Vehicle dispatching method and system at intersection without signal lights

Abstract

This invention discloses a vehicle dispatching method and system for intersections without traffic lights. The method includes: acquiring vehicles waiting to cross at the intersection without traffic lights and dividing them into platoons; identifying the two platoons closest to the intersection and determining whether their trajectories overlap when crossing the intersection; if not, the two platoons will not collide, and the two platoons will pass through the intersection normally; if so, there is a possibility of collision, and the overlapping area is the potential collision area; calculating the arrival time of the two platoons at the potential collision area, and prioritizing the platoon that arrives first according to the principle of first-come, first-served, and controlling the other platoon to pass later; determining whether a collision will occur when the two platoons pass through the intersection at their current speed; if so, controlling the platoon to slow down; if not, controlling the platoon to accelerate. This invention can solve the problem of congestion and collisions at intersections with low traffic volume.

Description

Technical Field

[0001] The invention belongs to the field of traffic technology, and in particular relates to a vehicle dispatching method and system at an intersection without signal lights. Background Art

[0002] With the development of economy and technology, people's living standards are constantly improving. In the process of rapid urbanization, rural areas are shifting to central villages and small towns, and the urbanization process is accelerating. At the same time, road construction between towns is also developing continuously. However, due to the rapid urbanization, some intersections have not yet been equipped with traffic facilities such as traffic lights, which makes it easy for vehicles to have traffic accidents when passing through intersections. In addition, setting up traffic lights at intersections with less traffic volume not only requires a lot of costs, but also seriously affects the traffic efficiency of the intersection.

[0003] In recent years, 5G, Internet of Vehicles, big data, cloud computing, and road electronic technologies have developed rapidly, and vehicle-road collaboration technology has developed rapidly. This technology uses wireless communication and new generation Internet technologies to implement all-round dynamic real-time information interaction between vehicles and roads, and conducts active vehicle safety control and road collaboration management based on the collection and integration of dynamic traffic information in all time and space, fully realizing the effective collaboration of people, vehicles and roads, ensuring traffic safety, and improving traffic efficiency, thus forming a safe, efficient and environmentally friendly road traffic system. By using V2V communication between vehicles, multiple vehicles can make collaborative decisions, reasonably plan execution plans, ensure the safe passage of vehicles through intersections, and improve the traffic efficiency of intersections. Summary of the invention

[0004] The purpose of the present invention is to provide a vehicle dispatching method and system at an intersection without signal lights, so as to solve the traffic problem at the intersection with small vehicle flow.

[0005] The technical solution adopted by the present invention is as follows:

[0006] In a first aspect, the present invention provides a method for dispatching vehicles at a non-signalized intersection, comprising the following steps:

[0007] Obtain vehicles waiting to pass at intersections without traffic lights and divide them into fleets;

[0008] Determine the two convoys closest to the intersection, and determine whether there is an overlapping area in the running trajectories of the two convoys when passing through the intersection;

[0009] If not, the two convoys will not collide, and the two convoys are controlled to pass through the intersection normally;

[0010] If yes, there is a possibility of collision between the two convoys, and the overlapping area is the possible collision area; and the time when the two convoys arrive at the possible collision area is calculated, and the convoy that arrives at the possible collision area first is controlled to pass first according to the principle of first come first served, and the other convoy is controlled to pass later;

[0011] Then calculate the time when the priority team leaves the possible collision area, combined with the time when the rear team arrives at the possible collision area, to determine whether the two teams will collide when passing the intersection at the current speed; if so, control the rear team to slow down so that the time when the rear team arrives at the possible collision area is exactly the time when the priority team leaves the possible collision area; if not, control the rear team to accelerate so that the time when the rear team arrives at the possible collision area is exactly the time when the priority team leaves the possible collision area, or control the rear team to pass the intersection normally.

[0012] Optionally, the fleet division method is:

[0013] Identify the lead vehicle;

[0014] Determine a set of target vehicles that have the same driving direction as the leader vehicle and are within a certain distance from the leader vehicle; the same driving direction includes the same current driving lane and the same target driving direction; the target driving direction includes left turn, straight ahead and right turn;

[0015] The vehicles in the target vehicle set follow the front vehicle in turn to form a convoy until the status of each vehicle is consistent, that is, when the speed of the rear vehicle is adjusted to the same speed as the front vehicle and the distance between the two vehicles is greater than or equal to the minimum safe distance allowed for the rear vehicle to enter the convoy, it will follow the front vehicle to form a convoy.

[0016] Optionally, the minimum safe distance δ allowed to enter the convoy n The calculation formula is as follows:

[0017] δ n =|v n -v n-1 |t+∫0 t ∫0 t |a n (t)-a n-1 (t)|dtdt+S safe

[0018] In the formula, v n is the speed of the nth vehicle, v n-1 is the speed of the n-1th car, a n is the acceleration of the nth car, a n-1 is the acceleration of the n-1th vehicle, t is the speed adjustment time, Ssafe It is the minimum safe distance of the vehicle after braking.

