A simple dynamic model in physical coordinates and the corresponding parameter estimation procedu... more A simple dynamic model in physical coordinates and the corresponding parameter estimation procedure for the primary circuit dynamics and premodeling studies of the secondary circuit of VVER-type pressurized water reactors are presented in this paper. The primary uses of the model are control oriented dynamic model analysis and high level controller design. Therefore, the model should contain the minimal possible number of differential equations and it should be capable of describing important dynamic phenomena such as load change transients between day and night periods. Furthermore, the estimated parameter values should fall into physically meaningful ranges. The parameter estimation method of the primary circuit is an optimization based numerical method using the decomposed and the entire primary circuit model. The partial verification of the models of parts of the secondary circuit has also been completed using badly sampled measurments. The constructed model satisfies the predefined requirements and its response shows good fit to the measurement data that were obtained from three units of the Paks Nuclear Power Plant in Hungary.
Certain variables of dynamic system can not be measured, however they play an important role for ... more Certain variables of dynamic system can not be measured, however they play an important role for control system strategies. In such a situation the approximation, computer based simulation of these variables could be useful for further techniques. There are some estimation methods which can determine the traffic flow in a traffic network. Based on the knowledge of these values, the simulation of the turning rates can be made. The paper treats the simulation of split rates in the traffic systems modelled in terms of linear time varying system using different filtering approaches. The paper proposes three methods for simulation of turning rates in a basic traffic network. First the unconstrained Kalman filtering, and secondly the algorithm that has been developed for traffic systems is based on the unconstrained and constrained Moving Horizon Estimation(MHE) is presented. The constrained MHE problem for traffic systems is modelled in terms of linear time varying system and solves the split rate estimation process. The estimation is subjected to equality and inequality constraints. A numerical example is solved to demonstrate the Moving Horizon Estimation of split variables.
A kutatás célja különböző eljárások vizsgálata a körforgalmak honnan-hová forgalmainak meghatároz... more A kutatás célja különböző eljárások vizsgálata a körforgalmak honnan-hová forgalmainak meghatározásához fordulási arányok becslése alapján.
The testing of Connected and Automated Vehicles (CAVs) and that of the smart infrastructure (traf... more The testing of Connected and Automated Vehicles (CAVs) and that of the smart infrastructure (traffic control devices and vehicle sensors) in relation with CAVs will be supported by the development of a novel type of road traffic light management system at ZalaZONE Automotive Proving Ground. The system to be developed aims to allow a fully flexible traffic signal control during vehicle and system testing. The system shall provide a freely programmable open Application Programming Interface (API) towards the traffic light control units in contrast with traditional (rigid and closed) traffic control equipments. In this concept, each traffic light control unit will be made available via a remote control software running on a cloud system.
The present paper’s focus is the V2X (Vehicle-to-Everything) communication between traffic light ... more The present paper’s focus is the V2X (Vehicle-to-Everything) communication between traffic light controller and road vehicles. After a brief review on the state-of-the-art V2X communication technologies and their feasibility for practical implementation, a brief description of their potential is discussed providing a working solution for SPaT/MAP (Signal Phase and Timing and MAP as intersection geometry) standard based communication, specifically for automotive proving ground usage. The main outcome of the proposed solution is a full y flexible traffic control system applying industrial PLC while ensuring a standardized V2X protocol. As a demonstrative HiL (Hardware-in-the-Loop) example, exploiting the elements of the traffic management system at the ZalaZONE Automotive Proving Ground, a GLOSA (Green Light Optimal Speed Advisory) scenario is presented with the developed SPaT/MAP V2X communication realizing a global optimum traffic control solution. The more, the whole framework is designed in a way that it is capable of using mixed reality components for testing purposes and realizing a digital twin for traffic lights. The method of virtualization for V2X communication is introduced using a co-simulation framework of three common software tools (SUMO, Veins, and OMNeT++).
