Emergency vehicle control method based on intersection dynamic lane in intelligent network connection environment

Abstract

The invention relates to an emergency vehicle control method based on an intersection dynamic lane in an intelligent network connection environment, and belongs to the field of emergency traffic control. The method comprises two parts of macroscopic planning and microcosmic control. According to the macroscopic planning part, an optimal path from an emergency vehicle to an accident point is planned through an A * algorithm, and a traffic organization method of each intersection is determined. According to the micro control part, an intersection is divided into a normal driving area, a buffer area and a conflict area through the vehicle-road cooperation technology, a road side control unit is used for planning a special lane for emergency vehicles, then other vehicles in the special lane are regulated and controlled to change lanes and enter a variable regulation and control lane, and finally the passing phases of the special lane and the variable regulation and control lane are controlled. And the emergency vehicle can be ensured to rapidly pass at a high speed per hour when driving into the buffer area. According to the method, the efficiency and the safety of emergency traffic are effectively improved by accurately controlling the intelligent signal lamp and combining the lane queue length and passing phase calculation.

Description

Technical Field

[0001] The present invention belongs to the field of emergency traffic control and management, and relates to an emergency vehicle control method based on dynamic lanes at intersections in an intelligent network environment. Background Art

[0002] In modern urban traffic management, with the surge in vehicle ownership and the continuous increase in traffic flow, traditional traffic control systems are facing unprecedented challenges. Problems such as traffic congestion, delayed accident response, and environmental pollution are becoming increasingly prominent, and a more intelligent and efficient traffic management solution is urgently needed. The rise of intelligent and connected vehicle (ICV) technology provides a new opportunity to solve these problems. By integrating advanced information and communication technology, data processing technology, and automated control technology, the intelligent connected system can achieve efficient communication between vehicles (V2V) and vehicles and infrastructure (V2I), thereby improving the overall operating efficiency and safety of the transportation system.

[0003] In the intelligent connected environment, the complexity of traffic management is further increased, especially the handling of mixed traffic flows of connected and automated vehicles (CAV) and human-driven vehicles (HDV). With its high degree of automation and intelligence, CAV can achieve better driving efficiency and safety in traffic flow, while HDV brings additional challenges to traffic management due to the subjectivity and uncertainty of its drivers. Especially in emergency situations, such as the rapid passage of emergency vehicles such as ambulances and fire trucks, due to factors such as traffic congestion, inadequate implementation of priority rights, insufficient technical support, long driver reaction time, and insufficient regulations and education, emergency vehicles often find it difficult to reach their destination quickly, which seriously affects emergency response efficiency and traffic safety. Therefore, how to effectively coordinate and manage this mixed traffic flow while ensuring traffic safety has become a key issue in the design of intelligent transportation systems. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide an emergency vehicle control method based on dynamic lanes at intersections in an intelligent network environment, which improves the traffic efficiency of urban intersections through V2I collaborative communication control technology and provides convenience for emergency traffic time saving.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] An emergency vehicle control method based on dynamic lanes at intersections in an intelligent network environment includes two parts: macro planning and micro control.

[0007] The macro planning part includes:

[0008] S1. Based on the location of the emergency event and the location of the emergency vehicle, the road intersection is taken as the road network node to generate the urban road network; the location where the emergency event occurs should be equipped with a traffic cloud control platform, and the emergency vehicle is an intelligent connected car with V2X communication and autonomous driving functions;

[0009] S2. Based on the generated urban road network, the A* algorithm is used to plan the global optimal path from the starting point (the location of the emergency vehicle) to the end point (the location of the emergency event), and the travel direction of each intersection road network node is given; the traffic cloud control platform sends the global optimal path information to the micro-control part, and then realizes the control of each intersection communication through the roadside control unit.

