A CAV lane-changing speed regulation method for expressway diverging area in a network environment

Abstract

The application discloses a CAV lane-changing speed regulation method for a freeway diverging area in a network environment, when a CAV travels in a free lane-changing area, if the CAV has a lane-changing demand and the acceptable gap of a target lane meets the requirement of a free-type lane-changing model, the CAV performs a lane-changing operation, otherwise, the vehicle continues to follow and travel forward; when the CAV enters a forced lane-changing area, it is first determined whether the CAV has a lane-changing demand, if not, the vehicle continues to follow and travel forward; if the destination of the CAV needs to perform forced lane-changing and the acceptable gap of the target lane does not meet the safety gap requirement of a forced-type lane-changing model, the CAV continues to keep a following state and performs speed adjustment to seek a suitable safety gap for lane-changing operation. The application can help to improve the lane-changing success rate of vehicles in the freeway diverging area, improve the traffic operation condition of the diverging area, thereby providing method support for traffic flow speed regulation of the freeway diverging area.

Description

Technical Field

[0001] This invention belongs to the field of intelligent connected vehicle traffic control, and particularly relates to the field of lane-changing speed control of connected autonomous vehicles in expressway diversion zones. Specifically, it is a method for controlling lane-changing speed of CAVs in expressway diversion zones under a connected environment. Background Technology

[0002] Expressways primarily serve rapid transit in cities, playing a vital transportation role and occupying a dominant position in urban traffic. Expressway diversion zones are crucial traffic nodes in the urban transportation system, functional areas for separating vehicle flow. Effective management of these diversion zones is critical to the overall traffic efficiency of the urban road network. With the continued rapid growth of motor vehicle traffic demand in my country, prolonged traffic congestion in expressway diversion zones has become commonplace in many large cities, severely impacting residents' travel quality and reducing urban traffic efficiency.

[0003] With the development of 5G and vehicle-to-everything (V2X) technologies, vehicles are becoming increasingly connected and automated. In the future, all vehicles on the road will be connected and autonomous. These connected and autonomous vehicles can not only communicate with each other but also connect with intelligent transportation equipment on the road to obtain real-time road information. Conflicts caused by lane changes in expressway divergence zones affect the stable operation of traffic flow, reduce lane-changing efficiency, and increase the risk of lane changes and accidents. Summary of the Invention

[0004] This invention overcomes the shortcomings of existing technologies and proposes a method for controlling lane-changing speed in the CAV (Carrier-to-Area Vehicle) of a fast road divergence zone under a connected environment. The aim is to adjust the speed of vehicles located in the forced lane-changing area and with lane-changing needs, while ensuring safe vehicle operation, in order to find a suitable safe lane-changing gap for lane-changing operations, thereby improving the success rate of lane-changing and further improving the safety and efficiency of traffic flow in the fast road divergence zone.

[0005] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0006] The present invention discloses a method for controlling the lane-changing speed of CAVs in a fast road divergence zone under a connected environment. The method involves designating all vehicles in the three lanes in one direction of the fast road as connected autonomous vehicles (CAVs). The three lanes are designated as lane 1, lane 2, and lane 3 from the inside out. A deceleration lane is located outside lane 3 and designated as lane 4. An exit ramp is located ahead of the deceleration lane. The road area with an upstream length of 's' of the exit ramp is defined as the fast road divergence zone. The CAV lane-changing speed control method includes the following steps:

[0007] Step 1: Establish a road coordinate system with the end of the road centerline of the deceleration lane as the origin x0, the vehicle's direction of travel as the positive x-axis, and the direction perpendicular to the x-axis as the y-axis.

[0008] Starting from the origin x0, with the x-coordinate x m The road area of ​​length M bounded by the endpoint is designated as the forced lane-changing area; the x-coordinate is used as the boundary. m Starting from the upstream road, the area covered by the free lane-changing zone is defined as the area upstream of the road.