Road traffic congestion has become an everyday phenomenon in today's cities all around th... more Road traffic congestion has become an everyday phenomenon in today's cities all around the world. The reason is clear: at peak hours, the road network operates at full capacity. In this way, growing traffic demand cannot be satisfied, not even with traffic-responsive signal plans. The external impacts of traffic congestion come with a serious socioeconomic cost: air pollution, increased travel times and fuel consumption, stress, as well as higher risk of accidents. To tackle these problems, a number of European cities have implemented reduced speed limit measures. Similarly, a general urban speed limit measure is in preparatory phase in Budapest, Hungary. In this context, a complex preliminary impact assessment is needed using a simulated environment. Two typical network parts of Budapest were analyzed with microscopic traffic simulations. The results revealed that speed limits can affect traffic differently in diverse network types indicating that thorough examination and preparation works are needed prior to the introduction of speed limit reduction.
A set-theoretical approach is presented for a multi-objective control design of the local ramp me... more A set-theoretical approach is presented for a multi-objective control design of the local ramp metering problem. Two control objectives are specified: first, the optimization of traffic performance, by the minimization of total time spent. Second, the emission factor of CO2 is minimized. The optimal state for traffic emission however lies in the unstable domain of the system. To resolve this inconsistency, the control problem is formalized in a set-theoretical context. For this purpose, the nonlinear METANET model is rewritten in a shifted coordinate frame in a parameter-varying, polytopic representation. Bounds on state-, input-and disturbance variables are expressed by convex polytopes. These sets are then used for the design of an interpolated H∞ controller that is capable of improving traffic conditions according to the prescribed multi-objective criteria. Different control allocation methods are compared with non-linear model predictive control stategy, in order to illustrate the proposed methodology.
Budapesti sebességkorlátozások változtatásának hatásvizsgálata forgalomszimulációval A közúti köz... more Budapesti sebességkorlátozások változtatásának hatásvizsgálata forgalomszimulációval A közúti közlekedési torlódások mára gyakorlatilag mindennapossá váltak a nagyvárosok útjain a világ minden táján. A jelenség magyarázata egyértelmű: a közlekedési hálózatok kapacitása csúcsidőben telítődik, így a fokozódó igények nem szolgálhatók ki megfelelően még akkor sem, ha pl. forgalomfüggő jelzőlámpás irányítás működik. A helyzet javításán többféle módszerrel kísérleteznek, többféle módszerrel kísérleteznek, pl. sebességkorlátozás alkalmazásával. A cikk ezen intézkedési lehetőség hatásvizsgálatával foglalkozik.
In the near future, autonomous vehicles will face with new challenges in several fields. One of t... more In the near future, autonomous vehicles will face with new challenges in several fields. One of the most exciting changes will be represented by the network-wide optimal traffic control. When driverless vehicles take over the road, classical road signalization schemes will become superfluous. Accordingly, the paper's aim is to propose a control design methodology for autonomous vehicles in urban traffic network by considering the network-wide performance. The proposed two-level control strategy solves a tractable optimization problem for a network wide traffic control. On the one hand, a local intersection controller is designed which ensures safe crossings of vehicles and aims to reduce traffic emission in the junction area. On the other hand, the local controllers also optimize the network performance by minimizing the queues in all road links. The traffic is therefore modeled in a two-level fashion. A microscopic dynamics is considered in junctions and macroscopic model is applied for the whole traffic network. The control strategy is tested and evaluated based on microscopic traffic simulation.
International Journal of Computer Integrated Manufacturing, 2018
ABSTRACT Nowadays transportation represents an important field for CPS applications due to the ra... more ABSTRACT Nowadays transportation represents an important field for CPS applications due to the rapid development of highly automated or autonomous vehicles, e.g. warehouse vehicles, airport people movers, public transport, etc. These vehicles are usually designed to circulate on fixed routes independently of the actual state of the network in order to fulfil a given criterion, such as traveling on the shortest path or including scheduled stops. This paper introduces a routing approach that allows automated vehicles to travel on different paths between given points, minimising the generalised cost of the route. Between fixed points, which can be either different storage points in a warehouse or simply public transport stops, possible routes are modelled as a continuously updated weighted directed graph. The weights represent relevant parameters of links, collected from surrounding sensors and monitoring systems of the network. Route optimisation is done by Yen’s algorithm depending on the timetable: if the vehicle will reach the next stop on time, the alternative with the lowest generalised cost is chosen; else the fastest route is followed. The method is introduced specifically via the problem of traffic congestion on public transport paths, but can be generalised, e.g. any transport system within factories or warehouses.
