An emergency vehicle turning coordination control method in a networked environment

Abstract

The application discloses a kind of emergency vehicle U-turn cooperative control methods under network environment, comprising:1, the vehicle information of t time is collected;2, judge whether there is emergency vehicle needing U-turn;3, determine the length of time that emergency vehicle needing U-turn reaches U-turn point and U-turns into opposite lane;4, execute opposite vehicle cooperative control strategy.The application can realize the safe U-turn of emergency vehicle in U-turn section, reduce vehicle delay, improve road traffic capacity by the information interaction between network vehicle and roadside facilities, network vehicle and network vehicle under network environment under the premise of guaranteeing traffic operation safety.

Description

Technical Field

[0001] This invention belongs to the field of intelligent connected vehicle traffic control, and particularly relates to the field of speed control of connected autonomous vehicles in urban road U-turn areas. Specifically, it is a collaborative control method for emergency vehicles turning around in road U-turn areas under a connected environment. Background Technology

[0002] 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. Currently, scholars have conducted extensive research on merging control at intersections and ramps, but less on U-turn areas. The merging behavior of vehicles making U-turns in U-turn areas shares similarities with other merging behaviors in that they are all based on gaps for lane changes. The difference lies in the speed evolution of U-turning vehicles, which differs from other merging scenarios and involves lane-changing actions. Therefore, safety accidents and traffic congestion often occur in U-turn areas. Traffic management departments guide vehicles through speed limits and yielding, but due to individual differences among drivers, the response to guidance strategies varies, resulting in limited effectiveness. Summary of the Invention

[0003] This invention overcomes the shortcomings of existing technologies and proposes a collaborative control method for emergency vehicles making U-turns in U-turn areas of road sections under a connected environment. The aim is to control the speed of the CAV (Carrier Air Vehicle) in the opposite lane of the U-turn area of ​​the road section while ensuring the safe driving of vehicles, so as to provide sufficient U-turn space for emergency vehicles preparing to make U-turns in the same direction, thereby improving the safety and efficiency of traffic flow in the U-turn area of ​​the road section.

[0004] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0005] The present invention discloses a collaborative control method for emergency vehicle U-turns in a connected environment, characterized in that it is applied to a two-way four-lane U-turn section, wherein a one-way U-turn lane is provided in the median strip of the U-turn section, and the vehicles in the connected environment are all connected autonomous vehicles. The collaborative control method for U-turns includes the following steps:

[0006] Step 1: In a two-way four-lane U-turn section, the lanes traveling in the same direction as the emergency vehicle needing to make a U-turn are numbered sequentially from the inside out as the third lane and the fourth lane, and the lanes traveling in the opposite direction to the emergency vehicle are numbered sequentially from the outside in as the first lane and the second lane; the center point of the one-way U-turn lane is the U-turn point of the emergency vehicle, the U-turn point is the origin x0, the direction of travel of the emergency vehicle is the positive x-axis, and the direction perpendicular to the x-axis is the y-axis, to establish a road coordinate system;

[0007] On the third lane, starting from the origin x0, with the x-coordinate x l The road area enclosed by the endpoint is used as the pre-turn-around area for emergency vehicles, and the length L of the pre-turn-around area is determined using equation (1):

[0008]

[0009] In equation (1), v max Indicates the maximum speed limit on the road; v ev-turn-max This indicates the maximum safe U-turn speed of the emergency vehicle; a ev-down-max This indicates the maximum safe deceleration of the emergency vehicle;

[0010] On the second lane, starting from the origin x0, with the x-coordinate x m The road area enclosed by the endpoint is designated as the oncoming vehicle control area, and the length M of the oncoming vehicle control area is determined using equation (2):

[0011]

[0012] In equation (2), a down-max This indicates the maximum safe deceleration of a connected autonomous vehicle;

[0013] Step 2: Use roadside intelligent transportation equipment to collect vehicle information in the second and third lanes at time t, including: vehicle type, number of vehicles, vehicle length, vehicle position, speed, and acceleration;

[0014] Step 3: Determine if there is an emergency vehicle that needs to make a U-turn in the third lane. If there is, proceed to step 4; otherwise, assign t+Δt to t and return to step 2 to execute sequentially, where Δt is the time update step size.

