Urban road emergency lane dynamic emptying method based on intelligent network connection technology

Abstract

The invention provides an urban road emergency lane dynamic emptying method based on an intelligent network connection technology, and belongs to the field of intelligent traffic control. The method comprises the following steps of: firstly, acquiring basic information of urban roads, state information of vehicles on an emptying road section, the total number of non-emergency vehicles and the speed of an aggregation wave of a lane in front of the emergency vehicles, and discretizing the emptying road section; then, a dynamic emptying road section range is determined, an upper-layer model with the purpose of minimizing the total lane changing cost of the non-emergency vehicle is established based on steering information of the non-emergency vehicle, and an improved A * algorithm is adopted to calculate the shortest time-consuming lane changing track of the non-emergency vehicle; and finally, based on the lane changing cost of the non-emergency vehicle, establishing a lower-layer model with the goal of minimizing the influence on the emergency vehicle, and calculating an emptying inspiration point to realize dynamic emptying of the urban road emergency lane. The method considers the predicted steering of the vehicle, reduces the delay of the non-emergency vehicle at the intersection and the influence on the normal driving of the emergency vehicle, and improves the passing efficiency of the emergency vehicle.

Description

Technical Field

[0001] The present application belongs to the field of intelligent traffic control, and in particular, relates to a method for dynamically clearing emergency lanes on urban roads based on intelligent network connection technology. Background Art

[0002] As society continues to develop, the problem of vehicle congestion has become increasingly serious. Especially in emergency situations, emergency vehicles (such as ambulances, fire trucks, police cars, etc.) often face serious obstacles to passage. Traditional traffic management methods lack sufficient flexibility and intelligence, which makes it difficult for emergency vehicles to arrive at the scene of accidents or emergencies in a timely manner, greatly affecting the realization of their priority right of way. Technical methods for priority control of emergency vehicles can improve the efficiency of urban emergency rescue, alleviate overall traffic pressure, and provide strong support for improving the comprehensive management level of urban transportation systems.

[0003] Existing emergency vehicle priority methods mostly focus on signal priority control based on the time dimension, which provides green light phases for emergency vehicles at intersections by switching to pre-defined or adaptive signal control schemes. However, priority control that relies solely on the time dimension has limited effect in complex urban road environments. Due to the large traffic volume in cities, it is difficult for emergency vehicles to obtain priority on urban roads, which weakens the effectiveness of signal priority methods and leads to larger traffic delays.

[0004] Therefore, this application aims to optimize the priority passage of emergency vehicles in the spatial dimension, thereby reducing overall traffic delays. Current technical solutions usually set up dedicated emergency lanes or conduct manual traffic control, which rely on human intervention, have a low degree of automation, and are difficult to respond to emergencies in real time, affecting the traffic efficiency of emergency vehicles. The rapid development of intelligent network technology has provided new solutions and technical support for urban traffic management. Through vehicle networking technology, traffic conditions can be monitored in real time, the use of emergency lanes can be optimized, non-emergency vehicles can be coordinated, obstacles to emergency vehicles can be reduced, and their needs for rapid passage can be met in a more precise manner.

[0005] By searching the existing literature on the emergency vehicle priority issue, it is found that most of the existing literature focuses on the reservation of fixed lanes and the parking and avoidance of non-emergency vehicles, often ignoring the reasonable allocation of traffic resources. Some related studies on intelligent connected environments only focus on the priority of emergency vehicles, without taking into account the optimization of non-emergency vehicle lane change trajectories, or there are deficiencies in the optimization depth. In addition, although some studies can obtain the best clearing solution, the time complexity of the solution is high.

[0006] In this context, this application proposes a method for dynamic clearing of emergency lanes on urban roads based on intelligent network technology. This method first optimizes the lane change trajectory of non-emergency vehicles based on the position, speed, and expected turning information of the networked vehicles to reduce delays to non-emergency vehicles. Then, from the perspective of the emergency vehicles, it analyzes where to trigger the clearing of the emergency lane, prompting non-emergency vehicles to change lanes from the emergency lane to the adjacent lane to minimize the impact on the emergency vehicles. By triggering the clearing multiple times, the dynamic clearing of the emergency lane is achieved. This is the main problem solved by this application. Summary of the invention

[0007] In response to the deficiencies of existing research, the present application provides a method for dynamic clearing of emergency lanes on urban roads based on intelligent network technology. Taking into account the expected turning of non-emergency vehicles, a two-layer model is established. The upper layer plans the shortest lane change trajectory of non-emergency vehicles to minimize the total lane change cost, thereby reducing the impact on non-emergency vehicles. The lower layer calculates the clearing inspiration point with the least impact on emergency vehicles under the premise of satisfying the minimum total lane change cost of non-emergency vehicles, thereby realizing dynamic clearing of emergency lanes on urban roads, thereby improving the traffic efficiency of emergency vehicles and reducing vehicle delays at intersections.

[0008] The method for dynamically clearing emergency lanes on urban roads based on intelligent network connection technology provided in this application includes the following steps: Step 1: Input the basic information of urban roads, including the number of lanes, length and width of the cleared road section; input the status information of vehicles on the cleared road section, including the position of emergency vehicles, the speed of emergency vehicles, the position of non-emergency vehicles, the speed of non-emergency vehicles and the expected turn; input the total number of non-emergency vehicles; input the gathering wave speed of the lane in front of the emergency vehicle; discretize the cleared road section; Step 2: Determine the scope of the dynamically cleared road section; Step 3: Based on the predicted turning of non-emergency vehicles, an upper-level model for dynamic clearance of emergency lanes is established. The total lane change cost of non-emergency vehicles is minimized as the upper-level objective function, and the improved A* algorithm is used to solve the problem and calculate the shortest lane change trajectory of each non-emergency vehicle. Step 4: Taking the minimum impact of non-emergency vehicles on emergency vehicles as the lower-level objective function, considering the lane change cost constraint of non-emergency vehicles, calculate the clearing heuristic point; Step 5: Adopt the joint optimization method of the upper and lower objective functions. When the optimal values ​​of the lane change cost of non-emergency vehicles in the upper model and the impact on emergency vehicles in the lower model converge and no longer change, terminate the iteration, output the final solution, determine the lane change plan and clearing inspiration point of non-emergency vehicles, and complete the emergency lane clearing task.

[0009] In one possible implementation manner, the method for dynamically clearing an urban road emergency lane based on intelligent network connection technology provided in an embodiment of the present application, step 1 includes the following: Step 11: Use Indicates the number of lanes in the cleared section, using Indicates clearing the length of the road section, using Indicates lane width, using Indicates the lane number, ;use Indicates the location of the emergency vehicle, using represents the expected speed of the emergency vehicle, Indicates non-emergency vehicles location, use Indicates non-emergency vehicles speed, with Indicates non-emergency vehicles The expected turn of ,in , , Respectively indicate left turn, straight ahead, and right turn; represents the total number of vehicles that are not emergency vehicles, ;use Represents the gathering wave speed of the lane ahead of the emergency vehicle; discretizes the cleared road section.

