hệ thống robot thông minh (1)

7/28/2019 H thng Robot thng minh (1)

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H thng Robot thng minh

Ngc : 1-2-22 Phan: 3-4 Sinh: 5-6 ip: 7-8

Tng lt: 9+15 Tun Anh: 10-11 Chung: 12-13 Hoan:16-17

Tungcl: 18-19 Thy :20-21 Linh 14+15 Hng: 3+23

1 Phn bit robot cng nghip v robot thng minh. Trnh by s phn

nhnh trong pht trin Robot ti nhng thp nin gn y.RBCN l tay my vn nng, hot ng theo chng trnh v c th lp trnh li hon thnh v nng

cao hiu qu hon thnh cc nhim v khc nhau trong cng nghip, nh vn chuyn nguyn vt liu,

chi tit, dng c hoc cc thit b chuyn dng khc.

RBTM l mt loi vt c kh c khnng hot ng mt cch t tr. Ni cch khc n khng phi l 1 c

my ch thc hin nhng nhim v lp i lp li ging nh nhng cmy thng thng.Robot c khnng tng tc vi th gii bn

ngoi (di chuyn, thay i thgii

bn ngoi,) trong khi RBCN

khng c kh nng ny. RBTM c

th hoat ng c lp trong mi

trng m khng cn ngi iu

khin.

S phn nhnh trong pht trin

Robot (Hnh v)

2 nh ngha Robot thng minh?Robot thng minh l mt loi vt c kh c th hot ng mt cch t tr. Mt robot c th s dng

my tnh lm mt khi chc nng bn trong n, tng tnh b no. Robot c khnng tng tc vi

thgii bn ngoi (di chuyn) trong khi my tnh k c khnng ny. Hot ng mt cch t trngha l

robot c th vn hnh c lp trong mi iu kin m khng cn n ngi iu khin, t thch nghi vs

sthay i trong mi trng ca n tip tc t ti mt mc ch no .

T thong minh y ni ln rng robot khng lm vic mt cch n gin, lp i lp li nh cc h

thng tng trong cc nh my. Loi vt c kh ni ln rng cc b phn ca robot lm bng c kh.Tuy nhin, n nay v trong tng lai, cc b phn c thc thay thbng cc cu trc sinh vt hu

c nh cc k thut cy ghp hay sinh sn v tnh. nh ngha nh vy cng nhn mnh rng: robot

khng phi l ci my tnh. Mt robot c th dung mt my tnh lm 1 khi chc nng bn trong n,

tng tnh bno. Nhng robot li c khnng tng tc vi th gii bn ngoi (di chuyn y ,

lm thay i thgii,) trong khi my tnh th khng c khnng ny. Hot ng mt cch t tr ni

ln rng robot c th vn hnh c lp trong mi iu kin m khng cn n ngi iu khin. Khi


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nim t qun trc ngh l robot c th thch nghi vi sthay i ca mi trng ca n tip tc t

ti mt mc tiu no y.

3 Trnh by 3 loi m hnh c thit kcho mt robot thng minh

3.1 M hnh kiu th bc:Robot vn hnh theo cch t trn xung, xem nng vic lp khoch. loi ny, robot cm nhn mi

trng xung quanh, nh khoch cho hnh ng ktip v hnh ng (Sense-Plan-Act). Sau n lp

li qu trnh ny mi bc. Tt c cc thng tin cm nhn c tp hp li vi nhau trong mt m

hnh th gii ton cc. Chng c th c b lp k hoch s dng hay c th c cp ti cc b

hnhd ng

3.2 M hnh kiu phn ng:M hnh ny c sinh ra bi cc nh nghin cu robot thng minh s dng kt qu khm ph v

tm l sinh vt v nhn thc ca chng vi mi trng v do s gim gi nhanh chng ca phn cngmy tnh cng vi s tang cng nng lc tnh ton ca my tnh v cc b x l. Mt m hnh kiu

phn ng c th bi khu lp khoch v tr thnh loi t chc cm nhn-hnh ng (sense-act). Li

vo ca hnh ng lun l li ra trc tip t b cm nhn (sense-act). M hnh ny c thi gian chp

hnh nhanh do khng cn vic lp khoch. Kt qu l m hnh phn ng cung cp nhng c s cho h

thng lai gia cn nhc/ hnh ng.

3.3 M hnh kiu lai:u tin robot lp khoch (cn nhc) phn chia mt cch tt nht nhim v thnh cc nhim v con

(gi l lp khoch nhim v) v cc ng x thch hp thc hin cc nhim vy l g Sau cc

ng x bt u thc hin nh m hnh phn ng.

Cch t chc ny gi l lp khoch - cm nhn- hnh ng (P,S-A) trong du phy ch ra lp k

hoch c thc hin mt bc, sau cm nhn v hnh ng sc thc hin cng nhau. T

chc cm nhn h thng lai cng l s trn ln gia kiu th bc v kiu phn ng. D liu t cc cm

bin c cap ti mi bng x cn chng, nhng cng c sn cp ti b lp khoch xy dng

m hnh mi trng ton cc hng nhim v. B lp khoch c thcng nghe ln trn cc cm

nhn ca mi bng x (tc l bng x nhn ra cc tr ngi m c th cn a vo bn i mi

trng ca b lp khoch). Mi chc nng tin hnh vic tnh ton tc ring ca n, ln khoch

k cng. Th d, cc tnh ton chung thng c cp nht sau mi ln 5s, trong khi bng x phn ng

thng thc hin ch trong khong 1/60s trong cc robot di ng vi tc c 80cm/s.

4 Cc thnh phn c bn ca mt ro bot thng minh t qun tr(Phan)


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5 Trnh by tm tt nguyn tc hot ng v u nhc im ca cc

loi cm bin: lp m trc quay, cm bin chhng, cm bin siu

m pht hin vt th gn, cm bin nh, cm bin o khong cch

bng laser

5.1 Cm bin lp m trc quay:- Cm bin lp m trc quay l loi cm bin ni c s dng ch yu cc robot di ng

do tnh n gin ca n, nht l dung trong cc trng hp iu khin robot di chuyntrong khong cch ngn

- Nguyn l hot ng: l mt a trn xoay quay quanh trc, trn a c cc l (hocrnh). Dng n led chiu ln mt a. Khi quay, ch khng c l(rnh) th n khngth chiu xuyn qua c, ch c l(rnh) th n s chiu xuyn qua. Pha mt bn kiaca a c t mt cm bin thu. Vi cc tn hiu c hoc khng c nh sng chiuqua, ngi ta ghi nhn c n led c chiu qua l hay khng.

Gi strn a c n l, th mi ln cm bin thu nhn c n ln tn hiu n led th cngha l a quay c mt vng.

