Position Control of Robotino Mobile Robot Using Fuzzy Logic

Transcription

1 Posiion Conol of oboino Mobile obo Using Fuzz Logic S. E. Olean, M. Dulău,. Puskas Peu Maio Uniesi of Tg. Mues, S.C. Maqua Schalsseme S.C.S. Sibiu, Absac-The appeaance of fuzz logic heo le o ne ens in oboics fiel an soles aious pical poblems. In fac, fuzz logic is a goo alenaie fo inceasing he capabiliies of auonomous mobile obos in an unknon namic enionmen b inegaing human epeience. The pape pesens he esign an implemenaion of he posiion conol using fuzz logic fo an omni iecional mobile obo. The posiion conol of he mobile obo as ese emoel using he Feso oboino plafom an Malab enionmen. The obsacle aoiance an mobile obo oome ee also suie in his ok. I. INTODUCTION Since he fis inusial obo began is ok a he Fo facoies in 959, eseach in obo echnolog has been pefome inensiel. A he beginning he obos eplace some emploees inole in jobs ih epeiie asks laing he founaion aea of inusial obos. Lae on, he ele-opeaion pemue he human conol of he obos an he iesificaion of he asks. No, ue o he echnological pogess he oboics fiel coes no onl he inusial applicaions bu also a ie ange of ohes puposes. Thus, aance obos ge inceasingl auonomous skills o be able o paicipae in ee human life. Auonomous obos ae use in aious aeas like Inus, Seice an cae, Agiculue, an Hospials, hee he aance obos ae ealing ih a namic human enionmen, hich equie human ineacion an eacion o signals, namel a high egee of auomaion. B compaison, inusial obos ae use in saic an knon enionmen. The high egee of auomaion an auonom of obos is obaine b he inesecion of eseach fom aious fiels such as social sciences, aificial inelligence, oboics, auomaion, compue science []. A ne sep in he fiel of oboics ealing ih unceainies an human enionmen as he inoucion of fuzz logic. Noaas of fuzz logic is use in aious fiels, bu in case of mobile obos i soles some pical poblems [,]: - auonomous naigaion; - behaioal conol; - spee conol; - map ceaion in unknon enionmens; - acking of naual feaues in obo s enionmen; - ision-base naigaion. Of couse, he inesecion beeen he fiel of fuzz logic an mobile oboics is becoming moe eien. Fuhemoe, mos epoe esigns el on inelligen conol appoaches such as fuzz logic conol an neual neoks [5, 6]. In he auonomous mobile obos asks he accuae localizaion is a ke peequisie fo successful naigaion in lage scale enionmens, paiculal hen global moels ae use, such as maps, CAD moels, aings, an opological escipions. Fo he self-localizaion of he mobile obo a lage ange senso ih supeio pefomance is neee, eg scanning lase ange fine eelope fo oboics applicaions. Fo he epeimenal sage e ha he Feso oboino Plafom ihou such a senso. So, e esigne a fuzz logic posiion conol of a mobile obo using jus he opical shaf encoes an infae isance sensos fo he measuemens. Afe implemenaion of he algoihm in he Malab language, ou obo ill be able o pefom posiioning asks in a namic human enionmen een in he pesence of obsacles. Fo he implemenaion of he algoihm e use also he oboino Malab Toolbo. Fig. shos he es enionmen, in hich he obo is o be funcioning. The enionmen consiss of a single oom ih knon geomeic imensions. Figue. Illusaion of he es enionmen. In he ne secions of he pape e pesen a sho escipion of he Feso oboino mobile obo ih some echnical eails, he posiioning algoihm an block iagam base on fuzz logic conol, epeimenal esuls an finall some conclusions an fuhe eelopmen possibiliies. II. FESTO OBOTINO PLATFOM Feso oboino is a holonomic mobile obo ih hee omni iecional ie unis, meaning ha he conollable egees of feeom equal he oal egees of feeom of he obo. Po-

