Dự báo rung động trong quá trình mài nhờ phân tích tín hiệu lực mài

NGHIEN CUlU - TRAO OOl DONG TRONG QUA TRJNH MAI NHO PHAN TiCH TJN HIEU LLPC MAI \JDU B A O R U N G IN-PROCESS CHATTER PREDICTION BY ANALYSIS OF CUTTING FORCE SIGNAL ThS Ph?m Vfl Dung', GS,TS B4o V5n Hiep' 'Truong D?i hpc Kinh tS Ky thujt C6ng nghiep 'Hoc vien Ky thuSt Quan su TOM TAT Rung dpng Id trgng thdi gidi hgn cua tu dao dpng qud trinh gia cong Id nguyen nhdn chinh hgn chi ndng suit vd chdt lupng chi tidt gia cong Vi vdy, cdc cong trinh nghien euu hifn co diu tgp trung vdo phdt hipn, nhgn dgng, trdnh, ngdn ngua, gidm hogc logi trif rung dpng Gidm sdt rung dpng qud trinh gia cong duac tap trung vdo nhgn dgng hodc nhdn biet rung dpng nha cdc ky thudt cdm bien vd xu ly du lieu Tic giifa the ky tru&c, hdng logt phucmg phdp phdt hien vd rung dpng dd dupc dexudi Moi phmmg phdp co uu, nhuffc diem rieng Bdi bdo ndy trinh bdy phucmg phdp, dijra tren quan he giiia lyre mdi vd cdc thong so rung dpng Kit qud nghien euu dd chi ra, tin hieu luc cdt khong chi giup phdt hien rung dpng md cdn du bdo no truac xdy Jix khoa: Rung dpng, luc mdi, dao dpng, gia cong, gidm sdt qud trinh Chatter is thecritical self-excited vibration that occurs during machining operations and become a major cause of limitation to productivity and part quality That's the reason why, existent research works on chatter is focused on detect, identify, avoid, prevent, reduce, or suppress chatter In-process chatter monitoring is focused on identifying or recognizing chatter through the use of several sensor technologies and signal treatment From middle of last century, a lot of methods for chatter detectionand measurement has been proposed Each of them have their own advantage and disadvantage.In this paper, Ihe method based onrelations between grinding force and chatter parameters have been investigated Results show that with the help ofgrindingforce signal we not only can detect but also predict chatter before it occurs Keywords: Chatter, grinding force, vibration, machining process monitoring ISSN 0866-7056 TAPCHlCOKHlVl£TNAM,Sa 10nam2015 www.cokhivietnam.vn NGHIEN cufu-TRAO D | l.DATVANDE ddng Clia luc cit va tiep tiic tai smh (regeneration) sdng bd mat cac chu ky sau Ndu bien Tru vii trudng hgp dac bidt, nhu cit cd tu dao dong tang d^n ngudng nhat dinh thi hd trg cua sidu am (Ultrasonic Assisted Machin- qua trinh cit dugc coi li mit dn dinh, rung ddng ing - UAM), dao ddng (vibration) gia cdng (chatter) xay la hi$n tugng cd hai: gSy sai sd gia cdng, l^m xau chit lugng bd mat, tang mdn dung cu cat, Mudn nang cao cac chi tidu kinh td - ky thuSt cua qui trmh gia cdng phai chdng dao ddng Dao dgng phat smh mdt each tir nhien qua trinh cat, khdng thd tranh dugc Khi dao dpng d gidi h£in cho phep, kidm soat dugc thi qua trinh gia cdng dugc xem la dn dinh Trong tinh hudng Hinh 1: Mo hinh tu dao dong ngugc