[0010] In one possible implementation manner, the method for dynamically clearing an emergency lane on an urban road based on intelligent network connection technology provided in the embodiment of the present application, in step 2, determining the range of a dynamically cleared road section includes the following steps: Step 21: Based on the discretization process in step 1, the vehicle travel direction is Axis, with lane distribution direction as A rectangular coordinate system consisting of several grid cells of the same size is established on the cleared road section. The position of each grid cell is determined by its horizontal coordinate. and the vertical coordinate Determine; the position of the grid cell where the emergency vehicle is located is the position of the grid cell where the non-emergency vehicle is ; The position of any vehicle in the cleared section is, and the constraints are as shown in formulas (1)-(2): (1) (2) In the above formula, is the grid length, is the grid width; Step 22: After the rectangular coordinate system is established, the road section to be cleared is mapped in the coordinate system. The dynamic clearing range is divided into two cases. If there are no queued vehicles within the dynamic clearing range, the length and width of the dynamic clearing area are the segment lengths of the clearing section. , Lane width , the starting position of the dynamic clearing area is , then the dynamic clearing section range is defined as shown in formulas (3)-(4): (3) (4) If there are queued vehicles within the dynamic clearing range, the width of the dynamic clearing area remains unchanged, and the lateral range of the dynamic clearing section is defined as shown in formula (5): (5) In the above formula, is the length of the dynamic clearing area, and the calculation method is shown in formula (6): (6) In the above formula, is the length of the immutable road segment, To estimate the queue length upstream of the intersection at the moment; according to the gathering wave speed of the lane ahead of the emergency vehicle and vehicle status information, The calculation method is shown in formula (7): (7) In the above formula, is the horizontal coordinate of the last connected vehicle stopped in the non-emergency vehicle queue, To estimate the time, The stopping time of the last connected vehicle in the non-emergency vehicle queue.

[0011] In one possible implementation, the method for dynamic clearing of emergency lanes on urban roads based on intelligent network connection technology provided in the embodiment of the present application, in the step 3, based on the predicted turning of non-emergency vehicles, an upper-level model for dynamic clearing of emergency lanes is established, and the total lane change cost of non-emergency vehicles is minimized as the upper-level objective function, and an improved A* algorithm is used for solving, and the shortest lane change trajectory of each non-emergency vehicle is calculated, including the following steps: Step 31: Non-emergency vehicles on the emergency lane of urban roads Leave the emergency lane by moving or changing lanes; during the clearing process, non-emergency vehicles must avoid conflicts, as shown in formulas (8)-(10): (8) (9) (10) In formulas (8) and (9), is the number of iterations, is the duration of the iteration steps, is the maximum number of iterations, For non-emergency vehicles In the The horizontal coordinate of the step position, For non-emergency vehicles In the The vertical coordinate of the step position, For non-emergency vehicles In the The lateral speed of the step, For non-emergency vehicles In the The longitudinal speed of the step, For non-emergency vehicles The horizontal coordinate of the position at step +1, For non-emergency vehicles The horizontal coordinate of the position at step +1, For non-emergency vehicles In the The position of the step, For non-emergency vehicles In the The position of the step; Step 32: The emergency vehicle always drives in the emergency lane and its speed needs to maintain the expected speed unchanged, as shown in formulas (11)-(13): (11) (12) (13) In formula (11), For emergency vehicles The vertical coordinate of the step position, is the initial position ordinate of the emergency vehicle. In formula (12), For emergency vehicles The horizontal coordinate of the step position, For emergency vehicles The horizontal coordinate of the step position, For emergency vehicles The speed of the step, in formula (13), is the speed of the emergency vehicle at the initial position; Step 33: Ensure vehicle safety during dynamic clearing and limit the distance between the emergency vehicle and the nearest non-emergency vehicle ahead Not less than the buffer length , as shown in formulas (14)-(16): (14) (15) (16) In formula (14), For the The horizontal coordinate of the non-emergency vehicle closest to the emergency vehicle on the emergency lane; Step 34: When the emergency vehicle reaches the clearing inspiration point, the non-emergency vehicles on the emergency lane begin to leave the emergency lane to ensure a safe distance between vehicles; at the initial moment of clearing, the distance between the emergency vehicle and the nearest non-emergency vehicle in front is Should not be less than the buffer length , as shown in formulas (17)-(18): (17) (18) In formulas (17) and (18), is the initial position horizontal coordinate of the non-emergency vehicle closest to the emergency vehicle on the emergency lane, is the initial position abscissa of the emergency vehicle, The optimal value of is to clear the heuristic point ; Step 35: When the connected vehicles are about to enter the dynamically cleared road section, left-turning vehicles select the left-turn lane, straight-moving vehicles select the straight-moving lane, and right-turning vehicles select the rightmost lane; non-emergency vehicles expected to turn left only move and change lanes in the left-turn lane, non-emergency vehicles expected to go straight only move and change lanes in the straight-moving lane, and non-emergency vehicles expected to turn right only move in the right-turn lane, as shown in formulas (19)-(28): (19) (20) (twenty one) (twenty two) (twenty three) (twenty four) (25) (26) (27) (28) In the above formula, is a binary variable, Indicates non-emergency vehicles The ordinate of the initial position is equal to the lane number, otherwise ; For non-emergency vehicles The initial position ordinate of A positive integer greater than or equal to 9999; Step 36: Calculate the time it takes for non-emergency vehicles to reach the clearing target location , as shown in formulas (29)-(31): (29) (30) (31) In formula (29), For non-emergency vehicles The horizontal coordinate when reaching the clearing target position, For non-emergency vehicles The initial position abscissa, For non-emergency vehicles The vertical coordinate when reaching the clearing target position, and For non-emergency vehicles The time it takes for the vehicle to move forward and change lanes to the adjacent lane during the process of reaching the cleared target position; Step 37: When there are no non-emergency vehicles on the emergency lane, the emergency lane of the road section is cleared, as shown in formula (32): (32) In formula (32), The vertical coordinate of the emergency vehicle when the emergency lane is cleared; Step 38: Calculate the time it takes for all non-emergency vehicles that need to leave the emergency lane to reach the clearing target position, and combine the unit cost of the emergency state during the clearing process to form the total lane change cost of non-emergency vehicles. The minimum total lane change cost is used as the upper objective function, as shown in formula (33): (33) In formula (33), is the unit time cost during the duration of the emergency state when the emergency lane is dynamically cleared, is the total lane change cost of non-emergency vehicles, is the minimum total cost of lane change for non-emergency vehicles, and the objective function is the time it takes for all non-emergency vehicles that need to leave the emergency lane to reach the cleared target position. The minimum value of the unit time cost in the process The product of , i.e., the total lane change cost of non-emergency vehicles, represents the impact on non-emergency vehicles; Step 39: Taking the minimum total lane change cost of non-emergency vehicles as the goal, calculate the mathematical model of formula (33), and the shortest lane change trajectory of each non-emergency vehicle is recorded as , By non-emergency vehicle location Orderly composition; Step 310: Based on the principle of the shortest path, the initial positions of the non-emergency vehicles are matched with the unoccupied positions in the non-emergency lanes one by one to determine the starting position and the clearing target position of each non-emergency vehicle; Step 311: Use the improved A* algorithm to plan the path for each pair of starting position and clearing target position; in the emergency lane clearing task, non-emergency vehicles There are multiple feasible solutions for the lane change trajectory. If the entire map is traversed and searched, computing resources will be wasted on invalid paths. The improved A* algorithm is based on non-emergency vehicles. The current position and expected turn of non-emergency vehicles The left road section is considered as an obstacle, thereby further narrowing the feasible search range of the current position. In addition, the heuristic function of the A* algorithm is improved to estimate the time cost from the current position to the clearing target position; through these optimizations, the shortest time path between the starting position of the non-emergency vehicle and the clearing target position is calculated. ; Step 312: Calculate the shortest lane change trajectory of each non-emergency vehicle , calculated as follows: traversing the path , set the first step of the path to the current position, and the next step to the target position; if the target position is occupied by multiple non-emergency vehicles at the same time, the conflicting vehicles will return to the previous step of the current position and replan the path with this position as the new starting position; if the target position is not occupied by other vehicles at the same time, the target position will be switched to the current position, and the next step will be set to the new target position, and then it will be determined whether this position is occupied by multiple non-emergency vehicles at the same time; this process continues until all non-emergency vehicles have safely arrived at the cleared target position, and the emergency lane of the road section has been cleared; in this process, the positions of non-emergency vehicles are arranged in order, and the shortest lane change trajectory of each non-emergency vehicle can be obtained. .

