Tong Quan Ve Robot Cau Truc Song Song Va Phan Loai 7884

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Tng quan v Robot cu trc song song v phn loiTNG QUAN V ROBOT C CU TRC SONG SONG1.1 Gii thiu chung v Robot1.1.1 Lch s ra i v pht trin RobotT thp nin 50, cng vi s pht trin ca k thut iu khin theo chng trnh s NC (Numerical Control) vi s h tr ca cc c cu Servo v cc h in ton (Computation), tng kt hp iu khin NC vi cc c cu iu khin t xa c hnh thnh v trin khai nghin cu. Vo gia nhng nm 50, bn cnh cc tay my chp hnh c kh, xut hin cc loi tay my chp hnh thy lc v in t nh tay my Minotaur I hoc tay my Handyman ca General Electric. Nm 1954 George C.Devo thit k mt thit b c tn l C cu bn l dng chuyn hng theo chng trnh. n nm 1956 Devol cng vi Joseph F.Engelber, mt k s cng nghip hng khng, to ra loi Robot cng nghip u tin nm 1969 cng ty Unimation mi bt u c li nhun t sn phm Robot u tin ny. T nm 1972 bt u thi k ca cc Robot th h th hai: Robot c iu khin bng my tnh c cc c quan cm xc l cc cm bin lin h ngc. i din cho th h ny l Robot Shakey ca vin nghin cu Stanford. N l s th hin tng hp ca cc thnh tu Khoa hc - K thut Cng ngh C kh - in - in t - iu khin t ng - Tin hc. Robot bt u c ng dng rng ri trong hu ht cc lnh vc: t sn xut n nghin cu khoa hc,c y t v i sng hng ngy. Nm 1976 chic my cng c CNC s dng Microcomputer ra i. Trong giai on nhng nm 80 v 90 vi s pht trin v bo ca Khoa hc - K thut - Cng ngh, quy m sn xut v nghin cu khoa hc, th gii c tha hng nhiu thnh qu ca n, c bit v my tnh v tin hc lm thay i v cht cc trang thit b, t chc iu hnh sn xut v i sng nh: + Thit k vi s tr gip ca my tnh - CAD. + Sn xut vi s tr gip ca my tnh - CAM. + H thng sn xut mm, linh hot - FMS. + Sn xut tch hp my tnh - CIM. + Sn xut ng lc JIT. + iu hnh qun l cht lng ton din - TQM + Sn xut vi chin lc ton cu - WCM. Nhng nm u tin ca th k 21, Robot ang bc sang th h mi. T cc Robot iu khin theo kiu thao tc (Manual Input) ri n kiu Dn Dy, cc kiu iu khin ny c gi chung l iu khin c chng trnh -1-Tng quan v Robot cu trc song song v phn loi dn ng v cc Robot kiu ny thng c gi l Robot kho lo (Robot Habilis). Tip n l cc Robot c trnh iu khin thch nghi - thng minh, Robot c tr khn (Robot Spiens). S tin b ca Khoa hc - K thut - Cng ngh gn nh thuc mi lnh vc C hc - C kh - in - in t - iu khin t ng - My tnh - Tin hc - Sinh vt hc u c th hin trn s pht trin ca Robot. Nhng ng dng mi nht ca Robot vo y hc c th k nh Robot phu thut v thay th cc c quan hot ng ca con ngi, m phng cc loi sinh vt. Nhng kt qa tin b ca Khoa hc - K thut - Sn xut cho n nhng nm 1970 hnh thnh khoa hc Roboties v C - in t (Mechatronics), t cng bt u o to cc chuyn gia k thut thuc lnh vc Robot v C - in t. Trong nhng nm gn y, robot cng nghip ch yu c dng cho cc thao tc lp li nhiu ln v trong cc mi trng nguy him. Xu hng ca con ngi l ch to ra cc robot thng minh, gip vic nh, gip ngi tn tt,... Mc d c nhiu l lc pht trin robot thng minh, nhng cc loi robot c th m phng nhiu chc nng ca con ngi vn cn nhng hn ch nht nh, i hi s pht trin ca cng ngh v tr tu nhn to.1.1.2 Robot c cu trc song songa) Gii thiu chung Xut pht t nhu cu v kh nng linh hot ha trong sn xut, cc c cu Robot cng ngy cng pht trin rt a dng v phong ph. Trong nhng thp nin gn y, Robot cu trc song song c Gough v Whitehall nghin cu nm 1962 v s ch ng dng ca Robot cu trc song song c khi ng bi Stewart vo nm 1965. ng l ngi cho