[0015] Step 4: Determine whether equation (3) is true. If it is true, it means that the emergency vehicle that needs to make a U-turn arrives at the pre-U-turn area at time t0 and reaches the maximum speed limit v of the road. max If the emergency vehicle that needs to make a U-turn arrives at the pre-U-turn area at time t0 but does not reach the maximum speed limit v of the road, then proceed with step 5.1. Otherwise, it indicates that the emergency vehicle that needs to make a U-turn arrived at the pre-U-turn area at time t0 but did not reach the maximum speed limit v of the road. max Then proceed to step 5.2;

[0016]

[0017] In equation (3), This indicates the speed of the emergency vehicle that needs to make a U-turn when it arrives at the pre-U-turn area at time t0;

[0018] Step 5: Calculate the time T required for the emergency vehicle that needs to make a U-turn to reach the U-turn point and merge into the second lane.总 ;

[0019] Step 5.1: Emergency vehicles that need to turn around should decelerate at the maximum safe speed a. ev-down-max The vehicle slows down and travels to the origin x0, and the time T required for the emergency vehicle to reach the origin x0 is calculated according to equation (4). ev Then, proceed to step 5.4;

[0020]

[0021] Step 5.2: Calculate the maximum acceleration a of the emergency vehicle that needs to turn around within the pre-turn-around area according to equation (5). ev-up-max The maximum intermediate speed v that can be achieved by acceleration ev-middle-max ;

[0022]

[0023] Step 5.3: Calculate the maximum acceleration a of the emergency vehicle that needs to turn around according to equation (6). ev-up-max First accelerate to the maximum intermediate speed v ev-middle-max Then decelerate at the maximum safe rate a ev-down-max The time T required to decelerate back to the origin x0 ev ;

[0024]

[0025] Step 5.4: Calculate the time T required for the emergency vehicle that needs to make a U-turn to travel from the pre-U-turn area to the origin x0 and then make a U-turn to merge into the second lane, according to formula (7). 总 ;

[0026] T 总 =T ev +T ev-turn-min (7)

[0027] In equation (7), T ev-turn-min This indicates the shortest time required for an emergency vehicle to make a U-turn and merge into the second lane.

[0028] Step 6: Execute the oncoming vehicle cooperative control strategy. Number the vehicles in the oncoming vehicle control area at time t0 in order of distance from the front of the vehicle to the origin x0, from closest to farthest, as 1, 2, ..., n.

[0029] Step 7: Iterate through each vehicle within the control area of ​​the opposing vehicle. For the i-th vehicle, i∈[1,n], determine whether equation (8) holds. If it holds, it indicates that the vehicle is within the control period [t0,t0+T]. 总At the end of the period, if the i-th vehicle conflicts with an emergency vehicle that needs to turn around, the number of the conflicting vehicle is recorded in set I; if none of the conflicts occur, it indicates that the control period [t0, t0+T] is complete. 总 At the end of the process, there is no conflict between all vehicles in the oncoming vehicle control area and the emergency vehicle that needs to make a U-turn. All vehicles in the oncoming vehicle control area continue to drive according to the state at time t0 until the emergency vehicle that needs to make a U-turn merges into the second lane, and the process ends.

[0030]

[0031] In equation (8), Let x represent the x-coordinate of the position of the front of the i-th vehicle at time t0; Let l represent the velocity of the i-th vehicle at time t0; ev The symbol 'l' represents the body length of the emergency vehicle; 'l' represents the body length of the connected autonomous vehicle; L min Indicates the minimum safe following distance;

[0032] Step 8: Denote the vehicle with the smallest number value in set I as the j-th vehicle;

[0033] Step 9: Determine whether equation (9) is true. If it is not true, it means that the j-th vehicle did not reach the maximum speed limit v at time t0. max If yes, proceed to step 10; otherwise, proceed to step 17.

[0034]

[0035] In equation (9), This represents the speed of the j-th vehicle at the initial control time t0;

[0036] Step 10: If j≥2, the first vehicle in the first j-1 vehicles in the opposing vehicle control area maintains the speed at time t0 and drives at a constant speed. The remaining j-2 vehicles follow the first vehicle and form a platoon according to the CACC car-following model shown in equation (10), and then execute step 11; otherwise, execute step 17.

[0037]

[0038] In equation (10), Δx w Let w represent the headway between any w-th vehicle among the first j-1 vehicles and the vehicle in front of it at time t1, where w > 1 and t1 ∈ [t0, t0 + T]. 总 ]; e w Indicate Δx w The difference between the expected front-end spacing and the desired front-end spacing; t c The desired headway; v w,prewLet k be the speed of vehicle w at time t1 before time t1; p k is the control parameter for the difference in frontage distance. d The differential control parameter for the difference in frontage distance; v w This represents the speed of the w-th vehicle;

[0039] Step 11: Calculate the x-coordinate of the head position of the (j-1)th vehicle after formation according to formula (11).

[0040]

[0041] In equation (11), The x-coordinate represents the position of the front of the first vehicle within the control area of ​​the opposing vehicle at time t0; This represents the speed of the first vehicle within the control area of ​​the oncoming vehicle at time t0; This indicates the time required for the first j-1 vehicles in the opposing vehicle control area to complete their formation;

[0042] Step 12: Calculate the x-coordinate of the head position of the j-th car after the first j-1 cars are convoyed according to formula (12).

[0043]

[0044] In equation (12), The x-coordinate represents the position of the j-th vehicle's front end at time t0;

[0045] Step 13: Determine whether equation (13) is true. If it is true, it means that after the first j-1 cars are grouped together, the jth car will not conflict with it, and proceed to step 14; otherwise, proceed to step 17.

