 90, ANSYS ... cng c nhiu ngi bit ti PhnmmALASKA ca c c a vo s dng kh rng ri cc vin nghin cu v trng i hc trong c nc, c bit trong lnh vc phn tch ng hc v ng lc hc ca c h nhiu vt Cchtchhpmcdcnhngtnhnnghtscmnhmnhngvn cn ht sc mi m i vi chng ta. Trong s cc h thng tch hp khc nhau trn th gii, CIMATRON c bit n nh l mt trong nhng h thng thnh cng nht: CIMATRONlhthngtchhpcscnhtcdngtronglnhvc thitkvgiacngckhdonhmchuyngiacaNhtvIsraelhptcxy dngtnm1990.NniktCAD-CAMthnhmththnghonchnh, ngoi ra CIMATRON cn cho php chng ta to ra m hnh cc phn t hu hn tmhnhhnhhcdngctrongCADdngtrongvictnhtontrng thi vt l ca chi tit v d nh: tnh nhit (tnh ton qu trnh truyn nhit, ng sut nhit),tnh bn ...Ton b h thng Cimatron bao gm bn Modul: 126 CIMATRON - MODELING CIMATRON - DRAFTING CIMATRON - FEM CIMATRON - NC Toramtchutrnhtchhpkhpkntrgipchngtatrongccbc khc nhau ca qu trnh Thit k - Gia cng : 1. THIT K Trong lnh vc thit k m hnh, Cimatron cung cp cho chng ta cc cng c hiu qu xy dng cc kiu m hnh hnh hc khc nhau nh: M hnh khung dy ( Wire - Frame ) M hnh b mt ( Surfaces ) M hnh th c ( Solid )Vicccngcny,chodbnlmvicviccmhnhkhungdy,b mthocmhnhthc,Cimatronchophpbnxydnghunhttc nhnggmbncthtngtngra.Lmvictheotrnhtttrnxung hoctdiln,saochophhpnhtivicngvicangthchin.Tnh thng nht ca cc php ton l gc, mt giao din ho trc quan v mt c s d liu dng chung xc tin vic chun b cho vic gia cng m hnh ca bn M hnh khung dy v b mt Mhnhkhungdyvbmtcacimatroncungcpyccphnt hnh hc bao gm c cc mt Bezie, Gregory v Nurbs. To ra thm ch c cc b mtiukhcphctpmtcchddng.Cclnhthitk,mtbcngc mm do, mnh m v ton din cha ng c nhng php pha trn tinh xo, v trnvcttanhiumt.Mtslnglncccngcthmtravhiuchnh cho php cc thay i nhanh chng v m bo mt chnh xc tuyt i. M hnh th rn Vicmhnhhobngphngthckhithuctnhcsthitkc nhng m hnh t do v trc quan. Hthngshngdnbn mt cch trc quan, t ng gi ra cng c v phctrongkhihinthra mt cch thch hp cc ng tr gip thit k bt cc i tng hoc nhc bn khi i tng vt ra hoc bn trong cc rng buc. nhnghacc rng buc khi bn v phc, hoc thm vo n sau ny. Bn lun duy tr c mt s kim sot mt cch hon ton cc mi quan h thng s vi kh nng thay i bt k thi im no. 1272. DNG BN V Cimatron Draft c thit k m rng ti a cht lng ca bn thit k c kh. N cung cp cc bn v mt cch nhanh chng v thng minh, trong khi vn duy tr cc mi quan h vi m hnh hnh hc Cc hnh chiu v hnh chiu ring phn c chiu t ng t m hnh 2D v3Dcabnbtkmtgcchiunombnmun.Cchnhchiuc ni kt vi m hnh c t ng cp nht khi m hnh b thay i. d dng to raccbnvphchpchangnhiuhnhchiu,mchngcthxpxp thng hng vi nhau v hiu chnh mt cch ring r. Tt c cc kch thc, dung sai, mt ct, ch thch c th c hiu chnh m khng cn nhp li cc d liu a vo trc 3. TRONG LNH VC TNH TON PHN TCH ngdngFEMtrongCimatronlcngcgipchngtaphntchtrng thi vt l ca chi tit thit k, qu trnh ny c thc hin qua 3 bc: Pre-Processing (Tin s l ) Analyze ( phn tch ) Post - Processing ( qu trnh hu s l ) Trong Cimatron s tr gip chng ta trong hai bc phc tp nht l bc tin s l v hu s l. Pre-Processing Trongqutrnhphntch,tnhtonbctinslthcchtlvictoram hnhccphnthuhn.ybmtcamhnhhnhhcscchiara thnhliphnt,cc khi th c s c phn ra thnh mt s ln cc phn t,Ngoilc,vtliucngnhcciukinbinrngbucscgncho mhnh.ylmtcngvichtsctmvmtthigian.Tuynhintrong CimatronFEM,hunh mi vic c thc hin mt cch nh nhng v nhanh chng: TrncscamhnhhnhhctodngtrongCIM-Modeling,vicchia cc phn t c tin hnh mt cch t ng theo mt chnh xc yu cu, h thng s t ng tnh cho ta c to cc im nt. Hthngcungcpsncho chng ta mt th vin cc loi phn t, vt liu, cc kiutcdngcangoilcchngtacthddnggnhoctchngln m hnh. 128CIMATRONMODELING DRAFTING CIMATRON-NC CIMATRON-FEMPRE-PROCESSINGPOST-PROCESSINGSOLIDWIRE-FRAMESURFACESANALYZECSDL Hnh 3.1. S tng quan cc chc nng ca Cimatron Ngoiracckhnngsauycacngcbintptrong Cimatron - FEM cho php ta t c mt li ti u cc phn t: Ni t ng hoc trc quan cc im nt Trn, nhp cc li c mt khc nhau Thayivtrccimntcngvivictng cn i cc phn t lin kt vi im nt . Thayivtr,saochp,xo,xoaybtkmtphnnocali c to ra. Post - Processing 129Chophpchngtahinthccktqutnhtonkhcnhaunhngsut, nhit,bindng,phnlc,Gradientngsut....ychngtacthla chn: Kt qu a ra dng s hay ho Hinthringhayngthimhnhbbindngvmhnhnguyn thu La chn cc mu sc v t l xch khc nhau d dng quan st Nuktquaradngho,tacthlu li n di dng mt tm nh d dng c th s dng li n khi cn phi so snh cc kt qu khc nhau trong qu trnh hiu chnh, ci tin m hnh Mhnhhnh hc v m hnh cc phn t hu hn c th c hiu chnh ngaytrongPost-Processing.Nhvyvistrgipcacccngcm Cimatroncungcpchngtahontoncthkimtraccktqu tnh ton, c lp c cc vng nguy him, a ra cc hiu chnh cn thit v thng qua c s d liu dng chung cp nht kp thi cc thay i.4. GIA CNGTrongnncngnghipkhngcgccoilhinnhin,tuynhin Cimatronlmtngoil.Ccthaotctrctiptrncsdliucam hnh thitk,CimatronNCtoramtngchydaochnhxcchobtkmtb iukhinsqutrnhgiacngno.Ncungcpmtgiiphptondincho cc my tin, phay, khoan, dp v my ct xung in t 2.5 n 5 trc. Cng c qun l cc ng chy dao cung cp kh nng kim sot mt cch tng th vic to ra, thay i v hin th tt c cc thao tc NC. Vinhngctnhtindngvscmnhcamnh,mcdyucucc cu hnh v phn cng kh cao: Ti thiu l my 486, b nh trong 16 MB , Card mn hnh 1MB, khng gian t do trn a cngln hn 150 MB , gi thnh ca phn mm kh t,nhng ch sau mt thi gian ngn h thng phn mm ny c cc cng ty hng u trn th gii s dng. Theo s liu thng k ca hng SEILO, khong 85 % sn phm ca ngnh cng ngh cao c to ra bi s tr gip ca CIMATRON. 3.1. Giao din ca CIMATRON 3.1.1. Mn hnh ho ca Cimatron MnhnhhocaCimatronkhngnhnggipchngtaddngthc hin cc lnh khc nhau m cn cung cp cho ta cc thng tin khc nhau v ch 130 lm vic hin thi v nhng thng bo, cc dng nhc trc tuyn m mn hnh cung cp s ch dn cho chng ta bit cn phi lm g bc cng vic tip theo. CckhilnhcaCimatroncbtrtheocutrchnhcymtad dngtipcnvinthng qua chut cng nh bn phm, Mn hnh ho ca Cimatroncchiaramtsvngthchinmtchcnngxcnhnhtrn hnh v : 1. Dng nhc (Prompt Area): TrongkhithchincclnhcaCimatronvngnylunhinrali nhc, hng dn ngi s dng phi lm nhng vic g trong bc tip theo. i khivngnyxuthinccdngnhcmtviclachnccthngs, phngn,trongtrnghpnytaphithayicclachnkhicnthitv sau n EnterVng trngthiDng hng dnVng quan h Dng nhcDr af t i ngNot eEXITUNDOVng cc hm thamchiu tc thiCc hm ca ng dnghin thiCc hm dng chung Hnh 3.2. Cu trc giao din ho ca Cimatron 2. Vng quan h : Vngnyhinracclachn,ccthamshnhthccalnhangthc hin 3. vng trng thi:131Thngbomtstnhtrnghinthicabnvnh:phngphpxc nh im (END, SCREEN, MID, ...), Mu sc ca nt v, lp hin thi ... 4. Vng hm s (bng iu khin) Bng iu khin nm bn l phi ca mn hnh cha cc lnh dng trong Cimatron, bao gm cc vng sau: Cchmtruyxuttcthi:gmnhnghmdngiukhinmn hnh, cc lp ca bn v. cc hm ny c th c gi bt k thi im no khi m h thng ang trng thi ch tn hiuiu khin t chut Vngngdnhinthi:c3phmhinthngdnghinthi,hm ang thc hin v la chn (option) ang c thc hin. Vngcchmngdngring:vngnyhinratncacchm Cimatron mt ng dng xc nh. Do khng gian b hn ch nn ch mt phn tn cc hm ny c hin ra hin th phn tip theo hoc phn pha trc ca danhschtnhmtadngchcnngvchcnngcachut.hinth ton b danh sch tn hm ca ng dng ang hot ng tadngchcnngcachut.Cchmnychcthtruyxut c khi li nhc xut hin. Vngcchmhthngdngchung:nhmhmnybaogmcchm dngqunlviukhin,cchmnychungchottc cc ng dng ca Cimatron v c th tip cn c khi xut hin li nhc 5. Vng v: l vng dnh cho vic hin th cc i tng v v ta khng th tip cn c vng ny khi mt menu no xut hin vng quan h 6. Con tr :Mc nh n l mt du cng v xut hin ch trong vng v. ta c th thay i hnh dng ca con trnh lnh DISPLAY 7. Dng thng bo:Nmphndicamnhnhvthngxuynaraccthngtintr giphocboli.trongngdngNCysxuthin2dngthngbovto hin thi ca dng c ct v tc , tn dng c ct. 3.1.2. S dng chut trong Cimatron Cimatronsdngchut3phmvnlthitbchyuthchincc thaotcvcng nh la chn cc hm v Option ca n. Trong Cimatron ta c th s dng tng phm chut mt cch ring r hoc phi hp chng vi nhau: 132Phm tri chut : Thc hin cc chc nng sau: La chn cc hm v Option ca hm, Ch ra mt v tr xc nh trn vng ho Chn cc i tng v (Entity) Phm gia ca chut: Thc hin chc nng thot (Exit) trong cc tnh hung sau: Kt thc vic chn cc i tng v thc hin bc tip theo Thotkhilachnhinthivtrvbcutinhoc bc trc ca hm Thot khi hm hin thi Phm F5 c chc nng tng ng phm gia Phm phi chut: Thc hin chc nng trong cc tnh hung sau: Gi cc menu con lt trang tip theo khi c mt danh sch di Phm tri kt hp vi phm gia: Thc hin chc nng : Hu b thao tc va thc hin v tr v trng thi trc Cun ngc, v d nh hin th ra mn hnh danh sch trc ca cc hm trong ng dng hin thi Phm F6 c chc nng tng ng. Phm gia kt hp vi phm phi : Dng gi cc hm truy xut tc thi. Phm F8 c tnh nng tng t. Phmtrikthpviphmphi:DnggiMenuiukhinch mn hnh nh sau: INDICATE & EXITINDICATE/CROSS/MARK/CLEAR PICKCROSS-HAIRNO MARK Nhng la chn ny rt tin ch cho vic trnh by vng ho ca mn hnh m khng phi chn bt c mt hm no y: NIDICATEch ra mt im mt v tr bt k trn mn hnh PICK chnv lm sng i tng, CROSS hin th con tr dng du ch thp CROSS- HAIR Hin th con tr ging nh hai ng thng giao nhau 133 MARK To ra cc chm im ti im m ta nhy chut NO-MARK khng to ra cc chm im CLEAR xo tt c cc du chm im to ra trong qu trnh v Phi hp c 3 phm chut :S hin th danh sch tt c cc hm c trong ng dng hin thi 3.1.3. Bn phm TrongCimatronbnphmcdngnhpccdliu dng k t hoc shoctip cn v sa i cc tham s hnh thc. i khi bn phm cng c dngthchincclnhkhcnhaukhichut khng hot ng. Thm vo mt s phm c cc chc nng c bit sau: Ccphmmitndngdchchuyntrongmnhnhcngnhgia cc hm trong danh sch cc hm. y cc phm ny c th dng thay chc nng ca chut Phm xo li (Back space) dng xo mt k t v pha trc PhmENTERdngktthcvicnhpccdlius/chvkhng nh mt thao tc no CTRL gi chc nng nh 1 phm iu khin v lun c phi hp vi mt phm khc CTRL+BgitinchCOLORSETUP,chophpxcnhmuca cc menu v i tng v CTRL + D xo im, ng thng, ng trn hoc b mt va v xong khi m hm dng v chng vn cn hot ng. khong 100 i tng v c th xo bng cch ny CTRL+Fdnglmtitonbmnhnh,chcnngnykhng dngc khi h thng ang chnhp vn bn CTRL + Gto ra GIF file t ton b mn hnh hin thi. File ny s c phn m rng l GIF CTRL + X ngng hot ng ca hm hin thi ESCthotkhihmanghotngvtrvlinhc F10 thot tm thi khi Cimatron v v DOS. tr li Cimatron ta g EXIT 134 Phm bc trng chn hm hoc cc Option ca n, y n c th thay th chc nng ca phm tri chut. 3.2. Xy dng m hnh b mt trong Cimatron 3.2.1. Trnh t tin hnh xy dng m hnh b mt m bo cht lng cng nh tc to dng m hnh, trnh cc sai st vcngtrnhphithchincccngvic v ch. Sau khi nhn c nhim v thit k chng ta phi tin hnh thc hin theo cc bc sau: Phntchktcucabnthitk,xcnhccbmtcncto dng cng nh cc thng s v yu cu cht lng ca cc b mt , Lachnkiubmt,cclnhcaCimatronvcctuchncan dng to dng cc b mt cn thit k, Phn lp bn v, Dng khung bn v, cc h quy chiu v cc ng c s, Tin hnh to dng cc mt c s, Tin hnh hiu chnh, sa i nu cn thit, Kim tra cht lng ca tng b mt v kim tra tng th bn thit k. 3.2.2. Cc nguyn tc chung khi chn la cc b mt Cimatroncungcpchochngtamtslnglnccloibmtkhc nhau, chnh v vy trong bc chun b, trc khi bt tay vo v chng ta phi t t ra cc cu hi: Loi b mt no s c dng xy dng m hnh ? Lnh no v ty chn no s c s dng ? ykhngchcmtcutrliduynhtchocccuhiny,vicla chnnyhontontuthucvothiquencngnhkinhnghimcangi thit k. Tuy nhin tn ti mt s nguyn tc c bn sau nh hngcho vic la chn: Tu thuc vo cc thng s m bn c, bn hy xc nh lnh no v tu chn no s ph hp vivn m bn cn gii quyt Sau khi chn s b ( bc trn), bn hy nghin cu tnh cht ca mi bmtvxcnhxembmtnolthchhpnhtvhytorab mt 135 Kim tra xem liu c cn phi thc hin cc thao tc b tr vi lnh ct xn (TRMSRF) Nu tn ti nhiu gii php cho vn t ra, bn hy xem xt cc gii phpcthkhc,sosnhchngtrnmnhnhtrckhiaramt quyt nh cui cng Nubntmracngmtlcnhiugiiphpchoktquttvkhng gii php no t ra tri hn, hy dng gii php n gin nht.Vdnh:toramtbmtnmgiahaingcong(Section)m khng cn quy nh dc ca n theo hng ca ng Cross-Section, th vic sdngmtk(RULED)stthnnhiusovidngmtBLENDvitu chn FREE - SLOPES. 