[0010] The micro-control part includes:

[0011] S3. Divide the roads in the intersection area into normal driving area, buffer zone and conflict zone; and each intersection is equipped with multiple road side units (RSU), road side sensing equipment, road side computing units (MEC) and intelligent traffic lights. In the normal driving area, emergency vehicles, CAVs and HDVs all drive normally and are not affected; in the buffer zone, vehicles are not allowed to change lanes freely, CAVs and HDVs can be controlled by the road side control unit to change lanes, accelerate, decelerate and other operations, and HDVs are uncertain under the guidance of the intelligent traffic lights controlled by the road side control unit, and there are two situations: obeying the control and changing lanes; in the conflict zone: emergency vehicles maintain a constant speed and drive along the current road, and HDVs drive normally;

[0012] S4. The roadside control unit plans a dedicated lane for the emergency vehicle according to the traffic direction of the intersection given by the macro-planning part. When the emergency vehicle enters the buffer zone of the dedicated lane, it determines whether to adjust the intelligent connected vehicles and manually driven vehicles in the dedicated lane to change lanes into the variable control lane according to the status of the current traffic lights in the dedicated lane. At the same time, the roadside control unit calculates the traffic phase duration of the dedicated lane and the variable control lane and the red and green traffic phase control duration of the intelligent traffic lights to coordinate the traffic light duration of other lanes in the intersection, so that the emergency vehicle can pass through the intersection at a uniform speed and efficiently.

[0013] Furthermore, in step S2, using the A* algorithm to generate the global optimal path includes:

[0014] The A* algorithm mainly consists of three parts: heuristic function h(n), cost function g(n), and total evaluation function f(n). The heuristic function h(n) represents the estimated cost from node n to the target; the cost function g(n) represents the actual path cost from the starting point to any node n; and the total evaluation function f(n) represents the total cost estimate of node n. The formulas of the three are:

[0015] Heuristic function h(n): Let the starting point be (x,y) and the end point be (x g ,y g ), then the heuristic function is the Euclidean distance between two points:

[0016]

[0017] Cost function g(n): represents the congestion cost of each intersection node. When moving to the node, the cost value of the node is obtained and accumulated:

[0018] g(n)=g(n)+n

[0019] Total evaluation function f(n): Combine the heuristic function and the cost function to get the total cost of the node to decide which nodes should be given priority:

[0020] f(n)=g(n)+h(n)

[0021] The current congestion level of each intersection node is taken to represent the cost of the node. The higher the congestion level, the higher the cost, and the lower the congestion level, the lower the cost. By calculating the cost of each point, and finally backtracking each node according to the starting point and the end point, a global optimal path is generated.

[0022] Furthermore, in step S4, at each intersection, according to the traffic direction of each intersection planned by the global optimal path, the corresponding lane in the intersection is designated as a dedicated lane for emergency vehicles, and the emergency vehicle passes through the intersection along the dedicated lane. The variable control lane is an adjacent lane to the dedicated lane. The variable control lane has the function of passing the original lane and the function of passing the dedicated lane, that is, if the original lane is a left-turn lane and the dedicated lane is a straight lane, then after the original lane becomes a variable control lane, it can go straight or turn left.

[0023] Furthermore, when an emergency vehicle enters the buffer zone of a dedicated lane, if the current traffic light in the dedicated lane is green, there is no need to control the smart connected vehicles and manually driven vehicles in the dedicated lane to change lanes into the variable control lane. Otherwise, the smart connected vehicles and manually driven vehicles in the dedicated lane are controlled to change lanes into the variable control lane.

[0024] Furthermore, when an emergency vehicle enters the buffer zone of a dedicated lane and the current traffic light in the dedicated lane is green, there is no need to control the intelligent connected vehicles and manually driven vehicles in the dedicated lane to change lanes and enter the variable control lane; at the same time, the roadside control unit calculates the time required for the emergency vehicle to reach the intersection, controls the current green light duration of the dedicated lane to extend the time, and coordinates to control the red light duration of lanes in other directions of the intersection to extend the time, so that the emergency vehicle can pass through the intersection at a uniform and efficient speed.

[0025] Furthermore, when the emergency vehicle enters the buffer zone of the dedicated lane, and the current signal light of the dedicated lane is not in the green light state, the intelligent networked vehicles and manually driven vehicles in the dedicated lane are regulated to change lanes and enter the variable regulated lane. It is determined whether all manually driven vehicles obey the regulation to change lanes and enter the variable regulated lane. The number of manually driven vehicles in the dedicated lane is recorded by the roadside control unit, and the traffic phase duration of the dedicated lane and the variable regulated lane and the red and green traffic phase regulation duration of the intelligent signal light are calculated to coordinate the signal light duration of other directional lanes at the intersection, so that the emergency vehicle can pass through the intersection at a uniform speed and efficiently.