[0046]

[0047] Step 14: Determine whether the j-th vehicle has sufficient acceleration space;

[0048] when When this occurs, it indicates that the j-th vehicle has sufficient acceleration space, and step 15 is executed;

[0049] when When the time is right, determine whether equation (14) is true. If it is true, it means that the j-th car has enough room to accelerate and execute step 15; otherwise, execute step 17.

[0050]

[0051] Step 15: Apply acceleration control to the j-th vehicle;

[0052] Step 15.1: Calculate the acceleration of the j-th vehicle to the maximum speed limit v of the road according to formula (15). max The shortest time required

[0053]

[0054] In equation (15), a max This indicates the maximum acceleration of a connected and autonomous vehicle.

[0055] Step 15.2: Determine whether equation (16) is true. If it is true, it means that the j-th vehicle has sufficient time to accelerate to the maximum speed limit v of the road. max If yes, proceed to step 15.3; otherwise, proceed to step 15.5.

[0056]

[0057] Step 15.3: Determine whether equation (17) is true. If it is true, it means that the j-th vehicle has accelerated to the maximum speed limit v of the road. max During the process, if there is no conflict with the (j-1)th vehicle, proceed to step 15.4; otherwise, proceed to step 15.5.

[0058]

[0059] Step 15.4: Calculate the acceleration of the j-th vehicle to the maximum speed limit v of the road according to formula (18). max acceleration a at time j-up-max Then, the j-th car with a j-up-max Accelerate until the emergency vehicle that needs to make a U-turn merges into the second lane, and then proceed to step 16;

[0060]

[0061] In equation (18), T j-up-max This indicates that the j-th vehicle accelerates to the road's maximum speed limit v. max The time taken;

[0062] Step 15.5: Calculate the value of vehicle j during the control period [t0, t0+T] according to equation (19). 总 The acceleration a passing through the turning point j-up ;

[0063]

[0064] Step 15.6: Calculate the j-th vehicle using equations (20) and (21) respectively. The x-coordinate of the front position of the vehicle at any time t2 and the x-coordinate of the front position of the (j-1)th vehicle at any time t2. Therefore, we can determine whether equation (22) holds true. If it does, it means that there is no conflict between the j-th car and the (j-1)-th car during the acceleration process, and the j-th car accelerates at a... j-up Accelerate through the U-turn point until the emergency vehicle that needs to make a U-turn merges into the second lane, and then proceed to step 16; otherwise, proceed to step 17.

[0065]

[0066]

[0067]

[0068] In equations (20)-(22),

[0069] Step 16: Perform control on the (j+1)th vehicle;

[0070] Step 16.1: Determine whether the vehicle number of the (j+1)th vehicle is in set I. If it is, proceed to step 16.2; otherwise, the (j+1)th vehicle continues to travel in the state at time t0 until the emergency vehicle that needs to turn around turns around and merges into the second lane, and the process ends.

[0071] Step 16.2: Calculate the acceleration a of the (j+1)th vehicle according to equation (23). j+1 Then, according to a j+1 Deceleration control is applied to the (j+1)th vehicle until the emergency vehicle that needs to make a U-turn merges into the second lane, and the process ends.

[0072]

[0073] In equation (23), Let x represent the x-coordinate of the position of the (j+1)th vehicle at time t0; This represents the speed of the (j+1)th vehicle at time t0;

[0074] Step 17: Calculate the acceleration a of the j-th vehicle according to equation (24). j-down Then, according to a j-down Deceleration control is applied to vehicle j until the emergency vehicle that needs to make a U-turn merges into the second lane, and the process ends.

[0075]

[0076] 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 cooperative control method, and the processor is configured to execute the program stored in the memory.

[0077] The present invention discloses a computer-readable storage medium on which a computer program is stored, wherein the computer program is executed by a processor to perform the steps of the cooperative control method.

[0078] Compared with existing technologies, the beneficial technical effects of this invention are reflected in:

[0079] 1. This invention operates within a vehicle-to-everything (V2X) environment, enabling vehicles to more accurately perceive their surroundings, identify their location, determine whether they meet control conditions, and conduct intelligent information exchange and 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.

[0080] 2. This invention can predict the vehicle status during the future control period based on the real-time driving status of oncoming vehicles, and implement different control strategies for vehicles accordingly, which greatly improves the operating efficiency of vehicles on U-turn sections and avoids traffic conflicts. Attached Figure Description

[0081] Figure 1 This is the overall flowchart of the present invention;

[0082] Figure 2 This is a decision-making flowchart for the present invention;

[0083] Figure 3 This is a schematic diagram of a scenario according to the present invention. Detailed Implementation

[0084] In this embodiment, an emergency vehicle U-turn collaborative control method in a connected environment is applied to a two-way four-lane U-turn section. A one-way U-turn lane is set up in the median strip of the U-turn section. All vehicles in this connected environment are connected autonomous vehicles. Emergency vehicles needing to make a U-turn have priority. When an emergency vehicle needs to make a U-turn, vehicles in the pre-U-turn area must yield to the emergency vehicle. The method controls the acceleration and deceleration of vehicles in the inner lane to obtain a safe insertion gap, providing space for the emergency vehicle to make the U-turn. Specifically, as follows... Figure 1 and Figure 2 As shown, the method includes the following steps:

