III I N T E R N A T I O N A L C O N F E R E N C E
T R A N S P O R T S Y S T E M S T E L E M A T I C S TST'03
P O L IT E C H N IK I Ś L Ą S K IE J 2003 T R A N S P O R T z.51, n r kol. 1608
m a rs h a llin g y a rd , m o d u la tio n o f w a g o n s sp eed , le a d in g to th e target, p o in t rela rd e rs
Janusz D Y D U C H 1 Mariusz B U Ł A W A 2
AN A P P L I C A T I O N O F T H E S T R A T E G Y „ L E A D I N G T O T H E T A R G E T ” T O M O D U L A T I O N O F W A G O N S S P E E D IN M A R S H A L L I N G Y A R D
T h e p a p e r p re sen ts the sy ste m o f m o d u la tio n o f w a g o n s sp eed in th e p ro c e ss o f sh u nting.
T h e sy stem is an im p le m e n ta tio n o f th e ‘le a d in g to th e ta rg e t’ strateg y , th a t is b a se d o n tw o fu n d am en tal elem en ts: c o n tro lle d p o in t re ta rd e rs lo cated alo n g the m a rsh allin g tra c k a n d its c o n tro l th a t re d u c es kin etic e n erg y o f ru n n in g w a g o n s in the w ay th a t th e sh u n ted w ag o n a rriv e s w ith p ro p e r sp eed to w ag o n s s tan d in g on so rtin g sid in g . T h e trials o f the sy stem are c arried on in P o zn an F ran o w o m a rsh a llin g yard now .
R E A L I Z A C J A S T R A T E G I I " P R O W A D Z E N I E D O C E L U "
W S Y S T E M I E R E G U L A C J I P R Ę D K O Ś C I W A G O N Ó W K O L E J O W Y C H N A S T A C J A C H R O Z R Z Ą D O W Y C H
W n in ie jsz y m a rty k u le p re z e n to w a n y je s t sy stem reg u lacji p rę d k o ści o d p rz ę g ó w w tra k c ie ro z rz ą d za n ia . S y ste m ten stan o w i w d ro ż e n ie strateg ii „ P ro w a d z en ie do c elu ” , o p a rte j na d w óch p o d staw o w y c h e le m en ta c h : ste ro w a n y c h h a m u lc ac h to ro w y c h u sy tu o w an y c h w z d łu ż to ru d o c elo w e g o o ra z ich s te ro w a n iu z a p e w n ia ją c y m z m n ie jsz e n ie en erg ii k in ety czn ej ja d ą c y c h o d p rz ę g ó w tak , że ro z rz ą d z a n y o d p rz ę g d o c h o d zi z o d p o w ie d n ią p rę d k o ś c ią do w a g o n ó w sto ją cy c h na to rze d o c elo w y m . B ad a n ia te g o sy ste m u s ą re a liz o w an e o b e cn ie n a stacji ro zrząd o w ej P o z n a ń F ran o w o .
1. IN T R O D U C T IO N
In the p ro cess o f w ag o n s sh u n tin g it is n ecessary to m o d u late the sp eed o f ru n n in g wagons in o rd e r to assu re safe re ach in g a rig h t place on the m arsh allin g track. G enerally, the retarder devices are co n tro lled in the w ay th at the w agon(s) reach the re q u e ste d p lace on the about 500-700 m long track w ith th e pro p er speed, ty p ically b elo w 1,5 m /s. T ak in g into consideration the v ariety w ag o n s (num ber, ty p e and technical condition o f veh icles) w ith different ro llin g and aero d y n am ic resistan ce, an d because o f variab ility o f w eath er condition,
'institute o f T ra n s p o rt, W arsa w U n iv e rsity o f T ec h n o lo g y , K o sz y k o w a 7 5 ,0 0 - 6 6 2 W arsa w , jd y @ it.p w .e d u .p l 2TENS Ltd, J a n a z K o ln a 2 6 C , 8 1 -8 5 9 S o p o t, M .B u la w a@ te n s.c o m .p l
106 Janusz D Y D U C H , M ariu sz B U Ł A W A control is m a d e in stro n g ly n o n -d eterm in istic co n ditions. A d d itio n ally , a location o f retarder devices d irectly lim its p o ssib ilities to in flu en ce a w ag o n s m o v em en t. T y p ic a lly used so lutions, b ased on ‘fire to th e ta rg e t’ m e th o d are sensitive on o ccu rren ce o f distu rb an ce s and the su p p lem en tary re m e d ie s are n eed ed , fo r ex am p le p u shing-dow n devices.
P resented so lution is an im p lem en tatio n o f “leading to the targ et” strategy, b ased on reducing kinetic e n erg y o f w agon b y tu rn in g on an d o f f p o in t retard ers, lo cated a lo n g w h o le w a y o f ru n n in g w agon.
