B CNG THNGTRNG I HC CNG NGHIP TP. HCMKHOA CNG NGH IN T

N HC PHN 2B

IU KHIN TC NG C DC DNG CARD PCI / USB 6221TRN C S PHN MM LABVIEW

Ging vin hng dn : Th.s Nguyn Ngc SnSinh vin thc hin: MSSV:ng Xun Ton 10062211H Vit t10251791Lp : HT6AKho : 2010 -2014Email: Xuantoan287@gmail.com

n Hc Phn 2BGVHD: Th.s Nguyn Ngc SnTP. H Ch Minh, thng 12 nm 201320

B CNG THNGTRNG I HC CNG NGHIP TP. HCMKHOA CNG NGH IN T

N HC PHN 2B

IU KHIN TC NG C DC DNG CARD PCI 6221TRN C S PHN MM LABVIEW

Ging vin hng dn : Th.s Nguyn Ngc SnSinh vin thc hin: MSSV:ng Xun Ton 10062211H Vit t10251791Lp : HT6AKho : 2010 -2014

n Hc Phn 2BGVHD: Th.s Nguyn Ngc SnTP. H Ch Minh, thng 12 nm 201353

LI M U

Trong qu trnh cng nghip ha- hin i ha t nc. T ng ha l yu t khng th thiu trong mt nn cng nghip hin i. Ni n t ng ha th my tnh l mt cng c h tr c lc nht v khng th thiu c trong rt nhiu lnh vc, c bit trong o lng v iu khin.Vic ng dng my tnh vo k thut o lng v iu khin em li nhiu kt qu y tnh u vit. Cc thit b, h thng o lng v iu khin ghp ni vi my tnh c chnh xc cao, thi gian thu thp d liu ngn. Nhng iu ng quan tm nht l mc t ng ha trong vic thu thp v x l kt qu o, k c vic lp bng thng k, ha, cng nh in ra kt qu. o lng v iu khin h thng th ngoi cc thit b ghp ni vi my tnh, cn c Smt chng trnh np vo my tnh x l v iu khin qu trnh hot ng ca h thng.Vic ng dng my tnh vo trong cc h thng truyn ng iu khin tc , v tr ngy cng ph bin. V d nh trong cc dy truyn lp rp cc sn phm k thut cao, trong vic gia cng sn phm c hnh dng, kch thc c v trc trn my tnh, trong c cu truyn ng cho tay my, ngi my, c cu n dao my ct gt kim loi quay anten, knh vin vng, trong cc h thng bm, ty ng,LabVIEW l mt ngn ng lp trnh chuyn nghip trong lnh vc t ng ha, l mt mi trng lp trnh cho php to ra cc chng trnh s dng k hiu ha gip to ln nhng giao din chng trnh chuyn nghip. N cha ng rt nhiu kh nng, sc mnh khi pht trin v thc thi cc ng dng t ng ha: o lng, thu thp, phn tch, x l d liu... Th gii thit b o ca labVIEW rt gn gi v lin kt cht ch vi th gii iu khin t ng thc.

LI CM N

u tin chng em xin chn thnh gi li cm n n nh trng v cc thy c trong khoa in t tn tnh dy d v du dt chng em trong sut thi gian hc va qua, chng em c kin thc chuyn mn, chng em c th lm vic v gip ch cho x hi. thc hin thnh cng n ny em xin chn thnh cm n s hng dn, ch o tn tnh ca thy Nguyn Ngc Sn, thy hng dn tn tnh gip chng em nh hng, gp v cung cp tng cng nh ch dn v ti liu v cc tin trnh thc hin n. S hng dn ca thy l yu t quan trng chng em c th hon thnh ti c giao.Cui cng em xin gi li cm n tt c bn b gip v ng vin trong sut qu trnh lm n. Do kinh nghim v trnh cn hn ch nn phn th hin v trnh by ca chng em cn nhiu khim khuyt.Rt mong c s gip v tham kho kin ca cc Thy c chng em c th pht trin thm ti. Chng em xin chn thnh cm n !

Sinh vin thc hin ng Xun Ton H Vit t

NHN XT(Gio vin hng dn)..........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................NHN XT(Hi ng phn bin)MC LC LI M U: Trang CHNG 1: M U101.1. L do chon ti101.2. Mc ch nghin cu101.3. i tng phm vi nghin cu101.4. Phng php nghin cu101.5. ngha khoa hc v thc tin ca ti10CHNG 2: IU KHIN NG C IN MT CHIU11 2.1. Khi qut v ng c in mt chiu11 2.2. Cu to c bn my in mt chiu11 2.2.1. Cu to11 2.2.2. Nguyn l hot ng13 2.2.3. Phn loi ng c in mt chiu13 2.3. iu KHIN NG C DC14 2.3.1. Khi nim chung14 2.3.2. Cm bin (Encorder)15 2.3.3. Cc phng trnh c bn ca my in mt chiu16 2.3.4. Cc phng php iu khin tc ng c17CHNG 3 THUT TON IU KHIN PID183.1. B iu khin PID tng t.183.2. L thuyt iu khin b iu chnh PID s193.2.1. Khu hiu chnh khuch i t l (P)193.2.2. Khu tch phn I203.2.3. Khu iu khin vi phn D: (hot ng do hm)213.2.4. Khu tch phn t l (PI)213.2.5. Khu PID213.3. Cc phng php thit k b iu chnh PID233.3.1. Phng php Ziegler-chols233.3.2. Phng php Chien-Hrones-Reswick25CHNG 4 Lp trnh trong mi trng labview264.1. Khi qut chung v phn mm labview264.1.1. Gii thiu v LABVIEW264.1.2. Cc chc nng chnh ca LABVIEW264.2. Thit b o (VI- Vitual Instrument)264.2.1. Front panel274.2.2. S khi (Block Diagram)274.3. K THUT LP TRNH LABVIEW284.3.1. Khi ng chng trnh284.3.2. Cng c trn thanh giao din304.3.2.1. Thanh cng c trn front panel304.3.2.2. Thanh cng c trn Block Diagram304.3.3. Cc cng c h tr lp trnh314.3.3.1. Tool Panel314.3.3.2. Bng iu khin (Controls Palette)324.3.3.3. Bng chc nng Functions Palette324.3.4. Cc khi lp trnh thng dng33CHNG 5 GII THIU V CARD PCI 6221375.1. Tng quan v card PCI 6221375.2. S ni chn385.3. Thng s k thut395.3.1. u vo tng t395.3.2. u ra tng t405.3.3. K thut s I/O415.3.4. Lp trnh thi gian / B m415.3.5. I/O kt ni m t tn hiu41CHNG 6 Thit K Phn Cng V Giao Din iu Khin436.1. Phng n Thit K 436.1.1. Yu cu thit k436.1.2. Thit k436.1.3. Modul Driver L298436.1.4. Phng php iu khin446.2. Giao din iu khin bng my tnh446.2.1. Front Panel v Block diagram ca chng trnh456.2.1.1. Kt ni Dac c gi tr encoder456.2.1.2. Kt ni u ra xut xung PWM Analog Output466.2.1.3. Khu hiu chnh PID486.2.1.4. To nt tt dng486.3. Giao din v chng trnh496.3.1. Giao din chnh Front Panel496.3.2. Chng trnh Block Diagram506.3.3. Kt qu t c50KT LUNTI LIU THAM KHOMC LC HNH NHHnh nhtrang

