Concept Pper Indoor utonomous Vehicle Nvigtion Fesibility Study Bsed on Infrred Technology Ry-Shine Run Zhi-Yu Xio * ID Deprtment Electronics Engineering, Ntionl United University, 36003 Mioli, Tiwn; rsrun@nuu.edu.tw * Correspondence: xio830525x@gmil.com Received: 6 September 2017; ccepted: 8 Jnury 2018; Published: 10 Jnury 2018 bstrct: ppliction utonomous s hs grown drmticlly in recent yers. Not only hs ril-guided (RGV) been used widely in trditionl production lines, utomtic guided (GV) hs lso been incresingly used. Positioning pth plnning re two mjor functions utonomous s; however, re re mny wys to fulfill bove requirements. infrred remote control hs been hevily successfully used in home pplinces for decdes, which hs encourged us to pply this mture cost-effective technology to n utonomous. By decoding coded signl from infrred light-emitting diode (LED), which is equipped on ceiling, utonomous cn be positioned with n ccurcy less thn 50 mm. On or h, by chnging bem pttern infrred light from ceiling, n invisible route cn be produced on ground. Tht is to sy, insted trditionl ril-guided method, se invisible pths cn guide utonomous. We hve implemented prototype n utonomous system bsed on bove concept, with im creting simple relible pproch for nvigtion n indoor utonomous. Keywords: utonomous ; positioning; pth plnning; infrred; invisible route 1. Introduction Positioning is key technology tht enbles development indoor utonomous s. re re vrious kinds useful pproches, such s rdio frequency identifiction (RFID) [1 3], ZigBee, WiFi [4 7], hve been proved in mny reserch studies over pst yers. Recently, robotics compny (Mrvelmind Robotics: Sunnyvle, C, US) hs even lunched n Indoor GPS with ±2 cm precision bsed on sttionry ultrsonic becons united by rdio interfce in license-free b [8]. Indeed, most problems positioning could be solved by ny bove methods. However, this pper verifies cost-effective method utilizing infrred technology. Not only cn positioning test be ccomplished by mking use mture encoding technology infrred signl, pth plnning hs lso been demonstrted by use invisible route (described ltter). Eventully, bsed on infrred technology, simple method for nvigtion n indoor utonomous hs been presented in this rticle. 2. Methods 2.1. Mechnicl Since crrying bility is not n issue for this study, smll toy-like tricycle ws dopted s test, which is shown on left in 1. re re two wheels, which re driven by dc motors, one in front, one idler in bck. chssis is mde up trnsprent crylic bord tht cn be used s pylod spce for electronic system (shown on right in 1). ppl. Syst. Innov. 2018, 1, 4; doi:10.3390/si1010004 www.mdpi.com/journl/si
ppl. Syst. Innov. 2018, 1, 4 2 10 ppl. Syst. Innov. 2018, 1, 4 2 9 ppl. Syst. Innov. 2018, 1, 4 2 9 () (b) () (b) 1. () Test ; (b) electronic system. 1. () 1. () Test Test ; (b) (b) electronic system. 2.2. Electronic 2.2. 2.2. Electronic Electronic Most efforts hve been focused on electronic issues. block digrm electronic Most Most efforts efforts hve hve been been focused focused on on electronic issues. issues. block digrm electronic system for test is shown in 2. detils re described below. system system for for test test is shown is shown in in 2. 