Research Article A Robust Longitudinal Control Strategy for Safer and Comfortable Automotive Driving

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1 Reseach Jounal of Appled Scences, Engneeng and Technology 7(3): , 014 DOI: /jaset ISSN: ; e-issn: Mawell Scentfc Publcaton Cop. Submtted: Febuay 18, 014 Accepted: Apl 09, 014 Publshed: June 0, 014 Reseach Atcle A Robust Longtudnal Contol Stategy fo Safe and Comfotable Automotve Dvng Abdelkade Meah and Kada Hatan Laboatoy of Electotechncal Engneeng, Unvesty Taha Moulay of Sada, Algea Abstact: A efeence model based contol appoach fo automotve longtudnal contol s poposed n ths study. The efeence model s nonlnea and povdes dynamc solutons consstent wth safety constants and comfot specfcatons. Moeove, a desgn pocedue of Adaptve Cuse Contol (ACC) and stop-and-go contol systems s povded whch deals wth the electc ca followng vaous scenaos n uban envonment. Snce many vehcle/oad nteacton factos (such as oad slope, aeodynamc foces) and actuato dynamcs ae vey pooly known, a obust fuzzy logc based contol stategy s futhe poposed n ths study. A set of smulaton esults showng the sutablty of the poposed technque fo vaous demandng scenaos s also ncluded n ths study. Keywods: Adaptve cuse contol, electc ca technology, longtudnal contol, stop-and-go contol, stop and go maneuves INTRODUCTION Taffc accdents have become socal touble along wth the ncease n dves and dvesfcaton. In taffc accdents the ea-end collson ncludes the sk of sevee njuy. Ths poblem can be sgnfcantly mpoved by optmzng the nte-vehcle dstance. Adaptve Cuse Contol (ACC) and stop-and-go contol systems have been thooughly studed n ecent yeas (Goodaz and Esmalzadeh, 007), Some of such eseach papes may be eamples of poblems elatng to longtudnal contol. Some othes may concen the nte-dstance contol n hghways whee the vehcle velocty emans manly constant. Whee as othes may deal wth the vehcle cculatng n towns wth fequent stops and acceleatons. In all stuatons, safety and comfot ae often the man goals but most often oppose each othe (Vahd and Eskandaan, 003). The pesent pape focuses on the ntegaton of the n-wheel electc motos nto the concepton and contol of oad vehcles. The novelty of the pesent wok s that the n-wheel electc moto s consdeed to be the only contol actuato sgnal n acceleaton and deceleaton phases, smplfyng the achtectue of the desgn of the vehcle and of the contol laws. A ecall the dynamc nte-dstance model fo geneatng a efeence dstance between the leade and followe ca was ntoduced n ths study (Matnez and de Wt, 007). The man contbuton of ths study conssts n fndng a fuzzy contol algothm that leads to the epected efeence speeds and acceleaton of the backwad vehcle, whle keepng a efeence dstance wth the vehcle n font. Moeove, the contol law wll have to be obust to a dstubance-oad nclnaton, aeodynamc foces o ollng esstance. METHODOLOGY Model and dynamc epesentaton of the vehcle: Snce the man goal of the analyss conssts n achevng only longtudnal contol of the vehcle, then the full model can easly be taken as a bcycle model, (Goodch and Boe, 000), as shown n Fg. 1. Hee, G s and G u ae espectvely the centes of gavty of the suspended and unsuspended mass, L f and L ae the dstances fom the cente of mass to the font and ea ale. The suspenson dynamcs ae taken nto account, wth the assocated load tansfe that ases when the vehcle s acceleatng o deceleatng. The foces that act on each ale ae shown n Fg. 1. The oveall system equatons ncludng the vehcle, wheel and load tansfe dynamcs ae gven as follows (Hatan et al., 010; Sekou et al., 013): M vv & F F es 1 F F + F + F es F F F F oll slope aeo aeo C µ M C M v V oll v ( S ) N g g sn α sgn slope ( ) p ( V ) Coespondng Autho: Abdelkade Meah, Laboatoy of Electotechncal Engneeng, Unvesty Taha Moulay of Sada, Algea Ths wok s lcensed unde a Ceatve Commons Attbuton 4.0 Intenatonal Lcense (URL: 506

