Design and Implementation of Fuzzy Logic Controller for Intelligent Gantry Crane System

Transcription

1 10-12 May 2005, Kala Lmpr, Malaysia Dsign and Implmntation of Fzzy Logic Controllr for Intllignt Gantry Cran Systm Wahydi 1 and J Jalani 2 1 Dpartmnt of Mchatronics Enginring, Faclty of Enginring Intrnational Islamic Univrsity Malaysia, Jalan Gombak, Kala Lmpr, Malaysia 2 Dpartmnt of Mchatronics and Robotic Kolj Univrsiti Tknologi Tn Hssin Onn, Parit Raja, Bat Pahat, Johor, Malaysia 1 wahydi@iidmy, 2 jamalj@kitthodmy ABSTRACT Gantry cran is a machin that movs payload from on point to anothr point Rcntly, most of gantry crans s opn loop systm to control position whil anti-swing control is don manally by skilfl oprators Thrfor, skilfl oprators ar ndd to b traind in ordr to oprat th gantry cran fficintly and safly Th prformanc of th gantry crans ar havily dpnds on thir xprincs and capability This may not b practical to control th gantry cran bcas hman skills ar rstrictd by fatig problm and will affct th prformanc of th gantry cran In addition, it is wll known that opn loop systm is snsitiv to th paramtr variations and distrbancs To ovrcom th abov-mntiond problms, fdback control is adoptd in this papr Fzzy logic controllrs ar proposd for gantry cran systm Fzzy logic control is dsignd basd on information of th skilfl oprators Th ffctivnss of th proposd controllr is valatd xprimntally sing a lab-scal gantry cran Th xprimntal rslt shows that fzzy logic controllrs hav prodcd good rslt for anti-swing controllr 1 INTRODUCTION Gantry crans ar widly sd in indstry for transporting havy loads and hazardos matrials in shipyards, factoris, nclar installations, and high bilding constrction Th cran shold mov th load as fast as possibl withot casing any xcssiv movmnt at th final position Howvr, most of th common gantry cran rslts in a swing motion whn payload is sddnly stoppd aftr a fast motion [1] Th swing motion can b rdcd bt will b tim consming i rdc facility as wll as prodctivity Morovr, th gantry cran nds a skilfl oprator to control manally basd on his or hr xprincs to stop th swing immdiatly at th right position Frthrmor to nload, th oprator has to wait th load stop from swinging Th failr of controlling cran also might cas accidnt and may harm popl and srronding Th swing motion can b rdcd and stoppd withot sing th controllr Howvr, it will b tim consming and vntally rdc th facility and prodctivity of th gantry cran systm Evn thogh th skillfl oprators oprat th cran, thy will still fac som constraints sch as fatig problm This phnomnon can cas inconsistnt prformanc of th gantry cran systms and might cas accidnt Varios attmpts to control gantry crans systm basd on opn loop systm wr proposd For xampl, opn loop tim optimal stratgis wr applid to th cran by many rsarchrs [2-4] Thy cam ot with poor rslts bcas opn loop stratgy is snsitiv to th systm paramtrs (g rop lngth) and cold not compnsat for wind distrbancs Anothr important opn loop stratgy is th inpt shaping introdcd by Karnopp [5], To [6] and Singhos [7] Evn thogh thy claimd that inpt shaping is good in controlling th opn loop systm bt it still facs snsitivnss to th xtrnal distrbancs and paramtr variations In ordr to ovrcom th problms, this papr introdcs an intllignt gantry cran systm Th proposd intllignt gantry cran is ralizd by adopting fzzy-basd fdback controllrs Th proposd fzzy-basd controllrs consist of position as wll as anti-swing controllrs Fzzy logic control was dsignd basd on information of th skillfl oprators Th prformanc of th proposd intllignt gantry cran systm is valatd xprimntally on a lab-scal gantry cran Th 345