2. detils detils re re described below. below. H Bridge H Bridge Driver 1 Driver 1 PWM-1 PWM-1 MCU MCU PWM-2 PWM-2 H-Bridge H-Bridge Driver-1 DC DC DC DC MOTOR-1 Ultrsonic Infrred MOTOR-2 Sensor x 5x 5 Module x 3x 3 Power Power Bnk Bnk (5 (5 Volt) Volt) 2. block digrm electronic system. MCU: microcontroller. PWM: pulse 2. 2. block block digrm digrm electronic electronic system. system. MCU: MCU: microcontroller. PWM: pulse width width modultion. modultion. modultion. 2.2.1. 2.2.1. 2.2.1. Motion Motion Motion Control Control Control two two two dc dc dc motors, motors, motors, DC DC DC MOTOR-1 MOTOR 1 MOTOR 1 DC DC DC MOTOR-2, MOTOR 2, MOTOR 2, re re re driven driven by by by H-Bridge H Bridge H Bridge Driver-1 Driver 1 Driver 1 H-Bridge H Bridge H Bridge Driver-2, Driver 2, Driver 2, respectively, respectively, PWM-1 PWM 1 PWM 1 PWM-2 PWM 2 PWM 2 signls, signls, which which re re provided provided by by microcontroller (MCU), (MCU), re re designed designed to complete to complete motion motion control control test. test. By djusting By djusting microcontroller (MCU), re designed to complete motion control test. By djusting duty rtio duty rtio PWM signls ppropritely, PWM signls ppropritely, four bsic types motion four bsic (forwrd/bckwrd/left types motion duty rtio PWM signls ppropritely, four bsic types motion turn/right (forwrd/bckwrd/left turn) cn be conducted turn/right well. turn) cn H-Bridge be conducted driverwell. hs been pplied H Bridge indriver mny hs reserch been (forwrd/bckwrd/left turn/right turn) cn be conducted well. H Bridge driver hs been studies pplied [9,10]; in mny thus, reserch its detils studies re omitted [9,10]; thus, here. its On detils re or omitted h, here. test On or hs h, lso been test pplied in mny reserch studies [9,10]; thus, its detils re omitted here. On or h, test equipped with hs lso fivebeen ultrsonic equipped sensors with (SRF05) five ultrsonic for obstcle sensors detection. (SRF05) for obstcle detection. hs lso been equipped with five ultrsonic sensors (SRF05) for obstcle detection. 2.2.2. 2.2.2. Infrred Infrred Module Module 2.2.2. Infrred Module Infrred Module consists n n infrred LED n infrred receiver whichis is shown in Infrred Module consists n infrred LED n infrred receiver which is shown in in 3. 3. infrred LED cn be driven by generl purpose I/O I/O pin pin MCU to MCU trnsmit to trnsmit invisible light (wvelength infrred LED round cn be 900 driven nm). by However, generl to rise purpose noise I/O immunity pin MCU environmentl to trnsmit invisible invisible light (wvelength round 900 nm). However, to rise noise immunity environmentl light, light (wvelength signl round is 900 nm). However, by 38 KHz to rise noise immunity environmentl light, light, infrred signl is modulted by 38-KHz crrier (pulse trin). Furrmore, pulse distnce encoding infrred ( signl so is clled modulted Nippon by Electric 38 KHz Compny crrier (NEC) (pulse infrred trin). Furrmore, (IR) trnsmission pulse protocol) distnce encoding ( so clled Nippon Electric Compny (NEC) infrred (IR) trnsmission protocol) is doptedis encoding dopted ( s so clled protocol Nippon communiction, Electric Compny n (NEC) illustrtion infrred pulse (IR) distnce trnsmission encoding protocol) is shown is s protocol communiction, n illustrtion pulse distnce encoding shown 4. dopted in s 4. protocol communiction, n illustrtion pulse distnce encoding is shown in 4.
