CN110570049B - A low-level control method for synergistic optimization of highway mixed traffic flow convergence - Google Patents
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Abstract
Description
技术领域technical field
本发明涉及一种高速公路混合交通流汇流协同优化底层控制方法,属于交通工程领域。The invention relates to a bottom layer control method for synergistic optimization of mixed traffic flow confluence of expressways, and belongs to the field of traffic engineering.
背景技术Background technique
高速公路入口匝道作为整个高速公路系统的一个交通需求输入环节,也是拥堵容易产生的一个环节,对于整个高速公路系统的流畅平稳运行有十分重要的意义。随着智能网联汽车的出现与发展,未来的高速公路将会面临智能网联汽车与传统人类驾驶车辆混行的交通状况。智能网联汽车与传统人类驾驶车辆混合交通流环境下的决策控制是未来交通出行中需要长期面临的现实问题。因此,研究混合交通流环境下高速公路匝道汇流优化控制具有重要意义。As a traffic demand input link of the entire highway system, the highway on-ramp is also a link that is prone to congestion, and is of great significance to the smooth and stable operation of the entire highway system. With the emergence and development of intelligent networked vehicles, future highways will face a traffic situation where intelligent networked vehicles and traditional human-driven vehicles are mixed together. Decision control in the mixed traffic flow environment of intelligent networked vehicles and traditional human-driven vehicles is a long-term realistic problem that needs to be faced in future traffic travel. Therefore, it is of great significance to study the optimal control of expressway ramp convergence under mixed traffic flow environment.
对于高速公路匝道协同汇流优化控制问题,已有一些模型方法被提出,但现阶段所研究的决策控制方法多为假设自动驾驶车辆渗透率为100%的交通环境设计的决策方法,且仅都是在特定场景下讨论,未能全面地描述自动驾驶车辆与人类驾驶车辆组合排序场景且给出对应的轨迹优化方案。For the optimal control problem of synergistic convergence of expressway ramps, some model methods have been proposed, but most of the decision-making control methods studied at this stage are decision-making methods for the design of the traffic environment assuming that the penetration rate of autonomous vehicles is 100%, and only all of them are Discussed in specific scenarios, it fails to comprehensively describe the combination and sorting scenarios of autonomous vehicles and human-driven vehicles and give the corresponding trajectory optimization scheme.
发明内容SUMMARY OF THE INVENTION
将车辆轨迹优化控制问题定义为底层问题。该底层问题的求解需要根据场景以及优化目标来考虑具体的约束条件,包括道路几何约束、安全约束、车辆类型约束。本发明为解决在人类驾驶车辆(即传统驾驶车辆)和自动驾驶车辆(即智能网联车辆)混行交通状态下高速公路匝道车流汇入主干道时存在的该底层问题,提出一种高速公路混合交通流汇流协同优化底层控制方法。人类驾驶车辆为不可优化控制的车辆,自动驾驶车辆为可优化控制的车辆。The vehicle trajectory optimization control problem is defined as a low-level problem. The solution of the underlying problem needs to consider specific constraints according to the scene and optimization objectives, including road geometry constraints, safety constraints, and vehicle type constraints. In order to solve the underlying problem when the traffic flow of the expressway ramp merges into the main road in the mixed traffic state of human-driven vehicles (that is, traditional driving vehicles) and automatic-driving vehicles (that is, intelligent networked vehicles), the present invention proposes an expressway Synergistic optimization of the underlying control method for the convergence of mixed traffic flows. A human-driven vehicle is a vehicle that cannot be optimally controlled, and an autonomous vehicle is a vehicle that can be optimally controlled.
本发明为实现上述发明目的所采取的技术方案如下:The technical scheme adopted by the present invention for realizing the above-mentioned purpose of the invention is as follows:
一种高速公路混合交通流汇流协同优化底层控制方法,包括步骤:A low-level control method for synergistic optimization of highway mixed traffic flow convergence, comprising the steps of:
S1、确定微观跟驰模型,用所述微观跟驰模型描述车辆的跟驰状态,所述车辆的跟驰状态包括车辆的速度、加速度和位置;S1. Determine a microscopic car-following model, and use the microscopic car-following model to describe the car-following state of the vehicle, and the car-following state of the vehicle includes the speed, acceleration and position of the vehicle;
S2、获取混合交通流中车辆在通过汇流区域前的上游监测点的时刻和速度,并用所述微观跟驰模型预测车辆在上游监测点与汇流终点之间的车辆初始轨迹;所述上游监测点与汇流起点之间有一定距离的路段;所述汇流起点位于所述上游监测点和所述汇流终点之间;所述汇流起点和所述汇流终点之间的路段构成所述汇流区域;S2. Acquire the time and speed of the upstream monitoring point of the vehicle before passing through the confluence area in the mixed traffic flow, and use the microscopic car-following model to predict the initial vehicle trajectory of the vehicle between the upstream monitoring point and the end point of the confluence; the upstream monitoring point A road section with a certain distance from the starting point of the confluence; the starting point of the confluence is located between the upstream monitoring point and the end point of the confluence; the road section between the starting point of the confluence and the end point of the confluence constitutes the confluence area;
S3、基于所述微观跟驰模型,加入加速度约束、距离约束与安全约束,建立汇流模型;S3, based on the microscopic car-following model, adding acceleration constraints, distance constraints and safety constraints to establish a confluence model;
S4、针对混合交通流场景下的汇流过程中可能出现的各种无法顺利完成汇流的情况,拟制协同控制策略集;S4. According to various situations that may occur in the convergence process in the mixed traffic flow scenario, the convergence cannot be successfully completed, formulate a collaborative control strategy set;
S5、基于所述车辆初始轨迹,由所述汇流模型判断车辆是否可以顺利完成汇流;若判断结果为车辆可以顺利完成汇流,则车辆继续遵从所述微观跟驰模型的速度行驶;若判断结果为车辆无法顺利完成汇流,则需进一步判断车辆在汇流过程中出现的具体情况,并依据所述车辆在汇流过程中出现的具体情况对车辆做出所述步骤S4拟制的协同策略集中对应的协同控制策略,进而执行步骤S6;S5. Based on the initial trajectory of the vehicle, it is judged by the confluence model whether the vehicle can successfully complete the confluence; if the judgment result is that the vehicle can successfully complete the confluence, the vehicle continues to run at the speed of the microscopic car-following model; if the judgment result is If the vehicle cannot successfully complete the confluence, it is necessary to further judge the specific situation of the vehicle during the confluence process, and according to the specific situation of the vehicle during the confluence process, make a centralized coordination corresponding to the coordination strategy prepared in step S4 for the vehicle. Control strategy, and then execute step S6;
S6、将参与汇流过程的可优化控制的车辆确定为目标车辆,由步骤S5所做出的协同控制策略对所述目标车辆的行驶轨迹进行优化,并将该优化问题归结为离散时间状态约束的最优控制问题,用动态规划的思想求解得到关于所述目标车辆的协同优化控制策略,并将关于所述目标车辆的协同优化控制策略作用于所述目标车辆,控制所述目标车辆的运行。S6. Determine the optimally controllable vehicle participating in the confluence process as the target vehicle, optimize the driving trajectory of the target vehicle by the collaborative control strategy made in step S5, and attribute the optimization problem to a discrete-time state-constrained The optimal control problem is solved by using the idea of dynamic programming to obtain a cooperative optimal control strategy for the target vehicle, and the cooperative optimal control strategy for the target vehicle is applied to the target vehicle to control the operation of the target vehicle.