- u im: n gin, cch ly vi ngun iu khin ng c,- Nhc im: h thng hot ng thi gian di s b sai s tich luy h thng, mt s h

thng encoder tuyt i c gi thnh kh cao(encoder co do phn gii la 10 bit)

5.2 Cm bin chhng:Cc cm bin loi ny cho pht xc nh c gc hng hin ti ca robot so vi mt hngchun no . C 2 li chnh: cm bin la bn hoc cc cm bin nh v qun tnh (INS)

- Nguyn l hot ng:+ Vi loi cm bin la bn: xc nh gc lch ca robot so vi hng bc da vo hintng cm ng tu im : h thng n gin d ch tao,Nhc im: H thng c nhy tng dn theo cng ngh ch to, hay gp phi vn nhiu ttrng.+ Vi cc cm bin nh v INS: h thng INS gm c cc sensor cm bin vn tc gcv gia tc gc, cho php chng ta xc nh c vn tc gc nghing, gc chc, gchngu im: ca h thng ny l: nhy, chnh xc cao, tiu th cng sut nh, kich

thc nh, gi thnh r do s dng cc cm bin MEMS, v gic chnh xc cahng ban u khng ph thuc vo tc nhn bn ngoiNhc im:

Li v tr khi lp t cm bin: gy sai gc nghing, gc chi v gc hng lch (offset) ca cm bin gia tc: Li ra cm bin gia tc s b lch i mt gi tr

khng i. Gi tr ny li thay i mi khi tt / bt thit b.Hin tng lch v tri ca cm bin vn tc gc (do tc ng ca nhit ): Vt th


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khng chuyn ng nhng vn c vn tc gc khng iNhiu ngu nhin: Li ngu nhin trong o lng

5.3 Cm bin siu m pht hin vt th gn- Nguyn l hot ng: h thng gn 2 phn b pht v b thu tn hiu. B pht tn hiu

pht ra sng siu m sau mt thi gian t ta thu c song phn x t vt cn b thu tnhiu. Da vo khong thi gian t lc pht ti lc thu c tn hiu ta c thtnh ckhong cch n vt cn tnh theo nguyn l TOF d=v.t/2. Trong :- d l khong cch t vt cn n h thng- v l vn tc sng siu m trong mi trng truyn sng,

U IM: khong cch m cm bin c th pht hin ln ti 15mSng phn hi ca cm bin khng ph thuc vo bn cht ca b mt i tng hay tnhcht phn x sng ca i tng

Nhc im: cm bin siu m yu cu i tng c mt din tch b mt ti thiu. Sngphn hi cm bin nhn c c th chu nh hng ca sng m thanh tp m. Cm bintim cn siu m yu cu mt khong thi gian sau mi ln sng pht i sn sng nhnsng phn hi.kt qu cm bin tim cn siu m nhn chung chm hn cc cm bin khc

5.4 Cc loi cm bin hnh nh chnh

C hai loi b cm bin hnh nh chnh l b cm bin CCD v CMOS, CCD v CMOS lhai cng ngh khc nhau dng trong cc phn t nhy sng c s dng trong cc lnh vc xl hnh nh nh v tuyn truyn hnh, nhip nh s, cc my mc vn phng (scaners, copyers),thin vn, hng khng v tr, cng nh cc ngnh cng nghip khc.C CCD v CMOS u

thc hin mt nhim v ging nhau: bin cc tn hiu nh sng thnh cc tn hiu in t. Skhc nhau c bn ca chng (v nguyn l hot ng) nm cch chuyn cc tn hiu in t ra khi phn t nhy sng nhm mc ch x l tip v lu tr.

1. Nguyn l hot ng

Nhim v ca chip cm bin l bt nh sng khi ca trp c m v chuyn chng thnh ccin t; sau , cc in t ny c chuyn thnh in p; cui cng in p chuyn sang dngtn hiu s.

CCD gm mt mng li cc im bt sng c ph bng lp bc mu ( red, hoc xanh lcgreen, hoc xanh dng blue), mi im nh ch bt mt mu. Do , khi chp nh (ca trp

m), nh sng qua ng knh v c lu li trn b mt chp cm bin di dng cc im nh. Mi im nh c mt mc in p khc nhau s c chuyn n b phn c gi tr theo tnghng. Gi tr mi im nh s c khuch i v a vo b chuyn i tn hiu tng t sangtn hiu s, cui cng vo b x l ti hin hnh nh chp. Chnh qu trnh c thng tinthc hin theo tng hng lm cho tc x l nh chm, ri thiu hoc tha sng.

Cc nh nghin cu tnh n vic trang b thm b c nh b sung xen k vo cc im btsng c tt c cc thng tin im nh trong mt ln nhng iu ny bt buc phi tng khng


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gian ca chip cm bin, do vy m khng kh thi v mi mt. Chnh ci iu m cc nh nghincu mun b sung cho CCD th CMOS li c sn, bi cnh mi im bt sng c sn mchin b tr d dng tch hp ngay qu trnh x l im nh. Vi cu trc ny, mi im nh sc x l ngay ti ch v ng lot truyn tn hiu s v b x l ti hin hnh nh chpnn tc x l s nhanh hn rt nhiu.

Mt u im na m cu trc ny mang li l c th cung cp chc nng tng tc mt vngim nh (nh phng to mt phn nh) cho ngi s dng, iu m chp cm bin CCD kh lmc. Vi kh nng b tr nhiu nh vy nhng chip cm bin CMOS li tiu th t nng lnghn chip cm bin CCD, cng vi nhiu yu t khc m gi thnh sn xut chip CMOS thp.

th h u ca chp cm bin CMOS, nhiu to ra do vic khuch i im nh l ng k,lm cho nh chp c khng mn. im yu ny c ci thin th h sau bng vicc hai ln im nh (ln 1 c gi tr bt sng, ln 2 c gi tr ca mch b tr; sau thchin php tr) v bng vi thu knh lm nh sng ri vo ng v tr bt sng.

5.4.1

5 u im ca chip cm bin nh sngKhi so snh gia chip cm bin CCD v chip cm bin CMOS, ngi ta thng nu ra ngay 5 uim ca CMOS:

nhy sng cao, phn gii cao. in nng tiu th t, ko di thi gian dng pin. t b nhiu. Tc x l nh chp cc nhanh. Tch hp nhiu chc nng tng tc trn nh chp.

5.5

Cm bin o khong cc bng laserNguyn tc hot ng: o khong cch tmy o n mt vt no , my s pht mtxung laser, tia ny n vt cn s phn x trv, my o trang b b thu s nhn li xung ny.T my kim tra tlc pht n lc nhn mtbao lu v suy ra on ng i v v ca tiasng, sau chia hai xc nh c khong cch tht. Tt nhin my s lp trnh tnh tontt c. Ngi o ch vic bm nt v c kt qu trn mn hnh l bit c khong cch cn o.

- u im: h thng cho kt quc chnh xc cao, thi gian o nhanh,- Nhc im: Sng phn hi ca cm bin ph thuc vo bn cht ca b mt i tng

v tnh cht phn x anh sng ca i tng

Vd: thy tinh cho nh sng truyn thng qua nn h thng khng th pht hin c cc vttrong xut nh thy tinh, cc vt th hp th nh sng hay tn s nh sng.