[0026] The details are as follows:

[0027] 1) If all manually driven vehicles obey the control and change lanes to enter the variable control lane, the number of vehicles in the dedicated lane is 0. The roadside control unit calculates the time required for the emergency vehicle to reach the intersection at a constant speed, and also calculates the traffic phase duration of the dedicated lane and the variable control lane, as well as the red and green traffic phase control duration of the intelligent traffic light.

[0028] Among them, the time required for the emergency vehicle to reach the intersection at a constant speed is t c for:

[0029]

[0030] Where x is the distance between the emergency vehicle and the intersection, v c represents the speed of the emergency vehicle. Since there are no other vehicles in the dedicated lane, t c As the duration of the traffic phase of the dedicated lane. The duration of the traffic phase of the variable control lane t sp for:

[0031]

[0032] Where M sp represents the number of vehicles in the variable control lane, s f Indicates the distance traveled by the front vehicle when the rear vehicle starts, a n Indicates the vehicle starting acceleration, L n Indicates the vehicle body length, ΔS * Indicates the safety distance, v erepresents the expected speed, s l Indicates the distance the vehicle needs to travel from starting to accelerating to the desired speed.

[0033] After calculating the duration of the dedicated lane and the variable control lane, the original green light phase duration of the other lanes at the intersection is shortened to t g ′, and reserve the yellow light phase duration t y ; At the same time, take t c and t sp The larger one is used as the duration t of the red light phase extension of other lanes r , t r =max[t c ,t sp ]; then the green light phase duration of the dedicated lane and the variable control lane is t g =t r -t y ; Among them, when the emergency vehicle enters the buffer zone for time t g ′+t y After that, the dedicated lane and the variable control lane are simultaneously changed to the green light traffic state.

[0034] 2) If some manually driven vehicles obey the control and change lanes to enter the variable control lane, there is a manually driven vehicle in the dedicated lane. The roadside control unit calculates the time required for the emergency vehicle to reach the intersection at a constant speed, and simultaneously calculates the traffic phase duration of the dedicated lane and the variable control lane, as well as the red and green traffic phase control duration of the intelligent traffic light; among which, the traffic phase duration of the dedicated lane includes the traffic phase duration of the manually driven vehicle and the traffic phase duration of the emergency vehicle.

[0035] The time t required for an emergency vehicle to reach the intersection at a constant speed c for:

[0036]

[0037] The duration of the traffic phase of manually driven vehicles in the dedicated lane is t sp 'for:

[0038]

[0039] In the formula, M′ represents the number of manually driven vehicles in the dedicated lane. Then the duration of the traffic phase of the dedicated lane is t c +t sp ′.

[0040] The duration of the traffic phase of the variable control lane t sp for:

[0041]

[0042] Among them, M lp Indicates the number of vehicles in the variable control lane.

[0043] After calculating the duration of the dedicated lane and the variable control lane, the original green light phase duration of the other lanes at the intersection is shortened to t g ′, and reserve the yellow light phase duration t y ; At the same time, take t c +t sp ′ and t sp The larger of the two is used as the duration t of the red light phase extension of the other lanes. r , t r =max[t c +t sp ′,t sp ]; then the green light phase duration of the dedicated lane and the variable control lane is t g =t r -t y ; Among them, when the emergency vehicle enters the buffer zone for time t g ′+t y After that, the dedicated lane and the variable control lane are simultaneously changed to the green light traffic state.

[0044] The beneficial effects of the present invention are as follows: the present invention uses the A* algorithm to perform macroscopic path planning, so that the system can quickly plan the optimal path to ensure that the emergency vehicle reaches the destination at the fastest speed. At the same time, by setting up dedicated lanes and variable control lanes and microscopic control of lane phase regulation, the waiting time of emergency vehicles at intersections is effectively reduced, and traffic efficiency is improved. In addition, by dividing the intersection scene into different areas and implementing coordinated control, the present invention ensures the orderliness of vehicle travel, reduces the risk of conflicts and accidents, and thus significantly improves the efficiency and success rate of emergency response.