3.2.3. Cc b mt c s c th c to ra trong Cimatron Nh phn tch cc phn trc, sc mnh ca phn mm Cimatron l n cung cp cho chng ta mt s lng ln cc loi b mt, tin khai thc cc kh nngcaCimatron,trongphnnychngtisgiithiumtcchtngquan cc loi b mt m Cimatron cung cp cng nh phng thc to ra chng: 1. B mt k (RULED SURFACE) ylloibmtctorabiviccunmtngthngmtcch trn tru dc theo hai ng cong Section tng i vi cc im ni. Kt qu l bmtnhncc cc ng Cross-Section l ng thng. Hng U s dc theo Section, hng V s dc theo Cross - Section ( l cc ng thng ). Hnh dng ca cc ng Section sthay i mt cch tuyn tnh t ng binthnhtsangngbinthhai,khingcsthhaibinthnhmt imtacmtnn.Mttr,mtnnctcnglnhngtrnghpringca mt k toracbmtnytaphidngchaingcs(Section) sau dng lnh RULED v ch ra 2 ng c s ny (Xem hnh v) 136Chn ng cong 2Chn ng cong 1 Hnh 3.3. Phng thc xy dng b mt k TrongCimatrontacncthdngcmtmtk nm gia mt ng csvmtmtcongbngcchnhnghangcs,hngchiuxung mtcong, hoc ng c s v hng m cc ng sinh hp vi mt cong, l nhng tnh hung thng xy ra khi to dng cc b mt c quan h tng i vi nhau. Tu chn TRIM ON/OFF cho php chng ta c th xn b hoc khng cc phn tha ra ca b mt, lm tng tc to dng m hnh 2. Cc b mt trn xoay (REVOLUTE SURFACE) ylccbmtctorabivicxoaymtngcong(hocmt ng chu tuyn)i mt gc nht nh quanh trc xoay. Cc ng cong ny l ccSection(hngV)cabmtcnCross-Section(hngU)lcccung trn c tm nm trn trc quay. torabmt ny ta ch cn s dng lnh REVOL sau ch ra ng section v trc quay 3. Cc b mt cun ( DRIVE - SURFACES ) ylccbmtctorabivicdchtrtmtngcong(hoc chutuyn)dctheomtngcong khc hoc dc theo hng c quy nh bi ng cong khc.HngUcabmtlhngdctheongcongtrt(Section)v hng V ca b mt l hng ca cc ng nh hng ( Cross - Section ) Lnh to ra cc b mt ny ( DRIVE ) cha rt nhiu tu chn, cc tu chn cancthphnralmhainhmtheonhnghatonhccaccbmt c to ra: 137 SdngtuchnPARALLELSEC.(ccngsectionsongsongvi nhau), ta s nhn c DRIVE SURFACE Nusdngcctuchnkhctasnhncccbmtkiu BEZIER (xem gii thch phn sau ) 4. Cc b mt kiu BEZIER Cc b mt BEZIER v GREGORYcho php m t nhng kt cu ht sc phctptrongccngnhcngnghiptvcngnghiphngkhng.Ccb mtnycrtnhiuuim,cbitlchngddnghiuchnhvddng thchinccthayiccb.Rtnhiulnhtodngvhiuchnhtrong Cimatron c th to ra nhng b mt ny. MtBEZIERbaogmmtchuiccmnhnivinhau,mimnhc nhnghabng16imiukhin.Hnhdngcaccmnhphthucvo v tr ca cc im ny. 12 im nh ngha 4 cnh bin ca mnh, trong ch c 4 imnmgclnmtrnbmtcnccimkhckhngnmtrnbmt m ch gy nh hng n hnh dng ca cc mnh. TrongbmtBEZIERSniktccmnhkhngnhtthitphitrntru v n c th c cc gc nhn bn trong b mt. iu kin trn tru ca hai mnh k nhau l 3 im iu khin sau y thng hng: mt im bn trong, mt im nm trn cnh bin v im th ba nm bn trong mnh k cnh (c ba im phi nm trn cng mt hng ng thng s) Ktcuccmnhcnhnghabngccimiukhinchophp chng ta d dng thc hin cc thay i cc b trn b mt. Cutrccacc mnh v tt nhin c b mt c th thay i bng vic s dng lnh MODIFY nh sau: Di chuyn cc im iu khin ( ngoi tr 4 im nm trn cc gc ) bng lnh MODIFY POINTS nhnghalidcccngbaoca b mt ( MODIFY SLOPES ). Cc dc ny c th c nh ngha nh sau: - dc dc theo mt ng bin l hng s ( CONSTANT ) -dcdctheomtngbinsthayituyntnhtunysang u kia ( LINEAR ) - dc dc theo mt ng bin ch nh ca mt b mt l cc tip tuyn vi dc ca mt cnh ca b mt th hai ( SURFACE ) 138-dctimiimnt(imnmtrngccaccmnh)dctheo ng bin ca b mt c xc nh ( GENERAL ) TtcccdngbmtkhcnhauucthchuynthnhmtBEZIER bnglnhMODIFY/APPROX.TOBEZIER.Bnglnhnyvivicsdng hp l gi tr ca chnh xc chuyn i ta c th gim bt c mc gn sng ca b mt nguyn thu. 5. B mtGREGORY B mt GREGORY l s m rng nng cao ca b mt BEZIER, n c tt cccctnhcamtBEZIERtuynhinkhcvibmtBEZIERnlun lun trn tru. Mi mt mnh ca b mt c nh ngha bi 20 im iu khin, 12imnhngha4cnhv8imbntrong.Hnhdngcaccmnhny phthuchontonvoccimiukhin.4imiukhinbntrongs m bo c s trn tru giacc mnh . BngvicsdngMODIFY/SMOOTH,tacthchuynmtbmt khngtrntruthnhbmtGREGORYtrntru,tuynhiniunyskhng thchincnu b mt nguyn thu c im bt thng hoc s chuyn i s to ra mt thay i r nt ca b mt nguyn thu. CclnhtobmtkhcnhaunhDRIVE,BLEND,RULED,MESHv COMSRF,nunhbmttorakhngtrntru,nstngcchuyn sang mt GREGORY6. B mt pha trn BLEND SURFACE ylmtbmtctorabi mt chui lin tip cc ng cong, v (hoc) cc im, v ( hoc ) cc ng bao ca b mt. Kt qu nhn c l mt mt BEZIER, cc b mt ny lin tc v c th trn tru. Khi chn cc ng bin cabmt,mtngcongngmnhsctoravscxoingay sau khi b mt BLEND c to ra. torabmtnychngtadnglnh BLEND sau ch ra cc ng Section m n cn phi i qua. 7. Mt li - MESH SURFACE ylmtbmtcnhnghabimtchuiccngSectionv Cross - Section. B mt to ra l mt li cc mnh nh. Bmtiquamt cch trn tru mt chui cc ng Section ( hng U ) v cc ng Cross - Section ( hng V ) MimtcpccngSectionvccngCross-Sectionknhaus to ra mt mnh b mt 139S tip ni gia hai mnh k nhau l lin tc v trn tru Bn trong cc mnh, hnh dng ca b mt c nh ngha bi mt hm s tuthucvohnhdngcaccngcongtoramnhvkhong cch t im ang xt ti cc ng bin ca mnh torabmtlitadnglnhMESHsauchrahainhmng cong ct nhau: BccngcongcchnutinstonnccngSection,cn nhm ng cong chn th hai s to ra cc ng Cross - Section Thuttontoramtlichophpchngtatoranhng b mt c hnh dng tng i phc tp v t c quy lut 8. B mt NURB SURFACE ylbmtccutrcphctp,ctoratmtmatrnccim nmtrnhngSectionvCrosssection.Ccimnycvaitrnhnhng im iu khin to nn cc ng Section v Cross - Section. BmtNURB(Non-UniformRationalB-SplineSurface)chophp chngtanhnghamcnhhngtngichomiimiukhinkhi b mt c to ra v ta cng c th cp nht n sau ny khi cn hiu chnh CcngSectionvCross-Sectioncnhnghabiccimiu khinlnhngngcongdngNURB(Non-UniformRationalB-Spline). Bc ngoi suy ca cc ng cong ny cng c th thay i. u im ni bt ca cc mt cong ny l d dng thay i hnh dng ca b mtkcccthayiccbnhvicthayivtrcngnhmcnh hng ca cc im iu khin ( dng lnh MODIFY/ POINTS) tora c cc b mt ny ta dng lnh NURB sau ch ra cc im iu khin vi lu rng : S lng cc im iu khin trn mi pha phi ln hn s bc ca a thc ngoi suy. 3.2.4. S dng cc cng c hiu chnhCimatroncungcpchochngtahnglotcccngchiuchnhsa i cc b mt c to ra: 1. Lnh ct ta cc mt cong ylcngc ht sc tin li lm tng tc xy dng m hnh: sau khi ccccbmtcstadnglnhcttavi tu chn ( TRIM ) loi bt nhng phn tha v my s t ng tnh cho tc cc giao tuyn vi chnh xc yu cu. Ngoi vic ct ta y chng ta cn c th chia mt b mt thnh 140nhiu phn ( S dng tu chn DIVIDE). iu ny ht sc cn thit khi ct xn cc b mt phc tp vi cc php tuyn i du thchinviccttacngnhchianhccbmttadnglnh TRMSRF. Lnh ny ngoi vic c hai tu chn l TRIM v DIVIDE nh trnh by trn, n cn c cung cp cho ta nhiu phng thc ct ta khc nhau: - PLANE : ct ta ( hoc chia mt b mt) bng cch ch ra mt mt phng ct qua b mt -SURFACE:ctta(hocchiamtbmt)bngcchchramtbmt khc ct qua b mt , y ta c th la chn hoc xn c hai b mt hoc xn b mt th nht -PARAMETERcthocchiamtbmtbngccngSectionhoc Cross - Section ch nh -CONTOURSChiahocctmtbmtbngcchchramtngchu tuyn, ng chu tuyn ny c th nm trn b mt hoc khng (khi mt cong s c chia, ct bi hnh chiu ca n ln b mt Saukhitinhnhchia,cttacthddngnhnlibmtbanu bng cch dng tu chn ORIGINAL. Ccobkhotbilnhnycthcphchibngtuchn CANCEL CONTOURS Cc b mt c s sau khi b ct ta u chuyn sang mt loi b mt vi tngilTRIMEDSURFACES,khcviccbmtbnhthngccbmt nycthcnhiuhn4cnhbin.thuntinchovicthc hin cc hiu chnh khc trn cc mt ny trong mt s trng hp Cimatron cho php chuyn i chng thnh mt cong bnh thng ( xem lnh Modify ) 2. To ra cc mt ln ni gia cc b mt Thngthngccbmtcachititthngnivinhaudimtcung lnno,tuynhinkhixydngmhnhbmttrongCimatrontakhng cn phi to dng chng nh lm i vi cc b mt c s: Sau khi c cc bmtcstachcnthchinlnhFILLETvcungcpchomyccthng tin cn thit bao gm: Ch ra cc b mt giao nhau m gia chng mt ln s c to ra Xc nh bn knh cung ln Ch ra cc hng xc nh tm ca cc cung ln 141Trong lnh v trn ny ta cn c th la chn TRIM ON khi mun cc phn tha ca hai b mt c s c xo b hoc TRIM OFF khi mun gi chng. tng tc v trn Cimatron cung cp cho chng nhiu tu chn v trn khc nhau : - 2 SURFACES : to ra mt ln gia hai b mt giao nhau -3SURFACES:toramtlngia3bmtgiaonhautngimt, trong trng hp ny gc ca ba mt c s s c to ra mt mt li ni trn tru cc mt ln v mt c s -3DIF.RADI:chophptorabamtlnviccbnknhkhcnhau gia ba mt c s ct nhau -MULTI.:toraccmtlnnmgia mt mt y v nhiu mt thnh ct mt y ny 3. Cc cng c tr gip vic nng cao cht lng b mt ca m hnh Vic nng cao cht lng b mt, m bo s ni lin tc, trn tru ca cc b mt c s l mt cng vic ht sc quan trng. N quyt nh n cht lng, thm m ca sn phm cng nh trnh c cc li pht sinh trong qu trnh gia cng chi tit sau ny.Viccithinchtlngcaccb mt v s ni kt trn tru gia chng c thc hin bi lnh MODIFY, n cung cp cho chng ta rt nhiu kh nng hiu chnh: Khi chng ta mun chuyn mt b mt bt k thnh mt BEZIER, to iu kinddngchovicthchinccthayikhcnhau,hysdngtuchn APPROX. TO BEZIER kimtraxemmtbmtctrntrukhnghocchuynmtmt BEZIER khng trn sang mt GREGORYtrn tru, ta dng tu chn SMOOTH, tuy nhin cn phi lu rng tu chn ny khng thc hin c trn nhng b mt c im bt thng hoc nhng b mt m chuyn i thnh trn tru s l thayimtcchrntn.Trongtrnghpnytaphitinhnhthchin thm cc hiu chnh khc trc khi thc hin tu chn SMOOTH Tu chn FAIR dng gim bt cc gn sng ca b mt Trnghpbnmunkimtrato,thayivtrhocmcnh hngcaccimiukhintrongccmtBEZIERhocGREORY,hys dng tu chn MODIFY POINTS142Khivic ni kt ca cc mt k nhau khng trn tru, chng ta thng phi thay i dc ca nhng b mt ny dc theo ng bao chung ca chng bng tu chn MODIFY SLOPES ( xem thm phn b mt BEZIER trn ) TuchnSURFACEEXTENSION cho php ko di mt cch tuyn tnh mt b mt ti mt cnh ch nh bng cch tora mt mt kvi chiu di yu cu 4. S dng VERIFY/ SURFACE MtntcocaCimatronlchophphiuchnh,kodn/thungn ccbmtctorabngccthngscabmt.Nhchngtabit mi b mt c c trng bng cc phng trnh tham s vi hai tham s U v V theo phng ca Section v ca Cross - Section:X= F1(U,V), Y= F2(U, V),Z= F3(U, V), Trong nhiu trng hp thun tin cho vic s dng cc gi tr ca U v V c quy chun trong khong ( 0, 1 ), c ngha l: Start U=0, End U=1; Start V=0, End V=1 DnglnhVERIFY/SURFACES/SURFACEDATAtacththmtra c cc gi tr ny ca b mt, trong trng hp mun ko di cc mt cong v phatrctheophngUhocVtacththayichoccgitrStartU1.Trongmtstrnghpsaukhithayiccbmtnumuntrvb mt nguyn thu ta cng c th dng lnh ny 3.2.5. Cng c tr gip ca Cimatron CccngctrgipmCimatroncungcplmchocccngvicxy dng m hnh c thc hin mt cch d dng v nhanh chng. Cc cng c tr gip bao gm : 1. Lp v (LEVEL) Lp v l tp hp cc i tng v ca mt bn v c cng mt thuc tnh. VicphnlplmtkthuthtsccocaCIMATRONcngnhcc phnmmCAD.Mtbnvphctpthngcphnthnhnhiulpring bitchaccphnngincabnvvnhvyvicvtrongmilpc thchinhtscngin.Saukhicttccclpvchcnxpchng kht chng ln nhau ta s nhn c bn v yu cu, v nh vy cng vic v s 143tr nn ht sc n gin. Ngoi ra lp v cng cn to iu kin cho chng ta d dng hiu chnh, in n. Khi bt tay vo xy dng mt bn v phc tp chng ta phi tin hnh phn lpccitngvcubnv.Mtbnvcrtnhiucchphnlpkhc nhau, n tu thuc vo kinh nghim cng nh thi quen ca ngi v. Tuy nhin sdngchiuqucclp,vicphnlpphiatrnccnguyntc sau: - n gin ho : c ngha l cc nt