ppl. Syst. Innov. 2018, 1, 4 3 10 ppl. Syst. Innov. 2018, 1, 1, 44 33 99 ppl. Syst. Innov. 2018, 1, 4 3 9 Infrred LED Infrred LED Infrred Receiver Infrred Receiver 3. infrred module: infrred LED infrred receiver. 3. 3. infrred module: infrred LED infrred receiver. 3. infrred module: infrred LED infrred receiver. 4. 4. 4. 4. timing timing illustrtion pulse pulse distnce encoding. 2.2.3. 2.2.3. 2.2.3. Positioning Positioning n for is in n n illustrtion illustrtion positioning positioning for for utonomous utonomous is is shown shown in in 5. 5. Two Two infrred LED lights re in in B) LED LED lights lights re equipped re equipped in different in different loctions loctions (sttions (sttions B) on ceiling, B) on which ceiling, will continuously which will s trnsmit continuously encoded trnsmit dt encoded s mentioned dt bove. s mentioned So, not bove. only will So, not utonomous only will utonomous know it it is is by wher it know is pproching wher it sttion is pproching by detecting sttion 38K-Hz by detecting pulse trin, 38K Hz utonomous pulse trin, utonomous cn cn lso lso tell tell which sttion it it is is by by decoding encoded infrred signl. s cn lso tell which sttion it is by decoding encoded infrred signl. s mtter course, mtter course, utonomous cn proceed to to vrious missions (ex. Pss through or utonomous cn proceed to vrious missions (ex. Pss through or Sty for 10 s ) by Sty for for 10 10 s ) s ) by by ppropritely encoding infrred signl from ceiling. ppropritely encoding infrred signl from ceiling. Sttion B Ceiling Sttion Sttion B rrived Pss Pss through Sttion rrived Sty Sty for for 10 10 10 s s 5. 5. illustrtion positioning for utonomous. 5. illustrtion positioning for utonomous.. 2.2.4. 2.2.4. Invisible Invisible Route Route 2.2.4. Invisible Route Insted Insted trditionl trditionl ril guided ril guided (or (or line trcing) line trcing) method, method, this this reserch reserch hs hs dopted dopted simple simple Insted cost effective cost effective trditionl pproch pproch ril-guided for for pth pth (or plnning: plnning: line-trcing) invisible invisible method, route route this cused cused reserch by by n n hs infrred infrred dopted bem. bem. simple Precisely Precisely speking, speking, cost-effective re re pproch will will be be n n for invisible invisible pth plnning: light light zone zone produced produced invisible route on on cused ground ground by when when n infrred infrred infrred bem. Precisely projection speking, comes from re willceiling, be n invisible light outer zone contour produced on invisible ground light when zone becomes infrred projection comes from ceiling, outer contour invisible light zone becomes projection invisible comes route. from Furrmore, ceiling, normlly outer round contour type contour invisible will light be zone when becomes infrred invisible LED is invisible route. Furrmore, normlly round type contour will be when infrred LED is route. is equipped Furrmore, stlone normlly on ceiling. round type However, contour re will will be be when semi circulr infrredcontour LED istype equipped if n equipped stlone on ceiling. However, re will be semi circulr contour type if if n stlone pproprite on piece ceiling. crdbord However, is put reclose willto be semi-circulr infrred LED. contour From type top if n view, pproprite n illustrtion piece pproprite piece crdbord is is put close to to infrred LED. From top view, n illustrtion two types invisible route is shown in 6. two types invisible route is is shown in in 6. 6.