2 ee b DC moos equippe ih opical shaf encoes he oboino can each spees of up o 0km/h. Fuhemoe, inechangeable pinions allo fo cusom geaing fom :4 o :6 [7]. A. Technical specificaions Some of he oboino echnical specificaions ae lise in Table [7]. TABLE I TECHNICAL SPECIFICATION OF THE FESTO OBOTINO HADWAE PLATFOM No. oboino obo imensions: - 70mm iamee, 0 heigh, kg oeall eigh an 5kg maimum paloa. Sensos: - nine Shap GDD0 infae isance sensos, analogue inucie senso, bumpe ih inegae senso, o opical sensos, ebcam ih USB ineface, hee opical shaf encoes Embee Conolle: - PC04 MOPSlcVE pocesso of 00MHz, SDAM 64MB, 8MB Compac flash ca ih C libaies fo accessing he oboino, Wieless LAN ineface boa. Inefaces: Ehene, USB, S-, Keboa an mouse, paallel po. 4 I/O ineface ca: - oupus fo conolling he hee omni iecional ie unis, 0 analogous inpus 0 0V, 50 Hz, o analogous oupus, 6 igial inpus/oupus, hee elas The opeaing ssem of he oboino is iie ino o laes, being a egula Linu lae an a eal Time Linu TLinu lae. All haae access goes hough he TLinu lae, hile he Linu lae poies sana use space. Also, he eal ime conol of he obo can be mae emoel fom anohe PC using he TLinu lae an ieless communicaion. Bunle ih oboino plafom, Feso poies an Applicaion Pogamming Ineface API calle oboinocom. The API offes he funcions fo ieless communicaion an fo accessing sensos an acuaos [7]. In ou case, oboino conol poceue fom Malab language ia ieless communicaion is simplifie b using he oboino Malab Toolbo. The infomaion abou he oboino posiion is obaine using he opical shaf encoes an ea eckoning meho obo oome, hile he obsacles aoiance equie he infae isance sensos. These infae sensos allo he obsacles eecion locae a isances less han 0cm. B. obo oome obo oome means he use of aa fom he moemen of he hee acuaos o esimae he obo posiion oe ime. In he cuen esign poblem e ill use he oome o esimae he mobile obo posiion elaie o he knon saing locaion. So, using he kinemaical moel of he obo an b inegaing he obo eloci e fin he mobile obo posiion. Opical encoes ill poie he basic aa o esimaing he obo s posiion an oienaion oas saing locaion. This is a cheap an quick soluion ih goo accuac o sho-em if e consie he assumpions: - he ficion beeen he heels an he floo is infinie; - he cene of mass is locae a he geomeical cene of he obo; - he isance beeen he cene of he obo an he cene of he heel cuenl ouching he goun is consan. Fig. shos he kinemaical moel of he obo. Fig. shos he obo an he obo epice o highligh heinfae sensos an DC moos. Figue. Kinemaical moel of he mobile obo. Figue. Feso oboino ih infae sensos an DC moos. Theo of geome an oaion is use o eelop he moels fom Fig.. efeing o he geome use fo eiing he oboino kinemaical moel e efine o cooinae ssems. Fis cooinae ssem is fie o he enionmen, calle ol cooinae ssem. The secon ssem is fie o he mobile obo an i is name obo cooinae ssem. To be able o isinguish beeen elociies elaie o he o cooinae ssems menione aboe he folloing efiniions nee o be inouce: - obo eloci is he eloci elaie o he obo cooinae ssem; - ol eloci is he eloci elaie o he ol cooinae ssem. The elaionship beeen heels elociies an ol elociies can no be eie. We mae he calculus in o sages. Fis sage consiss in he ansfomaion fom he heels elociies o he obo elociies o inese. We efine he folloing aiables: - i is he angula eloci of he heel i he angula elociies of he heels escibe he eco h ; - i is he eloci of each iniiual heel he anslaional elociies of he heels escibe he eco h ;

3 - he aius of he heel; - he isance fom he heel o he cene of he obo; - an chaaceize he obo cooinae ssem; - Ω he angenial oaional eloci of he obo; - φ i escibes he oaion of he heel shaf compae o he obo cooinae ssem. Ω cos sin cos sin cos sin h Deemining obo elociies fom heels elociies can be one b ineing he mai. The secon sage eas he elaionship beeen he heels elociies an he eloci of he obo epesse in he ol cooinae. Ω cos sin cos sin cos sin h h h hee - an chaaceize he ol cooinae ssem; - is he oaion angle of he obo cooinae ssem compae o he ol cooinae ssem. In he ne secions e simplifie he fomulas b eplacing he ansfomaion mai fom he heels elociies o he ol angula eloci ih T h. Using he epessions eie aboe, i is possible o eemine he obo s ol eloci fom he measuemens of he angula elociies of he hee heels b ineing he mai T h. Ω T h Equaions, an ae some basic elaions o fin he obo posiion in he human enionmen. Dea eckoning meho gie us a simple mahemaical poceue o esimaing he cuen posiion of he obo base on peiousl eemine posiion hen he eloci an elapse ime unil he cuen posiion ae knon. The esimae posiion b moing he obo fom he ime momen 0 a he ime momen is eemine using 4. [ ] > 0 0,0,0 h T 4 hee - an ae he ol cooinae ssem a ime momen ; - he oienaion angle a momen ; -,0 an,0 ae he ol cooinae ssem a momen 0 ; - 0 he oienaion angle a momen 0. A isaanage of ea eckoning is ha since ne posiions ae calculae solel fom peious posiions, he eos of he pocess ae cumulaie, so he eos in he posiion esimaion go ih ime. III. THE POSITION CONTOL SYSTEM FO THE OBOTINO MOBILE OBOT The block iagam of he posiion conol ssem fo he oboino mobile obo is shon in Fig. 4. The conol scheme has o feeback loops. The main feeback loop is impoan fo he obo posiion conol an poies he infomaion abou he cuen posiion elaie o he esie posiion, hile he ohe loop uses he infae isance sensos o eec he obsacles in he human enionmen an o moif he opimal ajeco so ha he obsacle o be aoie. Figue 4. The block iagam of he posiion conol ssem. The ne aiables hich appea in he Fig. 4 ae he esie posiion an oienaion of he obo, an, he oienaion angle eo e, isance eo e, isance o he obsacle obs, angle of he obsacle eecion obs, olages fom he isance sensos V V 9, linea elociies an of he obo in he O an O iecions, posiion an oienaion of he obo,,. The obo moule conains he omni ie componen hich ansfoms he obo linea elociies in he heels elociies, he inenal PID conolle fo he heels elociies, he Dunke DC moos hich ie he obo, he mechanics an ohe aiional componens. The block iagam highlighs also he obo sensos, infae isance sensos an opical shaf encoes.