2 Fg. 1: Bcycle analogy of the vehcle model Table 1: Electc vehcle paametes C L 1.41 (m) M v 166 (kg) h cg (m) g (m/sec ) L L f +L (m) C α p 0.00 (ad) R w 0.94 (m) µ p L f (m) S p 0.00 J v 630 (kg*m ) J w 1.84 (kg*m ) ( ) ( w Rw V w R V ) / w R w / V S N N f gm gm v L L L f L Moeove, R The wheel adus w aeo v w Res. J. App. Sc. Eng. Technol., 7(3): , 014 w R w R w w > V < V hcg V& α p gl hcg V& α p gl F The aeodynamc dag foce N / The nomal foce on the te f F The longtudnal te foce µ The longtudnal fcton w The wheel angula speed oll h cg L h F The ollng esstance foce ollng F The foce due to the slope of the oad L slope cg L (1) α p α p The dstance fom the cente of gavty to the ale and the nde f; wth the sgnfcaton: f font, ea, the values of the above paametes ae descbed n Table 1 The functon Kachoo wll be used to change the paamete µ S µ S S / µ + S whch s µ, ( ) ( ) p p p elated by a non-lnea functon to the wheel slp S, whethe motve o cubed and whee µ p and S p ae the peak values. Ths functon gves values compatble wth epemental data gven n Wdme and Le Sollec S (010), especally n the ange [ ] 507 Dynamc nte-dstance geneaton: The ntedstance efeence model descbes a vtual vehcle dynamcs whch s postoned at a dstance d (the efeence dstance) fom the leade vehcle. The efeence model s dynamcs ae gven by: d & && l & f () ( d d & ) & u, (3) f whee, & & l The font vehcle acceleaton & & f The followng vehcle s acceleaton, whch s a nonlnea functon of the nte-dstance and ts tme devatve Intoducng d ~ d 0 d n fomula (3), whee d 0 s the safe nomnal nte-dstance, the contol poblem would be then to fnd a sutable feed-fowad contol u, ~ when d > 0, such that all the solutons of the dynamcs () fulfll the followng comfot and safety constants: d dc, wth d c the mnmal nte-dstance & & γ, whee γ ma s the mamum attanable longtudnal acceleaton & J, wth J ma a bound on the dve ma ma desed jek In Wong (1978), the authos poposed to use a nonlnea dampe/spng model u -c, whch can be ntoduced n the dynamcs of fomula () to gve: && ~ d ~ ~ & c d d && l The pevous equaton may be analytcally ntegated and epessed backwads n tems of d as follow (Fg. ): d& c β & f ( d d ) + & ( t) 0 c ( 0) + ( d d ( 0) ) 0 l β Note that ths efeence nte-dstance depends upon the leadng vehcle, dstance d 0 and paamete c, whch s, n tun, an algebac functon of safe and comfot paametes d c, V ma, γ ma and J ma : (4)

Res. J. App. Sc. Eng. Technol., 7(3): 506-5033, 014 Fg. : The nte-dstance efeence model d 0 f &&& ( t) 16 V 7 β ma ma + d 7 V ma 8 β ma ma c V,.6 β 7β c 3 8V ma ma ma γ ma Fg.

FUZZY CONTROLLER Ths secton poposes a fuzzy logc algothm to contol the host vehcle. The dstance and the elatve velocty between the host vehcles ae the nputs of the fuzzy contolle.