ppl. Syst. Innov. 2018, 1, 4 4 10 crdbord is put close to infrred LED. From top view, n illustrtion two types invisible ppl. Syst. Innov. 2018, 1, 4 4 9 route is shown in 6. ppl. Syst. Innov. 2018, 1, 4 4 9 Stlone LED Stlone LED Crdbord Crdbord B B 6. 6. n n illustrtion different invisible routes. routes. 6. n illustrtion different invisible routes. dotted dotted line line rnge rnge in in 6 is 6 is so-clled so clled invisible invisible light zone. light Since zone. Since crdbord crdbord cn block cn dotted line rnge 6 is so clled invisible light zone. Since crdbord cn lmost block hlf lmost hlf infrred projection, infrred projection, it is not hrd it is to not imgine hrd to tht imgine semi-circulr tht semi circulr type contour type block lmost hlf infrred projection, it is not hrd to imgine tht semi circulr type will contour be produced will be byproduced this pproch. by this Obviously, pproch. Obviously, dimeter ( todimeter B) ( semi-circulr to B) portion semi circulr is contour will be produced by this pproch. Obviously, dimeter ( to B) semi circulr interesting portion is prt, interesting which needs prt, furr which explntion. needs furr explntion. portion is interesting prt, which needs furr explntion. n n illustrtion illustrtion invisible invisible line line trcing trcing nvigtion nvigtion is shown is shown in in 7. This 7. illustrtes This illustrtes test n illustrtion invisible line trcing nvigtion is shown in 7. This illustrtes test tht is equipped tht is equipped with two with infrred two infrred receivers receivers pssing through pssing through invisible light invisible zone, light it zone, is test tht is equipped with two infrred receivers pssing through invisible light zone, right on it is right trck on (see trck (see in 7). In in such condition, 7). In such one condition, infrred one receivers infrred will it is right on trck (see in 7). In such condition, one infrred receive receivers 38 will KHz receive crrier; however, 38 KHz crrier; orhowever, receiver gets nothing. or receiver No doubt, gets nothing. No only doubt, needs receivers will receive 38 KHz crrier; however, or receiver gets nothing. No doubt, to drive only twoneeds wheels to t drive sme two speed wheels to keep t on going sme speed right on to keep trck. on going Consider right nor on cse trck. only needs to drive two wheels t sme speed to keep on going right on trck. (see Consider b nor in cse 7), (see in which b in is going 7), deep in which into invisible light is going zone, deep both into Consider nor cse (see b in 7), in which is going deep into invisible two infrred light zone, sensors receive both 38two KHz infrred crrier. sensors Obviously, receive 38 KHz hscrrier. to djust Obviously, rtio invisible light zone, both two infrred sensors receive 38 KHz crrier. Obviously, speed hs two to wheels djust (mke rtio left speed turn) to be two bck wheels on trck. (mke left turn) to be bck on trck. hs to djust rtio speed two wheels (mke left turn) to be bck on trck. b b Infrred Receivers Infrred Receivers Wheel Wheel Wheel Wheel Idler Idler 7. n illustrtion invisible line trcing nvigtion. 7. n illustrtion invisible line trcing nvigtion. 7. n illustrtion invisible line trcing nvigtion. 2.2.5. 2.2.5. Pth Pth Plnning Plnning 2.2.5. Pth Plnning Bsiclly, Bsiclly, t lest t lest three three types types pth pth plnning plnning (left turn, (left go turn, stright, go stright, right turn) right re turn) needed re needed in order in for order nbsiclly, utonomous for n t utonomous lest three totypes complete to pth complete plnning mneuver. (left By mneuver. turn, cscding go stright, By multiple cscding right turn) bove multiple re semi-circulr needed bove in type order semi circulr invisible for n routes, type utonomous invisible simple routes, effective to simple complete method effective thtmneuver. fulfilled method By bsic tht cscding fulfilled requirement multiple bsic ws sserted requirement bove in this semi circulr ws reserch. sserted type in reltive invisible this reserch. position routes, djcent simple reltive infrred position effective LEDs, method djcent tht ngle infrred fulfilled inclintion LEDs, bsic requirement crdbord ngle close ws inclintion to sserted infrred this crdbord LED, reserch. re two close key to points reltive infrred position this method. LED, re djcent However, two key infrred points it is lso LEDs, esy this method. to underst However, ngle by inclintion it simple is lso esy geometricl to crdbord underst illustrtions close by to shown simple infrred geometricl LED, 8. re illustrtions two key points shown in this method. 8. However, it is lso esy to underst by simple geometricl illustrtions shown in 8.