进一步地,所述步骤S4具体包括:Further, the step S4 specifically includes:
假定匝道和主干道均为单向单行车道,匝道上的车辆k将汇入主干道的连续车流的两车辆之间的间隔,所述主干道的连续车流的两车辆分别用车辆和车辆表示,其中车辆表示前车,车辆表示后车;Assuming that both the ramp and the main road are one-way one-way lanes, the vehicle k on the ramp will merge into the interval between the two vehicles of the continuous traffic flow of the main road, and the two vehicles of the continuous traffic flow of the main road use the vehicle and vehicles means that the vehicle Indicates the preceding vehicle, the vehicle Indicates the rear car;
针对混合交通流场景下的汇流过程中可能出现的各种情况,基于所述微观跟驰模型将车辆车辆k、车辆之间的关系分为可以顺利完成汇流与无法顺利完成汇流;所述无法顺利完成汇流又分为四种情况,第一种情况记为R1,表示车辆k与车辆之间距离太近,不满足可顺利完成汇流的约束条件;第二种情况记为R2,表示车辆k与车辆之间距离太近,不满足可顺利完成汇流的约束条件;第三种情况记为R3,表示车辆k与车辆且与车辆之间满足基本间隔要求但汇流过程不舒适;第四种情况记为R4,表示车辆k与车辆且与车辆之间的距离均太近,不满足可顺利汇流的约束条件;In view of various situations that may occur in the convergence process in the mixed traffic flow scenario, the vehicle vehicle k, vehicle The relationship between the two can be divided into those that can successfully complete the confluence and those that cannot successfully complete the confluence; the inability to successfully complete the confluence is further divided into four cases, the first case is recorded as R1, indicating that the vehicle k and the vehicle The distance between them is too close to meet the constraints that the confluence can be successfully completed; the second case is recorded as R2, indicating that the vehicle k and the vehicle The distance between them is too close to meet the constraints that the confluence can be successfully completed; the third case is recorded as R3, indicating that the vehicle k and the vehicle and with the vehicle The basic interval requirements are met, but the confluence process is uncomfortable; the fourth case is recorded as R4, indicating that the vehicle k and the vehicle and with the vehicle The distances between them are too close to meet the constraints of smooth confluence;
针对无法顺利完成汇流的四种情况,需要对当中的可优化控制的车辆进行协同控制;用H表示人类驾驶车辆,为不可优化控制的车辆;用A表示自动驾驶车辆,为可优化控制的车辆;用N表示无前车参与或无后车参与汇流;并规定车辆的组合顺序依次为车辆车辆k、车辆(例如:用HAN表示车辆为人类驾驶车辆、车辆k为自动驾驶车辆、车辆为无后车参与汇流。)For the four situations where the confluence cannot be successfully completed, it is necessary to coordinately control the vehicles that can be optimally controlled; use H to represent a human-driven vehicle, which is a vehicle that cannot be optimally controlled; use A to represent an autonomous vehicle, which can be optimally controlled. ;Use N to indicate that no preceding vehicle participates or no rear vehicle participates in the confluence; vehicle k, vehicle (Example: use HAN for vehicles driving vehicles for humans, vehicle k for autonomous vehicles, vehicles Participate in the confluence for no vehicles behind. )
基于不同的车辆组合、不同的车型组合,以及所述无法顺利完成汇流的四种情况,拟制协同控制策略集,如下表所示:Based on different vehicle combinations, different vehicle types, and the four situations in which the convergence cannot be successfully completed, a collaborative control strategy set is drawn up, as shown in the following table:
上表中,所述无优化是指车辆在对应的无法顺利完成汇流的情况下没有相应的控制策略,此时,匝道上的车辆k将以匝道尽头作为一个停止的虚拟前车,遵循所述微观跟驰模型持续减速甚至停车等待,直到主干道上出现满足可汇流的车辆间隔,车辆k才汇入主干道;In the above table, the non-optimization means that the vehicle does not have a corresponding control strategy when the corresponding confluence cannot be successfully completed. The microscopic car-following model continuously decelerates or even stops and waits, and vehicle k does not merge into the main road until there is a vehicle interval that satisfies the merging on the main road;
所述控制车辆k加速,是使t时刻车辆k的决策变量uk(t)满足:The acceleration of the control vehicle k is to make the decision variable u k (t) of the vehicle k at time t satisfy:
且vk(t)+uk(t)τ≤ve;and v k (t)+u k (t) τ≤ve ;
所述控制车辆k减速,是使t时刻车辆k的决策变量uk(t)满足:The control of vehicle k to decelerate is to make the decision variable u k (t) of vehicle k at time t satisfy:
且vk(t)+uk(t)τ≥0;and v k (t)+u k (t)τ≥0;
所述车辆k控制状态未知是对车辆k的控制方式可能是控制车辆k减速,也可能是控制车辆k加速,还可能是不控制车辆k,此时t时刻车辆k的决策变量uk(t)满足:The unknown control state of the vehicle k means that the control method for the vehicle k may be to control the vehicle k to decelerate, it may also be to control the vehicle k to accelerate, or it may not control the vehicle k. At this time, the decision variable u k (t )Satisfy:
vk(t)+uk(t)τ≤ve,v k (t)+u k (t) τ≤ve ,
且vk(t)+uk(t)τ≥0;and v k (t)+u k (t)τ≥0;
所述不控制车辆k,是使t时刻车辆k的决策变量uk(t)满足:The non-controlling vehicle k is to make the decision variable u k (t) of the vehicle k at time t satisfy:
即uk(t)=0; That is, u k (t) = 0;
所述控制车辆加速,是使t时刻车辆的决策变量满足:the control vehicle Acceleration is to make the vehicle at time t decision variables Satisfy:
且 and
所述不控制车辆是使t时刻车辆的决策变量满足:the uncontrolled vehicle is the vehicle at time t decision variables Satisfy:
即 which is
所述控制车辆减速,是使t时刻车辆的决策变量满足:the control vehicle Deceleration is to make the vehicle at time t decision variables Satisfy:
且 and
所述不控制车辆是使t时刻车辆的决策变量满足:the uncontrolled vehicle is the vehicle at time t decision variables Satisfy:
即 which is
其中,uk(t)作为t时刻车辆k的决策变量,表示在t时刻车辆k的加速度;vk(t)是车辆k在t时刻的速度;是根据所述微观跟驰模型所预测的车辆k在t+τ时刻的安全跟驰速度(其中Lk(t)表示在t时刻车辆k与其跟驰前车之间的相对距离,vk(t)表示车辆k在t时刻的速度,表示车辆k的跟驰前车在t时刻的速度);作为t时刻车辆的决策变量,表示在t时刻车辆的加速度;是车辆在t时刻的速度;是根据所述微观跟驰模型所预测的车辆在t+τ时刻的安全跟驰速度(其中表示在t时刻车辆与其跟驰前车之间的相对距离,表示车辆在t时刻的速度,表示车辆的跟驰前车在t时刻的速度);作为t时刻车辆的决策变量,表示在t时刻车辆的加速度;是车辆在t时刻的速度;是根据所述微观跟驰模型所预测的车辆在t+τ时刻的安全跟驰速度(其中表示在t时刻车辆与其跟驰前车之间的相对距离,表示车辆在t时刻的速度,表示车辆的跟驰前车在t时刻的速度);τ是车辆驾驶的反应时间;ve是期望速度。Among them, u k (t), as the decision variable of vehicle k at time t, represents the acceleration of vehicle k at time t; v k (t) is the speed of vehicle k at time t; is the safe car-following speed of vehicle k at time t+τ predicted according to the microscopic car-following model (wherein L k (t) represents the relative distance between vehicle k and the car in front of it at time t, v k ( t) represents the speed of vehicle k at time t, represents the speed of the vehicle in front of vehicle k at time t); as the vehicle at time t is the decision variable, representing the vehicle at time t acceleration; is a vehicle velocity at time t; is the vehicle predicted by the micro-following model Safe following speed at time t+τ (where represents the vehicle at time t The relative distance between it and the car in front of it, Indicates the vehicle The velocity at time t, Indicates the vehicle the speed of the following car at time t); as the vehicle at time t is the decision variable, representing the vehicle at time t acceleration; is a vehicle velocity at time t; is the vehicle predicted by the micro-following model Safe following speed at time t+τ (where represents the vehicle at time t The relative distance between it and the car in front of it, Indicates the vehicle The velocity at time t, Indicates the vehicle is the speed of the following vehicle at time t); τ is the driving reaction time of the vehicle; ve is the expected speed.