Hnh 1. ng c Servo11

Hnh 2 : Mt ct ngang my in mt chiu12

Hnh 3: Cc thnh phn ca ng c DC Servo12

Hnh 4: S nguyn l lm vic ca ng c in mt chiu13

Hnh 5: Cc loi ng c in mt chiu14

Hnh 6 : Nguyn l m ca Encoder.15

Hnh 7 : Hnh dng a encoder15

Hnh 8 : xung u ra ca econder16

Hnh 9:Cu trc b iu khin PID18

Hnh 10 : S b iu khin PID s22

Hnh 11: Chng bo ha tch phn23

Hnh 12: p ng nc ca h h c dng S23

Hnh 13 : p ng nc ca h kn khi k = kth24

Hnh 14: p ng nc ca h thch hp cho phng php Chien-Hrones-Reswick25

Hnh 15 : Giao din front panel27

Hnh 16 : Giao din ca s khi.28

Hnh 17: Thanh cng c giao din front panel30

Hnh 18: Thanh cng c giao din Block Diagram30

Hnh 19: Bng iu khin (Controls Palette)32

Hnh 20: Bng chc nng Functions PaletteHnh 21: Cc k hiu trong ton hc33

Hnh 22: Cc ton t so snh34

Hnh 23: Khi PID34

Hnh 24: Khi biu din th35

Hnh 25: Cc hm35

Hnh 26: Cc bin36

Hnh 27: Khi kt ni Ni DAQ I/O36

Hnh 28: Card PCI 622137

Hnh 29: S ni chn 38

Hnh 30 : S Modul Driver L29843

Hnh 31: Giao din chnh Front Panel 49

Hnh 32: Chng trnh Block Diagram50

Hnh 33: Kt qu t c50

Hnh 34: M hnh thc nghim 151

Hnh 35: M hnh thc nghim 252

CHNG 1M U1.1. L DO CHON TINgy nay,vi s pht trin nhanh chng ca nn kinh t i hi s tng trng tng ng trong h tng c s k thut.V nhim v ca ngi k s l tm v x l cc bi ton t ra trong qu trnh tnh ton ,ng thi gim st v c th a ra hnh nh m phng c th. Mt trong nhng bi ton kh l iu khin chnh xc v tr ca mt i tng c th nh ng c,c cu trc Vt-me,..V cng c rt mnh c th x l,m phng bi ton trn l LabVIEW.1.2. MC CH NGHIN CU CA NTrong phm vi nghin cu ca n chng em ch yu nghin cu v cch thc s dng phn mm Labview c bn nh: cch to giao din , lp trnh s khi , to thit b o (VI) v thit b con Sub VI, ..Nghin cu card PCI 6221 t kt hp vi Labview to ra mt ng dng c th trong o lng v iu khin.1.3. I TNG PHM VI NGHIN CUi tng nghin cu chung ca n l: Phn mm Labview Carb PCI 6221Phm vi nghin cu:Do phm vi nghin cu ngn nn chng em ch tp trung nghin cu mt ng dng quen thuc ca Labview v card PCI 6221. l iu khin tc ng c DC dng card PCI 6221 trn c s phn mm Labview. 1.4. PHNG PHP NGHIN CU. thc hin nghin cu ti khoa hc ny, chng em kt hp 3 phng php sau:- Phng php nghin cu l thuyt: Nghin cu cc vn v ng dng iu khin PID s, cc m hnh ng c in mt chiu, iu khin v gim sat trn nn phn mm Labview.- Phng php m phng: S dng cng c tnh ton v m phng trong phn mm Labview, to d liu m phng v nhn dng m hnh thc nghim ng c.- Phng php thc nghim: Thit k mch phn cng iu khin,h thng gim st. 1.5. NGHA KHOA HC V THC TIN CA TKt qu nghin cu ca ti s gp phn hon thin mt phng php iu khin mi khc phc c mt s nhc im ca cc phng php K tng t.CHNG 2:IU KHIN NG C IN MT CHIU

2.1. KHI QUT V NG C IN MT CHIUHin nay ng c in mt chiu vn c dng rt ph bin trong cc h thng truyn ng in cht lng cao, di cng sut ng c mt chiu t vi W n hng MW. y l loi ng c a dng v linh hot, c th p ng yu cu mmen, tng tc, v hm vi ti trng nng. ng c in mt chiu cng d dng p ng vi cc truyn ng trong khong iu khin tc rng v o chiu nhanh vi nhiu c tuyn quan h mmen tc .Trong ng c in mt chiu, b bin i in chnh l cc mch chnh lu iu khin. Chnh lu c dng lm ngun iu chnh in p phn ng ng c. Chnh lu y s dng chnh lu cu 3 pha.2.2. CU TO C BN MY IN MT CHIU 2.2.1. Cu to

Hnh 1. ng c Servo

Ging nh cc loi ng c in khc, ng c in mt chiu cng gm c stator v rotor.ng c in mt chiu gm c stator, rotor, c gp v chi in

Hnh 2 : mt ct ngang my in mt chiu

Hnh 3 Cc thnh phn ca ng c DC ServoStator: cn gi l phn cm, gm dy qun kch thch c qun tp trung trn cc cc t stator. Cc cc t stator c ghp cch in t cc l thp k thut in c dp nh hnh sn c b dy 0,5-1mm, v c gn trn gng t bng thp c, cng chnh l v my.Rotor: cn c gi l phn ng, gm li thp phn ng v dy qun phn ng. li thp phn ng c hnh tr, c ghp t cc l thp k thut in ghp cch in vi nhau. Dy qun phn ng gm nhiu phn t, c t vo cc rnh trn li thp rotor. Cc phn t dy qun rotor c ni tip nhau thng qua cc l gp trn c gp. Li thp phn ng v c gp c c nh trn trc rotor.C gp v chi in: lm nhim v o chiu dng in trong dy qun phn ng.

2.2.2. Nguyn l hot ng

Hnh 4: S nguyn l lm vic ca ng c in mt chiuMt khung dy abcd hai u ni vi 2 phin gp, t trong t trng ca mt nam chm vnh cu N-S, hai chi in A v B t c nh v t st ln trn 2 phin gp.t in p mt chiu U vo hai chi than A, B. Khi trong dy qun phn ng s sinh ra dng in I. Cc thanh dn ab, cd c dng in chy qua, li c t trong t trng ca nam chm vnh cu li chu tc dng ca lc Ft tc dng lm cho roto quay. Chiu quay ca roto cng chiu vi lc in t c xc nh theo quy tc bn tay tri.Khi phn ng quay c na vng th v tr cc thanh dn ab, cd i ch cho nhau o cc phin gp i chiu dng in gi cho chiu ca lc tc dng khng i m bo ng c c chiu quay khng i.Khi t ln dy qun kch t mt in p kch t Uk no th trong dy qun kch t s xut hin dng kch t ik v do mch t ca my s c t thng . Tip t mt gi tr in p U ln mch phn ng th trong dy qun phn ng s c mt dng in I chy qua. Tng tc gia ng in phn ng v t thng kch thch to thnh mmen in t. Gi tr mmen in t c tnh nh sau:Trong cc p: s i cp cc ca ng c.n: s thanh n phn ng di mt cc t.a: s mch nhnh song song ca dy qun phn ng.k: h s kt cu ca my.V mmen in t ny ko cho phn ng quay quanh trc.

