K YU HI NGH SINH VIN NGHIN CU KHOA HC NM 2009

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THIT K V CH TO B IU KHIN V TR NG C GIAO TIP VI MATLAB Sinh vin: Nguyn Vit Thun - CBHD: Ths. Dng Quc Bo Chng trnh o to k s

cht lng cao Vit Php PFIEV Nng

Tm tt: iu khin chnh xc v tr ng c in mt chiu l 1 trong cc yu cu quan trng nht ca cc h thng iu khin cng nghip. Mc ch chnh ca bi bo ny l nghin cu v ch to b iu khin v tr ng c s dng gii thut PID, S-curve Trajectory v truyn thng vi my tnh bng phn mm Matlab. Gii php ny cho php mang li nhiu u im cho b iu khin hn l PID truyn thng. T kt qu nghin cu ny ta c th ng dng xy dng cc h thng iu khin ng c trong cng nghip..

Abstract: Precision-motor position controlling is one of the most important requirements in industrial controllers. The main object of this paper is studying and designing a motor position controller using PID algorithms, S-curve Trajectory and communicate with Matlab. This solution could bring more advantages than conventional PID. We can apply the results of this paper to designing industrial motor controller.

I. M u

1. L do chn ti: Hin nay nc ta ang trong giai on cng nghip ha. Vic s dng cc my CNC v cc

tay my cng nghip ngy cng ph bin trn c nc. Cc thit b ny yu cu cao v iu khin v tr v n nh. Tuy nhin, do a s cc my mc ny u nhp t nc ngoi nn khi c hng hc th vn khc phc rt tn km v mt nhiu thi gian. C nhiu gii php c a ra nhm gii quyt vn ny. Cc b iu khin trong nc l

1 hng i tch cc. Tuy nhin vic thay th hon ton 1 h thng iu khin s gp nhiu kh khn, Do vic hng ti vic ch to cc thit b iu khin trong nc theo tng module l 1 hng i ng quan tm. Gii thut PID kinh in c ng dng rng ri trong cng nghip c th l 1 gii php tt.

Tuy nhin vi yu cu iu khin v tr ng c th PID truyn thng bc l 1 s nhc im v gim vt l. Do , ng dng gii thut PID kinh in kt hp vi iu khin qu o v thc hin gim st bng my tnh c th l 1 gii php t tn km v ph hp vi iu kin thc t sn xut.

2. Mc ch nghin cu v phm vi nghin cu 1) Nghin cu ng dng gii thut PID cho vi iu khin PIC18f4550. 2) Nghin cu phng php iu khin ng c. 3) Nghin cu truyn thng gia vi iu khin v my tnh s dng Matlab. 4) Nghin cu v gii thut thc hin S-curve. 5) Nghin cu, thit k v ch to mch iu khin ng c.

K YU HI NGH SINH VIN NGHIN CU KHOA HC NM 2009

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3. Phng php nghin cu 1) Da vo cng thc ca PID lin tc v S-curve lin tc xy dng PID ri rc v S-curve ri rc nhm p dng trong vi iu khin. 2) Phn tch cc u v nhc im ca cc phng php iu khin ng c v la chn phng php iu khin ph hp vi yu cu ca ti. 3) S dng Instrument Toolbox ca Matlab xy dng truyn thng iu khin v gim st qu trnh iu khin. 4) Thi cng mch iu khin s dng PIC18f4550 v IC TCA785 thc hin iu khin pha.

II. Tng quan iu khin ng c l 1 lnh vc pht trin t lu. Do khi thit k th c rt nhiu gii

php a ra p ng cc yu cu. Trong cc phng php iu khin ng c th phng php chnh lu iu khin pha l 1 k

thut ph bin v mang li kh nng ng dng cao hn so vi cc phng php khc trong cc my mc v dy chuyn cng nghip. Vi th mnh l 1 cng c lp trnh mnh m dnh cho tnh ton v kh nng m phng h

thng iu khin nn Matlab l phn mm c ng dng rng ri trong cc hot ng nghin cu. Trong ti ny, Matlab c s dng truyn v nhn tn hiu phn hi nhm nh gi cht lng ca b iu khin. Trong nhng nm gn y, vi iu khin v ang c s dng rng ri trong cc ngnh

cng nghip. Mc d PLC vn l s la chn hng u cho cc h thng ln th u im ca vi iu khin l n nh ngy cng cao, kh nng lm vic theo tng modul nh, n gin trong lp trnh, mm do vi cc ng dng khc nhau cng nh gim c chi ph u t. Vi yu cu v 1 modul iu khin ng c th vi iu khin c s dng trong ti ny.

III. Nhng nghin cu thc nghim hoc l thuyt 1. Giao tip RS232 dng Matlab

Matlab cung cp Instrument Control Toolbox l 1 cng c cho vic kt ni cc thit b vi cc chc nng chnh sau.

1) To ra i tng truyn thng trn matlab ( instrument objects): Hm serial to ra 1 i tng. Hm ny yu cu tn ca cng COM m i tng kt ni. 2) Ci t thng s truyn thng :BaudRate , Databits , Parity , StopBits , Terminate 3) Kt ni i tng ny vi thit b: Ta s dng hm fopen() bt u kt ni vi thit b. 4) Truyn v nhn d liu 5) Ngt v hm phc v ngt: Khi truyn thng, nu c 1 s kin ( c xc nh ) xy ra th s xy ra 1 ngt v chng ta c th gi cc hm phc v ngt. 6) Thit k phn mm iu khin dng Matlab: Cc chc nng chnh ca phn mm:

a) Ci t cc thng s cho cng truyn thng. b) Chn cc gi tr Kp, Ki, Kd cc gi tr mong mun v truyn xung vi iu khin. c) Thu nhn tn hiu phn hi t vi iu khin gi ln v v th

K YU HI NGH SINH VIN NGHIN CU KHOA HC NM 2009

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Giao din phn mm c thit k trn Matlab.