2 10-12 May 2005, Kala Lmpr, Malaysia xprimntal rslt showd that th intllignt gantry cran systm had prodcd good prformancs compard with th cran systm controlld by classical controllrs 2 PROPOSED CONTROL STRUCTURE Th strctr of th proposd controllr for th gantry cran systm is shown in Fig 1 Th proposd controllr consists of fzzy logic controllrs for both position and anti-swing control rspctivly Th objctiv of th proposd fzzy logic controllrs is to control th payload position X(s) so that it movs to th dsird position X rf (s) as fast as possibl withot xcssiv swing angl of th payload Θ(s) Th dsign of fzzy logic control is basd on xprt knowldg For xampl th xprt knowldg of skillfl oprator dring th maniplation of gantry cran systm is adoptd in fzzy logic controllr dsign It shows that fzzy logic controllr is a tchniq that can raliz th skill of hman oprators and th dsign rls dscrib th sbjctiv fzzinss of oprators xprincs instad of th s of control thory basd on mathmatical modl of th plant (s) X rf Θ(s) X(s) Fig 1 Proposd fzzy-basd atomatic gantry cran systm Fzzy logic controllr is on of th rcnt dvloping mthods in control that arnd its poplaritis Th ida bhind th fzzy logic controllr is to writ th rls that oprating th controllr in hristic mannr, mainly in If A Thn B format In gnral, as shown in Fig 2, fzzy logic controllr is constrctd by th following lmnts [8]: A rl bas (a st of If-Thn rls), which contains a fzzy logic qantification of th xprt s lingistic dscription of how to achiv good control An infrnc mchanism (also calld an infrnc ngin or fzzy infrnc modl), which mlats th xprt s dcision making in intrprting and applying knowldg abot how bst to control th plant A fzzification intrfac, which convrts controllr inpt into information that th infrnc mchanism can asily bing sd to activat and apply rls A dfzzification intrfac, which convrts th conclsions of th infrnc mchanism into actal inpts for th procss Anothr important part of fzzy logic controllr is lingistic variabl Lingistic variabl plays th ky rol in many of its applications, spcially in th ralm of fzzy xprt systms and fzzy logic control Basically, a lingistic variabl is a variabl rprsnting words or sntncs in natral langag For xampl, in th fzzy dsign controllr for gantry cran th words Ngativ Big (NB) for rror may corrspond to th Positiv Big (PB) or Positiv Small (PS) of th voltag whrby th actal Ngativ Big of rror rprsnts spcific rang val btwn -1 to1 in radians and tc In brif, th lingistic variabl is on of th important parts for tning procss of fzzy logic controllr to achiv th dsird control procss 346

3 10-12 May 2005, Kala Lmpr, Malaysia Fig 2 Fzzy controllr strctr 3 DESIGN OF FUY LOGIC CONTROLLERS Th main fatrs of th fzzy logic dsign procss consist of th dvlopmnt of inpt and otpt of th mmbrship fnctions In th cas of gantry cran, rror and rror rat of position and swing angl ar takn into considration as an inpt Manwhil, th voltag is takn as an otpt Sinc thr is no spcific form to b sd whn dsigning fzzy logic control [8], ths, th basic triangl and trapzoidal forms ar chosn for inpt and otpt mmbrship fnctions In most cass, th prformanc of fzzy control is minimally inflncd by th shaps of mmbrships, bt mainly by th charactristics of control rls [9] 31 Mmbrship Fnctions Th mmbrship fnctions for rror, rror rat and voltag of th position control consist of Ngativ (N), ro () and Positiv (P) as shown in Figs 3 and 4 rspctivly Th nivrs of discors is from -100 to 100 cm for rror, to 1285 cm/s for rror rat and -14 to14 for voltag Manwhil, mmbrship fnctions for rror, rror rat and voltag of anti-swing control consist of Ngativ Big (NB), Ngativ Small (NS), ro (), Positiv Small (PS) and Positiv Big (PB) as shown in Figr 46, 47 and 48 rspctivly Th nivrss of discorss of rror, rror rat and inpt voltag ar from -1 to 1 rad, -25 to 25 cm/s and -14 to14 V rspctivly Dgr of mmbrship µ Dgr of mmbrship µ Dgr of mmbrship µ Error cm (a) Inpt mmbrship fnction of rror Error rat cm/s (b) Inpt mmbrship fnction of rror rat N N N Voltag Volt (a) Otpt mmbrship fnction Fig 3 Mmbrship fnction of position control P P P Dgr of mmbrship µ θ Dgr of mmbrship µ θ Dgr of mmbrship µ - - Swing Angl rad (a) Swing angl mmbrship fnction Swing Angl Rat rad/s (b) Swing angl rat mmbrship fnction NB NB NB NS NS NS PS PS PB PB Voltag Volt (a) Otpt mmbrship fnction Fig 4 Mmbrship fnction of anti-swing control PS PB 347

