CN102289943A

CN102289943A - Traffic control method for ensuring smoothness of fly-over crossing

Info

Publication number: CN102289943A
Application number: CN2011101805216A
Authority: CN
Inventors: 董红召; 马帅; 郭明飞; 陈宁
Original assignee: Zhejiang University of Technology ZJUT
Current assignee: Zhejiang University of Technology ZJUT
Priority date: 2011-06-29
Filing date: 2011-06-29
Publication date: 2011-12-21

Abstract

A kind of traffic control method that guarantees viaduct unimpeded, comprises the following steps: (1) establish viaduct main line real-time traffic state model: install signal light, traffic flow detector at each ramp entrance and ramp exit, described signal light and traffic flow detector are all Connect with the signal control server; a viaduct is divided into N controllable units by the ramp, N is a natural number, and the main line section of the viaduct between two adjacent ramps is determined as a controllable unit; (2) Based on traffic capacity-saturation (3) On-ramp control process: The cycle of the on-ramp regulation signal of the controllable unit i has two phases, that is, there are green lights and red lights for allowing vehicles to enter the viaduct and forbidding vehicles to enter the viaduct respectively Indicates that the base determines the green light time t _g and the red light time in the time period [KT, (K+1)t]. The invention has good real-time performance, good control effect and good adaptability.

Description

A traffic control method to ensure the smooth flow of viaducts

技术领域 technical field

本发明涉及交通控制方法，尤其是一种高架桥交通控制方法。The invention relates to a traffic control method, in particular to a viaduct traffic control method.

背景技术 Background technique

随着城市化速度的加快，机动车日益普及，人们在享受机动车带来的便利的同时，也面临交通拥堵的困惑。因此在现有道路条件下，实施有效的交通控制方法，合理使用现有交通设施，充分发挥其能力，是解决交通问题的有效方法之一。With the acceleration of urbanization and the increasing popularity of motor vehicles, people are also facing the confusion of traffic congestion while enjoying the convenience brought by motor vehicles. Therefore, under the existing road conditions, implementing effective traffic control methods, rationally using existing traffic facilities, and giving full play to their capabilities are one of the effective ways to solve traffic problems.

城市发展后，交通拥挤，建筑物密集，而街道又难于拓宽，平面立交的道口造成车辆的堵塞和拥挤，已经不能满足人们日常出行需求，因此通过修建高架桥可以形成多层立体的布局，以提高车速和通行能力，疏散交通密度，提高城市路网运输效率。城市高架立交桥已成为现代化城市的重要标志，广泛应用于城市道路中的交通繁忙地段。After the development of the city, the traffic is congested, the buildings are dense, and the streets are difficult to widen. The intersections of the level interchanges cause vehicle congestion and congestion, which can no longer meet people's daily travel needs. Therefore, a multi-layer three-dimensional layout can be formed by building viaducts to improve Vehicle speed and traffic capacity, evacuation of traffic density, and improvement of urban road network transportation efficiency. Urban viaducts have become an important symbol of modern cities and are widely used in busy traffic areas on urban roads.

城市高架桥一般道路等级为城市快速路，具有连续流，大容量，饱和流等交通特性，但城市高架桥面对持续增加的大流量，期望的畅通，快速效果迅速弱化，道路拥堵问题依旧严峻。以杭州的中河-上塘高架为例，全长20.3公里，沿线设5座互通立交及25对匝道，路宽19米，双向四车道，设计断面的最高通行能力为2200辆/小时，但近期据交通管理部门的数据统计，白天7:00-19:00的平均车流量超过3000辆/小时，其中早高峰期间最大的流量可达4000辆/小时，如此大流量，已让高架桥不堪重负，并车流的行驶速度骤降，拥堵问题严峻，因此迫切需要一种保证高架桥畅通的有效交通控制方法。The general road level of urban viaducts is urban expressways, which have traffic characteristics such as continuous flow, large capacity, and saturated flow. However, in the face of continuously increasing large traffic, urban viaducts are expected to be smooth and fast. The effect is rapidly weakened, and the problem of road congestion is still severe. Take the Zhonghe-Shangtang elevated highway in Hangzhou as an example. It has a total length of 20.3 kilometers. There are 5 interchanges and 25 pairs of ramps along the line. The road is 19 meters wide and has two-way four-lane roads. According to statistics from the traffic management department, the average traffic flow from 7:00 to 19:00 in the daytime exceeds 3,000 vehicles/hour, and the maximum flow rate during the morning rush hour can reach 4,000 vehicles/hour. Such a large flow has overwhelmed the viaduct. The driving speed of the parallel traffic flow drops sharply, and the problem of congestion is severe, so there is an urgent need for an effective traffic control method to ensure the smooth flow of the viaduct.