2. T H E K IN E T IC M O D E L A N D C O N T R O L T A S K
A . T H E K IN E T IC M O D E L
O n the m a rsh a llin g track , eq u ip p ed w ith po in t retard ers and axle sen so rs (F ig .l) a w agon m o v es, th a t b o th m ass and axle sp read are know n (Fig.2).
F ig .l. L o c a tio n o f p o in t re ta rd e rs an d axle sen so rs alo n g a m a rs h a llin g tra c k
movement direction
zlN zK/K g
3
g4
g5
F ig .2 . A x le s p re ad o f w a g o n (s)
T h e p a ss a g e o f a w heel o f w ag o n above th e axle sen so r gives th e actual sp eed Vj and p o sitio n o f w agon s,-. T h e id en tificatio n m odel p resen ted b elo w [5] can b e u sed in o rd e r to e stim ate o n -lin e th e k in etic p a ram eters o f ru n n in g w agons.
s ( t ) = v( t ) t i < t < t M ( 1 )
v (< ) = a ( t ) t j < t < t M ( 2 )
107
s ( t) = v ( t) < I < tM K t , ) = Si
v(<,) = vi
à (t) = â u ( t) + â g {t) + â z (t)
(3) (4) (5) (6)
(7)
(9) (8)
a Zi ~ a z ( i -1)
à 20 = ¿ 0
(10)
F'z(t) = m ha2(t)
( 1 1 ) (12) where:
sA(t) - estim atio n o f w a g o n ’s p o sition at th e m om ent t vA(t) - estim ation o f w a g o n ’s sp eed at the m o m en t t aA(t) - estim atio n o f w a g o n ’s acceleration at th e m o m en t t azA - estim ation o f acceleratio n cau sed b y disturbances azA0 -in itia l acceleratio n cau sed b y disturbances FzA - estim ation o f d istu rb an ce force
0V, 0S - w eig h t co efficien ts
T he control sh o u ld assure th at w agon reach req u ested p o in t w ith m inim al sp eed and m inim al risk o f sto p p in g befo re reach in g p ro p er place. In view o f v ariety o f w ag o n s (num ber, type and technical c o n d itio n o f vehicles), w ith different rolling and aero d y n am ic resistance, and b ecau se o f v a riab ility o f w eath er condition, control is m ade in stro n g ly d isturbed conditions.
For the track section, w hen issue o f control is u n d er consideration, w e can evaluate tw o boundary curves o f loss en erg y fo r turn on and o ff retard er devices - so tw o b oundary trajectories. T h e lo w er b o u n d a ry trajecto ry reflects the energ y lost durin g the free m o v em en t o f w agon. T he u p p er b o u n d ary trajecto ry reflects energ y and location o f re ta rd e r devices along m arsh allin g track.
B. T H E C O N T R O L T A S K
108 Janusz D Y D U C H , M ariu sz BUŁAW A
F ig .3 . T h e p e rm itte d k in etic e n e rg y a rea and th e le a d in g c u rv e
T his b o u n d a ry tra je c to rie s d eterm in e th e area o f allo w ed kinetic e n erg y o f w agon(s).
T h ere is the risk o f n o t re a c h in g the targ et p o in t or an unsafe co llisio n w ith stan d in g on the track w ag o n s i f th e w ag o n kin etic en erg y is out o f the area.
O ne o f the p o ssib le strateg ies o f control is „leading to the ta rg e t”, in w h ich a trajectory su fficien tly d ista n t fro m b o u n d a ry trajecto ries is choosen to leave en ough safety m arg in . In this app ro ach , re q u ire m e n t o f p recise evalu atio n o f all forces affected a w agon is n o t so strong. T h is m ak es th e m e th o d re sista n t to an y kin d o f distu rb an ces o f control process.
F or im p lem en tatio n o f control assu rin g th e p ro p e r d ecrease in w a g o n ’s k in etic energy, a “leading c u rv e ” , a p p ro p ria te to req u ested trajecto ry , co u ld be s e t . W ith o u t g o in g in to detail, i f the k in etic e n e rg y is o v e r th e lead in g curve the retard er dev ices sh ould be on p o sition ON, o th erw ise th ey are O FF.
3. IM P L E M E N T A T IO N
T he „ le a d in g to the ta rg e t” co n cep t is a b asis o f th e S A R P O system - a system o f speed m o d u latio n o f w agons in m arsh allin g yard d ev elo p e d an d tested n o w in P oland. T h e structure o f the S A R P O system is b u ilt aro u n d tw o b asic units:
• T rack sid e devices: p o in t retard es, axle sensors and w heel lo ad sensors
• D istrib u ted control sy stem b a se d on field controllers co n n ected b y C A N ty p e extended netw o rk an d th e m ain co n tro ller w o rk in g u n d er Q N X v .4 .0 - re a l-tim e operating system .
