Dynamic Emptying Method for Emergency Lanes on Urban Roads Based on Intelligent Networked Technology

Abstract

The present application provides a method for dynamically clearing the emergency lane of urban roads based on intelligent network connection technology, belonging to the field of intelligent traffic control. First, collect the basic information of urban roads, the vehicle status information on the clearing section, the total number of non-emergency vehicles, and the gathering wave speed of the lane in front of the emergency vehicle, and discretize the clearing section; then, determine the range of the dynamic clearing section, and based on the turning information of non-emergency vehicles, establish an upper-layer model with the goal of minimizing the total lane-changing cost of non-emergency vehicles, and use an improved A* algorithm to calculate the shortest-time lane-changing trajectory of non-emergency vehicles; finally, based on the lane-changing cost of non-emergency vehicles, establish a lower-layer model with the goal of minimizing the impact on emergency vehicles, calculate the clearing heuristic point, and realize the dynamic clearing of the emergency lane of urban roads. The present application takes into account the expected turning of vehicles, reduces the delay of non-emergency vehicles at intersections and the impact on the normal driving of emergency vehicles, thereby improving the passing efficiency of emergency vehicles.

Description

Technical Field

[0001] This application belongs to the field of intelligent transportation control, and particularly relates to a method for dynamically clearing the emergency lane of urban roads based on intelligent network connection technology. Background Art

[0002] With the continuous development of society, 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 traffic obstacles. The traditional traffic management method lacks sufficient flexibility and intelligence, resulting in the difficulty for emergency vehicles to reach the accident or emergency site in time, which greatly affects the realization of their right of way priority. The technical method for preferential control of emergency vehicles can improve the urban emergency rescue efficiency, relieve the overall traffic pressure, and also provide strong support for improving the comprehensive management level of the urban traffic system.

[0003] The existing preferential methods for emergency vehicles mostly focus on signal priority control based on the time dimension. By switching to a pre-established or adaptive signal control scheme, a green light phase is provided for emergency vehicles at intersections. However, relying solely on the priority control in the time dimension has limited effects in the complex urban road environment. Due to the large urban traffic flow, it is difficult for emergency vehicles to obtain priority on urban roads, which weakens the effectiveness of the signal priority method and leads to a larger range of traffic delays.

[0004] Therefore, this application aims to optimize the priority passage of emergency vehicles in the spatial dimension, thereby reducing the overall traffic delay. The current technical solutions usually set up dedicated emergency lanes or conduct manual traffic control, relying on human intervention, with a low degree of automation, and it is difficult to respond to emergencies in real time, affecting the traffic efficiency of emergency vehicles. The rapid development of intelligent network connection technology provides new solutions and technical support for urban traffic management. Through vehicle networking technology, the traffic situation can be monitored in real time, the use of the emergency lane can be optimized, non-emergency vehicles can be coordinated, and the obstruction to emergency vehicles can be reduced to meet their need for rapid passage in a more accurate manner.

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

[0006] In this context, the present application proposes a method for dynamically clearing the emergency lane on urban roads based on intelligent network connection technology. According to the information such as the position, speed, and expected turning of connected vehicles, this method first optimizes the lane-changing trajectories of non-emergency vehicles to reduce the delay of non-emergency vehicles. Then, from the perspective of 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 emergency vehicles. By triggering the clearing multiple times, the dynamic clearing of the emergency lane is achieved, which is the main problem to be solved by the present application. Summary of the Invention

[0007] Aiming at the deficiencies of existing research, the present application provides a method for dynamically clearing the emergency lane on urban roads based on intelligent network connection technology. Considering the expected turning of non-emergency vehicles, a two-layer model is established. The upper layer is to plan the shortest-time lane-changing trajectory of non-emergency vehicles to minimize the total lane-changing cost, thereby reducing the impact on non-emergency vehicles. The lower layer is to calculate the clearing heuristic point with the least impact on emergency vehicles on the premise of meeting the minimum total lane-changing cost of non-emergency vehicles, realizing the dynamic clearing of the emergency lane on urban roads, improving the passing efficiency of emergency vehicles, and reducing the vehicle delay at intersections.

[0008] The method for dynamically clearing the emergency lane on urban roads based on intelligent network connection technology provided by the present application includes the following steps:

[0009] Step 1: Input the basic information of the urban road, where the basic information of the urban road includes the number of lanes, the length of the clearing section, and the lane width of the clearing section; input the status information of the vehicles on the clearing section, where the status information of the vehicles on the clearing section includes the position of the emergency vehicle, the speed of the emergency vehicle, the position of the non-emergency vehicle, the speed of the non-emergency vehicle, and the expected turning; input the total number of non-emergency vehicles; input the gathering wave speed of the lane in front of the emergency vehicle; discretize the clearing section.