ppl. Syst. Innov. 2018, 1, 4 5 10 ppl. Syst. Innov. 2018, 1, 4 5 9 ppl. Syst. Innov. 2018, 1, ppl. Syst. Innov. 2018, 1, 4 5 9 Left Turn Left Left Turn Turn Go Stright Go Go Stright Stright Right Turn Right Right Turn Turn 8. 8. n n illustrtion illustrtion pth pth plnning. plnning. 8. 8. n n illustrtion illustrtion pth pth plnning. plnning. 3. Results Discussion 3. 3. Results Results Discussion Discussion 3.1. 3.1. Experimentl Experimentl setups setups 3.1. 3.1. Experimentl Experimentl setups setups Using Using n n f shelf f--shelf internet internet protocol protocol (IP) (IP) cmer cmer with with night night vision, vision, pictures pictures (shown (shown in in n f shelf internet protocol (IP) cmer with night vision, pictures (shown Using 9) 9) n invisible f shelf invisible light light zone internet hve zone protocol been hve cptured been (IP) cmer cptured with with infrred with night vision, LEDs infrred tht pictures re LEDs equipped (shown tht 100 rein 9) invisible light zone been cptured with infrred LEDs tht re equipped 100 cm equipped (L) 9) 100 75 cm cm invisible (L (Lb) ) bove light 75 cm zone ground, (Lhve b ) bove been respectively. cptured ground, It with is respectively. esy to infrred identify It is LEDs esy two tht to types identify re equipped invisible two 100 types cm (L) invisible 75 cm route (Lb) from bove pictures, ground, since respectively. shrp stright It is esy line to identify prt semi-circulr two types type invisible route cm (L) from 75 pictures, cm (Lb) since bove shrp ground, stright respectively. line prt It is esy semi circulr to identify type two contour types (shown invisible contour route from (shown pictures, on right since in shrp 9) stright is obviously line prt seen. Onsemi circulr or h, type rdii contour (shown on route from right in pictures, 9) since is obviously shrp seen. stright On line or prt h, rdii type two contour invisible (shown light two invisible on right light in zones re 9) round is obviously 60 cm (Rseen. ) On 45 cm (R or h, rdii two invisible light zones re right round in 60 cm 9) (R) is obviously 45 cm (Rb), respectively, or b ), respectively, h, reltionship rdii reltionship between two invisible between rdius light zones rdius re round height 60 for cm (R) infrred 45 cm projection (Rb), respectively, cn be explined with reltionship geometry between demonstrtion rdius zones height re for round infrred 60 cm (R) projection 45 cm cn (Rb), be explined respectively, with geometry reltionship demonstrtion between shown rdius in shown height in for 10. infrred projection cn be explined with geometry demonstrtion shown in height 10. for infrred projection cn be explined with geometry demonstrtion shown in 10. 10. 9. Pictures invisible light zone. 9. 9. Pictures invisible light zone. 9. Pictures invisible light zone. θ θ Lb Lb Lb L L L Rb Rb Rb R R R 10. reltionship between rdius height for infrred projection. 10. 10. reltionship reltionship between between rdius rdius height height for for infrred infrred projection. projection. 10. reltionship between rdius height for infrred projection. view ngle θ test infrred LED cn be clculted by simple trigonometry below: view view ngle ngle θ test test infrred infrred LED LED cn cn be be clculted clculted by by simple simple trigonometry trigonometry below: below: tn(θ/2) = R/L = Rb/Lb (1) tn(θ/2) R/L Rb/Lb tn(θ/2) = (1) R/L = Rb/Lb (1) ccording to experiment dt mentioned bove, derived vlue θ is round 62 degrees ccording to experiment dt mentioned bove, derived vlue is round 62 degrees for both ccording cses, to this experiment is consistent dt with mentioned specifiction bove, (50~60 derived degrees) vlue θ IR is remote round control 62 degrees for for both both cses, cses, this this is is consistent consistent with with specifiction specifiction (50~60 (50~60 degrees) degrees) IR IR remote remote control control
ppl. Syst. Innov. 2018, 1, 4 6 10 view ngle θ test infrred LED cn be clculted by simple trigonometry below: tn(θ/2) = R /L = R b /L b (1) ccording to experiment dt mentioned bove, derived vlue θ is round 62 degrees for both cses, this is consistent with specifiction (50~60 degrees) IR remote control ppl. generl ppl. Syst. Syst. Innov. home Innov. 2018, pplinces. 2018, 1, 1, 4 4 6 lso, re re few videos cptured by bove IP cmer to demonstrte 6 9 9 nvigtion test. n exmple semi-circulr type pth plnning is shown in generl generl home following home pplinces. seril pplinces. lso, frme pictures lso, re re re few videos cptured by bove IP cmer to ( re 11). re few videos re more cptured vivid results by tht bove cn beip wtched cmer into demonstrte nvigtion test. n exmple semi circulr type pth plnning demonstrte supplementry nvigtion mterils. test. n exmple semi circulr type pth plnning is is shown shown in in following following seril seril frme frme pictures pictures ( ( 11). 