[0045] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

[0047] Figure 1 It is a schematic diagram of the process of the method of the present invention;

[0048] Figure 2 This is a schematic diagram of the urban road network;

[0049] Figure 3 This is a schematic diagram of the urban road network path;

[0050] Figure 4 This is a schematic diagram of the intersection scene;

[0051] Figure 5 This is a schematic diagram of the dedicated lane at the intersection;

[0052] Figure 6 It is a schematic diagram of the trajectory of HDV obeying the control phase;

[0053] Figure 7 Schematic diagram of the trajectory of HDV that does not obey the control phase. DETAILED DESCRIPTION

[0054] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0055] This embodiment is based on the following premises:

[0056] (1) The intersection scenario is a typical six-lane intersection in both directions, equipped with RSU, MEC, roadside sensing equipment, and intelligent traffic lights. The roadside sensing equipment detects and counts the number of vehicles on the lane in real time.

[0057] (2) The emergency event is concretely defined as a fire in a residential area at location A, and location B is the fire station closest to the residential area, such as Figure 2 As shown, the emergency vehicle fire truck is a CAV.

[0058] (3) This embodiment considers two situations: a. The HDV obeys the control of the roadside cooperative control unit. When the roadside cooperative control unit controls the vehicle to change lanes, both the CAV and the HDV can be controlled to change lanes to the variable control lane, clearing the dedicated lane; b. The HDV does not obey the control of the roadside cooperative control unit. When the roadside cooperative control unit controls the vehicle to change lanes, only the CAV can be controlled to change lanes, and the HDV does not obey the control. This situation is more in line with the current situation of HDV.

[0059] (4) In this embodiment, the specific details of the lane change are not considered when regulating the vehicle's lane change. By default, when a lane change is required, the vehicle can complete the lane change immediately.

[0060] like Figure 1The figure shows an emergency vehicle control method based on dynamic lanes at intersections in an intelligent network environment provided by this embodiment. The method includes two parts: macro planning and micro control.

[0061] The macro planning part includes:

[0062] Step S1: According to the occurrence of a fire emergency, point A is a community where the fire occurs, point B is the fire station closest to the community, point A is the end point, point B is the starting point, and the urban road intersections within the range are taken as nodes to generate an urban road network, such as Figure 2 As shown;

[0063] Step S2: Based on the generated urban road network, the A* algorithm is used to plan the global optimal path from the starting point to the end point, and the travel direction of each intersection road network node is given;

[0064] Step S21: Based on the urban road network generated in step S1, the A* algorithm is used to plan the global optimal path, wherein the A* algorithm is a heuristic search algorithm for finding the shortest path from the starting point to the end point in the graph. The algorithm mainly includes three main functions: cost function g(n), heuristic function h(n) and total evaluation function f(n) to evaluate the quality of the path;

[0065] Step S22: Generate the global optimal path information according to step S21, which includes the driving direction at each intersection, that is, how to pass (straight, left turn, right turn); the emergency vehicle sends the global optimal path information to the traffic cloud control platform, and the traffic cloud control platform sends the global optimal path information to the micro-control part, and then realizes the control of the dedicated lanes at each intersection through the roadside control unit.

[0066] The specific operations of step S21 are as follows:

[0067] The A* algorithm mainly consists of three parts, where the heuristic function h(n) represents the estimated cost from node n to the target; the cost function g(n) represents the actual path cost from the starting point to any node n; and the total evaluation function f(n) represents the total cost estimate of node n. The formulas are:

[0068] Heuristic function h(n): Let the starting point be (x,y) and the end point be (x g ,y g ), then the heuristic function is the Euclidean distance between two points:

[0069]

[0070] Cost function g(n): represents the congestion cost of each intersection node. When moving to the node, the cost value of the node is obtained and accumulated:

[0071] g(n)=g(n)+n

[0072] Total evaluation function f(n): Combine the heuristic function and the cost function to get the total cost of the node to decide which nodes should be given priority:

[0073] f(n)=g(n)+h(n)

[0074] In this embodiment, the starting point is point A0 and the end point is point E4. The current congestion level of each intersection node is taken to represent the cost of the node. The higher the congestion level, the higher the cost, and the lower the congestion level, the lower the cost. By calculating the cost of each point, each node is backtracked according to the starting point and the end point to generate a global optimal path (A0, B0, C0, D0, D1, D2, D3, E3, E4). The global optimal path is as follows: Figure 3 shown.