ra i mt bung (phng) tp li my bay da trn c cu song song. Hin nay c cu song song c s dng rng ri trong nhiu lnh vc. Loi Robot song song in hnh gm c bn my ng c ni vi gi c nh, dn ng theo nhiu nhnh song song hay cn gi l s chn. Thng s chn bng s bc t do, c iu khin bi ngun pht ng t trn gi c nh hoc ngay trn chn. Chnh l do ny m cc Robot song song i khi gi l cc Robot c b. Cc c cu tc ng iu khin ti ngoi, nn c cu chp hnh song song thng c kh nng chu ti ln. Do tnh u vit ca Robot song song nn ngy cng thu ht c nhiu nh khoa hc nghin cu, ng thi cng c ng dng ngy cng rng ri vo nhiu lnh vc: + Ngnh Vt l : Gi knh hin vi, gi thit b o chnh xc.-2-Tng quan v Robot cu trc song song v phn loi + Ngnh C kh : My gia cng c kh chnh xc,my cng c. + Ngnh Bu chnh vin thng : Gi ngten, v tinh a tnh. + Ngnh ch to t : H thng th ti lp t, bung tp li t. + Ngnh qun s : Robot song song c dng lm b n nh c t trn tu thy, cc cng trnh thy, trn xe, trn my bay, trn chin xa v tu ngm. gi cn bng cho ngten, camera theo di mc tiu, cho rada, cho cc thit b o laser, b n nh cho pho v tn la, bung tp li my bay, xe tng, tu chin. b) Mt s u nhc im ca Robot song song Nhn chung, tt c cc lai Robot c cu trc song song u c nhiu u im v c th c ng dng trong nhiu lnh vc, cc b m hnh my bay, cc khung kin trc c khp ni iu chnh, cc my khai thc m ... - u im : + Kh nng chu ti cao: cc thnh phn cu to nh hn nn khi lng ca cc thnh phn cng nh hn. + cng vng cao do kt cu hnh hc ca chng: Tt c cc lc tc ng ng thi c chia s cho tt c cc chn. Cu trc ng hc mt cch c bit ca cc khp lin kt cho php chuyn tt c cc lc tc dng thnh cc lc ko/nn ca cc chn. + C th thc hin c cc thao tc phc tp v hat ng vi chnh xc cao: vi cu trc song song, sai s ch ph thuc vo sai s dc trc ca cc cm c cu chn ring l v cc sai s khng b tch ly. + C th thit k cc kch thc khc nhau. + n gin ha cc c cu my v gim s lng phn t do cc chn v khp ni c thit k sn thnh cc cm chi tit tiu chun. + Cung cp kh nng di ng cao trong qu trnh lm vic do c khi lng v kch thc nh gn. + Cc c cu chp hnh u c th nh v trn tm nn. + Tm hot ng ca Robot c cu song song rt rng t vic lp rp cc chi tit cc nh ti cc chuyn ng thc hin cc chc nng phc tp, i hi chnh xc cao nh: phay, khoan, tin, hn, lp rp... + Cc Robot c cu song song lm vic khng cn b v c th di chuyn ti mi ni trong mi trng sn xut. Chng c th lm vic ngay c khi trn thuyn v treo trn trn, tng ... + Gi thnh ca cc Robot song song ng dng trong gia cng c kh t hn so vi my CNC c tnh nng tng ng. -3-Tng quan v Robot cu trc song song v phn loi - Nhc im: Tuy nhin cc Robot song song cng c nhng nhc im nht nh khi so snh vi cc Robot chui nh: + Khong khng gian lm vic nh v kh thit k. + Vic gii cc bi ton ng hc, ng lc hc phc tp... + C nhiu im suy bin (k d) trong khng gian lm vic. 1.2 Cu trc Robot song song1.2.1 Cu trc c cuCng nh cc Robot thng thng, Robot song song l loi Robot c cu trc vng kn trong cc khu (dng thanh) c ni vi nhau bng cc khp ng. S ng c cu tay my thng thng l mt chui ni tip cc khu ng, t khu ra (l khu trc tip thc hin thao tc cng ngh) n gi c nh. Cn trong Robot song song, khu cui c ni vi gi c nh bi mt s mch ng hc, tc l ni song song vi nhau v cng hot ng song song vi nhau. S khc nhau v s ng cng to nn nhiu c im khc bit v ng hc v ng lc hc.1.2.2 Khu, khp, chui ng v my trong c cu Robot song song- Khu : L phn c chuyn ng tng i vi phn khc trong c cu. Chng ta coi tt c cc khu l cc vt