入口匝道控制作为缓解高架桥拥堵的有效方法之一。入口匝道控制的原理：通过调节入口匝道进入高架桥的交通流量，使高架桥的主线的交通流饱和度处于一定服务水平，从而使高架桥主线交通运行在最佳的状态，满足出行者的出行要求。目前入匝道控制方法主要采用定时控制：该类方法采用固定的控制策略或者根据一天内不同时段预设不同的控制策略，属于非实时控制方法，存在一定的局限性，适应性较弱，控制效果一般。On-ramp control is one of the effective methods to relieve viaduct congestion. The principle of on-ramp control: By adjusting the traffic flow of the on-ramp entering the viaduct, the traffic flow saturation of the main line of the viaduct is at a certain service level, so that the traffic on the main line of the viaduct runs in the best state and meets the travel requirements of travelers. At present, the on-ramp control method mainly adopts timing control: this type of method adopts a fixed control strategy or presets different control strategies according to different periods of the day, and belongs to the non-real-time control method, which has certain limitations, weak adaptability, and poor control effect. generally.

发明内容 Contents of the invention

为了克服已有高架桥交通控制方法的实时性差、控制效果较差、适应性较弱的不足，本发明提供一种实时性良好、控制效果良好、适应性较好的保证高架桥畅通的交通控制方法。In order to overcome the shortcomings of poor real-time performance, poor control effect and weak adaptability of existing viaduct traffic control methods, the present invention provides a traffic control method with good real-time performance, good control effect and good adaptability to ensure the smooth flow of viaducts.

本发明解决其技术问题所采用的技术方案是：The technical solution adopted by the present invention to solve its technical problems is:

一种保证高架桥畅通的交通控制方法，所述交通控制方法包括以下步骤：A kind of traffic control method that guarantees viaduct unimpeded, described traffic control method comprises the following steps:

(1)建立高架桥主线实时交通状态模型：(1) Establish a real-time traffic status model for the main line of the viaduct:

在每个匝道入口和匝道出口安装信号灯、交通流量检测器，所述信号灯和交通流量检测器均与信号控制服务器连接；Signal lights and traffic flow detectors are installed at each ramp entrance and ramp exit, and the signal lights and traffic flow detectors are all connected to the signal control server;

一条高架桥被匝道分隔成N个可控单元，N为自然数，以每相邻两个匝道之间的高架桥主线路段确定为一可控单元，每个可控单元路段的长度Δ_i，i＝1，2，...，N，路段交通流运行状态作为控制对象，采样周期为T，连续时间离散化后，t为采样时间，t＝kT，k＝1，2，...，K，第i路段交通流量、交通密度和平均速度分别q_i(k)，ρ_i(k)，v_i(k)，其入口和出口匝道流量分别记为r_i(k)，s_i(k)A viaduct is divided into N controllable units by ramps, N is a natural number, the main line section of the viaduct between two adjacent ramps is determined as a controllable unit, and the length of each controllable unit section is _Δi , i=1 . The traffic flow, traffic density and average speed of the i-th road segment are respectively q _i (k), ρ _i (k), v _i (k), and the entrance and exit ramp flows are respectively denoted as r _i (k), s _i (k)

${ρ ρ}_{i i} ((k k + + 11)) = = {ρ ρ}_{i i} ((k k)) + + \frac{T T}{{Δ Δ}_{i i}} [[{q q}_{i i - - 11} ((k k)) - - {q q}_{i i} ((k k)) + + {r r}_{i i} ((k k)) - - {s the s}_{i i} ((k k))]]$

q_i(k)＝αρ_i(k)v_i(k)+(1-α)[ρ_i+1(k)v_i+1(k)-r_i+1(k)]-s_i(k)q _i (k)=αρ _i (k)v _i (k)+(1-α)[ρ _i+1 (k)v _i+1 (k)-r _i+1 (k)]-s _i ( k)