6 Ti sao li phi s dng phng php tng hp cc cm bin trong dn

ng v nh vRobot di ng.(Cu ny Sinh bo tr li theo cu 5)


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7 nh ngha b chp hnh(actuator)? Ba loi b chp hnh c bn l g?

Cc cch btr cc bnh xe trong robot di ng, mch cu H l g

7.1 nh ngha b chp hnh.1. B chp hnh l mt dng ng c dng cho chuyn ng hoc iu khin mt c cu hoc mt

h thng chp hnh. N c vn hnh bi s dng mt ngun nng lng, thng l mt dng

ca dng in, thy lc, thy kh. Cc ngun nng lng ny sau s c bin i thnh mt

vi dng chuyn ng khc.

2. B chp hnh ging nh c bp ca robot, b phn chuyn i nng lng lu tr thnh

chuyn ng. Cho n by gi, ph bin nht l ng c in (lm quay bnh xe hay bnh rng)

v b chp hnh tuyn tnh m iu khin cc loi robot cng nghip trong nh my. Tuy nhin,

gn y c mt vi tin b i vi cc b chp hnh thay th khc m c cung cp nng lng

bi in, ha hc hay kh nn.

7.2

Ba B chp hnh c bn- Robot dng ngun cp in: Ngun in cp cho robot thng l DC iu khin ng c DC.

H thng dng ngun AC cng c chuyn i sang DC. Cc ng c s dng thng l ng

c bc, ng c DC servo, ng c AC servo. Robot loi ny c thit k gn, chy m, nh v

rt chnh xc.

- Robot dng ngun kh nn: H thng cn c trang b my nn, bnh cha kh v ng c ko

my nn. Robot loi ny thng c s dng trong cc ng dng c ti trng nh c tay my l

cc xy-lanh kh nn thc hin chuyn ng thng v chuyn ng quay. Do kh nn l lu cht

nn c nn robot loi ny thng s dng trong cc thao tc gp t khng cn chnh xc

cao.

- Robot sng ngun thu lc: Ngun thu lc s dng lu cht khng nn c l du p. H

thng cn trang b bm to p lc du. Tay my l cc xy - lanh thu lc chuyn ng thng

v quay ng c du. robot loi ny c s dng trong cc ng dng c ti trng ln.

7.3 Cch btr bnh xe trong robot di ng 3 cch b tr bnh xe

Mch cu

Bng cch s dng cc cng tc in trong mch cu H, ta c th thit lp chiu hot

ng cho ng c.


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B iu khin

8 B iu khin trong robot c nhim v g? Phn bit gia b iu

khin nhng v biu khin dng PCB iu khin s dng d liu t b cm bin tnh ton cc tn hiu iu khin cho b chp hnh v

thng l mt my tnh nhng.

8.1 Nhim v ca biu khin trong robot- ng vai tr nh l b no v c trng cho s thng minh ca robot.

- S dng d liu t b cm bin tnh ton cc tn hiu iu khin cho b chp hnh.

8.2 Phn bit biu khin nhng v biu khin dng PC-

B iu khin nhng l mt h thng my tnh nhng c thit k cho mt s chc nng iunhin c th bn trong mt h thng ln hn m thng c cc rng buc v tnh ton thi gian

thc. B iu khin c nhng nh l mt phn ca thit b hon chnh thng bao gm phn

cng v cc phn c kh. N thng s dng li x l{ l vi iu khin hay khi x l{ l{ tn hiu s

(DSP). Chnh v nhng c im , khi s dng b iu khin nhng, ngi thit k c th ti

u gim gi thnh, tng n nh v hiu nng ca sn phm m vn p ng c v mt

chc nng.

- B iu khin dng my tnh a dng nh l my tnh cc nhn PC th c thit k tr nn linh

hot v p ng c a phn nhu cu ca ngi dng cui.

9 Trnh by 4 khi (block) c bn trong dn ng robot di ng

(robot navigation). Nm r cc khi nim: Navigation, Localization

(hay Positioning), Perception, cognition, motion control, Path-

Planning, Global map. Local map, Map-Building.

Bn khi block dn ng cho robot di ng (Robot Navigation):


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Perception: Robot phi phn tch ccc d liu cn thit nhn c t sensorcm ng.

Localization: Robot phi xc nh c

v tr ca chng trong mi trng

Cognition: Robot phi quyt nh hnhng t c mc tiu.

Motion control: Robot phi iu chnh ng c t c quo nh mong mun.

Cc khi nim:

Navigation: L mt qu trnh gim st v iu khin chuyn ng ca phng tin t

mt hoc nhiu a im. Tt c cc k thut lin quan n nh v dn ng bao gm vtr ca hoa tiu so vi a im hoc m hnh c bit n.

Path planing: c hiu qu trong vic m rng vng hot ng cua robot. Path planing yu cu phi xc nh v tr hin ti ca robot v v tr ca mc tiu, chai uphi trong mt khung tham chiu hoc h ta .

Map building : xy dng bn c thdi hnh thc ca mt bn s liu hoc cck hiu m t v tr trong vng hot ng ca robot.

Map in this context denotes any one-to-one mapping of the world onto an internalrepresentation

10Phn bit gia bi ton ng hoc thun v ng hc ngc cho mt

robot di ng? Phn bit gia cc khi nim: khng gian lm vic

(work space), khng gian cu hnh (configuration space), h thng

Holonomic v Non-holonomic, ng i v quo?Bi ton ng hoc thun l bi ton t thng s ca c cu chp hnh (ng c) ta tnh ton ra

c ta ca robot. Bi ton ng hc ngc l bi ton m ta bit trc c quy lut chuyn

ng ca cc c cu chp hnh (ng c), ta phi tnh ton tt c cc thng siu khin cc ngc a robot t n im ch c ta cho trc.

Khng gian lm vic l tp hp tt c cc v tr m robot c tht ti. Mt cu hnh (bao gm cc thng

s ca robot) s miu t mt tnh trng ca robot. Khng gian cu hnh l tp hp tt c cc cu hnh m

robot c tht c. Khng gian lm vic ph thuc rt nhiu vo khng gian cu hnh.


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- H thng Holonomic l h thng m cc phng trnh ng hc c th biu din ch bng cc

hm hin (explicit function) ca cc gi tr v tr.

- H thng non-holonomic l h thng m cc phng trnh vi phn khng khtch cho n v tr

cui cng, v dnh trong 1 robot di ng non-holonomic cc thng s v khong cch chuyn

ng ca mi bnh khng tnh ton chnh xc v tr cui cng ca robot nh hnh v.

ng i (path) l qutch cc im m robot

di chuyn, n l mt miu t v chuyn

ng mang tnh cht a l thun ty. Cn qu

o (trajectory) l mt ng i m ngoi miu

t v a l, cn c thm miu t v thi gian

c c th ha vi cc bin nh vn tc v gia

tc ti mi im.