[0085] Step 1, as follows Figure 3 As shown, in a two-way four-lane U-turn section, the lanes traveling in the same direction as the emergency vehicle needing to make a U-turn are numbered sequentially from the inside out as the third lane and the fourth lane, while the lanes traveling in the opposite direction to the emergency vehicle are numbered sequentially from the outside in as the first lane and the second lane. The center point of the one-way U-turn lane is taken as the U-turn point for the emergency vehicle, the U-turn point is taken as the origin x0, the direction of travel of the emergency vehicle is taken as the positive x-axis, and the direction perpendicular to the x-axis is taken as the y-axis, thus establishing a road coordinate system.

[0086] To ensure that emergency vehicles can safely decelerate to their maximum U-turn speed within the pre-U-turn area, the length L needs to be calculated. On the third lane, starting from the origin x0, the length L is calculated using the x-coordinate... l The road area enclosed by the endpoint is used as the pre-turn-around area for emergency vehicles, and the length L of the pre-turn-around area is determined using equation (1):

[0087]

[0088] In equation (1), v max Indicates the maximum speed limit on the road; v ev-turn-max Indicates the maximum safe U-turn speed for emergency vehicles; a ev-down-max This indicates the maximum safe deceleration of the emergency vehicle.

[0089] On the second lane, starting from the origin x0, with the x-coordinate x m The road area enclosed by the endpoint is designated as the oncoming vehicle control area, and the length M of the oncoming vehicle control area is determined using equation (2):

[0090]

[0091] In equation (2), a down-max This indicates the maximum safe deceleration of a connected autonomous vehicle.

[0092] Step 2, as follows Figure 3 As shown, at time t, all vehicles on the expressway are connected autonomous vehicles. Based on vehicle type, there are two types: emergency vehicles and ordinary vehicles. Emergency vehicles are also connected autonomous vehicles, but their body length and other characteristics differ from ordinary CAVs. They are all equipped with onboard perception systems that can sense changes in the surrounding traffic environment. Roadside intelligent transportation equipment collects vehicle information in the second and third lanes at time t, including: vehicle type, number of vehicles, vehicle length, vehicle position, speed, and acceleration. In this embodiment, the roadside intelligent transportation equipment is evenly distributed on both sides of the road and interacts with the CAVs in real time via wireless network communication.

[0093] Step 3: Determine if there is an emergency vehicle that needs to make a U-turn in the third lane. If there is, proceed to step 4; otherwise, assign t+Δt to t and return to step 2 to execute sequentially, where Δt is the time update step size. If there is an emergency vehicle that needs to make a U-turn in the third lane, ensure that there are no emergency vehicles in the oncoming vehicle control area to guarantee the priority of the emergency vehicle that needs to make a U-turn in the third lane.

[0094] Step 4: Determine whether equation (3) is true. If it is true, it means that the emergency vehicle that needs to make a U-turn arrives at the pre-U-turn area at time t0 and reaches the maximum speed limit v of the road. max If the emergency vehicle that needs to make a U-turn arrives at the pre-U-turn area at time t0 but does not reach the maximum speed limit v of the road, then proceed with step 5.1. Otherwise, it indicates that the emergency vehicle that needs to make a U-turn arrived at the pre-U-turn area at time t0 but did not reach the maximum speed limit v of the road. max Then proceed to step 5.2;

[0095]

[0096] In equation (3), This indicates the speed of the emergency vehicle that needs to make a U-turn when it arrives at the pre-U-turn area at time t0.

[0097] Step 5: Calculate the time T required for the emergency vehicle that needs to make a U-turn to reach the U-turn point and merge into the second lane. 总 ;

[0098] Step 5.1: Emergency vehicles that need to turn around should decelerate at the maximum safe speed a. ev-down-max The vehicle slows down and travels to the origin x0, and the time T required for the emergency vehicle to reach the origin x0 is calculated according to equation (4). ev Then, proceed to step 5.4;

[0099]

[0100] Step 5.2: Calculate the maximum acceleration a of the emergency vehicle that needs to turn around within the pre-turn-around area according to equation (5). ev-up-max The maximum intermediate speed v that can be achieved by acceleration ev-middle-max ;

[0101]

[0102] Step 5.3: Calculate the maximum acceleration a of the emergency vehicle that needs to turn around according to equation (6). ev-up-max First accelerate to the maximum intermediate speed v ev-middle-max Then decelerate at the maximum safe rate a ev-down-max The time T required to decelerate back to the origin x0 ev ;

[0103]

[0104] Step 5.4: Calculate the time T required for the emergency vehicle that needs to make a U-turn to travel from the pre-U-turn area to the origin x0 and then make a U-turn to merge into the second lane, according to formula (7). 总 ;

[0105] T 总 =T ev +T ev-turn-min (7)

[0106] In equation (7), T ev-turn-min This indicates the shortest time required for an emergency vehicle to make a U-turn and merge into the second lane. Generally, the value varies depending on the road alignment and the type of vehicle. However, since the U-turn lane is relatively short, the time required for a vehicle to make a U-turn and merge into the oncoming lane is also relatively short, and its proportion is small compared to the entire control period.

