CN108986488B - A method and device for determining a collaborative trajectory of a ramp-merge in a vehicle-to-vehicle communication environment - Google Patents

Abstract

The invention discloses a method and equipment for determining ramp merging cooperative track in a vehicle-vehicle communication environment, wherein the method comprises the steps of traversing main road vehicles one by one, judging whether ramp vehicles can smoothly merge into a certain main road vehicle and do not cause the influence exceeding an acceptance range on the operation of the main road vehicle, searching a proper lane changing gap and calculating the corresponding operation tracks of the ramp vehicles and the main road vehicle; if the appropriate lane changing gap is not searched, stopping the ramp vehicle for waiting; and if the suitable lane changing gap is searched, the ramp vehicles and the main road vehicles after the merging point run according to the calculated track, so that the ramp vehicles merge into the main road. Compared with the prior art, the method can enable the ramp vehicles to smoothly converge into the main road and enable the main road traffic flow to be influenced as little as possible by calculating the coordinated and matched motion track of the ramp automatic vehicles and the main road automatic vehicles, and achieves the local dynamic optimal effect.

Description

Method and equipment for determining ramp merging cooperative track in vehicle-vehicle communication environment

Technical Field

The invention belongs to the field of ramp afflux control in traffic signal control, and particularly relates to a method and equipment for determining a ramp afflux cooperative track in a vehicle-vehicle communication environment.

Background

With the great investment of the infrastructure of the traffic of various big cities, the enthusiasm of the construction of express ways is increased day by day. The expressway is used as a framework of an urban road system, bears main traffic flow of a city, can effectively relieve urban traffic jam, improves the running efficiency and the service level of an urban road network, and has the characteristics of smoothness, quickness, comfort and convenience. However, with the increasing and rapid increase of urban traffic, urban expressways lose their quick and efficient functions, and the processing is not good, but rather, the expressways become congestion nodes in urban traffic systems. How to adopt an effective control method to improve the use efficiency of an expressway system, strengthen the traffic control of the expressway system and recover the due functions of the expressway system becomes important for solving the traffic problems in cities.

If the geometric design of the expressway is reasonable, the acceleration lanes near the entrance ramp can generally ensure that vehicles driving into the acceleration lanes can safely merge into the main line traffic flow, but cannot ensure that the driving vehicles do not generate extrusion or retardation on the main line traffic flow in the process of merging into the main line. If some form of "merge control" can be taken, then "squeeze" or drag can be reduced, avoiding situations where the main line vehicle is forced to change lanes.

Under the traditional scene, the ramp vehicle judges the main road traffic flow through the driver, and searches for a proper gap to insert the main road traffic flow. However, the observation range, the calculation capability and the judgment accuracy of people are limited, and the situation that vehicles on a ramp cannot converge into a main road or forcibly converge into the main road to cause traffic jam of the main road often occurs.

With the development of artificial intelligence and car networking, car-car cooperative systems enter the field of vision of people. The vehicle-vehicle cooperation system is a system which acquires vehicle information based on technologies such as wireless communication, sensing detection and the like, performs information interaction and sharing, realizes intelligent cooperation and cooperation between vehicles, and achieves the aims of optimizing and utilizing system resources, improving road traffic safety and relieving traffic jam.

However, most of the existing researches provide safety early warning and lane change prompt for vehicles in a confluence area, the research on the cooperative control method of the automatic driving vehicles in the communication environment of the vehicles and the vehicles in the opposite directions is less, and even if the control method is provided, the accurate running tracks of vehicles merged into the ramp and main road traffic flow cannot be quantitatively provided.

Disclosure of Invention

The purpose of the invention is as follows: with the development of the automatic driving automobile and the car networking, the invention aims to provide a method and equipment for determining a ramp merging cooperative track in a car-to-car communication environment.

The technical scheme is as follows: in order to achieve the purpose, the invention adopts the following technical scheme:

a method for determining a ramp merging cooperative track in a vehicle-vehicle communication environment comprises the following steps:

(1) sequentially numbering vehicles on the upstream of the merging point of the ramp on the main road in the sequence from the downstream to the upstream, sequentially traversing from a second vehicle, and searching for a proper lane changing gap; the method for judging whether the insertion position exists between each vehicle and the front vehicle comprises the following steps:

(1.1) setting C_iAnd C_i-1One more V is arranged in the middle_iVirtual vehicle C traveling at speed_uCalculating C using IDM following model_iAcceleration a of_iAnd virtual vehicle C_uAcceleration a of_u(ii) a Wherein i is the serial number of the vehicles on the main road;