11Phn bit gia iu khin vng h (Open-loop Control) v iu khin

vng kn (Closed-loop Control) cho v d?iu khin vng h l iu khin ch s dng cc d liu u vo, h thng khng s dng phn

hi. iu khin vng kn l h thng iu khin ngoi cc d liu u vo m cn s dng phn hi t

iu chnh.

V d: iu khin vng h: ng c bc l mt ng c in 1 chiu m 1 vng quay ca n c chia

lm cc bc bng nhau. ng c bc c th nhn lnh quay hoc gigc quay no vi chnh

xc rt cao m ko cn bt c phn hi no.

Lnh Xung iu khin Dng ng c

iu khin vng kn: ng c servo l mt thit

b truyn ng quay cho php kim sot chnh

xc v tr gc. N bao gm mt ng c cng vi

mt b cm bin thng tin phn hi v tr thng

qua 1 gearbox. N cng i hi mt b iu

khin tng i phc tp, thng l mt mch

iu khin chuyn dng thit kc bit s

dng vi ng c servo. Tn hiu ra ca ng c

c ni vi mt mch iu khin. Khi ng c

Giao din

ngi dng

Ch s Biu

khin

ng c


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quay, vn tc v v tr sc hi tip v mch iu khin ny. Nu c bt kzl{ do no ngn cn chuyn

ng quay ca ng c, c cu hi tip s nhn thy tn hiu ra cha t c v tr mong mun.

Mch iu khin tip tc chnh sai lch cho ng c t c im chnh xc.

12nh v cho robot di ng l g? Vai tr quan trng ca n vi mtrobotdi ng thng minh (t qun tr)?

12.1 - nh vcho robot di ng l g:Khi robot mun i t vtr A n v tr B, robot phi bit mnh ang ng v tr no.

iu l rt quan trng robot c th tiu khin mnh ti c v tr mong mun. nh v

cho robot di ng l xc nh vtr ang ng ca robot, hng , ta , hay v tri so vi mt mc no

thng l im mc ban u.

12.2Vai tr quan trng ca n vi mt robot di ng thng minh (t qun

tr):Vi mt robot di ng thng minh, vic xc

nh v tr ca robot rt quang trng, ging

nh con ngi, nu khng bit mnh ang

ng u, vtr no th chng ta b lc.

robot cng vy. Vi con ngi, vic xc

nh v tr cn ti nhng gic quan, th vi

robot, xc nh c v tr n dng

nhng cm bin, cm bin chhng (con

quay hi chuyn, cm bin la bn, IMU),gii m trc quay hay s dng nh vi ton

cu GPS

Hnh bn l s ca robot xc nh v

tr.

13Cc php o vtr tng i v tuyt i? u nhc im?

13.1Cc php o tngi: ( ni lun uu nhuoc im)+ Gii m trc quang: thng l mt a trn quay quanh trc, trn a c cc rnh v c cn n led v

cc cm bin anh sng thu nhn tn hiu. T tnh ton ra v tri, phng php ny n gin v

khng tn km tuy nhin b sai stch ly.

+ n ng qu tnh: phng php ny s dng con quay hi chuyn v mt strng hp s dng

thm cm bin gia tc k. xc hng. tuy nhin cm bin con quay hi chuyn th b tri theo thi


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gian nn gy ra s khng chnh xc. Tuy nhin vic s dng kt hp vi cc cm bin khc th n s rt

chnh xc tuy nhin gi thnh khng r.

13.2Cc pht o tuyt i:+ Active Beacons: Phng php ny tnh ton v tr tuyt i, da vo 3 v tr mc hoc nhiu hn cc

ct pht tnh hiu (trm thu pht GPS ang { m ko bit dim dt thno),

+ Artificial landmark recongnition( cai nay going ngon hai dang nhe @@) phng php ny s dng cc

ct mc xc nh vtr trn mi trng. N c u im ti u vi nhiu iu khin mi trng v sai

s b gii hn, Ging nh mt hot ng tch cc, n a ra v tr don., Tuy nhin vic nht ra ct

mc v sa li v tr trong thi gian thc khng thlun lun c thc hin.

+ Natural landmark recognition: l mt ct mc c cng nhn, n l mt mc c bit ngoi mi

trn, n l mt mc c sn, n phi ni tri hn so vi mi trng, v tin cy ca phng php ny

khng cao so vi mc c do con ngi to ra. (c ngha l mc ny da vo mt mc c bit ca mi

trng)

+ Model matching (mo hinh kt hp) da vo thng tin thu thp c t cc cm bin v so snh vi

bn hay m hnh ca mi trng, nu cc tnh nng gi tr ca cm bin ph hn vi bn , m

hnh th sau v tr tuyt i ca robot c thc c tnh. inh vthng bao gm cc bn ton

cc da vo cc cm bin quan st trong mi trng,v tch hp thm cc bn bao gm khc v tri

cha c bit n. bn dn ng c chia lm 2 loi chnh: geometric (hinh hoc) maps v

topological maps.

14nh v bng nh x bn (Map-based Positioning)? Hiu v 2 cch

biu din bn (Geometric Map v Topological Map)?nh v bng nh x bn l mt phng php m robot s dng sensor to mt bn ca

mi trng cc b. Sau bn ny c so snh vi bn ton cc m c lu trong b nh.

Nu ging nhau th sau robot tnh vtr v hng. Bn c lu trc c th l mt m hnh

CAD hoc n c thc to nn t d liu ca sensor trc . Cc th tc trong nh b bng nh x

bn c th hin trong hnh v:


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12 | P a g e

Nhng thun li ca nh v bng phng php nh x bn :

- Phng php ny s dng nhng g xy ra ca mt mi trng bn trong suy ra thng tin v

tr m khng cn thay i mi trng.

- Phng php ny c th dng cp nht bn .

- Phng php ny cho php mt robot lm quen vi mt mi trng mi v nng cao s chnhxc.

Nhng bt li ca phng php nh v bng nh x bn :

- Cn c im chun, nhng c im d phn bit s dng cho so snh.

- Bn cn chnh xc.

- Cn c sn mt khi lng ln nng lng cho cm ng v x l.

14.1Map bulding

14.1.1Map buildingC hai cch c bn trong nh v bng nh x bn l c sn mt bn hoc l robot phi t to

nn bn ca mi trng. Hoppen lit k ra 3 bc chnh ca x l d liu sensor cho vic to bn

l:

- Lc ra nhng im c trng ca d liu t sensor

- S lin kt d liu t nhiu sensor

- T to mt m hnh ca mi trng vi nhng mc tru tng khc nhau.

Mt vn lin quan n xy dng bn l autonomous exploration. to nn bn , robot

phi khm ph mi trng ni cc vng biu . Gi s robot bt u cucj hnh trnh m khng

bit g vmi trng. Khi cn mt phng php chuyn ng ti a slng vng biu trongmt lng thi gian t nht.