[0107] Step 6: Execute the oncoming vehicle cooperative control strategy. Number the vehicles in the oncoming vehicle control area at time t0 according to their distance from the origin x0, from closest to farthest, as 1, 2, ..., n; control time period [t0, t0+T] 总 Within the control area for oncoming vehicles, overtaking is not permitted.

[0108] Step 7: Iterate through each vehicle within the control area of ​​the opposing vehicle. For the i-th vehicle, i∈[1,n], determine whether equation (8) holds. If it holds, it indicates that the vehicle is within the control period [t0,t0+T]. 总 At the end of the period, if the i-th vehicle conflicts with an emergency vehicle that needs to turn around, the number of the conflicting vehicle is recorded in set I; if none of the conflicts occur, it indicates that the control period [t0, t0+T] is complete. 总 At the end of the process, there is no conflict between all vehicles in the oncoming vehicle control area and the emergency vehicle that needs to make a U-turn. All vehicles in the oncoming vehicle control area continue to drive according to the state at time t0 until the emergency vehicle that needs to make a U-turn merges into the second lane, and the process ends.

[0109]

[0110] In equation (8), Let x represent the x-coordinate of the position of the front of the i-th vehicle at time t0; Let l represent the velocity of the i-th vehicle at time t0; ev This indicates the body length of emergency vehicles; the body length of connected autonomous vehicles is consistent, with 'l' representing the body length of connected autonomous vehicles; L min This indicates the minimum safe following distance.

[0111] Step 8: Denote the vehicle with the smallest number value in set I as the j-th vehicle;

[0112] Step 9: Determine whether equation (9) is true. If it is not true, it means that the j-th vehicle did not reach the maximum speed limit v at time t0. max If the first conflicting vehicle has reached its maximum speed limit, it cannot accelerate further and can only decelerate. If it has not reached its maximum speed limit, we need to determine whether it has room to accelerate during the control period.

[0113]

[0114] In equation (9), Let represent the speed of the j-th vehicle at the initial control time t0.

[0115] Step 10: If j≥2, the first vehicle among the first j-1 vehicles in the opposing vehicle control area maintains its speed at time t0, and the remaining j-2 vehicles follow the first vehicle and form a convoy according to the CACC following model shown in equation (10), and then proceed to step 11; otherwise, proceed to step 17; when the j-th vehicle has not reached the maximum speed limit, we form a convoy for all the vehicles in front of it according to the minimum safe following distance to make enough space for it to accelerate; when j=2, there is only one vehicle in front of it, which acts as the first vehicle and maintains a constant speed, and the number of subsequent vehicles is 0, and the convoy time is... =0;

[0116]

[0117] In equation (10), Δx w Let w represent the headway between any w-th vehicle among the first j-1 vehicles and the vehicle in front of it at time t1, where w > 1 and t1 ∈ [t0, t0 + T]. 总 ]; e w Indicate Δx w The difference between the expected front-end spacing and the desired front-end spacing; t c The desired headway; v w,prew Let k be the speed of vehicle w at time t1 before time t1; p k is the control parameter for the difference in frontage distance. d The differential control parameter for the difference in frontage distance; v w This represents the speed of the w-th vehicle.

[0118] Step 11: Calculate the x-coordinate of the head position of the (j-1)th vehicle after formation according to formula (11).

[0119]

[0120] In equation (11), The x-coordinate represents the position of the front of the first vehicle within the control area of ​​the opposing vehicle at time t0; This represents the speed of the first vehicle within the control area of ​​the oncoming vehicle at time t0; This represents the time required for the first j-1 vehicles in the opposing vehicle control area to complete the formation; once the parameters of the CACC model are calibrated, we can obtain the time required for vehicle formation.

[0121] Step 12: Calculate the x-coordinate of the head position of the j-th car after the first j-1 cars are convoyed according to formula (12).

[0122]

[0123] In equation (12), Let x represent the x-coordinate of the position of the j-th vehicle's front end at time t0.

[0124] Step 13: Determine whether equation (13) is true. If it is true, it means that after the first j-1 cars are grouped together, the jth car will not conflict with it, and proceed to step 14; otherwise, proceed to step 17.

[0125]

[0126] Step 14: Determine whether the j-th vehicle has sufficient acceleration space;

[0127] when At that time, the j-th vehicle has sufficient acceleration space, and step 15 is executed;

[0128] when When the time is right, determine whether equation (14) is true. If it is true, it means that the j-th car has enough acceleration space and execute step 15; otherwise, execute step 17.

