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为研究城市主干道交通信号协调优化问题,建立了包括交叉口交通信号显示模块与信号相位转换模块的时延Petri网模型与基于变速度连续Petri网的交通流模型,设计了由监控、判别和通行相位选择3个子系统构成的交通信号控制系统,并给出了具体的控制步骤。根据连续Petri网中各参数间的关系,以车辆排队长度、上游路段车流速度和下游路段畅通度为输入变量,以相位优先指数为输出变量,确定下一通行相位,采用模糊Petri网确定当前相位的最佳绿灯时间,并进行了仿真计算。仿真结果表明:采用Petri网与模糊控制相结合的方法后,由西向东与由东向西方向车流的行程时间分别缩短了7.1%、7.6%,交叉口排队长度的改进率分别为11.9%、11.2%,4个相位的交叉口平均延误分别由9.7、10.3、11.8、13.2s下降到8.2、9.1、11.4、11.4s。可见,主干道信号协调优化方法可以较好地实现干线信号协调控制。
In order to study the coordinated optimization of traffic signals in urban arterial roads, a time-delay Petri net model including traffic signal display module and signal phase conversion module and a traffic flow model based on variable speed continuous Petri net are established. Traffic phase selection of three subsystems traffic signal control system, and gives the specific control steps. According to the relationship among the parameters in continuous Petri nets, the queue length of vehicles, the traffic speed of the upstream road and the smoothness of the downstream road are taken as the input variables, the phase priority index is taken as the output variable, the next passing phase is determined, and the fuzzy Petri net is used to determine the current phase The best green light time, and conducted a simulation. The simulation results show that the travel time of traffic flow from west to east and from east to west is shortened 7.1% and 7.6% respectively by adopting the combination of Petri net and fuzzy control, and the improvement rates of the queue length at the intersection are respectively 11.9% 11.2%. The average delay of intersections of 4 phases decreased from 9.7, 10.3, 11.8 and 13.2s to 8.2, 9.1, 11.4 and 11.4s respectively. Can be seen, the main road signal coordination and optimization methods can be better trunk signal coordination control.