14.1.2Xy dng bn v lin kt sensor

Vic kt ni cc d liu t nhng sensor khc nhau l rt cn thit qu trnh ny gi l lin kt sensor.

14.1.3Map Matching

Vic kt ni bn thng tp trung vo vn kt ni mt nh gm vtr v hng vi m

hnh. Thng thng, vic kt ni ny thnh cng bng cch lc ra nhng c im xc nh stng

ng ga nh v c im ca m hnh.

Cc thut ton matching c th chia ra thnh hai cch: icon-based v feature-based.

14.2Geometric and Topological Maps

Trong nh v bng nh x bn c hai cch biu din thng thng l: bn hnh hc v bn

hnh hc topo. Mt bn hnh hc biu din cc vt theo mi quan h hnh hc. N c th l mt

bn k Trong nh v bng nh x bn , nhng bn hnh hc c suy ra t sensor phi

c ni vi bn ton cc ca mt vng rng. Thng vic ny gp kh khn v li v v tr ca robot.


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13 | P a g e

Mt khc hng tip cn ca hnh hc tp da trn s lin h gia hnh hc v nhng c im c

nhn bit ch khng phi l v tr. Kt qu biu din l biu m cc node biu din nhng c im

nhn bit c v cc cnh biu din mi quan h gia cc c im. Khng ging nh bn hnh hc,

bn topo c thc dng v duy tr m khng cn tnh vtr robot. iu ny c ngha l l i trong

cch biu din nay sc lp vi li trong tnh ton v tr ca robot.

14.2.1Geometric maps for Navigation

C nhiu cch biu din d liu bn hnh hc, c lcch n gin nht l bn hnh .

Thun li ca bn da trn cc trng l:

- Cho php mt ln hn cc bn ni

- t tnh ton v c th to nhanh

- D tch hp cc thng tin t cc sensor khc nhau

- C th s dng biu din d liu mt cch chnh

Bt li:

- C nhng vng bt nh ln.

- Gp kh khn trong vic kt hp vi nhng active sensor

- Cn mt qu trnh nh tnh phc tp cho robot

14.2.2Topological maps for navigation

Nhn nh a im: vi chc nng ny, v tr hin ti ca robot trong mi trng c xc nh.

Thng thng, mt m t ca v tr hay ca node trong bn c lu tr cng vi a im. M t

ny c th abstract hay n c th l mt bn sensor cc b. mi node, matching gia d liu cm

nhn c v m t ca node.

La chn hnh trnh: Vi chc nng ny, mt ng ta im hin ti ti im ch c tm ra.

15nh v da trn cc ct mc (landmarks hay beacons)

15.1Landmarks-based Positioning

Ct mc l nhng vt thng trong mi trng m c thnh v chnh xc khi chng trong

tm nhn ca robot. Robot s dng nhng ct mc nh vthng l nhng ct mc nhn to m

c t sn bi nh thit k. H thng iu khin cho nh v da trn ct mc gm hai bc ri rc.

Khi ct mc trong tm nhn, robot nh v nhanh v chnh xc, nhng khi khng trong vng ct mcrobot nh v khng chc chn n khi gp c ct mc tip theo. Vic chuyn tip t vng ct mc

ny sang vng ct mc khc robot phi lu { ti bn cn thn, vic chuyn i cn ngn, c th

nh v thnh cng khi ti ct mc ktip.

Ct mc l nhng c im d phn bit m robot c th nht bit t li vo sensor. Ct mc c

th l hnh hc hoc bao gm nhng thong tin khc. Thng, ct mc c v tr cnh robot c th

nh v chnh n. Ct mc c chn d xc nhn. Trc khi robot s dng ct mc nh hng


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14 | P a g e

th nhng c im ca ct mc cn c bit trc v lu trong b nh ca robot. Nhim v quan

trng sau l nhn bit ct mc v tnh ton v tr ca robot. n gin ha, vn thng c gi

s rng v tr hin ti v hng ca robot c bit sn v throbot ch cn tm kim ct mc trong mt

vng gii hn. Quy trnh nh v da trn ct mc nh hnh:

Ct mc t nhin l nhng vt, dc im m c trong mi trng v c chc nng ca n ch khng

phi ch cho robot nh v. Ct mc nhn to l nhng vt c thit kt trong mi trng vs

mc ch cho robot nh v.

im bt tin ca nh v da trn ct mc l n yu cu sthay i mi trng. N cn mt slng

ct mc ln bao ph ht din tch nh my ln hay phng th nghim.

Tm li nhng c im ca vic nh v da trn ct mc:

- Ct mc tnhin a ra s linh hot v khng cn thay i mi trng.

- Ct mc nhn to t, v cn c thm thng tin c m ha.

- Khong cch ln nht gia robot v ct mc (landmark) thng ngn hn trong h thng ct

mc (beacon) tch cc.

- Snh v chnh xc da vo khong cch v gc gia robot v ct mc

- X l nhiu hn trong h thng ct mc tch cc (active beacon system)

- Nhng iu kin bn ngoi nh nh sng cng l mt vn .

- Ct mc cn c sn trong mi trng xung quanh robot

- nh v bng ct mc yu cu robot bit v tr hin ti tm kim ct mc nu khng s mtthm thi gian x l v tm kim.

- Cn c c s d liu v ct mc v v tr.

15.2Beacon based position.

Mt trong nhng gii php cho vn nh v l thit k v dn dng mt h thng ct mc

active cho mi trng. y l phng php c s dng cho c nhng ng dng cng nghip v qun

s vi chnh xc cao. Trong phn ln cc h thng beacon, thit kph thuc u tin vo cc l

thuyt hnh hc nh hng n vic nh v. Trong thng hp ny robot phi bit v tr ca hai active

ultrasonic beacon trong ta global nh v chnh n.


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15 | P a g e

16Cc thch thc gp phi trong qu trnh nh v (sensor noise and

alising noise, effector noise)?

16.1Nhiu do cm binCm bin l mt u vo c bn trong qu trnh nhn thc ca robot. Tuy nhin, cm bin cng

tn ti mt gii hn nht nh vthang o cng nh cc can nhiu xy ra trong qu trnh o c:

- Khi mi trng c nhng thay i, khng nm trong phm vi v khnng o ca cm bin nn

b cm bin b qua

- nh hng t robot, thit bkhc vo mi trng lm ri lon hot ng ca cm bin

- u o ca cm bin khng cn nhy hoc lm bn, che m mt

C th thy can nhiu do cm bin hu nh khng th trnh khi, tuy nhin ta cng c nhiu cch

khc phc iu ny bng cch xc nh li phm vi o v i tng o i vi tng mi trng quanh

robot hoc s dng nhiu cm bin cng loi gim thiu xc sut sai s so vi vic ch c mt cm

bin lm vic.