lai, qua trinh dugc xem la mit dn dinh, rung ddng (chatter) xay Bidn phap chdng dao Hmh 1, minh hoa hidn tugng tai smh dgng cit ggt la phat hien, nhin dang dao dgng, han che dao ddng pham vi cho phep, tu dao ddng mai phing Bd mat ly tudng dugc bidu didn bing dudng net dut Be mat thuc phdng ngiia xay rung ddng cd dang sdng Chiing khac sai sd hinh hgc h(s) Khi mai ldp thu i, chidu sau cat thuc Cd nhidu bidn phap phdng ngira nmg a(s) la khoang each giiia be mat ldp trudc dd dgng, dd cd cac bien phaptii\idgng (passive) lai va bd mat viia duoc tao va cac bidn phap chii ddng (active) [1], [7] Bai bao dd cSp ddn mdt nhiJng bidn phap chu dgng: giam sat true tuydn dao dgng (on-line a(s)=a^+h^_/s)-h/s) = a^ + h(s) (1) vibration monitoring) dd phat hien hoac du bao trudc kha nang xay rung ddng Tii dd, hoac Dao ddng tai sinh khdng phai bao hidu cho ngudi vSn hanh sua da, didu chmh phin tinh a^ ma phan ddng h(s) Tit so chd dd cit, hoac cap tin hieu cho he thdng tu dd khdi hinh 1[2], cd: ddng sua da hoac cho bg didu khien thich nghi h(s)=h,Js)-y(s)(l-e'') (2) dieu chinh chd cat KHAI QUAT VE RUNG DQNG VA GIAM SAT RUNG DQNG 2.1 Khai quit ve rung d^ng mM Trong dd, T (s)- chu ky quay cua true da Luc cat phap tuydn bang tich cua luc don vi f^ (lire cat tinh cho mm^ tidt dien phoi) va didn tich tidt didn phoi Theo nguyen nhSn, cd loai dao ddng FJs)=ba(s)l (3) Dao ddng cuong biic (forced vibration) phat sinh cac ngudn nang lugng bdn ngoai vung Cudi cung, bidn dao dgng y(s) la dap cit Tu dao dgng (self-excited vibration) sinh ling dau ciia h? dao dgng tii ban than qua trinh cit, vi du dd sdng cua bd m^t da hay phdi, vSt lidu phdi khdng ddng ddu, cit gian doan, Chung kich thich su dao GO to) Ms'+Bs+K ISSN 0866-7056 TAP CHl CO KHl V I £ T NAM, Sd 10 nam 2015 www.cokhivietnam.vn NGHIEN Ciifu - TRAO DOI Cac bieu thuc tren cho thSy dp song be mat ban dau (h ,) kich thich su dao dgng cua luc cat (FJ va dao dong vi tri (y) giua dao va ph6i, roi tiep tuc tai sinh song (h) th^ nao Trong(4), G(j{o) the hien vai tro dp cung vtrng dpng (dynamic stiiShess) cHa th6ng cong nghe (HTCN), k§ ca Cling vung tiep xuc giua da va phoi Biiu thiic tSng hpp, thj hito dao dpng tai sinh nhu sau: y(')= V G(s)-bf.(\~e') h,Js) dao dong s6ng hi mat da gay n6n cung cao tucmg ling Tren thuc ti, bien dang ti6p xiic giua da va phoi, buac song kh6ng d6ng dSu va anh huong ciia dpng lire hpc HTCN n&i (6) chi CO y nghia dinh tfnh Tu dao dpng co dac tinh, la bien dp tang dan, nhung vi chiSu sBu lop cit tren phdi Ion hon sc vai lop mon ciia da nen bito dp dao dpng tai sinh song bS mat ph6i tang nhanh hon dao dpng tai sinh bj mat da, bito dp dao dpng (5) cuSng biic khong thay ddi (hinh 3) [8] Mlu s6 cua (5) thS hito phin , , Bien dp tvr dao ddng tang dto miic gidi dao dpng tai sinh: G(s) dong luc hoc ciia he ^*" ^''~' '*•' * ' ^' "^P """*» HTCN, bf - lop cat phai, bf e- - mon d i ' ' " ° ' ' " « ^ " * ' P*"*'^ Tan s6 dao ddng chiu anh huong ciia ca / =^.Dodd, song be mat phdi lln song b6 mat da; phu thupc vao van tdc ciia da, cila phdi va vao mdi tuong quan giiia buac song X^ va dp dai tidp xiic da - phoi 1^ Malkin [6] gpi dd la su lpc co hpc """ = 7 ^ (7) (mechanical filtering) Hinh bito diln phin tu dao ddng: phin thii nhlt song mat phdi C(S tan sd thip, bien dp ldn; phin thii hai song be mat da, tin sd cao, bito dp nhp Rung dpng gay nto sai sd kich thuoc, hinh hpc, giam chit lupng bS mat gia cdng, tang mdnhaygayvodimgcuvaphoi, Tit hinh cd thS xac dinh duoc tin sd dao dpng sdng bl mat phdi fiv va song b8 mat da f 21 '' (6) 21 Van tdc ciia da (v_) thudng ldn gip 50100 lan so vol van tdc cia phoi (vJ nto tin sd ISSN 0866-7056 TAP CHI CO KHI VIET NAM, S6 10 nam 2015 www.cokhivietnam.vn Thoi gan mai Hinh 3: Dien tiin cua dao ddng NGHIEN C U T U - T R A O D O I Khong the logi tru hoan toan dao dgng ma chi cd thd ngan ngiia nd phat triln rung dong bang each sua da hay didu chmh didu kidn gia cdng Vi vay, giam sat hire tuydn qua trinh phat trien cda dao dgng, dir bao trudc thdi didm xuat hidn rung ddng la giai phap ky thuSt tich cue Nhiing phan tich d trdn va phan tich tuong tu [8], [9] cho phep giai thich qua trinh dao dgng vi cac ydu td anh hudng ddn nd Tuy nhidn, bing ly thuydt rit khd tinh toan mdt each djnh lugng dd du bao rung ddng Cho ddn nay, hau hdt (ndu khdng mudn ndi la tit ca), cac he thdng giam sat va du bao rung ddng ddu it nhidu dua trdn thuc nghidm, dung tm hieu true tidp hay gian tidp dao ddng vao phan tich bien - tin sd cua tin hieu lire phip tuydn vi cua tin hidu AE, va chi rang tin hidu luc cat giiip phat hi?n rung d^ng trudc nd xay ra, cdn nhd AE chi phat hidn dugc rung dgng manh nd da xay ra, kem theo su xuat hidn ro rang ciia vdt (sdng) trdn bd mat chi tiet Kdt qua phin tich ciing cho thiy, theo thdi gian mai, bidn dao dgng tang dot bidn tai mgt tin sd nhit dinh Rung ddng xuit hidn da mdn tdi miic nhit dinh, sau dd mat di hidn tugng tu mii sac cua da 2.2 Cac phinmg phdp giam sat rung ddng Da cd nhieu phuong phap giam sat rung ddng dugc de xuat Bdn canh cac phuong phap true tidp dao ddng thudng gap, cac phuang phap gian tidp cang dugc quan tSm nghidn euu Rung ddng, luc cat, am thanh, mdn da, nhidt dd lidn quan mat thidt ddn nhau, vua la nguydn nhan, viia la kdt qua ciia ndn ngudi ta thudng dung dai lugng de quan sat dai lugng Dd khao sat anh hudng cua mdn da den rung dgng, Tanasescu [10] da so sanh phd tan sd - bidn Clia tin hidu am phat xa (Acoustic Emission - AE) mai vdi da sic vi da bi cun; da chira,biendo ddu tang dot bidn d cung tin sd va tang din da bi ciin Didu niy chiing td tin sd dao dgng khdng phu thudc vio tinh trang ciia da mi vao trang thai ddng luc hgc ciia HTCN Nhd phan tich Short Time Fourio: Transform (STFT) luc mai qua trinh mai, Chen (2006) [1] ciing phat hidn, dao ddng