[0009] Let any lane be designated as lane i. In the free lane-changing area, let i = 1, 2; in the forced lane-changing area, let i = 1, 2, 3.

[0010] Step 2: Collect vehicle information for the three lanes in one direction on the expressway at time t, including: number of vehicles, vehicle position, speed, and acceleration;

[0011] Step 3: Based on the vehicle position, determine the nth vehicle in the i-th lane at time t. Is it located in a free lane-changing area? If yes, proceed to step 4; otherwise, proceed to step 6.

[0012] Step 4: Determine the nth vehicle in lane i. Is there a lane change requirement? If so, proceed to step 5; otherwise, Continue following the car and proceed to step 11;

[0013] Step 5: Let the nth car in lane i be at time t. The car in front is recorded as It will be in lane i+1, and relative to the nth car in lane i. The next car is recorded as It will be in the (i+1)th lane, and relative to the nth car in the i-th lane. The car in front is recorded as

[0014] Determine the nth vehicle in lane i at time t. Does it satisfy the free lane-changing condition shown in equation (1)? If it does, then Change lanes to lane i+1 and proceed to step 11; otherwise, Continue following the car and proceed to step 11;

[0015]

[0016] In formula (1): Let n be the nth car in lane i at time t. The vehicle in front in the current lane distance, Let n be the nth car in lane i at time t. speed, Let n be the nth car in lane i at time t. acceleration, t lc v is the duration of a vehicle changing lanes. max This is the maximum speed of the main line of the expressway. Let n be the nth car in lane i at time t. The vehicle in front in lane i+1 distance, Let n be the nth car in lane i at time t. The car in front speed, Let n be the nth car in lane i at time t. The vehicle behind in lane i+1 distance, Let n be the nth car in lane i at time t. The safe lane-changing clearance is obtained from equation (2). Let n be the nth car in lane i at time t. The expected speed is obtained through equation (3);

[0017]

[0018] In equation (2), μ is the safety factor, 0 ≤ μ ≤ 1. Let's consider the vehicle behind in lane i+1 at time t. speed;

[0019]

[0020] In equation (3), Let n be the nth car in lane i at time t. The distance L between the starting point of the exit ramp and the exit ramp r The lane-changing range for vehicles; v ramp The speed of the vehicle on the exit ramp;

[0021] Step 6: Determine the nth vehicle in lane i at time t. Is there a lane-changing requirement due to traffic diversion? If yes, proceed to step 7; otherwise, Continue following the car and proceed to step 11;

[0022] Step 7: Determine the nth car in lane i at time t. Does it satisfy the free lane-changing condition of equation (1)? If it does, then Change lanes to lane i+1 and proceed to step 11; otherwise, proceed to step 8 sequentially.

[0023] Step 8: Obtain the nth car in lane i at time t. The vehicle in front in lane i+1 distance The nth car in lane i at time t The vehicle behind in lane i+1 distance The vehicle behind in lane i+1 at time t speed The nth car in lane i velocity at time t

[0024] Step 9: Use equation (4) to calculate the nth vehicle in lane i at time t. Rear safety lane change clearance and front safety lane change clearance

[0025]

[0026] In equation (4): α and β are parameters, l veh Δt represents the vehicle body length, and Δt represents the time interval.

[0027] Step 10, Gap Judgment:

[0028] when and At time t, the nth vehicle in lane i is represented. Meet the safety clearance requirements for lane changes. Change lanes to lane i+1;

[0029] when and At time t, the nth vehicle in lane i is represented. A deceleration operation is required to obtain a safe clearance before the target, and this clearance is obtained using equations (5) and (6). deceleration Thus making according to Perform a deceleration operation;

[0030]

[0031] In equation (5): a dec For CAV maximum deceleration, For the nth car in lane i The desired velocity at time t+Δt after deceleration is obtained from equation (6):

[0032]

[0033] when and At time t, the nth vehicle in lane i is represented. An acceleration operation is required to obtain a rear safety clearance, and equations (7) and (8) are used to obtain... acceleration Thus making according to Perform an acceleration operation;