2.2.3. Phn loi ng c in mt chiuDa vo hnh thc kch t, ngi ta chia ng c in mt chiu thnh cc loi sau:ng c in mt chiu kch t c lp: Dng in kch t c ly t ngun ring bit so vi phn ng. Trng hp c bit, khi t thng kch t c to ra bng nam chm vnh cu, ngi ta gi l ng c in mt chiu kch thch vnh cu.ng c in mt chiu kch t song song: Dy qun kch t c ni song song vi mch phn ng.ng c in mt chiu kch t ni tip: Dy qun kch t c mc ni tip vi mch phn ng.ng c in mt chiu kch t hn hp: Dy qun kch t c hai cun, dy qun kch t song song v dy qun kch t ni tip. Trong , cun kch t song song thng l cun ch o. Hnh 1.3 trnh by cc loi ng c in mt chiu

Hnh 5: Cc loi ng c in mt chiua) ng c in mt chiu kch t c lpb) ng c in mt chiu kch t song song c) ng c in mt chiu kch t ni tipd) ng c in mt chiu kch t hn hp2.3. IU KHIN NG C DC2.3.1. Khi nim chungiu khin tc l mt yu cu: cn thit tt yu ca cc my sn xut. Ta bit rng hu ht cc my sn xut i hi c nhiu tc , ty theo tng cng vic, iu kin lm vic m ta la chn cc tc khc nhau ti u ha qu trnh sn xut. Mun c c cc tc khc nhau trn my ta c th thay i cu trc ca my nh t s truyn hoc thay i tc ca chnh dng c truyn ng.Tc lm vic ca ng c do ngi iu khin quy nh c gi l tc t. Trong qu trnh lm vic, tc ca ng c c th b thay i v tc ca ng c ph thuc rt nhiu vo cc thong s ngun, mch v ti nn khi cc thng s thay i th tc ng c s b thay i theo. Tnh trng gy ra sai s v tc v c th khng cho php. khc phc ngi ta dng nhng phng php n nh tc . n nh tc cn nh hng quan trng gii iu chnh (phm vi iu chnh tc ) v kh nng qu ti ca ng c. n nh cng cao th kh nng m rng v mmen qu ti cng ln.C rt nhiu phng php iu chnh tc ng c nh:iu chnh tham s.iu chnh in p ngun.iu chnh cu trc s .

2.3.2. Cm bin (ENCODER) :Phng php o tc ng c thng dng nht hin nay dng cm bin quang hay cn gi l encoder. Tn hiu t encoder to ra cc dng xung vung c tn s thay i vo tc ng c. Do cc xung vung ny c a vo b vi x l m s xung trong khong thi gian cho php t ta c th tnh c gi tr vn tc ca ng c. y cng l phng php m ngi ta s dng n nh tc ng c hay iu khin nhanh chm....

Hnh 6 : Nguyn l m ca Encoder.Nguyn l c bn ca encoder, l mt a trn xoay, quay quanh trc. Trn a c cc l (rnh). Ngi ta dng mt n led chiu ln mt a. Khi a quay, ch khng c l (rnh), n led khng chiu xuyn qua c, ch c l (rnh), n led s chiu xuyn qua.Khi , pha mt bn kia ca a, ngi ta t mt con mt thu. Vi cc tn hiu c, hoc khng c nh sng chiu qua, ngi ta ghi nhn c n led c chiu qua l hay khng. Nh vy l encoder s to ra cc tn hiu xung vung v cc tn hiu xung vung ny c ct t nh sng xuyn qua l. Nn tn s ca xung u ra s ph thuc vo tc quay ca tm trn . i vi encoder mnh ang dng th n c 2 tn hiu ra lch pha nhau 90. Hai tn hiu ny c th xc nh c chiu quay ca ng c.

Hnh 7 : Hnh dng a encoderHai xung a ra lch nhau mt gc 90 nu vng ngoi nhanh pha hn vng trong th ng c quay t tri sang phi v ngc li

Hnh 8 : xung u ra ca econder2.3.3. Cc phng trnh c bn ca my in mt chiu:Sut in ng phn ng E=K (1)in p phn ng U= E+RI (2)Mmen phn ng M= K (3)Trong : U: in p ca li in mt chiu E: sut in ng cm ng trong cun dy rotor khi n quay trong t trng do cun dy kch t to ra. : t thng trn mi cc (Wb) I: dng phn ng (A) U: in p phn ng (V) R: in tr phn ng () : tc ng c(rad/s) : mmen phn ng ca ng c (Nm) : hng s, ph thuc cu trc ng cT cng thc (1) v (3), ta c: (4)Hay (5)Vi ng c mt chiu kch t c lp, nu in p kch t c duy tr khng i, c th gi thit rng t thng ng c khng i khi mmen ng c thay i.Khi ta c: K=constant (6)Nh vy c tnh ca ng c mt chiu kch t c lp l mt ng thng. Tc khng ti ca ng c xc nh bi in p cung cp U v t thng kch t K. Tc ng c gim khi mmen ti tng v n nh tc ph thuc vo in tr phn ng R. Trong thc t do phn ng phn ng, t thng gim do mmen tng dn n tc ng c suy gim t hn l tnh ton theo cng thc trn. Vi mmen ln t thng c th suy gim n mc dc c tnh c tr nn dng dn n hot ng khng n nh. V vy, cun b thng hay c s dng lm gim hiu ng kh t ca phn ng phn ng. Vi ng c cng sut trung bnh, st tc khi ti nh mc so vi khi khng ti khong 50%.Vi ng c mt chiu kch t ni tip, t thng l mt hm ca dng phn ng. Nu gi thit ng c hot dng trong vng tuyn tnh ca c tnh t ha, c th xem t thng t l bc nht vi dng phn ng, ngha l:=KktI (7)Thay (7) vo (1), (4) vo (5) ta c:M= KKktI2 (8) (9) (10)R lc ny l tng ca in tr mch phn ng v in tr phn kch t.c tnh ca ng c mt chiu kch t ni tip c v nh hnh trn . C th thy rng tc ca ng c suy gim nhiu theo mmen ti. Tuy nhin trong thc t, cc ng c tiu chun thng c thit k lm vic ti cc cnh ch (Kn-point) ca c tnh t ha khi mang ti nh mc. Vi ti trn nh mc, mch t ng c bo ha, khi t thng khng thay i nhiu theo dng ti dn n c tnh c tim cn vi ng thng.ng c mt chiu kch t ni tip thch hp cho cc ng dng i hi momen khi ng cao v c th qu ti nng. Vi momen ti nng, t thng ng c cng tng theo. 2.3.4. Cc phng php iu khin tc ng cT cc phng trnh trn ta biu din quan h gia tc - momen, in p, dng phn ng, t thng v in tr. Ta c th thy rng tc ng c c th c iu khin bng cc phng php sau:1. iu chnh in p phn ng.2. iu chnh t thng.3. iu chnh in tr phn ng.4. Phng Php iu khin rng xung PWM.V phng din iu chnh tc , ng c in mt chiu c nhiu u vit hn so vi loi ng c khc, khng nhng c kh nng iu chnh tc d dng m cu trc mch lc, mch iu khin dn gin hn ng thi t cht lng iu chnh cao trong di iu chnh tc rng. Trong thc t c hai phng php c bn iu chnh tc ng c in mt chiu: iu chnh in p cp cho phn ng ng c. iu chnh in p cp cho mch kch t ng c.Trong cc phng php trn : Phng Php iu khin rng xung PWM c s dng l thch hp nht.

