城市道路交通系统的动态随机流Petri网建模与分析

Modeling of Urban Traffic System Based on Dynamic Stochastic Fluid Petri Net

城市道路交通系统是一个同时具有离散和连续动态,并包含大量随机不确定因素的动态系统,具有动态、并发及同步等特征.在目前交通状况日益复杂的情况下,其动态及随机不确定特性愈加明显.对城市道路交通系统进行建模分析,是深入了解交通状况、进行交通诱导及控制的关键.本文在基本Petri网的基础上,将广义随机Petri网(GSPN)与交通流概念相结合,建立了符合交通流概念的动态流随机Petri网(FSPN)模型.该模型可以很好地描述城市道路交通流的动态及随机特性,并能对城市道路交通系统中的某些随机现象作出很好的解析描述.文中针对四相位十字交叉口给出了动态流随机Petri网建模实例;活性分析表明,该模型能有效避免系统并发性带来的死锁现象.最后仿真运行分析和性能分析进一步证明了动态流随机Petri网的有效性.

Urban traffic system,which is characterized by dynamics,concurrence,and synchronization,is a hybrid dynamic stochastic system involving discrete and continuous behaviors.Modeling and analyzing the urban traffic system is the key to deeply understand the whole traffic and to better guide and control of urban traffic system,especially under the current traffic status characterized by frequent congestion and considerable complexity.The study proposed the dynamic stochastic fluid Petri net（DSFPN） with well mathematical analysis ability,which provided a good description of the dynamic and stochastic character of the urban traffic system.The dynamic attributes and the stochastic actions of urban traffic system can be modeled by DSFPN.Then an example of an intersection are modeled and presented in this paper.The simulation and performance analysis of urban traffic system model is introduced to indicate the validity of the DSFPN.