CHNG 1 GII THIU CHUNG

1.1 Gii thiu chung

Chng ta khng th ph nhn rng mt l c quan c cu to tinh vi nht ca con ngi. N lu gi mi hnh nh v gi v no b x l thng tin.Mt gm c nhn cu, dy thn kinh v nhng b phn ph thuc nh m mt, lng mi, cc c mt, cc gn mc, tuyn l v mng tip hp.

Nhn cu l phn chnh yu nht, thng c so snh vi chic my nh v c tnh chnh xc quang hc ca n.

Nhn cu gm 3 lp mng tn gi l:

Mng ngoi gm cng mc v pha trc bin i thnh gic mc. Mng gia l mng b o, thn b v mch mc, cha nhiu mch mu, pha trc dy ln thnh c th mi v mng mt.

Mng trong l vng mc, cha cc t bo nhy cm nh sng l t bo gy v t bo nn.

Cng ngh TET (Tracking eye technology) l cng ngh theo di chuyn ng ca mt, s dng my tnh xc nh v tr ca mng mt ( iris). T gip chng ta c th iu khin c cc thit b bng my tnh. Cng ngh iu khin bng mt vn cn rt mi m ti Vit Nam. chng ta ch bit cng ngh qua nhng chic in thoi smatphone vi nhng tin ch nh cun trang, dng video...Da trn cng ngh nhm pht trin ti: Nghin cu, thit k, ch to robot di ng iu khin bng cng ngh TET. Nhim v c th ca nhm l thit k ch to mt m hnh robot di s iu khin trc tip ca mt ngi. Robot c kh nng di chuyn linh hot.

1.2 Cc vn t ra

Vi ti : Nghin cu, thit k, ch to robot di ng iu khin bng cng ngh TET vic thit k v ch to nhm c mt s vn cn gii quyt:

Trong vic thit k v ch to h thng c kh cho robot phi chnh xc m bo tnh thm m, s chc chn v hot ng n nh ca robot. Vn gim st v x l nh: trn th trng c nhiu loi webcam ( hay camera) vi gi c, tin cy, phn gii, tc x l khc nhau. Vic chn la cng l vn kh khn. Vic thit k webcam cng l mt vn kh khn trong vic x l: webcam thit k phi nh gn, linh ng, ph hp vi iu kin ca ti. Vic xy dng thut ton v phng php iu khin gp nhiu kh khn:Thut ton x l nh va phi d tm chnh xc, gim c nhiu trong qu trnh x l v tnh ton xc xut c tn hiu iu khin, gim tr m bo tc p ng v phi d phng c cc li xy ra trong qu trnh hot ng.

Lp trnh iu khin v thu pht d liu: Xy dng thut ton iu khin ng c DC s dng vi iu khin PIC 16F877A. Xy dng thut ton thc hin vic thu pht tn hiu khng dy s dng module NRF24L01 2.4Ghz vi vi iu khin PIC 16F877A.

1.3 Phng php nghin cu

iu khin bng phng php truyn tn hiu khng dy l mt phng php iu khin tin tin ngy cng c ng dng nhiu v trn th trng cng c nhiu sn phm thng minh p dng phng php truyn tin ny. iu khin robot t ng c trn th gii nhng vn cn mi l ti vit nam. Vi vic nghin cu n ny s m ra nhiu iu mi l trong lnh vc iu khin robot bng x l nh. T p dng thit k trong gii hn ti.

Kt hp gia vic thit k tun t v ng thi: C th l bc u tin xy dng mt m hnh cha y cc thnh phn d nh s c trong thit k (xy dng khi iu khin, khi ngun, h thng c kh, khi x l nh, thut ton iu khin chung ton h thng) qua c ci nhn tng quan v h thng chung v xc nh thng s c bn. Tip theo da vo bc u tin nhm tin ti xy dng chi tit tng khi i vi mi khi li tin hnh xy dng thut ton trc khi i vo phn lp trnh da trn nguyn tc phi ph hp vi kh nng ca phn cng xy dng. Sau khi hon chnh tng khi tin hnh ghp ni cc khi vi nhau i ti bc tip theo.

Qu trnh th nghim: Nhm da trn kt qu thc t nh gi, so snh ri a ra kt qu hiu chnh v tm ra phng php ti u nht.1.4 Phm vi v gii hn ti Do thi gian, ti chnh v tm hiu bit nhm ch ch to m hnh robot vi nhng c im sau:

Robot s dng trong ti l m hnh xe n gin vi vt liu l inox. S dng module thu pht sng 2.4GHz c kh nng truyn pht sng khng dy trong bn knh width, colorimg->height ), IPL_DEPTH_8U, 1 );

Bc 2: Chuyn i nh mu sang nh a mc xm.

cvCvtColor( img, grayimage, CV_RGB2GRAY );

2.3.3 Nh phn ha vi ngngNh phn ha l qu trnh bin i nh xm thnh nh nh phn. nh nh phn ch cha hai gi tr 0 hoc 1 ( 0 hoc 255 ty theo quy nh cu trc nh) theo gi tr 0 tng ng vi im en trn nh v gi tr 1 hoc 255 tng ng vi gi tr im trng. Cng thc nh phn ha nh l t tt c gi tr im nh v 0 nu chng b hn im ngng T cho trc v v gi tr 1( hoc 255) nu chng ln hn gi tr ngng T . Vn y l xc nh ngng T l rt kh v chng ph thuc vo iu kin nh sng ca mi trng.