(1.2) if a_iAnd a_uIf the current vehicle is not smaller than the set threshold value, continuing to execute the step (1.3), otherwise, judging that the current vehicle does not have an insertion position, and judging the next vehicle;

(1.3) judging the ramp vehicle C₀Whether the speed can be changed in a coordinated manner with a rear vehicle at an insertion position or not is achieved, the purpose of smoothly merging into a main road is achieved, and the specific method is as follows:

straightening a ramp to be parallel to a main line, and establishing a planar two-dimensional coordinate system, wherein the horizontal axis is a time axis t, and the vertical axis is a distance axis y;

is provided with C₀Accelerated at constant acceleration to obtain C₀Is of₀(t) setting a virtual vehicle C_uIs always located at C_iAnd C_i-1In the middle of the center, a virtual vehicle C is obtained_uIs of_u(t)；

Calculating parabola y₀(t) and line y_u(t) whether the intersection point at the time of tangency satisfies three constraint conditions: acceleration limit of 0-a_mLane change position limit L₁≤y_u(t)≤L₂And main road vehicle deceleration degree limit d_minD is not less than 1; wherein a is_mFor maximum acceleration, [ L ]₁,L₂]Y-axis range for lane-changing position, d is main road vehicle speed reduction factor, d_minIs a set reduction coefficient threshold value;

if satisfied, it indicates C₀At C_iThe previous insertion does not cause obvious influence on the main road, the step (3) is carried out, otherwise, the current vehicle is considered to have no insertion position, and the judgment of the next vehicle is carried out;

(2) if the vehicle cannot search a proper insertion position after traversing is finished, C₀Stopping at the entrance of the ramp for waiting;

(3)C₀stably accelerating to dXV with acceleration a_i，C_iDecelerating to d × V_i，C₀Keeping vehicle speed dXV_iAnd smoothly merge into the main road.

Preferably, in the step (1.3), C is set to 0 in the two-dimensional coordinate system when t is the current time point₀The position point is y is equal to 0, and the ramp vehicle C₀Run of (2)

Virtual vehicle C_uRun of (2)

Wherein, b_mFor the main road vehicle C_iAllowable deceleration of, S_iFor the main road vehicle C_iThe distance between the car heads.

Preferably, in step (1.3), the intersection point is obtained by solving the following equation:

y_u(t)＝y₀(t)

the equation is developed and solved specifically

Converting the three constraints into constraints with t and delta t as variables, and searching whether a feasible solution exists in a plane rectangular coordinate system with delta t as a horizontal axis and t as a vertical axis.

Preferably, step (1.1) is C_iAnd C_uAcceleration a of_iAnd a_uThe calculation formula is as follows:

wherein v is₀Ideal driving speed, s₀For a stationary safety distance, T a safety time interval, a starting acceleration, b a comfort deceleration, δ>0 is an acceleration index, v_iIs the speed of the ith vehicle, S_iThe head distance of the ith vehicle.

The invention discloses computer equipment in another aspect, which comprises a memory, a processor and a computer program stored on the memory and capable of running on the processor, wherein the computer program realizes the ramp merging collaborative trajectory determination method when being loaded to the processor.

Has the advantages that: the ramp vehicle exceeds the constraints of the observation range, the calculation capability and the judgment accuracy of human drivers under the vehicle-vehicle communication condition. According to the convergence control strategy of the invention, the ramp vehicles and the main road traffic flow run according to the accurately calculated track, thereby reducing the occurrence of 'extrusion' or retardation, avoiding the situation that the main line vehicle is forced to change lanes, realizing that the main road traffic flow is interfered as low as possible while the ramp vehicles converge into the main road, and achieving the local dynamic optimal effect.

Drawings

Fig. 1 is a schematic diagram of ramp geometry, vehicle coordinates, and distance.

Fig. 2 is a schematic diagram of the coordinate movement of the virtual vehicle and the ramp merging vehicle.

Detailed Description

The invention is further described with reference to the following figures and specific embodiments.

The embodiment of the invention discloses a method for determining a ramp merging collaborative track in a vehicle-vehicle communication environment. The method comprises the steps of traversing main road vehicles one by one, judging whether ramp vehicles can smoothly converge into a certain main road vehicle and do not influence the operation of the main road vehicle by more than 10%, searching a proper lane change gap and calculating the corresponding running tracks of the ramp vehicles and the main road vehicle; if the appropriate lane changing gap is not searched, stopping the ramp vehicle for waiting; and if the suitable lane changing gap is searched, the ramp vehicles and the main road vehicles after the merging point run according to the calculated track, so that the ramp vehicles merge into the main road.

