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Tgp chi Khoa hoc Truong Dgi hoc Cdn Tlia Phdn A- Khoa hoc Ty nhien, Cong nghi vd Moi irudng: 26 (2013 Tap chl Khoa hoc Tru'dng Oai hoc Can Thd website: sj.ctu.edu.vn DIEU KHIEN DAO D p N G HE T H A N H M A N H Ngd Quang Hidu' va Luong Hong Duy Khanh^ ' Bg mon Ky thugt Ca khi, Khoa Cdng nghe Trudng Dgi hoc Cdn Tha ^ Ldp Ky thudt Co di$n tir K3 7, Khoa Cong nghe, Trirdng Dai hgc Cdn Tho Thong tin chung: Ngdy nhdn: 08/01/2013 Ngdy chdp nhgn: 19/06/2013 Title: Vibration control of a flexible beam Tie khoa: H$ manh, dieu khien dao dgng dieu chi hinh dgng tin hi?u vdo Keywords: Flexible mechanical system, vibration control, input shopping control ABSTRACT In this paper, the control method for the vibrations suppression of a mechanical system is presented By changing the input signal of the system, the controller controls the load to the desired position in which the vibration is suppressed at the end of the motion To verify the effectiveness of the method, the model of a flexible system is used Vibration of the system has been significantly reduced under control action The experimental results of the control method are provided to show the efficiency of the control method TOM TAT Trong bdi bdo ndy, cdc phuongphdp diiu khiin ldm gidm dao ddng cua mgt hi ca hgc dugc trinh bdy.^ Bdng cdch thay dSi tin hiiu vdo cua H thong, bg dieu khiin se diiu khiin tdi din vj tri mong mudn vdi dao dong dugc triet tieu vdo cudi hdnh trinh Nhdm ddnh gid tinh hi0u qud cua phuang phdp mo hinh dao dgng cua hi manh dugc sic dyng Dao dgng cua h? thdng gidm di ddng ki dual tdc dong diiu khien Kit qud thyc nghiim cua mo hinh diiu khiin dugc trinh bdy di thdy dugc tinb hieu qud cOa phuong phdp dieu khiin GICWTHI^U Trong CO hgc dao dpng li chuydn dgng cd gidi hgn frong khdng gian, lap di lap lai nhidu Ian quanh vi fri cin bing Dao ddng ca hpc la mdt bidn thidn Udn tuc gida ddng nang va thd ning.Trong cic chuydn dgng tuong ddi giua cac chi tidt frong he ca ludn tdn tEti dao ddng Khi chi tidt chuydn ddng cang nhanh se t^o gia loc cang ldn, phat sinh moment quan tinh cang Idn lam ting bidn dao ddng the bj bidn dang, cong, ndt, gay Dao ddng he chi giam di cung cua he thdng phai vo cung ldn ho?c chuydn ddng cda cic chi tidt he phii rit cham Do dd vide giam dao dgng ciaa he ca hgc theo cac ydu ciu d^t bing cac bi?n phap ca la khdng hidu qua mOt so trudng hgp ya vide tdn tai cua dao ddng lam anh hudng ddn su chinh xac cua chuydn dpng^co ndn cin phii ap dyng cac bidn phap dieu khidn dd kidm soit, kh6ng che dao dpng Dao dgng cic chi tidt Iam giim tudi thg cic cong trinh xiy dyng nhu ciu, cdng, dudng cung nhu cac thidt bi frong he th6ng ca Vdi bidn dao dgng ldn cac chi tiet cd Cd rit nhidu phuang phap de didu khidn dao ddng nhung thudng dugc chia Iam hai nhdm phuong phap chinh: dieu khidn vdng hd I | A | | J I "^ Tgp chi Khoa hgc Truong Dgi hgc Cdn Tho Phdn A: Khoa hpc Ty nhien, Cor^ nghi va Moi irudng: 26 (20l3):53-60 va didu khidn hdi tidp Trong nhdm phuang phap dieu khien hdi tidp, dao dgng cda ddi tugng dugc ludng bang cam bien dao dong (gia tdc kd) va thidt bj didu khidn tinh toin, friet tidu dao ddng bing cac phin td tich cyc (damper) Khi vide ludng cac dao dgng la khd khan hoac khdng thd thuc hidn dugc thi nhdm phuang phap didu khidn vdng hd dugc ap dung Phuang phap niy lam thay ddi hiiih dang tin hieu diu