16.2Nhiu sai sCc h thng nhn bit ca robot ch lm vic vi cc tn hiu li vo thch hp vi tng loi mi

trng nht nh. V th, khi a robot n mt loi mi trng khc, h thng nh v ca n s tht

bi hon ton do phi nhn nhng thng tin o c sai t mt mi trng l gi ti. Trong robot, nhiu

sai sl hon ton bnh thng v khng th trnh khi. Do vi cc robot ta thng dng nhiu

loi cm bin khc nhau thu thp c nhiu thng tin khc nhau tmi trng, qua xy dng li

bn phc vcho qu trnh nh v.

16.3Nhiu tc ngDo tn ti nhiu cm bin v nhiu sai s nn hnh thnh nhiu tc ng: khi mt hnh ng c

robot thc thi, n c th cho nhiu kt qu khc nhau do chu snh hng t thng s sai lch gy ra

bi nhiu cm bin v nhiu sai s. K ckhi bit trc c v tr ban u ca mnh th v tr tip

theo ca cng s c khc bit so vi tnh ton. S sai lch trong chuyn ng lin quan n s sai

lch trong qu trnh o c hoc khnng tnh ton km ca robot khi khng s dng c cc thng

tin vng hc v ng lc hc; hoc do thay i ca yu tmi trng. Trong qu trnh chuyn ng

v nh v (da v cm bin bnh xe v cm bin heading ch bit dng t g cho thun), v tr ca

robot c thc tnh ton nh vic m ha vng quay bnh xe hoc t s liu o c bi heading

sensor hoc chai. Do , s sai lch tqu trnh o c ny stch ly theo thi gian dn n v tr

robot cng sai lch tch ly theo thi gian. Di y l mt s nguyn nhn ca li odometric:

- Hn chphn gii khi tch hp

- Cc bnh xe khng thng hng

- ng knh bnh xe c sai lch

- Li im tip xc ca bnh xe

- Tng tc vi b mt khng ng u (trt, mt phng g gh)


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16 | P a g e

Mt s li c thxc nh v loi bc bng cch hiu chnh li h thng. Tuy nhin vn cn c rt

nhiu li bt nh (ngu nhin) kh c th loi bc. Ta c th phn loi nhng li ny da trn quan

im hnh hc thnh ba nhm chnh sau:

- Li phm vi: tch ly khong cch trong qu trnh chuyn ng ca robot (bng tng ca s di

chuyn cc bnh xe)- Li chuyn hng: tng tnh li phm vi, nhng xy ra khi robot chuyn hng (gy ra do

s sai khc tc gia cc bnh xe)

- Li trt: gy ra bi sai khc trong li ca cc bnh xe dn n li ca gc nh hng robot

n mt khong thi gian di, li chuyn hng v li trt vt xa li phm vi, khi tng hp

ng gp li ca chng s tr ln phi tuyn. Hy xem xt mt robot c vtr ban u xc nh ang c {

nh di chuyn thng theo mt trc ta . Tuy nhin, li tt v chuyn hng hnh thnh mt gc

lch . Cng ngy gc lch ny cng ln khin robot di chuyn xa khi khung ban u. y chnh l mt

v d v Nhiu tc ng nh hng n robot khi cc li c tch ly theo thi gian

17Trnh by bi ton xc lp m hnh tnh sai s cho vic c lng v

tr (x,y,0) cho mt robot vi cc bnh xe vi sai, bng phng php

Odometry? Phn bit u l cc thng s h thng? u l cc thng

stc ng vo? Thng so? Cc can nhiu?(Phn ny c qua ton cng thc, vi chm y t cng chng hc hnh ghi chp g, thi th cdch y

nguyn li slide cho cc bn tham kho bn no mun c bn gc th tm slide th2 trang 53-64)

V tr ca mt robot c biu din di dng vector

[

]

Vi mt robot vi sai, vtr c c lng bi qu trnh tch ly chuyn ng bt u t mt v tr xc

nh. Xt mt h thng ri rc vi mt khong cch ly mu t cnh, khong cch dch chuyn ph

tri (x; y; ) l:

Trong :

(x; y; ) = qung ng dch chuyn trong khong ly mu cui cng


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17 | P a g e

= khong cch dch chuyn ca bnh phi v bnh trib = khong cch gia 2 bnh

T ta c v tr cp nht mi p:

Thay (3.4) (3.5) vo (3.6) ta c:

Phng php odometric c lng mt v tr cp nht rt st vi v tr tht. Tch ly li cc gi tr bt

nh ca p v cc li chuyn ng trong qu trnh tng chuyn ng ( ) khin cho li v tr tch lytng theo thi gian.

Tip theo, chng ta thit lp mt mu li cho vtr tch ly p thu c ma trn hip phng sai ca qu trnh c lng v tr odometric. Ta gi s rng, ti im xut pht, gi trban u ca ma trn

hip phng bit ttrc. Vi gia tng chuyn ng ( ) ta gi s c ma trn hip phng sai sau:

Trong l khong cch dch chuyn bi mi bnh v kr, kl l cc hng s li biu din ccthng skhng xc nh ca motor li v tng tc gia bnh vi sn. Trong cng thc (3.8) chng ta

tha nhn:

Sai lch bnh xe do bnh phi v bnh tri c lp gy ln


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18 | P a g e

Phng sai ca li (gy bi bnh phi v tri) t l vi gi tr tuyt i ca khong cch dch chuyn

( )Li chuyn ng (motion errors) hnh thnh do sai lch bi bin dng ca bnh xe, trt, bng

phng ca sn, li do encoder,. Gi tr ca hng s li kr v kl ph thuc vo mi trng v robot v

hon ton c th thit lp bng thc thi v phn tch chuyn ng

Nu ta gi s rng p v = ( ) khng tng quan ln nhau v o hm f (phng trnh 3.7)c tnh xp x bng cng thc Taylor bc nht nh sau:

Ma trn hip phng sai lun lun c cho bi ma trn ca ln tnh trc v c thc tnhsau khi xc nh gi trban u

S dng phng trnh (3.7) pht trin 2 Jacobians Fp v F


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19 | P a g e

Sgia tng tnh bt nh ca

v tr trong qu trnh di

chuyn theo ng thng:

Ch rng tnh bt nh ca

trc tung (y) tng nhanh hn

trc honh (hng cachuyn ng). y l kt

qu ca vic tch ly tnh bt

nh ca nh hng robot.

Cc hnh e-lip v xung quanh

v tr robot th hin tnh bt nh theo trc x,y. S bt nh ca gc khng c biu din trong hnh tuy

nhin ta hon ton c thxc nh mt cch gin tip nh sau:

Ta c phng trnh (3.11)

Stng ca tnh bt nh v tr theo s di

chuyn vng (r l hng s). Ln na, tnh

bt nh ca trc tung li tng nhanh hn

trc honh. Ch rng trc chnh ca cc

e-lip bt nh khng cn vung gc vi

hng ca chuyn ng na.