[0129]

[0130] Step 15: Apply acceleration control to the j-th vehicle.

[0131] Step 15.1: Calculate the acceleration of the j-th vehicle to the maximum speed limit v of the road according to formula (15). max The shortest time required

[0132]

[0133] In equation (15), a max This indicates the maximum acceleration of a connected and autonomous vehicle.

[0134] Step 15.2: Determine whether equation (16) is true. If it is true, it means that the j-th vehicle has sufficient time to accelerate to the maximum speed limit v of the road. max If the j-th vehicle does not have enough time to accelerate to the maximum speed limit, then execute step 15.3; otherwise, execute step 15.5; if the j-th vehicle does not have enough time to accelerate to the maximum speed limit, then still execute acceleration control on it, but it will not accelerate to the maximum speed limit.

[0135]

[0136] Step 15.3: Determine whether equation (17) is true. If it is true, it means that the j-th vehicle has accelerated to the maximum speed limit v of the road. max During the process, if there is no conflict with the (j-1)th vehicle, proceed to step 15.4; otherwise, proceed to step 15.5. When the jth vehicle is accelerating to the maximum speed limit and there is a conflict with the vehicle in front, still perform acceleration control on it, but accelerate to the maximum speed limit, while ensuring that it does not conflict with the vehicle in front.

[0137]

[0138] Step 15.4: Calculate the acceleration of the j-th vehicle to the maximum speed limit v of the road according to formula (18). max acceleration a at time j-up-max Then, the j-th car with a j-up-max Accelerate until the emergency vehicle that needs to make a U-turn merges into the second lane, and then proceed to step 16; the j-th vehicle first accelerates to the maximum speed limit of the road, and then drives at a constant speed. The time for driving at a constant speed here may be 0, because driving at a constant speed after accelerating to the maximum speed limit may cause a conflict with the vehicle in front, depending on the situation.

[0139]

[0140] In equation (18), T j-up-max This indicates that the j-th vehicle accelerates to the road's maximum speed limit v. max The time taken.

[0141] Step 15.5: Calculate the value of vehicle j during the control period [t0, t0+T] according to equation (19). 总 The acceleration a passing through the turning point j-up ;

[0142]

[0143] Step 15.6: Based on equations (20) and (21), determine whether equation (22) holds true. If it holds true, it indicates that the j-th vehicle does not conflict with the (j-1)-th vehicle during acceleration, and the j-th vehicle accelerates at a... j-up Accelerate through the U-turn point until the emergency vehicle that needs to make a U-turn merges into the second lane, and then proceed to step 16; otherwise, proceed to step 17.

[0144]

[0145]

[0146]

[0147] In equations (20)-(22), Let x and y represent the x-coordinates of the front positions of the j-th and (j-1)-th vehicles at any time t2, respectively.

[0148] Step 16: Perform control on the (j+1)th vehicle;

[0149] Step 16.1: Determine whether the vehicle number of the (j+1)th vehicle is in set I. If it is, proceed to step 16.2; otherwise, the (j+1)th vehicle continues to travel in the state at time t0 until the emergency vehicle that needs to turn around turns around and merges into the second lane, and the process ends.

[0150] Step 16.2: Calculate the acceleration a of the (j+1)th vehicle according to equation (23). j+1 Then, according to a j+1 Deceleration control is applied to the (j+1)th vehicle until the emergency vehicle that needs to make a U-turn merges into the second lane, and the process ends.

[0151]

[0152] In equation (23), Let x represent the x-coordinate of the position of the (j+1)th vehicle at time t0; Let represent the speed of the (j+1)th vehicle at time t0.

[0153] Step 17: Calculate the acceleration a of the j-th vehicle according to equation (24). j-down Then, according to a j-down Deceleration control is applied to vehicle j until the emergency vehicle that needs to make a U-turn merges into the second lane, and the process ends.

[0154]

[0155] In this embodiment, an electronic device includes a memory and a processor. The memory is used to store a program that supports the processor in executing the above-described cooperative control method, and the processor is configured to execute the program stored in the memory.

[0156] In this embodiment, a computer-readable storage medium is provided, on which a computer program is stored, and the computer program is executed by a processor to perform the steps of the above-described cooperative control method.