4 10-12 May 2005, Kala Lmpr, Malaysia 32 Fzzy Rl Bas Th rls of fzzy position and fzzy anti-swing controls ar adoptd from oprator s knowldg and xprincs Basically, th oprator considrs th targt position, actal position and th cran spd dring opration Thrfor, rror and rror rat ar sd in ordr to gnrat th rls Tabls 1 and 2 list th gnratd lingistic rls for position and anti-swing control rspctivly Tabl 1 Fzzy rl bas of position control Error Rat/Error Error rat (t) P N P P P P Error (t) N P N N N N Tabl 2 Fzzy rl bas of anti-swing control Swing angl rat θ (t) Swing angl rat/ Swing angl PB PS NS NB PB PB PB PB PB PB Swing angl 33 Fzzy Infrnc and Dfzzification PS PB PS PS PS PS PB PS NS NB NS NS NS NS NS NB NB NB NB NB NB NB Th fzzy infrnc for position control has adoptd th Mamdani s Min-Max mthod which th fzzy control otpt µ v for th inpt µ is comptd as µ = [ µ µ ] (1) whr and dnot th maximm and minimm oprators rspctivly whil µ, µ v dnot dgr of mmbrships of th rror, rror rat and voltag control action rspctivly Manwhil, for th anti-swing control, th sam tchniq is sd for fzzy infrnc Th Mamdani s Min-Max mthod which th fzzy control otpt µ v for th inpt µ θ θ is comptd as µ = [ µ θ µ θ ] 2) whr µ, µ θ θ dnot dgr of mmbrships of th rror, rror rat and voltag control action rspctivly Frthrmor, in ordr to convrt th fzzy val to th crisp val of fzzy position and anti-swing control, th cntr of ara of dfzzification mthod is sd µ ()d o = (3) µ ()d whr is control inpt voltag obtaind sing Cntr of Ara (COA) dfzzification mthod o 4 IMPLEMENTATION AND RESULTS 41 Exprimntal Stp In ordr to valat th prformanc of th proposd controllrs, thy hav bn sd to control a lab-scal gantry cran systm Th xprimntal stp is shown in Fig 4 Th fzzy controllrs ar implmntd digitally on a prsonal comptr and is opratd with 1 ms sampling tim Th MathWork's MATLAB/Simlink is sd for ral-tim controllr implmntation throgh RTW and 348

5 10-12 May 2005, Kala Lmpr, Malaysia xpc Targt Th RTW nvironmnt provids a ral-tim opration sing prsonal comptrs and mltifnction I/O boards Howvr, th s of RTW still rqirs th dvlopmnt of cstom intrfac programs for corrct commnication with mltifnction I/O boards In ordr to ovrcom this problm, xpc Targt is incldd in th softwar configration Th xpc Targt softwar spports and provids bilt-in drivrs for many indstry standard DAQ card inclding th PCI-6024E DAQ card by National Instrmnt which is sd in th prototyp of th atomatic gantry cran systm A prsonal comptr is sd as a Host Comptr Windows oprating systm and othr rqird softwar ar rnning in th Host Comptr Th propsd controllrs ar dvlopd in Simlink sing its blocks and Fzzy Logic Toolbox, and thn it is bilt so that C cod is gnratd, compild and finally a ral-tim xctabl cod is gnratd and downloadd to th Targt Comptr Fig 5 Lab-scal intllignt gantry cran systm 42 Systm Prformancs Th prformancs of th proposd fzzy logic controllrs wr compard xprimntally with th and PD controllrs which ar dsignd and discssd in [10] Figrs 6 and 7 show th rsponss of gantry cran controlld by th proposd controllrs as wll as th classical controllrs whn th 40 cm and 70 cm stp inpt rfrncs wr sd Th dtaild prformanc comparisons ar shown in Tabl 3 for position control and Tabl 4 for anti-swing control Hr, th prformancs of position control systm wr valatd basd on ovrshoot, sttling tim, ris tim and stady stat rror On th othr hand, anti-swing control was basd on maximm swing amplitd and sttling tim Controllr /PD Fzzy/Fzzy Tabl 3 Positioning prformancs Rfrnc Ovrshoot Sttling tim Ris Tim Stady-Stat (cm) (%) (s) (s) Error (cm) Tabl 4 Anti- swing prformancs Controllr Rfrnc (cm) Maximm Amplitd (rad Sttling tim (s) /PD Fzzy/Fzzy