[0012] In one possible implementation manner, the method for dynamically clearing an urban road emergency lane based on intelligent network connection technology provided in an embodiment of the present application, the operation steps of the improved A* algorithm in step 3 include the following: Step 1: Define the initial map data; Step 2: Check the map data. If there is no non-emergency vehicle in the emergency lane, the algorithm ends; otherwise, go to step 3; Step 3: Define the valuation function f to estimate the time cost from the starting position to the empty target position, define the time function g to represent the actual time cost from the starting position to the current position, and define the heuristic function h to estimate the time cost from the current position to the empty target position, f=g+h; define the time cost of each move of the non-emergency vehicle; step4: Create an open list open_list and a closed list close_list, and initialize them to empty lists; Step 5: Select the starting position of non-emergency vehicles and the clearing target position; put the starting position into the initial open_list as a point to be checked; Step 6: Calculate the f value of each node in the open_list; select the node with the smallest f value from the open_list and use it as the current node. If the clear target position appears in the open_list, the shortest time path has been found; otherwise, remove the current node from the open_list and save it to the close_list; Step 7: According to the current position and expected turn of the non-emergency vehicle, the left node of the current node is regarded as an obstacle, and the adjacent extended node of the current node is checked. If it is already in the close_list, it is skipped directly; if it is already in the open_list, the current g value is recalculated, and the current g value is compared with the previous g value. The smaller g value is selected and the f value is updated, and its parent node is updated at the same time; if it is neither in the open_list nor in the close_list, it is put into the open_list, and its parent node and f, g, and h values ​​are confirmed; go to step 6; Step 8: Execute steps 5-7 again until all non-emergency vehicles obtain the corresponding shortest time path from the starting position to the clearing target position; when all non-emergency vehicles reach the clearing target position, the algorithm ends.

[0013] In one possible implementation, the method for dynamically clearing emergency lanes on urban roads based on intelligent network connection technology provided in the embodiment of the present application, in step 4, takes the minimum impact of non-emergency vehicles on emergency vehicles as the lower layer objective function, considers the lane change cost constraint of non-emergency vehicles, and calculates the clearing inspiration point, including the following steps: Step 41: Take the impact of non-emergency vehicles on emergency vehicles as the minimum as the lower objective function, and ensure that emergency vehicles move at a constant speed. Driving towards the intersection, as shown in formulas (34)-(36), combined with formulas (8)-(33), the inspiration point that triggers the emergency lane to be cleared is calculated , thereby prompting non-emergency vehicles to leave the emergency lane: (34) (35) (36) In formulas (34), (35), and (36), is the relative speed between emergency vehicles and non-emergency vehicles, For non-emergency vehicles The lateral velocity, For the The total number of non-emergency vehicles on the emergency lane, The cumulative interference time of the non-emergency vehicle on the emergency vehicle is calculated based on the distance between the non-emergency vehicle and the emergency vehicle. and the impact of non-emergency vehicles on emergency vehicles The distance between the emergency vehicle and the nearest non-emergency vehicle in front is When , the emergency lane is cleared; in formula (36), is the impact of non-emergency vehicles on emergency vehicles. Under the premise of minimizing the total cost of non-emergency vehicles changing lanes, the optimization goal is to minimize the impact of non-emergency vehicles on emergency vehicles. The smaller the distance between the emergency vehicle and the nearest non-emergency vehicle in front, the less time it takes to clear the road section, the less cumulative interference time non-emergency vehicles have on emergency vehicles, and the smaller the impact of non-emergency vehicles on emergency vehicles. The minimum value of the impact of non-emergency vehicles on emergency vehicles is recorded as .

[0014] In one possible implementation, the method for dynamically clearing emergency lanes on urban roads based on intelligent network connection technology provided in the embodiment of the present application, in step 5, adopts a joint optimization method of the upper and lower layer objective functions, and when the lane change cost of the non-emergency vehicle of the upper layer model and the optimal value of the impact on the emergency vehicle of the lower layer model converge and no longer change, the iteration is terminated, the final solution is output, the lane change plan and the clearing inspiration point of the non-emergency vehicle are determined, and the emergency lane clearing task is completed, including the following steps: Step 51: Starting from the minimum lane change cost of non-emergency vehicles in the upper model, the shortest lane change trajectory of each non-emergency vehicle is obtained, and then the upper and lower models are gradually iterated by jointly optimizing. After each iteration, the changing trends of the upper lane change cost and the lower emergency vehicle impact are checked. If the optimal values ​​of the two converge and remain unchanged in multiple consecutive iterations, the iteration is terminated; Step 52: After the iteration is terminated, the optimal solutions of the current upper layer and the lower layer are output, and the lane change plan and clearing inspiration point of the non-emergency vehicle in each dynamic clearing area are determined, so as to complete the clearing of the entire emergency lane.