v trn mi lp phi khng qu chng cho, m bo c th v chng ra d dng -Tnhctrng:Mintvphictrng cho mt phn nht nh ca bn v, khng nn chia bn v ra qu nhiu lp -Tnhthngnhtvchnhxc:Cclpcphnrasaochokhiv ring tng lp vn m bo c v tr tng i ca n trong bn v tng th iviccmhnhviccbmtphctpchngtacnphitorat nht cc lp sau: Mt lp tham chiu nh v cc b mt Mi b mt nn t trn mt lp ring r Ccngthng,congdngnhngha mi b mt cng nn c v trn mt lp ring Thng thng khi lm vic vi cc lp v chng ta phi thc hin cc thao tc sau: To ra mt lp v mi Gn, thay i thuc tnh ca lp v a mt lp v tr thnh hin thi i tn lp v Chuyn cc i tng v t lp ny sang lp v kia CcthaotcnyhontoncththchincddngtrongCimatron vi vic s dng lnh LEVELS, lnh ny c cc la chn chnh sau: ACTIVEThay i lp hot ng hoc thm vo cc lp mi DISPLAY Hin th mt cch c la chn cc lp c 144 DISP. RANGE Hin th hoc khng hin th mt vng xc nh cc lp MOVEDi cc i tng c chn t lp ny sang lp kia COPYCopycc i tng c chn t lp ny sang lp kia RENAMEThay i tn ca lp DEFINEnh ngha cc lp mi m khng lm thay i lp hin thi PROTECTLm cho cc i tng v thuc lp ch nh khng th thay i c nhng vn c th tham chiu ti n PROT. RANGELmchoitngvthucvngchnhcacclpkhng th thay i c nhng vn c th tham chiu ti n COPY MASK Copy"LayerMask"tmtcassangcaskhc.Cclp cchuynsang"on"casnguncngcchuynsang "on" ca s ch DELETEXolpnunkhngchaccitngvvkhngphil lp hin thi LEVEL MAPHinthtncacclpcafilehinthihocmtfilebn ngoi 2. Cng c truy bt im Cng c truy bt im gip chng ta nhp c chnh xc cc im c v tr cbitsoviccitngvcmkhngcnphixcnhtoca chng, n lm tng mt cch ng k tc to dng m hnh. Khi my yu cu nhp im, gi ra menu truy bt im, ta ch cn n phm phi chut.Cimatron cho php truy cp ti cc im c bit sau: 145 SCREEN: imnhncslimgiaocamtphngvving thng i qua im ch nh v vung gc vi mn hnh Numtphngvvunggcvimtphngmnhnh,im nhncslgiaocangthngiquaimchnhv vunggcvimnhnhvi mt phng song song vi mn hnh v i qua gc ca h to vt th Nuchlitrnmnhnhcbtimnhncsl im li gn nht vi im ch nh END :imnhnclimcuicangcongcchn,gn vi im chn MID :im nhn c l im gia ca ng cong c chn CENTER:imnhnclimtmcangtrnhoccungtrn c chn PIERCE :im nhn c l giao ca ng cong c chn vi mt lm vichinthivphiagnviimchn.ngcongphi khng c song song vi b mt lm vic hin thi CLOSE :im nhn c s l mt im gn nht vi im chn v nm trn ng cong c chn PICK :im nhn c s trng vi im chn KEY IN :imnhncscxcnhbngcchgcctoca n DELTA : imnhncscxcnhbngcchnhpkhongbin thin to t im chn. y ngoi vic chn DELTA ta cn phi chn 1 Option khc dng xc nh im tham chiu 146 SURF:im nhn c s l giao im ca ng cong hin th b mt cchnvngthngiquaimchnvvunggcvi mn hnh SRF -B :imnhncsnmtrnngbaocabmtvgnvi im chn nht SURF-C :imnhncslimgcgnviimchnnhtcab mt SURF-X :im nhn c s l im giao ca 2 ng cong mn hnh gn vi im chn nht TP NOD :Chdngtrongngdng NC, khi TOOL PATH c m, im nhncslimcuicangchydaocchngn vi im chn FEMNOD :ChdngtrongngdngFEM,imnhncslimnt gn vi im chn UCSORG :im nhn c l im gc ca UCS hin thi. 3. Cc cng c iu khin mn hnh Cc cng c iu khin mn hnh cho php chng ta quan st v thao tc d dnghnvimhnhangtodng.TrongCimatroncccngciukhin mnhnhcthddnggirabtclcnobngcchnphmphi v phm gia chut. Cc lnh ny c chia lm hai nhm: a.Nhmlnhphngto-thunhbcnhtrnmnhnhcthddng quan st cc chi tit ca m hnh bao gm: W:Xcnhtlphngvvngmnhnhbngcchvramt ca s SCALE:Thayikchthchinthcaccitngvbng cch g vo t l phng 147 -Z+:Phngto-thunhvchratmmnhnhmibngcch nhy phm tri hoc phi chut Saukhithayitlphngtaluncthquayvhnhnhm ton b cc i tng v c a vo va kht trn mn hnh bng lnh AW b. Nhm lnh xoay bc nh trn mn hnh nhn c khung nhn mi: TrongCimatrontacthxoayccbcnhcam hnh mt cch trcquan hoc nhp cc gi tr gc xoay t bn phm ( ANGLE ). C th xoay m hnh quanh mt im xc nh ( ROTATE ) hoc quanh mt ng trc do ta nh ngha (AXIS) Cc bc nh sau khi c xoay, phng to - thu nh c th c ghi lidimttncthvta c th gi li n bt k lc no. Vic ghiliccbcnhvqunlncthchinbnglnh PICTURE 4. H to ngi dng Cc h to ngi dng gip chng ta d dng nhp cc im theo cc totngicngnhddngxcnh cc mt phng v hin thi khi to dng cc ng c s ca cc b mt.TrongCimatron,ngoimultodngmhnh(MODELING),ccm ul khc nh FEM, NC cng s dng cc h to ngi dng ring. Cc UCS c to dng trong MODELING c th c dng trong cc ng dng khc tuy nhinccUCScnhnghatrongccngdngkhcchcdngtrong ng dng . Victoravqunl cc h to ngi dng c thc hin bng lnh UCS. Lnh ny bao gm 6 tu chn: ACTIVE:Thayihtohinthihoc nh ngha UCS mi ng thi a n tr thnh hot ng CREATE : To ra UCS mi MOVE : Di UCS RENAME : Thay i UCS DELETE : XoUCS (hin thi khng hot ng) DISPLAY:ongctrngthimnhnhcacctrcto c chn 1483.3. S dng module NC. toracsdliuiukhinmyNCgiacngccchitittrongh thng CIMATRONchng ta phi gi ra m ul NC ca CIMATRON. Qu trnh NC trong CIMATRON c tin hnh qua nhiu bc nh hnh v: MACSYSTOOLSTOOL PATHGCODE POSTPRTECHNOLOGICALFUNCTION Hnh 3.4. Cc bc thc hin trong CIMATRON - NC 3.3.1. MACSYS:y l bc u tin ca qu trnh NC. Trong bc ny ta phi nh ngha mt h to my (MACSYS), thc cht l vic nh hng cho chi tit c xy dng phn Modeling. Hng ca trc Z lun phi trng vi hng ca trc chnh ca my gia cng v hng cu trc X, Y phi chn trng vi hng ca bn my. Nu ta chn cc hng ca trc khng hp l s khng th thc hin c cc th tc gia cng sau ny im gc ca h to my c th chn tu , tuy nhin to ca cc im dng trong cc th tc gia cng sau ny ( v d nh im cao nht, thp nht ca 149b mt gia cng, mt phng an ton m dao c th dch chuyn trn n khng va vo chi tit, to ca dng c ct mi thi im trong qu trnh gia cng ... ) u xc nh theo im gc ny. Chnh v vy ta nn chn chng sao cho sau ny d dng xc nh c to cc im thc hin cc thao tc khc nhau vi h to my ta dng lnh MACSYS : nh ngha mt h to my mi hoc gi ra mt h to my tn ti ta s dng tu chn ACTIVE ca lnh sau ch ra im gc ca h to my v hai im tip theo xc nh phng ca trc X, Y. Sau khi to ra mt h to my ta c th a ton b m hnh xy dngtrongMODELINGvotrongn, hoc ch a vo mt s b mt nhtnhcamhnhvo.Trongtrnghpmunathmmts i tng v ( ca m hnh xy dng trong MODELING ), vo trong h to my hin thi ta s dng tu chn APPEND i tn h to my ta dng tu chn RENAME TuchnDELETEdngxocchtomy cng vi tt c cc d liu to ra trong n 3.3.2. TOOLS Trongbcnychngtatinhnhnhnghaccthngscadaodng gia cng. Hy chn hm TOOLS nh ngha cc dng c ct, mt s lng khng hn ch cc dng c ctc th c to ra trong mt tp: 3.3.3. TOOL PATH bcnychngtaphitinhnhm mt ng chy dao (Tool path ). Mt ng chy dao bao hm mt chui cc th tc m n c gi ra khi nh ngha mt qu trnh gia cng. Mi mt th tc ( Procedure ) v d nh POCKET, PROFILE, SURMILL ... c to ra bng cch gi mt hm gia cng, cha ng ccdliumtccthuctnhhnhhctngng,ccthngsgiacngv cckhidchchuyncadao.Cckhidchchuyndaoclutrnh dng trung gian v c x l bng b hu x l to ra cc m iu khin my cho cc my gia cng xc nh 1. Cc iu kin cn thit to ra mt ng chy dao Chi tit:McdtacthtoramhnhhnhhctrctiptrongmulNC,tt nhtlchngtatorachngm ul Modeling. Cc i tng hnh hc c to ra trong NC ch tn ti trong MACSYS hin thi Dng c ct:150Mc d c th nh ngha cc dng c ct bn trong mt hm gia cng, tuy nhinttnhttahytoraccdngcctcnthittrckhimmtng chy dao. MACSYS:Trckhitorachuynngutincangchydao,cnphinh ngha mt h to my, chi tit gia cng, v cc dao ct cn thit nn c nh ngha trc khi gi cc hm gia cng tng ng. 2. To ra ng chy dao Vic m mt ng chy dao c th thc hin bng hai cch: Vicgibtkmtnhmhmgiacngno(MILL,LATHE, WIRE_EDM hoc PUNCH) s t ng m ra ng chy dao. SdngtuchnCREATEcalnhTOOLPATHtacthtora mt ng chy dao mi ca bt k dng gia cng no Ccngchydaotnticthcmralibnglnh TOOLPATH/ REOPEN Ngoi ra lnh TOOLPATH cn cung cp cho chng ta mt s tin ch khc qun l cc ng chy dao: RENAME: Thay i tn ca mt ng chy dao DELETE : Xo mt ng chy dao c Saukhingchydaoctorancthcnhnibng tu chnDUBLICATEcalnhTOOLPATH. Thc cht y l vic copy mt ng chy dao ang c m. Mtsccthtcctoratrong mt ng chy dao, nhng ta c thtmthichachyn.TuchnEXECUTEchophpchyttc cc th tc cha c chy trong ng chy dao hin thi Tu chn GLOBAL HEADER s to ra danh sch cc tiu ca tt c cc ng chy dao trong h to my hin thi Ngay sau khi mt ng chy dao c m ra, dng trng thi y mn hnh s cho ra cc thng tin v to hin thi ca dao, tn ng chy dao, cc thng s ca my v dao 3. nh ngha cc khi dch chuyn dao:Mtngchydaochangmtdanhschcxpxpccthtc. Vic chy cc th tc ny s to ra cc khi dch chuyn dao, mi th tc c th c nh ngha li v chy li. 1514. TECHNOLOGICAL FUNCTION ylphnchyucaquytrnhNC.ychngtaphisdngcc lnhgiacngmtcchhpltoraccthtctrongmtngchydao ang c m. Vic to ra cc th tc c tin hnh qua hai giai on: nh ngha th tc Chy n Vic nh ngha cc th tc c thc hin qua cc bc sau: Chnmthmgiacnghpl.Mimthmgiacngnys changmtsnhtnhccthngshnhhcvtuchn tng ng vi n Chnccitnghnhhcxcnhbmtgiacngvgi hn khng gian ca chi tit gia cng Cp nht cc tu chn ca lnh theo yu cu.Giai on ny yu cu chng ta phi nhp cc d liu tng ng. Ngay sau khi th tc c to ra, cc nh ngha xc nh chng c th c thay i nu chng ta mun Chy cc th tc: Cckhidchchuyndaoctoratngngviccnhngha th tc. Cc khi ny c th kim tra v hiu chnh bng tay v sau c gi sang bhusl.Giaionnykhngyucungidngnhpdliu.Chc nhngthtcviccnhnghahplmicthcthchin.Vicchy cc th tc c th b ngt bi ngi dng. Chng ta c th to ra cc nh ngha cho mt th tc v sau quyt nh chyhockhngchythtc.Nhngthtcchacchy(bbqua) hoc nhng th tc b ngt trong qu trnh chy c th c chy li cc bc sau ny. Vic chy li mt th tc trong mt ng chy dao ang m c thc hin bng tu chn RERUN cahm MANAG_TP. Trong qu trnh chy mt th tc ta c th dng li tm thi quan st v thay i cc ch hin th trn mn hnh bng cch n phm bc trng ca bn phm. Nhng th tc b ngt tm thi ny c th c chy tip hoc ngng vic chy ti im ngt. a. Cc hm gia cng ca Cimatron i vi my phay: 152Cimatroncungcpchochngtaycclnhiukhingiacngtrn my phay t 2 1/2 trc n 5 trc. Tuy nhin do thi gian c hn nn trong phm vi ti ny chng ti ch mi dng li khai thc cc lnh iu khin my 21/2 v 3 trc cc lnh ny bao gm: i vi my 2.5 trc: DRILL PROFILE POCKET i vi my 3 trc ngoi cc lnh dnh cho my 2.5 trc cimatron cn cung cp cc lnh sau: SURMILL SURCLR SRFPRF SRFPKT ZCUT WCUT CURVE_MX RULED_MX CLEANUP Lu : ivicchmPOCKET,PROFILE,WCUT,ZCUTcco khng c phay s to ra nu SIDE STEP ln hn ng knh chi tit i vi cc hm POCKET, PROFILE, WCUT, ZCUT , dao ct c th b hng nu DOWN STEP ln hn chiu di vng ct ca dao Khi cc trng hp trn xy ra, my s a ra cc li cnh bo DRILL : To ra chu trnh khoan cho my khoan Nhiu im khoan c th c nh ngha vi mt tu chn mt phng hay mt cong tham chiu. Trt t t ng hoc trt t o ngc u c th Cc im khoan c th thm vo hoc b i bt k thi im no. mi mtimkhoanhngcal,chlidao,chiusuctcthcnh 153ngha. Ngoi ra ta cng c th kim tra v sa i cc to im khoan v cc tham s khc Cc thuc tnh chnh bao gm: Chiu su khoan tnh theo ng knh ton b (BY FULL DEPTH) Chiu su tnh n nh mi khoan (BY TIP DEPTH) Chiu su tnh n ng knh ch nh (BY CHAMFER DIAMETER) Ch ra cc im chng vi mt tu chn xo chng Cc bc thc hin 1. Ch ra cc im khoan 2. Xc lp cc tham s hnh thc : Chnh xc ho, thm vo xo thay i v cp nht chiu su hoc kim tra cc im chng 3. Thc hin POCKET Torachuynngdaophaykhotvtliukhimtvngkhpkn nh ngha bi ng bao v cc o Ccngchutuyncththmvohocbtibtk thi im no. ivimingchutuyntacthnhnghaccgitrgcnghinghoc khong offset t cc chu tuyn Cc chuyn ng ca dao ti chiu su khng i v thc hin ti mi lp Z Nhiu k thut ct c th thc hin: Dctheoccngcongcchungbao.Ccdchchuyndao c thm vo ct vt liu tha im gc Dctheongthngsongsongdimtgcno,tacthchn ct mt chiu hoc 2 hng To hnh cc ng bin, vic tin v li c th c xc nh. Ngisdngcthnnhimtipcnbntronghocbnngoi