ME Control Lab. Control of autonomous vehicles on a smart road. Research activities, related to

Transcription

1 ME Control Lab Rsarch activitis, rlatd to Control of autonomous vhicls on a smart road Dr. Shai Arogti Dpartmnt of Mchanical Enginring Bn-Gurion Univrsity of th Ngv

2 Intllignt ransportation Systms - Motivation Intllignt ransportation Systms (IS) includ a wid rang of tchnologis that ar aimd at improving transportation systms. Main goals includ improvmnt in, traffic fficincy, nrgy consumption, safty (by rmoving th human factor) and comfort (by rlasing drivrs from tdious tasks such as a long driv). Intllignt transportation systms motivats dvlopmnt of fficint control algorithms for a group of unmannd autonomous vhicls. Nw concpts of smart roads should b dvlopd, which allows autonomous vhicls and manually drivn vhicls on th sam road (intraction, coordination, tc.)

3 Smart road st bd W ar dvloping a concpt of a smart road to allow autonomous driving of almost standard vhicls on a highway. h traffic may includ also manually drivn vhicls. h systm is mainly basd on a distributd ntwork of snsors and controllrs, which ar a part of th road infrastructur.

4 Smart road - Exprimnts A road sction, usd as a Lab tst-bd. his sction is covrd with four camras. A saf nvironmnt for tsting IS algorithms

5 Smart road - Exprimnts Exprimntal Rsults rajctory (camra 1) Raspbrry Pi + Pi noir camra (for vision and control) rajctory (camra 2) Driving commands ar snt wirlssly

6 Smart road CarSim Simulation CarSim includs accurat, dtaild, and fficint mthods for simulating th prformanc of passngr vhicls. CarSim has a standard intrfac to MALAB/Simulink wnty yars of ral-world validation. CarSim Simulation Stag 1 Path following Cruising spd Stag 2 Path following Kping front Saf distanc (from vhicl ahad)

7 hr Gnrations Autonomous vhicls Dvlopmnt rnd Control of a singl vhicl Path following Collision avoidanc Control of a group of vhicl Coordinatd Path following Formation, collision avoidanc Intllignt (and saf) control of a group of vhicl E.g., Us control tools to dtct cybr attacks Intllignt dcision making

8 A tst bd to try path following algorithms (yar = 2004) DGPS Compass Path following controllr, basd on a ds1103 dspace controllr board Driving motor controllr (spd mod) Driving motor and gar Encodrs Mobil Computr (controllr intrfac) String motor String motor controllr (spd mod)

9 Exprimnt rsults: - way points dsird trajctory (dtrmind automatically by th vhicl controllr) nd point start point No. of Points = 17

10 Exprimnt rsults: trajctory EKF trajctory Way Points dsird trajctory

11 Smart road Architctur A multi-layr control systm architctur For xampl his is a cntralizd solution and hnc it is snsitiv to cybr attacks h local safty layr (not ntwork connctd) uss local prcption (basd on car snsors) to chck th validity of th rcivd commands. It ovrwrits driving commands if ths ar not consistnt with local information. Infrastructur vhicls Coordinator (traffic managr) assigns individual mods to individual vhicls Individual car controllr Spd and string commands Onboard control + Safty layr mod 1 mod 3 Individual car controllr Spd and string commands Onboard control + Safty layr Road stat Global prcption Standard car All cars position, hading and vlocity

12 Smart road Snsor and control rdundancy for fault dtction and accommodation Each autonomous vhicl is quippd with two local autonomous-driving controllrs, 1. For path (road) following ( string command). 2. o kp saf distanc from front vhicl ( spd command) hs local controllrs ar for mrgncy situations only (thy don t us trafic prspctiv). All Individual car controllrs (car-infrastructur loop) ar dsignd with a prscribd convrgnc rat (that srvs as a prformanc indx, rprsntd by a scalar numbr). his prformanc indx is chckd locally (with car onboard snsors,.g., by Mobily) If a valid prformanc indx is not masurd, local autonomous driving controllrs, ar activatd immdiatly Local snsing Commands from infrastructur

13 Coordinatd path following - Problm formulation Lt s b a smooth curv (paramtrizd by s ), and a point M dnots th closst point btwn th curv and th vhicl. h following modl dscribs th rlativ stat btwn th vhicl and th path. cos( r ) v s 1 ddistc( s) d dist vsin( r ) v tan( ) c( s)cos( r ) l 1 ddistc( s) whr cs r rprsnts th curvatur of is th rlativ angl, and d dist s is th distanc of th vhicl from th path.