4 The kinemaical moel moule esimaes he cuen posiion of he obo using he ea eckoning meho using 4. This moule has as inpus he heels angula elociies eemine using he opical shaf encoes an as oupus alues hich chaaceize he cuen bi-imensional posiion an he obo oienaion. The obsacle eecion uni uses nine isance sensos o eec obsacles ihin a isance up o 0cm. Because he sensos ae place a an angle of 40 egees, hee ae so calle inisible poins. Thus, he eecion as ese ih lage objecs. Depening on he olages measue fom he isance sensos 0.4V-.54V alues epesen 4cm-0cm isances he eecion moule poies he isance obs an angle obs a hich he obsacle is if an obsacle eiss. Aoiance conol moule compues he oienaion angle eo e an isance eo e knoing he esie posiion of he obo an he cuen posiion using 5. e e 5 If an obsacle is eece b he eecion uni hen o he oienaion angle e eo is ae he obsacle angle obs. The fuzz logic conolle has he ole o lea he obo o he esie posiion. The esign of fuzz conolle can be esume o choosing an pocessing he inpus an oupus of he conolle an esigning is fou componen elemens he ule base, he infeence engine, he fuzzificaion an he efuzzificion ineface [8, 9]. We choose as inpus ino he conolle he oienaion angle eo e an isance eo e. Also e consie o oupus: he elociies of he obo in he ol cooinae ssem hich ae he linea elociies an in he O an O iecions. The uniese of iscouse of he aiables ha is, hei omain as consiee o coe he pacical alues. We use membeship funcions fo he oienaion angle eo an fo he oupus an 7 membeship funcions fo he isance eo. All hese funcions hae a iangula shape. The linguisic alues ha chaaceize he linguisic aiable ae: - fo he oienaion angle eo: Negaie Infinie NIN, Negaie Ve Lage NVL, Negaie Lage NL, Negaie Mile NM, Negaie Small NS, Negaie Ve Small NVS, Zeo ZE, Posiie Ve Small PVS, Posiie Small PS, Posiie Mile PM, Posiie Lage PL, Posiie Ve Lage PVL, Posiie Infinie PIN; - fo he isance eo: Zeo Z, Ve Close VCL, Close CL, Mile M, Fa F, Ve Fa VF, Infinie IN; - fo he linea elociies: Tubo Backa TBW, Ve Fas Backa VFSBW, Fas Backa FSBW, Backa BW, Slo Backa SLBW, Ve Slo Backa VSLBW, Sop S, Ve Slo Foa VSLFW, Slo Foa SLFW, Foa FW, Fas Foa FSFW, Ve Fas Foa VFSFW, Tubo Foa TFW. Figue 5. Membeship funcions fo he fuzz conolle. The fuzz conolle implemens a ule base mae of a se of IF-THEN pe ules. These ules ee eemine heuisicall base on he knolege of he plan. The esuling ule ables fo he an linguisic aiables ae shon in Fig. 6. Figue 6. ule ables fo he fuzz conolle.