进一步地,所述步骤S6具体包括:Further, the step S6 specifically includes:
S6-1、基于所述微观跟驰模型预测目标车辆进入控制区域的时刻为t0,离开控制区域的时刻为tf;并将t0到tf的时间按离散时间间隔τ′平均分为N段,即N=(tf-t0)/τ′,定义控制决策时刻为t0+τ′,t0+2τ′,t0+3τ′,t0+4τ′,…,t0+(N-1)τ′,tf;所述控制区域为控制起点和所述汇流终点之间的路段;所述控制起点位于所述上游监测点和所述汇流起点之间;S6-1. Based on the microscopic car-following model, it is predicted that the time when the target vehicle enters the control area is t 0 , and the time when it leaves the control area is t f ; and the time from t 0 to t f is divided into discrete time intervals τ′ equally divided into N segments, namely N=(t f -t 0 )/τ′, define the control decision time as t 0 +τ′,t 0 +2τ′,t 0 +3τ′,t 0 +4τ′,…,t 0 +(N-1)τ′,t f ; the control area is the road section between the control starting point and the convergence end point; the control starting point is located between the upstream monitoring point and the convergence starting point;
S6-2、根据目标车辆在t0时刻的状态,计算目标车辆在t0+τ′时刻的容许状态集,以及目标车辆从t0时刻的状态到t0+τ′时刻的容许状态集中各个容许状态的转移成本;所述目标车辆在t0时刻的状态包括目标车辆在t0时刻的速度和位置;S6-2. According to the state of the target vehicle at time t 0 , calculate the allowable state set of the target vehicle at time t 0 +τ', and the allowable state set of the target vehicle from the state at time t 0 to time t 0 +τ'. The transition cost of the allowable state; the state of the target vehicle at time t 0 includes the speed and position of the target vehicle at time t 0 ;
S6-3、根据目标车辆在t0+τ′时刻的容许状态集,计算目标车辆在t0+2τ′时刻的容许状态集,以及目标车辆从t0+τ′时刻的状态到t0+2τ′时刻的容许状态集中各个容许状态的转移成本和累计成本;S6-3. According to the allowable state set of the target vehicle at time t 0 +τ', calculate the allowable state set of the target vehicle at time t 0 +2τ', and the state of the target vehicle from time t 0 +τ' to t 0 + The transition cost and cumulative cost of each allowable state in the allowable state set at time 2τ′;
S6-4、根据步骤S6-3的方法依次计算目标车辆在t0+3τ′,t0+4τ′,…,t0+(N-1)τ′,tf时刻的容许状态集,并计算得到tf时刻的容许状态集中的各个容许状态的累计成本;S6-4, according to the method of step S6-3, sequentially calculate the allowable state set of the target vehicle at time t 0 +3τ', t 0 +4τ',..., t 0 +(N-1)τ', t f , and Calculate the cumulative cost of each allowable state in the allowable state set at time t f ;
S6-5、判断目标车辆在tf时刻的容许状态集中的各个容许状态是否满足可以顺利完成汇流的条件,并将满足条件的容许状态纳入最终容许状态集中;S6-5, judging whether each allowable state in the allowable state set of the target vehicle at time tf satisfies the conditions for successfully completing the confluence, and incorporating the allowable states that meet the conditions into the final allowable state set;
S6-6、选择最终容许状态集中累计成本最小的容许状态作为tf时刻的最优状态;S6-6, select the allowable state with the smallest cumulative cost in the final allowable state set as the optimal state at time t f ;
S6-7、根据tf时刻的最优状态逆推得到t0+τ′,t0+2τ′,t0+3τ′,t0+4τ′,…,t0+(N-1)τ′,tf各时刻的最优状态,并将每个最优状态对应的控制决策纳入协同优化控制策略;S6-7. According to the optimal state at time t f , t 0 +τ′,t 0 +2τ′,t 0 +3τ′,t 0 +4τ′,…,t 0 +(N-1)τ are obtained by inverse inference ′, t f the optimal state at each moment, and incorporate the control decision corresponding to each optimal state into the collaborative optimization control strategy;
S6-8、根据所述协同优化控制策略对目标车辆在所述控制区域间的运行进行控制。S6-8. Control the operation of the target vehicle between the control areas according to the cooperative optimization control strategy.
进一步地,构建微观交通流仿真环境,对比不同交通情景下优化前后的仿真结果。Furthermore, a microscopic traffic flow simulation environment is constructed to compare the simulation results before and after optimization under different traffic scenarios.
与现有技术相比,本发明方法的有益效果是:Compared with the prior art, the beneficial effects of the method of the present invention are:
本发明提供的一种高速公路混合交通流汇流协同优化底层控制方法是对混合交通流状态下的高度公路匝道汇流过程进行建模,并针对自动驾驶车辆与人类驾驶车辆的各种混合排列组合场景分别给出了相应的协同汇流轨迹优化策略,本方法可用于分析不同交通状态、不同自动驾驶车辆渗透率等对交通的影响。本方法以微观跟驰模型描述微观的车辆跟驰状态,考虑高速公路的交通特征、几何约束、安全约束,将协同汇流轨迹优化问题归结为离散时间状态约束最优控制问题,并提出一种基于动态规划的求解方法来有效地解决这一问题,通过此方法可以使车辆以较高的速度平稳运行,进而提高了高速公路匝道在汇流区域的车辆通行能力,同时提高了车辆的平均行驶时间和路段交通流的稳定性。The low-level control method for collaborative optimization of highway mixed traffic flow convergence provided by the present invention is to model the high-level highway ramp convergence process under the mixed traffic flow state, and aims at various mixed arrangement and combination scenarios of automatic driving vehicles and human driving vehicles. Corresponding co-convergence trajectory optimization strategies are given respectively. This method can be used to analyze the impact of different traffic states and different penetration rates of autonomous vehicles on traffic. This method describes the micro-vehicle following state with a micro-following model, considers the traffic characteristics, geometric constraints, and safety constraints of the expressway, and reduces the coordinated convergence trajectory optimization problem to a discrete-time state-constrained optimal control problem, and proposes a method based on The dynamic programming solution method can effectively solve this problem. Through this method, the vehicle can run smoothly at a higher speed, thereby improving the vehicle capacity of the expressway ramp in the confluence area, and at the same time improving the average travel time and Stability of road traffic flow.