14 Coordinatd path following - Problm formulation h goal is to solv two complmntary problms: An innr layr solvs th path following control problm of ach individual vhicl. his controllr nsurs that ach vhicl convrgs to th dsird path. An outr layr solvs th coordination control problm for th all group, by stting th vlocity of virtual vhicls (dnotd by s d ) which srv as rfrnc vhicls for th ral vhicls. In short, two control signals v and ar to b dsignd for ach vhicl such that, lim d 0 t dist lim 0 t lim ss 0 t d

15 Path following of individual vhicls h innr layr controllr is drivd by th chaind form approach h tracking rrors btwn th vhicl and th path (at M ) ar dfind as, distanc rror hading rror String angl rror ddist sin( ) 2 cs ( )cos ( ) tan( )cos( ) 1 d c( s) l dist And th string rat command is, v v dist c( s)cos ( ) c ( s)cos ( )sin( ) sin( ) tan ( ) [ 3 (1 d c( s)) (1 d c( s)) l dist 3 2 dist 3 dist (1 dist ( )) c( s)cos( )sin( ) tan( ) d c( s) c ( s)cos ( ) l cos ( ) 3 v v u] l(1 d c( s)) d c s cos( )

16 Path following of individual vhicls hs complx dfinitions (of tracking rrors and control) transforms th systm to th simpl chaind form modl v u v Now, ut () can b chosn as u Kv k k k v Dfin a wighd squar-rror function as On can choos K such that V Vv V p1, 0 1 p22 p33 p i his is th prformanc indx of th controllr. It is chckd locally with car onboard snsors.

17 Coordinatd path following control On th outr layr, th coordinatd problm is managd by dfining a virtual vhicl to ach controlld vhicl. A control law is ndd (for ach ral vhicl) to allow convrgnc to a virtual vhicl. h rror btwn a ral and virtual vhicl is s s s d aking th linar vlocity of th controlld vhicl as, 1 ddistc( s) v ( sd ( sd s )) cos( ) assurs, s s.

18 Simulation rsults h simulation illustrats a convrgnc of thr vhicls to a two lan road sgmnt, whil driving in diffrnt spds, bypassing ach othr and avoiding collisions fast mid slow In th prsntd cas: N 3 [ x t y t t t ] [ 2 3 / 4 0] [ x t y t t t ] [ 7 6 / 4 / 4] [ x t y t t t ] [ [ 0 0 d 0 0 ] [0 0] s t s t for all virtual vhicls 0] Dsird spds ar [ v v v 6 5 4] 1 2 3] [ d d d Vhicl lngth Safty zon l 1 [ d w] [ ] Path following control gains Coordination control gains [ k a a ] [ 2 2 4] [ ] [ ]

19 Simulation rsults h simulation illustrats a convrgnc of thr vhicls to a two lan road sgmnt, whil driving in diffrnt spds, bypassing ach othr and avoiding collisions fast mid slow Vhicl lngth Safty zon l 1 [ d w] [ ] Path following control gains Coordination control gains [ k a a ] [ 2 2 4] [ ] [ ]

20 Simulation rsults Som othr coordinatd motion xampls Convoy Rigid formation String

21 Othr rsarch activitis (but rlatd) Activ magntic barings: Dsign (for low losss) Control (nrgy fficincy) Applications: FESS, prcision motion Magntic lvitation Drivr assistanc systms: Activ stability (yaw control) Activ diffrntial Elctronic diffrntial Activ anti roll bar Halth Monitoring: Dtction and isolation of faults Modl basd approach Hybrid systms (continuous + discrt) Fault tolrant control Unmannd Aral Vhicl: Flight formation control Multi rotor UAVs Fault tolrant control Unusual dsigns (flying wing, )

22 Yaw Stability Control basd on Activ diffrntials Goal to prvnt vhicls from spinning and drifting-out, du to: High acclration manuvrs. Unxpctd yaw disturbancs. Activ diffrntials - allow lctronic control ovr Lft-Right torqu transfr: W dvlop control algorithm for wo typs of activ diffrntials Activ Limitd Slip Diffrntial (for a singl ngin vhicl) Elctronic diffrntial (for Elctric Vhicls with Indpndnt Motors

23 Yaw Stability Control basd on Activ diffrntials Elctronic diffrntial (for Elctric Vhicls with Indpndnt Motors

24 Halth monitoring Fault dtction and Isolation W ar dvloping modl-basd algorithms that dtct and isolat systm faults in ral tim. h algorithm dtcts inconsistncis btwn th masurd bhavior (by snsors) and th prdictd normal bhavior (by a modl). It also idntify th fault typ (i.., fault isolation) h mthod has bn implmntd on th CyCab (lctric vhicl) to dtct faults of its lctro-hydraulic string systm. h considrd faults wr: Snsor-faults: 1) Prssur snsors 2) incrmntal ncodr 3) absolut ncodr (string angl). Suddn faults: 1) A burnt DC-motor or drivr 2) A brokn-blt Paramtric faults: 1) A flat tir. 2) Piston intrnal lakag (du to wornsal, th piston fficincy is dcrasd)