manh ludn xay d cac viing tin sd nhit dinh, cdn bidn dp thi tang din mdn da Gradisek, J (2003), [3] da thidt l^p hd thdng tu ddng phat hidn rung ddng dua Hinh 4: Song tren be mat vd tin hieu AE rung dgng Tren hinh li hinh anh bd mat mii vdi cac vet sang, tdi xen ke va sdng tren bd m^t phdi (chatter mark) ChMg xuat hien ddng thdi vdi sir tang dot bidn cua tin hidu AE rung dgng xayra [5] Tir cac vi du tren, cd the nit mgt so nhan xet sau: - Cd thd gian tidp nhai biet rung ddng nhd quan sat bd mat mai, thu am thanh, luc cat, nhidt dd viing cat, - Theo thdi gian, bidn dao ddng tang mdn da nhung tin sd thi khdng ddi, phu thugc vio dgng luc hgc ciia HTCN va tinh trang bd mat ciia da, phdi - Phan tich tin hidu lire cit vi tin hieu AE li hai phuong phap tin ciy dd giam sat rung dgng, nhung luc cit cho phep du bao trudc thdi didm rung ddng, AE chi cho phep nhin bidt rung dgng nd da xay '^ ISSN 0866-7056 TAP CHI CO KHI V I £ T NAM, Sd 10 nam 2015 www.coldiivietnam.vn NGHIEN Cdu - TRAO D | Han che cua cac nghito ciiu tren la mdi phan tich luc cat frong chi dd off-line, khdng thi hien kha nang tuong tac vol nguoi dung thoi gian thirc T H V C NGHIDM GIAM SAT RUNG DONG N H d DO LVC CAT ldn, tto sd thap), sdng be mat da (bidn dp nhd, tin so cao) va nhieu, chiia dao ddng cuong biic dang rang cua d mpi tin sd Ndu theo doi dd thi mpt khotog thdi gian thi se thiy gia tri luc cat (bien dp) tang mdn da, cdn tin sd dao ddng thi khong ddi (xem lai hinh 3) Nhu vay, kit hap tinh gia trj trung bmh Muc tito nghito ciiu cua chiing tdi la Clia luc cit theo thai gian va tin hilu phan tich giam sat true tuyto (on-line) mdn da dua trto DFT khdng chi cho phep theo doi gia tri lire tiic cac dtt lieu che dp mai va dtt heu luc cit, dp thdi ma cdn biet dupc tin sd, bien dp ciia cac nham be mjt, cd khao sat rung dpng dang dao ddng Neu thuc hien dupc dilu Thep npi dung bai bao, muc chi dd cgp dto thdi gian thuc thi cd thi theo ddi dien biln giam sat va du bao rung ddng nhd tin hieu lire cat va du bao dap ling diu (rung ddng, dp nham be mat, mdn da) 3.1 PhSn tich tin hieu lyc c i t Tin hidu lire cit la tin hieu roi rac, co nhieu phin, nhito y6u td tac dpng Thanh phin ttnh, duoc bito diln bing gia tri trung binh (thuong diing phuong phap trung binh blnh phuong - RMS) Cac thtoh phin dpng Hen quan dto cac dang dao dpng nhu da ndi muc 2.1 PIWWPPW » He diilt hi giam sat dupc ghep ndi theo so hinh 6, gdm: M ! 1 ; ! ! !J I'—j u Tr i «„T M 3.2 Nghien cihi thyc nglii|in i : : : : ! : i i ; i,—'- i i i i : i'^ i Mj^Lilj^L,^!:] (a) (b) Hinh 5: Tin hieu luc cdt theo thai gian (a) vd theo tdn so (b) Hinh 6: Sa dd ghep ndi he thdng gidm sdt mng dpng May mai phing ESG-4080AH (Dai Loan);phditiihpp kim Titan Ti-6Al-4V,kichthudc I00>! 