[0010] Step 2: Determine the range of the dynamic clearing section;

[0011] Step 3: Based on the expected turning of non-emergency vehicles, establish the upper-layer model for dynamically clearing the emergency lane. With the minimum total lane-changing cost of non-emergency vehicles as the upper-layer objective function, use the improved A* algorithm to solve it, and calculate the shortest-time lane-changing trajectories of each non-emergency vehicle.

[0012] Step 4: With the least impact of non-emergency vehicles on emergency vehicles as the lower-layer objective function, considering the lane-changing cost constraint of non-emergency vehicles, calculate the clearing heuristic point.

[0013] Step 5: Adopt the joint optimization method of the upper and lower layer objective functions. When the non-emergency vehicle lane-changing cost of the upper layer model and the optimal value of the impact on emergency vehicles of the lower layer model converge and no longer change, terminate the iteration, output the final solution, determine the lane-changing plan of non-emergency vehicles and clear the heuristic points, and complete the task of clearing the emergency lane.

[0014] In one possible implementation manner, for the urban road emergency lane dynamic clearing method provided by the embodiments of the present application, the step 1 includes the following:

[0015] Step 11: Use to represent the number of lanes in the cleared section, use to represent the length of the cleared section, use to represent the lane width, use to represent the lane number, ; use to represent the position of the emergency vehicle, use to represent the expected speed of the emergency vehicle, use to represent the non-emergency vehicle 's position, use to represent the non-emergency vehicle 's speed, use to represent the non-emergency vehicle 's expected steering, , where , , respectively represent left turn, straight ahead, and right turn; use to represent the total number of non-emergency vehicles, ; use to represent the gathering wave speed of the lane in front of the emergency vehicle; discretize the cleared section.

[0016] In one possible implementation manner, for the urban road emergency lane dynamic clearing method provided by the embodiments of the present application, in the step 2, determining the range of the dynamic clearing section includes the following steps:

[0017] Step 21: According to the discretization process in step 1, with the vehicle driving direction as the axis and the lane distribution direction as the axis, establish a rectangular coordinate system composed of several grid units of the same size on the cleared section. The position of each grid unit is determined by the abscissa and the ordinate where it is located; the position of the grid unit where the emergency vehicle is located is the position of the grid unit where the non-emergency vehicle is located is ; the position of any vehicle on the cleared section is, and the constraints are shown in formulas (1)-(2):

[0018] (1)

[0019] (2)

[0020] In the above formula, is the grid length, is the grid width;

[0021] Step 22: After establishing the rectangular coordinate system, the section to be cleared is mapped in this coordinate system. The determination of the dynamic clearance range is divided into two cases. If there are no queuing vehicles within the dynamic clearance range, the length and width of the dynamic clearance area are respectively the segmented length of the cleared section, the lane width, and the starting position of the dynamic clearance area is

[0022] (3)

[0023] (4)

[0024] If there are queuing vehicles within the dynamic clearance range, the width of the dynamic clearance area remains unchanged, and the horizontal range of the dynamic clearance section is determined as shown in formula (5):

[0025] (5)

[0026] In the above formula, is the length of the dynamic clearance area, and the calculation method is as shown in formula (6):

[0027] (6)

[0028] In the above formula, is the length of the immutable road section, is the queuing length upstream of the intersection at the estimated time; according to the aggregation wave speed of the lane in front of the emergency vehicle and the status information of the vehicle, the calculation method is as shown in formula (7):

[0029] (7)

[0030] In the above formula, is the abscissa of the last connected vehicle that stops in the non-emergency vehicle queue, is the estimated time, is the parking time of the last connected vehicle that stops in the non-emergency vehicle queue.