[0034]

[0035] In equation (7): a acc The maximum acceleration of CAV. For the nth car in lane i The expected velocity at time t+Δt after acceleration is obtained from equation (8);

[0036]

[0037] when and At time t, the nth vehicle in lane i is represented. A deceleration operation is required to facilitate Find the lane change clearance within t+Δt and obtain it using equation (9). deceleration Thus making according to Perform a deceleration operation;

[0038]

[0039] Step 11: Assign t + Δt to t, and determine if t ≥ t. o If the condition is met, speed adjustment is complete; otherwise, return to step 2 and execute sequentially. Where t... o Indicates the total control duration.

[0040] The present invention provides an electronic device, including a memory and a processor, wherein the memory is used to store a program that supports the processor in executing the traffic flow speed control method, and the processor is configured to execute the program stored in the memory.

[0041] The present invention discloses a computer-readable storage medium on which a computer program is stored, wherein the computer program, when executed by a processor, performs the steps of the traffic flow speed control method.

[0042] Compared with existing technologies, the beneficial technical effects of this invention are reflected in:

[0043] 1. In the context of vehicle networking, this invention enables vehicles to more accurately perceive their surroundings, identify their location, determine their lane-changing intentions and whether lane-changing conditions are met, and conduct intelligent information exchange and intelligent decision-making. This achieves dynamic control of vehicle driving status, which helps improve road traffic efficiency, avoids traffic congestion and accidents, and ensures safe vehicle operation.

[0044] 2. This invention can determine a vehicle's intention to change lanes and whether the lane-changing conditions are met. If the destination to which the CAV is heading requires a forced lane change and the acceptable clearance of the target lane does not meet the safety clearance requirements of the forced lane-changing model, the CAV will adjust its own speed according to the speed of the vehicle in front, the speed of the vehicle behind, and the clearance between the two vehicles in the target lane to find a lane-changing opportunity. This helps to improve the success rate of lane changes and the efficiency of road traffic, and reduces traffic congestion.

[0045] 3. Compared with the prior art, the present invention continuously re-collects vehicle information at a certain time step and updates the CAV position, lane-changing intention and conditions in real time according to the real-time traffic conditions, thereby improving the lane-changing efficiency and lane-changing success rate of vehicles in the expressway diversion area. Attached Figure Description

[0046] Figure 1 This is the overall flowchart of the present invention;

[0047] Figure 2 This is a flowchart of the control method of the present invention;

[0048] Figure 3 This is a schematic diagram of a scenario according to the present invention.

[0049] Figure 4 Comparison chart before and after adding speed adjustment model. Detailed Implementation

[0050] In this embodiment, a method for controlling the lane-changing speed of a Car Access Vehicle (CAV) in a fast road divergence zone under a connected environment is proposed. This method regulates the speed of CAV lane changes in the fast road divergence zone. If the CAV cannot find a suitable safe gap for lane changing within the forced lane-changing area, it will adjust its own speed based on the speeds of the preceding and following vehicles in the target lane, as well as the gap between the two vehicles, to find a lane-changing opportunity. This improves the success rate and efficiency of CAV lane changes in the fast road divergence zone, further enhancing traffic efficiency and safety. Specifically, as shown... Figure 1 and Figure 2 As shown, the method includes the following steps:

[0051] Step 1, as follows Figure 3 As shown, a road coordinate system is established with the end of the road centerline of the deceleration lane as the origin x0, the vehicle's direction of travel as the positive direction of the x-axis, and the direction perpendicular to the x-axis as the y-axis direction.

[0052] Starting from the origin x0, with the x-coordinate x m The road area of ​​length M bounded by the endpoint is designated as the forced lane-changing area; the x-coordinate is used as the boundary. m Starting from the upstream road, the area covered by the free lane-changing zone is defined as the area upstream of the road.

[0053] Let any lane be designated as lane i. In the free lane-changing area, let i = 1, 2; in the forced lane-changing area, let i = 1, 2, 3.