10x20 mm; da Sx-60-G-Vl-400x40x 127 Tren hinh la trich doan ciia cung mot tm hi6u luc mii, nhung (a) la tin hieu thd (thu - He va xu ly tin hidu luc, gdm sensor true tiep tu d\mg cu do), duoc bidu diln theo thdi luc phin kilu 9257-BA cua Kistler (Thuy gian cdn (b) - dupc bito diln theo tin sd nhd Sl) ket hop vdi phin ciing DAQ kilu USB-6008 phep phan tich Fourier rod rac (Discrete Fourier va phan mim DAQ DasyLab Ver 10.0 (Data AcTransform - DFT) Ta thiy, tin hito theo thdi quisition System Laboratory), diu la sto phim gian khdng phto biet duac cac thinh phin dao cua NI (National Instruments - My) dpng, cdn tin hieu theo tin sd cho phep phto biet dao dOng tai sinh til sdng bl mat phdi (bi6n dp Che dp cit hong cac thi nghiem duac phin ISSN 0866-7056 T ^ P CHi CO KHI VIET NAM, Sd 10 nam 2015 www.cokhivietnam.vn NGHIEN cufu-TRAODdi bo theo quy hoach thuc nghiem dua tren ming (pause), chay (continue); dieu khidn chd hidn true giao L9, d diy chi trich thi nghidm dd thi va thoat chuong trinh minh hoa, iing vdi tdc da v =30m/s, tdc phdi v^=15m/ph, chidu siu cat a=0,04mm/htk OMI SAT ( M ) ( * C M O U E c u De danh gia kha nang hoat dgng ciia he thdng, chung tdi da tao mdt tinh hudng phuc tap hon binh thudng: thay doi lidn tuc chidu siu cat mai de tao s\r bidn dong ldn cua luc cit nhu hinh 7, dd hinh (a) the hidn ci tm hieu thd lin RMS, hinh (b) la dd thi 3D, ngoai bieu didn quan hd bidn - tin sd cdn cd true thdi gian Ta thay, theo thdi gian, bidn thay ddi, bam sat gia tri RMS hinh (a), ddng thdi cho thSy dii chieu sau cat thay ddi vi Hinh 8: Mdn hinh gidm sdt rung ddng da bi mdn nhung tan sd dao dgng van khdng ddi, the hien d cac dinh nhgn ludn xuat hidn tai mdt Didu dang quan tam chinh d day li dao tin sd nhit dinh Qua day cd thd kdt luan, he ddng tai smh sdng bd mat phdi ludn xuat thdng cd kha ning dap ung cac bidn dgng ciia hidn d tin sd 50-75Hz, dao dgng bd mat da d qua trinh thdi gian thuc khoing 275Hz Rung ddng dugc coi li xuat hidn F'n vugt qua nguong quy dinh Vdi he thdng da dugc thu thach trdn, chiing tdi da chmh thiic tien hinh thi nghidm vd DAINH GIA VA THAO LUAN KET QUA giam sat rung dgng Bii bao da trinh biy khai quat co sd ly thuydt vi thuc tidn vd nmg ddng vi giam sat nmg ddng qua trinh mai Dd li co sd dd thidt lap he thdng giam sat true tuydn (on-line) du bao rung ddng nhd phan tich tin hieu luc cat Kdt qua nghien euu da tai khang dinh, luc cat khdng chi cho phep nhan biet nmg ddng (a) (b) Hinh 7: Diin bien thoi gian thuc aia bien (a)mavdcdn du bao trudc nd xuat hidn Budc tidn mdi cua nghidn ciiu niy li da tao hd thdng da tdn sd (b) luc cdt chiic nang: luc, phan tich, giam sat, cinh bao Dd tang tidn ich six dung, mdt mat may rung ddng vi tuong tic true tuydn (on-line) vdi ao da dugc thidt kd nhu hinh 8, gom cac ngudi diing qua trinh mii Kdt qua cua s6 hidn thi tin hidu theo thdi gian ciia thinh ciing vdi kinh nghidm vd dieu khidn thich phin luc cit, dd thi FFT cua luc phap tuydn F'^, nghi [4] md kha nang thuc te vd giam sat toan dd thi dang cdt (bar graph) gia tri