[0031] In one possible implementation, for the method for dynamically clearing the emergency lane on urban roads provided by the embodiments of the present application based on intelligent network connection technology, in step 3, an upper-layer model for dynamically clearing the emergency lane is established based on the predicted steering of non-emergency vehicles. With the minimum total lane-changing cost of non-emergency vehicles as the upper-layer objective function, an improved A* algorithm is used for solving to calculate the shortest-time lane-changing trajectories of each non-emergency vehicle, including the following steps:

[0032] 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, conflicts between non-emergency vehicles must be avoided, as shown in formulas (8)-(10):

[0033] (8)

[0034] (9)

[0035] (10)

[0036] In formulas (8) and (9), is the number of iterations, is the duration of each iteration step, is the maximum number of iterations, is non-emergency vehicle at the horizontal coordinate of the position at the step, at the vertical coordinate of the position at the step, at the horizontal speed at the step, at the vertical speed at the step, horizontal coordinate of the position at the +1 step, at the horizontal coordinate of the position at the +1 step, at the position at the step, at the position at the step;

[0037] Step 32: The emergency vehicle always travels on the emergency lane, and its speed needs to remain at the desired speed constant, as shown in formulas (11)-(13):

[0038] (11)

[0039] (12)

[0040] (13)

[0041] In formula (11), is the ordinate of the emergency vehicle at the -th step, is the initial ordinate of the emergency vehicle. In formula (12), is the abscissa of the emergency vehicle at the -th step, is the abscissa of the emergency vehicle at the -th step, is the speed of the emergency vehicle at the -th step. In formula (13), is the speed of the emergency vehicle at the initial position;

[0042] Step 33: To ensure the safety of vehicle driving during dynamic clearance, the distance between the emergency vehicle and the nearest non-emergency vehicle ahead is restricted to be not less than the buffer length , as shown in formulas (14)-(16):

[0043] (14)

[0044] (15)

[0045] (16)

[0046] In formula (14), is the abscissa of the non-emergency vehicle closest to the emergency vehicle on the emergency lane at the -th step;

[0047] Step 34: When the emergency vehicle reaches the clearance trigger point, the non-emergency vehicles on the emergency lane start to leave the emergency lane to ensure a safe distance between vehicles; at the initial moment of clearance, the distance between the emergency vehicle and the nearest non-emergency vehicle ahead should be not less than the buffer length , as shown in formulas (17)-(18):

[0048] (17)

[0049] (18)

[0050] In formulas (17) and (18), is the abscissa of the initial position of the non-emergency vehicle closest to the emergency vehicle on the emergency lane, is the abscissa of the initial position of the emergency vehicle, The optimal value of is to clear the heuristic point ;

[0051] Step 35: When the connected vehicle is about to enter the section with dynamic clearance, the left-turn vehicle selects the left-turn lane, the straight-ahead vehicle selects the straight-ahead lane, and the right-turn vehicle selects the rightmost lane; the non-emergency vehicle expected to turn left only moves and changes lanes on the left-turn lane, the non-emergency vehicle expected to go straight only moves and changes lanes on the straight-ahead lane, and the non-emergency vehicle expected to turn right only moves on the right-turn lane, as shown in formulas (19)-(28):

[0052] (19)

[0053] (20)

[0054] (21)

[0055] (22)

[0056] (23)

[0057] (24)

[0058] (25)

[0059] (26)

[0060] (27)

[0061] (28)

[0062] In the above formula, is a binary variable, represents that the ordinate of the initial position of the non-emergency vehicle is equal to its lane number at the initial moment, otherwise ; is the ordinate of the initial position of the non-emergency vehicle ; is a positive integer greater than or equal to 9999;

[0063] Step 36: Calculate the time for the non-emergency vehicle to reach the cleared target position , as shown in formulas (29)-(31):

[0064] (29)

[0065] (30)

[0066] (31)

[0067] In formula (29), is the abscissa of the non-emergency vehicle when it reaches the clearing target position, is the abscissa of the initial position of the non-emergency vehicle , is the ordinate of the non-emergency vehicle when it reaches the clearing target position, and are the times respectively spent by the non-emergency vehicle in moving forward and changing lanes to the adjacent lane during the process of reaching the clearing target position;

[0068] Step 37: When there are no non-emergency vehicles on the emergency lane, the clearing of the emergency lane for this section is completed, as shown in formula (32):

[0069] (32)

[0070] In formula (32), is the ordinate of the emergency vehicle when the emergency lane is cleared;

[0071] Step 38: Calculate the time for all non-emergency vehicles that need to leave the emergency lane to reach the clearing target position, and combine the unit cost during the continuous emergency state during the clearing process to form the total lane-changing cost of the non-emergency vehicles. Taking the minimum of this total lane-changing cost as the upper-layer objective function, as shown in formula (33):

[0072] (33)

[0073] In formula (33), is the unit time cost during the continuous emergency state when dynamically clearing the emergency lane, is the total lane-changing cost of the non-emergency vehicles, is the minimum value of the total lane-changing cost of the non-emergency vehicles. The objective function is the product of the minimum value of the time consumed for all non-emergency vehicles that need to leave the emergency lane to reach the clearing target position and the unit time cost in this process, that is, the total lane-changing cost of the non-emergency vehicles, which represents the impact on the non-emergency vehicles;