CHNG 3 THUT TON IU KHIN PIDMt vn iu khin c th c nhiu c im khc nhau nh n nh ca vng kn v vng h, loi b c nhiu lon bc, thi gian thit lp, nh vt l, thi gian xc lp, dc suy gim .Chng em nhn thy rng PID c l l thit k iu khin hi tip c s dng nhiu nht, n m bo c nhng iu kin cn thit khi iu chnh ng c nh ni trn. Cc b iu khin PID l lp thit lp tt nht trong h thng iu khin, hn na cng vi kin thc c hc trong nh trng m nim mong mun tm hiu k hn v b iu khin PID , do yu cu ca ti nn chng em quyt nh chn b iu khin PID iu khin cho ng c DC ca mnh.3.1. B IU KHIN PID TNG T PID l cch vit tt ca cc t Propotional (t l), Integral (tch phn) v Derivative (o hm). Tuy xut hin rt lu nhng n nay PID vn l gii thut iu khin c dng nhiu nht trong cc ng dng iu khin t ng. B iu khin PID c s dng rng ri trong thc t iu khin cc i tng khc nhau nh nhit l nhit, tc ng c, mc cht lng trong bn chaL do b iu khin ny c s dng rng ri l v n c kh nng trit tiu sai s xc lp, tng p ng qu , gim vt l nu cc tham s b iu khin c chn la thch hp. Do s thng dng ca n nn nhiu hng sn xut thit b iu khin cho ra i cc b iu khin thng mi rt thng dng. PID l b iu khin hon ho gm ba tnh cht sau: Phc tng v thc hin chnh xc nhim v c giao (t l P). Lm vic c tch ly kinh nghim thc hin tt nhim v (tch phn I). Lun c sang kin v phn ng nhanh nhy vi s thay i tnh hung trong qu trnh thc hin nhim v (vi phn D). Cu trc ca b iu khin PID (hnh 2.1) gm c ba thnh phn l khu khuch i (P), khu tch phn (I) v khu vi phn (D).Khi s dng thut ton PID nht thit phi la chn ch lm vic l P, I hay D v sau n l t tham s cho cc ch chn,c ba thut ton c bn c s dng l P,PI v PID.

Hnh 9: Cu trc b iu khin PIDB PID c nhim v a sai lch e(t) ca h thng v 0 sao cho qu trnh qu tha mn cc yu cu c bn v cht lng:- Nu sai lch tnh e(t) cng ln th thng qua thnh phn uP(t), tn hiu iu chnh u(t) cng ln.- Nu sai lch e(t) cha bng 0 th thng qua thnh phn uI(t), PID vn cn to tn hiu iu chnh.

B iu khin PID c m t bng m hnh vo-ra:

Trong : = h s t l = hng s thi gian tch phn = hng s thi gian vi phn3.2. L THUYT IU KHIN B IU CHNH PID SLut PID trn min thi gian (lin tc) c m t bi cng thc:

Trong : = h s t l = hng s thi gian tch phn = hng s thi gian vi phn3.2.1. Khu hiu chnh khuch i t l (P)c a vo h thng nhm lm gim sai s xc lp, vi u vo thay i theo hm nc s gy vt l cao do v tr s khng ng theo yu cu.Tn hiu ra ca b iu khin c dng:U(t)=Kp.e(t)Ngha l tn hiu ra ch n gin l tch ca h s sai lch gia tn hiu t v tn hiu thc. Sai lch tnh: i vi quy lut iu chnh P, khi tc ng c bng vi tc t e=0 th tn hiu iu khin cng bng 0 v do tc ng c s b ko gim xung. V vy mun u 0 th e phi khc 0. Ngha l phi lun c mt sai lch gia tn hiu t v tn hiu u ra thc t ca tn hiu iu khin. Gim sai lch tnh: nu tng ln sai lch tnh c th to ra mt tn hiu duy tr mt momen ln gi cho ng c quay. R rng tng th c th gim c sai lch tnh. Tuy nhin, nu tng qu ln th c th b dao ng khng n nh.3.2.2. Khu tch phn Iiu khin hot ng I: lch tng bi s quan h gia v tr t ca h iu khin v v tr hin ti, v gi sau khi h thng iu khin t trng thi bn. S lch ny gi l sai s. Nu nh sai s xy ra trong b iu khin m ch thc hin iu khin t l, th n s thiu chnh xc. Gim v loi sai s v tr iu khin hp vi im t. Khu P thng c dng kt hp vi b iu khin tch phn I.

Bn cht l php tnh xp x din tch ca hm e(t) Xp x theo nguyn tc hnh ch nht:

Xp x theo nguyn tc hnh thang:

Trong : T l chu k trch mu

3.2.3. Khu iu khin vi phn D: (hot ng do hm)c i hi phi b, c thc hin ng vi bin t t l, mc nghing ca lch: Khai trin thnh chui:

Vi phn xp x bc 2:) ) Vi phn xp x bc 1:

3.2.4. Khu tch phn t l (PI)Khin h tr thnh v sai. Mun tng chnh xc ca h thng ta phi tng h s khuch i. Song i vi h thng thc b hn ch th s c mt ca khu PI l bt buc.3.2.5. Khu PID`Cc b hiu chnh PID c ng dng nhiu di dng thit k iu khin hay thut ton hiu chnh bng phn mm. Nu tn hiu u vo l sai s e(t), tn hiu u ra l iu khin in p u(t) th: (1)Ta c hm truyn t ca khu hiu chnh PID: (2)Hoc dng khc: (3)Theo nguyn tc tch phn hnh thang th: (4)Cn phn o hm th: (5)Nh vy: (6)Thay i ch s t K thnh (K-1) v tr hai v ca phng trnh ta c: (7)Nu cc t cc h s: (8) (9) (10)Th: (11)M hnh b iu khin PID s:

