36 Scientific Journals 23(95)
Scientific Journals
Zeszyty Naukowe
Maritime University of Szczecin
Akademia Morska w Szczecinie
2010, 23(95) pp. 36–39 2010, 23(95) s. 36–39
Intersection model with configurable control system
Model skrzyżowania z systemem konfiguracji kontroli
Kazimierz Dzierżek
1, Michał Ostaszewski
2Bialystok University of Technology, Faculty of Mechanical Engineering Department of Automatics and Robotics
Politechnika Białostocka, Wydział Mechaniczny, Katedra Automatyki i Robotyki, 15-351 Białystok, ul. Wiejska 45a, e-mail: 1kazde@pb.edu.pl, 2mimek3@wp.pl Key words: control, traffic lights
Abstract
The following article presents algorithms of traffic lights control on intersection. A model allowing programming and testing of traffic lights according to established control algorithm was also presented. A visualization of program performance allowing preview of current states of program and remote exaction of entrance in order to check the correctness and stability of algorithm was created.
Słowa kluczowe: kontrola, sygnalizacja świetlna Abstrakt
Artykuł przedstawia algorytmy kontroli świateł ruchu drogowego na skrzyżowaniu. Model skrzyżowania po-zwala na programowanie i testowanie sygnalizacji świetlnej zgodnie z ustalonym algorytmem sterowania. Wizualizacja programu umożliwia podgląd aktualnych stanów programu i zdalne wymuszanie dostępu w celu sprawdzenia poprawności i stabilności.
Introduction
The process of human and goods translocation in the network of city streets is particularly complex not only due to its significant dispersion but, mainly, due to its non-linear, non-stationary and heterogenic character. The willingness of multiple subjects to use the same parts of network in the same time may lead to capacity overload, congestions, jams or gridlocks of parts of a city. The effects of aforementioned are decrease of safety, effectiveness and efficiency of travel as well as negative influence on environment and health of dwellers, particularly in city centers.
The continuous growth of number of vehicles caused by social-economic changes may lead to cities communication gridlocks. This may be de-scribed as overload of series of streets that may lead to blockade of some parts of a city. The most im-portant cause of such situation is limited possibility of city communication infrastructure development.
Traffic conditions in city depend not only on factors determined by street network features but also on factors related to traffic organization and supporting modern technical means implemented. The introduction of such means must be correlated with established city development strategy and communication policy preferences. Amongst the most important tasks is creation of instruments for practical implementation of established preferences. The basic mean supporting traffic organization and realization of assumed communication priorities are traffic lights allowing effective influence on streams of individual traffic as well as public urban transport. Elements characteristic for modern me-thods of influence on traffic are commonly found in presumptions to communication policy but support of necessary in such a case developed technical and organizational means is lacking. Traffic manage-ment systems with traffic control as one of its sub-systems are elements that may generate significant economic profits with relatively low expenditures.
Intersection model with configurable control system
Zeszyty Naukowe 23(95) 37
This is mainly a result of more optimal use of street network.
Model construction
In order to check the correctness of traffic lights control system performance a model of roundabout (Fig. 1). The model consists of 16 signal lights in 8 groups for vehicles traffic control and 8 signal lights in 4 groups for pedestrian traffic.
The model is also equipped with operating panel for control of its activity. This allows control of such features as:
turning on and off with START / STOP buttons; emergency mode (flashing yellow light) turned
on with EMERGENCY button;
call for pedestrian green light with PEDE-STRIAN1, PEDESTRIAN2 buttons;
rapid change of lights for emergency rides switched with RAPID1, RAPID2 buttons. A crepuscular sensor turning the model on inde-pendently was also used.
Fig. 1. Model of traffic lights Rys. 1. Model sygnalizacji świetlnej
The GeFanuc VersaMax Micro controller with mark UDR005 was used to control the model traffic lights. In order to lead full simulation of traffic on intersection, a circuit controlling vehicle traffic was installed. This circuit is controlled by GeFanuc VersaMax controller configured as slave.
Control systm configuration
The compact controller GeFanuc VersaMax Micro with mark UDR005 was used to work in network as Master. The master controller configu-ration consists in proper setting of network para-meters and loading the configuration into the con-troller. The configuration of port RS 485 used for communication between controllers connected into Multidrop or Point-to-Point network was presented
on figure 2. Using the port 232 however allows only Point-to-Point network.