As shown in FIG. 1, let us assume that a fully-automatically driven vehicle (numbered C) is on the current ramp₀) Has a velocity of V₀The shortest distance from the allowable lane change zone is L₁The length of the permitted lane change zone is L₀The farthest distance from the allowable lane-changing area is L₂＝L₁+L₀(ii) a The fully-automatic driving vehicles on the main road at the upstream of the junction point of the ramp are sequentially numbered as C from downstream to upstream₁、C₂……C_n。C_nThe farthest vehicle within H meters from the ramp merging area (empirical value of H is 500), C₀And C₁、C₂……C_nAnd automatically establishing communication connection.

The method for determining the ramp merging collaborative track in the embodiment of the invention specifically comprises the following steps:

1) from C₂Start, traverse C₂、C₃……C_nAnd repeatedly executing the steps 11) to 19) to search for a proper lane change gap. Namely, traversing the vehicles in the main road fleet, searching for a proper inserted vehicle, and mainly executing two layers of judgment conditions: the first layer is used for judging whether the size of the gap is sufficient or not; and if the second layer meets the first layer, judging whether the ramp vehicle can change speed in a coordinated manner with the rear vehicle in the insertion position, thereby achieving the purpose of smoothly converging into the main road.

11) Marking the number of the currently traversed vehicle as C_i(i is more than or equal to 2 and less than or equal to n) which is connected with the front vehicle C_i-1Head interval of S_iAt a current vehicle speed V_iWith a minimum distance Y from the zone of permitted lane change_i；

12) The following scenario judgment is carried out:

121) if C_iAnd C_i-1Suddenly increase one more V in the middle_iVirtual vehicle C traveling at speed_uCalculating C_iAcceleration a of_iAnd virtual vehicle C_uAcceleration a of_u；

This step uses the IDM following model to calculate C_iAnd C_uAcceleration a of_iAnd a_u；

Wherein v is₀Ideal driving speed (default 35m/s), s₀A static safety distance (default 10m), T a safety time interval (default 2s), a breakaway acceleration (default 2 m/s)²) B is comfort deceleration (default 1 m/s)²)，δ>0 is the acceleration index (default 2), v_iIs the speed of the ith vehicle, S_iThe head distance of the ith vehicle.

122) If a_iAnd a_uAre not less than-1 m/s²If yes, the step 13) is continuously executed, otherwise, the loop is ended, the next loop is entered, and the vehicle C is traversed_i+1；

13) Let virtual vehicle C_uRetention and C_iRunning at the same speed, virtual vehicle C_uIs always located at C_iFront stage

At least one of (1) and (b);

14) straightening a ramp to be parallel to a main line, establishing a planar two-dimensional coordinate system, wherein the horizontal axis is a time axis t, the current time is t-0, and the vertical axis is a distance axis y, C₀The position point is y which is 0; the following coordinates were determined:

141) calculating y-axis range [ L ] of lane-changing position₁,L₂]；

142) Virtual vehicle C when t is calculated to be 0_uY coordinate of

15) Is provided with C₀The current vehicle speed is V₀At the mostA large acceleration of a_m，C₀Accelerated at constant acceleration to obtain C₀Run of (2)

0≤a≤a_m；

16) Vehicle C with main road_iCoordination C₀The maximum influence degree of the main road vehicle is 10 percent, and the speed is reduced to 0.9V at the minimum_i(ii) a The speed reduction coefficient is d, and d is more than or equal to 0.9 and less than or equal to 1. Main road vehicle C_iIs b_m(ii) a Calculating a virtual vehicle trajectory:

161) calculate from V_iDecelerating to d × V_iRequired time of

162) Calculating the time C of deceleration_iDistance of advance

163) If the virtual vehicle will always be at C_iFront stage

Get a virtual vehicle C_uRun of (2)

17) Solving the following equation:

y_u(t)＝y₀(t)

18) judging whether the solved solution meets three constraint conditions:

acceleration limit of 0-a_m；

Lane change position limit L₁≤y_u(t)≤L₂；

The deceleration degree of the vehicle on the main road is limited, and d is more than or equal to 0.9 and less than or equal to 1;

19) if the calculated t, a and d satisfy the constraint conditions, then C is indicated₀At C_iThe previous insertion does not cause obvious influence on the main path, and the loop is skipped to enter the step 3); otherwise, entering the next cycle;

2) if the vehicle is traversed and the proper inserting position cannot be searched, C₀Stopping at the entrance of the ramp for waiting;

3)C₀stably accelerating to dXV with acceleration a_i，C_iDecelerating to d × V_i，C₀Keeping vehicle speed dXV_iAnd smoothly merge into the main road.