Hnh 10 : S b iu khin PID sMt vn quan trng cn quan tm thit k b iu khin PID l vic hn ch cc hin tng bo ha tch phn (Winup).Vn ny rt thng gp khi thc thi lut iu khin PID. Hin tng bo ha tch phn l hin tng u ra ca b iu khin vn tip tc tng qu mc gii hn do tch ly ca thnh phn tch phn vn cn khi sai lch iu khin tr v 0. Gii quyt vn 4 phng php: Khi sai lch m hnh bng 0, ta thc hin tch b thnh phn tch phn hoc xa trng thi ca n bng vng lp. Gim h s khuch i u ra nm trong gii cho php khng qu ln. Thc hin thut ton b tch phn bng phn hi gi tr thc o c. t mt khu gii hn u ra ca b iu khin v s dng thut ton b. Hai phng php cui c u im hn c v thng c hu ht cc b iu khin cng nghip h tr. Gii php a nng v p dng nhiu trn thc t thc hin Anti_winup l iu khin bm (tracking) thc cht ci thin thnh phn tch phn I:

Hnh 11: Chng bo ha tch phn3.3. Cc phng php thit k b iu chnh PID 3.3.1. Phng php Ziegler-cholsPhng php Ziegler-Nichols l php thc nghim xc nh tham s b iu khin P, PI, hoc PID bng cch d vo p ng qu ca i tng iu khin. Ty theo c im ca tng i tng, Ziegler v Nichols a ra hai phng php la chn tham s ca b iu khin:Phng php Ziegler-Nichols th nht: Phng php ny p dng cho cc i tng c p ng i vi tn hiu vo l hm nc c dng ch S (hnh 2.4) nh nhit l nhit, tc ng c

Hnh 12: p ng nc ca h h c dng S

Thng s ca cc b iu khin c chn theo bng sau:Bng 2.1: Cc tham s PID theo phng php Ziegler-Nichols th nhtThng sBKKpTITD

PT2/(k.T1)--

PI0,9T2/(k.T1)T1/0,3-

PID1,2T2/(k.T1)2T10,5T1

Phng php Ziegler-Nichols th hai: Phng php ny p dng cho i tng c khu tch phn l tng nh mc cht lng trong bn cha, v tr h truyn ng dng ng c p ng qu ca h h ca i tng tng n v cng. Phng php ny c thc hin nh sau [4]:

- Thay b iu khin PID trong h kn bng b khuch i (hnh 2.4).- Tng h s khuch i ti gi tr ti hn kth h kn ch bin gii n nh, tc l h(t) c dng dao ng iu ha.- Xc nh chu k Tth ca dao ng.

Hnh 13 : p ng nc ca h kn khi k = kthThng s ca cc b iu khin c chn theo bng sau:

Bng 2.2: Cc tham s PID theo phng php Ziegler-Nichols th 2Thng sBKKpTITD

P0,5kth--

PI0,45kth0,85Tth-

PID0,6kth0,5Tth0,125Tth

2.3.2. Phng php Chien-Hrones-ReswickPhng php ny cng p dng cho cc i tng c p ng i vi tn hiu vo l hm nc c dng ch S (hnh 2.6) nhng c thm iu kin: b/a>3*Cch tnh Kp, Ti, Td:Nhn chung i vi vic iu khin v tr ng c DC, th ngoi phng php kh sai ra hu nh khng cn phng php no khc xc nh thng s PID.Ngha l ta chn mt gi tr no ca cc thng s v cho h thng chy th, thay i cc thng s ny theo chiu hng h n nh v t cht lng nh mong mun, n khi no ta chn c cc thng s ti u th vic chn cc thng s PID chm dt. Tuy nhin, d qu trnh chn thng s PID tr nn n gin ta dng phng php Ziegler-Nichol tnh thng s PID t hm truyn ca ng c, v ly cc thng s ny th h thng, thay i vi ln cc gi tr gn vi thng s ny ta s c h thng ti u.L do cc gi tr tm c t phng php Ziegler-Nichol khng phi l cc ti u, l do phng php Ziegler-Nichol ch p dng cho h thng c qun tnh ln, cn ng c DC p ng nhanh.Theo phng php 1 ca nguyn tc hiu chnh Ziegler-Nichol (cho PID):Vi T1,T2 c xc nh t ng c tuyn tc ca ng c:

Hnh 14 : c tnh tc ng cCHNG 4LP TRNH TRONG MI TRNG LABVIEW4.1. KHI QUT CHUNG V PHN MM LABVIEW4.1.1. Gii thiu v LABVIEW LABVIEW (vit tt ca nhm t Laboratory Virtual InstrumentationEngineering Workbench) l mt phn mm my tnh c pht trin bi cngty National Instruments, Hoa k. LABVIEW cn c bit n nh l mt ngnng lp trnh vi khi nim hon ton khc so vi cc ngn ng lp trnh truynthng nh ngn ng C, Pascal. Bng cch din t c php thng qua cc hnhnh trc quan trong mi trng son tho, LABVIEW c gi vi tn khcl lp trnh G (vit tt ca Graphical, ngha l ha). LABVIEW (Virtual Instrument Engineering Workbench) l mt mitrng pht trin da trn ngn ng lp trnh ho, thng c s dng chomc ch o lng, kim tra, nh gi, x l, iu khin cc tham s ca thitb. LABVIEW l mt ngn ng lp trnh a nang, ging nh cc ngn ng lptrnh hin di khc. LABVIEW gm c cc th vin thu nhn d liu, mt lotcc thit b iu khin, phn tch d liu, biu din v lu tr d liu. N cn ccc cng c pht trin c thit k ring cho vic ni ghp v iu khin thitb. LABVIEW khc vi cc ngn ng lp trnh thng thng im c bn l:cc ngn ng lp trnh khc thng dng trn c ch dng lnh, trong khi LABVIEW dng ngn ng lp trnh Graphical d to ra cc chng trnh dng s d khi. 4.1.2. Cc chc nng chnh ca LABVIEW Thu thp tn hiu t cc thit b bn ngoi nh cm bin nhit d, hnh nht webcam, vn tc ca ng c, ... Giao tip vi cc thit b ngoi vi thng qua nhiu chun giao tip thng quacc cng giao tip: RS232, RS485, USB, PCI, Ethernet . M phng v x l cc tn hiu thu nhn c phc v cc mc dchnghin cu hay mc ch ca h thng m ngi lp trnh mong mun. Xy dng cc giao din ngi dng mt cch nhanh chng v thm m hnnhiu so vi cc ngn ng khc nh Visual Basic, Matlab,.. Cho php thc hin cc thut ton diu khin nh PID, Logic m (FuzzyLogic), mt cch nhanh chng thng qua cc chc nng tch hp sn trongLABVIEW. Cho php kt hp vi nhiu ngn ng lp trnh truyn thng nh C, C++, ...4.2. Thit b o (VI- Vitual Instrument):Lp trnh Labview trn c s thit b o. Cc i tng trong thit b o c s dng m phng cc thit b thc, nhng chng c a vo bi phn mm. Cc VI (thit b o) tng t nh cc hm trong cc ngn ng lp trnh khc.4.2.1. Front panel:L giao din ca ngi s dng. V d sau y minh ha front panel.