5 Some eamples of IF-THEN ules fo he linea elociies in he O an O iecions ae he folloing: IF e is negaie small NS an e is close CL THEN is slo foa SLFW IF e is negaie small NS an e is close CL THEN is foa FW The ules quanifies he siuaion hee he mobile obo is close o he esie posiion ih a negaie small oienaion angle eo, hence a slo foa eloci in he O iecion an a lile moe foa eloci in he O iecion ae neee o compensae he oienaion angle eo an o aance oas he esie posiion. The min-ma infeence engine as chosen, hish fo he pemises, uses maimum fo he O opeao an minimum fo he AND opeao. The conclusion of each ule, inouce b THEN, is also one b minimum. The final conclusion fo he acie ules is obaine b he maimum of he consiee fuzz ses [8]. To obain he cisp oupus, he cene of gai efuzzificaion meho is use. These cisp alues ae he esuling conolle oupus. IV. EXPEIMENTAL ESULTS The posiion conol ssem as ese on he oboino mobile obo ih aious scenaios: obo moing foa ih/ihou obsacles, obo moing backa ih/ihou obsacles, posiion conol ih one o moe obsacles, posiion conol in he human enionmen ih saic o namic obsacles. Fo eample in he folloing paagaphs ae pesene he epeimenal esuls of posiioning he mobile obo in human enionmen ih o saic obsacles. Top ie of he oboino moing foa fom he sa poin o he goal an aoiing he obsacles ae shon in Fig. 7. Figue 7. Top ie of he oboino plane ajeco. The isance obs an he angle obs a hich he obsacle is ee calculae using he olage measue in ime fom nine infae isance sensos. The funcional signals fo he fuzz logic conolle meaning he oienaion angle eo e, he isance eo e an he linea elociies an epesening he oupus fom he conolle ae also pesene in Fig. 8. Figue 8. The funcional signals of he conolle.

6 The angula heels elociies, he Dunke DC moos cuens poie b he inenal PID conolles an he posiion of he obo in he ol cooinae ssem ae shon in Fig. 9. he oienaion angle eo an he isance eo, an as oupus he linea elociies of he obo in he ol cooinae ssem hich ae ansfome b he omni ie moule o he heels elociies. Moemen saus infomaion is obaine hough obo sensos. Opical shaf encoes an ea eckoning algoihm ae use fo cuen posiion esimaion, hile infae isance sensos ae useful fo he obsacle eecion. The epeimenal esuls confim ha he conolle can achiee ou objecie ih some limiaion. These opeaing limiaions ae gien b using he encoes o esimae he obo posiion. The saighfoa a o ack he obo s moemens b simpl inegaing eloci aa knon as oome ma become a souce of eo ssemaic o nonssemaic. Hoee, seeal eensions can be mae o he conol sucue, such as o incease he acking accuac an he pefomance leel. One impoemen o he ssem is o fin a meho in hich he oome aa is supplemene b ohe senso infomaion eg sona, lase scanning, imaging ha ae inepenen of he obo moemens. Anohe a o impoe he pefomance leel is o use he Kalman fileing in he sensoial aa, since his mehoolog is e suiable o cope ih saisical an sochasic senso aa. Acuall, one of he mos impoan applicaions of he eene Kalman fileing is a simulaneous localizaion an map builing. In he fuue e ill o combine he fuzz logic ih his pe of fileing o o a ohe sensos fo a bee posiion esimaion an conol. EFEENCES Figue 9. The angula heels elociies an ol cooinae ssem. V. CONCLUSIONS This pape suie he implemenaion of he posiion conol fo a mobile obo base on fuzz logic. The epeimens ee mae using he Feso oboino plafom. We eae also he obsacles aoiance in he human enionmen. The fuzz conolle alloe he use of heuisics hich moel he a a human oul conol he pocess ia he use of ule able. Since e geneall kno he a o conol he obo, he heuisics e chose in he esign of he fuzz conolle poe e useful. The fuzz conolle has as inpus [] C. Baen, Conol of mobile obo, 007. []. Siega, I.. Noubakhsh, Auonomous mobile obos, A Bafo Book, The MIT Pess, 004. [] A. Saffioi, Fuzz logic in auonomous obo naigaion, a case su, 997. [4] A. Saffioi, E. uspini, K. Konolige, Using fuzz logic fo mobile obo conol, In. Pacical Applicaion of Fuzz Technologies, pp , 999. [5]. Choomuang, N. Afzulpuka, Hbi Kalman file/fuzz logic base posiion conol of auonomous mobile obo, Inenaional Jounal of Aance oboic Ssems, ol., no., pp.97-08, 005. [6] L. Asuillo, O. Casillo, P. Melin, A. Alanis, J. Soia, L.T. Aguila, Inelligen conol of an auonomous mobile obo using pe- fuzz logic, Engineeing Lee, 006. [7] hp://.feso-iacic.com [8] K.M. Passino, S. Yukoich, Fuzz conol, Aison Wesle Longman, USA 998. [9] E. uspini, P. Bonissone, W. Pecz, Hanbook of fuzz compuaion, Ofo Uni. Pess an IOP Pess, 998. [0] S..G. Touino, A.J. Alaes, Fuzz logic conol ssem o he mobile obo moion hough eb, 00.