[0019] Optionally, the fleet as a whole can be approximated as a rectangle.

[0020] Optionally, if there is a possibility of collision between straight-moving convoys and left-turning convoys, the convoy that arrives at the possible collision area first is controlled to have priority to pass, and the other convoy is controlled to pass later according to the principle of first come first served; if two convoys arrive at the possible collision area at the same time, the convoy that arrives at the intersection first is controlled to have priority to pass, and the other convoy is controlled to pass later; if two convoys arrive at the intersection at the same time, one of the convoys is selected to have priority to pass, and the other convoy is controlled to pass later;

[0021] If there is a possibility of collision between the straight-moving convoy and the left-turning convoy, determine whether the two convoys will collide when passing the intersection at the current speed; if so, the straight-moving convoy is controlled to have priority, and the left-turning convoy is controlled to pass later; if not, the convoy that arrives at the possible collision area first is controlled to have priority, and the other convoy is controlled to pass later, according to the principle of first come first served.

[0022] Optionally, when there is a possibility of collision between the straight-moving convoy and the left-turning convoy, the length L from the intersection to the possible collision area is calculated. R1 :

[0023]

[0024] Where, L s is the width of the vehicle body, L crossing is the distance from the center of the intersection to the vehicle stop line, R left is the left turn radius;

[0025] Calculate the time T for the straight-moving team to reach the possible collision area fleet1 :

[0026]

[0027] Where L1 is the distance between the straight-moving convoy and the intersection, and v1 is the speed of the straight-moving convoy;

[0028] Calculate the deflection angle θ of the left-turning team to reach the possible collision area fleet21 :

[0029]

[0030] Calculate the time T for the left-turning team to reach the possible collision area fleet21 :

[0031]

[0032] Where L2 is the distance between the left-turning convoy and the intersection, and v2 is the speed of the left-turning convoy;

[0033] Calculate the time T for the straight-moving team to leave the possible collision area fleet1k :

[0034]

[0035] Where, L fleet1 is the length of the straight convoy;

[0036] Calculate the deflection angle θ of the left-turning team leaving the possible collision area fleet22 :

[0037]

[0038] Calculate the time T for the left-turning team to leave the possible collision area fleet2k :

[0039]

[0040] Where, L fleet2 is the length of the left-turning convoy;

[0041] Assume that the straight-moving convoy reaches the possible collision area first, including:

[0042] ①When T fleet1 ≤T fleet21 ≤T fleet1k When the left-turning convoy arrives at the possible collision area before the straight-moving convoy has completely left the possible collision area, the left-turning convoy should react within the reaction time t re Then decelerate uniformly and at t x2 Arrive at the intersection at time T fleet1k The possible collision zone is reached at:

[0043]

[0044] In the formula, a2 is the acceleration of the left-turning convoy, and v is the speed when arriving at the intersection;

[0045] Each intersection has a maximum turning speed v max ; When v<v max When V>v max When V=v max ;

[0046] ②When T fleet1k ≤T fleet21 There is no risk of collision.

[0047] Optionally, when there is a possibility of collision between two straight-moving convoys, the time T′ when the first straight-moving convoy arrives at the possible collision area is calculated. fleet1 and the time T′ when the first straight-line vehicle group leaves the possible collision area fleet1k ;

[0048] Calculate the time T for the second straight-moving team to arrive at the possible collision area fleet31 and the time T when the second straight-moving team leaves the possible collision area fleet32 ;

[0049] ①When T′ fleet1 ≤T fleet31 ≤T′ fleet1k When the first straight-moving convoy arrives at the possible collision area first, the second straight-moving convoy should react within the reaction time t re Then it decelerates evenly to reach the intersection, and then moves at a constant speed at T′ fleet1k Arriving at the possible collision area at a speed v′ at a certain moment;

[0050] Each intersection has a maximum turning speed v max ; When v′<v max When v′>v max When V=v max ;

[0051] ②When T fleet31 ≥T′ fleet1k There is no risk of collision.

[0052] Optionally, when there is a possibility of collision between the left-turning convoy and the right-turning convoy, assuming that the first left-turning convoy reaches the possible collision area first, the second straight-moving convoy should re Then it decelerates evenly to reach the intersection, and then 4x Arriving at the possible collision area at a constant speed;

[0053] Each intersection has a maximum turning speed v max ; When v 4x <v max When V=v 4x ; When v 4x >v max When V=v max .