Hnh 15 : Giao din front panel- Xy dng front panel vi cc b iu khin (controls) v cc hin th(Indicators), chng c s dng vi cc chc nng vo ra d liu. Cc iukhin bao gm cc nm (knobs), nt n (push buttons), mt ng h v cc thitb vo d liu khc. Control l cc i tng c t trn Front Panel cungcp d liu cho chng trnh. N tng t nh u vo cung cp d liu.- Indicator l i tng c t trn Front Panel dng hin th kt qu, n tng t nh b phn u ra ca chng trnh. Cc b hin th l cc th, LED, v cc hin th khc. Cc b iu khin m phng cc tn hiu vo v cung cp d liu cho s khi ca VI cn b hin th m phng cc tn hiu u ra v hin th qu trnh pht hay nhn d liu ra mt my (font panel).4.2.2. S khi (Block Diagram): Block Diagram ca 1 VI l mt s c xy dng trn mi trng Labview, n c th gm nhiu i tng v cc hm khc nhau to cc cu lnh chng trnh thc hin. Block Diagram l mt m ngun ho ca 1 VI. Cc i tng trn Front Panel c th hin bng cc thit b u cui trn Block Diagram, khng th loi b cc thit b u cui trn Block Diagram. Cc thit b u cui ch mt i sau khi loi b i tng tng ng trn Front panel. Block Diagram ca 1 VI n gin c th hin nh hnh di y :

Hnh 16 : Giao din ca s khi.Cu trc ca mt Block Diagram gm cc thit b u cui (Terminal), Nt (Node) v cc dy ni (wire)- Terminal: l cc cng m d liu truyn qua gia Block Diagram v Front panel, v gia cc Node trong Block Diagram. Cc Terminal nm di dng cc Icon ca cc Function - Nodes: l cc phn t thc hin chng trnh, chng tng t nh cc mnh , ton t, hm v cc chng trnh con trong cc ngn ng lp trnh thng thng- Wires: l cc dy ni d liu gia cc node4.3. K THUT LP TRNH LABVIEW4.3.1 Khi ng chng trnhNhp vo biu tng biu tng Labview nh hnh bn. Ta c c giao din bn hnh (a) di.Vo File/New VI vo mi trng lp trnh hnh

+ Front Panel: giao din vi ngi s dng+ Block Diagram: Giao din dng s khi cung cp m ngun4.3.2. Cng c trn thanh giao din4.3.2.1. Thanh cng c trn front panel

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Hnh 17: Thanh cng c giao din front panel Trong :

1. Nt chy chng trnh (thanh khng sng b v: li, phi sa li chng trnh)2. Nt chy lp3. Nt dng cng p chng trnh4. Nt tm dng5. Text setting (mu sc, nh dng, kch thc- phng)6. Ging u i tng theo hng dc v ngang 7. Phn b cc i tng8. Thay i kch thc cc i tng9. Lnh b sung10. Ca s tr gip4.3.2.2. Thanh cng c trn Block Diagram

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16Hnh 18: Thanh cng c giao din Block Diagram

1. Nt chy chng trnh (thanh khng sng b v: li, phi sa li chng trnh)2. Nt chy lp3. Nt dng cng p chng trnh4. Nt tm dng5. Kch vo nt lnh Highlight Execution ta s thy lung d liu chy trongs khi. Khi ta kch li nt lnh ny qu trnh s b dng li.7. Kch vo nt lnh Step into dng d lp tng bc mt trong vng lp, subVI.8. Kch vo nt lnh Step over dng d b qua mt vng lp hoc mt subVI.9. Kch vo nt lnh Step out dng d nhy ra ngoi vng lp hoc subVI. 10. Dng d thit lp font cho VI bao gm kch thc, kiuloi, mu sc. 11. Dng d sp xp cc di tng thng hng nhau bao gm cc ngthng ng, mp trn, tri 12. Dng phn b cc i tng 13. La chn Reorder khi ta c cc i tng gi ln nhau v ta munnh nghia i tng l ng trc hay ng sau. Vic la chn mt trong cci tng vi vic nh v v tr ca n ri sau di chuyn ln pha trc hay di chuyn v pha sau4.3.2. Cc cng c h tr lp trnhVic lp trnh trn Labview cn s dng cc bn: Tools Palette, Controls Panelette, Functions Palette, cc bn cung cp cc chc nng ngi s dng c th to v thay i trn Front Panel v Block Diagram4.3.2.1. Tool PanelTool Panel xut hin trn c Front Panel v Diagram. Bng ny cho php ngi s dng c th xc lp cc ch lm vic c bit ca con tr chut. Khi la chn mt cng c, biu tng ca con tr s c thay i theo biu tng ca con tr .Nu thit lp ch t ng la chn cng c v ngi s dng di chuyn con tr qua cc i tng trn Front Panel hoc Block Diagram, Labview s tu ng la chn cng c ph hp trn bng tool palette. truy cp vo Tool Palette ta chn Menu: View/Tools palette. Cc cng c Tool Palette gm c:

4.3.2.2. Bng iu khin (Controls Palette) Bng iu khin ch duy nht xut hin trn front Panel. Bng iu khin cha cc b iu khin (control) v cc b hin th (Indicator). Bng iu khin c minh ha hnh sauBng iu khin c s dng thit k cu trc mt hin th gm cc thit b: cc cng tc, cc loi n, cc loi mn hnh hin th Vi bng iu khin ny, ngi s dng c th chn cc thit b chun do hng cung cp. Bng iu khin dng cung cp d liu u vo v hin th kt qu u ra.

Hnh 19: Bng iu khin (Controls Palette)4.3.2.3. Bng chc nng Functions PaletteBng Funtions palette ch xut hin trn Block diagram. Bng ny cha cc VI v cc hm m ngi s dng xy dng xy dng nn cc khi lu . Bng Function palette c minh ha trong hnh.Vi bng Function palette, ngi lp trnh thc hin cc c php nh: Php lp, php la chn thng qua cc nhm hm, chc nng c cung cp bn cnh t bng ny ngi s dng ngi s dng c th to ra v s dng li cc hm. Cc hm ton hc c minh ha thng qua cc biu tng. Khi mun la chn thc hin mt hm no th ngi s dng chn biu tng th hin cho hm v c th ko th bt k v tr no trn Block Diagram sau xc nh nhng u vo v u ra cn thit.

Hnh 20: Bng chc nng Functions Palette4.3.3. Cc khi lp trnh thng dngCc khi c bn thng c s dng: Cc k hiu trong ton hc: Functions/ Numeric /Numeric

Hnh 21: Cc k hiu trong ton hc Cc ton t so snh: Functions/Comparison/Comparison

Hnh 22: Cc ton t so snh Khi PID: Control design & Simulation / PID 23: Khi PID Khi biu din th: Controls /Express/Grap Indicator

Hnh 24: Khi biu din th Cc hm: Functions/ Programming/Structures

Hnh 25: Cc hm

Cc bin: Controls/Numeric controls

Hnh 26: Cc bin Khi kt ni Ni DAQ I/O : Functions/ Express/ Input/ DAQ assist

Hnh 27: Khi kt ni Ni DAQ I/OCHNG 5GII THIU V CARD PCI 62215.1. TNG QUAN V CARD PCI 6221National Instruments PCI-6221 l dng M Series c chi ph thp a chc nng dng thu thp d liu (DAQ) nhm ti u ha cc vn nhy cm v chi ph . Ngoi ra khi xem xt tc cao cc thit b dng M cho tc ly mu nhanh hn 5 ln hoc chnh xc cao ca cc dng M cho phn gii gp 4 ln v chnh xc cao hn.Cc dng thit b chi ph thp M kt hp cc tnh nng tin tin nh b iu khin h thng NI-STC 2 , b khuch i lp trnh c NI-PGIA 2 , v cng ngh hiu chnh NI-MCal tng hiu sut v chnh xc.