[0075] The micro-control part includes:

[0076] Step S3: using a vehicle-road collaboration-based intersection collaborative control method to divide the intersection scene into regions, namely, a normal driving area, a buffer area, and a conflict area;

[0077] Step S31: The overall intersection scene is divided into a normal driving area, a buffer area, and a conflict area. Each intersection is equipped with multiple roadside units (RSUs), roadside sensing devices, roadside computing units (MECs), and intelligent traffic lights, such as Figure 4 As shown;

[0078] Step S32: In the normal driving area, emergency vehicles, CAVs and HDVs all drive normally and are not affected; in the buffer zone, vehicles are not allowed to change lanes freely, and CAVs and HDVs can be controlled by the roadside cooperative control unit to change lanes, accelerate, decelerate and other operations. HDVs are uncertain under the guidance of the intelligent traffic lights controlled by the roadside cooperative control unit, and there are two situations: obeying the control and changing lanes; in the conflict zone: emergency vehicles maintain a constant speed and drive along the current road, and HDVs drive normally;

[0079] The specific operations of step S4 are as follows:

[0080] Step S41: According to the path planning route given by the macro planning part, a dedicated lane is designated for each intersection. For example, if the current intersection keeps going straight, the middle lane is set as a dedicated lane for going straight;

[0081] Step S42, set the road section with a length of 130m before the intersection as a buffer zone, the area before the buffer zone is a free driving zone, vehicles are not allowed to change lanes freely in the buffer zone, and the roadside equipment records the number of vehicles in the buffer zone in real time; consider the emergency vehicle fire truck entering the buffer zone in advance according to the traffic flow, count the number of vehicles in front of the emergency vehicle fire truck, if the current lane is already in the green light phase, proceed to step S44 to calculate the extended travel phase time; if the current lane is not in the green light phase, proceed to the next step S43;

[0082] Step S43: The driving lanes and the buffer zones of each intersection planned by the global path are defined as special lanes, and the lanes adjacent to the special lanes are defined as variable control lanes. The variable control lanes have the functions of the original lanes and the special lanes, that is, the direction of the original lanes can be changed to be the same as the direction of the special lanes. For example, if the current intersection needs to keep going straight, there is a special lane for going straight, and the adjacent left-turn lane or right-turn lane can be defined as a variable control lane. The left lane of the special lane is taken as the variable control lane. The special lanes at the intersection are as follows: Figure 5 When the emergency fire truck is about to enter the dedicated lane buffer, the roadside cooperative control unit controls the CAV and HDV in the dedicated lane to change lanes into the variable control lane. The intelligent signal light controls the straight-through dedicated lane and the variable control lane as the highest priority, and shortens the travel phase of other direction lanes in advance, reserves sufficient intersection space for the dedicated lane, and calculates the travel phase of the dedicated lane;

[0083] Step S44: The roadside control unit calculates the time required for the emergency vehicle fire truck to maintain the current speed and pass through the intersection at a constant speed based on the position and speed of the emergency vehicle fire truck. There are two situations:

[0084] 1) All HDVs obey the control and change lanes to enter the variable control lane. The current dedicated lane is completely empty. The roadside cooperative control unit also needs to calculate the phase passage time of the variable control lane and the red and green phase control time of the intelligent traffic light P(t g ′,t I ,t g ), and then follow the dedicated lane to implement single-port release to relieve the traffic pressure at the current intersection; among them, t g ′ represents the remaining time after the phase in other directions is shortened, t I Indicates the time that the red light phase in other directions needs to be extended, t g Indicates the green light duration of dedicated lanes and variable control lanes;

[0085] 2) Some HDVs do not obey the lane change control. There are still some HDVs in front of the current dedicated lane. The roadside cooperative control unit needs to calculate the traffic phase of the current dedicated lane and the variable control lane, as well as the red and green traffic phase control duration P(tg ′,t I ,t g ), and sends control signals to intelligent traffic lights to coordinate and adjust the duration of traffic lights in other lanes to ensure that emergency vehicles pass through the intersection at a uniform and efficient speed.