[0054] In a second aspect, the present invention further provides a vehicle dispatching system at a non-signal light intersection for implementing any one of the above-mentioned vehicle dispatching methods at a non-signal light intersection, comprising a vehicle-side terminal and an intelligent roadside terminal;

[0055] The vehicle terminal is installed on the vehicle, including a positioning module and a vehicle-mounted network communication terminal;

[0056] The intelligent roadside terminal is set at the intersection without traffic lights;

[0057] The positioning module is used to obtain the vehicle's location information and driving posture information, and send it to the on-board network communication terminal; the on-board network communication terminal is used for information exchange between the vehicle and other vehicles and the intelligent roadside terminal.

[0058] Optionally, the vehicle-side terminal also includes a human-computer interaction system, and the on-board network communication terminal transmits the vehicle control information sent by the intelligent roadside end to the human-computer interaction system. The human-computer interaction system is used to present the vehicle control information to the driver or directly control the vehicle through touch, hearing or vision.

[0059] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0060] The present invention makes full use of the C-V2X technology for vehicle-road collaboration to conduct vehicle collaborative decision-making control, allowing multiple vehicles to make collaborative decisions, and reasonably plan the execution plan to pass through intersections without signal lights, solving the problem of congestion and collision at intersections without signal lights in towns and villages. At the same time, this solution controls the formation of vehicles traveling on the lane based on the following model, and dispatches traffic intersections by controlling the fleet, ensuring the consistency of vehicles when passing through intersections, reducing frequent communications between vehicles and the roadside, and solving the problem of collisions caused by vehicles receiving instructions from the roadside due to long delays and inability to complete decision-making processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 A flow chart of a vehicle dispatching method at an intersection without a signal light;

[0062] Figure 2 This is a diagram of the vehicle-vehicle-roadside communication architecture;

[0063] Figure 3 This is a schematic diagram of the vehicle collision area at a traffic intersection;

[0064] Figure 4 This is a schematic diagram of a traffic intersection scene model;

[0065] Figure 5 Schematic diagram of the vehicle from deceleration to leaving the collision zone. DETAILED DESCRIPTION

[0066] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0067] The present invention makes full use of the C-V2X technology for vehicle-road collaboration to conduct vehicle collaborative decision-making control, allowing multiple vehicles to make collaborative decisions, and reasonably plan the execution plan to pass through intersections without signal lights, solving the problem of congestion and collision at intersections without signal lights in towns and villages. At the same time, this solution controls the formation of vehicles traveling on the lane based on the following model, and dispatches traffic intersections by controlling the fleet, ensuring the consistency of vehicles when passing through intersections, reducing frequent communications between vehicles and the roadside, and solving the problem of collisions caused by vehicles receiving instructions from the roadside due to long delays and inability to complete decision-making processing.

[0068] Example 1

[0069] The present invention provides a vehicle dispatching method at a non-signal intersection, such as Figure 1 As shown, the following steps are included:

[0070] Obtain vehicles waiting to pass at intersections without traffic lights and divide them into fleets;

[0071] Determine the two convoys closest to the intersection, and determine whether there is an overlapping area in the running trajectories of the two convoys when passing through the intersection;

[0072] If not, the two convoys will not collide, and the two convoys are controlled to pass through the intersection normally; since the two convoys will not collide, the two convoys can pass through the intersection normally, and in order to improve traffic efficiency, the two convoys can be accelerated to pass.

[0073] If yes, there is a possibility of collision between the two convoys, and the overlapping area is the possible collision area; and the time when the two convoys arrive at the possible collision area is calculated, and the convoy that arrives at the possible collision area first is controlled to pass first according to the principle of first come first served, and the other convoy is controlled to pass later;

[0074] Then calculate the time when the priority convoy leaves the possible collision area, and combine it with the time when the second convoy arrives at the possible collision area to determine whether the two convoys will collide when passing through the intersection at the current speed; if so, control the second convoy to slow down so that the time when the second convoy arrives at the possible collision area is exactly the time when the priority convoy leaves the possible collision area; if not, control the second convoy to accelerate so that the time when the second convoy arrives at the possible collision area is exactly the time when the priority convoy leaves the possible collision area, or control the second convoy to pass through the intersection normally. Since no collision will occur, the second convoy can pass through the intersection normally. In order to improve the traffic efficiency, the time when the second convoy arrives at the possible collision area can be exactly the time when the priority convoy leaves the possible collision area.

[0075] In some embodiments, the fleet is divided into:

[0076] Identify the lead vehicle;

[0077] Determine a set of target vehicles that have the same driving direction as the leader vehicle and are within a certain distance from the leader vehicle; the same driving direction includes the same current driving lane and the same target driving direction; the target driving direction includes left turn, straight ahead and right turn;

[0078] The vehicles in the target vehicle set follow the front vehicle in turn to form a convoy until the status of each vehicle is consistent, that is, when the speed of the rear vehicle is adjusted to the same speed as the front vehicle and the distance between the two vehicles is greater than or equal to the minimum safe distance allowed for the rear vehicle to enter the convoy, it will follow the front vehicle to form a convoy.