3 Res. J. App. Sc. Eng. Technol., 7(3): , 014 Fg. : The nte-dstance efeence model d 0 f &&& ( t) 16 V 7 β ma ma + d 7 V ma 8 β ma ma c V,.6 β 7β c 3 8V ma ma ma γ ma Fg. 3: Poposed smulaton model Fnally, the feed-fowad contol law-o the followe acceleaton-yelds fom (3): && f u c d d d& 0 (5) whee, the nte-dstance evoluton comes fom the numecal ntegaton of (5). FUZZY CONTROLLER Ths secton poposes a fuzzy logc algothm to contol the host vehcle. The dstance and the elatve velocty between the host vehcles ae the nputs of the fuzzy contolle. Fuzzy contolle s sutable fo multpaametes and nonlnea contol poblems and the system tansfe functon s not equed. In ths study, Mamdan s Fuzzy Infeence method (FIS) s appled. The sngleton membeshp functon of the outputs s used. Ths type of output membeshp functon makes t convenent fo the defuzzfcaton pocess because t smplfes the computatonal effots compaed wth othe types of membeshp functon. The ente fuzzy system s developed and mplemented by usng MATLAB. Fgue 3, show the block dagam of the fuzzy contolle. The two nput vaables ae the elatve velocty and the dstance eo The block n the mddle epesents all the fuzzy nfeence ules whch ae the contol stategy of the poposed system. The output vaables ae used fo the contol of the bake and velocty. Each lngustc vaable contans seven tems. The meanngs of each nput vaable ae as follows: NL : Negatve Lage NM : Negatve Medum NS : Negatve Small PS : Postve small PM : Postve medum PL : Postve lage Z : Zeo (a) (b) (c) Fg. 4: Membeshp functons, (a) dstance eo, (b) elatve velocty, (c) output command The outputs ae dvded nto two sdes, the negatve one whch epesents the bakng command and the 508 postve sde whch epesents the velocty ato command (Fg. 4 and 5):

Output NL NM NS Z PS PM PL Relatve velocty NL NVL NVL NL NM NM NS NS NM NVL NL NM NM NS NS Z NS NL NM NS NS NS Z Z Z NM NS Z NS Z PS PS PS NM Z Z Z Z PM PL PM NS Z Z PS PM PL PVL PL NVL NVL NL NM NM

4 Res. J. App. Sc. Eng. Technol., 7(3): , 014 Table : The fuzzy ule of output command Dstance eo Output NL NM NS Z PS PM PL Relatve velocty NL NVL NVL NL NM NM NS NS NM NVL NL NM NM NS NS Z NS NL NM NS NS NS Z Z Z NM NS Z NS Z PS PS PS NM Z Z Z Z PM PL PM NS Z Z PS PM PL PVL PL NVL NVL NL NM NM NS NS Fg. 5: Suface NVL : Negatve vey lage NL : Negatve lage NM : Negatve medum NS : Negatve small PS : Postve small PM : Postve medum PL : Postve lage PVL : Postve vey lage Z : Zeo The fuzzy contol ules play an mpotant ole n fuzzy contol and also povde a shot descpton of the behavo of human conduct, so t s sgnfcant to establsh the fuzzy ules n the fuzzy contol system (Table ). Fg. 6: Motos otaton fo leadng and followe cas Fg. 7: Veloctes fo leadng and followe cas RESULTS AND DISCUSSION The leadng and followe cas wll be ntally unnng at dffeent speed, 0 9 / and 0 5 /. Besdes, the nte-dstance dynamc model s paametezed to povde a mamum speed V ma 30 m/sec, a mamum acceleaton B ma 7 m/sec and a mnmum nte-dstance d c 5 m. The slope angle α p 0. 01ad at (t 50 sec). A ca-followng wth a change n the pecedng vehcle velocty (Fg. 6 to 14): When the followe vehcle comes nea to the leadng vehcle, the velocty s adapted wth comfotable deceleaton and the efeence vehcle s postoned at a safe dstance. 509 Fg. 8: Relatve velocty between leadng and followe cas A stop-and-go scenao (Fg. 15 to 3): At (0 and 40 sec) and (70 and 80 sec) the leadng vehcle s

5 Res. J. App. Sc. Eng. Technol., 7(3): , 014 Fg. 9: Safety dstance, elatve dstance Fg. 13: Moto toques Fg. 10: Dstance eo Fg. 14: Load toques Fg. 11: Acceleatons fo leadng and followe cas Fg. 15: Motos otaton fo leadng and followe cas Fg. 1: Jeks fo leadng and followe cas 5030 Fg. 16: Veloctes fo leadng and followe cas

Res. J. App. Sc. Eng. Technol., 7(3): 506-5033, 014 Fg. 17: Relatve velocty between leadng and followe cas Fg. 1: Jeks fo leadng and followe cas Fg.