Fig. 2. Master Controller Configuration Rys. 2. Konfiguracja sterownika głównego
In order to check connection correctness, con-trolling software allowing data exchange between Master and Slave controllers was designed. The program realizes data exchange reading register values (%R0100–%R0104) from Slave controller and saving them in memory register (from %R0400) of Master. Register data (%R0300– %R0305) are sent from Master and saved in Slave controller memory (from %R0200)
The controller GeFanuc VersaMax CPUE05 with extending digital I/O MDD 840 module was used as a Slave device. The configuration of com-munication port was presented on figure 3.
Fig. 3. Slave Controller Configuration
Rys. 3. Konfiguracja kontrolera podporządkowanego
Control of traffic lights on intersection
For proper operation of traffic lights two exem-plary algorithms were prepared:
a) constant-time control (Fig. 4), b) adaptive control (Fig. 5).
The algorithm shown on figure 4 executes procedures of particular signal lights service as follows:
Zs1 (Zs2) – procedure of signal lights switching on pedestrian crossing in direction 2 (switching to red) and on intersection in contractual direction 1; the procedure includes turning yellow signal light on, turning both yellow and red signals off subse-quently and turning green signal on.
Kazimierz Dzierżek, Michał Ostaszewski
38 Scientific Journals 23(95)
Z1 (Z2) – the procedure switching signal lights for entering the intersection in contractual direction 1; procedure includes turning yellow signal on, turning both red and yellow signals off subsequent-ly and turning green signal on as well as for pede-strian crossing in direction 1 (switching to green).
C1 (C2) – the procedure switching signal lights for entering the intersection in contractual direction 1; procedure includes turning green signal off, sub-sequent turning yellow signal on and turning red signal on afterwards.
The algorithm shown on figure 5 executes adap-tive procedures of signal lights service as follows:
Z1 > – marks increase in number of vehicles going through intersection in contractual direction 1 over 10% of assumed number,
T2 > – marks percentage of time T2 increase equal to percentage of Z1 change,
cZs1 – for presence sensor (inductive loop), T1 = c + 5 – „c‟ stands for number of vehicles expecting a pass.
Adaptive traffic algorithms are such, that during changing traffic conditions modify traffic control algorithms to optimize it. Adaptation amounts to the modification of signal plans for certain inter-section or certain group of interinter-sections. In the simplest algorithms, enrolment of vehicle or group of vehicles after reaching certain length of queue on yield junction of far lower traffic intensity causes green signal to turn on or lengthen for this junction.
Fig. 4. Constant-time Fig. 5. Adaptive traffic traffic control algorithm control algorithm Rys. 4. Stałoczasowy Rys. 5. Adaptacyjny algorytm kontroli ruchu algorytm kontroli ruchu
Fig. 6. General view of the “main window” of traffic light visualization Rys. 6. Ogólny widok okna głównego wizualizacji sygnalizacji świetlnej
“Open the control window” button “Open the main
Intersection model with configurable control system
Zeszyty Naukowe 23(95) 39
Intersection visualization
For visualization of traffic lights activity appli-cation in Intouch software by Wonderware was created. This application allows control and obser-vation of the model. For data exchange between controller and Intouch software GE Fanuc I/O ser-ver SNP was used. Data is exchanged through port 232 with controller marked as Master. General view of windows created in Intouch software is presented in figures 6 and 7.
Summary
The presented model of traffic lights on inter-section is very important for didactic process. The configuration of control system is also a significant task. The assumed method of switching lights requires design of process algorithm in the first place. On figures 4 and 5 two versions of algo-rithms out of multiple possible were presented. After analysis, student might elaborate control pro-gram. The software loaded into control system
manages the lights in accordance to assumed opera-tion algorithm. The presented model is addiopera-tionally equipped with vehicle traffic control system (con-troller plus control software). This matter is a sub-ject to other elaborations.
References
1. DZIERŻEK K.: GE Fanuc controllers programming [in Polish]. Wyd. Politechniki Białostockiej, Białystok 2007. 2. KWAŚNIEWSKI J.: PLC controllers in engineering practice
[in Polish]. Wyd. BTC, Warszawa 2008.
3. LIU H.L., OH J.-S.,RECKER W.: Adaptive signal control system with on-line performance measure. [in:] 81st Annual
Meeting of the Transportation Research Board, 2002. 4. GACA S.,SUCHORZEWSKI W.,TRACZ M.: Traffic
engineer-ing. Theory and practice [in Polish]. WKŁ, Warszawa 2009.
Recenzent: dr hab. inż. Kazimierz Peszyński, prof. UTP Uniwersytet Technologiczno-Przyrodniczy
w Bydgoszczy
Fig. 7. General view of “control window” for control of traffic light model Rys. 7. Widok ogólny okna kontroli do sterowania modelem sygnalizacji świetlnej