rn. iu lm cho vic nghin cu cc c cu, Robot c d dng v n gin hn. Tuy nhin, vi cc c cu tc cao hoc mang ti ln th hin tng n hi ca vt liu tr nn quan trng ng k v chng ta phi xt n. - Khp : L ch ni ng gia hai khu. Ty theo cu trc, mi khp hn ch mt s chuyn ng gia hai khu. B mt tip xc ca mi khu ti khp gi l mt thnh phn khp. Hai thnh phn khp to thnh mt khp ng. Khp ng c th phn thnh khp thp v khp cao ty thuc vo dng tip xc. + Khp thp: Nu hai thnh phn tip xc l mt. + Khp cao: Nu hai thnh phn tip xc l im hoc ng. C 6 loi khp thp v hai loi khp cao c bn thng dng trong cc c cu my v cc Robot, l: + Khp quay (Revolute Joint - R) : Khp li chuyn ng quay ca khu ny i vi khu khc quanh mt trc quay. Ngha l khp quay hn -4-Tng quan v Robot cu trc song song v phn loi ch 5 kh nng chuyn ng gia hai thnh phn khp v c mt bc t do . Khp quay thng c gi l khp quay bn l. + Khp lng tr (Prismatic Joint - P) : Cho php hai khu trt trn nhau theo mt trc. Do , khp lng tr hn ch 5 kh nng chuyn ng tng i gia hai khu v c mt bc t do. Ngi ta cng thng gi khp lng tr l khp tnh tin. + Khp tr (Cylindrical Joint - C) : Cho php hai chuyn ng c lp, gm mt chuyn ng quay quanh trc v chuyn ng tnh tin dc trc quay. Do , khp tr hn ch 4 kh nng chuyn ng gia hai khu v c hai bc t do. + Khp ren (Helical Joint - H) : Cho php chuyn ng quay quanh trc ng thi tnh tin theo trc quay. Tuy nhin chuyn ng tnh tin ph thuc vo chuyn ng quay bi bc ca ren vt. Do , khp ren hn ch 5 chuyn ng tng i hai khu v cn li mt bc t do. + Khp cu (Spherical Joint - S) : Cho php thc hin chuyn ng quay gia hai thnh phn khp quanh tm cu theo tt c cc hng, nhng khng c chuyn ng tnh tin gia hai thnh phn khp ny. Do , khp cu hn ch 3 kh nng chuyn ng v c ba bc t do. + Khp phng (Plane Joint - E) : Cho hai kh nng chuyn ng tnh tin theo hai trc trong mt tip xc v mt kh nng quay quanh trc vung gc vi mt phng tip xc. Do , khp phng hn ch 3 bc t do v c ba bc t do. + Khp bnh rng phng (Gear Pair - G) : Cho hai bnh rng n khp vi nhau. Cc mt rng tip xc y nhau, chng thng trt trn nhau. Do , khp bnh rng phng hn ch 4 kh nng chuyn ng tng i gia hai thnh phn khp, cn li hai bc t do. + Khp cam phng (Cam Pair - Cp) : Tng t nh khp bnh rng, hai thnh phn khp lun tip xc vi nhau. Do , khp cam phng c hai bc t do. Khp quay, khp lng tr, khp tr, khp ren, khp cu v khp phng l cc khp thp. Khp bnh rng phng v khp cam phng l cc khp cao. - Chui ng : L tp hp cc khu c ni vi nhau bng cc khp ng. Robot ni tip c cu trc chui h, cn Robot song song c cu trc l chui kn. Chui ng hc c gi l c cu khi mt trong cc khu l gi c nh. Trong c cu c th c mt hoc nhiu khu c n nh l khu dn vi cc thng s cho trc. S chuyn ng ca cc khu dn l c lp, s chuyn ng ca cc khu khc s ph thuc vo chuyn ng ca khu dn. C cu l mt thit b truyn chuyn ng t mt hay nhiu khu dn ti cc khu khc.-5-Tng quan v Robot cu trc song song v phn loi - My mc : Gm mt hoc nhiu c cu, cng vi cc thnh phn in, thy lc v/hoc kh nn, c dng bin i nng lng bn ngoi thnh c nng hoc dng nng lng khc. C cu chp hnh ca h thng robot l c cu. c cu ny tr thnh my cn phi c b iu khin da trn b vi x l, b m ha v/hoc cc cm bin lc, cng vi cc b phn khc, chng hn h thng quan st, phi hp vi nhau chuyn i nng lng bn ngoi thnh cng hu ch. Mc d my c th gm mt hoc nhiu c cu, nhng c cu khng phi l my, do khng thc hin cng, ch c chc nng truyn chuyn ng.1.2.3 Bc t do ca Robot cu trc song songXt hai vt th (hay hai khu) A v