Trong Opencv vic ly ngng c thc hin bng cch gi hm:

cvThreshold(const CvArr *src, CvArr *dst, double threshold, double max_value, int threshold_type).

Trong , src l nh gc, v phi l nh xm, dst l nh ch mt knh mu, c cng kch thc vi nh u. Threshold l gi tr ngng ta t cho vic nh phn, max_value l gi tr ln nht ca nh xm, thng thng l 255. threshold_type l kiu threshold m ta mun thc hin, Thng thng l CV_THRESH_BINARY, cn mun nh phn ngc ta dng CV_THRESH_BINARY_INV.

Nh phn ha vi ngng mc ch gip my tnh c th phn bit c vng c chn v vng khng c chn. i vi nh xm chng ta s ch c mt ngng T vi mt gi tr trong khong t [0255] c trng cho gi tr mnh cn phn bit.2.3.4 Cc php ton hnh thi hc trong nhSau khi chuyn thnh nh nh phn my tnh c th phn bit c r rng vng x l nhng vic theo di mt s khng c din ra v vng x l nh, din tch t khng th phn bit c vi nhiu do lng mi. thc hin c qu trnh bm theo chuyn ng ca ng t, chng ta cn phi tng din tch mu trng nhn din ng t tng ln. Qu trnh chng ta p dng php ton ng, c th hiu n gin thut ton ny nhm mc ch thay th mi ln cn mu en ca cc im nh thnh mu trng.

Php dch chuyn A ca im nh x(hng, ct):

(A)x = {c | c = a+x, a A}

Php i ca tp A c nh ngha nh sau:

(A)x={c | c = -a, a A}

l php quay A 180o quanh gc ta

Phn b ca im A l cc i tng khng ph thuc vo i tng A. Theo l thuyt tp hp th :

Ac = { c | c A } Giao ca 2 tp hp ca A v B l tp hp cc phn t thuc c tp hp A ln B k hiu:

A B = {c | ( c A) ( c B) }

Hp ca 2 tp hp A v B l tp ca phn t A hoc / v B k hiu:

A B = {c | ( c A) ( c B) }

Hiu ca 2 tp hp A v B :

A - B = { c | ( c A) ( c B) }

Php dn A bi cu trc B c k hiu :

A B = {c | c = a + b, a A, b B}

Trong C c gi l kt qu ca php dn A s dng phn t cu trc B, tuy nhin vi im trong s chng c th trng nhau.

A=

Trong

hnh a. Tp A ban u.

Hnh b. Tp A cng phn t (0,0).

Hnh c. Tp A cng phn t (0,1).

Hnh d. hp (b) v (c) kt qu php dn

Phn t cu trc:

Hnh 2.10 Dn A bi B

Ta c th nhn thy rng vic xc nh gc ca nh l rt quan trng n s cc nh hng dn ca nh. Nu gc nm bn tri th xu hng dn ca nh nm bn phi. nu gc nm bn phi th xu hng dn v bn tri. Nu gc nm gia th xu hng dn u.

Php gin n (dilation) l tp hp tt c cc php dch chuyn ca cu trc, k hiu:

Tuy nhin vi vai tr bnh ng ca A v B, ta c th coi l A l cu trc v B l nh th khi :

T nhng iu trn c th gip ta tip cn n mt thao tc gin nh c th c my tnh ha. Ta c th xem nhng phn t cu trc nh l mt mu v dch chuyn n trn nh. Khi gc ca phn t cu trc hay mu khp vi nh en trn nh, th tt c nhng im nh tng ng trn cu trc s c nh du v thay th sau. Sau khi ton b nh c qut qua bi mu, thao tc dn nh xem nh hon chnh. Thng thng my tnh s lm nh sau:

Hnh 2.11 Gin nh s dng phn t cu trc

a. Gc cu trc nh v trn im nh u tin v nhng im en cu trc c chp sang nh kt qu nhng v tr tng ng.

b. Qu trnh lp li tng i vi nhng im en tip theo ca nh.

c. Qu trnh hon chnh.

Php ton co (erosion) .