vng khp kn, k thut RAMPING DOWN c th s dng, h thng s ti u ho cc chuyn ng gia cc vng; Thay cho vic li dao, dao s chuyn ng qua cc vng trc gia cng. Cc bc: Xc nh cc thuc tnh hnh hc 1541.hocnh ngha mt ng chu tuyn khp kn v nu cn thit c cc o, hoc nh ngha mt b mt phng 2. nh ngha khong offset v gc nghing ca thnh 3. Xc lp cc thng s hnh thc nu cn thit xc nh li hoc hiu chnh chu tuyn PROFILE To ra chuyn ng phay 2.5 trc ct dc theo mt cnh ca ng chu tuyn khp kn hoc h v cc b mt phng Ccngchutuynbtkdngnocththmvohocbtinu cnthit.ivi mi ng chu tuyn cc gi tr offset v gc nghing, hng phay c th c nh ngha, hiu chnh Chuyn ng ca dng c s nhng b su khng i v chia thnh tng lp Nhiu k thut ct khc nhau c th c s dng Ch ct mt chiu v hai chiu Ch CLIMB, CONVENTIONAL v ch ct phi hp S tin, li dao theo phng tip tuyn, php tuyn v ng phn gic mi lp ct cc vt ct nhiu pha c th c thc hin i vi gia cng th Kim tra ton b ngn nga va p vo cc chu tuyn Xn cc vng gy ra bi bn knh cong qu nh Xc lp cc tc chy dao khc nhau gc Cc ng cong kim tra c th thm vo hoc bt i nu cn thit Cc bc: 1. nh ngha c tnh hnh hc - Xc nh cc ng chu tuyn kn hoc h - xc nh khong offset, gc nghing v hng phay 2. Xc lp cc thng s th thc - hiu chnh cc ng chu tuyn nu cn thit 155- nh ngha cc ng cong kim tra u v cui 3. Khng nh vic thc hin lnh RULED_MXTo ra mt chui lin tip cc b mt k, mi b mt c xc nh bng 2 ngcongvtorachuynngcadaoctgiacngchngdctheocc ng cong tham s ca b mt vi vic s dng cc my 3, 4 v 5 trc Mt b mt k c nh ngha bng vic ni cc im cui ca cc ng cong ca 2 chu tuyn (kn hoc h) bng cc phn on thng Khng nht thit phi xy dng b mt trc khi gia cng Vng gia cng c th c bao bi cc b mt chi tit Cc bc thc hin: 1. nh ngha chu tuyn 2. n nh cc tham s hnh thc nh ngha li cc chu tuyn hoc pha c phay 3. Thc hin lnh SRFPKT To ra chuyn ng 3 trc khot vt liu t mt vng khp kn trong khi vn dch theo bin dng cab mt chi tit. Vng khp kn c nh ngha bi cc ng chu tuyn bao quanh B mt chi tit khng b xn thnh mt cnh chungCcbmtkimtracthcxcnhnhnghaccvngct.C th kim tra s va p ca dao vo cc b mt chi tit cng nh cc b mt kim tra. S va p c ngn nga gia cc b mt v tt nhin trong mt b mt khi bn knh cong nh hn bn knh dao ct Nhiu k thut ct c th c p dng SPIRAL CUT, t trong ra ngoi hoc ngc li PARALLEL CUT khot zigzag dc theo ng thng di mt gc xc nh,bcdaongangcth c xc nh bng SCALLOP hoc bng gi tr xc nh 156 RADIAL CUT dc theo cc dng thng vi gc nghing tng dn Cc bc thc hin 1.nhnghaccbmtphnghoccongcachititvnucn thit cc b mt kim tra 2.nhnghangchutuynkhpknvnucnthitnhngha cc o, khong offset, hng offset cho mi chu tuyn 3. n nh cc tham s hnh thc nu cn thit 4. thc hin lnh SRFPRF To ra chuyn ng dao 3 trc ct dc theo mt cnh ca ng chu tuyn kn hoc h trong khi vn i theo cc b mt ca chi tit Cc b mt chi tit khng b xn thnh mt cnh chung. Cc b mt kim tra c th c nh ngha xc nh vng gia cng Cthkimtrasvapcadaovoccbmtchititcngnhccb mtkimtra.Sva p c ngn nga gia cc b mt v tt nhin trong mt b mt khi bn knh cong nh hn bn knh dao ct Nhiu k thut c th p dng y Phay mt chiu v hai chiu CLIMB, CONVENTIONAL v phay hn hp Tinlidaotheophngtiptuyn,phptuyn,vngphn gic Ti mi lp ct ng ct nhiu pha c th c thc hin i vi ch ct th Vickimtratonbsngnngavicct phm vo ng chu tuyn Vic xn cc vng c gy ra bi cc bn knh ca cung cong do n qu nh Xc nh tc ct khc nhau cho vic phay gc Cc ng cong kim tra c th thm vo hoc xo i nu cn thit Cckhongoffsetiviccbmtchitit,bmtkimtrav cc ng chu tuyn c th c nh ngha v hiu chnh157Cc bc thc hin 1. nh ngha cc b mt chi tit. 2. nh ngha cc ng chu tuyn kn hoc h hoc mt phng 3. n nh cc gi tr offset v hng phay 4. Xc nh cc tham s hnh thc nu cn thit: nh ngha b mt kim tra hiu chnh cc chu tuyn kimtravicnhnghaccngconghocccimkimtra u v cui nh ngha li loi chi tit, b mt chi tit v b mt kim tra 5. thc hin lnh SURCRL To ra chuyn ng dao ct 3 trc trn cc b mt ca chi tit dc theo cc ngthngc nh ngha bi hai chu tuyn. Cc ng chu tuyn cng bao vng phay Ccbmtchititkhngbxnthnhmtcnhchung.Ccbmtkim tra c th c nh ngha xc nh vng gia cng C th kim tra s va p ca dao vo cc b mt chi tit cng nh cc b mtkimtra.Sva p c ngn nga gia cc b mt v tt nhin trong mt b mt khi bn knh cong nh hn bn knh dao ct Nhiu k thut gia cng c th p dng y Dc theo hoc vung gc vi chu tuyn Ct mt hoc hai chiu Nhiu phng thc tin, li dao c th c s dng Cc bc thc hin 1. nh ngha cc b mt 2. nh ngha cc ng chu tuyn 3. nh ngha cc b mt kim tra nu cn thit 4.nnhccthamshnhthcnucnthitnhnghaliccb mtchitit,hngctgcbtuccbmtvchutuynkim tra 1585. Thc hin lnh SURMILL To ra chuyn ng 3, 4, 5 trc ca dao phay cc di k tip ca cc b mttrongkhivnbmstccngcongthamscaccbmtny.Cth chn mt cong thng thng cng nh mt b xn. Chui cc mt cong trong di chinthmtcchr rng v c th hiu chnh bng tay. Chuyn ng ca dao dc theo cc khong h v phn giao nhau ca cc b mt c ko di hoc xn bt nu cn thit v chuyn ng trn tru gia cc b mt c hnh thnh Cc b mt kim tra c th c nh ngha xc nh vng phi trnh gia cng. C th thc hin kim tra ton s va p c th ca dao. S va p c ngn nga gia cc b mt v c bn trong mt b mt m bn knh cong ca n nhhnbnknhdao.Tuynhincthgiacngbquakimtravap (gouging) thu c kt qu nhanh hn, hoc ch kim tra tng phn gn vi b mt kim tra Nhiu k thut gia cng c th p dng: Dc theo hoc vung gc vi di phay Ct mt chiu hoc hai chiu Nhiu kiu tin v li dao c th la chn Bc chy dao ngang c th c xc nh bi mt s xc nh cc vt ct, hoctheochiucaocaphnvtliucnchabct.Ccgitroffsetcth c nh ngha cho mi ng chu tuyn Cc bc thc hin 1. nh ngha cc mt cong v nu cn thit cc b mt kim tra 2. Khng dnh pha gia cng, hng ct v gc bt u 3.thitlpccthngsththcnucnthitnhnghaliccb mtcachitit,hngphay,hngct,gcbtduvbmt kim tra 4. Thc hin lnh WCUT To ra chuyn ng ca dao ct th mt khi vt liu c xc nh bi cc b mt chi tit v vic qut cc ng chu tuyn 159Ccbmtchititkhngthbxnthnhmtcnhchung.Ccbmt kim tra c th c nh ngha xc nh vng gia cng C th kim tra s va p ca dao vo cc b mt chi tit cng nh cc b mtkimtra.Sva p c ngn nga gia cc b mt v tt nhin trong mt b mt khi bn knh cong nh hn bn knh dao ct Nguyn cng WCUT nhanh c th c thc hin trong trng hp khi cc bmtchititcxcnhchnhxcvkhngckhongh,khongchng hoc vng khng th ct Nhiu k thut gia cng c th p dng y Gia cng dc theo cc ng cong m n cch u ng bao mt khong nht nh tng ng vi tng lp ct Z To ra cc ng bao tng ng vi mi lp ct. C th xc nh kiu tin v li dao imtipcncthcxcnhbingidng,bnngoi hoc bn trong vng khp kn.imtipcnctiuhoctnhtonbihthngsaochomi vnggiacngcmtimtipcnn,chung cho tt c cc lp ct. K thut Ramping down c th c p dng. Cc khong offset c th c xc nh cho mi chu tuyn v cho cc mt cong kim tra Cc bc thc hin 1. nh ngha cc b mt v nu cn thit cc b mt kim tra 2.nhnghamtchutuynkhpknvnucnthitcco,nh ngha cc khong offset v hng offset cho mi chu tuyn Ch:KhilmvicviGOUGECHECK:OFFKhngcchncc chu tuyn bao cho vc gia cng phn lm 3.xclpccthamshnhthcnucnthitnhnghaliccb mt chi tit, b mt kim tra, cc chu tuyn v khong offset 4. khng nh vic thc hin lnh ZCUT To ra chuyn ng ca dao ct th mt th tch vt liu c nh ngha bi cc b mt chi tit v vic qut cc chu tuyn 160Ccbmtchititkhngbxnthnhmtcnhchung.Ccbmtkim tra c th c nh ngha xc nh vng gia cng C th kim tra s va p ca dao vo cc b mt chi tit cng nh cc b mtkimtra.Sva p c ngn nga gia cc b mt v tt nhin trong mt b mt khi bn knh cong nh hn bn knh dao ct Dng c ct s bt u ct mt phng ct cao nht v sau dch chuyn song song vi mt XY. N s phay mi thi im mt lp song song vi mt XY ngoi tr ni chm vo cc b mt. Ngi dng c th xc nh chuyn ng theo st hnh dng ca b mt lu li b mt c gia cng bn tinh Dngcstiptcphaybntrongchutuynchoti khi chm mt phng ct thp nht hoc cho ti khi khng cn im no m dao c th ct v khng va vo cc o hay b mt Nhiu k thut gia cng c th p dng - Dc theo cc ng thng song song mt gc no - Dc theo cc ng thng hng vo mt im xc nh - Ct theo mt hoc 2 hng - Nhiu phng php tin, li dao c th la chn imtipcncthcxcnhbingidngbntronghocbn ngoi ng chu tuyn khp kn. Cc khong offset c th c xc nh v hiu chnh cho tng b mt chi tit , b mt kim tra v cc ng chu tuyn. Cc bc thc hin 1.nhngha cc b mt chi tit v nu cn thit c cc b mt kim tra 2. nh ngha cc ng chu tuyn khp knv nu cn thit cc o ca chng, nh ngha khong offset cho mi chu tuyn 3.xclpccthamshnhthcvnucnthithiuchnhccchu tuyn, thay i pha bt u nh ngha li cc b mt chi tit v b mt kim tra4. khng nh v thc hin lnh CLEANUP 161Xcnhvngkhngcgiacngcnlisaunguyncngphaybmt vi vic s dng dao phay trc v ct nhng vng ny vi vic s dng dao hin thi Hm ny c cc tham s tng t nh hm SRFPKT. Ch c mt s im khc sau: Qu trnh gia cng c thc hin qua ba bc: 1. Xp x cc b mt cong 2. Tnh ton vng khng c gia cng bc trc 3.Giacngvngcnhnghabi2bctrnvidaocthin thi Ch : Khichyhmnyttcbabccthchinli,cnghalcc vng cha c gia cng s c tnh ton li v gia cng li. Ccngchutuynctobihmny khng lin i vi hm v c th s dng bi hm khc hoc xo i hay thay i nu cn thit. Cc bc: 1. Xc nh kch thc hnh hc HocnhnghaccbmtphngcachititHocnh ngha cc mt cong v nu cn thit c cc b mt kim tra Xc nhng chu tuyn khp kn v nu cn thit cc o bn trong n cng nh khong offset v hng offset 2.Xclpccthngsththcvnucnthitxcnhlihoc hiuchnhccngchutuyn,mtcongcachitit,ccmt kim tra 3. thc hin lnh i vi my tin : Cimatron cung cp cc lnh gia cng sau: LT_ROUGH LT_FINISH LT_DRILL LT_THRED 162 LT_GROOV LT_FINIS To ra chuyn ng ca dao tin ct tinh lng d vt liu dc theo pha trong hoc ngoi chu tuyn ca chi tit Cc vng khng th ct do dao v cc hnh dng chu tuyn c ngn nga. Cc gi tr offset khc nhau c th c a ra cho cc trc X v Z v hng ct c th c xc nh di mt gc no y. Ccchuynng tin v li dao c th c kim sot. Mt im tc thi c th c xc nh bi ngi dng kim sot vic tip cn dao Cc bc thc hin: 1. nh ngha cc chu tuyn ca chi tit 2. nh ngha hng ct 3.xclpccthamshnhthcvnucnthitnhnghalichu tuyn ct v hng ct 4. Khng nh v thc hin lnh Cc hng dn chung 1. Trc X ca MACSYS ph hp vi trc Z i vi chuyn ng tin v Y ca MACSYS s ph hp vi trc X ca chuyn ng tin 2.Chuynngktthccthchinphhpvichutuyn chn 3. Cn phi quan tm ti vng UNDERCUT m dao khng vi ti 4. LT_FINIS kim tra rng khng c mt Looping no c thc hin trnngchydaovngchutuyncachititkhngb xuyn vo 5.LT_FINISt ng nh ngha mt chu tuyn ca phi , ng chu tuyn ny c th c hin ra trn mn hnh LT_GROOV To ra chuyn ng ca dao ct rnh 163Nhiuphngphpcthsdngctrnhnhctngknhtrong, ngoi, ct mt u, ct th, ct tinh Cc bc thc hin 1. nh ngha chu tuyn rnh 2. nh ngha hng offset 3.xclpccthamshnhthcvnucnthitnhnghalichu tuyn v hng offset 4. khng nh v thc hin lnh Cc hng dn chung 1.Phicgitolmngni2gccachutuynrnh. ng thng ny ch c ct bin dng rnh 2 ln 2.Khitorarnhdaosbmchnhxccongngbindng rnh,khngvachmnoxyravkimtraydsmbo chc chn rng vt liu khng b t ct bi dao 3.ivichFINISHONLYVROUGH+FINISH:Sdng ccnisuyngtrntoratpG-CODEngnhn,nu RADIALOFFSETKhcFACINGOFFSET,phpnisuytuyn tnh s c dng LT_GROUGH Torachuynngcadaotinmnctthphndcavtliudc theophatronghocphangoingchutuyncachitit,baogmctu chn ct mt u Trnhcvngkhngcctdodngcvhnhdngcachutuyn. Cc khong offset khc nhau c th s dng cho cc trc X v Z v hng ct c th c xc nh di mt gc bt k Ccchuynng tin v li dao c th c kim sot. Mt im tc thi c th c xc nh bi ngi dng kim sot vic tip cn dao Cc bc thc hin: 1. nh ngha chu tuyn ca chi tit 2. chn pha ct 3. nh ngha chu tuyn ca phi 1644.xclpccthamshnhthcvnucnthitnhnghalicc chu tuyn cng nh hng ct 5. Khng nh v thc hin lnh Cc hng dn chung 1.TrcXcaMACSYStngngvitrcZcachuynngtin