入口匝道的排队长度p_i(k)满足：The queue length p _i (k) of the on-ramp satisfies:

p_i(k+1)＝p_i(k)+T[d_i(k)-r_i(k)]p _i (k+1)=p _i (k)+T[d _i (k)-r _i (k)]

式中，d_i(k)表示入口匝道的到达流量；In the formula, d _i (k) represents the arrival flow of the on-ramp;

所述r_i(k)的约束条件The constraints of the r _i (k)

$max max {{{γ γ}_{i i min min},, {d d}_{i i} ((k k)) - - \frac{11}{T T} [[{p p}_{i i max max} - - {p p}_{i i} ((k k))]]}} \leq \leq {r r}_{i i} ((k k)) \leq \leq min min {{{γ γ}_{i i max max},, {d d}_{i i} ((k k)) + + \frac{11}{T T} {p p}_{i i} ((k k))}}$

式中，γ_imax，γ_imin分别为入口匝道的预设的调节率的上下限值，p_imax为入口匝道i的排队容量；In the formula, γ _imax and γ _imin are the upper and lower limits of the preset adjustment rate of the entrance ramp respectively, and p _imax is the queuing capacity of entrance ramp i;

(2)基于通行能力-饱和度入口的入道匝口自适应控制过程：(2) Adaptive control process of approach ramp based on capacity-saturation entrance:

高架桥可控单元i的实际条件下的通行能力：The traffic capacity of viaduct controllable unit i under actual conditions:

C_i＝C₀×f_CW×f_SW×f_HV C _i ＝C ₀ ×f _CW ×f _SW ×f _HV

C₀表示基本通行能力；C ₀ means basic traffic capacity;

f_CW——行车道宽度对通行能力的修正系数；f _CW ——the correction coefficient of the width of the traffic lane to the traffic capacity;

f_SW——侧向净空对通行能力的修正系数；f _SW — correction coefficient of lateral clearance to traffic capacity;

f_HV——交通组成对通行能力的修正系数；f _HV - the correction coefficient of traffic composition to traffic capacity;

γ(k)表示时段[KT，(K+1)T]内入口匝道调节率，其计算公式为γ(k) represents the adjustment rate of the on-ramp in the time period [KT, (K+1)T], and its calculation formula is

$γ γ ((k k)) = = \{\begin{matrix} {c c}_{i i} \times \times v v / / c c - - {q q}_{i i - - 11} ((k k - - 11)) & {ρ ρ}_{i i} ((k k)) \leq \leq {ρ ρ}_{cr cr} \\ {γ γ}_{min min} & {ρ ρ}_{i i} ((k k)) > > {ρ ρ}_{cr cr} \end{matrix}$

式中，v/c为邻近可控单元的饱和度，ρ_cr为交通密度的临界值；In the formula, v/c is the saturation of adjacent controllable units, and _ρcr is the critical value of traffic density;

(3)入口匝道控制过程：(3) On-ramp control process:

可控单元i入口匝道的匝道调节信号周期有两个相位，即允许车辆进入高架桥和禁止车辆进入高架桥分别有绿灯和红灯表示，基确定在时段[KT，(k+1)T]内绿灯时间t_g和红灯时间t_r：There are two phases in the cycle of the ramp adjustment signal of the controllable unit i entrance ramp, that is, allowing vehicles to enter the viaduct and prohibiting vehicles from entering the viaduct are represented by green lights and red lights respectively, and the base is determined to be green within the time period [KT, (k+1)T] Time t _g and red light time t _r :

${t t}_{g g} = = \frac{36003600 \times \times n no}{γ γ ((k k))}$

${t t}_{r r} = = \frac{{C C}_{i i} - - γ γ ((k k))}{γ γ ((k k))} \times \times {t t}_{g g} = = \frac{[[{C C}_{i i} - - γ γ ((k k))]] 36003600 \times \times n no}{γ γ {((k k))}^{22}}$

n为该周期内允许进入高架桥主线的车辆数，且n＝[ρ_imax-ρ_i(k)]×Δ_i。n is the number of vehicles allowed to enter the main line of the viaduct in this period, and n=[ρ _imax -ρ _i (k)]×Δ _i .