[0015] Beneficial effects: Compared with the prior art, the method for dynamically clearing the emergency lane of an urban road based on intelligent network connection technology provided by the present application has the following advantages: By constructing a two-level planning model, the traffic efficiency and safety of emergency vehicles are effectively improved. This application comprehensively considers the expected turns of non-emergency vehicles, takes minimizing the total lane change cost of non-emergency vehicles as the upper-level goal, and minimizes the impact of non-emergency vehicles on emergency vehicles as the lower-level goal, thereby guiding non-emergency vehicles to leave the emergency lane and reach the clear target position in the shortest time, thus reducing vehicle delays at intersections and minimizing the impact on the normal driving of emergency vehicles.

[0016] By using the predicted turning information in the intelligent network environment, the feasible search range of the existing algorithm is narrowed, and the waste of computing resources on the invalid lane change trajectory of non-emergency vehicles is reduced. At the same time, combined with urban traffic rules and intersection signal phase status, the scope of the dynamic clearing section is determined, and the shortest lane change plan and the best clearing inspiration point for non-emergency vehicles are calculated, so that the emergency lane can be cleared in sections as the emergency vehicle moves dynamically, ensuring that emergency vehicles have priority on complex urban roads. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0018] Figure 1 This is a flow chart of a method for dynamically clearing emergency lanes on urban roads based on intelligent network connection technology provided by this application; Figure 2 It is a schematic diagram of dynamic clearing of emergency lanes on urban roads in a method for dynamic clearing of emergency lanes on urban roads based on intelligent network connection technology provided by this application; Figure 3a This is a schematic diagram of the first staged clearing of the emergency lane; Figure 3b This is a schematic diagram of the second stage of clearing the emergency lane; Figure 3c This is a schematic diagram of the third stage of clearing the emergency lane. DETAILED DESCRIPTION

[0019] The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, but should not be understood as limiting the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0020] See also Figure 1 and Figure 2 The overall control logic of the method for dynamic clearing of emergency lanes on urban roads based on intelligent network technology provided by this application is: the status information of vehicles on the road section to be cleared is collected through intelligent network technology, and the cleared road section is discretized in combination with the basic information of the urban road. The scope of the dynamically cleared road section is determined based on urban traffic rules and the phase state of intersection signals. The emergency lane is dynamically cleared section by section in a segmented manner to solve the problem of priority passage of emergency vehicles in complex urban road environments. For the clearing of each section of the emergency lane, this application calculates the shortest time lane change trajectory of each non-emergency vehicle and the inspiration point for triggering the clearing of the emergency lane based on the expected turning information of non-emergency vehicles obtained by intelligent network technology, and forms a dynamic clearing plan for the emergency lane. The dynamic clearing plan is distributed to non-emergency vehicles and emergency vehicles through intelligent network technology to ensure that emergency vehicles pass through the corresponding road section safely and efficiently with minimal impact. The emergency vehicle arrives at the clearing inspiration point of each section of the emergency lane in turn, and finally completes the task of clearing the emergency lane.

[0021] In combination with the accompanying drawings and embodiments, the technical solution of this application is described in detail as follows: The method for dynamically clearing emergency lanes on urban roads based on intelligent network connection technology provided in this application includes the following steps: Step 1: Input the basic information of urban roads, including the number of lanes, length and width of the cleared section. Input the status information of vehicles on the cleared section, including the position of emergency vehicles, the speed of emergency vehicles, the position of non-emergency vehicles, the speed of non-emergency vehicles and the expected turn. Input the total number of non-emergency vehicles. Input the gathering wave speed of the lane ahead of the emergency vehicle. Discretize the cleared section. The specific steps are as follows: Step 11: Use Indicates the number of lanes in the cleared section, using Indicates clearing the length of the road section, using Indicates lane width, using Indicates the lane number, .use Indicates the location of the emergency vehicle, using represents the expected speed of the emergency vehicle, Indicates non-emergency vehicles location, use Indicates non-emergency vehicles speed, with Indicates non-emergency vehicles The expected turn of ,in , , They respectively indicate left turn, straight ahead and right turn. represents the total number of vehicles that are not emergency vehicles, .use Represents the gathering wave speed of the lane ahead of the emergency vehicle. Discretize the cleared road section.

[0022] In this example, the number of lanes in the cleared section of the urban road upstream of the intersection is 4, the length of the cleared section is 500m, and the lane width is 3.5m. The expected speed of the emergency vehicle is 20m / s. At a certain moment, the position, number and lane number of the non-emergency vehicle on the cleared section are as follows: Figure 3a to Figure 3c As shown, the expected turning of vehicles in lane 4 is left turn, the expected turning of vehicles in lane 3 is straight or left turn, the expected turning of vehicles in lane 2 is straight, the expected turning of vehicles in lane 1 is right turn, the driving speed of non-emergency vehicles is uniformly 10m / s; the gathering wave speed of the lane in front of the emergency vehicle is 1.5m / s; the cleared section is discretized.

[0023] Step 2: Determine the scope of the dynamic clearing section. The specific steps are as follows: Step 21: Based on the discretization process in step 1, the vehicle travel direction is Axis, with lane distribution direction as A rectangular coordinate system consisting of several grid cells of the same size is established on the cleared road section. The position of each grid cell is determined by its horizontal coordinate. and the vertical coordinate The location of the grid cell where the emergency vehicle is located is The location of the grid cell where the non-emergency vehicle is located is The position of any vehicle in the cleared section is , the constraints are as shown in formulas (1)-(2): (1) (2) In the above formula, is the grid length, is the grid width.

[0024] Step 22: After the rectangular coordinate system is established, the road section to be cleared is mapped in the coordinate system. The dynamic clearing range is divided into two cases. If there are no queued vehicles within the dynamic clearing range, the length and width of the dynamic clearing area are the segment lengths of the clearing section. , Lane width , the starting position of the dynamic clearing area is , then the dynamic clearing section range is defined as shown in formulas (3)-(4): (3) (4) If there are queued vehicles within the dynamic clearing range, the width of the dynamic clearing area remains unchanged, and the lateral range of the dynamic clearing section is defined as shown in formula (5): (5) In the above formula, is the length of the dynamic clearing area, and the calculation method is shown in formula (6): (6) In the above formula, is the length of the immutable road segment, To estimate the queue length upstream of the intersection at the moment. According to the gathering wave speed of the lane ahead of the emergency vehicle and vehicle status information, The calculation method is shown in formula (7): (7) In the above formula, is the horizontal coordinate of the last connected vehicle stopped in the non-emergency vehicle queue, To estimate the time, The stopping time of the last connected vehicle in the non-emergency vehicle queue.