v trc Y ca MACSYS tng ng vi trc X. Cc trc ca h to my tin c hin th y mn hnh 2. Qu trnh ct th xut hin bn trong vng c xc nh gia Chu tuynphivchutuyncachitit.oy2chutuyn phi giaonhau to ra vng khp kn 3.Ccchuynngcttinhcthchintngngvi vic chn chu tuyn ca chi tit. Nu khng c mt chuyn ng ct tinh no cthchin,cnghahngcachutuynchititkhngph hp 4.Viclutmtivngkhngcctdodaokhngvitilrt quan trng 5.Hmskimtrarngkhngcmtvng(looping)no c hnh thnh trong ng chy dao v cc chu tuyn ca chi tit khng b ct lm vo LT_THRED Torachuynngcadaotindngctren.cthchnchren trong, ren ngoi v "facing". Ccvngdaokhngvitidohnhdngcadaovbmtcngn nga."Ccchngtrnhcongiacng"(Machinesubroutines)cthcs dng. Mt hoc nhiu ln xut pht c th c xc nh Cc bc: 1. Ch ra im bt u v kt thc ca ren 2.Thitlpccthngshnhthcvnucnthitnhnghali im bt u v kt thc 3. Khng nh v thc hin lnh 165Hng dn s dng chung 1. Cc chuyn ng ca dao tin c m t trong cc h to my tinmkhngphilMACSYS.Cctrccahtomytin vcaMACSYSchinraymnhnh.Khingchy dao ng li, n cng c di b 2.TrcXcaMACSYStngngvitrcZcaccchuynng mytinvTrcYcaMACSYStngngviTrcXca my tin. 4.2 Phng thc chn cc i tng hnh hcNh trnh by trn: sau khi gi bt k mt lnh gia cng no, chng ta uphitinhnhchnccitnghnhhckhcnhaunhmtcong,cc ng chu tuyn nh ngha v hn ch vng gia cng. a. Chn cc mt cong Vic chn cc mt cong c tin hnh khi xut hin li nhc: PICK SURF. & EXIT hoc PICK CHECK SRF/EXIT Mcnhtacthchnccmtcongbngcchnhychutvon. dngccphngthcchnkhc,tanhnvhthngsara mn hnh menu sau: SINGLE BOX ALL UNPICK SINGLE : l ch mc nh nh m t trn BOX:Chnccmtphngbngcch v ra mt khung ch nht v tt c cc b mt nm trong khung ny s c chn ALL: chn tt c cc b mt UNPICK: B chn cc mt ch nh Sau khi chn xong cc b mt ta phi n < EXIT > b. Xc nh cc mt phng VicxcnhccmtphngtrongccbccaqutrnhNCctin hnh khi xut hin li nhc: PICK PLANE. 166 y c 3 phng thc xc nh mt phng CURVES: Xc nh mt phng bng cch ch ra mt ng cong phng hoc hai ng thng nm trong mt mt phng UCS: Dng cc mt c s ca mt UCS ch nh PLANARFACE:Chnmtphngbngcchchra mt b mt phng ca m hnh c. Chn cc ng cong cho cc chu tuyn Vic nh ngha cc chu tuyn bao gm c chn cc ng cong c tin hnh theo cc bc sau: 1. n nh cc tham s ( nu c ) v chn ng cong u tin ca chu tuyn 2. Chp nhn mt hng dc theo ng chu tuyn xc nh trt t chn cc ng cong tip theo 3. Chn cc ng cong cn li ca chu tuyn 4. Sau khi tt c cc ng cong c chnhy n < EXIT > 5. POSTPR : S DNG B HU S L Bc cui cng ca quy trnh NC l s dng b hu s l dch cc khi dcchuyndao trong mt ng chy dao thnh dng m iu khin my CNC. Mcch chnh ca bc ny l to ra cc tp G_CODE tuy nhin ngoi nhng tpnyCIMATRONcncungcpchochngtahainhmtpdliukhcvi mc ch tr gip, hng dn cho nhng ngi iu khin my CNC sau ny: 1. Nhm cc tp bo co bao gm: Cc tp cha ng cc thng tin nhc nh ngi iu khin my, Cc tp cha danh sch v thng s cc dng c ct s dng trong tng ng chy dao c th Danh sch cc chu trnh s dng trong ng chy dao Danh sch cc gc to my cng vi cc ng chy dao 2. Nhm cc tp ngun dng cho b hu s l bn ngoi167 Cc tp ngun Cc tpbo co Cc tpG_CODE To ra v ng ng chy dao Gi lnhPOSTPR CU TRC CC TP TO RA TRONG QU TRNH NC VictoracctpG_CODEcththchintrctiptbntrong CimatronbnglnhPOSTPRhocthchinbnngoimtrngCimatron bng cch chy EXTPST.Lnh POSTPR c thc hin qua cc bc sau: TrckhithchinlnhPOSTPRchngtaphingccngchy dao v ghi n li bng lnh CLOSE_TP. Chn b hu s l tng ng vi my gia cng XcnhtoX,Y,Zkhitogcto ca my gia cng ( tt nhin khi lp trnh bng to tng i sau ny ta c th d dng thay i gi tr ca cc to ny nu mun ) Xc nh cc thng s th thc khc nhau tu theo tng b hu x l v n ENTER thc hin lnh Trong thc t sn xut ta thng gp cc my CNC do nhiu hng sn xut khcnhauvsdngcchiukhinkhcnhau.ChnhvvyCimatron cung cp cho chng ta kh nng t vit v bin dch cc b hu s l cho nhng h thng m Cimatron cha h tr trc tip c. Cng vic ny c thc hin trn mi trng bn ngoi Cimatron theo trnh t nh s sau: 168 To ra, nng cp b hu s l trong mt EDITOR: PP*.exf Dch chng trnh ngun ca b HSL DFEXF PP*.exf Vic bin dchthnh cng B hu s l bin dch PP*.dex To ra cc tp nh ngha DFSTRD P Cc li c php v cu trc EXTPST (bn ngoi )POSTPR (bn trong) Cc tp kt qu: G_CODE, REPORTS ... QUY TRNH TO RA V BIN DCH MT B HU S L Trong cc chng trnh ngun ca b hu s l chng ta cn phi quy nh cc phng thc to ra cc tp m iu khin v d nh vic lp trnh tuyt i hay tng i, phng thc to ra cc chu trnh lp, chu trnh gia cng ...6. CC CNG C TR GIP TRONG CIMATRON - NC CccngctrgipcaCimatron-NCchophpchngtaddnghiu chnhccngchydaoctoravmphngqutrnhgiacngcng nhxemtrcccktqunhnccaqutrnhgiacng.Nhcccngc tr gip ny chng ta c th trnh c cc li pht sinh trong qu trnh gia cng v a ra c mt quy trnh gia cng hp l nht. H thng cho php chng ta thay i cc ng chy dao ba cp: ng chy dao, cc th tc v cc khi dch chuyn dao. 169 cp ng chy dao: MOVE : Tt c cc tu chn ca hm MOVE c th dng di hoc COPY ton b ng chy dao mt cch trc quan bn trong mt h to my. y ta ch c thdicnhngngchydaocng.Ccngchydaoc di trong ch phng, ngoi tr tu chn DELTA. Khi mt ng chy dao c copy, ng chy dao mi s c gn mt tnmi,tnnycchiuditial8,5ktutinchratncang chy dao nguyn thu, k t tip theo l du tr v hai con s. cp th tc :Cc th tc c th c Xo, hoc thm vo v trt t gi chng ra cng c th thay i. Thm vo cc thuc tnh hnh hc cng nh cc thng s ca th tc cng c th thay i v sau th tc c th c chy li cc khi dch chuyn dao tng ng c cp nht li cc thay i cp khi dch chuyn dao: Cckhibntrongmtthtccthcxo,thmvohocthayi mt cch trc quan, iu ny to ra mt kh nng d dng kim sot dch chuyn dao tng thi im bng tay. Cc thay i ny c th b hu b nu ta chy li cc th tc : Nubnmungiramtthtcnhnghattrc,thayicc thngsvchylinhydngtuchnRERUNcaMANAG_TP. Trong trng hp ch gi ra v thay i cc thng s m khng chy li hy dng tu chn MODIFY. Cc th tc b ngt cng bc hoc b b qua s c chy li bng tu chn EXECUTE CctuchnCOPY,MOVE,DELETEdngcopy,thayitrtt vxoccthtcbntrongmtngchydaoangcm. thc hin cc tu chn ny bn ch cn chn th tc cn thao tc sau xc nhn tu chn s dng v n < EXIT >. Trongtrnghpngchydaocnhiuthtckhcnhau.d quan st ta c th tm thi du cc th tc m ta cha quan tm bng tu chn BLANK. hin li cc th tc ny ta dng tu chn UNBLANK Tuchn MANUAL EDIT dng thm tra cng nh hiu chnh bng tay cc khi dch chuyn dao ca ng chy dao c m. 170VicmphngqutrnhgiacngcthchinbnglnhSIMULATE.Qu trnh m phng c thc hin trn mt phi gia cng c nh ngha bng tu chnSTOCKCREATcaSIMULATE.ychngtacthlachnkch thc,hnhdngvmusccngnhcththchinccthaotciukhin khcnhaunh(ZOOM,ROTATE,PAN,SCALE...)trnphitora nhncmthnhnhrrngvsinhngnht.Qutrnhmphngcth cngngtmthithayi cc thng s cng nh hng nhn, ghi li cc bcnh th hin cc bc gia cng trung gian v v.. Sau khi m phng qu trnh giacng,quanstrhnchtlngbmtctoratacthtoracc mt ct khc nhau. Cc bc thc hin: To ra phi gia cng 1. nh ngha phi hoc bng tay hoc s dng cc b mt sn c 2. Nu cn thit, s dng POP - UP menu thay i hng nhn ca phi Cc thao tc m phng 1. Xc nh ng chy dao s c thc hin 2. Nu cn thit nh ngha mt mt ct v thay i cc thng s iu khin qu trnh m phng nh gi kt qu 171CHNG 4. NG DNG PHN MM CAE Moldex3D 4.1. Gii thiu chung v phn mm CAE Moldex3D PhnmmCAEMoldex3DdohngCoreTechSystem,iLoancung cp v pht trin. Phin bn mi nht ca Moldex3D l 7.0. CAEchvitttcaComputerAidedEngineeringchophpnhng ngi thit k v ch to khun rt ngn c thi gian thit k cng nh chi ph trong vic sn xut khun. Chng ta c th thy hai s di y: Hnh 4.1. S cc bc ch to khun mu c in C th thy, trn s c in, vic th khun c tin hnh sau khi ch to xong khun v qu trnh th cn phi c tin hnh trn khun tht. Hnh 4.2. S cc bc ch to khun mu c s gip ca CAE Cn s c s tr gip ca CAE trn, vic th khun c thc hin trckhichtokhunvvicthchtinhnhtrnmhnhmytnh.iu ny gip cho ngi thit k tit kim c thi gian cng nh chi ph th khun. 172Qu trnh th li trn thc t ch yu l nh gi li cc thng s k thut ca b khun. Ttnhin,cththy,ccktqutnhtonphthucrtnhiuvocc iukinuvomngisdngcungcpchomytnh.Thngthccs liu u vo u khng st vi thc t nn cc kt qu tnh ton khng tht chnh xc100%.Tuynhin,ccktqunyschochngtabitmtbctranhkh trc quan ca ton b cc qu trnh hnh thnh sn phm nha trong lng khun v gip ta trnh c nhng sai st khng ng c khi thit k khun.Moldex3D gm 5 m un chnh sau: o Moldex-PROJ:lmunqunlccdn.Tiy,chng ta c th thit lp c cc thng s cng nh cc iu kin ban u cho Moldex3Dtnhtonccmunsau.Ccthngscthgm: mhnhkhunmu(snphm)thitkbi1phnmmCAD no,vtliucasnphm,mypphunvquytrnhpphun nha,....Ngoira,munnycnchophphinthccktqu tnhtonbnghnhnh,tpvnbncngnhcconphimm phng qu trnh p phun nha trong lng khun mu. o Moldex-FLOW: phn tch dng chy ca nha lng (hay cn goi l qutrnhinycanhalng)tronglngkhun.Ktqutnh ton ca m un ny s cho ta mt hnh nh v qu trnh chy ca nha lng t c th tm ra cc sai st khi thit k khun c bit l trnh hin tng khng in y. o Moldex-PACK/COOL:phntchqutrnhngcvnhhnh snphmtronglngkhun.Sphntchnyschotathymt bc tranh ton cnh ca sn phm trc khi ly ra khi khun. Cc li nh bt kh, vt nhn hay to hnh vn do dng chy,... s c tm thy m un ny. o Moldex-WARP: tnh ton s co ngt v cho chng ta thy mt bc tranhvscongvnhcasnphmkhiclyrakhikhun mu. o Moldex-RIM/GASIN: m un ny dng tnh ton trng thi in y v s tn nhit ca cc vt liu ng gi IC. N c s dng trongvictnhtonkimnghimqutrnhphmtlpnhac chng ln cc chp x l nhm to 1 lp bo v chc chn cng nh 173lmmitrngtruynnhitkhilmvic.Hinti,VitNam cha c nh my sn xut IC nn m un ny cha dng n. Moldex3Dlskthpcanhiuccnghincuvvtliu,vvtl ca qu trnh truyn nhit, v cc phng php gii tch s v phn t hu hn. Hnh 4.3. C s ca Moldex3D Trong Moldex3D s dng 2 dng m hnh hnh hc l: -Moldex3D/Shell:l phng php phn t hu hn thc hin nhanh. -Moldex3D/solid:l phng php th tch hu hn-thc hin mc cao.4.2. Moldex3D/Shell 4.2.1. Khi nim v m hnh 4.2.1.1. L thuyt v Shell yphngphpsdngmtmhnhdngkhung(shell)lm c s sau nh ngha cc b dy ca tng phn ring bit theo nguyn tc: -Nu m hnh l mt tm phng c kch thc khng thay i th ta ly mt trung bnh lm khung c s nh ngha b dy ca tm. -Numhnhltmcnhiubdykhcnhauthtachiuxung1b mt chung v sau nh ngha b dy cho tng phn ring bit. 174 Hnh 4.4. M hnh tnh ton Shell Hnh 4.5. nh ngha b dy ca chi tit 2. Cc dng li ca Moldex3D/Shell TrongMoldex3D/Shellcungcp2loiphntlphnttrcthngv phn t tam gic thng. Thng thng cc knh lm mt, knh dn dng phn t trc thng; cc ca phn phi, ca qut s dng phn t tam gic. Hnh 4.6. Dng phn t ca Shell 3. n gin ho li tam gic thc hin vic m phng, thng thng ta s dng phng php phn thuhnchia hnh dng ca m hnh thnh nhiu phn t nh. Kt qu c bit nh l cc li. Nu s lng cc mt li khng th hnh dng c th khng ng vi thc t. Ni s lng mt li ln hn ta s c hnh dng ca m hnh gn vi thc hn, tuy nhin nu s lng li qu ln s lm cho tc tnhtongimi.Khivtmpmtminsdngnhiuphntschoktqu 175tthn,nhngcnphiloibcccnhscvphntnh.Thmvonu hnh dng l cc phn t nh phc tp trong vi trng hp ta c th th b qua chng.4. Xut cc li tam gic Mt trong cc vn quan trng khi xut cc phn t li l vic lin kt chngli.Viclinktchngcnckimtratrckhixutsangdngm hnh. Khi tha cc l hng ca li s c th gy nn cc mi ni khng hp l, rkhhocmtssckhcmkhngththotkhitrongthct.Cccch thccutrclncclilkhcbittheoviclachnbmt.Ngis dng nn hiu s lch gia hnh dng v li tip cn khun mu thc t. Do ccngtha,ghi;cch,lthahocccminikmcncloi b khi to li. 5. Cht lng ca li Chtlngcalinhhngnhiuquvchnhxckhim phng. Nu cht lng ca li qu ti kt qu phn tch m hnh li s khng cn ng vi m hnh thc t. ni chung mt trong cc phng php ci thin cht lng li l da trn gi tr ca T l tng quan , Nu gi tr nh hn 0,6, phn t c xem