luc, Dac didn vi dieu khidn thich nghi qua trinh mii, bidt, trdn cdt F'_^ cd dat ngudng tdi da, hi khdng chi tinh ddn rung ddng mi ci cac thdng vugt thi chuydn sang mau dd, bao hieu diing sd khac, dac biet li mdn da va chit lugng bd mat '^ cit Ngoai ra, cdn cd cac phim didu khidn ngimg gia cdng.'J* ISSN 0866 ' 7056 T.AP CHi CO KHI VIET NAM, Sd 10 nam 2015 www.cokhivietnam.vn NGHIEN C U T U - T R A O D O I Ngiy nh£in bii: 14/8/2015 Ngiy phin bidn: 15/9/2015 Tii lidu tham khao: [1] Chen, X., Limchimchol, T (2006) Monitoring Grinding Wheel Redress-life UsingSupport Vector Mtxhines, International Joumal of Automation and Computing, 56-62 [2] Fukagawa, S., Fujimoto, H., Ishii, S., & Terada, Y, (2015), Chatter Suppression in NC Machine Tools by Cooperative Control of Spindle and Stage Motors lEEJ Intemational Workshop on Sensmg, Actuation, and Motion Control, 1-6 [3] Gradisek, J., Baus, A., Govekar, E., Klocke, F., & Grabec, I (2003), Automatic Chatter Detection in Grinding, hitemational Joumal of Machine Tools & Manufacture Vol 43,1397-1403 [4] Dao Van Hiep (2003), Nghien euu ung dying diiu khien thich nghi de ndng cao hieu qud gia cdng trin mdy cong cu dieu khien sd, Bao cao tong ket de tai cap Bp Quoc phong [5] Liu, G., Gong Y., Wang, W (2004) Study on On-line Monitoring Method for Grinding Quality, Key Engineering Materials, Vols 259-260, p 287-292 Retrieved from http://www.scientific.net [6] Malkin, S (1989) Grinding Technology Theory and Applications of Machining with Abravives, Ellis Horwood Limited [7] Quintana, G., Ciurana, J (2011) Chatter in machining processes: A review Intemational Joumal of Machine Tools & Manufacture 51, pp 363-376 [8] Rowe, W (2009) Principles of Modem Grinding Technology William Andrew [9] Shirvani, H., Yuan, L., & Jarvenpaa, V (2014) The Influence of Chatter Vibration on the Cylindrical Transverse Grinding Machine Spindle, The 2lst International Congress on Sound and Vibration, (pp 1-8) Beijing/China [10] Tanasescu, I., Ganatsios, S., Abalaru, A., Gheorghe, G., Dontu, O., & Besnea, D (2011) Autonomous System ofVibro-Acoustic Monitoring of the Grinding Process to Increase the Quality of the Processed Parts Control Eng & Applied Informatics, 14-19 ISSN 0866-7056 TAP CHf CO KHi VIET NAM 86 10 nam 2015 www.cokhivietnam.vn ... nghi h(s)=h,Js)-y(s)(l-e'''') (2) dieu chinh chd cat KHAI QUAT VE RUNG DQNG VA GIAM SAT RUNG DQNG 2.1 Khai quit ve rung d^ng mM Trong dd, T (s)- chu ky quay cua true da Luc cat phap tuydn bang... tin sd nhit dinh Rung ddng xuit hidn da mdn tdi miic nhit dinh, sau dd mat di hidn tugng tu mii sac cua da 2.2 Cac phinmg phdp giam sat rung ddng Da cd nhieu phuong phap giam sat rung ddng dugc... tin hieu AE li hai phuong phap tin ciy dd giam sat rung dgng, nhung luc cit cho phep du bao trudc thdi didm rung ddng, AE chi cho phep nhin bidt rung dgng nd da xay ''^ ISSN 0866-7056 TAP CHI CO