[0025] Step 3: Based on the predicted turning of non-emergency vehicles, an upper-level model for dynamic clearance of emergency lanes is established. The upper-level objective function is to minimize the total lane change cost of non-emergency vehicles. The improved A* algorithm is used to solve the problem and calculate the shortest lane change trajectory of each non-emergency vehicle. The specific steps are as follows: Step 31: Non-emergency vehicles on the emergency lane of the urban road leave the emergency lane by moving or changing lanes. During the clearing process, non-emergency vehicles must avoid conflicts, as shown in formulas (8)-(10): (8) (9) (10) In formulas (8) and (9), is the number of iterations, is the duration of the iteration steps, is the maximum number of iterations, For non-emergency vehicles In the The horizontal coordinate of the step position, For non-emergency vehicles In the The vertical coordinate of the step position, For non-emergency vehicles In the The lateral speed of the step, For non-emergency vehicles In the The longitudinal velocity of the step is the horizontal coordinate of the position at the +1 step. For non-emergency vehicles In the The horizontal coordinate of the step position, For non-emergency vehicles In the The position of the step, For non-emergency vehicles In the The position of the step.

[0026] Step 32: The emergency vehicle always drives in the emergency lane and its speed needs to maintain the expected speed unchanged, as shown in formulas (11)-(13): (11) (12) (13) In formula (11), For emergency vehicles The vertical coordinate of the step position, is the initial position ordinate of the emergency vehicle. In formula (12), For emergency vehicles The horizontal coordinate of the step position, For emergency vehicles The horizontal coordinate of the step position, For emergency vehicles The speed of the step, in formula (13), is the speed of the emergency vehicle at its initial position.

[0027] Step 33: Ensure vehicle safety during dynamic clearing and limit the distance between the emergency vehicle and the nearest non-emergency vehicle ahead Not less than the buffer length , as shown in formulas (14)-(16): (14) (15) (16) In formula (14), For the The horizontal coordinate of the non-emergency vehicle closest to the emergency vehicle in the emergency lane.

[0028] Step 34: When the emergency vehicle reaches the clearing inspiration point, the non-emergency vehicles in the emergency lane begin to leave the emergency lane to ensure a safe distance between vehicles. At the initial moment of clearing, the distance between the emergency vehicle and the nearest non-emergency vehicle in front Should not be less than the buffer length , as shown in formulas (17)-(18): (17) (18) In formulas (17) and (18), is the initial position horizontal coordinate of the non-emergency vehicle closest to the emergency vehicle on the emergency lane, is the initial position abscissa of the emergency vehicle, The optimal value of is to clear the heuristic point .

[0029] Step 35: When the connected vehicle is about to enter the dynamically cleared road section, the left-turning vehicle selects the left-turn lane, the straight-moving vehicle selects the straight-moving lane, and the right-turning vehicle selects the rightmost lane. Non-emergency vehicles that are expected to turn left will only move and change lanes in the left-turn lane, non-emergency vehicles that are expected to go straight will only move and change lanes in the straight-moving lane, and non-emergency vehicles that are expected to turn right will only move in the right-turn lane, as shown in formulas (19)-(28): (19) (20) (twenty one) (twenty two) (twenty three) (twenty four) (25) (26) (27) (28) In the above formula, is a binary variable, Indicates non-emergency vehicles The ordinate of the initial position is equal to the lane number, otherwise . For non-emergency vehicles The initial position ordinate. A positive integer greater than or equal to 9999.

[0030] Step 36: Calculate Non-Emergency Vehicles Time to reach the emptying target location , as shown in formulas (29)-(31): (29) (30) (31) In formula (29), For non-emergency vehicles The horizontal coordinate when reaching the clearing target position, For non-emergency vehicles The initial position abscissa, For non-emergency vehicles The vertical coordinate when reaching the clearing target position, and For non-emergency vehicles The time it takes for the vehicle to move forward and change lanes to the adjacent lane during the process of reaching the cleared target position.

[0031] Step 37: When there are no non-emergency vehicles on the emergency lane, the emergency lane of the road section is cleared, as shown in formula (32): (32) In formula (32), The vertical coordinate of the emergency vehicle when the emergency lane is cleared.

[0032] Step 38: Calculate the time it takes for all non-emergency vehicles that need to leave the emergency lane to reach the clearing target position, and combine the unit cost of the emergency state during the clearing process to form the total lane change cost of non-emergency vehicles. The minimum total lane change cost is used as the upper objective function, as shown in formula (33): (33) In formula (33), is the unit time cost during the duration of the emergency state when the emergency lane is dynamically cleared, is the total lane change cost of non-emergency vehicles, is the minimum total cost of lane change for non-emergency vehicles, and the objective function is the time it takes for all non-emergency vehicles that need to leave the emergency lane to reach the cleared target position. The minimum value of the unit time cost in the process The product of , i.e., the total lane change cost of non-emergency vehicles, represents the impact on non-emergency vehicles.

[0033] Step 39: Taking the minimum total lane change cost of non-emergency vehicles as the goal, calculate the mathematical model of formula (33), and the shortest lane change trajectory of each non-emergency vehicle is recorded as , By non-emergency vehicle location Orderly composition.

[0034] Step 310: Based on the principle of the shortest path, the initial positions of the non-emergency vehicles are matched with the unoccupied positions in the non-emergency lanes one by one to determine the starting position and the clearing target position of each non-emergency vehicle.

[0035] Step 311: Use the improved A* algorithm to plan the path for each pair of starting position and clearing target position. There are multiple feasible solutions for the lane change trajectory. If the entire map is traversed and searched, computing resources will be wasted on invalid paths. The improved A* algorithm is based on non-emergency vehicles. The current position and expected turn of non-emergency vehicles The left road segment is considered as an obstacle, thereby further narrowing the feasible search range of the current position. In addition, the heuristic function of the A* algorithm is improved to estimate the time cost from the current position to the clearing target position. Through these optimizations, the shortest time path between the starting position of the non-emergency vehicle and the clearing target position is calculated. .

[0036] Step 312: Calculate the shortest lane change trajectory of each non-emergency vehicle , calculated as follows: traversing the path , set the first step of the path to the current position, and the next step to the target position. If the target position is occupied by multiple non-emergency vehicles at the same time, the conflicting vehicles will return to the previous step of the current position and replan the path with this position as the new starting position. If the target position is not occupied by other vehicles at the same time, the target position is switched to the current position, and the next step is set to the new target position, and then it is determined whether this position is occupied by multiple non-emergency vehicles at the same time. This process continues until all non-emergency vehicles have safely arrived at the cleared target position, and the emergency lane of the section is cleared. In this process, the positions of non-emergency vehicles are arranged in order, and the shortest lane change trajectory of each non-emergency vehicle can be obtained. .

[0037] The operation steps of the improved A* algorithm include the following: step1: define the initial map data.

[0038] Step 2: Check the map data. If there is no non-emergency vehicle in the emergency lane, the algorithm ends. Otherwise, go to step 3.