nh c cht lng trung bnh; 0,3 coi nh cht lng km. Trong Moldex3D/Shell th t l tng ca hu ht cc phn t s c iu khin trong khong 0,4-1 mt cch t ng. N lm cho kt qu gn vi thc t hn. Hnh 4.7. Cht lng ca b mt xp x 1766. Mt ca liTheocccptrcy,mtlicaothmhnhcthgnvi thchn.Tuynhinvimtlicaotinguyntnhtonihicaohn, gii php phi tt hn. Do vic cn bng s lng v ti nguyn s cho mt li hp l. Thnh thong trong cc min c s bin ng ln nh cc ni c cc mi ni, vng c b dy thay i v mt s c cu trc c bit mt li phi c tng ln m bo kt qu phn tch l xc thc. C xut: -Cc phn tch s b c thc hin vi t hn cc phn t mc ch l tm ra hng ca m hnh in y. -Cc phn tch tin tin c thc hin vi nhiu phn t hn mc ch l t c cc kt qu xc thc. 4.2.2. Th tc to li 1. Biu lu thng Ni chung t tc to ra li cho m hnh Shell c chia thnh 5 bc theo s sau: 2. a vo hnh dng hoc m hnh liTrongModex3D,ccTinxlsdngRhinovimunModex3D-Mesh.Thngthngc2kiufilehnhhccthcxutsangTinxl. Sau khi kt xut sang file hnh hc phi c cu trc li v ph li li ph hp vi cc phn tch ca Moldex3D/Shell. -file CAD-file Mesh 3. To liTh tc to li c th theo s khi sau: Bc 1: chn mt bn ca cc b mtSnphmgislvinthoiihitnhmthutcnghla chn b mt pha li phn nh hnh dng thc. Vi cc sn phm mng khc, cnghlachnbmtphatrnphnlhngvhuhtccctrng nm trn n. 177Bc2:nhplicccnhkhnglinktthnhcccnhchung(share) cng nhiu cng tt. Vicnicccnhkhnglinktcthchonthnhbngtaybng cc hm cung cp bi Rhino hoc hiu chnh dung sai ca m hnh sau khi nhp hnh dng.Bc 3: Quyt nh mt ca cc phn t Theocccptrcy,thlviccnbngccyut.Slng cc phn t nn c cn nhc ti hiu qu v chnh xc. Ni chung cc kch c nh nhau ca cc li l c th chp nhn. Tuy nhin trong mt s trng hp cc c im nh b c th nh hng n kt qu m phng, v n khng th b quac.Lcncnghlthmvochcnngnttinhchnhnode seedingnhrchiudicuthnhticcc im nh b m bo cht lng ca cc li. Bc 4: Gn cc min khc nhau cho m hnh hnh hc Phng php phn chia m hnh hnh hc thnh cc min khc nhau c s dng m phng cc s thay i dc theo hng ca b dy. N cn nh r cc c im khc nh l cc knh nng chy. 4. To khun mu thu c cc phn tch ton din, cn c dng nn khun mu. Nu victhitkkhunmubngCADl hp l, ngi dng c th nhp file CAD trctip.Vichiuchnhkhunmucthcthchinddnghntrong Rhino. 5. Thit lp cc thuc tnh Bc 1: nh ngha mt cavity nh ngha b dy ca min li theo min. Nu c cc min khng cng chiu dy, n c xut phn chia thnh mt nh r v ph li li. Nh mt s la chn ngi dng c th xy dng li bi chc nng 3D face bng tay vi cc b dy khng ging nhau sau li c chia thnh cc phn t nh hn. Bc 2: nh ngha mt khun c s Ngi dng cng c th la chn khun c s v chn vt liu lm khun 178Bc 3: Cc ng lnh v ng nng TrongMoldex3D-Mesh,hthngngrnhcxydngddng bngcconthng.Choccontrn,hnhdngcchnhbngcc ng knh cho im cui trc v im cui sau, vi cc on khng trn, hnh dng c ch nh bng cch s dng ng knh tng ng. Bc 4: nh ngha cc knh lm mt TrongMoldex3D-Mesh,ccknhlmmtdcxydngbngcc ng thng. nh r cc thnh phn lm ngui nh ch phun ln hoc cc vch ngn, c th c gn vo bng cch s dng cc tnh cht ph. Bc 5: nh ngha cc thit lp cho cc im c bit tonnmtmphngtondin,cnphithitlpcngvonng chy. Vi h thng lm mt, cn thit lp cng vo lm mt. Thmvonhncthngtintmthinhlccngcongs kinbaogmpsut,nhit,tlbindngCnphithitlpccntcm bintinhngnimmnhmongmun.nhgithngtinngcongs kintrongmunMoldex3D/Shell.Ntcmbinnncgntrong Moldex3D-Mesh trc khi xut m hnh sang Moldex3D/Shell. Bc 6: nh ngha cc nt o c nh gi cc tnh cht cc b, ngi dng c th thit lp cc im o c ti vng thit k. nh gi thng tin cc b bng cch s dng cc nt o ctrongmunMoldex3D/Shell.NtocnncgntrongMoldex3D-Mesh trc khi xut m hnh sang Moldex3D/Shell. Bc 7: nh ngha im iu khin ca van ikhiimiukhincavancyucuiukhinlulng dngchytcccngkhcnhau.imnyncspxptheothth thngHOTRUNNERvnhrthigianbtProcessConditionWizardca Moldex3D/Shell.Tngtimiukhincavannncgntrong Moldex3D-Mesh trc khi xut m hnh sang Moldex3D/Shell. 1794.3. Mt v d vi Moldex3D/Shell 4.3.1. Cc bc c bn khi ng dng phn mm CAE Cthnirng,huhtccphnmmCAEudatrnmhnhtnh ton ca phng php phn t hu hn nn c mt s cc bc c bn sau: Bc1:ThitkmhnhsnphmnhatrnphnmmCAD.Phn mm CAD ny l bt k tu thuc vo thi quen s dng ca ngi thit k. Bc2:Hiuchnhvxpxmhnhsnphm.CcphnmmCAE luncungcpnhng cng c hiu chnh cc m hnh ca sn phm sao cho at cmtsyucucbnnh:ccbmtphilintipnhau(khnggin on),ccb mt khng c chng cho ln nhau,.... Thng cc cng c ny cnhngktvomtsphnmmCADno,docchnglinktvi nhau to ra. Kt qu ca bc ny l vic kt xut ra tp xp x m hnh bng tamgic,agic,hnhhphaytdin,btdin,...tuthucvoyucu. Nguyn l c bn y l "chia nh m hnh thnh cc m hnh c bn nh hn dtnhton".Ttnhin,vicchianyscntichnhxcchovot ngisdngvsktdnhgiaccphntcon.Thamkhothmmc 4.2.5 trn. Bc 3: To mt d n trong phn mm CAE. Trong d n ny, chng ta lnltnhpccthngsbanunh:mhnhxpx,vtliucasn phm,quytrnhcngnghbmnhalngvolngkhun(thigianvp sutbm,thigianlmngui,ktcuvstraoinhitcahthnglm mt,...),.... chnh xc ca cc kt qu tnh ton ph thuc rt ln vo cc yu t u vo c nhp ti bc ny. Bc4:Tnhtonv hin th kt qu. Thi gian tnh ton ph thuc vo chnhxcyucu.Ccktqutnhtonthngcthhinbi hnh nh tnh, ng (phim) hay cc th. Bc5:cccktqu.Bcnyrtcncckinhnghimcacc chuyn gia v khun cng nh v nha. Vi phn mm CAE Moldex3D, phn mm CAD c s dng bc 2 lRhinocerosphinbn3.0.ivicckstngsdngAutoCADth Rhinoceroscgiaodinvccculnhkhging.Mtthanhcngcc chn vo Rhinoceros cho php ngi dng hiu chnh v kt xut ra tp xp x b mt chi tit nha. Giao din chnh ca Rhinoceros nh sau: 180 Hnh 4.8. Giao din ca Rhinoceros Thanh cng c (toolbar) nm pha bn tay phi chnh l ca Moldex3D-Mesh v n c th lm vic trc tip vi m hnh. 4.3.2. Bi tp thc hnh Giithiu:Giithiuccknngcbn ca Rhino, lm th no to ravcothinlisdngmtmhnhtrongCADto.Saumbotnh hplcali,gncctnhchtitngphntchvxutsangmhnh vi dng file liMoldex3D/Shell (*.msh), gii thiu cch to mt d n v cc d liu cn thit phn tch. Sau khi hon thnh c th m rng bng cch thm vo khun c s v cc ng lm mt, gii thiu thm lm th no thit lp cc tham s yu cu cho cc phn tch. 181 Hnh 4.9. M hnh v in thoi cn c tnh ton v kim nghim MhnhtrncthitktrnphnmmAutoCAD2000vcxut sang dng IGES. Chng ta s s dng Rhinoceros tin hnh hiu chnh li m hnh trn v kt xut ra tp xp x tam gic. 1. Chy phn mm Rhinoceros. Nhp m hnh CAD vo: Chn chc nng Import, nh n th mc /Moldex3DR700/Tutorial/CAE files/ch2/phonecover.igs 2. Thit lp lp v (layer): Chn Edit layer, tt tt c cc lp khc v ch li lp Cavity Hnh 4.10. Thit lp lp (layer) 3. Kt hp cc b mt: ChnchcnngSelectAllrichnJoin(nmtoolbarcaMoldex3D-Mesh). Cc b mt lin tip nhau s c kt ni thnh 1 b mt. Mc ch l to 182ra c 1 b mt duy nht s h tr tt hn cho vic hiu chnh v sau cng nh chovictnhton.Thngthng,nucthJoin c cc b mt li vi nhau thkhngcnccbchiuchnhnamcththchinngaybctoli tam gic. 4. To li tam gic Mesh ChnchcnngCreateSurfaceMesh(toolbarMoldex3D-Mesh),chn All. Thng s cn thit to Mesh l kch thc ca mt phn t li xp x. Hnh 4.11. nh trc kch thc li im xp x 5. Kim tra cht lng ca li tam gic va to ra ClickvoShowqualitytable (Moldex3D-Mesh toolbar), bng cht lng meshhinra.Nu gi tr Average value nm trong khong 0.8 n 1 th t yu cu. Nu khng cn phi lm li bc 4 (cho kch thc phn t nh hn na) 6. To ra cc phn t khc ca khun mu -To ra rnh dn nha: dng lnh Line to ra cc ng dn nha. Ni nha c phun vo c nh ngha bi mt Point. -ToknhlmmtcngbnglnhLine.Ccimvovracanc cng c nh ngha bi cc Point 183 Hnh 4.12. To ra ng phun v dn nha6. nh ngha cc thuc tnh ca m hnh -nh ngha chiu dy ca m hnh: Cavity (Part Face) -nh ngha rnh dn nha: Cold runner -nh ngha u phun nha (cung phun): Hot runner -nh ngha im phun vo ca nha: Melt entrance -nh ngha knh lm mt: Cooling channel -nhnghaimvovimracanclmmt:Coolantentrancev coolant exit Cc nh ngha trn c thc hin bi vic chn i tng cn t thuc tnh ri nhn vo nt Attribute setting (Moldex3D toolbar). Hnh 4.13. nh ngha b dy m hnh chi tit 184 Hnh 4.14. nh ngha knh phun nha (hot) v knh dn nha (cold channel) Hnh 4.15. Hnh nh knh phun v dn nha sau khi c nh ngha Hnh 4.16. nh ngha im phun vo ca nha 1857. Kt xut ra tp mesh ChnchcnngExportShellmodel(Moldex3D-Meshtoolbar)kt xut ra tp tam gic phc v cho vic tnh ton trn Moldex3D n y, chng ta hon thnh xong cc bc chun b m hnh tnh ton. Vic tnh ton c tun theo s khi sau: Hnh 4.17. S cc bc c bn tnh ton trong Moldex3D 8. Chy phn mm CAE Moldex3D. Thit lp 1 d n mi -nh ngha tn ca d n -nh ngha dng tnh ton: Chn Regular analysis -nh ngha phng php gia cng nha: Traditional injecton molding -nh ngha m hnh tnh ton: 3D shell solver (2.5D) 186 Hnh 4.18. Kt qu ca vic thit lp d n 9. Nhp m hnh xp x vo d n Chn chc nng Import v chn tn tp mesh va kt xut c t bc 7 trn. Kt qu c c m hnh nh sau: Hnh 4.19. M hnh tnh ton 10. Chn vt liu cho m hnh ClickvoNew/CurrentMaterialbthpthoichnvtliuca Moldex3D 187 Hnh 4.20. Chn vt liu t t vin vt liu nha ca Moldex3D 11. nh ngha cc thng s cng ngh ca qu trnh p phun nha Cc thng s c th gm: p sut phun, nhit phun, cc bc phun, thi gian phun, thi gian lm ngui trong khun,.... Hnh 4.21. Xc nh quy trnh phun nha 12. Chn b s liu thc hin vic tnh ton Ccbcchnmhnh,vtliuvccthngscngnghcthc sdngnhiulnvimcchcthchnracccktquchnhxc nht.bcny,ngikssquytnhchnmtbmhnh,vtliuv thngscngnghbtutnhton. Mi kt qu tnh ton thu c s c lp v cho php lu tr li phc v cho vic so snh v sau. 188Hnh 4.22. Chn b thng s tnh ton 13. Hin th cc kt qu Moldex3D cho php hin th nhiu kt qu khc nhau ca nhiu qu trnh tnh ton khc nhau. la chn, chng ta c th chn trong Result v Item. Hnh 4.23. Kt qu tnh ton ca Moldex3D 189CHNG 6. NG DNG MATLAB TRONG K THUT 6.1. Cc cng c ni suy ca MatLAB Trong vic x l cc vn k thut, ni - ngoi suy l mt cng c ht sc cnthitcbitkhisldliuthcnghimhoc cc d liu cho di dng bng.Vdnhhstitlucavanlmthmthcnghimphthucvo vntccadngchy,nhitvkchthchnhhccalvan.Tuynhin bngthcnghimchngtachcthxcnhccc h s ny cc gi tr xc nh ca nhit , vn tc v kch thc hnh hc. c c gi tr ca h s tit lu ti bt k gi tr no ca i s chng ta phi s dng cc hm ni suy. Phndiychngtasxtticchmni-ngoisuycaMatlabv cc v d s dng chng.6.1.1. Hm ni suy mt bin: interp1 C php:yi = interp1(x,Y,xi) yi = interp1(x,Y,xi,method) Trong : x, Y l hai vc t c cng kch thc xc nh cc im (xi, yi) vc t x phi tng dn hoc gim dn im xi cn nm trong khong t x(1) n x(n) method quy nh phng php ni suy: cc gi tr ca n l: 'linear' ch ni suy tuyn tnh (mc nh)'nearest' ch ni suy s dng gi tr nt gn nht'spline' ni suy hm spline bc 3'cubic' ch ni suy a thc bc 3V d: Ta c cc d liu dn s ca nc M cc thi im cch nhau 10 nm nh sau: t = 1900:10:1990; p = [75.99591.972105.711123.203131.669 150.697179.323203.212226.505249.633]; 190interp1(t,p,1975), s cho ta gi tr ni suy v dn s vo nm 1975 vi kt qu l:ans =214.8585 6.1.2. Hm ni suy hai bin 1. S dng hmInterp2 C phpZI = interp2(X,Y,Z,XI,YI) ZI = interp2(Z,XI,YI) ZI = interp2(X,Y,Z,XI,YI,method) Trong : o ZI = interp2(X,Y,Z,XI,YI) a ra ma trnZI cha cc phn t tng ng vi cc phn t quy nh trong ma trn XI, YIv c xc nh bi php nisuycahmhaibinxcnhbiccmatrnX,YvZ.X,Ycn phitnghocgimdnvccngkchc,ccungcpbilnh meshgrid.o ZI=interp2(Z,XI,YI)scoinhccvctX=1:nvY=1:m,y [m,n] = size(Z).o ZI = interp2(X,Y,Z,XI,YI,method) cho php s dng cc phng php ni suy khc nhau:'linear' ch ni suy tuyn tnh (mc nh)'nearest' ch ni suy s dng gi tr nt gn nht'spline' ni suy hm spline bc 3'cubic' ch ni suy a thc bc 3cthnisuynhanhhnkhiccmcnisuycchu,chngtahydng cc ch '*linear', '*cubic', '*spline', hoc '*nearest'. Ch :o XIvYIcthlccmatrn,khi interp2 s a ra cc gi tr tng ng vi cc im (XI(i,j),YI(i,j)). Ngoi ra ta cng c th a vo cc vc thngvctxivyi.Trongtrnghpny, interp2 s chuyn i cc vc t ny thnh cc ma trn ging nh ta s dng lnh meshgrid(xi,yi).o X, Y cng c th l cc vc t, khi phi ht sc lu tm ti trt t a cc vc t vo trong cu lnh. 191Vd:Tacdliuvtinlngcacngnhnccnmt1950n1999 theo thi gian phc v a ra trong bng sau: Nm/thi gian phc v10 (nm)20 (nm)30 (nm) 1950150.697199.592187.625 1960179.323195.072250.287 1970203.212279.092322.767 1980226.505353.706426.730 1990249.633320.281598.243 xcnhctinlngcacngnhnsauthigianphcvbtk (t10n30nm)vtinhngthiimkhcnhau(tnm1950n1990), chng ta phi s dng hm ni suy hai bin. Trc ht chng ta phi to ra cc vc t mc ni suy: years = 1950:10:1990; service = 10:10:30; Ma trn d liu c nhp vo ng theo nh trt t cho trong bng: wage = [150.697 199.592 187.625 179.323 195.072 250.287 203.212 279.092 322.767 226.505 353.706 426.730 249.633 320.281 598.243]; Tcsdliunytacthxcnhctinlngcacngnhn nm 1975 vi 15 nm phc v:w = interp2(service,years,wage,15,1975) Cho kt qu: w =265.6287 Ch : s dng ng lnh interp2 chng ta phi ch n trt t ca cc i s ca lnh:isthnhtlvctmcnisuynmtrnhngcabngd liu.i s th hai l vc t mc ni suy nm trn ctca bng d liu. i s th ba l ma trn d liu, 192Ccisth4,5lccgitrtngngvivctmcnisuy th nht v th hai.2. S dng hm meshgrid To ra ma trn x v y dng xc nh gi tr ca hm 2 bin, v th hai chiu v xc nh cc ma trn mc ni suy dng cho lnh interp2.C php [X,Y] = meshgrid(x,y) [X,Y] = meshgrid(x) [X,Y,Z] = meshgrid(x,y,z) Trong :[X,Y] = meshgrid(x,y) Chuyn cc vc t x v y thnh cc ma trn X v Ydngtnhgitrca hm 2 bin v th li ba chiu. Cc hng ca ma trn X l copy ca vc t x v cc ct ca ma trn Y l copy ca vc t y.