通过大量仿真实验证明,在引入协同汇流轨迹优化控制策略时,可以有效减少汇流行为下的车辆冲突次数,并且能有效提高汇流效率:单个匝道通行能力提高8%~10%。Through a large number of simulation experiments, it is proved that the introduction of the cooperative confluence trajectory optimization control strategy can effectively reduce the number of vehicle conflicts under the confluence behavior, and can effectively improve the confluence efficiency: the capacity of a single ramp is increased by 8% to 10%.
下面通过具体实施方式及附图对本发明作进一步详细说明,但并不意味着对本发明保护范围的限制。The present invention will be further described in detail below through specific embodiments and accompanying drawings, but it is not intended to limit the protection scope of the present invention.
附图说明Description of drawings
图1是本发明实施例中高速公路匝道在混合交通流场景下的汇流示意图。FIG. 1 is a schematic diagram of the convergence of expressway ramps in a mixed traffic flow scenario in an embodiment of the present invention.
图2是本发明实施例中车辆无法顺利完成汇流的第一种情况(R1)的示意图。FIG. 2 is a schematic diagram of the first situation ( R1 ) in which the vehicle cannot successfully complete the confluence in the embodiment of the present invention.
图3是本发明实施例中车辆无法顺利完成汇流的第二种情况(R2)的示意图。FIG. 3 is a schematic diagram of the second situation (R2) in which the vehicle cannot successfully complete the confluence in the embodiment of the present invention.
图4是本发明实施例中车辆无法顺利完成汇流的第三种情况(R3)的示意图。FIG. 4 is a schematic diagram of a third situation ( R3 ) in which the vehicle cannot successfully complete the confluence in the embodiment of the present invention.
图5是本发明实施例中车辆无法顺利完成汇流的第四种情况(R4)的示意图。FIG. 5 is a schematic diagram of the fourth situation ( R4 ) in which the vehicle cannot successfully complete the confluence in the embodiment of the present invention.
图6是本发明实施例中参与汇流过程的车辆组合和车型组合为HHA的三辆车,在无法顺利完成汇流的第二种情况(R2)下,且在无协同优化控制情况下的汇流轨迹图。Fig. 6 shows the combination of vehicles participating in the merging process and the three vehicles whose vehicle type combination is HHA in the embodiment of the present invention, in the second case (R2) where the merging cannot be successfully completed, and the trajectories of the merging in the case of no collaborative optimization control picture.
图7是本发明实施例中参与汇流过程的车辆组合和车型组合为HHA的三辆车,在无法顺利完成汇流的第二种情况(R2)下,且在有协同优化控制情况下的汇流轨迹图。Fig. 7 shows the combination of vehicles participating in the merging process and the three vehicles whose vehicle type combination is HHA in the embodiment of the present invention, in the second case (R2) where the merging cannot be successfully completed, and the trajectories of the merging under the condition of collaborative optimization control picture.
图8是本发明实施例中参与汇流过程的车辆组合和车型组合为HAH的三辆车,在无法顺利完成汇流的第一种情况(R1)下,且在无协同优化控制情况下的汇流轨迹图。Fig. 8 shows the combination of vehicles participating in the merging process and the three vehicles whose vehicle type combination is HAH in the embodiment of the present invention, in the first case (R1) where the merging cannot be successfully completed, and the trajectories of the merging in the case of no collaborative optimal control picture.
图9是本发明实施例中参与汇流过程的车辆组合和车型组合为HAH的三辆车,在无法顺利完成汇流的第一种情况(R1)下,且在有协同优化控制情况下的汇流轨迹图。Fig. 9 shows the combination of vehicles participating in the merging process and three vehicles whose vehicle type combination is HAH in the embodiment of the present invention, in the first case (R1) where the merging cannot be successfully completed, and the trajectories of the merging under the condition of collaborative optimization control picture.
具体实施方式Detailed ways
下面结合附图,通过对实施例的描述,对本发明的具体实施方式作进一步的说明。The specific embodiments of the present invention will be further described below through the description of the embodiments with reference to the accompanying drawings.
一种高速公路混合交通流汇流协同优化底层控制方法,包括步骤:A low-level control method for synergistic optimization of highway mixed traffic flow convergence, comprising the steps of:
S1、确定微观跟驰模型,用所述微观跟驰模型描述车辆的跟驰状态,所述车辆的跟驰状态包括车辆的速度、加速度和位置;S1. Determine a microscopic car-following model, and use the microscopic car-following model to describe the car-following state of the vehicle, and the car-following state of the vehicle includes the speed, acceleration and position of the vehicle;
S2、获取混合交通流中车辆在通过汇流区域前的上游监测点的时刻和速度,并用所述微观跟驰模型预测车辆在上游监测点与汇流终点之间的车辆初始轨迹;所述上游监测点与汇流起点之间有一定距离的路段;所述汇流起点位于所述上游监测点和所述汇流终点之间;所述汇流起点和所述汇流终点之间的路段构成所述汇流区域;S2. Acquire the time and speed of the upstream monitoring point of the vehicle before passing through the confluence area in the mixed traffic flow, and use the microscopic car-following model to predict the initial vehicle trajectory of the vehicle between the upstream monitoring point and the end point of the confluence; the upstream monitoring point A road section with a certain distance from the starting point of the confluence; the starting point of the confluence is located between the upstream monitoring point and the end point of the confluence; the road section between the starting point of the confluence and the end point of the confluence constitutes the confluence area;
S3、基于所述微观跟驰模型,加入加速度约束、距离约束与安全约束,建立汇流模型;S3, based on the microscopic car-following model, adding acceleration constraints, distance constraints and safety constraints to establish a confluence model;
S4、针对混合交通流场景下的汇流过程中可能出现的各种无法顺利完成汇流的情况,拟制协同控制策略集;S4. According to various situations that may occur in the convergence process in the mixed traffic flow scenario, the convergence cannot be successfully completed, formulate a collaborative control strategy set;
S5、基于所述车辆初始轨迹,由所述汇流模型判断车辆是否可以顺利完成汇流;若判断结果为车辆可以顺利完成汇流,则车辆继续遵从所述微观跟驰模型的速度行驶;若判断结果为车辆无法顺利完成汇流,则需进一步判断车辆在汇流过程中出现的具体情况,并依据所述车辆在汇流过程中出现的具体情况对车辆做出所述步骤S4拟制的协同策略集中对应的协同控制策略,进而执行步骤S6;S5. Based on the initial trajectory of the vehicle, it is judged by the confluence model whether the vehicle can successfully complete the confluence; if the judgment result is that the vehicle can successfully complete the confluence, the vehicle continues to run at the speed of the microscopic car-following model; if the judgment result is If the vehicle cannot successfully complete the confluence, it is necessary to further judge the specific situation of the vehicle during the confluence process, and according to the specific situation of the vehicle during the confluence process, make a centralized coordination corresponding to the coordination strategy prepared in step S4 for the vehicle. Control strategy, and then execute step S6;
S6、将参与汇流过程的可优化控制的车辆确定为目标车辆,由步骤S5所做出的协同控制策略对所述目标车辆的行驶轨迹进行优化,并将该优化问题归结为离散时间状态约束的最优控制问题,用动态规划的思想求解得到关于所述目标车辆的协同优化控制策略,并将关于所述目标车辆的协同优化控制策略作用于所述目标车辆,控制所述目标车辆的运行。S6. Determine the optimally controllable vehicle participating in the confluence process as the target vehicle, optimize the driving trajectory of the target vehicle by the collaborative control strategy made in step S5, and attribute the optimization problem to a discrete-time state-constrained The optimal control problem is solved by using the idea of dynamic programming to obtain a cooperative optimal control strategy for the target vehicle, and the cooperative optimal control strategy for the target vehicle is applied to the target vehicle to control the operation of the target vehicle.