[0074] Step 39: Taking the minimum total cost of non-emergency vehicle lane changes as the goal, calculate the mathematical model of formula (33), and record the shortest-time lane change trajectories of each non-emergency vehicle as , which are orderly composed of the positions of non-emergency vehicles ;

[0075] Step 310: Based on the principle of the shortest path, match the initial positions of non-emergency vehicles with the unoccupied positions in the non-emergency lane one by one to determine the starting positions and cleared target positions of each non-emergency vehicle;

[0076] Step 311: Use the improved A* algorithm to perform path planning for each pair of starting positions and cleared target positions; in the emergency lane clearing task, there are multiple feasible solutions for the lane change trajectories of non-emergency vehicles . If the entire map is traversed and searched, it will cause computational resources to be wasted on invalid paths; the improved A* algorithm regards the left section of the non-emergency vehicle as an obstacle according to the current position and expected turning of the non-emergency vehicle, 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 cleared target position; through these optimizations, calculate the shortest-time path between the starting position and the cleared target position of the non-emergency vehicle ; ;

[0077] Step 312: Calculate the shortest-time lane change trajectories of each non-emergency vehicle , and the calculation method is as follows: Traverse the path , set the first step of the path as the current position and the next step 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 re-plan the path with this position as the new starting position; if the target position is not occupied by other vehicles at the same time, switch the target position to the current position, set the next step 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 safely reach the cleared target position and the emergency lane of this section is cleared; during this process, the positions of non-emergency vehicles are orderly arranged, and the shortest-time lane change trajectories of each non-emergency vehicle can be obtained .

[0078] In one possible implementation manner, for the method for dynamically clearing the emergency lane of an urban road provided by the embodiment of the present application based on intelligent network connection technology, the operation steps of the improved A* algorithm in step 3 include the following:

[0079] step1: Define the initial map data;

[0080] Step 2: Check the map data. If there are no non-emergency vehicles in the emergency lane, the algorithm ends; otherwise, go to Step 3.

[0081] Step 3: Define an evaluation function f to estimate the time cost from the starting position to the cleared target position, define a time function g to represent the actual time cost from the starting position to the current position, define a heuristic function h to estimate the time cost from the current position to the cleared target position, and f = g + h; define the time cost for each step of the non-emergency vehicle's movement.

[0082] Step 4: Create an open list open_list and a closed list close_list, and initialize them as empty lists.

[0083] Step 5: Select the starting position and the cleared target position of the non-emergency vehicle; put the starting position as a checkpoint to be inspected into the initialized open_list.

[0084] 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 take it as the current node. If the cleared target position appears in the open_list, the shortest time-consuming path has been found at this time; otherwise, remove the current node from the open_list and transfer it to the close_list.

[0085] Step 7: Regarding the left node of the current node as an obstacle according to the current position and the expected turning direction of the non-emergency vehicle, check the adjacent expanded 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 into the open_list, confirm its parent node and the f, g, h values; go to Step 6.

[0086] Step 8: Execute Steps 5 - 7 again until the corresponding shortest time-consuming paths from the starting position to the cleared target position are obtained for all non-emergency vehicles; when all non-emergency vehicles reach the cleared target position, the algorithm ends.

[0087] In one possible implementation manner, for the method for dynamically clearing the emergency lane of an urban road provided by the embodiment of the present application based on intelligent networking technology, in the said Step 4, taking the minimum impact of non-emergency vehicles on emergency vehicles as the lower-layer objective function and considering the cost constraint of non-emergency vehicle lane changes, calculate the clearing heuristic point, including the following steps:

[0088] Step 41: Taking the minimum impact of non-emergency vehicles on emergency vehicles as the lower-layer objective function, ensuring that emergency vehicles drive towards the intersection at a constant speed as shown in formulas (34)-(36), combined with formulas (8)-(33), calculate the heuristic points for triggering the evacuation of the emergency lane , thereby prompting non-emergency vehicles to drive off the emergency lane:

[0089] (34)

[0090] (35)

[0091] (36)

[0092] In formulas (34), (35), and (36), is the relative speed between the emergency vehicle and the non-emergency vehicle, is the non-emergency vehicle 's lateral speed, is the th step of the total number of non-emergency vehicles on the emergency lane, is the cumulative interference time of non-emergency vehicles on emergency vehicles, and this time is weighted according to the distance between non-emergency vehicles and emergency vehicles and the influence intensity of non-emergency vehicles on emergency vehicles . When the distance between the emergency vehicle and the nearest non-emergency vehicle in front is , trigger the evacuation of the emergency lane; in formula (36), is the influence of non-emergency vehicles on emergency vehicles. On the premise that the total cost of non-emergency vehicle lane-changing is minimized, taking the minimum impact of non-emergency vehicles on emergency vehicles as the optimization goal, the smaller the distance between the emergency vehicle and the nearest non-emergency vehicle in front, the less time required to complete the evacuation of the section, the less the cumulative interference time of non-emergency vehicles 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 denoted as .