进一步，所述步骤(3)中，在整个信号周期中两个相位的交替期间增加黄灯时间。Further, in the step (3), the yellow light time is increased during the alternation of the two phases in the entire signal cycle.

再进一步，所述交通控制方法还包括以下步骤：Still further, the traffic control method also includes the following steps:

(4)出口匝道邻近地面交叉路口的协调控制：(4) Coordinated control of exit ramps adjacent to ground intersections:

设定出口匝道满溢判断准则q_i(k)-ρ_i(k)×Δ_i-s_i(k-1)≥p_imax(k)，若满足，则触发协调控制，增加邻近地面交叉路口的绿性比；若不满足，则邻近地面交叉路口的绿性比恢复到原始状态。Set the judgment criterion q _i (k)-ρ _i (k)×Δ _i -s _i (k-1)≥p _imax (k) for exit ramp overflow, if satisfied, trigger coordinated control and increase the number of adjacent ground intersections The greenness ratio of ; if it is not satisfied, the greenness ratio of the adjacent ground intersection will be restored to the original state.

本发明的技术构思为：以保证高架桥全局畅通为前提的高架桥快速路出入口匝道控制方法：以每相邻两匝道组成的高架桥主线路段为控制单元，通过交通检测设备实时检测高架桥主线及各个匝道的交通的交通流信息，获取控制单元的实时交通运行状态，通过通行能力-饱和度自适应控制确定实时的入口匝道调节率，并将其作为输入通过预设的模型得到入口匝道控制方案，并实施设置在入口匝道的信号灯和自动收缩门，控制进入高架桥主线的车流量，并与出口匝道邻近地面交叉路口协同控制，使驶离高架桥的车流及时疏散，使主线的交通状态畅通并运行效率达到最高。该交通控制系统由信号灯、信号控制器、交通流检测器、服务器等组成。The technical idea of the present invention is: the viaduct expressway entrance and exit ramp control method based on the premise of ensuring the overall smoothness of the viaduct: the viaduct main line section composed of two adjacent ramps is used as the control unit, and the viaduct main line and each ramp are detected in real time by traffic detection equipment. Traffic flow information of the traffic, obtain the real-time traffic operation status of the control unit, determine the real-time on-ramp regulation rate through the capacity-saturation adaptive control, and use it as input to obtain the on-ramp control scheme through the preset model, and implement The signal lights and automatic retractable doors set on the entrance ramp control the traffic flow entering the main line of the viaduct, and cooperate with the exit ramp adjacent to the ground intersection to evacuate the traffic leaving the viaduct in time, so that the traffic state of the main line is smooth and the operating efficiency reaches the highest . The traffic control system is composed of signal lights, signal controllers, traffic flow detectors, servers and so on.

本发明的有益效果主要表现在：1、实时性良好、控制效果良好、适应性较好；2、不仅能提高高架桥高峰期间的车辆行驶速度，增加高峰期间的交通量，减少交通拥堵和车辆行驶的延误时间，同时能大大减少交通事故和节约能源等，具有显著的社会的效益。The beneficial effects of the present invention are mainly manifested in: 1. Good real-time performance, good control effect, and good adaptability; 2. Not only can the vehicle speed be increased during the peak period of the viaduct, but also the traffic volume during the peak period can be increased, and traffic congestion and vehicle driving can be reduced. At the same time, it can greatly reduce traffic accidents and save energy, etc., which has significant social benefits.

附图说明 Description of drawings

图1是交通控制系统拓扑图。Figure 1 is a topological diagram of the traffic control system.

其中，1——地埋线圈；2——信号灯；3——信号控制器；4——交通数据服务器；5——交通管理中心；6——信号控制服务中心；7——入口匝道；8——高架桥；9——出口匝道；10——地面道路。Among them, 1—buried coil; 2—signal light; 3—signal controller; 4—traffic data server; 5—traffic management center; 6—signal control service center; 7—entrance ramp; 8 - viaduct; 9 - exit ramp; 10 - surface road.

图2是保证高架桥畅通的交通控制方法的流程图。Fig. 2 is a flow chart of the traffic control method for ensuring the smooth flow of the viaduct.

具体实施方式 Detailed ways

下面结合附图对本发明作进一步描述。The present invention will be further described below in conjunction with the accompanying drawings.