[X,Y] = meshgrid(x) c ngha ging nh[X,Y] = meshgrid(x,x).[X,Y,Z] = meshgrid(x,y,z) To ra cc mng 3 chiu dng xc nh gi tr hm 3 bin hoc v th khi 3 chiu.Ch : Hmmeshgridtngtnhhmndgridngoitrtrtthaithams u vo v ra ca hai hm c i ln cho nhau, c ngha lcu lnhmeshgrid ch dng trong khng gian hai hoc 3 chiu.V d: [X,Y] = meshgrid(1:3,10:14) S cho kt qu l hai ma trn: X = 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 Y = 193101010 111111 121212 131313 141414 6.1.3. Php ni suy 3 bin v n bin 1. S dng hm interpnC php VI = interpn(X1,X2,X3,...,V,Y1,Y2,Y3,...) VI = interpn(V,Y1,Y2,Y3,...) VI = interpn(V,ntimes) VI = interpn(...,method) Trong : VI=interpn(X1,X2,X3,...,V,Y1,Y2,Y3,...)NisuytmccgitrVI ca hmnhiubinVticcimarabngccvctY1,Y2,Y3...nh ngha V ta cn dng cc mng X1, X2, .. Xn. xc nh cc im m ti d liu ca hm c a ra. VI=interpn(V,Y1,Y2,Y3,...)thchinphpnisuynhtrnvcoiX1= 1:size(V,1), X2 = 1:size(V,2), X3 = 1:size(V,3), ... VI = interpn(...,method) cho php xc nh phng php ni suy.'linear' ch ni suy tuyn tnh (mc nh)'nearest' ch ni suy s dng gi tr nt gn nht'spline' ni suy hm spline bc 3'cubic' ch ni suy a thc bc 3Ch :Y1,Y2,Y3,...Cthlccmatrn,trong trng hp ny hm interpn saraccgitrVIvitngngviccim(Y1(i,j) ,Y2(i,j),Y3(i,j),...).TacththayccmngY1,Y2, Y3... bng cc vc ty1,y2,y3...Trongtrnghpnyinterpnsthngdchccvct thnh cc ma trn ging nh dng hm ndgrid(y1,y2,y3,...).2. S dng hm ndgrid 194Toramngnchiudngxcnhgitrcahmnhiubinvni suy.C php [X1,X2,X3,...] = ndgrid(x1,x2,x3,...) [X1,X2,...] = ndgrid(x) Trong : [X1,X2,X3,...] = ndgrid(x1,x2,x3,...) Chuyn cc vc t x1, x2, x3... thnh cc mng X1, X2, X3 ... dng xc nh gi tr ca hm nhiu binhoc ni suy hm nhiu bin. Chiu th i ca mng Xi l copy ca cc phn t vc t xi. [X1,X2,..] = ndgrid(x) c cng kt qu nh [X1,X2,...] = ndgrid(x,x,...).V d: S dng hm ngrid v th li hm : 2 2y xe x Z= . .[X1,X2] = ndgrid(-2:.2:2, -2:.2:2);Z = X1 .* exp(-X1.^2 - X2.^2); Lnh mesh(Z) s cho kt qu: Ch : Hm ndgrid c dng gn ging nh hm meshgrid ngoi tr hai i s u ca cc bin vo, ra c tro i cho nhau.C ngha lcu lnh:195[X1,X2,X3] = ndgrid(x1,x2,x3) S cho kt qu cng ging nh cu lnh:[X2,X1,X3] = meshgrid(x2,x1,x3). 3. Ni suy bng hm polyfitC php:p = polyfit(x,y,n) [p,s] = polyfit(x,y,n) M t:Hm p = polyfit(x,y,n) tm ra cc h s ca a thc p(x) bc n ph hp vi d liu x, y trong ngha ca lch qun bnh bnh phng b nht. kt qulvctpcchiudin+1chacchscaathctheotrtt gim dn ca s m:[p,s] = polyfit(x,y,n) a ra a thc h s p, s dng c lng sai s. 4. Ni, ngoi suy bng hm spline C php yy = spline(x,y,xx) pp = spline(x,y) M t Hmspline To ra hm spline nhn cc gi tr y(:,j) ti im x(j) vi mi jyy=spline(x,y,xx)araccgitrcahmticcimchrabng vc t xx.pp = spline(x,y) a ra dng pp ca hm ni suy bc 3, m c th s dng vi lnh ppval. Th d Hai vc t t = 1900:10:1990; p = [ 75.99591.972105.711123.203131.669 ... 150.697 179.323203.212226.505249.633 ]; Th hin d liu v dn s ca m (tnh bng n v triu ngi). Biuthc:spline(t,p,2000)ssnghmsplinebc3ngoisuyvd on dn s nm 2000.196Kt qu s l:ans = 270.6060 6.2. Ti u cc hm s 6.2.1. Tm nghim ca hm s 1. S dng hm fzero C phpz = fzero('fun',x,tol) Trong : o 'fun' : l mt chui ch ra tn ca tp dng nh ngha hm so x c th l mt gi tr hoc l vc t c hai phn t: Nu x l mt gi tr v hng,fzerostmranghimcahmgnvigitr.Nu x l mt vc t,fzerostmraimkhngnmtrongkhonggitrgiahai phn t o tol : quy nh sai s tng i ca nghim tm ra. Nu khng quy nh gi tr tol, my s nhn gi tr sai s tng i mc nh Ch :Hmfzeroxcnhimmtithhmscnkhostcttrchonh, khng phi l khi th tip xc vi trc honh b. Th dTm nghim ca phng trnh X3-2X-5=0 gn im x=2. Bc 1:vitM.file nh ngha hm v tri: function y = f(x) y = x.^3-2*x-5; Bc 2: gi lnh fzero caMatlab: z = fzero('f',2) Kt qu nhn c z = 2.0946 1972. Tm nghim ca h phng trnh phi tuyn xcnh nghim ca h phng trnh phi tuyn trc ht chng ta phi vit mt m-fle m t v tri ca h phng trnh (trc phi chuyn v v phi ca h bng 0) sau dng lnh fsolve ca matlab. a. Vit tp m t v phi Tp m t v phi c vit di dng hm c cu trc sau: function f=(x) f= Trong : f:lbinracahm.lmtvctctcsphntbngs phng trnh trong hx:lmtvctbinclp,ccphntcanlccncntm ca h b. S dng lnh fsolve Lnh fsolve ca Matlab dng gii h phng trnh phi tuyn da trn c s phng php qun bnh bnh phng phi tuyn b nht. Thng thng chng ta s dng lnh fsolve theo c php sau: [x, fval] = fsolve('fun',x0) Trong : 'fun'ltncam-filedngnhnghavphicahphng trnh X0 l im c lng ban u ca nghim. y l vc t ct c cc phn t tng ng l c lng ban u ca cc n cn tm. Lnh s a ra kt qu lNghim: a vo vc t x Gi tr v phi ca cc phng trnh : a vo vc t fval c. Cc tu chn xut kt qu khc ca lnh fsolve Ngoi vic a ra vc t xc nh nghim v xc nh gi tr v phi ca h, lnh fsolve cn c kh nng cung cp nhiu thng tin khc m t qu trnh 198xlcalnh.lyraccthngtinnychngtaphigilnhvic php sau: [x,fval,exitflag,output] = fsolve('fun',x0) Trong : Exitflag:araccgitrmtiukinthot:GitrcaExitflag>0 chrahmtittinghimx.GitrcaExitflag=0chrasbclp tiatc.GitrcaExitflag < 0 ch ra rng hm khng hi t ti nghim tm c. Output: l bincu trc c cc trng cha thng tin v qu trnh ti u: output.iterations : S bc lp cn thc thi .output.funcCount : Sln tnh gi tr ca hm.output.algorithm : Thut ton s dng.output.cgiteration:SbclpPCG(Chsdngivithut ton large-scale).output.stepsize:lncabccuicngcsdng(Ch dng i vi thut ton medium-scale ).d. Cc tu chn iu khin ch tnh ton Cctuchniukhinchtnhtoncxclpthngqualnh optimset ca Matlab v c a vo lnh fsole thng qua c php sau: [x, fval] = fsolve(fun,x0,options) Thng s options ca lnh c xc nh bng lnh optimset sau y: options = optimset('Param1',Value1,'Param2',Value2,...)Trong : Param1, Param2... l chui tn ca cc thng s c quy nh trc trong Matlab. Value1, Value2... l cc gi tr cn xc lp ca thng s tng ng Cc thng s ca lnh optimset DerivativeCheck:Bt-ttchsosnhccgitrohm ca hm s. Gi tr ca n l 'on' hoc 'off' Diagnostics: iu khin vic in ra cc thng tin d bo v hm c ti u, hoc h ang c gii. Gi tr ca n l 'on' hoc 'off' 199DiffMaxChange:Mcthayigitrlnnhtcaccbintronghngtm kim. Gi tr ca n l s nguyn dng, mc nh l 0.1DiffMinChange:Mcthayigitrbnhtcaccbintronghngtm kim. Gi tr ca n l s nguyn dng, mc nh l 10-8

Display:Mchinthccktqutrunggian.Gitrcanbaogm:'off'- khnghinth,'iter'-Hinththngtintngbclp,'final'-chmc nh: chhin cc thng tin bc cui cng. GoalsExactAchieve:Quynhslngccimchcntcmtcch chnh xc. Gi tr ca n l s nguyn dng, mc nh bng 0. GradConstr:Bt,ttchquynhdciviccrngbucphituyn bi ngi dng. Gi tr ca n l 'on' hoc 'off' (mc nh). GradObj: Bt, tt ch quy nh dc i vi hm mc tiu bi ngi dng. Gi tr ca n l 'on' hoc 'off' (mc nh). LargeScale: Bt ch s dng thut ton 'large-scale' nu c th. Gi ca n l 'on' (mc nh ) v 'off'. LevenbergMarquardt:Btchsdngthutton'Levenberg-Marquardt' thay cho thut ton 'Gauss-Newton'. Gi tr ca n l 'on' hoc 'off'. LineSearchType: iu khin vic la chn thut ton tm kim. Gi tr ca n l 'cubicpoly' hoc 'quadcubic' (mc nh). MaxFunEvals: Gi tr ln nht cho php ca s ln tnh ton hm s. Gi tr ca n l mt s nguyn dng. MaxIter: S ln lp ti a cho php. Gi tr ca n l mt s nguyn dng. MaxPCGIter: S bc lp PCG ti a cho php. Gi tr ca n l mt s nguyn dng. GradObj: Bt, tt ch nh ngha trc dc ca hm mc tiu. Gi tr ca thng s ny l 'on' v 'off' (mc nh). Hessian:Bt,ttchnhnghatrcohmringbchaicahmmc tiu. Gi tr ca thng s ny l 'on' v 'off' (mc nh). GradConstr:Bt,ttchnhnghatrcdccahngbuc.Gitr ca thng s ny l 'on' v 'off' (mc nh). TolCon:Saischophpivicciukinrngbuc.Gitrcanls nguyn dng. TolFun:Saischophpcahmmctiu(ivibitontiu)vivi cc hm v tri ca h. Gi tr ca n l s nguyn dng. 200TolPCG:SaischophpdngbclpPCG.Gitrcanlsnguyn dng. Mc nh l 0.1.TolX:Quynhsaichophpcaccbintrngthi.Gitrcanlmts nguyn dng. e. Cc v d V d 1: Tm im 0 ca h hai phng trnh 2 n Chuyn h v dng chun: im c lng ban u l :x0 = [-5 -5]. Bc 1: TrchtchngtaphivithmM-filetnhtonraF(gitrcacc phng trnh ti x) :function F = myfun(x) F = [2*x(1) - x(2) - exp(-x(1));-x(1) + 2*x(2) - exp(-x(2))]; Bc 2: Gi ra lnh fsolve gii h: x0 = [-5; -5]; % c lng nghim ban u options=optimset('Display','iter'); % Tu chn hin th ra mn hnh [x,fval] = fsolve('myfun',x0,options)% Gi cng c ti u Sau 28 bc lp my s tm ra nghim: 201Bc lp Hm m f(x) Chunca bc Tuchnbc nht Cc bc lp CG 1 4 47071.2 1 2.29e+004 02 7 6527.47 1.45207 3.09e+003 13 10 918.372 1.49186 418 14 13 127.74 1.55326 57.3 15 16 14.9153 1.57591 8.26 16 19 0.779051 1.27662 1.14 17 22 0.00372453 0.484658 0.0683 18 25 9.21617e-008 0.0385552 0.000336 19 28 5.66133e-017 0.000193707 8.34e-009 1V d 2: Tm ma trn X tho mn h phng trnh im c lng ban u:x= [1,1; 1,1]. Bc 1: Vit M-file m t h phng trnh: function F = myfun(x) F = x*x*x-[1,2;3,4]; Bc 2: Gi lnh fsolve:x0 = ones(2,2);% c lng ban u ca nghim options = optimset('Display','off'); % Tt ch hin th qu trnh tnh [x,Fval,exitflag] = fsolve('myfun',x0,options)202Nghim ca phng trnh l:x = -0.12910.8602 1.29031.1612Fval = 1.0e-03 * 0.1541 -0.1163 0.0109 -0.0243 exitflag = 1 Ch : Nuhphngtrnhltuyn tnh, ton t \s cho kt qu chnh xc hn v nhanh hn lnh fsolve. V d gii h sau: Chng ta s thc hin cc cu lnh ca Matlab sau y: A = [ 3 11 -2; 1 1 -2; 1 -1 1]; b = [ 7; 4; 19]; x = A\b Kt qu s nhn c nghim: x = 13.2188 -2.3438 3.4375 3. Tm cc tiu khng rng buc ca hm nhiu bin tm gi tr cc tiu khng rng buc ca hm nhiu bin trc ht chng taphivitmtM-filenhngha hm s. Hm ny c i s l mt vc tc ccphntlccbinclpcahm.Sauchngtasdnghm fminsearchcaMatlabtmragitrcctiucahmlncnimc lng ban u. 203fminsearchsdngthuttontmkimn hnh. l phng php tm kimtrctipkhngsdngphngphpxcnhdcbngphngphp gii tch hay phng php s.Nu n l chiu di ca vc t bin c lp x, thut n hnh trong khng gian n chiu c c trng bi n+1 vc t khc bit nm trn nh ca chng. Trong khng gian 2 chiu, l mt tam gic, trong khng gian3chiultdin...Timibctmkim,mtimminmtrong n hnh hoc gn n s c to ra. Gi tr ca hm ti im mi c so snh vigitrca hm ti cc nh ca n hnh. Thng thng mt trong cc nh ca n hnh c thay th bng im mi v hnh thnh nn n hnh mi. Qu trnh ny s lp li cho ti khi bn knh ca n hnh nh hn gi tr cho php. a. S dng lnh fminsearch fminsearch c c php c s nh sau: x = fminsearch('fun',x0) Trong : o fun l chui xc nh tn ca M-file nh ngha hm cn ti u o X0 l vc t cc gi tr c lng ban u ca cc bin c lp Ch : 1.Tngtnhlnhfsolve,cthmccthngtinvqutrnhtnh ton ta c th dng c php:[x,fval,exitflag,output] = fminsearch ('fun',x0) Trong :fval,exitflag,output c ngha ging nh lnh fsolve. 