[0086] Among them, the passing phase P(t g ′,t I ,t g ) is calculated as follows:

[0087] First, calculate the duration of the passing phase, the formula is as follows:

[0088]

[0089] Where, t p represents the duration of the traffic phase (s), M represents the number of vehicles in the current lane, s f Indicates the distance traveled by the front vehicle when the rear vehicle starts (m), a n Indicates the vehicle starting acceleration (m / s 2 ), L n Indicates the vehicle body length (m), ΔS * Indicates the safety distance (m), v e represents the expected speed (m / s), s l Indicates the distance (m) that the vehicle needs to travel from starting to accelerating to the desired speed.

[0090] Secondly, most intersections are low-speed urban roads, so the GIPPS model is selected as the vehicle following model, which is expressed as:

[0091]

[0092] In the formula, v l is the speed of the preceding vehicle (m / s), s is the distance between the following vehicle and the preceding vehicle (m), v safe represents the safety speed constraint function, b is the deceleration braking constant, Δt is the reaction time constant, and s0 represents the minimum distance (m) from the front vehicle when the front vehicle suddenly decelerates to a stop.

[0093] Based on the above formula, the duration of the through lane and the variable control lane is calculated. Consider the situation that the current lane is in the red light phase and the emergency vehicle fire truck is about to enter the through lane buffer. For the convenience of calculation, the time dimension of the vehicle is described in relative time, with the unit of s, the spatial distance unit of m, and the speed unit of m / s. Assuming that the intersection length is d = 27.6m, the emergency vehicle fire truck travels at a speed v in the city. c =14m / s≈50km / h. The specific parameter settings during the control process are shown in Table 1:

[0094] Table 1

[0095]

[0096] Specifically, for case 1), all HDVs obey the control and change lanes to enter the variable control lanes, and the travel time of the dedicated lanes and the variable control lanes needs to be calculated. Among them, the travel time of the dedicated lane is the time t required for the emergency vehicle fire truck to maintain the current speed and reach the intersection at a constant speed. c Calculated by the following formula:

[0097]

[0098] The duration of the variable control lane is as follows: the number of straight vehicles entering the east entrance is 6, and the number of left-turning vehicles entering the east entrance is 4, according to the roadside sensing equipment. The number of vehicles changing lanes and entering the variable control lane is 6, and the duration of the variable control lane phase is:

[0099]

[0100] Since the above formula in this example except M sp All other variables are constants, so the above formula can be simplified to:

[0101] t sp =(M sp -1)×2.4125-0.7

[0102] Among them, M sp is the number of vehicles in the variable control lane, M sp =6+4=10, we get t sp ≈21s.

[0103] After obtaining the passing phase time, the roadside control unit adjusts the intelligent traffic lights, and the original green light phase duration in the west, south and north is shortened to t g ′=3s, reserve the yellow light phase t y =3s, red light phase extension t r =t sp = 21s; after the emergency vehicle fire truck enters the buffer zone t g ′+t y = 6s, open the green light phase of the dedicated lane and the variable control lane, implement single-port release, and the green light phase duration is t g =t r -t y = 18s, allowing straight vehicles that change lanes into the variable control lane to pass completely, reducing the impact on the original traffic order, such as Figure 6 shown.

[0104] For case 2), the HDV does not obey the control lane change, then the number of vehicles in the dedicated lane is 2, and the number of vehicles in the variable control lane is 8. The traffic phase of the dedicated lane and the variable control lane needs to be calculated. Among them, the time t required for the emergency vehicle to arrive at the intersection c for:

[0105]

[0106] The duration of the HDV traffic phase in the dedicated lane is:

[0107]

[0108] Since all the above equations except M' are constants in this example, they can be simplified to:

[0109] t sp ′=(M′-1)×2.4125-0.7

[0110] Where M′ is the number of HDVs ahead of the emergency vehicle in the dedicated lane, M′=2, and we get t sp ′≈2s.