参照图1和图2，一种保证高架桥畅通的交通控制方法，所述交通控制方法包括以下步骤：With reference to Fig. 1 and Fig. 2, a kind of traffic control method that guarantees viaduct unimpeded, described traffic control method comprises the following steps:

p_i(k+1)＝p_i(k)+T[d_i(k)-r_i(k)]p _i (k+1)=p _i (k)+T[d _i (k)-r _i (k)]

所述r_i(k)的约束条件The constraints of the r _i (k)

C_i＝C₀×f_CW×f_SW×f_HV C _i ＝C ₀ ×f _CW ×f _SW ×f _HV

C₀表示基本通行能力；C ₀ means basic traffic capacity;

(3)入口匝道控制过程：(3) On-ramp control process:

${t t}_{g g} = = \frac{36003600 \times \times n no}{γ γ ((k k))}$

所述步骤(3)中，在整个信号周期中两个相位的交替期间增加黄灯时间。In the step (3), the yellow light time is increased during the alternation of the two phases in the entire signal cycle.

所述交通控制方法还包括以下步骤：(4)出口匝道邻近地面交叉路口的协调控制：设定出口匝道满溢判断准则q_i(k)-ρ_i(k)×Δ_i-s_i(k-1)≥p_imax(k)，若满足，则触发协调控制，增加邻近地面交叉路口的绿性比；若不满足，则邻近地面交叉路口的绿性比恢复到原始状态。The traffic control method also includes the following steps: (4) Coordinated control of exit-ramp adjacent ground intersections: setting exit-ramp overflow judgment criterion q _i (k)-ρ _i (k)×Δ _i -s _i (k -1)≥p _imax (k), if satisfied, trigger coordinated control to increase the greenness ratio of adjacent ground intersections; if not, restore the greenness ratio of adjacent ground intersections to the original state.

本实施例中，高架桥主线实时交通状态建模：与城市道路交通不同的是：高架桥没有平面交叉口，因而其交通流的是连续的，这一特点与高速公路的交通类似，因此借鉴高速公路交通模型的MACK模型，对高架桥交通流状态进行建模。In this embodiment, the real-time traffic status modeling of the main line of the viaduct is different from the urban road traffic: the viaduct does not have a level intersection, so its traffic flow is continuous, which is similar to the traffic of the expressway, so we learn from the expressway The MACK model of the traffic model, modeling the traffic flow state of the viaduct.

考虑一条高架桥被匝道分隔成N个可控单元，以每相邻两个匝道之间的高架桥主线路段确定为一可控单元，每个可控单元路段的长度Δ_i(i＝1，2，...，N)，路段交通流运行状态作为控制对象，采样周期为T，连续时间离散化后，t＝kT(k＝1，2，...，K)第i路段交通流量、交通密度和平均速度分别q_i(k)，ρ_i(k)，v_i(k)，其入口和出口匝道流量分别记为r_i(k)，s_i(k)。Considering that a viaduct is divided into N controllable units by the ramp, the main line section of the viaduct between two adjacent ramps is determined as a controllable unit, and the length Δ _i of each controllable unit road section (i=1, 2, ..., N), the traffic flow running state of the road section is taken as the control object, the sampling period is T, after continuous time discretization, t=kT (k=1, 2, ..., K) the i-th road section traffic flow, traffic Density and average velocity are q _i (k), ρ _i (k), and v _i (k), respectively, and the on-ramp and off-ramp flows are denoted as r _i (k), s _i (k), respectively.

对于高架桥的首末端，即i＝1和i＝N的情况有For the head and end of the viaduct, i.e. i=1 and i=N, there are

ρ₁(k+1)＝ρ₁(k)，v₁(k+1)＝v[ρ₁(k)]ρ ₁ (k+1)=ρ ₁ (k), v ₁ (k+1)=v[ρ ₁ (k)]

p_i(k+1)＝p_i(k)+T[d_i(k)-r_i(k)]p _i (k+1)=p _i (k)+T[d _i (k)-r _i (k)]

式中，d_i(k)表示入口匝道的到达流量In the formula, d _i (k) represents the arrival flow of the on-ramp

上述状态方程，入口匝道流量r_i(k)约束于入口匝道调节率γThe above equation of state, the on-ramp flow r _i (k) is constrained by the on-ramp adjustment rate γ

γ_imax≥γ_i(k)≥γ_imin γ _imax ≥ γ _i (k) ≥ γ _imin

γ_imax，γ_imin分别为入口匝道的预设的调节率的上下限值。γ _imax and γ _imin are the upper and lower limits of the preset adjustment rate of the entrance ramp respectively.