T he system p erfo rm s its principal function - speed m o d u latio n o f w ag o n s b y the im p lem en tatio n o f th ree su b sy stem s i.e:
1. L o calisatio n o f w ag o n s su b sy stem 2. E stim atio n o f w a g o n s ’ sp eed su b sy stem 3. R etard e r control su b sy stem
109
The d eterm in atio n o f w a g o n ’s actual po sitio n and estim ation o f speed alg o rith m s are based on the in fo rm atio n co m in g from axle sensors placed on the track e v ery 30 m. T he passage o f a w heel above the sen so r gives the actual speed and p o sitio n o f w agon. T hat information is given o n ly in d iscreet m o m en ts and a prediction algorithm to d eterm in e on-line speed and p o sitio n is im p lem en ted [5].
S peed m o d u latio n o f w agons relies on control o f retard ers in the w ay to assure safe reaching b y the w agon the rig h t place. T he concept o f “leading c u rv e” is im p lem en ted [3].
The system tracks the k in etic energy o f w agons and m inim ises the d ifferen ce betw een the leading curve and actual k in etic p aram eters o f object. T he ch o ice o f th e lead in g curve fo r the object takes in to co n sid eratio n p erm itted energetic area an d the kinetic p aram eters o f object running in front.
4. E X P E R IM E N T A T IO N
T he ex p erim en tatio n h as b een m ade in m arsh allin g yard at P o zn an F ran o w o station since S ep tem b er 2003. S om e re su lts are given below :
A bbreviations
Ek - kin etic e n erg y o f w ag o n , F w - leading curve,
Emax - upper b o u n d o f p erm itted area, Emin - lo w er b o u n d o f p erm itted area, Vo - initial sp eed o f w ag o n (s), Vd - speed o f w a g o n (s) at target, SH - location o f p o in t retard ers, Control - control retard ers signal
K inetic e n e rry & sp e ed 20034)3-13 09:37:16
2 x E a o s ( 2 x 4 axle, 142 t), target - 350 itv Vo - 5,08 rrVs, V d - 0,91 m b
Distance [m]
F ig .4 . S p e e d m o d u la tio n o f a lo ad ed w agon
1 1 0 Janusz D Y D U C H , M ariu sz B U Ł A W A
K inetic energy & speed 2003-03-12 10c29t07
2 x Eaos (2x4 axle. 4 2 1). target - 350 m, Vo - 5,28 m/s, Vd - 0,73 m/s
o SO 100 1 SO 200 233 300 3CO « 0
D istance |m |
F ig. 5. S p eed m o d u la tio n o f an e m p ty w ag o n
A n an aly sis o f estim atio n erro rs fo r the p ro p o sed co n cep t o f id en tificatio n o f kinetic p aram eters o f ru n n in g w ag o n s [5] an d th e ex p erim en tatio n resu lts are given in the p ap er [4].
5. C O N C L U S IO N
T he im p le m e n te d „ le a d in g to ta rg e t” co n cep t is a very in terestin g so lution to improve e fficien cy o f a b ig m a rsh a llin g yard as w ell as a sm all one. A n app licatio n o f field controllers and C A N type n e tw o rk red u ces th e w irin g a n d m ak es th e system m ore reliab le. A concept of use o f axle sen so rs to d eterm in e the k in etic param eters o f ru n n in g w agons seem s to satisfy the n eed s o f tracin g th e k in etic e n erg y an d lo catio n o f ru n n in g w agons. T he trials th a t are carried on P oznan F ran o w o m a rsh a llin g yard aim at co n firm in g the v iab ility o f th e system .
B IB L IO G R A P H Y
[1] D Y D U C H J.: N o w o c z e sn e te c h n ik i te le in fo rm a ty c z n e w tra n sp o rc ie szy n o w y m . K onferencja T R A N S C O M P , Z a k o p a n e 1999.
[2] D Y D U C H J.: T ra n s p o rta tio n sy ste m c e rtific a tio n w ith re s p e c t to EU a p p ro v a ls. T ra n s p o rt E n g in ee rin g XIV N r 2, V iln iu s 1999.
[3] B U Ł A W A M ., K R A J E W S K I R ., S T O L Z J.: S te ro w a n ie h a m u lc am i p u n k to w y m i. P o lite c h n ik a Radom ska, T R A N S P O R T N R 1 (1 5 )2 0 0 2 .
[4] B U Ł A W A M ., G O L IC K I R ., K R A J E W S K I R.: B łąd e sty m ac ji ru c h u o d p rz ę g u w s y ste m ie SA RP0.
P o litec h n ik a R ad o m sk a . T R A N S P O R T N R 1(17) 2003.
[5] B U Ł A W A M .: W y z n a c z a n ie p a ra m e tró w ru c h u o d p rz ę g u n a stacji ro z rz ą d o w ej. P o litec h n ik a Radomska.
T R A N S P O R T N R 1 ( 1 7 )2 0 0 3 .
R eview er: P rof. A ndrzej Lewiński