Hnh 28: Card PCI 6221

5.2. S NI CHN

Hnh 29: S ni chn

DAQmx b m / thi gian PinsB m / thi gian tn hiuPin mc nh S (Tn)

CTR 0 SRC37 (PFI 8)

CTR 0 GATE3 (PFI 9)

CTR 0 AUX45 (PFI 10)

CTR 0 OUT2 (PFI 12)

CTR 0 A37 (PFI 8)

CTR 0 Z3 (PFI 9)

CTR 0 B45 (PFI 10)

CTR 1 SRC42 (PFI 3)

CTR 1 GATE41 (PFI 4)

CTR 1 AUX46 (PFI 11)

CTR 1 OUT40 (PFI 13)

CTR 1 A42 (PFI 3)

CTR 1 Z41 (PFI 4)

CTR 1 B46 (PFI 11)

5.3. Thng s k thut5.3.1. u vo tng t- 16 u vo Ai t A0.A15 v 8 u vo Ai GND- phn gii: 16 bit - T l ly mu : Ti a 250 KS /s- Di u vo : 10 V, 5 V, 1V, 0V- in p u vo ti a ( Tn hiu+ ch thng thng) : 11V - T s loi b kiu chung CMMR: 92dB- Thi gian chnh xc: 50 ppm t l mu - Thi gian gii quyt : 50 ns- u vo khp ni : DC- Thit b ny: AI+ AI GND: 820AI- AI GND : 820- Nhiu xuyn m : 100 kHz- Bng thng tn hiu nh (-3dB) : 700 kHz- Kch thc u vo FIFO: 4095 mu- Qut danh sch b nh: 4095 mc5.3.2. u ra tng t- 2 u ra A0.0 v A0.1 phn gii DAC : 16 bit chnh xc tng i DNL: 1 LSB n iu: 16 bit m bo Tc cp nht ti a1 knh .....................................833 kS / s2 knh ...................................740 kS / s mi knh3 knh ...................................666 kS / s mi knh4 knh ...................................625 kS / s mi knh Thi gian chnh xc : 50 ppm t l mu Thi gian gii quyt : 50 ns Di u ra : 10 V u ra khp ni : DC Tr khng u ra : 0,2 Dng u ra ti a : 5 mA Bo v qu ti : 25 V Bo v qu dng : 10 mA Trng thi on: 20mV1 Trng thi off: 400 mV 200ms u ra kch thc FIFO : 8191 mu chia s gia cc knh s dng5.3.3. K thut s I/Oc im tnh - Tng s: 24+ 8 (P0)+ 16 (PFI) P1 v ( PFI ) Ng ra mass: D GND Bo v in p u vo : : 20 V in tr ko: 50 khz ti a n 20 khz ti thiuc im dng sng Thit b u cui s dng: Port ( P0) Kch thc cng/mu: ln n 8 bit Dng sng ra ( DO ) FIFO : 2.047 mu Dng sng vo (DI) FIFO : 2.047 mu Tn s: 0-1 Mhz5.3.4. Lp trnh thi gian / B m B m : 2 knh phn gii : 32 bit Xung nhp bn trong: 80 MHz, 20 MHz, 0.1 MHz Xung nhp bn ngoi: 0 MHz- 20 MHz chnh xc: 50 ppm5.3.5. I / O kt ni m t tn hiuBng di y m t cc tn hiu c tm thy trn cc kt ni I / O.Tn tn hiuQuan h HngM t

AI GND--Ng vo Analog ni t: Cc thit b u cui l im tham chiu cho cc php o AI kt thc n v tr li dng sai lch cho cc thit b o khc nhau.Ba quan h ni t AI GND, AO GND, v D GND-c kt ni cng nhau trn thit b.

AI Thay iu voTng t u vo knh 0-15: Mi cp knh AI c th c nh dng nh c hai u vo kt thc n hoc 1 u vo phn bit

AI SENSEAI SENSE 2-u voNg vo Analog Sense: Trong ch NRSE, ti liu tham kho cho mi AI tn hiu l AI SENSE, ti liu tham kho cho mi AI tn hiu l AI SENSE 2.

AO AO GNDu raCc knh u ra tng t 0-3: Cc thit b u cui cung cp in p u ra ca cc knh AO 0-1.

AO GND--u ra tng t ni t: AO GND l tham chiu cho AO .Ba quan h ni t AI GND, AO GND, v D GND-c kt ni cng nhau trn thit b.

D GND--K thut s ni t: Chn ny cung cp cho cc tn hiu s ti cc u ni vo/ra nh cung cp ngun DC +5V v cc chn P0. , PFI / P1/P2. Ba quan h ni t AI GND, AO GND, v D GND-c kt ni cng nhau trn thit b.

5 VD GNDu vo hay u ra5 V Ngun in-Cc thit b u cui cung cp mt ngun in 5 V.

PFI / P1. PFI / P2. D GNDu vo hay u raGiao din lp trnh chc nng hay k thut s I / O knh 0-7 v knh 8 n 15-Mi thit b u cui c th c cu hnh ring nh mt thit b u cui PFI hoc mt thit b u cui k thut s I / O.Nh mt u vo, miPFIthit b u cui c th c s dng cung cp mt ngun bn ngoi cho AI, AO, DI, DO v tn hiu thi gian hoc truy cp / m thi gian u vo.Nh mt u ra PFI, C th nh tuyn nhiu khc nhau trong AI, AO, DI, DO hoc tn hiu thi gian cho mi thit b u cui PFI.Bn cng c th nh tuyn cc truy cp / gi u ra cho mi thit b u cui PFI.

NC--Khng kt ni-Khng kt ni tn hiu vi cc thit b u cui.