[0111] The duration of the variable control lane is as follows: the number of left-turning vehicles at the east entrance is 4, and the number of CAVs changing lanes in the dedicated lane is 4. The number of vehicles in the variable control lane is 8, and the duration of the pass phase is:

[0112]

[0113] Since in the above formula, except for M lp All other variables are constants, so the above formula can be simplified to:

[0114] t lp =(M lp -1)×2.4125-0.7

[0115] Among them, M lp is the number of vehicles in the variable control lane, M lp =4+4=8, we get t lp ≈17s.

[0116] After obtaining the passing phase time, the roadside control unit adjusts the intelligent traffic lights, and the original green light phase duration in the west, south and north is shortened to t g ′=3s, reserve the yellow light phase t y =3s, red light phase extension t r =t lp = 17s; after the emergency vehicle fire truck enters the buffer zone t g ′+t y= 6s, open the green light phase of the dedicated lane and the variable control lane, implement single-port release, and the green light phase duration is t g =t r -t y = 14s, allowing the straight-moving vehicles that change lanes into the variable control lane to pass completely, reducing the impact on the original traffic order, such as Figure 7 shown.

[0117] The above process takes into account the situation where the dedicated lane is in the red light phase. When the emergency vehicle fire truck enters the buffer zone, the dedicated lane has already been green. The duration of the dedicated lane passage phase and the red-green passage phase control duration of the intelligent signal light are calculated. When the dedicated lane has been green, there is no need to control other vehicles in the dedicated lane buffer zone to change lanes. The green light passage duration of the dedicated lane is directly extended, and the red light duration of other directional lanes is correspondingly extended. Specifically, the time t required for the emergency vehicle fire truck to maintain the current uniform speed to reach the intersection is calculated. c :

[0118]

[0119] Then, the green light phase duration of the dedicated lane needs to be extended by 9s, and the red light phase duration of other directional lanes needs to be extended by 9s.

[0120] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. An emergency vehicle control method based on dynamic lanes at intersections in an intelligent network environment, characterized in that: The location of the emergency event is taken as the end point, the location of the emergency vehicle is taken as the starting point, and the urban road intersections are taken as nodes to construct an urban road network; wherein the emergency vehicle is an intelligent network-connected vehicle; According to the generated urban road network, the A* algorithm is used to plan the global optimal path for the emergency vehicle to reach the emergency event location, and the travel direction of each intersection passed by the path is given; At each intersection, according to the traffic direction of each intersection planned by the global optimal path, the corresponding lane in the intersection is designated as a dedicated lane for emergency vehicles, and the emergency vehicle passes through the intersection along the dedicated lane; at the same time, the lane adjacent to the dedicated lane is defined as a variable control lane for the vehicle in front of the emergency vehicle to change lanes; wherein the vehicles in the intersection area include intelligent network-connected vehicles and manually driven vehicles; The intersection road is divided into a normal driving area, a buffer area and a conflict area; in the buffer area, vehicles are not allowed to change lanes freely, and in the conflict area, emergency vehicles maintain a constant speed and travel in the planned direction; When the emergency vehicle enters the buffer zone of the dedicated lane, it is determined whether to regulate the intelligent connected vehicles and manually driven vehicles in the dedicated lane to change lanes and enter the variable control lane according to the status of the current traffic lights in the dedicated lane. At the same time, the roadside control unit calculates the traffic phase duration of the dedicated lane and the variable control lane and the red and green traffic phase regulation duration of the intelligent traffic lights to coordinate the traffic light duration of other lanes in the intersection, so that the emergency vehicle can pass through the intersection at a uniform speed and efficiently.

2. The emergency vehicle control method according to claim 1, characterized in that: When the emergency vehicle enters the buffer zone of the dedicated lane, if the current traffic light of the dedicated lane is green, there is no need to control the intelligent connected vehicles and manually driven vehicles in the dedicated lane to change lanes and enter the variable control lane; otherwise, the intelligent connected vehicles and manually driven vehicles in the dedicated lane are controlled to change lanes and enter the variable control lane.