2. iu khin qu trnh tnh ton ca lnh chng ta s dng c php : x = fminsearch('fun',x0, options) Trong:optionscxclpbnglnhoptimset(xemphntrn) viccthuctnhcsdngyl:Display,MaxFunEvals,MaxIter,TolFun,TolX b. Cc v d V d 1: Xc nh cc tiu ca hm mt bin:f(x) = sin(x) + 3.Bc 1: Vit M-file m t hm s: function f = myfun(x) f = sin(x) + 3; Bc 2: Gi hm fminsearch:204x = fminsearch('myfun',2) V d 2: Xc nh cc tr ca hm s Rosenbrock: Bnggiitchtacthxcnhchmcgitrcctiubngkhng ti im(1,1). Bc 1: nh ngha M-file c tn l banana.ms dng nh ngha hm cn ti ufunction f = banana(x) f = 100*(x(2)-x(1)^2)^2+(1-x(1))^2; Bc 2: gi hm fminsearch: [x,out] = fminsearch ('banana',[-1.2, 1.2 ]); S cho kt qu l:x=1.00001.0000 out =5.4009e-010 4. Tm cc tiu ca hm mt bin trong vng xc nh Bi ton xc nh cc tiu ca hm mt bin trong vng xc nh c vit dng ton hc nh sau: 2 1xx x x : ) x ( f Min < < Trong:x,x1,x2l cc gi tr v hng, f l hm cho kt qu l gi tr v hng. a. S dng hm fminbndHm fminbnd c dng xc nh cc tiu ca hm mt bin trong mt khongxcnh.fminbnds dng thut ton "tm kim mt ct vng" vphp ni suy bc hai. Cc c php ca lnh fminbndbao gm: x = fminbnd('fun',x1,x2) x = fminbnd('fun',x1,x2,options) x = fminbnd('fun',x1,x2,options,P1,P2,...) [x,fval] = fminbnd(...) [x,fval,exitflag] = fminbnd(...) [x,fval,exitflag,output] = fminbnd(...) Trong : 205'fun',fval,exitflag,output,options:cnghagingnhlnh fminsearch x1, x2 : l gi tr cn di v trn ca bin tm kim b. Vd Xc nh cc tiu ca hm f= X3-2X-5 trongkhong [ 0 2]. Bc1:vitM.file nh ngha hm f: function y = f(x) y = x.^3-2*x-5; Bc2:Gi hm fminbnd [x,out] = fminbnd('f', 0, 2) Kt qu nhn c l: x =0.8165, out=-6.0887 5. Tm cc tr c iu kin ca hm nhiu bin Bi ton tm cc tr c iu kin ca hm nhiu bin trong trng hp tng qut c xc nh nh sau: Trong : x, b, beq, lb, v ub l cc vc t, A v Aeq l cc ma trn, c(x) v ceq(x) l cc hm nhiu bin a ra kt qu l cc vc t, f(x) l hm nhiu bin a ra kt qu l gi tr v hng, f(x), c(x), v ceq(x) c th l cc hm phi tuyn. Matlab a ra hm fmincon gii quyt bi ton tm cc tr c rng buc cahmnhiubin.Tutheoyucuvcciukinrngbuc,chngtas dng cc c php khc nhau ca lnh fmincon. a. Cc c php ca lnh fmincon x = fmincon(fun,x0,A,b) x = fmincon(fun,x0,A,b,Aeq,beq) 206x = fmincon(fun,x0,A,b,Aeq,beq,lb,ub) x = fmincon(fun,x0,A,b,Aeq,beq,lb,ub,nonlcon) x = fmincon(fun,x0,A,b,Aeq,beq,lb,ub,nonlcon,options) [x,fval] = fmincon(...) [x,fval,exitflag] = fmincon(...) [x,fval,exitflag,output] = fmincon(...) [x,fval,exitflag,output,lambda] = fmincon(...) [x,fval,exitflag,output,lambda,grad] = fmincon(...) [x,fval,exitflag,output,lambda,grad,hessian] = fmincon(...) Trong : x = fmincon(fun,x0,A,b) : Xut pht t im tm kim ban u x0v tm ra im cc tiu ca hms m t trong M-file'fun' vi rng buc biu din bng h bt phng trnh:A*x 0, h2 >0, lk>0 vi k=2n Cc iu kin ny c th c vit di dng chung: =0 ) x ( Ceq0 ) x ( C, vi xl vc t bin thit k Bc 3: Vit cc M-file m t hm mc tiu v hm rng buc M-file m t hm mc tiu: function y=nhip(x) n=13; h=x(3)*ones(1,n);h(1)=x(2); h(2)=x(2); b=x(1); l=x(4:end); y=sum(b*h.*l)*0.0087; M-file m t hm rng buc: function [y,yy]=rangbuoc(x) nn=13; h=x(3)*ones(1,nn);h(1)=x(2); h(2)=x(2); b=x(1);al=0.85;E=2000000; l=x(4:end); l(nn+1)=0; %% Tnh ton cc c tnh hnh hc ca l nhp Jk=b*h.^3/12;Jk=cumsum(Jk); Yk=1./Jk;Yk(nn+1)=0;DYk=-diff(Yk); a=l(1)*ones(1,nn+1)-l;a=a(2:nn+1); %% Tnh cng ca nhp Ck=al*6*E/sum(a.^3.*DYk)yy(1)=Ck-85; %% rng buc v cng %% Tnh ng sut ln nht cc l nhp Q=1110*1.8;l=l(1:end-1); Jk=b*h.^3/12; Ak=0.5*Jk(2:end)./Jk(1:end-1).*(3*l(1:end-1)./l(2:end)-1); Bk=-(1+Jk(2:end)./Jk(1:end-1)); Ck=0.5*(l(3:end)./l(2:end-1)).^3.*(3*l(2:end-1)./l(3:end)-1); z=size(l);z=z(2)-1; V=zeros(z,1); V(1)=-Q/2*Ak(1); M=diag(Ak(2:end),-1)+diag(Bk)+diag(Ck,1); X=inv(M)*V; P=[Q/2 X'];lbc=l(1:end-1);lbd=l(2:end);214gt1=P(1:end-1).*(lbc-lbd); gt2=P(1:end-1).*lbc-P(2:end).*lbd; gt=[gt1;gt2];gtm=max(gt); %%ng sut ln nht gtm=[gtm P(end)*l(end)]; us=gtm./Jk.*h/2 y(1:z+1)=us-9500; %%rng buc v ng sut y=[y -x+0.004]; %%thm cc rngbuc v chiu di dng yy(2)=58.3-x(4); %%rngbuc v chiu di l th nht yy(3)=6.5-x(1); %%rngbuc v chiu rng cc l yyk=l(2:end)-l(1:end-1); %%rngbuc l sau ngn hn l trc y=[y yyk]; %%rngbuc dng bt phng trnh Bc 4: gi lnh fmincon t Matlab x0=[6.5, 0.7, 0.7, 58.3, 46.58, 41.87, 37.16, 32.45, 27.74, ... 23.03, 18.32, 13.61, 10.25, 8.9,4.2][x, fval] = fmincon('nhip',x0,[ ], [ ], [ ], [ ], [ ],[ ],'rangbuoc') Chng ta xc nh c cc gi tr ti u: Ch s lB dy l (cm)1/2Chiu di l nhp (Cm) 11.091158.30 21.091137.39 30.753017.94 40.75308.68 50.75302.79 Di y l mt s ch tiu nh gi cht lng hai b nhp dc tc dng ca ti trng 1110 Kg (ti trng ln mt nhp): TTCh tiu so snhNhp sau khi ti u Nhp c 1Khi lng (1/2 nhp khng k phn ngm) 7.157 (Kg)15.456 (Kg) 2 cng84.53Kg/cm87.62 Kg/cm 3ng sut ln nht9140 Kg/cm210605 Kg/cm2 215So snh cc ch tiu nh gi ta nhn thy nhp sau khi c ti u ho c cccctnhvttrihnhnnhptnhsbnh:Khilnggimi 50%, cng gim 4% (m bo tt hn tnh m du chuyn ng) v ng sut trong cc l nhp ti u gim 14%. iu ny khng nh c hiu qu r rt ca phng php ti u a ra. 6.3. Gii cc h phng trnh vi phn thng 6.3.1. Gii thiu v h phng trnh vi phn thnga. Dng chun ca h phng trnh vi phn Phn ln cc h ng lc u c m t trong dng ton hc chun c tn gi l dng Cauchy, l h n cc phng trnh vi phn bc nht sau: = = ) w , t ( f ) t ( W.. ..........) w , t ( f ) t ( W) n ( ) n () ( ) ( 1 1 (2-1) Trong : t l bin c lp (thng l thi gian),w(i)(t)lthnhphnthicavct W(t) c n phn tv o hm ca n theo bin t c k hiu bng w'(t).f(i)(t) l thnh phn th i ca vc t n hm ph thuc vo t, w:F(t,w) Trong dng vc t chng ta c th vit :W'(t)=F(t,w)(2-2) Cc lnh gii phng trnh vi phn trong Matlab u s dng dng chun ny,chnhvvychngtaphichuyncchphngtrnhviphnvdng Cauchy trc khi p dng cc lnh gii phng trnh vi phn ca Matlab. b. Dng h phng trnh vi phn c ma trn khi lng Trong thc t tnh ton, khng phi lc no chng ta cng c th d dng chuynhphngtrnhviphnmththngvdngtngminhnhtrn. Chnhv vy t phin bn 5.0, Matlab cho php chng ta gii cc h phng trnh vi phn dng n (c ma trn khi lng) nh sau: M.W'(t)=F(t,w)(2-3) Trong : 216 M l ma trn vung n,n : cc phn t ca ma trn ny c th l hng s, c th l hm ph thuc vo t : M(t) hoc ph thuc vo thi gian v bin trng thi M(t,w). c. Cc phng trnh cng (stiff equation) Cc h phng trnh vi phn c cc gi tr ring khc bit rt ln c gi lnhnghphngtrnhcng.Khcvicchphngtrnhviphnthng thng,hphngtrnhviphncngyucuskhcbitrtlncagitrbcthigiankhisdngphngphpsgiichng.Chnhv vy mt s phngphpsdnggii h phng trnh vi phn thng thng t ra khng hiu qu khi dng gii cc h phng trnh vi phn cng. V d v h phng trnh vi phn cng Chng ta cn xc nh nghim theo thi gian ca h phng trnh: = = = + = 0 ) 0 ( 1999 9991 ) 0 ( 1998 9982 2 1 21 2 1 1X X X XX X X X Trong dng khng gian trng thi, phng trnh c vit: x'= A.x +B.u Trong : 1999 9991998 998 = A, 00= BCc gi tr ring ca ma trn A l 1=-1, 2=-1000 Nghim chnh xc ca phng trnh c dng: t tt te C e C Xe C e C X10004 3 210002 1 1 + =+ = Chngtanhnthyrnghthngc2thnhphnchngsthigian khcbitrtln.Bcthigiancnthitkhitchphnsphngtrnhc iukhinbithnhphnhngsthigiancgitrlnhn,mbo chnhxcchngtaphichnbcthigianrtnh:vdnhnuchngta chn ln ca bc tnh bng 1/10 gi tr ngch o ca 2 th gi tr bc thi gian phi l t=0.00001 s. Tuy nhin nh hng ca thnh phn th 2 ny gim rtnhanhkhithigiantngln.Nhvykhithigianlnchngtacth tng gi tr bc thi gian ln nhiu ln y nhanh tc tnh ton. 2176.3.2. Phng php gii h phng trnh Cauchy trong MATLAB giihphngtrnhviphntrongMatlabchngtaphithchin3 bc sau y: a. Chuyn i h phng trnh vi phn v dng chun. DngchunychiutheongharngldngCauchy(2-2)hoc dng m rng c ma trn khi lng M, M(t) hay M(t,w).Khichuynivdngchuntrchtchngtaphiibinchuyn cc o hm bc cao thnh cc o hm bc nht, sau chng tachuyn h v dng vc t (dng 2-2) v chuyn iu kin u v cng v dng vc t Ch : chng ta phi ch n trt t t cc bin trong vc t bin trng thikhngnhmln chng khi gn cc iu kin u cng nh khi x l kt qu. V d: c h phng trnh vi phn m t chuyn ng ca c h sau: ) t 10 ( Sin . e Y Y . e . 2 Y ). t cos 1 (t 30 t . 15 2= + + +(2-4) Vi cc iu kin u l: Y(0)=0; Y'(0)=1; Y"(0)=2 chuyn v dng chun, chng ta i cc bin: Y=Y1; Y'=Y2; Y"=Y3 (2-5) Khi chng ta s c: Y'1=Y2; Y'2=Y3; (2-6) Th cc phng trnh 2-6 vo phng trnh 2-4 v chuyn v s c: t cos 1Y . e 2 Y ) t 10 ( Sin . eY23t 151t 303+ = (2-7) Kt hp cc phng trnh 2-6 v 2-7, chng ta nhn c h dng chun: + = = = t cos 1Y . e 2 Y ) t 10 sin( . eYY YY Y23t 151t 3033 22 1(2-8) Vc t iu kin u tng ng s l [0, 1, 2]T

b. Vit M-file m t h phng trnh vi phn (ODE File) ODEFilelmttpdngmcodedongidngvitnhnghacc phngtrnhviphndngchocclnhgiiphngtrnhviphncaMatlab 218(lnhODE)tngng.M-filenyscthamchiuntrongccculnh ODE vi tn 'ODE File' tuy nhin chng ta c th t cho n cc tn bt k. McnhcclnhODEsgiiccbitonviiukinudng: dy/dt=F(t,y),ytlmtbinclpvYlmtvctcaccbinph thuc. thc hin iu ny cc lnh ODE trong qu trnh gii phng trnhs gi rahm F =odefile(t,Y), trong t l dy s v hng, Y l vc t ct v kt qua ra ca hm l mt vc t ct. Ch rng tp ODEphi chp nhn cc i s t v Y cho d khng dng n cc i s ny. Trong trng hp n gin tp ODE c vit dng: function F = odefile(t,y) F = < chn mt hm ca t v (hoc) y y. >; V d: giiphngtrnh2-4cchuynthnhdngchun2-8,chngta cn phi vit Odefile nh sau: function F=Ptvp(t,Y) F(1,1)= Y(2); F(2,1)=Y(3); F(3,1)=(exp(30*t)*sin(10*t)-Y(1)-2*exp(15*t)*Y(3))/(1+cos(t)^2) V ghi vo tp c tn l Ptvp.m c. Gi lnh ODE Matlabcungcpchochng ta 7 lnh gii phng trnh vi phn khc nhau. c im v phm vi s dng ca cc lnh ny c dn ra trong bng 2-1: Lnh Kiu bi ton Bc chnh xc Phm vi s dng ode45Khng cngTrung bnh Thng dng nht, hay dng cho ln th u tin ode23Khng cngThpDng c lng th sai s ode113Khng cngthp n cao Dng khi yu cu v sai s tng i nghim khc hoc khi tnh ton trnmt tp ODEcn nhiu thi gian tnh ton.. 219ode15sCng Thp n trung bnh Dng gii h cng hoc khi c ma trn cng ode23sCngthp Dng c lng sai s khi gii cc h cng hc khi c ma trn khi lng hng s. ode23t Cng trung bnh Thp Nu bi ton ch hi cng v khi cn ligii khng c gim chn. ode23tbCngThp S dng c lng sai s khi gii cc h cng hoc khi c ma trn khi lng. Bng 2-1: Cc lnh gii phng trnh vi phn trong Matlab Tt c cc lnh ny u c chung mt cch s dng. C php n gin ca chng l: [t,Y] = solver('F',tspan,y0) Trong : Solver l tn lnh ODE (v d nh ode45, ode15s ...) 'F' l tn ca tp m-file m t h phng trnh vi phn y0 l vc t cc iu kin u (cc iu kin u phi t trong mt vc t ct) tspan:xcnhkhongtchphn:tspancthlvctchaigi tr: gi tr u tin quy nh thi gian bt u v gi tr th hai quy nh thi gian kt thc qu trnh tnh ton. Nu tspan l mt vc t nhiu phn t, n s quy nh cc mc thi gian cn xut