Automatic design of fuzzy controllers for car-like autonomous robots

Au oma ic Design o Fuzzy Con olle s o Ca -Like Au onomous Robo s Iluminada Ba u one, F ansisco J. Mo eno-Velo, San iago Sánches-Solano, and Aníbal Olle o IEEE TRANSACTIONS ON FUZZY SYSTEMS, VOL.12, NO.4, AUGUST 2004 So Compu ing, HI 2005 P ojec 1: P esen a ion o Jou nal Mia Wes e lund In oduc ion • One o he main ”p oblems” in obo ics is mo ion planning; an au onomous obo has decide which mo ions o ca y ou in o de o achie e a ce ain ask • This pape desc ibes he design and implemen a ion o a uzzy con ol sys em o an au onoumous ca -like obo o sol e he diagonal pa king p oblem • Compu e -aided design ools in X uzzy 3.0 (based on speci ica ion language XFL3) is used in he design, and he sys em is implemen ed and es ed on he obo ROMEO 4R Mo ing om A o B • I he e a e no obs icles, he p oblem is o ind he sho es pa h be ween wo poin s; a ini e sequence o wo elemen a y componen s: a cs o ci cle (wi h minimum u ning adius) and s aig h line segmen s. • Following his discon inuous sho es pa h be ween wo poin s means we ha e o s op he ca and eo ien he wheels a each discon inui y poin . • Con inuous-cu a u e pa hs has ea lie been ob ained by geome ical me hods (e.g. β-splines), ollowed by some pa h- acking echnique (e.g. p edic i e con ol me hods) • Ano he app oach is uzzy logic-based planne s based on heu is ic knowledge o expe d i e s by uzzy ules and/o lea ning hese ules wi h aining da a aken om he human d i ing beha iou Diagonal Pa king Maneu e • This sys em doesn’ conside he a oidance o un o eseen obs acles bu ocuses on pa king on a cons ained pa king place de ined by s a ic obs acles. • S a ing om a gi en posi ion (x,y) and o ien a ion φ , he ehicle shall a i e backwa ds a he desi ed pa king place wi h igh angle and s op he e. • Re e ences: Line o pa ked ca s below y=0, he cen e o he pa king place x=0, a ge o ien a ion φ =0 (-180°≤ φ ≤180°), he cu a u e o he ajec o y is posi i e i s ee ing wheel is u ned o igh , and nega i e o he wise Diagonal Pa king Maneu e (2) • The obo knows i s posi ion, o ien a ion and d i ing speed. • Kinema ic model: Ý x = ⋅sin( φ ) Ý y = ⋅cos( φ ) Ý φ = γ ⋅ ⎧ ⎨ ⎪ ⎩ ⎪ • Taking in o conside a ion dynamics ( ac ion and di ec ion engines eac wi h some dely) we ob ain he i s -o de model: ( )= e + ( −∆ )− e [] ⋅exp( − ∆ τ ) γ ( )= γ e + γ ( −∆ )− e [] ⋅exp(−∆ τγ ) ⎧ ⎨ ⎪ ⎪ ⎩ ⎪ ⎪ whe e el and γ el a e he speed and cu a u e alues om he con olle , and τ and τγa e he esponse imes o he ac ion and di ec ion engines whe e (x,y) a e he coo dina es o he ehicle ea axle midpoin , φis he obo o ien a ion wi h he e ical, is he speed, and is he ehicle cu a u e e =way⋅cel, γ e = w,i >0 bw,i ≤0 ⎧ ⎨ ⎩ • Values o he con olle (see nex slides) S uc u e o he Con ol Sys em • Dis inguish be ween wo con ol ac ions: deciding he d i ing di ec ion (backwa d o o wa d) and he magni ude o he speed, and selec ing he p ope angle o he wheels (depending on he d i ing di ec ion). • The e a e ou main modules connec ed in pa allel; way, cel, w, bw • Heu is ic knowledge exp essed linguis ically has been used when designing he di ec ion and speed modules ( ansla ed by XLF3). • Geome ic-based echniques has been used o op imizing he wo pa h planning modules o gene a e con inuous nea -minimal-leng h pa hs Di ec ion Fuzzy Con ol Module Two ule bases connec ed in se ies 1. mo ion: selec s o d i e o wa d, backwa d,o as p e iously done, depending on he posi ion and o ien a ion o he obo (i s goal is o a oid collision wi h he wo lines o ca s and wi h he ca s limi ing he a ge pa king place) 2. b ake: akes in o accoun he cu en speed o he obo o selec he d i ing di ec ion (wi hou o cing ab up changes in he obo speed) • De uzzo ica ion me hod in bo h ule bases is o maximum ype, i selec s as ou pu he consequen o he ule whose ac i a ion deg ee is maximum (i no ule is ac i e, de aul d i ing is backwa ds) Di ec ion Fuzzy Con ol Module (2) •mo ion: 1) I he y obo coo dina e is nea he ca s o he pa king place and he obo o ien a ion φis g ea e han -90°and smalle han 90°and he xcoo dina e is no ze o o he o ien a ion is no ze o, he d i ing di ec ion should be o wa d 2) I he y obo coo dina e is nea he ca s o he sidewalk in on o he pa king place and he obo o ien a ion φis g ea e han 90°o smalle han -90°, he d i ing di ec ion should be o wa d whe e nea pa king, nea wall, ze o a e ep esen ed by iangula membe ship unc ions; m 90, m 90n, o wa d a e c isp alues ep esen ed by 90, -90, 1 ansla ion o he ules in o he language XFL3 o X uzzy 3.0 • The d i ing di ec ion in he middle is he same as in he p e ious i e a ion, i he xcoo dina e o he o ien a ion is non-ze o, o he wise he di ec ion should be backwa d (in he middle a ea he ehicle can go backwa d o app oach he pa king place o o wa d o mo e away om he obs acles; in he las case, he o wa d di ec ion should be main ained un il cen e ing he ehicle app oxima ely (x=phi=ze o)). Di ec ion Fuzzy Con ol Module (3) • By assigning weigh s o he ules on can simpli y he ules.. • Rules o he second base b ake can be ob ained simila ly.. Tes ing.. • ”The expe imen al esul s ob ained con i m ha he designed con ol sys em mee s i s speci ica ions: he obo is s opped a he pa king a ge wi h he adequa e o ien a ion, collisions a e a oided wi h he pa king lo cons ain s, and sho as well as con inuous-cu a u e pa hs a e gene a ed du ing he o wa d and backwa d maneu e s.”