B ri nhau trong khng gian. Gn vo A mt h ta cc Oxyz (Hnh I.1) th B s c 6 kh nng chuyn ng tng i so vi A, hay ni cch khc l gia A v B c 6 kh nng chuyn ng tng i, ta gi l 6 bc t do tng i. Cc kh nng chuyn ng c lp l : - Cc chuyn ng tnh tin dc cc trc Ox, Oy, Oz, k hiu l Tx, Ty, Tz - Cc chuyn ng quay quanh cc trc Ox, Oy, Oz, k hiu l Rx, Ry, RzZ Tz RzBA Ry Rx X Tx Ty YHnh 1.1: Cc kh nng chuyn ng tng i gia hai vt th nh ngha: Bc t do ca c cu l s thng s c lp tuyn tnh cn thit hon ton xc nh v tr ca c cu. Ta c th xc nh c biu thc tng qut v s bc t do ca c cu theo s khu, s khp, v kiu khp trong c cu. thng nht cho vic tnh ton s bc t do ca c cu,ta s dng cc k hiu sau: ci: S rng buc ca khp i. -6-Tng quan v Robot cu trc song song v phn loi F: S bc t do ca c cu. fi: S chuyn ng tng i c php ca khp i. j: S khp trong c cu. ji: S khp vi i bc t do. L : S vng c lp trong c cu. n : S khu trong c cu, k c khu c nh.: S bc t do trong khng gian lm vic ca c cu.Ta gi thit tt c cc khp u l hai chiu, khp ba chiu c coi l hai khp hai chiu, khp bn chiu c coi l ba khp hai chiu, ... Ngoi ra, cn gi thit mt gi tr c dng cho cc chuyn ng ca tt c cc khu chuyn ng, chng u vn hnh trong khng gian lm vic, do =6 i vi c cu khng gian, v = 3 i vi c cu phng v c cu cu. Gi tr bc t do ca c cu chnh bng s bc t do ca tt c cc khu hot ng tr i s rng buc bi cc khp. Do , nu cc khu u t do, s bc t do ca c cu n - khp , vi mt khp c nh, s bng ( n-1 ). j Tuy nhin, tng cc rng buc ca cc khp l bng i =1 ci , do gi tr bc t do ca c cu c tnh theo phng trnh:f = (n 1) cii =1j(1.1)S rng buc ca mt khu v s bc t do ca khu bng thng s chuyn ng , do : = ci + fiDo tng cc rng buc ca cc khu l:(1.2)j c = ( f ) = j fi =1 i i =1 i i =1jji(1.3)Thay phng trnh ( 1.3) vo phng trnh (1.1) ta c: f = (n j 1) fii =1 j(1.4)u Phng trnh (1.4) c gi l tiu chun Gr && bler hoc Kutzbach.u Tiu chun Gr && bler ng cho trng hp cc rng buc ti cc khp l c lp v khng d. V d mt khp quay cu lin kt chui vi khp quay c trc xuyn qua tm ca khp cu s to ra mt bc t do tha. Kiu bc t do ny gi l bc t do th ng, cho php khu trung gian quay t do quanh trc c xc nh t hai khp . Mc d khu trung gian c kh-7-Tng quan v Robot cu trc song song v phn loi nng truyn lc hoc momen v chuyn ng cho cc khu khc, nhng n khng c kh nng truyn momen cho trc th ng. Ni chung, cc khu hai chiu vi cc cp S-S, S-E, E-E u c bc t do th ng. Bng sau thng k s phi hp cc khu loi hai chiu vi cc khp S-S, S-E, E-E vi cc khp cui cng ca chng c mt bc t do.STT Kiu 1 2 3 S-S S-E E-EBc t do th ng (tha) Quay quanh trc i qua cc tm khp cu. Quay quanh trc i qua tm khp cu v vung gc vi mt phng ca khp phng Trt dc trc song song vi giao tuyn to bi cc mt phng ca khp phng. Nu hai mt phng ny song song s c ba bc t do th ng ( tha ).Bc t do th ng khng th truyn momen v chuyn ng cho trc th ng. Khi c mt khp loi ny tn ti trong c cu, cn tr i mt bc t do t phng trnh tinh bc t do. Gi s, fp l s bc t do th ng trong c cu th s bc t do ch ng trong c cu l: f = (n j 1) fi f pi =1 j(1.5)V d: C cu khng gian Stewart - Gough.Bn m y ng S Kh p cuP Kh p l ng trS Kh p cu c nh-8-Tng quan v Robot cu trc song song v phn loi Hnh 1.2: C cu khng gian Stewart - Gough L c cu khng gian gm c mt bn my ng c ni vi c nh bi su chn trt thng qua cc khp cu. Mi chn c to thnh t hai khu, v c ni vi nhau bng khp lng tr. Cu trc ny c gi l cu trc S - P - S. Do s phi hp S - P - S, nn mi chn c