[0039] Step 3: Define the valuation function f to estimate the time cost from the starting position to the empty target position, define the time function g to represent the actual time cost from the starting position to the current position, and define the heuristic function h to estimate the time cost from the current position to the empty target position, f=g+h. Define the time cost of each move of the non-emergency vehicle.

[0040] step4: Create an open list open_list and a closed list close_list, and initialize them to empty lists.

[0041] Step 5: Select the starting position of non-emergency vehicles and the clearing target position. Put the starting position as a checkpoint into the initial open_list.

[0042] Step 6: Calculate the f value of each node in the open_list. Select the node with the smallest f value from the open_list and use it as the current node. If the clear target position appears in the open_list, the shortest time path has been found. Otherwise, remove the current node from the open_list and save it to the close_list.

[0043] Step 7: According to the current position and expected turn of the non-emergency vehicle, consider the node to the left of the current node as an obstacle, check the adjacent extended nodes of the current node, if it is already in the close_list, skip it directly. If it is already in the open_list, recalculate the current g value, compare the current g value with the previous g value, select the smaller g value and update the f value, and update its parent node at the same time. If it is neither in the open_list nor in the close_list, put it in the open_list, confirm its parent node and f, g, h values. Go to step 6.

[0044] Step 8: Execute steps 5-7 again until all non-emergency vehicles have obtained the corresponding shortest time path from the starting position to the clearing target position. When all non-emergency vehicles have reached the clearing target position, the algorithm ends.

[0045] Step 4: Taking the minimum impact of non-emergency vehicles on emergency vehicles as the lower-level objective function, considering the lane change cost constraint of non-emergency vehicles, calculate the clearing heuristic point. The specific steps are as follows: Step 41: Take the impact of non-emergency vehicles on emergency vehicles as the minimum as the lower objective function, and ensure that emergency vehicles move at a constant speed. Driving towards the intersection, as shown in formulas (34)-(36), combined with formulas (8)-(33), the inspiration point that triggers the emergency lane to be cleared is calculated , thereby prompting non-emergency vehicles to leave the emergency lane: (34) (35) (36) In formulas (34), (35), and (36), is the relative speed between emergency vehicles and non-emergency vehicles, For non-emergency vehicles The lateral velocity, For the The total number of non-emergency vehicles on the emergency lane, The cumulative interference time of the non-emergency vehicle on the emergency vehicle is calculated based on the distance between the non-emergency vehicle and the emergency vehicle. and the impact of non-emergency vehicles on emergency vehicles The distance between the emergency vehicle and the nearest non-emergency vehicle in front is When , the emergency lane is cleared. In formula (36), is the impact of non-emergency vehicles on emergency vehicles. Under the premise of minimizing the total cost of non-emergency vehicles changing lanes, the optimization goal is to minimize the impact of non-emergency vehicles on emergency vehicles. The smaller the distance between the emergency vehicle and the nearest non-emergency vehicle in front, the less time it takes to clear the road section, the less cumulative interference time non-emergency vehicles have on emergency vehicles, and the smaller the impact of non-emergency vehicles on emergency vehicles. The minimum value of the impact of non-emergency vehicles on emergency vehicles is recorded as .

[0046] Step 5: Adopt the joint optimization method of the upper and lower objective functions. When the optimal value of the lane change cost of non-emergency vehicles in the upper model and the impact on emergency vehicles in the lower model converge and no longer change, terminate the iteration, output the final solution, determine the lane change plan and clearing inspiration point of non-emergency vehicles, and complete the emergency lane clearing task. The specific steps are as follows: Step 51: Starting from the minimum lane change cost of non-emergency vehicles in the upper model, the shortest lane change trajectory of each non-emergency vehicle is obtained, and then the upper and lower models are gradually iterated by jointly optimizing. After each iteration, the changing trends of the upper lane change cost and the lower emergency vehicle impact are checked. If the optimal values ​​of the two converge and remain unchanged in multiple consecutive iterations, the iteration is terminated.

[0047] Step 52: After the iteration is terminated, the optimal solutions of the current upper and lower layers are output, and the lane change plan and clearing inspiration point of the non-emergency vehicles in each dynamic clearing area are determined, so as to complete the clearing of the entire emergency lane.

[0048] Based on the embodiment, it is now assumed that the length of the grid is 10m, the width is 3.5m, the segment length of the cleared road section is 100m, the buffer length is 50m, the speed of the emergency vehicle is 20m / s, the speed of the non-emergency vehicle is uniformly 10m / s, the speed of the rally wave of the lane in front of the emergency vehicle is 11.5m / s, the duration of the iteration step is 1s, the length of the immutable road section is 50m, and the unit time cost during the duration of the emergency state when the emergency lane is dynamically cleared is 10. The mathematical model in step 3 is solved by the improved A* algorithm to calculate the shortest time lane change trajectory, the minimum total lane change cost and the clearing time of the non-emergency vehicle in the process of segmented clearing of the emergency lane. The specific situation is shown in Table 1.

[0049] According to the minimum total lane change cost of non-emergency vehicles calculated in step 3, the minimum impact and clearing inspiration point on emergency vehicles when clearing the emergency lane in sections are calculated through the objective function of step 4 and step 5. The specific situation is shown in Table 2.

[0050] After adopting the method of this application, the clearing time of the entire road section is 5s, the average clearing time is 1.67s, the minimum total lane change cost of non-emergency vehicles is 50, and the emergency vehicle travels on the emergency lane at a constant speed of 20m / s. The minimum impact on the emergency vehicle is 8707.25. The whole process of dynamic clearing of the emergency lane is as follows Figure 3a to Figure 3c This application divides the emergency lane into three clearing stages. In each stage, the corresponding section of the emergency lane is cleared only after the emergency vehicle reaches the clearing inspiration point. This allows non-emergency vehicles that are far away from the emergency vehicle to continue to drive safely on the emergency lane, thereby reducing vehicle delays at intersections and improving the traffic efficiency of emergency vehicles, demonstrating the effectiveness of the method of this application.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the above embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the above embodiments can still be modified, or some or all of the technical features can be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for dynamically clearing emergency lanes on urban roads based on intelligent network technology, characterized in that: The steps include: Step 1: Input the basic information of urban roads, including the number of lanes, length and width of the cleared road section; input the status information of vehicles on the cleared road section, including the position of emergency vehicles, the speed of emergency vehicles, the position of non-emergency vehicles, the speed of non-emergency vehicles and the expected turn; input the total number of non-emergency vehicles; input the gathering wave speed of the lane in front of the emergency vehicle; discretize the cleared road section; Step 2: Determine the scope of the dynamically cleared road section; Step 3: Based on the predicted turning of non-emergency vehicles, an upper-level model for dynamic clearance of emergency lanes is established. The total lane change cost of non-emergency vehicles is minimized as the upper-level objective function, and the improved A* algorithm is used to solve the problem and calculate the shortest lane change trajectory of each non-emergency vehicle. Step 4: Taking the minimum impact of non-emergency vehicles on emergency vehicles as the lower-level objective function, considering the lane change cost constraint of non-emergency vehicles, calculate the clearing heuristic point; Step 5: Adopt the joint optimization method of the upper and lower objective functions. When the optimal values ​​of the lane change cost of non-emergency vehicles in the upper model and the impact on emergency vehicles in the lower model converge and no longer change, terminate the iteration, output the final solution, determine the lane change plan and clearing inspiration point of non-emergency vehicles, and complete the emergency lane clearing task.

