过饱和路口交通信号控制动态规划优化模型

发布时间：2018-10-22 14:50

【摘要】：社会经济的发展、机动化水平的不断提高使得城市道路交通拥堵日益严重,早晚高峰期交通流经常呈现饱和状态和过饱和状态。交通拥堵往往造成出行延误增加、旅行时间可靠性降低、速度降低,严重制约着城市发展和居民生活水平提高。研究饱和状态和过饱和状态下交通流特征,运用交通管理控制方法缓解交通拥堵、提高道路通行能力成为当务之急。一方面,城市道路交通状态持续动态变化,目前发展的基于视频检测的车牌识别技术能够实时获取车辆行驶路径、延误、旅行时间等详细信息,为精细化交通管控提供基础。另一方面,交通控制方案取决于之前周期的交通状态和当前驶入驶出流量,基于每一阶段的最优控制决策获得该阶段的最优交通状态,为下一阶段交通控制决策提供基础。因此信号控制系统可离散为多步决策过程,以更好的适应交通运行状况及环境的变化。本文首先回顾了过饱和交通流、动态规划交通控制的发展历程和存在问题,对车流离散几何分布模型进行修正,结合转向比、车流消散率、车流离散情况预测车流到达率,分析过饱和交通状态的成因和控制策略,交通控制从增加交通供给和控制交通需求两方面增加通行能力、控制排队长度,实现交叉口供求平衡。然后提出基于动态规划的过饱和单交叉口信号控制优化模型,其中不饱和流以最小化延误、饱和流和过饱和流以最大化通行能力为控制目标,通过迭代运算判断保持或者切换当前相位,并将控制效果实时反馈调节下一阶段配时方案。针对过饱和交通状态下干线协调控制,提出传统协调控制参数与动态规划结合的协调控制配时方法及结合车流到达率和动态规划的动态规划优化配时方法。通过车流到达率和消散率对排队和延误不断进行预测估计,将控制效果实时反馈调节下一阶段配时方案。基于实际采集数据,通过案例计算验证动态规划信号控制模型优化流程,利用matlab实现动态规划模型并获得优化结果,与TRANSYT(Traffic Network Study Tool)系统优化配时方案进行了对比分析。结果表明过饱和交通状态动态规划交通控制有效降低饱和度,减少延误。
[Abstract]:With the development of social economy and the improvement of motorization level, urban road traffic congestion is becoming more and more serious, and the peak traffic flow often presents saturation and supersaturation state in the morning and evening. Traffic jams often lead to increased travel delays, lower reliability of travel time and lower speed, which seriously restricts the development of cities and the improvement of residents' living standards. It is urgent to study the characteristics of traffic flow under saturated and supersaturated conditions, and to use traffic management and control methods to alleviate traffic congestion and improve traffic capacity. On the one hand, the status of urban road traffic continues to change dynamically. Currently, the vehicle license plate recognition technology based on video detection can obtain the detailed information of vehicle travel path, delay, travel time and so on in real time, which provides the basis for fine traffic control. On the other hand, the traffic control scheme depends on the traffic state of the previous period and the current traffic flow. Based on the optimal control decision of each stage, the optimal traffic state of this stage is obtained, which provides the basis for the next stage of traffic control decision. Therefore, the signal control system can be discretized as a multi-step decision-making process to better adapt to traffic conditions and environmental changes. In this paper, the development history and existing problems of supersaturated traffic flow and dynamic programming traffic control are reviewed firstly, and the discrete geometric distribution model of vehicle flow is modified to predict the arrival rate of vehicle flow in combination with steering ratio, vehicle flow dissipation rate and vehicle flow dispersion. The causes and control strategies of oversaturated traffic state are analyzed. Traffic control can increase traffic capacity and control traffic demand by increasing traffic supply and controlling traffic demand, controlling queue length and achieving balance between supply and demand at intersections. Then an optimal signal control model based on dynamic programming for supersaturated single intersection is proposed, in which the unsaturated flow minimizes delay, and the maximum capacity of saturated flow and supersaturated flow is the control objective. The current phase is maintained or switched by iterative operation, and the control effect is real-time feedback to adjust the next phase timing scheme. Aiming at the coordinated control of trunk line under the condition of supersaturated traffic, this paper presents a coordinated control timing method combining traditional coordinated control parameters with dynamic programming, and a dynamic programming optimal timing method combining the arrival rate of vehicle flow and dynamic programming. Traffic arrival rate and dissipation rate are used to predict the queue and delay, and the control effect is real-time feedback to adjust the next stage timing scheme. Based on the actual data collected, the optimization process of dynamic programming signal control model is verified by case calculation. The dynamic programming model is realized by matlab and the optimized results are obtained. The optimized timing scheme of TRANSYT (Traffic Network Study Tool) system is compared with that of TRANSYT (Traffic Network Study Tool) system. The results show that oversaturated traffic dynamic programming can effectively reduce saturation and delay.
【学位授予单位】：清华大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U491.54

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