2. Thit k qu o S-curve Vi yu cu b iu khin phi c kh nng phi

hp chuyn ng ca nhiu ng c khc th vic thit k qu o cho ng c l bt buc m bo qu o ca c cu chp hnh. Cc yu t bit trc: v tr yu cu, vn tc yu

cu, gia tc a. Tnh ton:

20 0

0 0

0

_ ; _ ; _ _ _ 2. _2

_ _

_ _ ; _ _ 2 _

v vt ttoc y ttoc y deu y ttoc y der y ttoc

a a

y deu y ttoct deu t ttoc t giamtoc t deu t ttoc

v

= = = +

= + = +

Giai on 1 : t < t_ttoc 2

0 01

; 2

y a t v a t= =

Giai on 2 : t_ttoc < t < t_deu 0 0_ ( _ ) ; y y ttoc v t t ttoc v v= + =

Giai on 3 : t_deu < t < t_giamtoc 2

0 0 0 01

_ ; 2

y y deu v t a t v v a t= + =

Tuy nhin trong thc t ta khng th tnh ton vi thi gian t lin tc. Do ta phi ri rc ha cc cng thc trn vi mu thi gian l step_time . Nh vy ta nhn c cc cng thc sau: ( vi m_... l s im mu thi gian).

_ _

_ ; _ _ 2 _ ; __ _

t deu t giamtocm deu t giamtoc t deu t ttoc m giamtoc

step time step time= = + =

K YU HI NGH SINH VIN NGHIN CU KHOA HC NM 2009

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KHI NGUN IU KHIN

KHI PHT XUNG KHI IU KHIN

KHI KCH THYRISTOR

KHI CHNH LU NG C

KHI PHN HI.

KHI NGUN NG LC

MATLAB

Giai on 1 : t < t_ttoc 2

0 01 ( _ ) ; _2

y a m step time v a m step time= =

Giai on 2 : t_ttoc < t < t_deu 0 0_ ( _ ) _ ; y y ttoc v m m ttoc step time v v= + =

Giai on 3 : t_deu < t < t_giamtoc

[ ]20 00 0

1_ ( _ ) _ ( _ ) _

2( _ ) _

y y deu v m m deu step time a m m deu step time

v v a m m deu step time

= +

=

3. Thit k v thi cng mch iu khin

1) Khi ngun iu khin: Cp ngun 5V, 12V, 15V,-15V n nh cho mch iu khin. 2) Khi iu khin : Gm PIC18f4550, DAC0808, Max 232 lm nhim v tnh ton, a ra in p analog iu khin, nhn encoder phn hi v truyn thng vi Matlab. 3) Khi pht xung : Gm 2 IC TCA785 lm nhim v pht hin im khng, nhn in p iu khin t khi iu khin v a ra xung kch ng thi im. 4) Khi kch Thyristor : Gm cc mch khuch i xung kch kch m Thyristor. 5) Khi chnh lu : Gm 8 thyristor 2P4M. 6) Khi ngun ng lc : Ngun cung cp 24 VAC. 7) C cu chp hnh : ng c in 1 chiu 30V, . 8) Khi phn hi : Incremental rotary encoder 200ppr. 9) Khi Matlab : truyn thng v iu khin bng my tnh.

K YU HI NGH SINH VIN NGHIN CU KHOA HC NM 2009

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4. Kt qu thu c

th n nh vn tc ng c khi c ti th n nh v tr ng c ng mu lc : Tc thc t ng mu en : Tc mong mun

ng mu : Qu o iu khin ng mu xanh : V tr mong mun ng mu lc : Qu o thc t

iu khin chnh xc v tr ca ng c vi chnh xc kh cao. n nh vn tc ca ng c khi c ti v khng ti. Thu nhn tn hiu phn hi v v th dng Matlab thnh cng.

IV. nh gi kt qu nghin cu ny, vt l c gim ti a vi sai s nh. Trn c s ny c th pht trin cc

k thut hin i hn v s dng h iu hnh thi gian thc ch to cc b iu khin phc tp hn dng phi hp nhiu ng c trong my CNC v tay my robot. Ta c th s dng Matlab Compiler Toollox to ra file chay c lp cho cc my tnh khng ci phn mm Matlab.

V. Kt lun

Vic ng dng cc phng php iu khin hin i vo iu khin ng c l rt cn thit v ngy cng ph bin. Vi nhng kt qu t c, ti ny c th l mt hng i nhm gim gi thnh v mang li hiu qu cao trong thc t.

Li cm n

Em xin gi li cm n chn thnh n thy Dng Quc Bo v cc thy c trong chng trnh PFIEV, gip em tn tnh v k thut v to iu kin tt nht em c th hon thnh tt ti.

Ti liu tham kho [1] George W. Younkin, Industrial Servo Control Systems. New York: Marcel Dekker, 2003, ch 4. [2] Mathworks, Instrument Control Toolbox Users Guide. [3] Ts. Phm ng Phc, Robot cng nghip. chng 4. [4] Mathworks, Matlab 7.0 and Simulink 6.0 help.