A simple dynamic model in physical coordinates and the corresponding parameter estimation procedu... more A simple dynamic model in physical coordinates and the corresponding parameter estimation procedure for the primary circuit dynamics and premodeling studies of the secondary circuit of VVER-type pressurized water reactors are presented in this paper. The primary uses of the model are control oriented dynamic model analysis and high level controller design. Therefore, the model should contain the minimal possible number of differential equations and it should be capable of describing important dynamic phenomena such as load change transients between day and night periods. Furthermore, the estimated parameter values should fall into physically meaningful ranges. The parameter estimation method of the primary circuit is an optimization based numerical method using the decomposed and the entire primary circuit model. The partial verification of the models of parts of the secondary circuit has also been completed using badly sampled measurments. The constructed model satisfies the predefined requirements and its response shows good fit to the measurement data that were obtained from three units of the Paks Nuclear Power Plant in Hungary.
Certain variables of dynamic system can not be measured, however they play an important role for ... more Certain variables of dynamic system can not be measured, however they play an important role for control system strategies. In such a situation the approximation, computer based simulation of these variables could be useful for further techniques. There are some estimation methods which can determine the traffic flow in a traffic network. Based on the knowledge of these values, the simulation of the turning rates can be made. The paper treats the simulation of split rates in the traffic systems modelled in terms of linear time varying system using different filtering approaches. The paper proposes three methods for simulation of turning rates in a basic traffic network. First the unconstrained Kalman filtering, and secondly the algorithm that has been developed for traffic systems is based on the unconstrained and constrained Moving Horizon Estimation(MHE) is presented. The constrained MHE problem for traffic systems is modelled in terms of linear time varying system and solves the split rate estimation process. The estimation is subjected to equality and inequality constraints. A numerical example is solved to demonstrate the Moving Horizon Estimation of split variables.
A kutatás célja különböző eljárások vizsgálata a körforgalmak honnan-hová forgalmainak meghatároz... more A kutatás célja különböző eljárások vizsgálata a körforgalmak honnan-hová forgalmainak meghatározásához fordulási arányok becslése alapján.
The testing of Connected and Automated Vehicles (CAVs) and that of the smart infrastructure (traf... more The testing of Connected and Automated Vehicles (CAVs) and that of the smart infrastructure (traffic control devices and vehicle sensors) in relation with CAVs will be supported by the development of a novel type of road traffic light management system at ZalaZONE Automotive Proving Ground. The system to be developed aims to allow a fully flexible traffic signal control during vehicle and system testing. The system shall provide a freely programmable open Application Programming Interface (API) towards the traffic light control units in contrast with traditional (rigid and closed) traffic control equipments. In this concept, each traffic light control unit will be made available via a remote control software running on a cloud system.
The present paper’s focus is the V2X (Vehicle-to-Everything) communication between traffic light ... more The present paper’s focus is the V2X (Vehicle-to-Everything) communication between traffic light controller and road vehicles. After a brief review on the state-of-the-art V2X communication technologies and their feasibility for practical implementation, a brief description of their potential is discussed providing a working solution for SPaT/MAP (Signal Phase and Timing and MAP as intersection geometry) standard based communication, specifically for automotive proving ground usage. The main outcome of the proposed solution is a full y flexible traffic control system applying industrial PLC while ensuring a standardized V2X protocol. As a demonstrative HiL (Hardware-in-the-Loop) example, exploiting the elements of the traffic management system at the ZalaZONE Automotive Proving Ground, a GLOSA (Green Light Optimal Speed Advisory) scenario is presented with the developed SPaT/MAP V2X communication realizing a global optimum traffic control solution. The more, the whole framework is designed in a way that it is capable of using mixed reality components for testing purposes and realizing a digital twin for traffic lights. The method of virtualization for V2X communication is introduced using a co-simulation framework of three common software tools (SUMO, Veins, and OMNeT++).