[0054] Step 2, as follows Figure 3 As shown, at time t, all vehicles on the expressway are connected autonomous vehicles. The CAV is equipped with an onboard perception system that can sense changes in the surrounding traffic environment. The roadside intelligent transportation equipment collects vehicle information for the three lanes in one direction on the expressway at time t, including: number of vehicles, vehicle position, speed, and acceleration. In this embodiment, the intelligent roadside intelligent transportation equipment is evenly distributed on both sides of the road and interacts with the CAV in real time through wireless network communication.

[0055] Step 3: Based on the vehicle position, determine the nth vehicle in the i-th lane at time t. Is it located in a free lane-changing area? If yes, proceed to step 4; otherwise, proceed to step 6.

[0056] Step 4: Determine the nth vehicle in lane i. Is there a lane change requirement? If so, proceed to step 5; otherwise, Continue following the car and proceed to step 11;

[0057] Step 5: Let the nth car in lane i be at time t. The car in front is recorded as It will be in lane i+1, and relative to the nth car in lane i. The next car is recorded as It will be in the (i+1)th lane, and relative to the nth car in the i-th lane. The car in front is recorded as

[0058] Determine the nth vehicle in lane i at time t. Does it satisfy the free lane-changing condition shown in equation (1)? If it does, then Change lanes to lane i+1 and proceed to step 11; otherwise, Continue following the car and proceed to step 11;

[0059]

[0060] In formula (1): Let n be the nth car in lane i at time t. The vehicle in front in the current lane distance, Let n be the nth car in lane i at time t. speed, Let n be the nth car in lane i at time t. acceleration, t lc v is the duration of a vehicle changing lanes. max This is the maximum speed of the main line of the expressway. Let n be the nth car in lane i at time t. The vehicle in front in lane i+1 distance, Let n be the nth car in lane i at time t. The car in front speed, Let n be the nth car in lane i at time t. The vehicle behind in lane i+1 distance, Let n be the nth car in lane i at time t. The safe lane-changing clearance is obtained from equation (2). Let n be the nth car in lane i at time t. The expected speed is obtained through equation (3);

[0061]

[0062] Both the most conservative and the most aggressive lane-changing clearances are unscientific. In order to balance efficiency and safety, the model introduces a safety factor μ to balance these two clearances, and constructs Equation (2) to determine the safe lane-changing clearance for CAVs during free lane changing.

[0063] In equation (2), μ is the safety factor, 0 ≤ μ ≤ 1. Let's consider the vehicle behind in lane i+1 at time t. speed;

[0064]

[0065] In equation (3), Let n be the nth car in lane i at time t. The distance L between the starting point of the exit ramp and the exit ramp r The lane-changing range for vehicles; v ramp The speed of the vehicle on the exit ramp;

[0066] Step 6, as follows Figure 2 As shown, determine the nth vehicle in lane i at time t. Is there a lane-changing requirement due to traffic diversion? If yes, proceed to step 7; otherwise, Continue following the car and proceed to step 11;

[0067] Step 7: Determine the nth car in lane i at time t. Does it satisfy the free lane-changing condition of equation (1)? If it does, then Change lanes to lane i+1 and proceed to step 11; otherwise, proceed to step 8 sequentially.

[0068] Step 8: Obtain the nth car in lane i at time t. The vehicle in front in lane i+1 distance The nth car in lane i at time t The vehicle behind in lane i+1 distance The vehicle behind in lane i+1 at time t speed The nth car in lane i velocity at time t

[0069] Step 9: Use equation (4) to calculate the nth vehicle in lane i at time t. Rear safety lane change clearance and front safety lane change clearance

[0070]

[0071] In equation (4): α and β are parameters, α takes the value of 3, β takes the value of 10, l veh Δt represents the vehicle body length, and Δt represents the time interval.