2. The method for dynamically clearing emergency lanes on urban roads based on intelligent network connection technology according to claim 1 is characterized in that: The step 1 comprises the following: Step 11: Use Indicates the number of lanes in the cleared section, using Indicates clearing the length of the road section, using Indicates lane width, using Indicates the lane number, ;use Indicates the location of the emergency vehicle, using represents the expected speed of the emergency vehicle, Indicates non-emergency vehicles location, use Indicates the speed of non-emergency vehicles, using Indicates non-emergency vehicles The expected turn of ,in Respectively indicate left turn, straight ahead, and right turn; represents the total number of non-emergency vehicles, ;use Represents the gathering wave speed of the lane ahead of the emergency vehicle; discretizes the cleared road section.

3. The method for dynamically clearing emergency lanes on urban roads based on intelligent network connection technology according to claim 2 is characterized in that: The step 2 includes the following: Step 21: Based on the discretization process in step 1, the vehicle driving direction is Axis, with lane distribution direction as A rectangular coordinate system consisting of several grid cells of the same size is established on the cleared road section. The position of each grid cell is determined by its horizontal coordinate. and the vertical coordinate Determine; the location of the grid cell where the emergency vehicle is located is ; The location of the grid cell where the non-emergency vehicle is located is ; The position of any vehicle in the cleared section is , the constraints are as shown in formulas (1)-(2): (1) (2) In the above formula, is the grid length, is the grid width; Step 22: After the rectangular coordinate system is established, the road section to be cleared is mapped in the coordinate system. The dynamic clearing range is divided into two cases. If there are no queued vehicles within the dynamic clearing range, the length and width of the dynamic clearing area are the segment lengths of the clearing section. , Lane width , the starting position of the dynamic clearing area is , then the dynamic clearing section range is defined as shown in formulas (3)-(4): (3) (4) If there are queued vehicles within the dynamic clearing range, the width of the dynamic clearing area remains unchanged, and the lateral range of the dynamic clearing section is defined as shown in formula (5): (5) In the above formula, is the length of the dynamic clearing area, and the calculation method is shown in formula (6): (6) In the above formula, is the length of the immutable road segment, To estimate the queue length upstream of the intersection at the moment; Based on the speed of the gathering wave in the lane ahead of the emergency vehicle and vehicle status information, The calculation method is shown in formula (7): (7) In the above formula, is the horizontal coordinate of the last connected vehicle stopped in the non-emergency vehicle queue, To estimate the time, The stopping time of the last connected vehicle in the non-emergency vehicle queue.

4. The method for dynamically clearing emergency lanes on urban roads based on intelligent network connection technology according to claim 3 is characterized in that: The step 3 includes the following: Step 31: Non-emergency vehicles on the emergency lane of urban roads Leave the emergency lane by moving or changing lanes; during the clearing process, non-emergency vehicles must avoid conflicts, as shown in formulas (8)-(10): (8) (9) (10) In formulas (8) and (9), is the number of iterations, is the duration of the iteration steps, is the maximum number of iterations, For non-emergency vehicles In the The horizontal coordinate of the step position, For non-emergency vehicles In the The vertical coordinate of the step position, For non-emergency vehicles In the The lateral speed of the step, For non-emergency vehicles In the The longitudinal speed of the step, For non-emergency vehicles In the The horizontal coordinate of the step position, For non-emergency vehicles In the The horizontal coordinate of the step position, For non-emergency vehicles In the The position of the step, For non-emergency vehicles In the The position of the step; Step 32: The emergency vehicle always drives in the emergency lane and its speed needs to maintain the expected speed unchanged, as shown in formulas (11)-(13): (11) (12) (13) In formula (11), For emergency vehicles The vertical coordinate of the step position, is the initial position ordinate of the emergency vehicle. In formula (12), For emergency vehicles The horizontal coordinate of the step position, For emergency vehicles The horizontal coordinate of the step position, For emergency vehicles The speed of the step, in formula (13), is the speed of the emergency vehicle at the initial position; Step 33: Ensure vehicle safety during dynamic clearing and limit the distance between the emergency vehicle and the nearest non-emergency vehicle ahead Not less than the buffer length , as shown in formulas (14)-(16): (14) (15) (16) In formula (14), For the The horizontal coordinate of the non-emergency vehicle closest to the emergency vehicle on the emergency lane; Step 34: When the emergency vehicle reaches the clearing inspiration point, the non-emergency vehicles on the emergency lane begin to leave the emergency lane to ensure a safe distance between vehicles; at the initial moment of clearing, the distance between the emergency vehicle and the nearest non-emergency vehicle in front is Should not be less than the buffer length , as shown in formulas (17)-(18): (17) (18) In formulas (17) and (18), is the initial position horizontal coordinate of the non-emergency vehicle closest to the emergency vehicle on the emergency lane, is the initial position abscissa of the emergency vehicle, The optimal value of is to clear the heuristic point ; Step 35: When the connected vehicles are about to enter the dynamically cleared road section, left-turning vehicles select the left-turn lane, straight-moving vehicles select the straight-moving lane, and right-turning vehicles select the rightmost lane; non-emergency vehicles expected to turn left only move and change lanes in the left-turn lane, non-emergency vehicles expected to go straight only move and change lanes in the straight-moving lane, and non-emergency vehicles expected to turn right only move in the right-turn lane, as shown in formulas (19)-(28): (19) (20) (21) (22) (23) (24) (25) (26) (27) (28) In the above formula, is a binary variable, The ordinate of the initial position of the non-emergency vehicle is equal to the lane number where it is located. ; For non-emergency vehicles The initial position ordinate of is a positive integer greater than or equal to 9999; Step 36: Calculate Non-Emergency Vehicles Time to reach the emptying target location , as shown in formulas (29)-(31): (29) (30) (31) In formula (29), For non-emergency vehicles The horizontal coordinate when reaching the clearing target position, For non-emergency vehicles The initial position abscissa, For non-emergency vehicles The vertical coordinate when reaching the clearing target position, and For non-emergency vehicles The time it takes for the vehicle to move forward and change lanes to the adjacent lane during the process of reaching the cleared target position; Step 37: When there are no non-emergency vehicles on the emergency lane, the emergency lane of the road section is cleared, as shown in formula (32): (32) In formula (32), The vertical coordinate of the emergency vehicle when the emergency lane is cleared; Step 38: Calculate the time it takes for all non-emergency vehicles that need to leave the emergency lane to reach the clearing target position, and combine the unit cost of the emergency state during the clearing process to form the total lane change cost of non-emergency vehicles. The minimum total lane change cost is used as the upper objective function, as shown in formula (33): (33) In formula (33), is the unit time cost during the duration of the emergency state when the emergency lane is dynamically cleared, is the total lane change cost of non-emergency vehicles, is the minimum total cost of lane change for non-emergency vehicles, and the objective function is the time it takes for all non-emergency vehicles that need to leave the emergency lane to reach the cleared target position. The minimum value of the unit time cost in the process The product of , i.e., the total lane change cost of non-emergency vehicles, represents the impact on non-emergency vehicles; Step 39: Taking the minimum total lane change cost of non-emergency vehicles as the goal, calculate the mathematical model of formula (33), and the shortest lane change trajectory of each non-emergency vehicle is recorded as , By non-emergency vehicle location Orderly composition; Step 310: Based on the principle of the shortest path, the initial positions of the non-emergency vehicles are matched with the unoccupied positions in the non-emergency lanes one by one to determine the starting position and the clearing target position of each non-emergency vehicle; Step 311: Use the improved A* algorithm to plan the path for each pair of starting position and clearing target position; in the emergency lane clearing task, non-emergency vehicles There are multiple feasible solutions for the lane change trajectory. If the entire map is traversed and searched, computing resources will be wasted on invalid paths. The improved A* algorithm is based on non-emergency vehicles. The current position and expected turn of non-emergency vehicles The left road section is considered as an obstacle, thus further narrowing the feasible search range of the current position. In addition, the heuristic function of the A* algorithm is improved to estimate the time cost from the current position to the clear target position; Through these optimizations, the shortest time path between the starting location of the non-emergency vehicle and the emptying target location is calculated ; Step 312: Calculate the shortest lane change trajectory of each non-emergency vehicle , calculated as follows: traversing the path , the first step of the path is set as the current position, and the next step is set as the target position; if the target position is occupied by multiple non-emergency vehicles at the same time, the conflicting vehicles will return to the previous step of the current position and replan the path with this position as the new starting position; If the target position is not occupied by other vehicles at the same time, the target position is switched to the current position, and the next step is to set it as the new target position, and then determine whether this position is occupied by multiple non-emergency vehicles at the same time; This process continues until all non-emergency vehicles have safely reached the clearing target location and the emergency lane of the road section has been cleared; In this process, the positions of non-emergency vehicles are arranged in order, and the shortest lane change trajectory of each non-emergency vehicle can be obtained. .