mt bc t do tha. T hnh v ta c : =6, n=14, ji =6, j3 = 12, fp =6 S bc t do ca c cu c tnh theo phng trnh (1.5) l : f =6(14 - 18 - 1) + (12x3 + 6) - 6 = 6 S dng phng trnh (1.5) tnh bc t do cho c cu khng gian c ni ti gi tr cho tt c cc khu di chuyn, khi tnh bc t do cho c cu phng v c cu cu c xem nh h con ca h khng gian nn cn phi ch ti thng s ny. c bit, =3 vi c cu phng v c cu cu, cn vi c cu khng gian th =6.u Ni chung tiu chun Gr && bler c f > 0 th c cu c f bc t do. Nu f=0, c cu khng c bc t do, ngha l c cu lc ny tr thnh gin tnh nh. Nu f < 0, c cu s c s rng buc tha. Tuy nhin, cng c cc c cu khng tun theo tiu chun Grubler. Cc c cu ny i hi chiu di khu c bit t c tnh linh ng cao c gi l c cu thng rng buc.i vi cc c cu vng kn v c cu chp hnh, s lng v v tr cc khp pht ng phi c chn mt cch cn thn sao cho khu tc ng cui phi c iu khin theo yu cu. Ni chung s khp pht ng phi bng s bc t do ca c cu, v v tr ca khp pht ng phi c chn sao cho chng c th to thnh tp hp cc to c lp. Nu s lng khu pht ng nh hn s bc t do th chuyn ng ca cc khu ny phi theo to tng ng cc rng buc ng hc ca chng. Mt robot c bc t do d th cho php iu khin linh hot hn.1.2.4 Cc bi ton c bn v robotRobot l mt ngnh khoa hc v cng ngh truyn thng, kt hp vi l thuyt v ng dng ca cc h thng robot. Vic nghin cu bao gm c hai vn l nghin cu l thuyt v ng dng, nhng vn chia ra thnh cc lnh vc : cng tc thit k robot, c hc c cu, thit k qu a v iu khin, cng tc lp trnh v tri thc cho my... C hc l mt nhnh khoa hc nghin cu cc vn v nng lng, lc v tc dng ca chng i vi chuyn ng ca h thng c kh. Vic nghin cu bao gm hai vn c quan h vi nhau l : ng hc v ng lc hc. a) ng hc ng hc nghin cu cc c trng ca chuyn ng m khng quan tm n nguyn nhn gy ra chng nh lc v mmen. S thay i ca cc khu-9-Tng quan v Robot cu trc song song v phn loi ca robot lin quan n hng v v tr ca khu chp hnh cui cng bi s rng buc ca cc khp. Nhng quan h ng hc l trng tm ca vic nghin cu ng hc robot. Bi ton phn tch ng hc c chia thnh hai dng : Bi ton ng hc thun v Bi ton ng hc ngc. Ba ton ng hc thun : T cc thng s v tr, vn tc v gia tc ca khu dn ,yu cu lp trnh tnh ton v tr v hng, vn tc v gia tc ca im tc ng cui cng nh khu trung gian bt k. Bi ton ng hc ngc : T yu cu v v tr v hng, vn tc v gia tc ca khu tc ng cui, tm ra cc thng s tng ng ca cc khu trc (bi ton ng hc ngc). b) ng lc hc ng lc hc nghin cu v quan h gia cc lc tc dng vo c cu (lc, ti trng v ma st...) v chuyn ng ca c cu. ng lc hc robot l vn rt phc tp v hin nay ang l i tng c nghin cu tip tc.1.3 Phn loi robotRobot c th c phn loi theo nhiu tiu chun, s bc t do, cu trc ng hc, h thng truyn ng, dng hnh hc ca chi tit gia cng, cc c tnh chuyn ng... - Phn loi theo s bc t do S phn loi robot thng dng l theo s bc t do. Mt cch l tng, c cu chp hnh phi c 6 bc t do x l i tng mt cch t do trong khng gian ba chiu. Theo quan im ny, robot a nng c 6 bc t do, robot d c hn 6 bc t do v robot thiu c t hn 6 bc t do. Robot d c thm mt bc t do di chuyn qua cc chng ngi vt hoc vn hnh trong cc khng gian hp. Mt khc, i vi mt s ng dng c bit, chng hn lp gip cc chi tit trn mt phng, robot bn bc t do l .