并且入口匝道i的排队车辆数也不能超过其排队容量p_imax，即And the number of queuing vehicles on entrance ramp i cannot exceed its queuing capacity p _imax , namely

p_i(k)+T[d_i(k)-r_i(k)]≤p_imax p _i (k)+T[d _i (k)-r _i (k)]≤p _imax

显然排队长度p_i(k+1)≥0即Obviously, the queue length p _i (k+1)≥0 is

p_i(k)+T[d_i(k)-r_i(k)]≥0p _i (k)+T[d _i (k)-r _i (k)]≥0

整理得r_i(k)≤d_i(k)+p_i(k)/TArranging r _i (k)≤d _i (k)+p _i (k)/T

综上所述r_i(k)的约束条件To sum up the constraints of r _i (k) mentioned above

基于通行能力-饱和度入口匝道自适应控制：这种控制方法的特征是高架桥的主线的饱和度作为可控参数，在实时控制入口匝道邻近可控单元的饱和度即v/c的基础上并根据可控单元的实时的交通状态确定匝道调节率，其目标是以保证高架桥的畅通的前提下，满足不同时段的道路服务水平，满足出行者的需求。Adaptive control of on-ramp based on capacity-saturation: This control method is characterized by the saturation of the main line of the viaduct as a controllable parameter, based on the real-time control of the saturation of the controllable unit adjacent to the on-ramp, namely v/c, and The ramp adjustment rate is determined according to the real-time traffic status of the controllable unit. The goal is to meet the road service level at different times and meet the needs of travelers on the premise of ensuring the smooth flow of the viaduct.

C_i＝C₀×f_CW×f_SW×f_HV C _i ＝C ₀ ×f _CW ×f _SW ×f _HV

C₀——基本通行能力(pcu/h)，一般

t为最小安全车头时距(s)，设计速度为100km/h、80km/h、60km/h的基本通行能力分别为2200pcu/h/ln、2000pcu/h/ln、1800pcu/h/ln；C ₀ ——basic capacity (pcu/h), general

t is the minimum safe headway (s), and the basic traffic capacities of the design speeds of 100km/h, 80km/h, and 60km/h are 2200pcu/h/ln, 2000pcu/h/ln, and 1800pcu/h/ln respectively;

f_HV——交通组成对通行能力的修正系数。f _HV —the correction coefficient of traffic composition to traffic capacity.

ρ_cr为交通密度的临界值。ρ _cr is the critical value of traffic density.

入口匝道控制方案的设计：入口匝道控制方案包括入口匝道的车道数的调整及入口匝道的信号配时的设计两方面。Design of the on-ramp control scheme: The on-ramp control scheme includes two aspects: the adjustment of the number of lanes on the on-ramp and the design of the signal timing of the on-ramp.

匝道调节率的确定之后，若主线的交通流趋于饱和，调节率偏小时，此时允许进入可控单元的车流量较小，为了避免车辆过多积聚在匝道，较长等待时间容易导致驾驶员焦虑的心理，因此要调整入口匝道的车道数，通过匝道入口的自动收缩门，适时关闭车道，实行单车道通过匝道，同时也是对地面车流中意图进入高架车流起到了一定的警示和提醒作用：当前高架交通流趋于饱和。使其考虑适时选择其他的出行的路径。反之，当主线的交通流较小时，调节率偏大时，此时允许进入主线的车流量较大，因此开启所有匝道上的车道，并行放行车流，缩短进入可控单元的时间，及时高架桥主线道路资源。After the adjustment rate of the ramp is determined, if the traffic flow on the main line tends to be saturated and the adjustment rate is small, the traffic flow allowed to enter the controllable unit is small at this time. In order to avoid excessive accumulation of vehicles on the ramp, a long waiting time will easily lead to driving Therefore, it is necessary to adjust the number of lanes on the entrance ramp, close the lane in due course through the automatic retractable door at the entrance of the ramp, and implement a single lane to pass the ramp. At the same time, it also plays a certain role in warning and reminding the traffic on the ground that intends to enter the elevated traffic flow. : The current elevated traffic flow tends to be saturated. Make it consider choosing other travel paths in due course. Conversely, when the traffic flow on the main line is small and the adjustment rate is too large, the traffic flow allowed to enter the main line is relatively large at this time, so all the lanes on the ramp are opened, the traffic flow is released in parallel, the time to enter the controllable unit is shortened, and the main line of the viaduct is timely road resources.