[0079] The minimum safe distance δ allowed to enter the convoy n The calculation formula is as follows:

[0080] δ n =|v n -v n-1 |t+∫0 t ∫0 t |a n (t)-a n-1 (t)|dtdt+s safe

[0081] In the formula, v n is the speed of the nth vehicle, v n-1 is the speed of the n-1th car, a n is the acceleration of the nth car, a n-1 is the acceleration of the n-1th vehicle, t is the speed adjustment time, S safe It is the minimum safe distance of the vehicle after braking.

[0082] For example, the vehicle at the front is usually the leading vehicle. If a vehicle cannot enter the previous convoy, it will be the leading vehicle of the next convoy. The same current driving lane means that the vehicle is in the same lane as the leading vehicle or can enter the lane currently driven by the leading vehicle; if these vehicles have the same target driving direction as the leading vehicle, they can be used as target vehicles. Since the speed of the vehicle is inconsistent with that of the target vehicle, when the speed of the rear vehicle is adjusted to the same speed as the front vehicle, the distance between the two vehicles is greater than or equal to the minimum safe distance allowed for the rear vehicle to enter the convoy, and the rear vehicle is allowed to follow the front vehicle to form a convoy.

[0083] In some optional embodiments, if the distance between the front and rear vehicles is too large, such as exceeding a preset distance value, including the distance before or after speed adjustment, the rear vehicle can be excluded to avoid wasting travel time and affecting travel efficiency due to the large distance between the front and rear vehicles.

[0084] In some embodiments, the vehicle fleet as a whole is approximated as a rectangle, thereby determining a collision area.

[0085] In some embodiments, the vehicle may also be controlled according to the straight-ahead priority principle, specifically:

[0086] If there is a possibility of collision between straight-moving convoys and left-turning convoys, the convoy that arrives at the possible collision area first will be given priority according to the principle of first come first served, and the other convoy will be controlled to pass later; if two convoys arrive at the possible collision area at the same time, the convoy that arrives at the intersection first will be given priority, and the other convoy will be controlled to pass later; if two convoys arrive at the intersection at the same time, one of the convoys will be given priority, and the other convoy will be controlled to pass later;

[0087] If there is a possibility of collision between the straight-moving convoy and the left-turning convoy, it is determined whether the two convoys will collide when passing through the intersection at the current speed; if so, the straight-moving convoy is given priority, and the left-turning convoy is controlled to pass later; if not, the convoy that first reaches the possible collision area is controlled to pass first according to the principle of first come first served, and the other convoy is controlled to pass later. That is, when the straight-moving convoy and the left-turning convoy are about to collide, even if the left-turning convoy reaches the collision area first, the straight-moving convoy is given priority, rather than the left-turning convoy according to the principle of first come first served.

[0088] In some embodiments, if a third convoy arrives, it is determined whether there is an overlapping area between the third convoy and the two convoys when they pass through the intersection; if there are more than two overlapping areas, the determination is continued; if there is only one overlapping area, the two convoys with overlapping areas are controlled in the same way. Similarly, the number of overlapping areas between the new convoy and the convoy passing through the intersection is determined. It is also possible to wait until the convoy with priority leaves the intersection before making the determination, but the traffic efficiency is not as good as the above method.

[0089] Example 2

[0090] The present invention provides a real-time vehicle dispatching system for intersections without signal lights based on vehicle-road collaboration, which is mainly composed of a vehicle-side terminal and an intelligent road side unit (RSU for short). The vehicle-side terminal includes a positioning module, an on-board network communication terminal (On Board Unit, OBU for short, also known as an on-board unit) and a human-machine interaction system (HMI for short). The positioning module is used to obtain the vehicle's location information and driving posture information and send it to the OBU. The OBU is used for data exchange between the car and other vehicles and the RSU, and can transmit the reminder information issued by the RSU to the HMI through the vehicle gateway. The HMI is used to present the reminder information to the driver through touch, hearing or vision. The RSU is used to sense the road traffic environment information within a certain range of the RSU and can broadcast the processed information to the OBU.

[0091] Figure 2 The architecture of the vehicle-to-vehicle-to-roadside direct communication system is given, which usually includes the following subsystems:

[0092] 1. Radio communication system - receiving and sending V2X PC5 signals.

[0093] 2. Antenna: to receive and send radio frequency signals.

[0094] 3. The information processing unit is mainly responsible for processing the data it receives and / or senses. The unit exchanges information with the V2X on-board communication terminals of other vehicles and the roadside V2X communication equipment.