[0072] Step 10, Gap Judgment:

[0073] when and At time t, the nth vehicle in lane i is represented. Meet the safety clearance requirements for lane changes. Change lanes to lane i+1 and proceed to step 11;

[0074] when and At time t, the nth vehicle in lane i is represented. A deceleration operation is required to obtain a safe clearance before the target, and this clearance is obtained using equations (5) and (6). deceleration Thus making according to Perform a deceleration operation and proceed to step 11;

[0075]

[0076] In equation (5): a dec For CAV maximum deceleration, For the nth car in lane i The desired velocity at time t+Δt after deceleration is obtained from equation (6):

[0077]

[0078] when and At time t, the nth vehicle in lane i is represented. An acceleration operation is required to obtain a rear safety clearance, and equations (7) and (8) are used to obtain... acceleration Thus making according to Perform the acceleration operation and proceed to step 11;

[0079]

[0080] In equation (7): a acc The maximum acceleration of CAV. For the nth car in lane i The expected velocity at time t+Δt after acceleration is obtained from equation (8);

[0081]

[0082] when and At time t, the nth vehicle in lane i is represented. A deceleration operation is required to facilitate Find the lane change clearance within t+Δt and obtain it using equation (9). deceleration Thus making according to Perform a deceleration operation and proceed to step 11;

[0083]

[0084] Step 11: Assign t + Δt to t, and determine if t ≥ t. o If the condition is met, speed adjustment is complete; otherwise, return to step 2 and execute sequentially. Where t... o Indicates the total control duration.

[0085] In this embodiment, an electronic device includes a memory and a processor. The memory stores a program that supports the processor in executing the above-described method, and the processor is configured to execute the program stored in the memory.

[0086] In this embodiment, a computer-readable storage medium stores a computer program, which is executed by a processor to perform the steps of the above method.

[0087] like Figure 3 As shown, this embodiment conducts a numerical simulation experiment in a scenario with three lanes on the main road and a deceleration lane length of 240m, with upstream and downstream lengths of 500m each, to explore the effect of adding a speed adjustment model to the CAV forced lane change model. To avoid the randomness of experimental data, a total of 3 experiments were conducted and their average values ​​were calculated. The experimental results are as follows: Figure 4 As shown in the figure, the lane-changing success rate increased in all three experiments when the speed adjustment model was added compared to when it was not. The average of the three experiments shows that the lane-changing success rate increased by 17.58% when the speed adjustment model was added compared to when it was not.