- 10 -Tng quan v Robot cu trc song song v phn loiHnh 1.3: Robot loi Fanuc 4 bc t do2F3 3 2 FB1B1AA- 11 -Tng quan v Robot cu trc song song v phn loi Tay my REVOLUTE Tay my POLARF23A1B1B A2Tay my CARTERSIANTay my CYLINDRICALB 21F3ATay my SCARA Hnh 1.4: M hnh mt s loi tay my thng dng - Phn loi theo cu trc ng hc Robot c gi l robot ni tip nu cu trc ng hc c dng chui vng h, robot song song nu c chui vng kn, v robot lai nu c c chui vng h v vng kn. - Phn loi theo h thng truyn ng C ba h truyn ng ph bin l in, thu lc, v kh nn c dng cho robot. Hu ht cc c cu chp hnh u s dng ng c bc hoc ng c tr ng DC, do chng tng i d iu khin. Tuy nhin, khi cn tc cao v kh nng mang ti cao, thng dng truyn ng thu lc hoc kh nn. Nhc im ca truyn ng thu lc l kh nng r r du. Ngoi- 12 -Tng quan v Robot cu trc song song v phn loi ra, truyn ng kh nn c tnh linh hot kh cao. Mc d truyn ng kh nn sch v nhanh nhng kh iu khin do khng kh l lu cht nn c . Trong c cu ni tip, ni chung mt b tc ng c dng iu khin chuyn ng ca tng khp. Nu tng khu chuyn ng c truyn ng bng mt b tc ng lp trn khu trc thng qua hp gim tc, s dch chuyn ca khu ny v mt ng hc l c lp vi khu khc, y l c cu chp hnh ni tip qui c. Mt khc, nu mi khp c truyn ng trc tip bng b tc ng khng c hp gim tc, c cu c gi l c cu chp hnh truyn ng trc tip. Vic dng hp gim tc cho php s dng ng c nh hn, do lm gim qun tnh ca c cu chp hnh. Tuy nhin, lch khp ca cc bnh rng trong hp gim tc c th gy ra sai s vi tr b phn tc ng. K thut truyn ng trc tip khc phc c vn bnh rng v c th tng tc cho c cu chp hnh. Tuy nhin, cc ng c truyn ng trc tip tng i ln v nng. Do , chng thng c dng truyn ng khp th nht ca c cu chp hnh, ng c c lp . Ni chung, ng c cng c th c np truyn ng khp th hai hoc khp th ba thng qua ai kim loi hoc khu thanh y. Mt s c cu chp hnh s dng b cc bnh rng, xch v a xch truyn ng cc khp. Khi s dng h thng truyn ng ny cho c cu chp hnh qua nhiu khp, dch chuyn ca khp s ph thuc ln nhau. Cc c cu chp hnh kiu c gi l vng kn.- Phn loi theo dng hnh hc khng gian lm vicKhng gian lm vic ca c cu chp hnh c xc nh l th tch khng gian u tc ng c th vi ti. Ni chung, thng s dng hai nh ngha v khng gian lm vic. Th nht l khng gian c th vi ti, th tch khng gian trong c cu tc ng c th vi ti tng im theo t nht l mt chiu. Th hai l khng gian linh hot, th tch khng gian trong c cu tc ng c th vi ti tng im theo mi chiu c th. Khng gian linh hot l mt phn ca khng gian c th vi ti. Mc d y khng phi l iu kin cn, nhng nhiu c cu chp hnh ni tip c thit k vi ba khu u di hn cc khu cn li. Do ba khu ny c dng ch yu thao tc v tr, cc khu cn li c dng iu khin hng ca u tc ng. V l do , ba khu u c gi l cnh tay, cc khu cn li c gi l c tay. Tr cc c cu chp hnh vi s bc t do ln hn 6, cnh tay thng c ba bc t do, c tay c 1-3 bc t do. Hn na, b c tay thng c thit k vi cc trc khp ct nhau ti mt im chung c gi l tm c tay. B cnh tay c th c nhiu kiu cu trc ng hc, to ra cc bin lm vic khc nhau, c gi l vng khng gian lm vic. Khng gian do nh sn xut robot cung cp thng c xc nh theo vng khng gian lm vic.- 13 -Tng quan v Robot cu trc song song v phn loi Tay my c gi l robot tr nu khp th nht hoc khp th hai ca robot Decartes c thay bng khp quay(Hnh 1.4). Tay my c gi l robot cu nu hai khp u l khp quay khc nhau v khp th ba l khp lng tr (Hnh 1.4 - tay my SCARA). V tr tm c tay ca robot cu l tp hp cc ta cu lin quan vi ba bin khp ni. Do khng gian lm vic robot cu c gii hn theo hai khi cu ng tm. Tay my c gi l robot quay nu c ba khp u l khp quay. Khng gian lm vic ca robot ny rt phc tp thng c tit din hnh xuyn. Nhiu robot cng nghip l loi robot quay (Hnh 1.4 - tay my REVOLUTE).1.6 Mt s ng dng ca robot cng nghip.Mc tiu ng dng robot cng nghip