11). 1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 11. 11. continuous continuous frme frme pictures pictures cptured cptured during during demonstrtion demonstrtion nvigtion. nvigtion. 11. continuous frme pictures cptured during demonstrtion nvigtion. 3.2. 3.2. ccurcy ccurcy Positioning Positioning 3.2. ccurcy Positioning 12 12 shows shows n n illustrtion illustrtion positioning positioning experiment. experiment. re re were were three three semi circulr semi circulr type invisible 12routes, shows nmed n illustrtion, B, C, respectively, positioningconctented experiment. into re stright were three line semi-circulr type invisible routes, nmed, B, C, respectively, conctented into stright line for for test. test. type infrred invisible signls routes, nmed sent to, B, invisible C, respectively, zones conctented B were not into encoded, stright however, line for test. infrred signls sent to invisible zones B were not encoded, however, infrred infrred signl signls sent sent to invisible to invisible zone C ws zones encoded Bs were n identifiction not encoded, however, sttion. On infrred infrred signl sent to invisible zone C ws encoded s n identifiction sttion. On or or signl h, to sent increse to invisible ccurcy zone C ws encoded positioning, s n identifiction third infrred receiver sttion. ws Onequipped or in h, h, to increse ccurcy positioning, third infrred receiver ws equipped in to rer increse test ccurcy (see positioning, 12). third infrred receiver ws equipped in rer test rer test (see 12). (see 12). Positioning Positioning Point Point C C B B third third 12. illustrtion positioning. 12. 12. illustrtion illustrtion positioning. positioning. In In beginning, beginning, test test moved moved t norml t norml speed speed (greter (greter thn 20 thn cm/s) 20 through cm/s) invisible through routes In invisible beginning, routes B. However, B. it test However, begn to it slow moved begn down t to slow when norml down speed front when infrred (greter front receivers thn 20 cm/s) infrred detected through receivers encoded invisible detected identifiction routes encoded signl. B. However, identifiction n, signl. test it begn n, to continued slow down test to move when continued t reltively front infrred receivers detected encoded identifiction signl. n, test continued to to move move t slower t reltively speed (less reltively slower thn slower speed 10 cm/s) speed (less until (less thn thn 10 10 cm/s) third receiver cm/s) until until detected third third receiver encoded receiver detected identifiction detected encoded signl, encoded identifiction n stopped identifiction signl, signl, n n stopped stopped immeditely immeditely t t positioning positioning point. point. 13 13 shows shows pictures pictures cptured cptured round round positioning positioning point. point. red red mrk mrk 10 10 on on ruler ruler ws ws set set s s preset preset position position point. point.
ppl. Syst. Innov. 2018, 1, 4 7 10 immeditely t positioning point. 13 shows pictures cptured round positioning point. red mrk 10 on ruler ws set s preset position point. ppl. Syst. Innov. 2018, 1, 4 7 9 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 13. pictures cptured round positioning point. 13. pictures cptured round positioning point. Tble 1 shows dt Tble positioning 1. dt experiment. positioning xperiment. dt in fset row(s) indicte distnce from preset point. ccording to dt in Tble 1, mximum positioning devition is No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 round Offset 30 mm. +4 +5 15 5 15 7 15 7 6 16 30 +2 25 14 29 9 5 13 0 +2 (mm) Tble 1. dt positioning experiment. Tble 1 shows dt positioning experiment. dt in fset row(s) indicte No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 distnce from preset point. ccording to dt in Tble 1, mximum positioning devition Offset (mm) +4 +5 15 5 15 7 15 7 6 16 30 +2 25 14 29 9 5 13 0 +2 is round 30 mm. 3.3. Trjectory nlysis Pth For semi circulr semi-circulr type invisible zone, light drk contrst dimeter mrgin is much stronger thn tht circulr rc mrgin. Tht is to sy, semi-circulr semi circulr type invisible zone is suitble for stright type guidnce. Idelly, trjectory utonomous shouldbe be stright line line when semi circulr semi-circulr type invisible routeis is pplied. Obviously, key problem is: How wide is line? 14 shows illustrtion trjectory nlysis pth. W is width cr body, which equls distnce between between two two front front wheels. wheels. S is S is spcing spcing between between two infrred two receivers infrred receivers in front. However, in front. However, D sts D forsts longitudinl for longitudinl dynmic rnge dynmic rnge trjectory. trjectory. detiled figure detiled is shown figure inis shown 15. in 15. D S W 14. n illustrtion trjectory nlysis pth.