Tm li:(phn ny l kin ch quan, mong mi ngi gp thm)

Thng s h thng gm: p(x, y, ), direction, speed, b

Thng stc ng vo: kr, kl

Thng so: t

Cc can nhiu: x, y, Sr, Sl,


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20 | P a g e

18M tbi ton nh v da trn nh x bn bng phng php xc

xut vi b lc Kalman (Probabilistic Map-based localization with

Kalman Filter) trong trng hp c lng tnh (static estimation)?

Phn bit cc khi nim v tr thc, vtr o c, vi vtr c lng

c.Tr li:

5 bc ca phng php nh x bn :

Trong : Prediction (don) da trn estimate (c lng) trc v phng php odometry.

Trong bc u tin, v tr ca robot thi im k+1 sc don bi vtr c ca n(thi im k) v s chuyn ng ca n da theo ma trn iu khin u(k).

Observation (quan st) da trn cc sensor.bc th 2, robot phi quan st v tr mi ca n bng cc sensors gn trn .

Measurement prediction da trn prediction (don) v bn .Bc tip theo, ta s dng v tr c d bo ca robot v bn to ra cc don quan st .

Matching (nh x) cc quan st vo bn .Phn chia cc quan st (h sc gn bi sensors) vo ch (c lu trongbn ).

Estimation (c lng): cp nht v tr.p dng b lc Kalman vi php c lng tnh.


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21 | P a g e

Phn bit cc khi nim: V tr thc: v tr ca robot trong khng gian.

Vtr o c: vtr c cho l v tr thc qua cc php o s dng sensors.

V tr c lng c: v tr robot c cho l v tr thc sau khi kt hp cc php obng sensors v phng php odometry.

19Hiu th no v bn cht vai tr ca b lc Kalman trong vic tng

hp cc cm bin? Ti sao nh b lc Kalman m c lng v tr ca

robot trnn chnh xc hnRobot da vo cc cm bin xc nh v tr ca mnh. Vi mi cm bin, robot c th

xc nh c mt xc sut v v tr ca n trong khng gian (do cm bin lun c nhiu), B lcKalman l mt thut ton lc nhiu ra khi thng tin. N tng hp cc xc sut v tr ca robot,thu c qua cc cm bin a ra c mt xc sut c lng. Xc sut c lng ny lun

gn vi v tr thc hn xc sut thu c qua tng cm bin n l.Cc cm bin lun tn ti nhiu. Nhiu tng loi cm bin khc nhau l khc nhau.

ng thi, cc cm bin cng c th nhy vi cc vt cn khc nhau. Bng cch tng hp thngtin t cc cm bin, b lc Kalman lun a ra c gi trc lng chnh xc hn so vi gitrthu c ca tng cm bin n l.

20Ti sao li phi dng b lc Kalman m rngB lc Kalman l mt b lc tuyn tnh nn c th p dng cho cc h thng tuyn tnh.

Khng may l trn thc t h thng tuyn tnh khng tn ti, tt c cc h thng u l h thng

phi tuyn. B lc Kalman tuyn tnh ha l gii php cho vn trn. Tuy nhin, p dngc b lc Kalman tuyn tnh ha, chng ta cn phi c nominal trajectory (qu o danh

nh) trc khi c lng. Vi mt s h thng, chng ta c th bit trc c qu o danhnh (v dnh , mt chuyn my bay vi lch trnh nh hay l chuyn ng ca tay mytrong mi trng cng nghip), nhng cho cc h thng khc, chng ta c th khng c cch no bit trc c qu o danh nh. V vy chng ta cn phi dung b lc Kalman mrng chonhng trng hp ny. Cch m b lc Kalman mrng gii quyt vn l s dng chnh gitrc lng x ca chng ta lm qu o danh nh trong b lc Kalman tuyn tnh ha. Ni

cch khc, trong b lc tuyn tnh ha chng ta thay bng y l mt cch kho lo

thc hin vic c lng: chng ta s dng mt qu o danh nh c lng x, sau li sdng gi trc lng ca x nh l qu o danh nh.


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22 | P a g e

21Phn bit bn cht khc nhau gia cc bi ton vch ng i v

trnh va chmBi ton vch ng i: bn cht l bi ton vch ng ton cc: Mc tiu l tm ra mt

con ng trong khng gian vt l t mt a im ban u ti ch v trnh mi va chm vi

vt c. (tc l bn thn n cng cha bi ton trnh va chm). iu kin gii c bi tonny l chng ta cn phi c mt bn tt vmi trng xung quanh dnh cho vic dndng. C th l bn hnh hc hoc bn metric hoc kt hp c hai.

Bi ton trnh vt cn: bn cht l bi ton vch ng cc b: Mc ch l trnh vachm vi cc vt cn da trn cc thng tin c c t cc sensor thi gian thc. N thngda trn bn cc b. Tuy nhin bi ton trnh vt cn nn c ti u ha vi s ch timc ch chung, tc thc tv ng hc ca robot, cc sensor, nguy c va chm thc t vtrong tng lai.

22Trnh by phng php trng th c bn (khi nim trng th,

xy dng th ht, thy)?Phng php trng thc bn to nn 1 trng th, hoc 1 dc, ngang qua bn ca robot

dn robot ti ch t nhiu vtr khc nhau. Phng php trng thlm robot ging nh 1 qu bng

ln xung 1 qui. ch (1 im nh nht trong khng gian ny) ging nh 1 lc ht v nhng vt cn

th c coi nh nhng nh ni hoc l lc y. Tt c cc lc ny u tc dng ln robot; trong TH ny

robot lun c coi l 1 cht im trong khng gian. Robot si n ch trong khi trnh nhng chng

ngi vt bit trc.

Gi s robot c thnh vc v tr ca n cng vi bn v trng th, n c th lun lun xc

nh c hot ng tip theo da vo mi trng m n ang di chuyn. tng ng sau phng php

trng thny l robot c ht bi ch, trong khi n cng by bi cc chng ngi vt c

bit trc. Nu chng ngi vt mi xut hin trong sut qu trnh dch chuyn ca robot, n c th

update trng th tch hp them nhng thi tin mi ny. Trong TH c bn nht, ta coi robot nh 1

im, v vy, hng c th bqua v trng thc thcoi nh 2D (x,y).

Gi s c hm kh vi U(q), ta c thtm c lc gi F(q), v tr (x,y):

vi,

Trng thtrn robot c thc tnh:

Tng t vi lc thtrn robot:


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23 | P a g e

Lc ht. Mt lc ht c thc nh ngha n 1 hm parabol:

Trng ht l kh vi, dn ti lc ht Fatt :

Hi t v 0 khi robot vch.\

Tng t vi lc tc ng ln robot c th c 2 thnh phn l lc ht v y:

Trng thy. Trng thny to ra lc y vi robot t nhng vt cn bit trc. Thy cn rt

mnh khi robot gn vi vt th, nhg khng tc ng khi n xa. Mt v d vi lc y:

Lc y:

Kt qu lc F(q)=Fatt(q)+Frep(q) tc ng ln robot gip robot i n ch m ko chm phi vt cn.