[0095] In the first stage, when a vehicle is traveling in the RSU communication area at a traffic intersection, the vehicle transmits its own data to the RSU through C-V2X communication. The RSU collects statistics on the received vehicle information and guides the vehicle speed according to the current vehicle status information at the intersection. In traffic control without signal lights, the traffic volume changes dynamically, and vehicles and the roadside need to communicate frequently. During the dispatching process, information disorder or long message delays may occur, which is not conducive to the safe passage of vehicles through the intersection. Based on the following model, the vehicles traveling on the lane are controlled in formation, and the traffic intersection is dispatched by controlling the fleet, which ensures the consistency of vehicles when passing through the intersection and avoids collisions caused by vehicles receiving instructions from the roadside and failing to complete decision-making due to long delays.

[0096] In the second stage, the vehicle status information is analyzed based on the following model, and the leading vehicle on the lane is determined. Vehicles within a certain distance from the leading vehicle follow in turn to form a convoy until the status of each vehicle is consistent, that is, when the speed of the rear vehicle is adjusted to the same speed as the front vehicle, there will be no collision, that is:

[0097] d n -d n-1 ≥δ n

[0098] Where, d n is the distance between the nth vehicle and the intersection, δ n It is the minimum safe distance for vehicle formation.

[0099] To ensure that the rear vehicle does not collide with the front vehicle and adjusts to the same speed, the minimum distance δ n for:

[0100] δ n =|v n -v n-1 |t+∫0 t ∫0 t |a n (t)-a n-1 (t)|dtdt+S safe

[0101] In the formula, v n is the speed of the nth car, a n is the acceleration of the nth vehicle, t is the time, S safe The minimum safe distance of the vehicle after braking.

[0102] In the third stage, when vehicles pass through the intersection in the form of a convoy, in order to prevent collisions with convoys in other lanes, it is necessary to analyze the movement state of the convoy, and to reasonably recommend vehicle speeds by judging whether the convoy will collide when passing through the intersection. In order to improve the accuracy of the model, all possible collision areas of the intersection are obtained by analyzing the collision situations of vehicles from different directions when they run to the intersection. Taking the collision area as the research object, the time when vehicles from different directions reach the collision is analyzed, and vehicles are controlled according to the first-come-first-served and straight-ahead priority principles, and the speed at which vehicles safely pass through the intersection is calculated.

[0103] Based on the convoy following the model formation. Without considering the shape and size of the vehicle, the convoy is regarded as a mass point, which will produce a large error when calculating the conflict position between the two convoys, and it is not practical. Therefore, in order to improve the accuracy, the model is built according to the actual size of the convoy, the convoy is regarded as a whole, approximated as a rectangle, and the three-dimensional motion model of the vehicle is converted into a two-dimensional motion model, and the calculation results will be more accurate and objective.

[0104] In the fourth stage, this plan takes the cross intersection as the research object of traffic dispatch, such as Figure 3As shown in the figure, there are two lanes for left turn and straight driving in the four directions of the intersection, namely, the southeast, northwest and northeast. Since there is no possibility of collision with vehicles in other lanes when passing through the intersection, this direction is not studied. Determine the possible collision type of the two convoys closest to the traffic intersection when passing through the intersection, such as Figure 3 As shown, the distribution of collision areas when convoy 1 goes straight and convoy 2 turns left, convoy 1 goes straight and convoy 3 goes straight, and convoy 2 turns left and convoy 4 turns left. According to different types of collision areas, the speed of convoys with possible collision is guided to control the safe passage of the convoy through the intersection.

[0105] Although convoy 2 and convoy 3 meet the requirements of going straight and turning left, there is obviously no collision between the two convoys, so the two convoys can be controlled to pass through the intersection normally.

[0106] In the fifth stage, in order to improve the traffic efficiency at the intersection, the convoy needs to be guided at a reasonable speed. If the convoy will not collide when passing through the intersection, the convoy will pass through the intersection normally at the current speed; if there is a possibility of collision when the convoy passes through the intersection, the collision area of ​​the convoy is determined and the time to reach the collision area is calculated. According to the time when each convoy arrives at the collision area, the first convoy is given priority on the principle of first come first served and straight driving priority. When the second convoy arrives at the collision area, it must ensure that all vehicles of the first convoy to arrive safely leave the collision area. At this time, the time when the previous convoy leaves the collision area is the time when the next convoy arrives at the collision area, and the efficiency is the highest at this time.

[0107] The sixth stage analyzes the possible vehicle traffic conditions at the traffic intersection as follows:

[0108] Convoy 1 goes straight and Convoy 2 turns left. The collision zone of the two convoys is R ABCD First, we need to calculate the time it takes for convoy 1 and convoy 2 to reach the collision zone. Assume that the center of mass of the convoy is in the middle of the lane when the convoy is moving. The arc of convoy 2 when turning left is approximately regarded as a quarter circle arc, and the length L from the traffic intersection to the collision zone is calculated. R1 :

[0109]

[0110] Where, L s is the width of the vehicle body, L crossing is the distance from the center of the traffic intersection to the vehicle stop line, such as Figure 4 As shown,

[0111] The arc from the stop line to the departure line of the left-turning vehicle can be approximated as a quarter circle, with the radius denoted by R left :

[0112]

[0113] Calculate the time T for convoy 1 to reach the collision area at the current speed v1 fleet1 :

[0114]

[0115] Where L1 is the distance between convoy 1 and the traffic intersection.