stright line when semi circulr type invisible route is pplied. Obviously, key problem is: How wide is line? 14 shows illustrtion trjectory nlysis pth. W is width cr body, which equls distnce between two front wheels. S is spcing between two infrred receivers in front. However, D sts for longitudinl dynmic rnge trjectory. detiled figure is shown in 15. ppl. Syst. Innov. 2018, 1, 4 8 10 D S W 14. n illustrtion trjectory nlysis pth. ppl. Syst. Innov. 2018, 1, 4 8 9 14. n illustrtion trjectory nlysis pth. Highest Level Lowest Level D 15. illustrtion longitudinl dynmic rnge trjectory. 15. illustrtion longitudinl dynmic rnge trjectory. pprently, D is highly positively correlted with S. Precisely speking, it cn be expressed pprently, in eqution D is highly below: positively correlted with S. Precisely speking, it cn be expressed in eqution below: D W < S (2) D W < S (2) In this cse, 165 mm 30 mm. Tble shows dt experiment. In this cse, W = 165 mm S = 30 mm. Tble 2 shows dt experiment. Tble 2. dt longitudinl dynmic rnge trjectory. Tble 2. dt longitudinl dynmic rnge trjectory. No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Left No. 94 95 1 96 2 963 954 96 5 95 6 796 894 9 94 10 93 11 94 12 9413 9414 95 15 94 16 17 94 18 95 1994 2096 (mm) Right Left (mm) 94 95 96 96 95 96 95 96 94 94 93 94 94 94 95 94 94 95 94 96 265 267 268 267 266 266 266 265 264 265 263 263 263 264 265 265 265 266 264 265 (mm) Right (mm) 265 267 268 267 266 266 266 265 264 265 263 263 263 264 265 265 265 266 264 265 Tble 2 recorded 20 cruise trips test long invisible route t speed 10 cm/s. Tble 2 recorded 20 cruise trips test long invisible route t speed 10 cm/s. For ech trip, Left sts for lowest level tht left wheel reched. Similrly, Right sts For ech trip, Left sts for lowest level tht left wheel reched. Similrly, Right sts for highest level tht right wheel reched. ll dt were mesured in reltive for highest level tht right wheel reched. ll dt were mesured in reltive coordinte coordinte reference to fixed point (origin). finl effort ws to find out mximum reference to fixed point (origin). finl effort ws to find out mximum highest levels highest levels (which ws 268 mm in Tble 2), minimum lowest levels (which ws 93 mm in (which ws 268 mm in Tble 2), minimum lowest levels (which ws 93 mm in Tble 2). Tble 2). D i.e., so clled longitudinl dynmic rnge trjectory should be D i.e., so-clled longitudinl dynmic rnge trjectory should be difference between difference between two extreme vlues, which is: two extreme vlues, which is: D = 268 93 = 175 (mm) (3) D = 268 93 = 175 (mm) (3), D W = 175 165 = 10 (mm) < S (30 mm) (4), D W = 175 165 = 10 (mm) < S (30 mm) (4) In principle, result is consistent with bove discussion. However, obvious question is: is In principle, smller S result better? is consistent Indeed, with lrger S bove will discussion. led to However, reltively wider obvious stright question line is: is trjectory. smller But, S better? countereffect Indeed, might lrger rise S when will led to S reltively is smller wider thn stright threshold. line trjectory. 16 But, indictes countereffect trjectories might for rise different whensettings S is S. smller thn threshold. 16 indictes trjectories for different settings S. Highest Level Trjectory Lrger ʺSʺ Lowest Level verge Smller ʺSʺ verge Velocity 16. trjectories for different settings S.