[0093] In one possible implementation manner, for the dynamic evacuation method of urban road emergency lanes provided by the embodiments of the present application based on intelligent networking technology, in the said step 5, a combined optimization method of upper and lower layer objective functions is adopted. When the optimal values of the non-emergency vehicle lane-changing cost of the upper layer model and the impact on emergency vehicles of the lower layer model converge and no longer change, terminate the iteration, output the final solution, determine the lane-changing plan of non-emergency vehicles and the evacuation heuristic points, and complete the evacuation task of the emergency lane, including the following steps:

[0094] Step 51: Start from the minimum non-emergency vehicle lane-changing cost of the upper-layer model to obtain the shortest-time lane-changing trajectories of non-emergency vehicles. Then, gradually iterate by jointly optimizing the upper and lower-layer models. After each iteration, check the changing trends of the upper-layer lane-changing cost and the impact of lower-layer emergency vehicles. If the optimal values of both converge and remain unchanged in multiple consecutive iterations, terminate the iteration.

[0095] Step 52: After the iteration terminates, output the optimal solutions of the current upper and lower layers, determine the lane-changing schemes and clearing heuristic points of non-emergency vehicles in each dynamic clearing area, thereby completing the clearing of the entire emergency lane.

[0096] Beneficial effects: The urban road emergency lane dynamic clearing method based on intelligent connected technology provided by this application has the following advantages compared with the prior art:

[0097] By constructing a two-layer programming model, the passing efficiency and safety of emergency vehicles are effectively improved. This application comprehensively considers the expected turning of non-emergency vehicles, takes minimizing the total lane-changing cost of non-emergency vehicles as the upper-layer objective, and minimizing the impact of non-emergency vehicles on emergency vehicles as the lower-layer objective, thereby guiding non-emergency vehicles to drive out of the emergency lane and reach the clearing target position in the shortest time, reducing vehicle delays at intersections, and minimizing the impact on the normal driving of emergency vehicles to the greatest extent.

[0098] Using the expected turning information in the intelligent connected environment, the feasible search range of the existing algorithm is narrowed, and the waste of computing resources on invalid lane-changing trajectories of non-emergency vehicles is reduced. At the same time, combined with urban traffic rules and intersection signal phase states, the range of the dynamic clearing section is determined, the shortest-time lane-changing scheme and the best clearing heuristic point of non-emergency vehicles are calculated, so that the emergency lane can be dynamically cleared in segments as the emergency vehicle travels, ensuring the priority passing of emergency vehicles on complex urban roads. Description of the Drawings

[0099] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of this application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0100] Figure 1 is a flowchart of the urban road emergency lane dynamic clearing method based on intelligent connected technology provided by this application;

[0101] Figure 2 is a schematic diagram of the dynamic clearing of the urban road emergency lane in the urban road emergency lane dynamic clearing method based on intelligent connected technology provided by this application;

[0102] Figure 3a It is a schematic diagram of emptying the emergency lane in the first stage by sections;

[0103] Figure 3b It is a schematic diagram of emptying the emergency lane in the second stage by sections;

[0104] Figure 3c It is a schematic diagram of emptying the emergency lane in the third stage by sections. Specific implementation manners

[0105] The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present application, and should not be construed as limiting the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the scope of protection of the present application.

[0106] See Figure 1 and Figure 2 According to the present application, the overall control logic of the method for dynamically emptying the emergency lane of urban roads based on intelligent connected technology is as follows: collecting the state information of vehicles on the section to be emptied through intelligent connected technology, and combining the basic information of urban roads to discretize the emptied section. Based on urban traffic rules and the signal phase state of intersections, determine the range of the dynamically emptied section. The emergency lane is emptied dynamically section by section to solve the problem of the priority passage of emergency vehicles in a complex urban road environment. For the emptying of each section of the emergency lane, the present application calculates the shortest time-varying lane-changing trajectories of non-emergency vehicles and the heuristic points for triggering the emptying of the emergency lane based on the predicted turning information of non-emergency vehicles obtained through intelligent connected technology, and forms a dynamic emptying plan for the emergency lane. The dynamic emptying plan is distributed to non-emergency vehicles and emergency vehicles through intelligent connected technology to ensure that emergency vehicles can pass through the corresponding section safely and efficiently with the least impact. Emergency vehicles arrive at the emptying heuristic points of each section of the emergency lane in turn, and finally complete the task of emptying the emergency lane.