实施例Example
如图1所示,为高速公路匝道在混合交通流场景下的汇流示意图,其中主干道和匝道均为单向单行车道,主干道上有若干自动驾驶车辆A和人类驾驶车辆H无规则排列的车流,匝道上有若干自动驾驶车辆A和人类驾驶车辆H无规则排列的车流需要通过汇流区域汇入主干道上的车流之间。假定主干道和匝道上的自动驾驶车辆A和人类驾驶车辆H均遵循微观跟驰模型。As shown in Figure 1, it is a schematic diagram of the confluence of expressway ramps in a mixed traffic flow scenario, in which both the main road and the ramp are one-way one-way lanes, and there are several autonomous vehicles A and human-driven vehicles H on the main road in an irregular arrangement. Traffic flow, there are a number of autonomous vehicles A and human-driven vehicles H on the ramp. The random arrangement of traffic needs to be merged into the traffic flow on the main road through the convergence area. It is assumed that both the autonomous vehicle A and the human-driven vehicle H on the main road and ramp follow the micro-following model.
S1、确定微观跟驰模型,用微观跟驰模型描述车辆的跟驰状态,车辆的跟驰状态包括车辆的速度、加速度和位置。S1. Determine a microscopic car-following model, and use the microscopic car-following model to describe the car-following state of the vehicle. The car-following state of the vehicle includes the speed, acceleration and position of the vehicle.
其中,微观跟驰模型如下:Among them, the micro car following model is as follows:
v(t+τ)=vmic(L(t),v(t),vlead(t)), (1)v(t+τ)=v mic (L(t), v(t), v lead (t)), (1)
u(t)=(v(t+τ)-v(t))/τ, (2)u(t)=(v(t+τ)-v(t))/τ, (2)
x(t+τ)=x(t)-v(t)τ-0.5u(t)τ2, (3)x(t+τ)=x(t)-v(t)τ-0.5u(t)τ 2 , (3)
方程(1)为一般化的车辆跟驰模型,描述车辆在t+τ时刻的速度,其中,L(t)为t时刻车辆与其跟驰前车的车间距;v(t)为t时刻车辆的速度,vlead(t)为t时刻车辆所跟驰的前车的速度。u(t)表示t时刻车辆的加速度。车辆在t时刻的位置用x(t)表示,在t+τ时刻的位置用x(t+τ)表示。Equation (1) is a generalized vehicle following model, which describes the speed of the vehicle at time t+τ, where L(t) is the distance between the vehicle and the preceding vehicle at time t; v(t) is the vehicle at time t The speed of , v lead (t) is the speed of the preceding vehicle followed by the vehicle at time t. u(t) represents the acceleration of the vehicle at time t. The position of the vehicle at time t is denoted by x(t), and the position at time t+τ is denoted by x(t+τ).
S2、获取混合交通流中车辆在通过汇流区域前的上游监测点的时刻和速度,并用微观跟驰模型预测车辆在上游监测点与汇流终点之间的车辆初始轨迹;上游监测点与汇流起点之间有一定距离的路段;汇流起点位于上游监测点和汇流终点之间;汇流起点和汇流终点之间的路段构成汇流区域。S2. Obtain the time and speed of the vehicle in the mixed traffic flow at the upstream monitoring point before passing through the confluence area, and use the micro-car following model to predict the initial trajectory of the vehicle between the upstream monitoring point and the end point of the confluence; the difference between the upstream monitoring point and the starting point of the confluence The starting point of the confluence is located between the upstream monitoring point and the end point of the confluence; the road segment between the starting point and the end point of the confluence constitutes the confluence area.
S3、基于微观跟驰模型,加入加速度约束、距离约束与安全约束,建立汇流模型。S3. Based on the microscopic car-following model, acceleration constraints, distance constraints and safety constraints are added to establish a confluence model.
其中,汇流模型如下:Among them, the confluence model is as follows:
假设匝道上的车辆k处于汇流区域,它将汇入主干道的连续车流的两车辆和之间,其中车辆为前车,车辆为后车。Assuming that vehicle k on the ramp is in the merge area, it will merge into the two vehicles of the continuous traffic flow of the main road and between which vehicles for the preceding vehicle, the vehicle for the rear car.
方程(4)用来表示汇流效用,反映汇流时的舒适度,是以汇流时的车间距以及汇流时匝道上的汇流车辆k和主干道后车的加速度来标定。其中,表示的是汇流行为在不受约束条件限制时的汇流效用。la为车辆车身长,为自动驾驶车辆与前车的最小安全车头距离,为人类驾驶车辆与前车的最小安全车头距离。汇流时,汇流车辆k实际跟驰主干道前车运行,而主干道后车实际跟驰汇流车辆k运行,它们的加速度都可以根据车辆跟驰模型计算得到。表示车辆k的加速度的绝对值;表示主干道后车的加速度的绝对值;bsafe表示最大允许减速度。ΦA为自动驾驶车辆集合,ΦH为人类驾驶车辆集合。η1和η2分别表示安全系数与礼貌系数,安全系数η1为常数,礼貌系数η2采用分段连续形式,如方程(5)所示,Vth是给定的速度阈值,ve为期望速度,β1和β2为常数。方程(6)中lk(t+τ)表示汇流决策,值为0则表示车辆k在t+τ时刻无法顺利完成汇流,值为1则表示车辆k在t+τ时刻可以顺利完成汇流。Equation (4) is used to express the confluence utility, which reflects the comfort level at the time of confluence. to calibrate the acceleration. in, Represents the sinking utility of sinking behavior when it is not restricted by constraints. l a is the length of the vehicle body, is the minimum safe frontal distance between the autonomous vehicle and the preceding vehicle, The minimum safe frontal distance between a human-driven vehicle and the vehicle in front. When merging, the merging vehicle k actually follows the preceding vehicle on the main road run while the main road behind the car The actual car-following and convergent vehicles k run, and their accelerations can be calculated according to the car-following model. represents the absolute value of the acceleration of vehicle k; Indicates the car behind the main road The absolute value of the acceleration; b safe represents the maximum allowable deceleration. Φ A is the set of autonomous vehicles, and Φ H is the set of human-driven vehicles. η 1 and η 2 represent the safety factor and the politeness factor, respectively, the safety factor η 1 is a constant, and the politeness factor η 2 adopts a piecewise continuous form, as shown in equation (5), V th is the given speed threshold, and ve is The desired velocity, β 1 and β 2 are constants. In equation (6), l k (t+τ) represents the convergence decision. A value of 0 means that vehicle k cannot successfully complete the convergence at time t+τ, and a value of 1 means that vehicle k can successfully complete the convergence at time t+τ.