Php ton co trong nh c nh ngha A B={ x |(B)x A } trong A l i tng trong nh, B l cu trc phn t nh. Ta cng s xt mt v d nh trn vi php co trong nh. i tng trong nh c biu din bi mu xm, cu trc phn t nh l khi c vin mu , x l im sau php tha mn php co nh, 0 l im khng tha mn.

Hnh 2.12 Php ton co (erosion)

Ta thy rng sau php ton ny i tng trong nh b co li, chnh v vy m n c ng dng trong vic gim kch thc ca i tng, tch ri cc i tng gn nhau v lm mnh, tm xng i tng.

Php ton ng: A B = ( A B ) B.Php ton ng c ng dng trong vic lm trn ng bao i tng, lp y cc khong trng trn bin v loi b nhng h nh ( mt s pixel ng thnh cm c lp ). Php ton m : A o B=( A B) B.Php ton m dng loi b cc phn li lm cc ng bao tr nn trn v mt hn.2.3.5 Tm vin(contour)i vi phng php tm vin mc ch dng xc nh c khung gii hn bao quanh mt. Khung ny c kh nng thay i khi mt ng hoc m, chng ta c th xc nh c vic ng m mt khi din tch khung thay i.

Nguyn l c bn ca hm contours l sau khi nh c x l thnh nh en trng, tt c cc i tng quy nh c nhn bit s c v mt ng bao bn ngoi bin dng ca chng. Mt bc tip theo l xy dng thut ton so snh nh theo cc tiu chun v kch thc cng nh ta tng ng vi vt cn nhn bit. Sau khi c thut ton hm contours s t ng tnh ton vt c mu sc v kch thc chnh xc nht so vi tiu chun v bin dng chnh xc v hin th duy nht vt .

CvFindContours(img, luutru, &contours, sizeof (CvContour),CV_RETR_LIST, CV_CHAIN_APPROX_SIMPLE, cvPoint(0,0)) y l on code s dng trc tip trong bi ca nhm, Find contours thc hin chc nng v ng bao xung quanh cc vt c nhn bit v mu sc vi kch thc tng ng, cng lc cc ng bao s lu li gi tr v ta trn nh. CV_CHAIN_APPROX_SIMPLE l hm c chc nng loi b cc ng tha v nn ng vin qua tit kim b nh. V d nhn bit mt hnh ch nht chng ta cn v ng vin vi 1000 im nh th nhng vi hm trn chng ta ch s dng 4 im. (Hnh 2.13)

Hnh 2.13 Minh ha s dng CV_CHAIN_APPROX_SIMPLE

2.4 Khi iu khin trung tm

Trong h thng mch in t vi iu khin trung tm ng vai tr l b no, tip nhn, x l v a ra thng tin cho ton h thng. Da trn yu cu v chc nng v tc x l nhm la chon vi iu khin PIC 16F877A ca hng Microchip sn xut, vi mt s chc nng v thng s c bn sau: S dng cng ngh tch hp RISC CPU.

Ngi s dng c th lp trnh vi 35 cu lnh c bn.

Tt c cu lnh thc hin trong mt chu k lnh, ngoi tr mt s cu lnh r nhnh thc hin trong 2 chu k lnh.

Tc hot ng xung ng h l 20MHZ.

B nh hot ng l flash 8k x14 words.

B nh RAM 368x8 bytes.

B nh EFPROM 256x8 bytes.

Kh nng ngt ln n 14 ngt trong v ngt ngoi.

Ngn nh Stack c phn chia lm 8 mc.

Truy cp b nh bng a ch trc tip hoc gin tip.

Ngun khi ng (POR).

B to xung (PWRT) v b to dao ng (OST).

B m thi gian (WDT) vi ngun dao ng trn chp (ngun dao ng RC) hot ng ng tin cy.

C m chng trnh bo v.

Phng thc ct gi SLEEP.

C bng la chn dao ng.

Cng ngh CMOS FLASH/EFPRO ngun mc thp tc cao.

Thit k hon ton tnh.

Mch chng trnh ni tip c 2 chn.

Mch x l c ghi ti b nh chng trnh.

Di in th hot ng 2.0 n 5.5V.

Ngun in s dng 25mA.

Dy nhit cng nghip v thun li.

Cng sut tiu th thp. TIMER0: 8 bits ca b nh thi, b m vi h s t l trc.

TIMER1: 16 bits ca b nh thi, b m vi h s t l trc, c kh nng tng trong khi ch sleep qua xung ng h c cung cp bn ngoi. TIMER2: 8 bits ca b nh thi, b m vi 8 bits ca h s t l trc, h s t l sau.

S chn ca PIC 16F877A

Hnh 2.14 S chn ca PIC 16F877AChn 13, 14 l cc chn kt ni vi thch anh to dao ng cho chip. Ta mc thm vo 2 t in c in dung =33pF tng n nh cho dao ng thch anh.