Claims

1. A collaborative control method for emergency vehicle U-turns in a networked environment, characterized in that, This method is applied to U-turn sections with four lanes in both directions. A one-way U-turn lane is set up in the median strip of the U-turn section. The vehicles in the connected environment are all connected autonomous vehicles. The U-turn cooperative control method includes the following steps: Step 1: In a two-way four-lane U-turn section, the lanes traveling in the same direction as the emergency vehicle needing to make a U-turn are numbered sequentially from the inside out as the third lane and the fourth lane, and the lanes traveling in the opposite direction to the emergency vehicle are numbered sequentially from the outside in as the first lane and the second lane; the center point of the one-way U-turn lane is the U-turn point of the emergency vehicle, the U-turn point is the origin x0, the direction of travel of the emergency vehicle is the positive x-axis, and the direction perpendicular to the x-axis is the y-axis, to establish a road coordinate system; On the third lane, starting from the origin x0, with the x-coordinate x l The road area enclosed by the endpoint is used as the pre-turn-around area for emergency vehicles, and the length L of the pre-turn-around area is determined using equation (1): In equation (1), v max Indicates the maximum speed limit on the road; v ev-turn-max This indicates the maximum safe U-turn speed of the emergency vehicle; a ev-down-max This indicates the maximum safe deceleration of the emergency vehicle; On the second lane, starting from the origin x0, with the x-coordinate x m The road area enclosed by the endpoint is designated as the oncoming vehicle control area, and the length M of the oncoming vehicle control area is determined using equation (2): In equation (2), a down-max This indicates the maximum safe deceleration of a connected autonomous vehicle; Step 2: Use roadside intelligent transportation equipment to collect vehicle information in the second and third lanes at time t, including: vehicle type, number of vehicles, vehicle length, vehicle position, speed, and acceleration; Step 3: Determine if there is an emergency vehicle that needs to make a U-turn in the third lane. If there is, proceed to step 4; otherwise, assign t+Δt to t and return to step 2 to execute sequentially, where Δt is the time update step size. Step 4: Determine whether equation (3) is true. If it is true, it means that the emergency vehicle that needs to make a U-turn arrives at the pre-U-turn area at time t0 and reaches the maximum speed limit v of the road. max If the emergency vehicle that needs to make a U-turn arrives at the pre-U-turn area at time t0 but does not reach the maximum speed limit v of the road, then proceed with step 5.

1. Otherwise, it indicates that the emergency vehicle that needs to make a U-turn arrived at the pre-U-turn area at time t0 but did not reach the maximum speed limit v of the road. max Then proceed to step 5.2; In equation (3), This indicates the speed of the emergency vehicle that needs to make a U-turn when it arrives at the pre-U-turn area at time t0; Step 5: Calculate the time T required for the emergency vehicle that needs to make a U-turn to reach the U-turn point and merge into the second lane. 总 ; Step 5.1: Emergency vehicles that need to turn around should decelerate at the maximum safe speed a. ev-down-max The vehicle slows down and travels to the origin x0, and the time T required for the emergency vehicle to reach the origin x0 is calculated according to equation (4). ev Then, proceed to step 5.4; Step 5.2: Calculate the maximum acceleration a of the emergency vehicle that needs to turn around within the pre-turn-around area according to equation (5). ev-up-max The maximum intermediate speed v that can be achieved by acceleration ev-middle-max ; Step 5.3: Calculate the maximum acceleration a of the emergency vehicle that needs to turn around according to equation (6). ev-up-max First accelerate to the maximum intermediate speed v ev-middle-max Then decelerate at the maximum safe rate a ev-down-max The time T required to decelerate back to the origin x0 ev ; Step 5.4: Calculate the time T required for the emergency vehicle that needs to make a U-turn to travel from the pre-U-turn area to the origin x0 and then make a U-turn to merge into the second lane, according to formula (7). 总 ; T 总 =T ev +T ev-turn-min (7) In equation (7), T ev-turn-min This indicates the shortest time required for an emergency vehicle to make a U-turn and merge into the second lane. Step 6: Execute the oncoming vehicle cooperative control strategy. Number the vehicles in the oncoming vehicle control area at time t0 in order of distance from the front of the vehicle to the origin x0, from closest to farthest, as 1, 2, ..., n. Step 7: Iterate through each vehicle within the control area of ​​the opposing vehicle. For the i-th vehicle, i∈[1,n], determine whether equation (8) holds. If it holds, it indicates that the vehicle is within the control period [t0,t0+T]. 总 At the end of the period, if the i-th vehicle conflicts with an emergency vehicle that needs to turn around, the number of the conflicting vehicle is recorded in set I; if none of the conflicts occur, it indicates that the control period [t0, t0+T] is complete. 总 At the end of the process, there is no conflict between all vehicles in the oncoming vehicle control area and the emergency vehicle that needs to make a U-turn. All vehicles in the oncoming vehicle control area continue to drive according to the state at time t0 until the emergency vehicle that needs to make a U-turn merges into the second lane, and the process ends. In equation (8), Let x represent the x-coordinate of the position of the front of the i-th vehicle at time t0; Let l represent the velocity of the i-th vehicle at time t0; ev The symbol 'l' represents the body length of the emergency vehicle; 'l' represents the body length of the connected autonomous vehicle; L min Indicates the minimum safe following distance; Step 8: Denote the vehicle with the smallest number value in set I as the j-th vehicle; Step 9: Determine whether equation (9) is true. If it is not true, it means that the j-th vehicle did not reach the maximum speed limit v at time t0. max If yes, proceed to step 10; otherwise, proceed to step 17. In equation (9), This represents the speed of the j-th vehicle at the initial control time t0; Step 10: If j≥2, the first vehicle in the first j-1 vehicles in the opposing vehicle control area maintains the speed at time t0 and drives at a constant speed. The remaining j-2 vehicles follow the first vehicle and form a platoon according to the CACC car-following model shown in equation (10), and then execute step 11; otherwise, execute step 17. In equation (10), Δx w Let w represent the headway between any w-th vehicle among the first j-1 vehicles and the vehicle in front of it at time t1, where w > 1 and t1 ∈ [t0, t0 + T]. 总 ]; e w Indicate Δx w The difference between the expected front-end spacing and the desired front-end spacing; t c The desired headway; v w,prew Let k be the speed of vehicle w at time t1 before time t1; p k is the control parameter for the difference in frontage distance. d The differential control parameter for the difference in frontage distance; v w This represents the speed of the w-th vehicle; Step 11: Calculate the x-coordinate of the head position of the (j-1)th vehicle after formation according to formula (11). In equation (11), The x-coordinate represents the position of the front of the first vehicle within the control area of ​​the opposing vehicle at time t0; This represents the speed of the first vehicle within the control area of ​​the oncoming vehicle at time t0; This indicates the time required for the first j-1 vehicles in the opposing vehicle control area to complete their formation; Step 12: Calculate the x-coordinate of the head position of the j-th car after the first j-1 cars are convoyed according to formula (12). In equation (12), The x-coordinate represents the position of the j-th vehicle's front end at time t0; Step 13: Determine whether equation (13) is true. If it is true, it means that after the first j-1 cars are grouped together, the jth car will not conflict with it, and proceed to step 14; otherwise, proceed to step 17. Step 14: Determine whether the j-th vehicle has sufficient acceleration space; when When this occurs, it indicates that the j-th vehicle has sufficient acceleration space, and step 15 is executed; when When the time is right, determine whether equation (14) is true. If it is true, it means that the j-th car has enough room to accelerate and execute step 15; otherwise, execute step 17. Step 15: Apply acceleration control to the j-th vehicle; Step 15.1: Calculate the acceleration of the j-th vehicle to the maximum speed limit v of the road according to formula (15). max The shortest time required In equation (15), a max This indicates the maximum acceleration of a connected and autonomous vehicle. Step 15.2: Determine whether equation (16) is true. If it is true, it means that the j-th vehicle has sufficient time to accelerate to the maximum speed limit v of the road. max If yes, proceed to step 15.3; otherwise, proceed to step 15.