When the second layer condition is determined, the essence is to calculate the parabola y₀And a straight line y_uWhether the intersection point at the time of tangency satisfies three constraint conditions: acceleration limit, lane change position limit, and main road vehicle deceleration degree limit.

y_u(t)＝y₀(t)

The equation is developed and solved specifically

Constrain three

0.9≤d≤1

0≤a≤a_m

L₁≤y_u(t)≤L₂

Is arranged into

That is, according to the relationship between t and Δ t, whether a feasible solution exists is found in a rectangular plane coordinate system with Δ t as the horizontal axis and t as the vertical axis.

If a feasible solution exists, illustrate C₀At C_iBefore insertion does not cause obvious influence on main path, end traversal, C₀And C_iProgress is planned until confluence, see fig. 2. Otherwise, entering the next judgment cycle.

Based on the same technical concept, the embodiment of the invention discloses a computer device, which comprises a memory, a processor and a computer program stored on the memory and capable of running on the processor, wherein the computer program is loaded to the processor to realize the ramp merging collaborative trajectory determination method described in the embodiment.

Claims (5)

Translated fromChinese

1.一种车车通信环境下匝道汇入协同轨迹确定方法，其特征在于，包括以下步骤：1. A method for determining a collaborative trajectory of ramp-in under a vehicle-to-vehicle communication environment, is characterized in that, comprises the following steps:(1)将主路上匝道汇入点上游的车辆以从下游到上游的顺序依次编号，从第二辆车开始依次遍历，搜索合适的换道间隙；其中判断每辆车与前车之间的是否存在插入位置的方法包括：(1) Number the vehicles upstream of the entry point of the ramp on the main road in order from downstream to upstream, traverse from the second vehicle in sequence, and search for a suitable lane-changing gap; in which, determine the distance between each vehicle and the preceding vehicle. The methods for the presence or absence of the caret position include:(1.1)设C_i与C_i-1正中间多出一辆以速度V_i行驶的虚拟车辆C_u，使用IDM跟驰模型计算C_i的加速度a_i与虚拟车辆C_u的加速度a_u；其中i为主路上车辆编号；(1.1) set a virtual vehicle C_u running at the speed V_i in the middle of C_i and C_i-1 , and use the IDM car following model to calculate the acceleration a_i of C_i and the acceleration a_{u of the virtual vehicle C u;} where i is the vehicle number on the main road;(1.2)若a_i与a_u均不小于设定的阈值，则继续执行步骤(1.3)，否则认为当前车辆不存在插入位置，进行下一辆车的判断；(1.2) If both a_i and a_u are not less than the set threshold, then continue to perform step (1.3), otherwise it is considered that the current vehicle does not have an insertion position, and the next vehicle is judged;(1.3)判断匝道车辆C₀是否能够通过与插入位置的后车进行协同变化速度的方式，达到顺利汇入主路的目的，具体方法为：(1.3) Determine whether the ramp vehicle C₀ can successfully merge into the main road by changing the speed in coordination with the rear vehicle at the insertion position. The specific method is as follows:将匝道拉直与主线平行，建立平面二维坐标系，横轴为时间轴t，纵轴为距离轴y；Straighten the ramp to be parallel to the main line, and establish a plane two-dimensional coordinate system, the horizontal axis is the time axis t, and the vertical axis is the distance axis y;设C₀以恒定加速度加速，得到C₀的运行轨迹y₀(t)，设虚拟车辆C_u一直位于C_i与C_i-1正中间，得到虚拟车辆C_u的运行轨迹y_u(t)；Assume that C₀ accelerates at a constant acceleration to obtain the running track y₀ (t) of C₀ , and set the virtual vehicle C_u to be in the middle of C_i and C_i-1 all the time, and obtain the running track y_u (t) of the virtual vehicle C_u ;计算抛物线y₀(t)与直线y_u(t)相切时的交点是否满足三个约束条件：加速度限制0≤a≤a_m、换道位置限制L₁≤y_u(t)≤L₂和主路车辆减速程度限制d_min≤d≤1；其中a_m为最大加速度，[L₁,L₂]为可换道位置的y轴范围，L₁为C₀距离准许变道区的最近距离，L₂为C₀距离准许变道区的最远距离，d为主路车辆速度折减系数,d_min为设定的折减系数阈值；Calculate whether the intersection point when the parabola y₀ (t) is tangent to the straight line y_u (t) satisfies three constraints: acceleration limit_0≤a≤am , lane change position limit L₁ ≤y_u (t)≤L₂ and the main road vehicle deceleration degree limit d_min ≤ d ≤ 1; where a_m is the maximum acceleration, [L₁ , L₂ ] is the y-axis range of the lane-changing position, and L₁ is the closest distance from C₀ to the permitted lane-changing area distance, L₂ is the farthest distance from C₀ to the permitted lane change area, d is the speed reduction coefficient of the main road vehicle, and d_min is the set reduction coefficient threshold;若满足则说明C₀在C_i之前插入不会给主路造成明显影响，进入步骤(3)，否则认为当前车辆不存在插入位置，进行下一辆车的判断；If it is satisfied, it means that the insertion of C₀ before C_i will not have a significant impact on the main road, and step (3) is entered, otherwise, it is considered that the current vehicle does not have an insertion position, and the judgment of the next vehicle is carried out;(2)若车辆遍历结束未能搜索到合适的插入位置，则C₀在匝道入口处停车等待；(2) If the vehicle fails to search for a suitable insertion position at the end of the traversal, then C₀ stops at the entrance of the ramp and waits;(3)C₀以加速度a稳定加速至d×V_i，C_i减速至d×V_i，C₀保持车速d×V_i并顺利汇入主路。(3) C₀ stably accelerates to d×V_i with acceleration a, C_i decelerates to d×V_i , C₀ maintains the vehicle speed d×V_i and smoothly merges into the main road.2.根据权利要求1所述的一种车车通信环境下匝道汇入协同轨迹确定方法，其特征在于，所述步骤(1.3)中，二维坐标系中以当前时刻为t＝0，C₀所在位置点为y＝0，匝道车辆C₀的运行轨迹