S4、针对混合交通流场景下的汇流过程中可能出现的各种无法顺利完成汇流的情况,拟制协同控制策略集。具体如下:S4. In view of various situations that may occur in the convergence process in the mixed traffic flow scenario, the convergence cannot be successfully completed, formulate a collaborative control strategy set. details as follows:
假定匝道和主干道均为单向单行车道,匝道上的车辆k将汇入主干道的连续车流的两车辆之间的间隔,主干道的连续车流的两车辆分别用车辆和车辆表示,其中车辆表示前车,车辆表示后车。Assuming that both the ramp and the main road are one-way one-way lanes, the vehicle k on the ramp will merge into the interval between the two vehicles of the continuous traffic flow of the main road, and the two vehicles of the continuous traffic flow of the main road will use the vehicle and vehicles means that the vehicle Indicates the preceding vehicle, the vehicle Indicates the car behind.
针对混合交通流场景下的汇流过程中可能出现的各种情况,基于微观跟驰模型将车辆车辆k、车辆之间的关系分为可以顺利完成汇流与无法顺利完成汇流;无法顺利完成汇流分为四种情况:第一种情况记为R1,如图2所示,表示车辆k与车辆之间距离太近,不满足可顺利完成汇流的约束条件;第二种情况记为R2,如图3所示,表示车辆k与车辆之间距离太近,不满足可顺利完成汇流的约束条件;第三种情况记为R3,如图4所示,表示车辆k与车辆且与车辆之间满足基本间隔要求但汇流过程不舒适;第四种情况记为R4,如图5所示,表示车辆k与车辆且与车辆之间的距离均太近,不满足可顺利汇流的约束条件。Aiming at various situations that may occur in the convergence process in the mixed traffic flow scenario, the vehicle is divided into vehicle k, vehicle The relationship between the two can be divided into that the confluence can be successfully completed and the confluence cannot be successfully completed; the failure to complete the confluence is divided into four cases: the first case is recorded as R1, as shown in Figure 2, indicating that the vehicle k and the vehicle The distance between them is too close to meet the constraints that the confluence can be successfully completed; the second case is recorded as R2, as shown in Figure 3, indicating that the vehicle k and the vehicle The distance between them is too close to meet the constraints that the confluence can be successfully completed; the third case is recorded as R3, as shown in Figure 4, indicating that the vehicle k and the vehicle and with the vehicle The basic interval requirements are met, but the confluence process is uncomfortable; the fourth case is recorded as R4, as shown in Figure 5, indicating that the vehicle k and the vehicle and with the vehicle The distances between them are too close to meet the constraints of smooth confluence.
针对无法顺利完成汇流的四种情况,需要对当中的可优化控制的车辆进行协同控制;用H表示人类驾驶车辆,为不可优化控制的车辆;用A表示自动驾驶车辆,为可优化控制的车辆;用N表示无前车参与或无后车参与汇流;并规定车辆的组合顺序依次为车辆车辆k、车辆例如:用HAN表示车辆为人类驾驶车辆、车辆k为自动驾驶车辆、车辆为无后车参与汇流。For the four situations where the confluence cannot be successfully completed, it is necessary to coordinately control the vehicles that can be optimally controlled; use H to represent a human-driven vehicle, which is a vehicle that cannot be optimally controlled; use A to represent an autonomous vehicle, which can be optimally controlled. ;Use N to indicate that no preceding vehicle participates or no rear vehicle participates in the confluence; vehicle k, vehicle For example: use HAN for vehicles driving vehicles for humans, vehicle k for autonomous vehicles, vehicles Participate in the confluence for no vehicles behind.
基于不同的车辆组合、不同的车型组合,以及所述无法顺利完成汇流的四种情况,拟制协同控制策略集,如下表所示:Based on different vehicle combinations, different vehicle types, and the four situations in which the convergence cannot be successfully completed, a collaborative control strategy set is drawn up, as shown in the following table:
上表中,无优化是指车辆在对应的无法顺利完成汇流的情况下没有相应的控制策略,此时,匝道上的车辆k将以匝道尽头作为一个停止的虚拟前车,遵循微观跟驰模型持续减速甚至停车等待,直到主干道上出现满足可汇流的车辆间隔,车辆k才汇入主干道;In the above table, no optimization means that the vehicle does not have a corresponding control strategy when the corresponding confluence cannot be successfully completed. At this time, the vehicle k on the ramp will take the end of the ramp as a stopped virtual vehicle in front and follow the microscopic car following model. Continue to decelerate or even stop and wait until vehicle k merges into the main road until there is a vehicle interval on the main road that can meet the merging;
控制车辆k加速,是使t时刻车辆k的决策变量uk(t)满足:To control the acceleration of vehicle k is to make the decision variable u k (t) of vehicle k at time t satisfy:
且vk(t)+uk(t)τ≤ve; (7-1)And v k (t)+u k (t) τ≤ve ; (7-1)
控制车辆k减速,是使t时刻车辆k的决策变量uk(t)满足:Controlling vehicle k to decelerate is to make the decision variable u k (t) of vehicle k at time t satisfy:
且vk(t)+uk(t)τ≥0; (7-2)and v k (t)+u k (t)τ≥0; (7-2)
车辆k控制状态未知是对车辆k的控制方式可能是控制车辆k减速,也可能是控制车辆k加速,还可能是不控制车辆k,此时t时刻车辆k的决策变量uk(t)满足:The control state of vehicle k is unknown. The control method for vehicle k may be to control vehicle k to decelerate, or to control vehicle k to accelerate, or not to control vehicle k. At this time, the decision variable u k (t) of vehicle k at time t satisfies :
vk(t)+uk(t)τ≤ve,v k (t)+u k (t) τ≤ve ,
且vk(t)+uk(t)τ≥0; (7-3)and v k (t)+u k (t)τ≥0; (7-3)
不控制车辆k,是使t时刻车辆k的决策变量uk(t)满足:Not controlling the vehicle k is to make the decision variable u k (t) of the vehicle k at time t satisfy:
控制车辆加速,是使t时刻车辆的决策变量满足:control the vehicle Acceleration is to make the vehicle at time t decision variables Satisfy:
且 and
不控制车辆是使t时刻车辆的决策变量满足:do not control the vehicle is the vehicle at time t decision variables Satisfy:
控制车辆减速,是使t时刻车辆的决策变量满足:control the vehicle Deceleration is to make the vehicle at time t decision variables Satisfy:
且 and
不控制车辆是使t时刻车辆的决策变量满足:do not control the vehicle is the vehicle at time t decision variables Satisfy:
其中,uk(t)作为t时刻车辆k的决策变量,表示在t时刻车辆k的加速度;vk(t)是车辆k在t时刻的速度;是根据微观跟驰模型所预测的车辆k在t+τ时刻的安全跟驰速度;作为t时刻车辆的决策变量,表示在t时刻车辆的加速度;是车辆在t时刻的速度;是根据微观跟驰模型所预测的车辆在t+τ时刻的安全跟驰速度;作为t时刻车辆的决策变量,表示在t时刻车辆的加速度;是车辆在t时刻的速度;是根据微观跟驰模型所预测的车辆在t+τ时刻的安全跟驰速度;τ是车辆驾驶的反应时间;ve是期望速度。Among them, u k (t), as the decision variable of vehicle k at time t, represents the acceleration of vehicle k at time t; v k (t) is the speed of vehicle k at time t; is the safe car-following speed of vehicle k at time t+τ predicted by the micro-car-following model; as the vehicle at time t is the decision variable, representing the vehicle at time t acceleration; is a vehicle velocity at time t; is the vehicle predicted by the micro-following model Safe following speed at time t+τ; as the vehicle at time t is the decision variable, representing the vehicle at time t acceleration; is a vehicle velocity at time t; is the vehicle predicted by the micro-following model Safe following speed at time t+τ; τ is the reaction time of vehicle driving; ve is the desired speed.