[0107] Combined with the accompanying drawings and embodiments, the technical solution of the present application is described in detail as follows:

[0108] The method for dynamically emptying the emergency lane of urban roads based on intelligent connected technology provided by the present application includes the following steps:

[0109] Step 1: Input the basic information of urban roads, where the basic information of urban roads includes the number of lanes, the length of the emptied section, and the lane width of the emptied section. Input the state information of vehicles on the emptied section, where the state information of vehicles on the emptied section includes the position of emergency vehicles, the speed of emergency vehicles, the position of non-emergency vehicles, the speed of non-emergency vehicles, and the predicted turning. Input the total number of non-emergency vehicles. Input the aggregation wave speed of the lane in front of the emergency vehicle. Discretize the emptied section, and the specific steps are as follows:

[0110] Step 11: Use to represent the number of lanes in the cleared section, use to represent the length of the cleared section, use to represent the lane width, use to represent the lane number, . Use to represent the position of the emergency vehicle, use to represent the expected speed of the emergency vehicle, use to represent non-emergency vehicles 's position, use to represent non-emergency vehicles 's speed, use to represent non-emergency vehicles 's expected turning direction, , where , , represent left turn, straight ahead, and right turn respectively. Use to represent the total number of non-emergency vehicles, . Use to represent the speed of the platoon wave in the lane in front of the emergency vehicle. Discretize the cleared section.

[0111] In the 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 500 m, and the lane width is 3.5 m; the expected speed of the emergency vehicle is 20 m / s. At a certain moment, the positions, numbers, and lane numbers of non-emergency vehicles on the cleared section are as Figures 3a to 3c shown. Among them, the expected turning direction of the vehicle in lane 4 is a left turn, the expected turning direction of the vehicle in lane 3 is a straight ahead or a left turn, the expected turning direction of the vehicle in lane 2 is a straight ahead, the expected turning direction of the vehicle in lane 1 is a right turn, and the driving speed of non-emergency vehicles is uniformly 10 m / s; the speed of the platoon wave in the lane in front of the emergency vehicle is 1.5 m / s; the cleared section is discretized.

[0112] Step 2: Determine the dynamic cleared section range. The specific steps are as follows:

[0113] Step 21: According to the discretization process in Step 1, with the vehicle driving direction as the axis and the lane distribution direction as the axis, establish a rectangular coordinate system on the cleared section composed of several grid cells of the same size. The position of each grid cell is determined by the abscissa and the ordinate . 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 located is . The position of any vehicle on the cleared section is , the constraints are shown in Formulas (1)-(2):

[0114] (1)

[0115] (2)

[0116] In the above formulas, is the grid length, is the grid width.

[0117] Step 22: After establishing the rectangular coordinate system, the road section to be cleared is mapped in this coordinate system. The determination of the dynamic clearance range is divided into two cases. If there are no queuing vehicles within the dynamic clearance range, the length and width of the dynamic clearance area are respectively the segmented length of the cleared road section, the lane width, and the starting position of the dynamic clearance area is

[0118] (3)

[0119] (4)

[0120] If there are queuing vehicles within the dynamic clearance range, the width of the dynamic clearance area remains unchanged, and the horizontal range of the dynamic clearance road section is determined as shown in Formula (5):

[0121] (5)

[0122] In the above formula, is the length of the dynamic clearance area, and the calculation method is shown in Formula (6):

[0123] (6)

[0124] In the above formula, is the length of the immutable road section, is the queuing length upstream of the intersection at the estimation moment. According to the gathering wave speed of the lane in front of the emergency vehicle and the status information of the vehicle, the calculation method is shown in Formula (7):

[0125] (7)

[0126] In the above formula, is the abscissa of the last connected vehicle that stops in the non-emergency vehicle queue, is the estimation moment, is the parking moment of the last connected vehicle that stops in the non-emergency vehicle queue.