虚拟车辆C_u的运行轨迹

其中，b_m为主路车辆C_i的容许减速度，S_i为主路车辆C_i的车头间距，Y_i为主路车辆C_i距离准许变道区的最近距离。2 . The method for determining a collaborative trajectory of a ramp merged into a vehicle-to-vehicle communication environment according to claim 1 , wherein in the step (1.3), in the two-dimensional coordinate system, the current moment is t=0, C The location point of₀ is y=0, and the running track of the ramp vehicle C₀

The running track of the virtual vehicle C_u

Among them, b_m is the allowable deceleration of the main road vehicle C_i , S_i is the head distance of the main road vehicle C_i , and Y_i is the shortest distance from the main road vehicle C_i to the permitted lane change area.3.根据权利要求2所述的一种车车通信环境下匝道汇入协同轨迹确定方法，其特征在于，所述步骤(1.3)中通过求解如下方程得到交点：3. The method for determining a collaborative trajectory of a ramp into a vehicle under a vehicle-to-vehicle communication environment according to claim 2, wherein in the step (1.3), the intersection is obtained by solving the following equation:y_u(t)＝y₀(t)y_u (t)=y₀ (t)

将方程具体展开解得Expand the equation to get

将三个约束转换成以t与Δt为变量的约束，在以Δt为横轴，t为纵轴的平面直角坐标系中，寻找是否存在可行解。Convert the three constraints into constraints with t and Δt as variables, and find whether there is a feasible solution in a plane rectangular coordinate system with Δt as the horizontal axis and t as the vertical axis.4.根据权利要求1所述的一种车车通信环境下匝道汇入协同轨迹确定方法，其特征在于，步骤(1.1)中C_i和C_u的加速度a_i与a_u计算公式为：4. under a kind of vehicle-to-vehicle communication environment according to claim 1, it is characterized in that, in step (1.1), the acceleration a_i of C_i and C_u and the calculation formula of a_u are:

其中，v₀为理想驾驶速度，s₀为静止安全距离，T为安全时间间隔，a₀为起步加速度，b为舒适减速度，δ>0为加速度指数，v_i为第i辆车的速度，S_i为第i辆车的车头间距。Among them, v₀ is the ideal driving speed, s₀ is the static safety distance, T is the safety time interval, a₀ is the starting acceleration, b is the comfortable deceleration, δ>0 is the acceleration index, and vi is the speed of the_ith vehicle , S_i is the head-to-head distance of the i-th vehicle.5.一种计算机设备，包括存储器、处理器及存储在存储器上并可在处理器上运行的计算机程序，其特征在于，所述计算机程序被加载至处理器时实现根据权利要求1-4任一项所述的匝道汇入协同轨迹确定方法。5. A computer device comprising a memory, a processor and a computer program that is stored on the memory and can run on the processor, wherein the computer program is loaded into the processor to realize any one of claims 1-4. A method for determining a ramp-in-cooperative trajectory.

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