可控单元i入口匝道的信号配时方案设计，匝道调节信号周期有两个相位，即允许车辆进入高架桥和禁止车辆进入高架桥分别有绿灯和红灯表示，基于入口匝道的调节率这一重要参数，因此要确定在时段[KT，(k+1)T]内绿灯和红灯时间。The signal timing scheme design of the entrance ramp of the controllable unit i, the ramp adjustment signal cycle has two phases, that is, allowing vehicles to enter the viaduct and prohibiting vehicles from entering the viaduct are indicated by green lights and red lights respectively, based on the important parameter of the adjustment rate of the entrance ramp , so it is necessary to determine the time of green light and red light in the time period [KT, (k+1)T].

${t t}_{g g} = = \frac{36003600 \times \times n no}{γ γ ((k k))}$

n为该周期内允许进入高架桥主线的车辆数，且n＝[ρ_imax-ρ_i(k)]×Δ_i，考虑到道路安全，不易引起车流的紊乱，因此在整个信号周期中两个相位的交替期间增加黄灯时间，预设为5秒。n is the number of vehicles allowed to enter the main line of the viaduct in this cycle, and n=[ρ _imax -ρ _i (k)]×Δ _i , considering road safety, it is not easy to cause traffic disturbance, so in the entire signal cycle, two phases Increase the yellow light time during the alternation period, the default is 5 seconds.

4.出口匝道邻近地面交叉路口的协调控制4. Coordinated control of off-ramp adjacent ground intersections

当出口匝道流量s_i(k)处于较高的水平，且在出口匝道排队满溢现象，并导致高架桥主线交织区出现过饱和现象，则需与出口匝道邻近地面交叉路口进行协调控制，适当增加相应进口道的各方向的绿性比，加快出口匝道车流驶离高架桥，避免高架桥道路时空资源的浪费，提高主线的运行效率。When the off-ramp flow s _i (k) is at a relatively high level, and the queuing overflow phenomenon on the off-ramp leads to oversaturation in the weaving area of the main line of the viaduct, it is necessary to coordinate control with the ground intersection adjacent to the off-ramp, and appropriately increase Corresponding to the greenness ratio of each direction of the entrance road, speed up the traffic flow of the exit ramp to leave the viaduct, avoid the waste of time and space resources of the viaduct road, and improve the operating efficiency of the main line.

出口匝道满溢判断准则q_i(k)-ρ_i(k)×Δ_i-s_i(k-1)≥p_imax(k)，若满足这一准则，则触发协调控制：出口匝道车流驶入的交叉口的所属的进口道，并确定该所属该进口道的相位，以该进口的平均延误时间最少为优化控制目标，动态调整周期及所属相位的绿性比。Judgment criterion q _i (k)-ρ _i (k)× _Δi -s _i (k-1)≥p _imax (k) for overflow of off-ramp, if this criterion is satisfied, coordinated control will be triggered: off-ramp traffic flow The entrance lane of the intersection that enters belongs, and the phase of the entrance lane is determined, and the average delay time of the entrance is the least as the optimization control target, and the cycle and the green ratio of the phase are dynamically adjusted.