nhm gp phn nng cao nng sut dy chuyn cng ngh, gim gi thnh, nng cao cht lng v kh nng cnh tranh ca sn phm, ng thi ci thin iu kin lao ng. iu xut pht t nhng u im c bn ca robot, l: + Robot c th thc hin c mt qui trnh thao tc hp l bng hoc hn ngi th lnh ngh mt cch n nh trong sut thi gian lm vic. V th robot c th gp phn nng cao cht lng v kh nng cnh tranh ca sn phm. Hn th, robot cn c th nhanh chng thay i cng vic thch nghi vi s bin i mu m, kch c sn phm theo yu cu ca th trng cnh tranh. + Kh nng gim gi thnh sn phm do ng dng robot l v gim c ng k chi ph cho ngi lao ng. + Vic p dng robot c th lm tng nng sut dy chuyn cng ngh. S d nh vy v nu tng nhp khn trng ca dy chuyn sn xut, nu khng thay con ngi bng robot th ngi th khng th theo kp hoc rt chng mt mi. + ng dng robot c th ci thin iu kin lao ng. l u im ni bt nht m chng ta cn lu tm. Trong thc t sn xut c rt nhiu ni ngi lao ng phi lm vic sut bui trong mi trng rt bi bm, m t, nng nc hoc n o qu mc cho php nhiu ln, thm ch phi lm vic trong mi trng c hi, nguy him ti sc kho con ngi, d xy ra tai nn .1.5 Phn loi robot song songMt robot song song c gi l i xng nu n tho mn cc iu kin sau:- 14 -Tng quan v Robot cu trc song song v phn loi + S chn bng s bc t do ca bn my ng. + S khp v loi khp trong tt c cc chn c sp xp ging nhau. + S khu hot ng v v tr ca khu hot ng trong tt c cc chn l nh nhau. Khi cc iu kin trn khng c tho mn th robot c gi l robot khng i xng. Ch rng robot i xng c s chn t do ( m ) bng s bc t do ( F ) v cng bng vi tng s vng L+1. Ta c: m = f = L +1 (1.6) (1.7) (1.8) (1.9)m j Ck = f ik =1mi =1Ck =1k= ( + 1) f f Ck Trong : m: S chn ca robot f : S bc t do ca robot. L: S vng ng c lp trong c cu. Ck : S kh nng ni ng ca chn, y cng chnh l s chuyn ng c th ca chn. i. fi : S kh nng chuyn ng ca c cu hay bc t do ca khp th j : S khp trong c cu, bao gm tt c cc khp. : S bc t do ca khng gian m c cu hot ng.1.5.2 Cc robot song song phngVi cc robot song song phng ta c =3, m =f =3 thay vo phng trnh (1.8) ta c: C1+C2+C3 = 4f -3 =9 ng thi phng trnh (1.9) lc c dng: 3 Ck 3- 15 -Tng quan v Robot cu trc song song v phn loi Do mi chn c ba bc t do trong cc khp to nn chng. Tm li, mi chn gm hai khu v ba khp , mi khp cn c mt bc t do khp. S dng khp quay v khp trt lm cp i khp, ta nhn c by loi chn c th chp nhn c, l RRR, RRP, RPR, PRR, RPP, PPR, v PPP. Do nu ta gii hn cu trc chn ca cc robot th ch c by loi thuc lp robot song song phng t do c th thc hin c.Hnh 1..5: Robot song song phng 3 bc t do vi cu trc chn RRRCFH EB chuy ng nP I R A BGP c nhDHnh 1.6: C cu chp hnh song song 3 PRP Hnh 1.5 minh ha c cu chp hnh song song phng ba bc t do dng cu trc chn 3 PRP; Hnh 1.6 minh ho c cu chp hnh song song 3 bc t do phng c cu trc nhnh 3 PRP, trong 3 trc khp quay vung gc vi mt phng chuyn ng trong khi cc trc khp lng tr nm trn mt phng chuyn ng.1.5.3 Cc robot song song cu- 16 -Tng quan v Robot cu trc song song v phn loi Cc c cu cu c ba bc t do. Do yu cu lin kt trong c cu chp hnh song song cu ging nh cc c cu chp hnh song song phng. Trong c cu chp hnh lin kt cu, loi khp c php l khp quay, tt c cc trc khp phi giao nhau ti mt im chung, l tm hnh cu, do cu trc nhnh duy nht c php l cu trc RRR. C cu chp hnh trn hnh 1.7 l c cu chp hnh song song cu 3RRR, 3 bc t do.B1Bn m y ngB3 6 C3 3 54 C1 B21 O A1 c nh A2 2 C2A3Hnh 1.7: C cu chp hnh kiu cu 3 RRR. Ch , mt khp cu c th c lp tm ca