, D W = 175 165 = 10 (mm) < S (30 mm) (4) In principle, result is consistent with bove discussion. However, obvious question is: is smller S better? Indeed, lrger S will led to reltively wider stright line trjectory. But, countereffect might rise when S is smller thn threshold. 16 indictes trjectories for different settings S. ppl. Syst. Innov. 2018, 1, 4 9 10 Highest Level Trjectory Lrger ʺSʺ Lowest Level verge Smller ʺSʺ verge Velocity 16. trjectories for different settings S. Not only would D D stop stop decresing, verge velocity test test could lso be be significntly reduced when S is smller thn threshold. In this reserch, by tril error, ~ ~2 4 cm is suitble S for for nvigtion on on invisible route. route. In In fct, fct, cruising speed is is nor point concern for for setting S. S. However, we we hve not not devoted too too much effort effort to to this this issue. issue. 4. Conclusions prototype n utonomous system bsed on mture infrred technology hs been implemented. lso, simple relible method positioning pth plnning for indoor nvigtion hs been proved on test. However, re is still much work left to improve nvigtion performnce in prcticl ppliction. For instnce, re must be more useful invisible contours infrred projection, which cn be produced by ingeniously processing crdbord. Furrmore, network tht could effectively mnge lots invisible routes, which my be intrictely linked toger, is nor key problem to be solved. We will continue to invest efforts in bove topics in ner future. Supplementry Mterils: videos this pper re vilble online t www.mdpi.com/2571-5577/1/1/4. Conflicts Interest: uthors declre no conflict interest. References 1. Liu, R.; Koch,.; Zell,. Pth following with pssive UHF RFID received signl strength in unknown environments. In Proceedings Intelligent Robots Systems (IROS), Vilmour, Portugl, 7 12 October 2012. 2. Liu, R.; Yuen, C.; Do, T.N.; Tn, U.X. Fusing Similrity-bsed Sequence Ded Reckoning for Indoor Positioning without Trining. IEEE Sens. J. 2017, 17, 4197 4207. [CrossRef] 3. Liu, R.; Yuen, C.; Do, T.N.; Jio, D.; Liu, X.; Tn, U.X. Coopertive Reltive Positioning Mobile Users by Fusing IMU Intertil UWB Rnging Informtion. In Proceedings IEEE Interntionl Conference on Robotics utomtion (ICR 2017), Singpore, 29 My 3 June 2017; pp. 5623 5629. 4. Ting, S.L.; Kwok, S.K.; Tsng,.H.C.; Ho, G.T.S. Study on Using Pssive RFID Tgs for Indoor Positioning. Int. J. Eng. Bus. Mng. 2011, 3, 9 15. [CrossRef] 5. Weekly, K.; Zou, H.; Xie, L.; Ji, Q.S.; Byen,.M. Indoor occupnt positioning system using ctive RFID deployment prticle filters. In Proceedings 2014 IEEE Interntionl Conference on Distributed Computing in Sensor Systems, Mrin Del Rey, C, US, 26 28 My 2014. 6. Zho, Y.; Dong, L.; Wng, J.; Hu, B.; Fu, Y. Implementing indoor positioning system vi ZigBee devices. In Proceedings 42nd silomr Conference on Signls, Systems Computers, Pcific Grove, C, US, 26 29 October 2008. 7. Yng, C.; Sho, H.R. WiFi-bsed indoor positioning. IEEE Commun. Mg. 2015, 53, 150 157. [CrossRef] 8. Mrvelmind Robotics. Precise (±2 cm) Indoor GPS: For utonomous Robots, Copters VR. 2017. vilble online: https://mrvelmind.com/.
ppl. Syst. Innov. 2018, 1, 4 10 10 9. Run, R.-S.; Yen, J.-C.; Tsi, C.-Y. Low Cost Implementtion GPS Guided Driverless Crs. In Proceedings 5th IEEE Conference on Industril Electronics pplictions (ICIE2010), Tichung, Tiwn, 15 17 June 2010. 10. Run, R.-S.; Chng, Y.-C.; Cheng, F.-C. Strightforwrd pproch utomtic Prking System- Trining-Recording-Ply Bck. In Proceedings 2012 IEEE Interntionl Symposium on Circuits & Systems (ISCS), Seoul, Kore, 20 23 My 2012. 2018 by uthors. Licensee MDPI, Bsel, Switzerl. This rticle is n open ccess rticle distributed under terms conditions Cretive Commons ttribution (CC BY) license (http://cretivecommons.org/licenses/by/4.0/).