23Trnh by phng php tm kim ng i bng th? Trnh by 3cu trc th ph bin (Visibility Graph, Voronoi Diagram v Cell

Decomposition)- Gim gi thnh v mc ti thiu i vi vn tm ng gia hai vtr xc nh trn bn

.

- Cu trc bn l mt hnh dng tng trng.

- Khng gian trng thi nm trong mt khu vc c nh du.


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24 | P a g e

- Tn ti mt s khu vc cha c nh v trn bn .

23.1Ba cu trc th ph bin

23.1.1Visibility Graph (1/2)( th r rng)Cc nt trn bn l im khi u v im ch n, cc cu hnh vng cung l cc chng ngi vt.

Tt ccc nt c nh vn cc im khc v c kt ni vi nhau thnh cc on, khc c

gi l ng i trn bn (n ging nh mp, g)

Vic s dng th ny ph hp vi khu vc c chng ngi vt gm nhiu cnh.

- di ng i ngn nht

- Trnh vt cn trnh va chm

- S nt v cnh tng tng ng vi s vt c

cnh

- N kh c kh nng hot ng tt trong mitrng ng c, nhiu vt cn.

Cu trc bn loi ny thng c p dng trn cc

robot di ng v vic thc thi kh n gin. Cu trc bn

r rang ny cng c th thc hin vi khng gian lien

tc hoc ri rc. Hai vn quan trng khi thc hin tm

kim trn th r rang ny:

- Th nht, kch thc khng gian v s cnh, s nt tng t l thun vi s vt cn. Phng php

s dng c tht hiu qu tt ty thuc vo mi trng cng nh cng nghc dng

thc hin th.

- Vn th hai l c th thc hin vic d ng cho robot trong hang ng. C th chng minh

phng php thr rang l phng php ti u tm c con ng ngn nht. Gii php

thng thng l pht trin cc vt cn nm ngoi bn knh hot ng cu robot, thay i

phng hng ngay khi xc nh c khong cch trobot n vt cn.

23.1.2Voronoi Diagram (Phng php khi Voronoi)Wiki- l mt cch phn tch mt khng gian mtric

theo khong cch ti mt tp hp ri rc cc vt th cho trctrong khng gian. Tp hp cc vt th c th l tp hp ri rc

ccim.Trong trng hp n gin nht, khi cc vt th lcc im, ta c mt tp hp S gm cc im trn mt phng,c gi l cc im Voronoi. Mi im sng vi mt Voronoi, hay cn gi l Dirichlet, k hiu l V(s), bao gm ttccc im gn shn tt ccc im Voronoi khc. Cc cnhca s Voronoi l tp cc im c khong cch ti hai imVoronoi gn nht l nh nhau. Cc nh ca s Voronoi lcc im c khong cch ti t nht ba im Voronoi gn nht lnh nhau.
http://vi.wikipedia.org/wiki/Kh%C3%B4ng_gian_m%C3%AAtrichttp://vi.wikipedia.org/wiki/Kh%C3%B4ng_gian_m%C3%AAtrichttp://vi.wikipedia.org/wiki/Kho%E1%BA%A3ng_c%C3%A1chhttp://vi.wikipedia.org/wiki/Kho%E1%BA%A3ng_c%C3%A1chhttp://vi.wikipedia.org/wiki/Kho%E1%BA%A3ng_c%C3%A1chhttp://vi.wikipedia.org/wiki/%C4%90i%E1%BB%83mhttp://vi.wikipedia.org/wiki/%C4%90i%E1%BB%83mhttp://vi.wikipedia.org/wiki/%C4%90i%E1%BB%83mhttp://vi.wikipedia.org/wiki/%C4%90i%E1%BB%83mhttp://vi.wikipedia.org/wiki/Kho%E1%BA%A3ng_c%C3%A1chhttp://vi.wikipedia.org/wiki/Kh%C3%B4ng_gian_m%C3%AAtric


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Khi Voronoi l tp hp cc ng cha cc im cch u hai (hoc nhiu hn) vt cn. imbt u v im kt thc c xc nhn trn bn , mi ng v di m khong cch t nng bao ca vt cn tng nhanh nht. Khong cch di chuyn trn khi Voronoi cng c chn la khong cch n cc ng bao l ln nht.i vi mi im bt k trn vng khng gian t do, mytnh c thxc nh khong cch tim n vt cn gn nht. Phng php tm ng trong khiVoronoi cng tng tnh phng php xc nh ta chnh xc (Visibility graph) v lun tn ti vng

khng gian robot c th di chuyn gia cc vt cn.

Nhc im ca phng php ny l b gii hn di hot ng ca sesor

23.1.3Cell Decomposition (Phn tch) (slide cui

trang 32)

Bao gm cc vng c th di chuyn n gin, c kt ni

vi nhau thnh cc cell

Cc cell nh kt ni vi nhau thnh s

Cc cell c xy dng da trn cc cnh ca vt cn v lyphn gp khc lm im u im cui mi cnh. Mi

cell c th tip gip vi mt vi cell khc. ng i ni gia

cc cell. Qung ng ngn nht l qung ng tim

bt u n im kt thc m i qua t cell nht

23.2Phng php d ngPhng php d ng gm:

- Breath First: Duyt grapth tnh, xt cacds nh k cng gn cng tt v cho vo danh sch v(dng queue)

- Depth First: Duyt Grapth tnh u, xt cc nh k vi n v cho vo danh sch v (nh du

duyt ri) v mi ln i nh thth cng xa nh u cng tt.(dng stack)

- Dijkstra

- A* and variants: tm kim mt ng i t mt nt khi du cho ti mt nt ch cho trc

(hoc mt nt tha mn mt iu kin din tch). Thut ton ny s dng mt nh gi

heuristic xp loi tng nt theo c lng v tuyn ng tt nht i qua nt . A* lu

tr mt tp cc li gii cha hon chnh, ngha l cc ng i qua th, bt u t nt xut

pht. Tp li gii ny c lu trong mt hng i u tin. Th tu tin gn cho mt ng i x

c quyt nh bi hm: f(x) = g(x) + h(x). trong g(x) l chi ph ca ng i cho n thiim hin ti (tng trng s cc cnh i qua). H(x) l hm nh gi heuristic v chi ph nh

nht n ch t x. Hm f(x) cng thp th u tin x cng cao

- D* and variant: L mt thut ton gii quyt bi ton ng i ngn nht ngun n trong mt

thc hng khng c cnh mang trng s m.

Cho mt thc hng G=(V,E), mt hm trng s w: E-> [0,~) v mt nh ngun s. Cn tnh

ton c ng i ngn nht tnh ngun s n mi nh ca th.

hệ thống robot thông minh (1)

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