Research and Application of Traffic Network Model on Urban Road with Hybrid Petri Nets
|Course||Traffic Information Engineering \u0026 Control|
|Keywords||Urban transport system Hybrid Systems Hybrid Petri nets Traffic flow model Markov process|
With the accelerated process of urbanization and the popularity of the vehicle, the problem of traffic congestion has become increasingly serious, this is a direct result of an increase in the time wasted on the road, and serious environmental pollution, the huge economic losses. Very limited space available for expansion of roads within the city, and therefore efficient traffic forecasting and traffic control is very necessary. The urban transport system is a typical hybrid systems, including traffic lights dynamic discrete traffic flow dynamics is continuous, and the interaction between each cross-Man mouth semaphores dynamic and traffic flow dynamic. This paper attempts to use hybrid Petri nets (HPN) modeling of the transport system, combined with the actual design of several applications of the model. Hybrid Petri nets is a graphical modeling tool, which makes the model more intuitive and easy to understand, and rigorous mathematical analysis theory. The paper designs the discrete part of the hybrid Petri nets used to characterize the signal light dynamic, continuous part used to characterize the traffic flow dynamic. Firstly, given the theoretical foundation of Petri nets and hybrid Petri nets; then analyze the physical model of the urban transport system in the intersection and slip, and to cross the intersection of two, four two phases based, with built mold tool Visual Object Net phase two, four HPN model transportation network is composed by a number of intersections and multi-branch, each intersection HPN model including all branches of the intersection and composition of the intersection way, so the entire transport network HPN model by each intersection HPN model; Finally, in order to illustrate the practical value of the the city intersections HPN model, the paper of the most common cross intersections, for example, HPN model test , and in the application of three exploration. The first application is a short-term traffic flow forecast, including the introduction of a Markov process, after the perfection of the Markov process, the intersection of hybrid Petri nets model can predict the green signal cycle according to traffic conditions; second point applications HPN model outside the presence of dynamic traffic assessment, based on the relative error between the model derived from simulation of traffic flow and the actual traffic flow is zero, whether there is a dynamic traffic judgment model; third point of application of the exact measured values ??for the protection of traffic The urban traffic measurement system failure will result in online control can not be normal, papers HPN model of the measured data to be improved. Hybrid Petri nets fully reflects the hybrid nature of the transport system of the urban traffic system modeling method, thesis research, analysis of urban traffic prediction, control and improvement of urban congestion provide theoretical and technical support.