S5、基于车辆初始轨迹,由汇流模型判断车辆是否可以顺利完成汇流;若判断结果为车辆可以顺利完成汇流,则车辆继续遵从微观跟驰模型的速度行驶;若判断结果为车辆无法顺利完成汇流,则需进一步判断车辆在汇流过程中出现的具体情况,并依据车辆在汇流过程中出现的具体情况对车辆做出步骤S4拟制的协同策略集中对应的协同控制策略,进而执行步骤S6。S5. Based on the initial trajectory of the vehicle, the confluence model judges whether the vehicle can successfully complete the confluence; if the judgment result is that the vehicle can successfully complete the confluence, the vehicle continues to follow the speed of the microscopic car following model; if the judgment result is that the vehicle cannot successfully complete the confluence, Then, it is necessary to further judge the specific situation of the vehicle during the merging process, and according to the specific situation of the vehicle during the merging process, make a coordinated control strategy corresponding to the coordinated strategy set prepared in step S4 for the vehicle, and then execute step S6.
S6、将参与汇流过程的可优化控制的车辆确定为目标车辆,由步骤S5所做出的协同控制策略对目标车辆的行驶轨迹进行优化,并将该优化问题归结为离散时间状态约束的最优控制问题,用动态规划的思想求解得到关于目标车辆的协同优化控制策略,并将关于目标车辆的协同优化控制策略作用于目标车辆,控制目标车辆的运行。具体如下:S6. Determine the optimally controllable vehicle participating in the confluence process as the target vehicle, optimize the driving trajectory of the target vehicle by the collaborative control strategy made in step S5, and reduce the optimization problem to the optimal discrete-time state constraint The control problem is solved by using the idea of dynamic programming to obtain the cooperative optimal control strategy of the target vehicle, and the cooperative optimal control strategy of the target vehicle is applied to the target vehicle to control the operation of the target vehicle. details as follows:
S6-1、基于微观跟驰模型预测目标车辆进入控制区域的时刻为t0,离开控制区域的时刻为tf;并将t0到tf的时间按离散时间间隔τ′平均分为N段,即N=(tf-t0)/τ′,定义控制决策时刻t为t0+τ′,t0+2τ′,t0+3τ′,t0+4τ′,…,t0+(N-1)τ′,tf;控制区域为控制起点和汇流终点之间的路段;控制起点位于上游监测点和汇流起点之间;S6-1. Based on the microscopic car-following model, it is predicted that the time when the target vehicle enters the control area is t 0 , and the time when it leaves the control area is t f ; and the time from t 0 to t f is divided into N segments equally according to the discrete time interval τ′ , namely N=(t f -t 0 )/τ′, the control decision time t is defined as t 0 +τ′,t 0 +2τ′,t 0 +3τ′,t 0 +4τ′,…,t 0 + (N-1)τ′,t f ; the control area is the road section between the control starting point and the confluence end point; the control starting point is located between the upstream monitoring point and the confluence starting point;
S6-2、根据目标车辆在t0时刻的状态,计算目标车辆在t0+τ′时刻的容许状态集,以及目标车辆从t0时刻的状态到t0+τ′时刻的容许状态集中各个容许状态的转移成本;目标车辆在t0时刻的状态包括目标车辆在t0时刻的速度和位置;S6-2. According to the state of the target vehicle at time t 0 , calculate the allowable state set of the target vehicle at time t 0 +τ', and the allowable state set of the target vehicle from the state at time t 0 to time t 0 +τ'. The transition cost of the allowable state; the state of the target vehicle at time t 0 includes the speed and position of the target vehicle at time t 0 ;
S6-3、根据目标车辆在t0+τ′时刻的容许状态集,计算目标车辆在t0+2τ′时刻的容许状态集,以及目标车辆从t0+τ′时刻的状态到t0+2τ′时刻的容许状态集中各个容许状态的转移成本和累计成本;S6-3. According to the allowable state set of the target vehicle at time t 0 +τ', calculate the allowable state set of the target vehicle at time t 0 +2τ', and the state of the target vehicle from time t 0 +τ' to t 0 + The transition cost and cumulative cost of each allowable state in the allowable state set at time 2τ′;
S6-4、根据步骤S6-3的方法依次计算目标车辆在t0+3τ′,t0+4τ′,…,t0+(N-1)τ′,tf时刻的容许状态集,并计算得到tf时刻的容许状态集中的各个容许状态的累计成本;S6-4, according to the method of step S6-3, sequentially calculate the allowable state set of the target vehicle at time t 0 +3τ', t 0 +4τ',..., t 0 +(N-1)τ', t f , and Calculate the cumulative cost of each allowable state in the allowable state set at time t f ;
S6-5、判断目标车辆在tf时刻的容许状态集中的各个容许状态是否满足可以顺利完成汇流的条件,并将满足条件的容许状态纳入最终容许状态集中;S6-5, judging whether each allowable state in the allowable state set of the target vehicle at time tf satisfies the conditions for successfully completing the confluence, and incorporating the allowable states that meet the conditions into the final allowable state set;
S6-6、选择最终容许状态集中累计成本最小的容许状态作为tf时刻的最优状态;S6-6, select the allowable state with the smallest cumulative cost in the final allowable state set as the optimal state at time t f ;
S6-7、根据tf时刻的最优状态逆推得到t0+τ′,t0+2τ′,t0+3τ′,t0+4τ′,…,t0+(N-1)τ′,tf各时刻的最优状态,并将每个最优状态对应的控制决策纳入协同优化控制策略;S6-7. According to the optimal state at time t f , t 0 +τ′,t 0 +2τ′,t 0 +3τ′,t 0 +4τ′,…,t 0 +(N-1)τ are obtained by inverse inference ′, t f the optimal state at each moment, and incorporate the control decision corresponding to each optimal state into the collaborative optimization control strategy;
S6-8、根据协同优化控制策略对目标车辆在控制区域间的运行进行控制。S6-8. Control the operation of the target vehicle between the control areas according to the collaborative optimization control strategy.
