Distributed Control Systems. Real-Time Systems.
Research team
Tiberiu Letia, Adina Astilean, Silviu Folea, Camelia Avram, Mihai Hulea, Radu Miron, Sergiu Barbu, Florin Danga, Sergiu Lungu, Dana Muresan, Florian Mihele, Ionut Pop.
Research fields
- Distributed Control Systems;
- Real-Time Systems
Recent research projects
“Control and Guidance System for Urban Vehicle Traffic”, national research grant funded by CNCSIS, A - 873, 2005.
“Intelligent Real-Time System for Railway Traffic Management, Information and Control”, national research grant funded by CNCSIS, 1537, (2007 – 2008).
“System for Fingerprint Identification with Broadcast Communication using Mobile Terminals”, national research grant funded by ANCS, CNMP PC-11-038/2007, (2007-2009).
Publications
T. Letia, A. Astilean, C. Avram, M. Chindris, A. Cziker, M. Hulea,”Distributed Hunting System of Voltage Sag Events”, 1st IFAC Workshop on Convergence of Information Technologies and Control Methods with Power Plants and Power Systems ICPS'07 , Cluj-Napoca, Romania, July 9-11, 2007, pp. 240-244.
A. Astilean, C. Avram, T. Letia , M. Hulea, ”Agent Based Route Planning for Rail Freight Transport”, The 8th International Control Carpathian Conference, ICCC Ostrava, Slovak Republic, May 24-27, 2007, pp. 150-156.
T. Letia, ”Avoidance of Urban Vehicle Traffic Congestions”, The 11th IFAC Symposium on Control in Transportation Systems, Delft, The Netherlands, Elsevier Publishing, 2006, pp. 183-189.
T. S. Letia. ”Real-Time Approaches of Urban Vehicle Traffic Control”, Proceedings of International IEEE-TTTC l Conference on Automation, Quality and
Testing, Robotics AQTR 2006 (THETA 15), Cluj-Napoca, May 25-28, 2006, pp. 346-350.
A. Astilean, S. Folea, “Design and Testing in Laboratory Environment of the Embedded Microsystem (ECAM)”, Proceedings of International IEEE-TTTC Conference on Automation, Quality and Testing, Robotics AQTR 2006 (THETA 15), Cluj-Napoca, May 25-28, 2006, pp. 442-447.
C. Avram, A. Astilean and T. Letia. “Multiagent Technology for an Urban Road Traffic Advisor“, Proceedings of International IEEE-TTTC Conference on Automation, Quality and Testing, Robotics AQTR 2006 (THETA 15), Cluj-Napoca May 25-28, 2006, pp. 340-345.
T. Letia, A. Astilean, C. Avram, M. Hulea, ”Distributed Coordination Method for Urban Vehicle Traffic Control”, International Carpatian Control Conference ICCC 2006, Ostrava, Czech Republic, May, 2006, pp. 345-348.
C. Avram, A. Astilean, T. Letia, ”Multiagent implementation of an urban Road Traffic Advisor”, Proceedings of European Conference on Modeling and Simulation. IEEE, Bon, Germany, 2006, pp. 730-736.
T. Letia, A. Astilean, M. Hulea, ”Real-time control based on feasibility”, Proceedings of 6th International Carpatian Control Conference, Miskolc-Lillafured, Hungary, 2005, vol. 2, pp. 114-120.
A. Astilean, T. Letia, M. Hulea, H. Valean, ”Hierarchical routing system embedded in an urban driving advisory system”, Proceedings of 6th International Carpatian Control Conference, Miskolc-Lillafured, Hungary, 2005, vol.1, pp. 331-336.
Research description
Control and Guidance System for Urban Vehicle Traffic
The main goal of the project is to improve the urban vehicle traffic with the direct effect on the reducing of travelling duration, the environment pollution, the fuel consumption and the increasing of the participants’ comfort by adding new functions. Another goal is to avoid the congestions or at least to delay them and to decrease their effects if they appear.
The proposed control system has a concurrent implementation and some temporal requirements are imposed. The control system is based on the management of the critical resources (represented by the squares inside intersections and lane capacities). Their inadequate management leads to traffic congestions and only decisions related to the resources’ allocation can avoid or delay these undesired situations.
Because the information provided to drivers by traffic lights is insufficient, the introduction of a new informational level is proposed. This can be implemented using the mobile telephony. The guidance system is based on the Global Positioning System and can be accessed using the current available devices. In this way, another function of the intelligent vehicle is achieved. The new guidance system has the purpose to help avoid or delay traffic congestions. The information system can also be used to eliminate the congestions when they appear as consequences of some traffic events by providing the driver with new routes taking into account the current situations.
The study used the preemption based control of urban vehicle traffic. The urban vehicle traffic flows are considered similar to threads of instructions (or software tasks) to be executed by a processor. An intersection is similar to a computer processor that has to transfer (process) vehicle streams (instead of threads of instructions or software tasks). Like the software threads, the urban vehicle flows have period, crossing durations, arrival times, jitters, etc.
Unlike previous vehicle traffic approaches, the current research introduced the pre-emption of the right of crossing through an intersection and was based on the worst case behaviour (or crossing durations) of the system instead of probable vehicle traffic rates. This involves the usage of the highest accepted demands and the highest requirements relative to the timeliness, in design instead of their corresponding probable values.
The proposed approach uses the real-time scheduling methods to signal control of the traffic lights in urban vehicle traffic. The vehicle flows on the lanes associated to an intersection phase are considered similar with the stream of instructions (of a task). Each vehicle stream has its own period (that can be different from the periods of other phases of the same intersection) and duration to cross the intersection. The scheduling parameters are used to test fulfilment of the timing requirements.
Using different periods for the phases of the same intersection, unlike the classical approach of urban vehicle traffic control, solves the need of the correlation of the periods of phases linked in a path. Some studies have been developed to find the effect of modification of phase periods when failures appear. This leads to a kind of dependable urban vehicle traffic.
The local priorities were used to schedule the phase opening and to analyze the feasibility of critical resources scheduling. The global priorities were used to determine the global behavior of the traffic system. They serve to maintain the
main features of the system when failures appear. The relations between global priorities and some quantitative criteria (for traffic performance evaluation) were used to study the possible improvement of traffic system dependability.
A new type of simulator was constructed with the aim to analyze the system behaviour and to verify the proposed solutions. The simulator is able to evaluate the congestion degree taking into account the vehicles that remain inside intersections after their corresponding phases lose the crossing rights (shown to drivers by the green lights). The simulator was used to compare the proposed approach with some classical methods used in vehicle traffic control as extended green.