vao cho he co hgc (input shaping) dua vio die tinh tin sdridngcua he Phirong phap thay ddi hinh dang tin hidu vao khdng ddi hdi ca chd phin hdi cda bg didu khidn vdng kin Videfridttieu dao dgng dugc thyc hidn vdi mdt tin hieu tham chidu dugc dy bao dao ddng trudc nd dugc xay han la vide cd ging dieu chinh dua he thdng vd trang thai mong mudn Viec thuc hien theo phuang phap la radt giai phip de dang ban frong vide giam dao dgng so vdi bd didu khidn phin hdi (feedback conttoller) Trong bii bao nay, tic gia gidi thidu cac phuong phap didu khidn vdng hd vide giam dao ddng ddng thdi gidi thidu vide ap dung vao mdt he thdng cu the Bai bao dugcfrinhbaiy nhu sau: phan gidi thidu trinh bay vd dao ddng va y tudng vd vide Iam giam dao ddng Phin hai la gidi thidu vd phuang phap thay doi tin hieu vao Phin ba trinh bay viec ap dung phuang phap thay ddi tin hieu vao cho he ca hgc dang minh vi cac ket qua Cudi ciing la ket luin vi dd xuat PHU'CfNG PHAP THAY DOIHiNH D ^ G TIN HIEU VAO Xet he thong dao ddng bac hai cd ham truyen nhu sau: H{s) X{s) ^ ml , (1) F(S) s~+2^ai„s + Q)l X(s) (2) sma^t frong do, 0)^ =a}„4\-C 2.1 Zero Vibration (ZV) ZV la phuang phap xd Iy ldnh didu khidn nham triet tieu moment quan tinh chi tidt chuyen ddng tao dao dgng tihu phuang tnnh (2) (thanh phin smm^t) Bing each tao moment quin tinh thu cap cd chidu ngugc Iai so vdi moment quan tinh so cip, chung se triet tidu Iin nhau.Khi dd chi tidt se chuydn dgng ma kbdng cdn dao ddng Nhung ndu chi tidt dang chuydn ddng dn dinh rdi diing dot nggt, moment quin tinh lai phit sinh lam chi tidt bi dao dgng Vi thd dimg chuydn ddng vin cin tao moment quan tinh thd cip nhim triet tidu moment quan tinh sa cap Hinh I md ta dip ung dao dgng cua he bac hai (I) dudi tac dgng cda lyc so cap va thd cip Hinh md ti dao ddog cdn Iai dudi tie ddng cda hai xung tac ddng.Bidn va thdi gian tac dgng cda Iuc sa cap va thd cap phy thugc vio dac tinh cda he dao ddng Dao dgng cdn Iai cua he thdng sau bi tic ddng mdt chuoi cac xung Iuc dugc xac dinh nhu sau (Singhose et al., 2000; Sorensen & Singhose, 2008; Sorensen et al., 2007; Sung & Singhose, 2009): V(a>„,^)=4c\ay„,t2 = I'd Viec chuSn hoa bien cac xung tac d6ng dugc rang buoc bdi diSu kien sau: & (7) 1=1 Hinh 2: S i p dng dao d^ng cua ca hai dau v£to Vi vay, phuong trinh (4) dugc viet lai: = (l-4,) + e ' ^ ' ' i ^ =>4,= ^r— (8) 1+ e ^/i^ DjtiC = e j ^ "-^-'^ , do: Hinh 3; Hinh d^ng dSu vao ciia k5^ thu^t ZV [;]= • 1+X K 1+X '2 (9) Trong thuc td, he thdng khdng the thyc hidn vide giam dao dpng bing each tic ddng cac xung lidn tiep Vi vay, tin hidu vio se dugc ph6i hgp vdi cac xung nhip &h dam bao ring dao dgng lai se dugc friet tieu Vide phoi hgp giira tin hidu xung v i tin hieu budc dau vao dugc md t i frong Hinh Tin hidu budc se dugc thay ddi (convolute) bdi cic tin hieu xung rdi dua vao he thdng 2.2 Zero Vibration & Derivative (ZVD) ZV la phuang phap didu khien dao dgng don gian, chinh xac cao Tuy nhidn, phuong phap ZV kha nhay vdi sai sd md hinh, ndu tin so dao ddng rieng cua he thay ddi so vdi gia fri thiel ke, chi tidt se dao ddng trd Iai A_ t T 't Tiiue 0 tj I fjTmie Hinh 4: Hinh dang dan vao cua kj thu?t ZVD voi bien tang nhanh Vi th6 phuong phip ZVD dugc dua nham lam giam d6 nhay sai s6 so vai ZV Phuong phap ZVD dua thSm mgt rang buoc vao phuomg trinh (3), dY{m„,0 dco„ (10) Ti^ chi Khoa hgc Trudng Dgi hgc Cdn Tha Phdn A: Khoa hoc Ty nhien, Cong