[0116] The route of the convoy when it reaches the collision area is considered as an arc. Starting from the center position of the front vertex, the deflection angle θ of convoy 2 at the current speed v2 is calculated. fleet21 :

[0117]

[0118] The time T when convoy 2 arrives at the collision area fleet21 :

[0119]

[0120] Where L2 represents the distance between convoy 2 and the traffic intersection.

[0121] Next, calculate the time T when team 1 leaves the collision area fleet1k :

[0122]

[0123] Where, L fleet1 is the length of convoy 1, which is composed of different types of vehicles in the convoy and the safety distance between each vehicle.

[0124] The deflection angle θ of the convoy 2 leaving the collision area fleet22 :

[0125]

[0126] The time T when convoy 2 leaves the collision area fleet2k :

[0127]

[0128] Where, L fleet2 is the length of convoy 2.

[0129] Assume that convoy 1 enters the collision zone first. To allow convoy 1 to pass the intersection safely, convoy 2 must enter the collision zone after convoy 1 has completely left the collision zone. There are several possibilities:

[0130] ①When T fleet1 ≤T fleet21 ≤T fleet1kWhen , convoy 2 arrives at the collision zone when convoy 1 enters the collision zone but has not completely left it. Figure 5 As shown, fleet 2 needs a certain reaction time t when receiving the recommended speed from the roadside. re , which is generally 0.3 to 1.0 s. Therefore, from the time the fleet receives the command to the time it executes it, the vehicles should move at a constant speed for a certain distance and then decelerate evenly. x2 At the intersection, the vehicle enters the curve at a constant speed. fleet1k Always enter the collision zone.

[0131] According to the kinematic formula, Team 2 is at T fleet1k The internal movement process is based on Figure 5 As shown, we have:

[0132]

[0133] Where a2 represents the acceleration of team 2, t x2 is the time when convoy 2 enters the traffic intersection, and v is the speed at which convoy 2 enters the traffic intersection. Each intersection has a maximum turning speed v max When v<v max When V>v max When V=v max ;

[0134] ②When T fleet1k ≤T fleet21 When , convoy 2 enters the collision area after convoy 1 leaves the collision area, and there is no risk of collision.

[0135] In the seventh stage, convoy 1 and convoy 3 go straight, analyze the vehicle motion model, predict the vehicle's running trajectory and the status of arriving at the collision area, calculate the time for the first convoy to leave the collision area, and then calculate the reasonable speed for the second convoy to safely enter the collision area, and send message instructions to all vehicles in the second convoy through C-V2X communication.

[0136] Calculate the time T′ when the team 1 reaches the collision area at the current speed v1 fleet1 :

[0137]

[0138] Where, L s3 is the vehicle body width of fleet 3.

[0139] The time T′ when convoy 1 leaves the collision area fleet1k :

[0140]

[0141] Then calculate the time T for team 3 to reach the collision area at the current speed v3 fleet31 :

[0142]

[0143] The time T when convoy 3 leaves the collision area fleet32 :

[0144]

[0145] The time it takes for the straight-moving convoys to arrive at the collision area is compared, and the convoy that has priority in passing the collision area is determined based on the first-come, first-served principle. When the convoys arrive at the collision area at the same time, the lengths of the convoys themselves can also be compared, and the convoy with the shorter length will have priority.

[0146] ①When T′ fleet1 ≤T fleet31 ≤T′ fleet1k When , convoy 1 arrives at the collision area first, and convoy 3 arrives at the collision area by uniform deceleration. According to the kinematic formula, we have:

[0147]

[0148] Where, L R3 is the distance between convoy 3 and the collision zone, a3 is the acceleration of convoy 3, and v′ is the speed at which convoy 3 enters the traffic intersection. Each intersection has a maximum turning speed v max When v′<v max When v′>v max When V=v max .

[0149] ②When T fleet31 ≥T′ fleet1k When , convoy 3 enters the collision area after convoy 1 leaves the collision area, and there is no risk of collision.