步骤S6用动态规划的思想求解得到关于目标车辆的协同优化控制策略,模型如下:Step S6 uses the idea of dynamic programming to obtain the collaborative optimization control strategy for the target vehicle. The model is as follows:
将目标车辆记为目标车辆i。目标函数方程(8)表示目标车辆i在控制区间内,行驶足够平缓且行驶速度接近期望速度,ve为期望速度。方程(9)表示目标车辆i的初始状态,即目标车辆i在t0时刻的状态。方程(10)与(11)表示目标车辆的过渡状态,方程(12)则是对汇流车辆k最终状态的汇流效用约束。K为车辆组合,表示匝道和主干道上直接参与汇流的车辆组合,且K∈{K1,K2,K3},车辆组合表示直接参与汇流的车辆有车辆k、车辆车辆车辆组合表示直接参与汇流的车辆有车辆k、车辆车辆组合表示直接参与汇流的车辆有车辆车辆k;而目标车辆i是车辆组合K中可优化控制的车辆。定义目标车辆i在每个阶段n的一组容许状态(即每个决策时刻的容许状态集),表示为Belman递推公式如方程(13)和方程(14)所示,用于求解子问题。方程(13)表示目标车辆i从初始状态(t0时刻的状态)到第1阶段(t0+τ时刻)的转移成本;第1阶段(t0+τ时刻)的容许状态是 为第1阶段(t0+τ时刻)的容许状态集。方程(14)中,是指每个子问题的目标值,即目标车辆i从初始状态(t0时刻的状态)到第n阶段(t0+nτ时刻)的累计成本;第n-1阶段(t0+(n-1)τ时刻)的容许状态是第n阶段(t0+nτ时刻)的容许状态是 为第n阶段(t0+nτ时刻)的容许状态集;是从第n-1阶段(t0+(n-1)τ时刻)的容许状态到第n阶段(t0+nτ时刻)的容许状态的转移成本,用方程(15)表示。Denote the target vehicle as target vehicle i. The objective function equation (8) indicates that the target vehicle i is in the control interval, travels smoothly enough and the travel speed is close to the desired speed, and ve is the desired speed. Equation (9) represents the initial state of the target vehicle i, that is, the state of the target vehicle i at time t 0 . Equations (10) and (11) represent the transition state of the target vehicle, and equation (12) is the merging utility constraint on the final state of the merging vehicle k. K is the vehicle combination, which represents the vehicle combination directly participating in the convergence on the ramp and the main road, and K∈{K 1 ,K 2 ,K 3 }, the vehicle combination Indicates that the vehicles directly participating in the confluence include vehicle k, vehicle vehicle vehicle combination Indicates that the vehicles directly participating in the confluence include vehicle k, vehicle vehicle combination Indicates that vehicles directly participating in the confluence have vehicles vehicle k; and the target vehicle i is the vehicle that can be optimally controlled in the vehicle combination K. Define a set of permissible states of the target vehicle i at each stage n (that is, the set of permissible states at each decision moment), expressed as The Belman recursion formulations are shown in Equation (13) and Equation (14) for solving the subproblems. Equation (13) represents the transition cost of the target vehicle i from the initial state (state at time t 0 ) to the first stage (time t 0 +τ ); the allowable state in the first stage (time t 0 +τ ) is is the allowable state set of the first stage (time t 0 +τ). In equation (14), refers to the target value of each sub-problem, that is, the cumulative cost of the target vehicle i from the initial state (state at time t 0 ) to the nth stage (time t 0 +nτ); the n-1th stage (t 0 +(n- 1) The allowable state at time τ) is The allowable state of the nth stage (time t 0 +nτ) is is the allowable state set of the nth stage (time t 0 +nτ); is the allowable state from the n-1th stage (time t 0 +(n-1)τ) Admissible state to the nth stage (time t 0 +nτ) The transfer cost of , expressed by equation (15).
本发明方法通过MATLAB编程建立微观交通流仿真环境(包括车辆跟驰与汇流),计算机编程实现高速公路混合交通流的仿真实验环境的参数及取值如下表所示:The method of the present invention establishes a microscopic traffic flow simulation environment (including vehicle following and merging) through MATLAB programming, and the parameters and values of the simulation experiment environment for realizing the mixed traffic flow of the expressway by computer programming are shown in the following table:
图6给出了参与汇流过程的车辆组合和车型组合为HHA的三辆车,在无法顺利完成汇流的第二种情况(R2)下,且在无协同优化控制情况下的汇流轨迹图,其中图(a)为位置-时间关系图,图(b)为速度-时间关系图,图(c)为加速度-时间关系图。Figure 6 shows the combination of vehicles participating in the convergence process and the three vehicles whose vehicle type combination is HHA. In the second case (R2) where the convergence cannot be successfully completed, and without collaborative optimal control, the convergence trajectory diagram, where Figure (a) is a position-time relationship diagram, Figure (b) is a velocity-time relationship diagram, and Figure (c) is an acceleration-time relationship diagram.
图7给出了参与汇流过程的车辆组合和车型组合为HHA的三辆车,在无法顺利完成汇流的第二种情况(R2)下,且在有协同优化控制情况下的汇流轨迹图,其中图(a)为位置-时间关系图,图(b)为速度-时间关系图,图(c)为加速度-时间关系图。Figure 7 shows the combination of vehicles participating in the convergence process and the three vehicles whose vehicle type combination is HHA. In the second case (R2) where the convergence cannot be successfully completed, and the convergence trajectory diagram under the condition of collaborative optimization control, where Figure (a) is a position-time relationship diagram, Figure (b) is a velocity-time relationship diagram, and Figure (c) is an acceleration-time relationship diagram.
对比优化前、后的汇流轨迹图,从速度-时间关系图(图6中(b)和图7中(b))以及加速度-时间关系图(图6中(c)和图7中(c))中可以看出,参与汇流的车辆在有协同优化控制情况下要比在无协同优化控制情况下的运行速度高且平稳,汇流车辆也能以较为平滑的速度尽早的完成汇流。Comparing the confluence trajectories before and after optimization, from the velocity-time relationship diagram (Fig. 6(b) and Fig. 7(b)) and the acceleration-time relationship diagram (Fig. 6(c) and Fig. 7(c) ))), it can be seen that the running speed of the vehicles participating in the merging is higher and smoother than that without the cooperative optimal control, and the merging vehicles can also complete the merging as soon as possible at a relatively smooth speed.
图8给出了参与汇流过程的车辆组合和车型组合为HAH的三辆车,在无法顺利完成汇流的第一种情况(R1)下,且在无协同优化控制情况下的汇流轨迹图,其中图(a)为位置-时间关系图,图(b)为速度-时间关系图,图(c)为加速度-时间关系图。Figure 8 shows the combination of vehicles participating in the convergence process and the three vehicles whose vehicle type combination is HAH. In the first case (R1) where the convergence cannot be successfully completed, and without collaborative optimal control, the convergence trajectory diagram, where Figure (a) is a position-time relationship diagram, Figure (b) is a velocity-time relationship diagram, and Figure (c) is an acceleration-time relationship diagram.
图9给出了参与汇流过程的车辆组合和车型组合为HAH的三辆车,在无法顺利完成汇流的第一种情况(R1)下,且在有协同优化控制情况下的汇流轨迹图,其中图(a)为位置-时间关系图,图(b)为速度-时间关系图,图(c)为加速度-时间关系图。Figure 9 shows the combination of vehicles participating in the convergence process and the three vehicles whose vehicle type combination is HAH. In the first case (R1) where the convergence cannot be successfully completed, and with the collaborative optimization control, the convergence trajectory diagram, where Figure (a) is a position-time relationship diagram, Figure (b) is a velocity-time relationship diagram, and Figure (c) is an acceleration-time relationship diagram.
对比优化前、后的汇流轨迹图,从速度-时间关系图(图8中(b)和图9中(b))以及加速度-时间关系图(图8中(c)和图9中(c))中可以看出,参与汇流的车辆在有协同优化控制情况下要比在无协同优化控制情况下的运行速度高且平稳,主干道后车受到汇流行为影响也较小。Comparing the confluence trajectories before and after optimization, from the velocity-time relationship diagram (Fig. 8(b) and Fig. 9(b)) and the acceleration-time relationship diagram (Fig. 8(c) and Fig. 9(c) ))), it can be seen that the running speed of the vehicles participating in the confluence is higher and smoother than that without the cooperative optimal control, and the vehicles behind the main road are less affected by the confluence behavior.
上述结合附图对本发明进行了示例性描述,显然本发明的具体实现并不受本文所示的实施例限制。The present invention has been exemplarily described above with reference to the accompanying drawings, and it is obvious that the specific implementation of the present invention is not limited by the embodiments shown herein.
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