Road traffic congestion has become an everyday phenomenon in today's cities all around th... more Road traffic congestion has become an everyday phenomenon in today's cities all around the world. The reason is clear: at peak hours, the road network operates at full capacity. In this way, growing traffic demand cannot be satisfied, not even with traffic-responsive signal plans. The external impacts of traffic congestion come with a serious socioeconomic cost: air pollution, increased travel times and fuel consumption, stress, as well as higher risk of accidents. To tackle these problems, a number of European cities have implemented reduced speed limit measures. Similarly, a general urban speed limit measure is in preparatory phase in Budapest, Hungary. In this context, a complex preliminary impact assessment is needed using a simulated environment. Two typical network parts of Budapest were analyzed with microscopic traffic simulations. The results revealed that speed limits can affect traffic differently in diverse network types indicating that thorough examination and preparation works are needed prior to the introduction of speed limit reduction.
A set-theoretical approach is presented for a multi-objective control design of the local ramp me... more A set-theoretical approach is presented for a multi-objective control design of the local ramp metering problem. Two control objectives are specified: first, the optimization of traffic performance, by the minimization of total time spent. Second, the emission factor of CO2 is minimized. The optimal state for traffic emission however lies in the unstable domain of the system. To resolve this inconsistency, the control problem is formalized in a set-theoretical context. For this purpose, the nonlinear METANET model is rewritten in a shifted coordinate frame in a parameter-varying, polytopic representation. Bounds on state-, input-and disturbance variables are expressed by convex polytopes. These sets are then used for the design of an interpolated H∞ controller that is capable of improving traffic conditions according to the prescribed multi-objective criteria. Different control allocation methods are compared with non-linear model predictive control stategy, in order to illustrate the proposed methodology.
Budapesti sebességkorlátozások változtatásának hatásvizsgálata forgalomszimulációval A közúti köz... more Budapesti sebességkorlátozások változtatásának hatásvizsgálata forgalomszimulációval A közúti közlekedési torlódások mára gyakorlatilag mindennapossá váltak a nagyvárosok útjain a világ minden táján. A jelenség magyarázata egyértelmű: a közlekedési hálózatok kapacitása csúcsidőben telítődik, így a fokozódó igények nem szolgálhatók ki megfelelően még akkor sem, ha pl. forgalomfüggő jelzőlámpás irányítás működik. A helyzet javításán többféle módszerrel kísérleteznek, többféle módszerrel kísérleteznek, pl. sebességkorlátozás alkalmazásával. A cikk ezen intézkedési lehetőség hatásvizsgálatával foglalkozik.
In the near future, autonomous vehicles will face with new challenges in several fields. One of t... more In the near future, autonomous vehicles will face with new challenges in several fields. One of the most exciting changes will be represented by the network-wide optimal traffic control. When driverless vehicles take over the road, classical road signalization schemes will become superfluous. Accordingly, the paper's aim is to propose a control design methodology for autonomous vehicles in urban traffic network by considering the network-wide performance. The proposed two-level control strategy solves a tractable optimization problem for a network wide traffic control. On the one hand, a local intersection controller is designed which ensures safe crossings of vehicles and aims to reduce traffic emission in the junction area. On the other hand, the local controllers also optimize the network performance by minimizing the queues in all road links. The traffic is therefore modeled in a two-level fashion. A microscopic dynamics is considered in junctions and macroscopic model is applied for the whole traffic network. The control strategy is tested and evaluated based on microscopic traffic simulation.
International Journal of Computer Integrated Manufacturing, 2018
ABSTRACT Nowadays transportation represents an important field for CPS applications due to the ra... more ABSTRACT Nowadays transportation represents an important field for CPS applications due to the rapid development of highly automated or autonomous vehicles, e.g. warehouse vehicles, airport people movers, public transport, etc. These vehicles are usually designed to circulate on fixed routes independently of the actual state of the network in order to fulfil a given criterion, such as traveling on the shortest path or including scheduled stops. This paper introduces a routing approach that allows automated vehicles to travel on different paths between given points, minimising the generalised cost of the route. Between fixed points, which can be either different storage points in a warehouse or simply public transport stops, possible routes are modelled as a continuously updated weighted directed graph. The weights represent relevant parameters of links, collected from surrounding sensors and monitoring systems of the network. Route optimisation is done by Yen’s algorithm depending on the timetable: if the vehicle will reach the next stop on time, the alternative with the lowest generalised cost is chosen; else the fastest route is followed. The method is introduced specifically via the problem of traffic congestion on public transport paths, but can be generalised, e.g. any transport system within factories or warehouses.
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Papers by István Varga