3. The emergency vehicle control method according to claim 1 or 2, characterized in that: When an emergency vehicle enters the buffer zone of a dedicated lane and the current traffic light in the dedicated lane is green, there is no need to control the smart connected vehicles and manually driven vehicles in the dedicated lane to change lanes and enter the variable control lane; at the same time, the roadside control unit calculates the time required for the emergency vehicle to reach the intersection, controls the current green light duration of the dedicated lane to extend the time, and coordinates to control the red light duration of lanes in other directions of the intersection to extend the time, so that the emergency vehicle can pass through the intersection at a uniform and efficient speed.

4. The emergency vehicle control method according to claim 1 or 2, characterized in that: When an emergency vehicle enters the buffer zone of a dedicated lane and the current traffic light in the dedicated lane is not green, the intelligent connected vehicles and manually driven vehicles in the dedicated lane are regulated to change lanes and enter the variable regulated lane; It is determined whether all the manually driven vehicles obey the control and change lanes to enter the variable control lane. The number of manually driven vehicles in the dedicated lane is recorded by the roadside control unit. The traffic phase duration of the dedicated lane and the variable control lane and the red and green traffic phase control duration of the intelligent traffic light are calculated to coordinate the signal light duration of other lanes in the intersection, so that emergency vehicles can pass through the intersection at a uniform speed and efficiently.

5. The emergency vehicle control method according to claim 4, characterized in that: When all manually driven vehicles obey the control and change lanes to enter the variable control lane, the number of vehicles in the dedicated lane is 0, and the roadside control unit calculates the time t required for the emergency vehicle to reach the intersection at a constant speed. c : Where x is the distance between the emergency vehicle and the intersection, v c represents the speed of the emergency vehicle; since there are no other vehicles in the dedicated lane, t c as the duration of the traffic phase of the dedicated lane; Calculate the duration t of the variable control lane sp : Where M sp Represents the number of vehicles in the variable control lane, s f Indicates the distance traveled by the front vehicle when the rear vehicle starts, a n Indicates the vehicle starting acceleration, L n Indicates the body length, ΔS * Indicates the safety distance, v e represents the expected speed, s l Indicates the distance the vehicle needs to travel from starting to accelerating to the desired speed; After calculating the duration of the dedicated lane and the variable control lane, the original green light phase duration of the other lanes at the intersection is shortened to t g ′, and reserve the yellow light phase duration t y ; At the same time, take t c and t sp The larger one is used as the duration t of the red light phase extension of other lanes r , t r =max[t c ,t sp ′]; then the green light phase duration of the dedicated lane and the variable control lane is t g =t r -t y ; Among them, when the emergency vehicle enters the buffer zone for time t g ′+t y After that, the dedicated lane and the variable control lane are simultaneously changed to the green light traffic state.

6. The emergency vehicle control method according to claim 4, characterized in that: When some manually driven vehicles obey the control and change lanes to enter the variable control lane, there are manually driven vehicles in the dedicated lane. The roadside control unit calculates the time t required for the emergency vehicle to reach the intersection at a constant speed. c : Where x is the distance between the emergency vehicle and the intersection, v c Indicates the emergency vehicle speed; Calculate the duration t of the passing phase of manually driven vehicles in the dedicated lane sp ′: Where M′ represents the number of manually driven vehicles ahead of the emergency vehicle in the dedicated lane, s f Indicates the distance traveled by the front vehicle when the rear vehicle starts, a n Indicates the vehicle starting acceleration, L n Indicates the body length, ΔS * Indicates the safety distance, v e represents the expected speed, s l Indicates the distance the vehicle needs to travel from starting to accelerating to the desired speed; The duration of the dedicated lane's traffic phase is t c +t sp ′; Calculate the duration t of the variable control lane sp : Where M lp Indicates the number of vehicles in the variable control lane; After calculating the duration of the dedicated lane and the variable control lane, the original green light phase duration of the other lanes at the intersection is shortened to t g ′, and reserve the yellow light phase duration t y ; At the same time, take t c +t sp ′ and t sp The larger one is used as the duration t of the red light phase extension of other lanes r , t r =max[t c +t sp ′,t sp ]; then the green light phase duration of the dedicated lane and the variable control lane is t g =t r -t y ; Among them, when the emergency vehicle enters the buffer zone for time t g ′+t y After that, the dedicated lane and the variable control lane are simultaneously changed to the green light traffic state.

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