6 Res. J. App. Sc. Eng. Technol., 7(3): , 014 Fg. 17: Relatve velocty between leadng and followe cas Fg. 1: Jeks fo leadng and followe cas Fg. 18: Safety dstance, elatve dstance Fg. : Moto toques Fg. 19: Dstance eo Fg. 3: Load toques Fg. 0: Acceleatons fo leadng and followe cas 5031 Fg. 4: Motos otaton fo leadng and followe cas

5: Veloctes fo leadng and followe cas Fg.

Fg. 6: Relatve velocty between leadng and

7 Res. J. App. Sc. Eng. Technol., 7(3): , 014 Fg. 5: Veloctes fo leadng and followe cas Fg. 9: Acceleatons fo leadng and followe cas Fg. 6: Relatve velocty between leadng and followe cas Fg. 30: Jeks fo leadng and followe cas Fg. 7: Safety dstance, elatve dstance Fg. 31: Moto toques Fg. 8: Dstance eo 503 Fg. 3: Load toques

8 Res. J. App. Sc. Eng. Technol., 7(3): , 014 acceleated and deceleated (stop-and-go) wth a usual acceleaton value but hgh jek; howeve, the followng vehcle s mantaned to a safe dstance and wth bounded jek. A ca-followng wth had stop scenao (Fg. 4 to 3): At t 30 sec the leadng vehcle stops wth a hgh bakng value whle the followe vehcle comes to a complete stop befoe the ctcal dstance d c 5 m wth lowe bakng. CONCLUSION In ths study, a efeence model based contol appoach fo longtudnal contol fo an electc vehcle has been pesented. The poposed stuctue combnes a efeence model n whch the fome wll be to vefy the safety and comfot constants, whle the latte wll be n chage of the model-tackng. In ths study, the dstance contolle uses fuzzy algothm n whch the nputs ae the dstance and elatve velocty wheeas the outputs fom the contolle ae sepaated nto two goups. The fst one s the command to acceleate the vehcle and the othe output s the command to deceleate the vehcle n case of bakng command. The smulaton esults ncluded n ths study show that the ACC system whch s developed fo the AIT ntellgent vehcle s able not only to contol the vehcle to un at a desed velocty when opeated n velocty contol mode but also mantan effcently the dstance between the host vehcle and the obstacle vehcle. ACKNOWLEDGMENT REFERENCES Goodaz, A. and E. Esmalzadeh, 007. Desgn of a VDC system fo all-wheel ndependent dve vehcles. IEEE-ASME T. Mech., 1(6): Goodch, M.A. and E.R. Boe, 000. Desgnng human-centeed automaton: tadeoffs n collson avodance system desgn. IEEE T. Intell. Tansp., 1(1): Hatan, K., Y. Mloud and A. Mloud, 010. Impoved dect toque contol of pemanent magnet synchonous electcal vehcle moto wth popotonal-ntegal esstance estmato. J. Elect. Eng. Technol., 5(3): Matnez, J. and C.C. de Wt, 007. A safe longtudnal contol fo adaptve cuse contol and stop-and-go scenaos. IEEE T. Cont. Syst. T., 15(1): Sekou, M., K. Hatan and A. Daou, 013. Sensoless fuzzy dect toque contol fo hgh pefomance electc vehcle wth fou n-wheel motos. J. Elect. Eng. Technol., 8(1): Vahd, A. and A. Eskandaan, 003. Reseach advances n ntellgent collson avodance and adaptve cuse contol. IEEE T. Intell. Tans., 4(3): Wdme, M. and G. Le Sollec, 010. Intenshp epot: Smulaton and tacton contol of a vehcle wth fou n-wheel electc motos. Wong, J.Y., Theoy of Gound Vehcles. Wley, New Yok. The autho wsh to thank the helpful comments and suggestons fom my teaches and colleagues n Electo techncal Engneeng Laboatoy. 5033

3. A Review of Some Existing AW (BT, CT) Algorithms

3. A Review of Some Existing AW (BT, CT) Algorithms 3. A Revew of Some Exstng AW (BT, CT) Algothms In ths secton, some typcal ant-wndp algothms wll be descbed. As the soltons fo bmpless and condtoned tansfe ae smla to those fo ant-wndp, the pesented algothms