c cu chp hnh song song cu. Tuy nhin, khp cu nh th ch c th l khp th ng, v cc b tc ng hin hu khng th truyn ng cho khp . V th, nu dng mt khp cu, cn c thm 3 nhnh tc ng song song vi b chuyn ng. Trong trng hp ny, s nhnh, k c nhnh vi khp cu th ng bng 0, khc vi s bc t do.1.5.4 Cc robot song song khng giani vi robot song song khng gian, thay = 6 vo phng trnh (1.8) v (1.9) ta c:Ckmk= 7F 6(1.10) (1.11)6 Ck FGii ng thi (1.10) v (1.11) vi cc s nguyn dng Ck , k=1,2,3...C th phn loi robot song song khng gian ng vi s bc t do v lin kt c nu trn bng:- 17 -Tng quan v Robot cu trc song song v phn loi Bc t do F S vng L Tng cc bc t do khp lin kt Ck,k=1,2,3...f2 1 8i4,4 5,3 6,232155,5,5 6,5,4 6,6,34 5 63 4 522 29 366,6,5,5 6,6,6,4 6,6,6,6,5 6,6,6,6,6,6S khu trong mi nhnh c th nhiu bng tng tt c cc khp t do v bng s ni ng yu cu. S khu l ln nht khi tt c cc khp u l khp mt bc t do. Hnh 1.8 m t mt s cu trc chn. Hnh 1.8a l chn 4 bc t do. Hnh 1.8b-e l cc chn 5 bc t do. Hnh 1.8f-h l cc chn 6 bc t do. Ch , mi chn trn cc hnh 1.8e,f v h c mt bc t do d, cn chn trn hnh 1.8g c 2 bc t do d. Nu cn cc nhnh c cu trc ng hc, cc lin kt (4,4),(5,5,5) v (6,6,6,6,6,6) l cc cch b tr thng hay s dng trong cc c cu song song 2,3 v 6 bc t do.- 18 -Tng quan v Robot cu trc song song v phn loiBn m y ng Bn m y ng Bn m y ngR C RGi (a)S R PGi (b)S R CGi (c)Bn m y ng Bn m y ngS R R R RGi (d) (e) GiSBn m y ngBn m y ngBn m y ngS PS CS S RGi Gi (h)SGi (f)S(g)Hnh 1.8 Tm kiu chn hay s dng1.5 kt cu ca Robot song song 3 RPSTrong ti, yu cu tnh ton v m phng s Robot song song 3 RPS, thng c thit k mang phi gia cng v c lp t trn bn g phi ca my phay. Ba chn vi chiu di c th thay i c iu khin bi cc ng c s dn ng cho b di ng mang phi chuyn ng theo qu o xc nh trc. Hai u ca cc chn ny c lin kt vi c nh v b di ng bng cc khp cu. u im ca loi Robot ny l khi lng nh, cu trc gn nh, cng vng cao, c 3 bc t do v chnh xc cao.- 19 -Tng quan v Robot cu trc song song v phn loi Tt c cc thnh phn c kh c la chn v thit k cng nh gn cng tt v khng c khe h theo chiu dc trc ca cc chn, cc chn c iu khin ca Robot c dn ng bng cc c cu chp hnh tuyn tnh. Hnh 1.9 m t s ca robot ny.1 : Bn di ng 1 2 3 6 2 : ng tru t trong 3 : ng tru t ngoi 4 : Kh p quay 5 : M c t nh 6 : Kh p cu 4 5Hnh 1.9: C cu chp hnh song song 3 RPS - Chi tit 1 : Bn di ng c 3 bc t do trong khng gian, trong trng hp c th y l phn b mt dng g dng c ct kim loi (u dao phay,...) hoc lp g phi (thc chia , kp phi gia cng ...) c dng tam gic (thng l tam gic u). Trn bn di ng s lp t cc loi g kp chi tit hoc lp t cm ng c - i dao gia cng. Bn c thit k c cc l, cht nh v lp g. g c lp cht trn bn di ng bng cc bulng. - Chi tit 2: L mt phn ca chit tit thanh trt lng, ng trt trong. Tt c cc ng trt trong c dng thanh tr c. Khp trt c truyn ng bng c cu chp hnh s dng ng c servo, b truyn ng v cm c cu trc vt - ai c bi. Cc chn ca Robot c ni vi b di ng v c nh bng cc khp cu 6. - Chi tit 3 : L mt phn ca chi tit thanh trt lng, ng trt ngoi. Tt c cc ng trt ngoi c dng hnh tr rng. - Chi tit 4 : Khp quay, ni chn vi c nh. - Chi tit 5 : Mt c nh, c dng tm phng trn. B c nh c lp t trn bn g chi tit ca my phay hoc c th c lp t c nh trn mt vt khc. Trn c nh c gia cng cc l phc v, vic c nh trn bn g hoc cc vt khc bng cc bulng. Trn c nh cn c gia cng cc rnh nh v phc v cng tc cn chnh, lp t Robot. - Chi tit 6 : Khp cu, ni chn vi bn my di ng.- 20 -