[0150] In the eighth stage, convoy 2 and convoy 4 turn left, and the collision area of ​​the two convoys is R EFGH , assuming that team 2 arrives at the collision area first, calculate the deflection angle of team 2 arriving at the GF edge of the collision area as θ GF :

[0151]

[0152] The deflection angle θ when convoy 2 reaches the HE side of the collision area HE :

[0153]

[0154] Since the vehicle width is L s, the collision area is symmetrical about line EG, so the deflection angle of convoy 4 from entering the intersection to the collision area is 90°-θ HE , before entering the intersection, the first convoy will first perform a uniform deceleration linear motion (before entering the traffic intersection, the first convoy will avoid rollover when turning and need to decelerate to the maximum turning speed v max , and then make uniform circular motion through the traffic intersection), and the speed is reduced to v when entering the traffic intersection max The acceleration is a′2:

[0155]

[0156] And time t′2:

[0157]

[0158] The time t″2 from when convoy 2 enters the traffic intersection to when it leaves the collision area:

[0159]

[0160] The total departure time of team 2 is T2:

[0161] T2=t′2+t″2

[0162] In order to ensure that convoy 4 does not collide when it arrives at the collision zone, convoy 4 should enter the collision zone after convoy 2 leaves the collision zone. When convoy 4 receives the recommended speed from C-V2X communication, it will have a reaction time t re , then do uniform deceleration linear motion to reach the intersection, and then do uniform circular motion.

[0163] According to the kinematic formula, we have:

[0164]

[0165] Where t′4 is the time for the convoy 4 to perform uniform deceleration motion, t″4 is the time for the convoy 4 to perform uniform circular motion, and v 4x is the speed of the team 4 doing uniform circular motion, and a4 is the acceleration of the team 4 when doing uniform deceleration motion.

[0166] From the above formula, we can get the speed v of the vehicle when it turns into the intersection. 4x In order to ensure that the vehicle does not roll over when turning, it is necessary to determine v 4x With v max The size of v 4x <v max When V=v 4x ; When v 4x >v max When V=v max .

[0167] In summary, the present invention proposes a method for multiple vehicles to make collaborative decisions to pass through intersections without signal lights, thereby solving the problem of traffic collisions at intersections and improving traffic efficiency; a method for dispatching traffic intersections by controlling a fleet of vehicles, reducing frequent communications between vehicles and the roadside and thereby reducing communication delays, which can solve the problem of congestion and collisions at intersections without signal lights in towns and villages.

[0168] It should be noted that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0169] It should be pointed out that, according to the needs of implementation, the various steps / components described in this application can be split into more steps / components, and two or more steps / components or partial operations of steps / components can be combined into new steps / components to achieve the purpose of the present invention.

[0170] It will be easily understood by those skilled in the art that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A vehicle dispatching method at an intersection without a signal light, characterized in that: The following steps are involved: Obtain vehicles waiting to pass at intersections without traffic lights and divide them into fleets; Determine the two convoys closest to the intersection, and determine whether there is an overlapping area in the running trajectories of the two convoys when passing through the intersection; If not, the two convoys will not collide, and the two convoys are controlled to pass through the intersection normally; If yes, there is a possibility of collision between the two convoys, and the overlapping area is the possible collision area; and the time when the two convoys arrive at the possible collision area is calculated, and the convoy that arrives at the possible collision area first is controlled to pass first according to the principle of first come first served, and the other convoy is controlled to pass later; Then calculate the time when the priority convoy leaves the possible collision area, combined with the time when the rear convoy arrives at the possible collision area, to determine whether the two convoys will collide when passing the intersection at the current speed; if so, control the rear convoy to decelerate so that the time when the rear convoy arrives at the possible collision area is exactly the time when the priority convoy leaves the possible collision area; if not, control the rear convoy to accelerate so that the time when the rear convoy arrives at the possible collision area is exactly the time when the priority convoy leaves the possible collision area, or control the rear convoy to pass the intersection normally; When there is a possibility of collision between the straight-moving convoy and the left-turning convoy, the length L from the intersection to the possible collision area is calculated. R1 : Where, L s is the width of the vehicle body, L crossing is the distance from the center of the intersection to the vehicle stop line, R left is the left turn radius; Calculate the time T for the straight-moving team to reach the possible collision area fleet1 : Where L1 is the distance between the straight-moving convoy and the intersection, and v1 is the speed of the straight-moving convoy; Calculate the deflection angle θ of the left-turning team to reach the possible collision area fleet21 : Calculate the time T for the left-turning team to reach the possible collision area fleet21 : Where L2 is the distance between the left-turning convoy and the intersection, and v2 is the speed of the left-turning convoy; Calculate the time T for the straight-moving team to leave the possible collision area fleet1k : Where, L fleet1 is the length of the straight convoy; Calculate the deflection angle θ of the left-turning team leaving the possible collision area fleet22 : Calculate the time T for the left-turning team to leave the possible collision area fleet2k : Where, L fleet2 is the length of the left-turning convoy; Assume that the straight-moving convoy reaches the possible collision area first, including: ①When T fleet1 ≤T fleet21 ≤T fleet1k When the left-turning convoy arrives at the possible collision area before the straight-moving convoy has completely left the possible collision area, the left-turning convoy should react within the reaction time t re Then decelerate uniformly and at t x2 Arrive at the intersection at time T fleet1k The possible collision zone is reached at: Where a2 is the acceleration of the left-turning convoy, and v is the speed when arriving at the intersection; Each intersection has a maximum turning speed v max ; When v<v max When V>v max When V=v max ; ②When T fleet1k ≤T fleet21 There is no risk of collision.