Claims

1. A traffic control method that guarantees the unimpeded flow of viaduct, is characterized in that: described traffic control method may further comprise the steps:

(1) Establish a real-time traffic status model for the main line of the viaduct:

Signal lights and traffic flow detectors are installed at each ramp entrance and ramp exit, and the signal lights and traffic flow detectors are all connected to the signal control server;

A viaduct is divided into N controllable units by ramps, N is a natural number, the main line section of the viaduct between two adjacent ramps is determined as a controllable unit, and the length of each controllable unit section is _Δi , i=1 . The traffic flow, traffic density and average speed of the i-th road segment are respectively q _i (k), ρ _i (k), v _i (k), and the entrance and exit ramp flows are respectively denoted as r _i (k), s _i (k)

{ρ ρ}_{i i} ((k k + + 11)) = = {ρ ρ}_{i i} ((k k)) + + \frac{T T}{{Δ Δ}_{i i}} [[{q q}_{i i - - 11} ((k k)) - - {q q}_{i i} ((k k)) + + {r r}_{i i} ((k k)) - - {s the s}_{i i} ((k k))]]

q _i (k)=αρ _i (k)v _i (k)+(1-α)[ρ _i+1 (k)v _i+1 (k)-r _i+1 (k)]-s _i ( k)

The queue length p _i (k) of the on-ramp satisfies:

p _i (k+1)=p _i (k)+T[d _i (k)-r _i (k)]

In the formula, d _i (k) represents the arrival flow of the on-ramp;

The constraints of the r _i (k)

max max {{{γ γ}_{i i min min},, {d d}_{i i} ((k k)) - - \frac{11}{T T} [[{p p}_{i i max max} - - {p p}_{i i} ((k k))]]}} \leq \leq {r r}_{i i} ((k k)) \leq \leq min min {{{γ γ}_{i i max max},, {d d}_{i i} ((k k)) + + \frac{11}{T T} {p p}_{i i} ((k k))}}

In the formula, γ _imax and γ _imin are the upper and lower limits of the preset adjustment rate of the entrance ramp respectively, and p _imax is the queuing capacity of entrance ramp i;

(2) Adaptive control process of approach ramp based on capacity-saturation entrance:

The traffic capacity of viaduct controllable unit i under actual conditions:

C _i ＝C ₀ ×f _CW ×f _SW ×f _HV

C ₀ means basic traffic capacity;

f _CW ——the correction coefficient of the width of the traffic lane to the traffic capacity;

f _SW — correction coefficient of lateral clearance to traffic capacity;

f _HV - the correction coefficient of traffic composition to traffic capacity;

γ(k) represents the adjustment rate of the on-ramp in the time period [KT, (k+1)T], and its calculation formula is

γ γ ((k k)) = = \{\begin{matrix} {c c}_{i i} \times \times v v / / c c - - {q q}_{i i - - 11} ((k k - - 11)) & {ρ ρ}_{i i} ((k k)) \leq \leq {ρ ρ}_{cr cr} \\ {γ γ}_{min min} & {ρ ρ}_{i i} ((k k)) > > {ρ ρ}_{cr cr} \end{matrix}

In the formula, v/c is the saturation of adjacent controllable units, and _ρcr is the critical value of traffic density;

(3) On-ramp control process:

There are two phases in the cycle of the ramp adjustment signal of the controllable unit i entrance ramp, that is, allowing vehicles to enter the viaduct and prohibiting vehicles from entering the viaduct are represented by green lights and red lights respectively, and the base is determined to be green within the time period [KT, (k+1)T] Time t _g and red light time t _r :

{t t}_{g g} = = \frac{36003600 \times \times n no}{γ γ ((k k))}

{t t}_{r r} = = \frac{{C C}_{i i} - - γ γ ((k k))}{γ γ ((k k))} \times \times {t t}_{g g} = = \frac{[[{C C}_{i i} - - γ γ ((k k))]] 36003600 \times \times n no}{γ γ {((k k))}^{22}}

n is the number of vehicles allowed to enter the main line of the viaduct in this period, and n=[ρ _imax -ρ _i (k)]×Δ _i .

2. A kind of traffic control method that guarantees viaduct unimpeded as claimed in claim 1, is characterized in that: in described step (3), increase the yellow light time during the alternation of two phases in the whole signal cycle.

3. A kind of traffic control method that guarantees viaduct unimpeded as claimed in claim 1 or 2, is characterized in that: described traffic control method also comprises the following steps:

(4) Coordinated control of exit ramps adjacent to ground intersections:

Set the judgment criterion q _i (k)-ρ _i (k)×Δ _i -s _i (k-1)≥p _imax (k) for exit ramp overflow, if satisfied, trigger coordinated control and increase the number of adjacent ground intersections If it is not satisfied, the greenness ratio of the adjacent ground intersection will be restored to the original state.