[0127] Step 3: Based on the predicted steering of non-emergency vehicles, establish an upper-layer model for dynamic clearance of the emergency lane. With the minimum total lane-changing cost of non-emergency vehicles as the upper-layer objective function, use the improved A* algorithm to solve it, and calculate the shortest time-consuming lane-changing trajectories of each non-emergency vehicle. The specific steps are as follows:

[0128] Step 31: Non-emergency vehicles on the emergency lane of the urban road leave the emergency lane by moving or changing lanes. During the clearance process, conflicts between non-emergency vehicles must be avoided, as shown in formulas (8)-(10):

[0129] (8)

[0130] (9)

[0131] (10)

[0132] In formulas (8) and (9), is the number of iterations, is the duration of each iteration step, is the maximum number of iterations, is non-emergency vehicle at the horizontal coordinate of the position at the step, at the vertical coordinate of the position at the step, at the horizontal speed at the step, at the vertical speed at the step, and is the horizontal coordinate of the position at the +1 step, at the horizontal coordinate of the position at the step, at the position at the step, at the position at the

[0133] Step 32: Emergency vehicles always drive on the emergency lane, and their speed needs to remain at the desired speed unchanged, as shown in formulas (11)-(13):

[0134] (11)

[0135] (12)

[0136] (13)

[0137] In formula (11), is the ordinate of the emergency vehicle's position at the th step, is the ordinate of the emergency vehicle's initial position. In formula (12), is the abscissa of the emergency vehicle's position at the th step, is the abscissa of the emergency vehicle's position at the th step, is the speed of the emergency vehicle at the th step. In formula (13), is the speed of the emergency vehicle at the initial position.

[0138] Step 33: To ensure the safety of vehicle travel during dynamic clearance, the distance between the emergency vehicle and the nearest non-emergency vehicle ahead is restricted to be not less than the buffer length , as shown in formulas (14)-(16):

[0139] (14)

[0140] (15)

[0141] (16)

[0142] In formula (14), is the abscissa of the non-emergency vehicle closest to the emergency vehicle on the emergency lane at the th step.

[0143] Step 34: When the emergency vehicle reaches the clearance heuristic point, the non-emergency vehicles on the emergency lane start to leave the emergency lane to ensure a safe distance between vehicles. At the initial moment of clearance, the distance between the emergency vehicle and the nearest non-emergency vehicle ahead should be not less than the buffer length , as shown in formulas (17)-(18):

[0144] (17)

[0145] (18)

[0146] In formulas (17) and (18), is the abscissa of the initial position of the non-emergency vehicle closest to the emergency vehicle on the emergency lane, is the abscissa of the initial position of the emergency vehicle The optimal value of is to clear the heuristic point

[0147] Step 35: When the connected vehicle is about to enter the section where dynamic clearance is to be carried out, the left-turning vehicle selects the left-turn lane, the straight-going vehicle selects the straight lane, and the right-turning vehicle selects the rightmost lane. It is expected that the non-emergency vehicle turning left will only move and change lanes on the left-turn lane, the non-emergency vehicle going straight will only move and change lanes on the straight lane, and the non-emergency vehicle turning right will only move on the right-turn lane, as shown in formulas (19)-(28):

[0148] (19)

[0149] (20)

[0150] (21)

[0151] (22)

[0152] (23)

[0153] (24)

[0154] (25)

[0155] (26)

[0156] (27)

[0157] (28)

[0158] In the above formula, is a binary variable represents that the ordinate of the initial position of the non-emergency vehicle is equal to its lane number, otherwise is the ordinate of the initial position of the non-emergency vehicle is a positive integer greater than or equal to 9999

[0159] Step 36: Calculate the time when the non-emergency vehicle reaches the clearance target position, as shown in formulas (29)-(31):

[0160] (29) ​​

[0161] (30)

[0162] (31)

[0163] In formula (29), is the non-emergency vehicle the abscissa when reaching the clearance target position, is the non-emergency vehicle the abscissa of the initial position, is the non-emergency vehicle the ordinate when reaching the clearance target position, and is the non-emergency vehicle the time taken for the vehicle to move forward and change lanes to the adjacent lane respectively during the process of reaching the clearance target position.

[0164] Step 37: When there is no non-emergency vehicle on the emergency lane, the emergency lane of this section is cleared, as shown in formula (32):

[0165] (32)

[0166] In formula (32), is the ordinate of the emergency vehicle when the emergency lane is cleared.

[0167] Step 38: Calculate the time for all non-emergency vehicles that need to leave the emergency lane to reach the clearance target position, and combine the unit cost during the emergency continuous state in the clearance process to form the total lane-changing cost of non-emergency vehicles. Taking the minimum of this total lane-changing cost as the upper-layer objective function, as shown in formula (33):

[0168] (33)

[0169] In formula (33), is the unit time cost during the emergency state duration when dynamically clearing the emergency lane, is the total lane-changing cost of non-emergency vehicles, is the minimum value of the total lane-changing cost of non-emergency vehicles. The objective function is the product of the minimum value of the time consumed for all non-emergency vehicles that need to leave the emergency lane to reach the clearance target position and the unit time cost in this process, that is, the total lane-changing cost of non-emergency vehicles, representing the impact on non-emergency vehicles.