Claims

1. A method for controlling lane-changing speed in the CAV (Cross-Area Vehicle) of a rapid transit zone under a connected environment, characterized in that, All vehicles in the three lanes of the expressway in one direction are connected autonomous vehicles (CAVs). The three lanes in one direction are designated as lane 1, lane 2, and lane 3 from the inside out. A deceleration lane is set outside lane 3 and designated as lane 4. An exit ramp is set in front of the deceleration lane. The road area with an upstream length of s of the exit ramp is designated as the expressway diversion zone. The CAV lane-changing speed control method includes the following steps: Step 1: Take the end of the road centerline of the deceleration lane as the origin. A road coordinate system is established with the vehicle's direction of travel as the positive x-axis and the direction perpendicular to the x-axis as the y-axis. From the origin Starting from the x-axis, The road area of ​​length M bounded by the endpoint is designated as the forced lane-changing area; the x-axis is used as the coordinate. Starting from the upstream road, the area covered by the free lane-changing zone is defined as the area upstream of the road. Let any lane be designated as lane i. In the free lane-changing area, let i = 1, 2; in the forced lane-changing area, let i = 1, 2, 3. Step 2: Collect vehicle information for the three lanes in one direction on the expressway at time t, including: number of vehicles, vehicle position, speed, and acceleration; Step 3: Based on the vehicle position, determine the nth vehicle in the i-th lane at time t. Is it located in a free lane-changing area? If yes, proceed to step 4; otherwise, proceed to step 6. Step 4: Determine the nth vehicle in lane i. Is there a lane change requirement? If so, proceed to step 5; otherwise, Continue following the car and proceed to step 11; Step 5: Let the nth car in lane i be at time t. The car before it is recorded as It will be in lane i+1, and relative to the nth car in lane i. The next car is recorded as It will be in the (i+1)th lane, and relative to the nth car in the i-th lane. The car before it is recorded as ; Determine the nth vehicle in lane i at time t. Does it satisfy the free lane-changing condition shown in equation (1)? If it does, then Change lanes to lane i+1 and proceed to step 11; otherwise, Continue following the car and proceed to step 11; (1) In formula (1): Let n be the nth car in lane i at time t. The vehicle in front in the current lane distance, Let n be the nth car in lane i at time t. speed, Let n be the nth car in lane i at time t. acceleration, The duration of the lane change. This is the maximum speed of the main line of the expressway. Let n be the nth car in lane i at time t. The vehicle in front in lane i+1 distance, Let n be the nth car in lane i at time t. The car in front speed, Let n be the nth car in lane i at time t. The vehicle behind in lane i+1 distance, Let n be the nth car in lane i at time t. The safe lane-changing clearance is obtained from equation (2). Let n be the nth car in lane i at time t. The expected speed is obtained through equation (3); (2) In equation (2), As a safety factor, , Let's consider the vehicle behind in lane i+1 at time t. speed; (3) In equation (3), Let n be the nth car in lane i at time t. The distance between the starting point of the exit ramp and the exit ramp. The lane-changing range for vehicles; The speed of the vehicle on the exit ramp; Step 6: Determine the nth vehicle in lane i at time t. Is there a lane-changing requirement due to traffic diversion? If yes, proceed to step 7; otherwise, Continue following the car and proceed to step 11; Step 7: Determine the nth car in lane i at time t. Does it satisfy the free lane-changing condition of equation (1)? If it does, then Change lanes to lane i+1 and proceed to step 11; otherwise, proceed to step 8 sequentially. Step 8: Obtain the nth car in lane i at time t. The vehicle in front in lane i+1 distance The nth car in lane i at time t The vehicle behind in lane i+1 distance The vehicle following in lane i+1 at time t speed The nth car in lane i velocity at time t ; Step 9: Use equation (4) to calculate the nth vehicle in lane i at time t. Rear safety lane change clearance and front safety lane change clearance ; (4) In equation (4): , For parameters, Indicates the length of the vehicle body. Indicates a time interval; Step 10, Gap Judgment: when and At time t, the nth vehicle in lane i is represented. Meet the safety clearance requirements for lane changes. Change lanes to lane i+1; when and At time t, the nth vehicle in lane i is represented. A deceleration operation is required to obtain a safe clearance before the target, and this clearance is obtained using equations (5) and (6). deceleration Thus making according to Perform a deceleration operation; (5) In equation (5): For CAV maximum deceleration, For the nth car in lane i After deceleration The expected velocity at time t is obtained from equation (6): (6) when and At time t, the nth vehicle in lane i is represented. An acceleration operation is required to obtain a rear safety clearance, and equations (7) and (8) are used to obtain... acceleration Thus making according to Perform an acceleration operation; (7) In equation (7): The maximum acceleration of CAV. For the nth car in lane i After acceleration The expected velocity at time t is obtained from equation (8); (8) when and At time t, the nth vehicle in lane i is represented. A deceleration operation is required to facilitate exist Find the lane change gap inside and use equation (9) to obtain deceleration Thus making according to Perform a deceleration operation; (9) Step 11, Assign to ,judge If the condition is met, speed adjustment is complete; otherwise, return to step 2 and execute sequentially. Indicates the total control duration.

2. An electronic device, comprising a memory and a processor, characterized in that, The memory is used to store a program that supports the processor in executing the CAV lane-changing speed control method for expressway divergence zones in a networked environment as described in claim 1, and the processor is configured to execute the program stored in the memory.

3. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is run by the processor, it executes the steps of the CAV lane-changing speed control method for expressway divergence zones in a networked environment as described in claim 1.

Images