5. The method for dynamically clearing emergency lanes on urban roads based on intelligent network connection technology according to claim 4 is characterized in that: The operation steps of the improved A* algorithm in step 3 include the following: Step 1: Define the initial map data; Step 2: Check the map data. If there is no non-emergency vehicle in the emergency lane, the algorithm ends; otherwise, go to step 3; Step 3: Define the valuation function f to estimate the time cost from the starting position to the empty target position, define the time function g to represent the actual time cost from the starting position to the current position, and define the heuristic function h to estimate the time cost from the current position to the empty target position, f=g+h; define the time cost of each move of the non-emergency vehicle; step4: Create an open list open_list and a closed list close_list, and initialize them to empty lists; Step 5: Select the starting position of non-emergency vehicles and the clearing target position; put the starting position into the initial open_list as a point to be checked; Step 6: Calculate the f value of each node in the open_list; select the node with the smallest f value from the open_list and use it as the current node. If the clear target position appears in the open_list, the shortest time path has been found; otherwise, remove the current node from the open_list and save it to the close_list; Step 7: According to the current position and expected turn of the non-emergency vehicle, the left node of the current node is regarded as an obstacle, and the adjacent extended node of the current node is checked. If it is already in the close_list, it is skipped directly; if it is already in the open_list, the current g value is recalculated, and the current g value is compared with the previous g value. The smaller g value is selected and the f value is updated, and its parent node is updated at the same time; if it is neither in the open_list nor in the close_list, it is put into the open_list, and its parent node and f, g, and h values ​​are confirmed; go to step 6; Step 8: Execute steps 5-7 again until all non-emergency vehicles obtain the corresponding shortest time path from the starting position to the clearing target position; when all non-emergency vehicles reach the clearing target position, the algorithm ends.

6. The method for dynamically clearing emergency lanes on urban roads based on intelligent network connection technology according to claim 5 is characterized in that: The step 4 includes the following: Step 41: Take the impact of non-emergency vehicles on emergency vehicles as the minimum as the lower objective function, and ensure that emergency vehicles move at a constant speed. Driving towards the intersection, as shown in formulas (34)-(36), combined with formulas (8)-(33), the inspiration point that triggers the emergency lane to be cleared is calculated , thereby prompting non-emergency vehicles to leave the emergency lane: (34) (35) (36) In formulas (34), (35), and (36), is the relative speed between emergency vehicles and non-emergency vehicles, For non-emergency vehicles The lateral velocity, For the The total number of non-emergency vehicles on the emergency lane, The cumulative interference time of the non-emergency vehicle on the emergency vehicle is calculated based on the distance between the non-emergency vehicle and the emergency vehicle. and the impact of non-emergency vehicles on emergency vehicles The distance between the emergency vehicle and the nearest non-emergency vehicle in front is When the emergency lane is cleared, In formula (36), is the impact of non-emergency vehicles on emergency vehicles. Under the premise of minimizing the total cost of non-emergency vehicles changing lanes, the optimization goal is to minimize the impact of non-emergency vehicles on emergency vehicles. The smaller the distance between the emergency vehicle and the nearest non-emergency vehicle in front, the less time it takes to clear the road section, the less cumulative interference time non-emergency vehicles have on emergency vehicles, and the smaller the impact of non-emergency vehicles on emergency vehicles. The minimum value of the impact of non-emergency vehicles on emergency vehicles is recorded as .

7. The method for dynamically clearing emergency lanes on urban roads based on intelligent network connection technology according to claim 6 is characterized in that: The step 5 includes the following: Step 51: Starting from the minimum lane change cost of non-emergency vehicles in the upper model, the shortest lane change trajectory of each non-emergency vehicle is obtained, and then the upper and lower models are gradually iterated by jointly optimizing. After each iteration, the changing trends of the upper lane change cost and the lower emergency vehicle impact are checked. If the optimal values ​​of the two converge and remain unchanged in multiple consecutive iterations, the iteration is terminated; Step 52: After the iteration is terminated, the optimal solutions of the current upper layer and the lower layer are output, and the lane change plan and clearing inspiration point of the non-emergency vehicle in each dynamic clearing area are determined, so as to complete the clearing of the entire emergency lane.

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