2. The vehicle dispatching method at a non-signalized intersection according to claim 1, characterized in that: The fleet is divided into: Identify the lead vehicle; Determine a set of target vehicles that have the same driving direction as the leading vehicle and are within a preset distance value from the leading vehicle; the same driving direction includes the same current driving lane and the same target driving direction; the target driving direction includes left turn, straight ahead and right turn; The vehicles in the target vehicle set follow the front vehicle in turn to form a convoy until the status of each vehicle is consistent, that is, when the speed of the rear vehicle is adjusted to the same speed as the front vehicle and the distance between the two vehicles is greater than or equal to the minimum safe distance allowed for the rear vehicle to enter the convoy, it will follow the front vehicle to form a convoy.

3. The vehicle dispatching method at a non-signalized intersection according to claim 2, characterized in that: The minimum safe distance δ allowed to enter the convoy n The calculation formula is as follows: In the formula, v n is the speed of the nth vehicle, v n-1 is the speed of the n-1th car, a n is the acceleration of the nth car, a n-1 is the acceleration of the n-1th vehicle, t is the speed adjustment time, S safe It is the minimum safe distance of the vehicle after braking.

4. The vehicle dispatching method at a non-signalized intersection according to claim 1, characterized in that: The fleet as a whole is represented by a rectangle.

5. The vehicle dispatching method at a non-signalized intersection according to claim 1, characterized in that: If there is a possibility of collision between straight-moving convoys and left-turning convoys, the convoy that arrives at the possible collision area first will be given priority according to the principle of first come first served, and the other convoy will be controlled to pass later; if two convoys arrive at the possible collision area at the same time, the convoy that arrives at the intersection first will be given priority, and the other convoy will be controlled to pass later; if two convoys arrive at the intersection at the same time, one of the convoys will be given priority, and the other convoy will be controlled to pass later; If there is a possibility of collision between the straight-moving convoy and the left-turning convoy, determine whether the two convoys will collide when passing the intersection at the current speed; if so, the straight-moving convoy is controlled to have priority, and the left-turning convoy is controlled to pass later; if not, the convoy that arrives at the possible collision area first is controlled to have priority, and the other convoy is controlled to pass later, according to the principle of first come first served.

6. The vehicle dispatching method at a non-signalized intersection according to claim 1, characterized in that: When there is a possibility of collision between two straight-moving convoys, the time T for the first straight-moving convoy to reach the possible collision area is calculated. f ′ leet1 and the time T when the first straight convoy leaves the possible collision area f ′ leet1k ; Calculate the time T for the second straight-moving team to arrive at the possible collision area fleet31 and the time T when the second straight-moving team leaves the possible collision area fleet32 ; ①When T f ′ leet1 ≤T fleet31 ≤T f ′ leet1k When the first straight-moving convoy arrives at the possible collision area first, the second straight-moving convoy should react within the reaction time t re Then, it decelerates evenly to the intersection, and then moves at a constant speed at T f ′ leet1k At the speed v ′ reaching the possible collision area; Each intersection has a maximum turning speed v max ; When v ′ <v max When V=v ′ ; When v ′ >v max When V=v max ; ②When T fleet31 ≥T f ′ leet1k There is no risk of collision.

7. The vehicle dispatching method at a non-signalized intersection according to claim 1, characterized in that: When there is a possibility of collision between two left-turning convoys, assuming that the first left-turning convoy reaches the possible collision area first, the second straight-moving convoy should react within the reaction time t re Then it decelerates evenly to reach the intersection, and then 4x Arriving at the possible collision area at a constant speed; Each intersection has a maximum turning speed v max ; When v 4x <v max When V=v 4x ; When v 4x >v max When V=v max .

8. A vehicle dispatching system at a non-signalized intersection for implementing the vehicle dispatching method at a non-signalized intersection as claimed in any one of claims 1 to 7, characterized in that: Including vehicle-side terminal and intelligent roadside terminal; The vehicle terminal is installed on the vehicle, including a positioning module and a vehicle-mounted network communication terminal; The intelligent roadside terminal is set at the intersection without traffic lights; The positioning module is used to obtain the vehicle's location information and driving posture information, and send it to the vehicle-mounted network communication terminal; The on-board network communication terminal is used for information exchange between the vehicle and other vehicles as well as the intelligent roadside terminal.

9. The vehicle dispatching system at a non-signalized intersection according to claim 8, characterized in that: The vehicle-side terminal also includes a human-computer interaction system. The on-board networked communication terminal transmits the vehicle control information sent by the intelligent roadside end to the human-computer interaction system. The human-computer interaction system is used to present the vehicle control information to the driver or directly control the vehicle through touch, hearing or vision.

Images