6 10-12 May 2005, Kala Lmpr, Malaysia Th rslts show that th fzzy logic controllr for position control gav smallr ovrshoot, shortr sttling tim, shortr ris tim and smallr stady-stat rror than th controllr Thrfor it can b concldd that, th proposd fzzy position control systm is bttr than th classical controllr Morovr, as shown in Fig 6(b) and 7(b), th fzzy logic controllr for anti-swing control gav fastr sttling tim than th PD controllr Althogh th maximm swing amplitd d to th fzzy logic controllr was slightly highr thn d to PD controllr, it was accptabl In gnral, th rslts confirmd that th fzzy logic controllrs wr sccssflly controlld th swing angl bttr than th PD controllr and prformd inconsistnt rslts at diffrnt dsird positions As th proposd fzzy logic controllrs giv a bttr prformanc than th classical controllr for both position and anti-swing controllrs, it can b concldd that th proposd fzzy-basd intllignt gantry cran systm is bttr than classical gantry cran systm Position cm Swing angl rad (a) Position rspons Swing angl rad Position cm (a) Position rspons (b) Swing angl rspons (b) Swing angl rspons Fig, 6 Rsponss to a 40 cm stp inpt Fig 7 Rsponss to a 70 cm stp inpt 5 CONCLUSIONS Th intllignt gantry cran systm has bn dvlopd by adopting fzzy logic controllrs Th proposd intllignt gantry cran systm contains two fzzy logic controllrs for controlling th both position and anti-swing motion of th payload Th both fzzy logic controllrs wr dsignd basd on th cran oprator xprincs Th prformanc of th proposd intllignt gantry cran systm was valatd xprimntally sing a lab-scal gantry cran Th rslt showd that th proposd systm had bttr prformancs compard with th classical cran systm REFERENCES [1] HM Omar, Control of Gantry and Towr Crans, MS Thsis, Virginia Tch, Blacksbrg, VA, 2003 [2] Y Sakawa and Y Shindo, Optimal Control of Containr Cran, in Proc Th 8 th Trinnial World Congrss of IFAC, Kyoto Japan, pp , Agst 1981 [3] GA Manson, Tim-Optimal Control of and Ovrhad Cran Modl, Optimal Control Applications & Mthods, Vol3, No 2, pp , 1992 [4] J Arnig, and H Trogr, Tim Optimal Control of Ovrhad Crans with Hoisting of th Load, Atomatic, Vol 23, No4, pp ,

7 10-12 May 2005, Kala Lmpr, Malaysia [5] BH Karnopp, FE Fishr and BO Yoon, A stratgy for moving mass from on point to anothr, Jornal of th Franklin Institt, No 329, pp , 1992 [6] CL To, CJ Ong and M X, Pls inpt sqncs for rsidal vibration rdction, Jornal of Sond and Vibration, Vol 211, No 2, , 1998 [7] WE Singhos, LJ Portr and W Sring, Inpt shapd of a planar gantry cran with hoisting, in Proc Amrican Control Confrnc, Albqrq, NM, pp , 1997 [8] KM Passino and S Yrkovich, Fzzy Control, Addison Wsly Longman, 1998 [9] HH L and SK Cho, A Nw Fzzy Logic Anti_Swing Control for Indstrial Dimnsional Ovrhad Crans, Thsis, Dpartmnt of Mchanical Enginring, Univrsity of Swon [10] Jamaldin J, Wahydi, Iswaini and Shaimi A, Dvlopmnt of Atomatic Gantry Cran Part2: Controllr Dsign and Implmntation, in Proc Th 5 th Indstrial Elctronics Sminar 2004, Srabaya, 11 Octobr