CHNG 6THIT K PHN CNG V GIAO DIN IU KHIN6.1. PHNG N THIT K 6.1.1.Yu cu thit kTo c h thng iu khin tc ng c c hi tip, bao gm c phn thit k phn cng v to giao din iu khin trn my tnh.6.1.2.Thit kV thit k phn cng: Bao gm mch iu khin v mch cng sut + Mch iu khin: S dng card PCI 6221 + Mch cng sut: s dng mch iu khin cu H dng L298+ Dng phn mm Labview giao tip v iu khin6.1.3. Modul Driver L298 :Thnh phn chnh trong modul cng sut ny l IC L298. L298 l mt Driver tch hp 2 mch cu H bn trong vi chun iu khinTTL, khng c diode ni bo v MOSFET, chu ti ti a trn mi cu l 2A, in p vo ti a l 40VDC. Logic 0 ng vo ln ti 1.5V ( kh nng kh nhiu cao)S nguyn l mch cng sut L298:Hnh 30 : S Modul Driver L298Cc chn IN1,2,3,4 l cc tn hiu u vo, hai chn C,D, A,B iu khin ng ra ng c, chn Enable dng lm u vo bm xung PWM iu khin tc ng c, ta ch cn iu chnh ln Duty - cycle ca PWM l ta c th iu chnh in p cp vo ng c.C 2 mch cu H trn mi chip L298D nn c th iu khin 2 i tng ch vi 1 chip ny. Mi mch cu bao gm 1 ng ngun Vs, mt ng current sensing (cm bin dng), phn cui ca mch cu H khng c ni vi GND m b trng cho ngi dng ni mt in tr nh gi l sensing resistor. ng c s c ni vi 2 ng OUT1, OUT2 (hoc OUT3, OUT4 nu dng mch cu bn phi). Mt chn En (EnA v EnB cho 2 mch cu) cho php mch cu hot ng, khi chn En c ko ln mc cao, mch cu sn sang hot ng. Cc ng kch mi bn ca mch cu c kt hp vi nhau v nhng mc in p ngc nhau do mt cng Logic NOT. Nh vy, s c 2 ng kch cho mi cu H gi l In1 v In2 (hoc In3, In4). motor hot ng chng ta phi ko 1 trong 2 ng kch ny ln cao trong khi ng kia gi mc thp, v d In1=1, In2=0. Khi o mc kch ca 2 ng In, ng c s o chiu quay. Ngoi ra, trn chip L298D cn c cc ng Vss cp in p cho phn logic (5V) v GND chung cho c logic v motor.6.1.4. Phng php iu khiniu khin ng c DC bng cch iu bin rng xungng c DC s dng trong dn dng thng ch hot ng in p 24V tr li. Mt trong nhng phng php iu khin m t l s dng mch iu ch rng xung (PWM circuit - Pulse Wide Modulation). Mch iu khin m t bng phng php PWM hot ng da theo nguyn tc cp ngun cho m t bng chui xung ng m vi tc nhanh. Ngun DC c chuyn i thnh tn hiu xung vung (ch gm hai mc 0 volt v xp x in p hot ng). Tn hiu xung vung ny c cp cho m t. Nu tn s chuyn mch ln m t s chy vi mt tc u n ph thuc vo mmen trc quay. Vi phng php PWM, iu chnh tc ca m t thng qua vic iu ch rng ca xung, tc l thi gian "y xung" ("on") ca chui xung vung cp cho m t. Vic iu chnh ny s tc ng n cng sut trung bnh cp cho m t v do s thay i tc ca m t cn iu khin.Nh trn hnh, vi dy xung iu khin trn cng, xung ON c rng nh nn ng c chy chm. Nu rng xung ON cng ln (nh dy xung th 2 v th 3) ng c DC chy cng nhanh

6.2. GIAO DIN IU KHIN BNG MY TNH6.2.1. Front Panel v Block diagram ca chng trnhXy dng mt VI dng iu khin tc ng c theo PIDFront PanelBlock Diagram 6.2.1.1. Kt ni Dac c gi tr encoder

S dng Couter Input-Edge cout

Chn kt ni Crt 0 hoc Crt 1 ty chn kt ni encoderTa chn Crt 0 ng vi chn encoder A l 37 v B l 45c thng s cho Dac:

6.2.1.2. Kt ni u ra xut xung PWM Analog Output

Chn NiDaQ- Analog Output- VoltageChn knh A0.0 hoc chn A0.1 ty chn tng ng chn 21 v 22 trong PCI 6221

Thay i gi tr in p ra t 0-5v

6.2.1.3. Khu hiu chnh PID Khu PID trong Labview s dng b Pid s 2:Theo phng php hnh thang bin i z PID :

t :

6.2.1.4. To nt tt dng

Khi s dng hm T/F: ng c s chy khi mc True cho php xung ra t PID v s dng mc FALSE ng vi gi tr ng ra bng 0.6.3. Giao din v chng trnh6.3.1. Giao din chnh Front Panel

Hnh 31: Giao din chnh Front Panel

6.3.2. Chng trnh Block Diagram

Hnh 32: Chng trnh Block Diagram6.4. Kt qu t c

Hnh 33: Kt qu t c6.5. M hnh thc nghim6.1. Hnh nh 1Hnh 34: M hnh thc nghim 16.5.2. Hnh nh 2

Hnh 35: M hnh thc nghim 2

KT LUN

Mc tiu ca cc h thng iu khin l ngy cng nng cao cht lng cc h thng iu khin t ng. Ngy nay cng vi s pht trin rt mnh m ca cng ngh thng tin th cc ng dng ca my tnh vo cuc sng ngy cng rng ri. Vi cc tnh nng mm do, chnh xc, nhanh chng h thng iu khin s bng my tnh v ang dn chim u th so vi cc phng php iu khin phn cng thng thng. y l mt ngnh mi m song li rt c trin vng c bit trong cc lnh vc nh my chnh xc, cng ngh mi, hin i ni i hi h thng iu khin phi c chnh xc cao, kh nng thay i mm do. Mt trong nhng ng dng c th m c s dng trong thc t l h thng iu khin tc ng c. Trong n ny , chng em s trnh by phng php phn tch, tng hp h thng cng vi phn cng v phn mm cho h thng iu khin tc ng c. Vi kt qu thu c t m phng, ng gp c cc vn sau:nh hng ca cc thng s PID n h thng nh sau:. iu khin t l (KP) c nh hng lm gim thi gian ln , vt l v s lm gim nhng khng loi b sai s xc lp. iu khin tch phn (KI) s loi b sai s xc lp nhng c th lm p ng qu xu i, lm tng hoc gim thi gian xc lp. iu khin vi phn (KD) c tc dng lm tng s n nh ca h thng, gim vt l v ci thin p ng qu Sau cng mt ln na chng em xin chn thnh by t lng bit n i vi thy Nguyn Ngc Sn v cc thy c trong khoa, gip chng em hon thnh n ny!Chng em trn thnh cm n!!!

TI LIU THAM KHO[1] Gio trnh mno lng v iu khin bng my tnh- TS.Nguyn c Thnh - HBK TP.HCM.[2] Bi gingo lng v iu khin bng my tnh- ThS.Hunh Minh Ngc H Cng Nghip Tp HCM[3] Nguyn Phng Quang, Bi ging iu khin s[4] Nguyn B Hi, Lp trnh LabVIEW Trnh c bn, Trng i hc S Phm K Thut TP.HCM 2011[5] Internet:http://digital.ni.com/manuals.nsf/websearch/2025C99AB0614F9E8625748000577B9Ahttp://forums.ni.com/attachments/ni/40/5529/1/622xhttp://cyberlab.com.vn/vi/http://www.dientuvietnam.net/forums/forum.phphttp://hocdelam.org/site1/index.html

Ref_input

Mea_input

Ctr_output

P_sel

I_sel

D_sel

_

+

Actuatormodel

-y

E= r - y

Actuator