PORTB v PORTB lc ny ng vai tr l ng xut nn cc thanh ghi TRISB trong chp phi c t gi tr logic 1 (Nu ta t ng B l ng nhp th ta phi t gi tr logic 0). VDD: L in p cp ngun cho vi iu khin, ngun in cp l 5V.

GND: L chn ni mass khi s dng cn thit k mt mch n p bo v cho vi iu khin , thng s dng IC n p 7805.

PORTA: C 6 pin t chn 2 n chn 7.

PORTB: C 8 chn t 34 n 40, ngoi chc nng lm cng xut nhp cn c thm mt s chc nng ph khc.

PORTC, PORTE: Tng t nh PORTB.

Chn Reset (MCLR): Ng vo chn 1 dng thit lp iu kin u cho vi iu khin.

OSC1, OSC2: Hai chn ny c s dng nhn ngun xung clock t bn ngoi c th l t thch anh dao ng.

Cc chn RC3, RC4 dng kt ni I2C.

Cc chn RC6, RC7 l chn kt ni RS232.

2.4.1 Giao tip UART trong PIC 16F877ATrong PIC16F877A c tt c nm thanh ghi cho qu trnh iu khin UART: Bao gm hai thanh ghi chc nng TXSTA, RCSTA, hai thanh ghi d liu RCREG v TXREG. Thanh ghi tc baund SPBRG .Trong PIC16F877A c hai ch truyn High speed v Low speed c quy nh bi Bit BRGH ca thanh ghi TXSTA. Vic phn chia hai mc tc ny c s chn la cho trng hp sai s vi tc baud chun ca PC: M trong PC c cc mc chun: 300, 2400, 9600, 19200, 28800

Trong PIC16F877A c nhiu ch truyn nhn khc nhau: Ch truyn nhn dng bit 9 nh chn l, hay cho mng vi iu khin mt master v nhiu slave. V ch chuyn ng b ng dng cho vic giao tip vi A/D, D/A hay vi cc EEPRO. Cc ch ny s c thit lp bi cc bit trong thanh ghi TXSTA, v TCSTA.

Qu trnh nhn d liu: Trong PIC16F877A nhn bit c d liu truyn ti ngi ta dng bit c RCIF trong thanh ghi PIR1. Nh vy khi thanh ghi m d liu cha d liu th RCIF s c a ln 1 v chnh c ny cho php PIC16F877A c hai phng thc nhn bit lc no c d liu truyn ti. S dng ngt v s dng kiu Polling (quay vng). Qu trnh truyn d liu: Trong qu trnh truyn d liu cng c hai ch s dng ngt v Polling , tuy nhin qu trnh truyn d liu ln PC khng phi l thi dim bt k m dt di s kim sot ca chng trnh cho nn ngi ta thng s dng kiu polling khi cn truyn th truyn i.2.5 C cu chp hnhng c DC cng l mt c cu chp hnh c-in, bin nng lng in thnh cc chuyn ng c hc. ng c DC hot ng c da trn 2 nh lut Loren v Faraday. Cu to ca ng c DC gm phn ng, phn kch t, chi than v c gp. C 5 loi ng c DC l : ng c kch t ni tip, ng c kch t song song, ng c kch t hn hp, ng c kch t c lp v ng c nam chm vnh cu.

Hnh 2.15 Cu to ng c DC

Cc trng hot ng ca ng c DC kh n gin, phn tch da trn ng c tnh c ca ng c. Gm cc trng thi khi ng v trng thi hm. Do ng c tnh c l mt ng thng, nn vic phn tch s ph thuc ca momen v vn tc ca ng c cc trng thi n gin.

Hnh 2.16 ng c tnh c ng c DC

2.6 Mch cng sut iu khin ng cVi ti ny nhm chn 2 ng c DC 24v vi cng sut nh, thun li cho vic iu khin nhm chn module L298 iu khin ng c.2.6.1 Module L298Dual H-Bridge Module s dng ICST L298N tch hp nguyn khi 15-pin kiu Multiwatt, in p v dng ti cao, c thit k chp nhn mc in p logic tiu chun TTL v ti in cm nh Solenoids, 2 ng c DC hoc 1 ng c bc dy.Hai Enable inputs cho php kch hot (enable) hoc v hiu ha (disable) cc thit b c lp ca tn hiu u vo. Cc E ca cc Transistor di ca mi cu c ni vi nhau v a ra bn ngoi (chn SENSE A v SENSE B) c th ni vi mt in tr c th cung cp mt ngun u vo b sung logic lm vic vi in p thp hnTham s sn phm:

S dng L298 gm 2 mch cu H iu khin ng c DC.

in p cung cp: +5V n +35V.

Dng in ti a: 2A.

Dng tiu th 0 ~ 36mA.

Tin hiu iu khin in p uvo:

Mc thp: 0,3