nghe vd Moi irirdng: 26 (20l3):53-60 Khi dd, phuang phap ZVD cin nhip dd triet tidu moment quin tinh, dua chi tiet vd trang thai chuydn ddng dn dinh Trong hinh 5, gia su tan sd dao ddng ridng cua chi tidt bi sai biet so vdi tan sd dugc tiiidt ke frong he thdng didu khidn (gip 1,1 lin) Vdi ZV, dao dgng se xay vdi bien khoang 15% so vdi khdng ap dung Iq? thuat dieu khidn dao ddng Cdn vdi ZVD, bidn dd dao ddng chi khoang 3% Rd rang ZVD lam cho dao ddng it nhay cim han vdi sai sd md hinh Zero Vibration & Double/Triple Derivative (ZVDD/ZVDDD/ ) Cd the lam giam nhay ssi sd md hinh thap ban nda so vdi ZVD Bing each dua nhip vdi bidn do, thdi didm thich hop dd tang toe din, dua chi tidt vao trang thai dn dinh, phuang phap ZVDD se gidp dao ddng dugc kiem soat tdt han Ndu cin thidt, nhip thd co thd dua vao md hinh didu khidn (ZVDDD) nham lam giam ban nua nhay dao ddng vdi sai sd md hinh, xem hinh Noraializerd Fre(piency(e) / „) 6: Dudng d§c tinh vl nh^y sai s6 cua ZV, ZVD, ZVDD & ZVDDD Cd thd thay, ZV, ZVD, ZVDD, ZVDDD deu Iam giam tdc tang tdc cua chuydn dgng Tang tdc timg budc, dao dgng se dugc kiem soat tdt han Vi the, cd the dung phuang phap tang tdc tdng budc vdi bidn dd mdi budc nhd, tang dan ddn t « ; cyc dai Khi dd dao dgng se giam dang kd va nhay vdi sai so md hinh rat thip so vdi cac phuang phap khac Cd the dung PWM de thyc hidn didu 2.4 Unity Magnitude (UM) UM la mgt phuang phip dieu khidn dao dgng Trong bien cua cac nhip ddu bing nhau, xem hinh (Sirri, 2011) Phuang phap thich hgp vdi cic he thdng didu khidn dan giin Bang cich bd fri chieu cua nhip dng vdi thdi diem thich hgp cd thd Iridt tidu moment quan tinh ciia chi tiet chuyen ddng Do bien xung tic ddng ludn la va tdng bidn cic xung phai thoi man phuang frinh (7) nen sd lugng xung nhip khdi ddng cung nhu ddng ludn la mgt sd le Thdi didm dat xung nhip dugc xic dinh bang cich giao dd thi xung tam giic vdi thi dao ddng hinh sine cd tan so Ii tan sd dao ddng ridng cda hd thdng, nghiem cda nd se la thdi diem de dat cac nhip vao Tin sd xung tam giac dugc thay ddi ngau nhien (thdng thudng se chgn moc l i !4 T^^ va giam din dd cd it nhat la xung nhip), sau dd tinh toan xem V{&„,^) cd nhd nhit chua, neu chua thi didu chinh tin sd xung tam giic (tang tin sd) va tidp tuc tinh K ( O „ , ^ ) ddn cd V{m„,C} la be nhit Khi giao dd thi xung tam giac vdi dd thi dao dgng hinh sine cda tin sd dao dgng ridng, nghidm cda nd se la thdi didm de dat cic nhip vio Ngoai cung cd thd thay ddi bidn cua xung sine va giao vdi xung tam giac nhu phuang phap trdn de tim gia tri nhd nhit cda V\o}„,Q Phuang phap dieu chd xung UM dugc frmh bay nhu hinh 8I I Vdi phuang phap UM, thdi gian thyc hien chi nda chu ky dao dgng ridng cda chi tidt, vi the UM giup friet tieu dao dgng nhanh han so vdi cac phuang phap ZV Bu lai, UM nhay vdi sai sd md hinh ban phuong phap ZV, xem Hinh 12 Tap chi Khoa hoc Tmdng Bai hoc Can Tha Phdn A Khoa hoc Tv nhien, Cong nghe vd Moi trirang: 26 (2013):53 btp^-Stt^Etaijii^i^^ij^Sai^H^^ j/u:.- 'L,'^l 44 i, t L y \! V- Reference SIIIIH! CamerwBve Shaped inpul " nr Tô.l" ằ"^,*f>'^ Hinh 10 UMvdiTubip 'I r J ãã, '• - V Hinh 7: Phuong phip diin chC UM(Sirn, 2011) \ InpnTsh^iiiij far Biree.Twhe Aafa A Reference sipinl J -"-, -, V- \ -V \ — Shaped infiui [ TniK(i) • • - - Hinh 11 UMv(n9nhip /" —— SliQpcd lopur 003 0.1 Hinh UM vol nhip k'i r ' N 92 0^4 0.68 0.98 1.0: Normalized Frequency