5. Step 15.3: Determine whether equation (17) is true. If it is true, it means that the j-th vehicle has accelerated to the maximum speed limit v of the road. max During the process, if there is no conflict with the (j-1)th vehicle, proceed to step 15.4; otherwise, proceed to step 15.

5. Step 15.4: Calculate the acceleration of the j-th vehicle to the maximum speed limit v of the road according to formula (18). max acceleration a at time j-up-max Then, the j-th car with a j-up-max Accelerate until the emergency vehicle that needs to make a U-turn merges into the second lane, and then proceed to step 16; In equation (18), T j-up-max This indicates that the j-th vehicle accelerates to the road's maximum speed limit v. max The time taken; Step 15.5: Calculate the value of vehicle j during the control period [t0, t0+T] according to equation (19). 总 The acceleration a passing through the turning point j-up ; Step 15.6: Calculate the j-th vehicle using equations (20) and (21) respectively. The x-coordinate of the front position of the vehicle at any time t2 and the x-coordinate of the front position of the (j-1)th vehicle at any time t2. Therefore, we can determine whether equation (22) holds true. If it does, it means that there is no conflict between the j-th car and the (j-1)-th car during the acceleration process, and the j-th car accelerates at a... j-up Accelerate through the U-turn point until the emergency vehicle that needs to make a U-turn merges into the second lane, and then proceed to step 16; otherwise, proceed to step 17. In equations (20)-(22), Step 16: Perform control on the (j+1)th vehicle; Step 16.1: Determine whether the vehicle number of the (j+1)th vehicle is in set I. If it is, proceed to step 16.2; otherwise, the (j+1)th vehicle continues to travel in the state at time t0 until the emergency vehicle that needs to turn around turns around and merges into the second lane, and the process ends. Step 16.2: Calculate the acceleration a of the (j+1)th vehicle according to equation (23). j+1 Then, according to a j+1 Deceleration control is applied to the (j+1)th vehicle until the emergency vehicle that needs to make a U-turn merges into the second lane, and the process ends. In equation (23), Let x represent the x-coordinate of the position of the (j+1)th vehicle at time t0; This represents the speed of the (j+1)th vehicle at time t0; Step 17: Calculate the acceleration a of the j-th vehicle according to equation (24). j-down Then, according to a j-down Deceleration control is applied to vehicle j until the emergency vehicle that needs to make a U-turn merges into the second lane, and the process ends.

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 cooperative control method of 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, The computer program is executed by the processor to perform the steps of the cooperative control method of claim 1.

Images