[0170] Step 39: Taking the minimum of the total lane-changing cost of non-emergency vehicles as the goal, calculate the mathematical model of formula (33), and record the shortest time-consuming lane-changing trajectory of each non-emergency vehicle as , Composed of the positions of non-emergency vehicles in an orderly manner.

[0171] Step 310: Based on the principle of the shortest path, match the initial positions of non-emergency vehicles with the unoccupied positions in the non-emergency lane one by one to determine the starting positions and clearance target positions of each non-emergency vehicle.

[0172] Step 311: Use the improved A* algorithm to perform path planning for each pair of starting positions and clearance target positions. In the emergency lane clearance task, there are multiple feasible solutions for the lane-changing trajectories of non-emergency vehicles. If the entire map is traversed and searched, it will cause computational resources to be wasted on invalid paths. The improved A* algorithm regards the left section of the non-emergency vehicle as an obstacle according to the current position and expected turning of the non-emergency vehicle, 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 clearance target position. Through these optimizations, calculate the shortest-time path between the starting position and the clearance target position of the non-emergency vehicle .

[0173] Step 312: Calculate the shortest-time lane-changing trajectories of each non-emergency vehicle , and the calculation method is as follows: Traverse the path , set the first step of the path as the current position, and the next step 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 re-plan the path with this position as the new starting position. If the target position is not occupied by other vehicles at the same time, switch the target position to the current position, set the next step 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 safely reach the clearance target position and the emergency lane of this section is cleared. During this process, the positions of non-emergency vehicles are arranged in an orderly manner, and the shortest-time lane-changing trajectories of each non-emergency vehicle can be obtained .

[0174] Among them, the operation steps of the improved A* algorithm include the following:

[0175] step1: Define the initial map data.

[0176] step2: Check the map data. If there are no non-emergency vehicles in the emergency lane, the algorithm ends. Otherwise, go to step3.

[0177] ​​Step 3: Define the evaluation function f to estimate the time cost from the starting position to the cleared 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 cleared target position. f = g + h. Define the time cost for each step of the non-emergency vehicle's movement.

[0178] Step 4: Create an open list open_list and a closed list close_list, and initialize them as empty lists.

[0179] Step 5: Select the starting position and the cleared target position of the non-emergency vehicle. Put the starting position as a checkpoint to be inspected into the initialized open_list.

[0180] 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 make it the current node. When the cleared target position appears in the open_list, the shortest time-consuming path has been found at this time. Otherwise, remove the current node from the open_list and transfer it to the close_list.

[0181] Step 7: Regarding the left node of the current node as an obstacle according to the current position and the expected turning of the non-emergency vehicle, check the adjacent expanded 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 into the open_list, and confirm its parent node as well as the f, g, and h values. Go to Step 6.

[0182] Step 8: Execute Steps 5 - 7 again until the corresponding shortest time-consuming paths for all non-emergency vehicles from the starting position to the cleared target position are obtained. When all non-emergency vehicles reach the cleared target position, the algorithm ends.

[0183] Step 4: Taking the minimum impact of non-emergency vehicles on emergency vehicles as the lower-level objective function and considering the lane-changing cost constraint of non-emergency vehicles, calculate the clearing heuristic points. The specific steps are as follows:

[0184] Step 41: Taking the minimum impact of non-emergency vehicles on emergency vehicles as the lower-level objective function, ensure that the emergency vehicle drives towards the intersection at a constant speed as shown in formulas (34) - (36), and combining with formulas (8) - (33), calculate the heuristic points for triggering the clearing of the emergency lane , so as to prompt non-emergency vehicles to drive out of the emergency lane:

[0185] (34)

[0186] (35)

[0187] (36)

[0188] In formulas (34), (35), and (36), is the relative speed between the emergency vehicle and the non-emergency vehicle, is the non-emergency vehicle 's lateral speed, is the total number of non-emergency vehicles on the emergency lane at the step. is the cumulative interference time of the non-emergency vehicle on the emergency vehicle, which is weighted according to the distance between the non-emergency vehicle and the emergency vehicle and the influence intensity of the non-emergency vehicle on the emergency vehicle. When the distance between the emergency vehicle and the nearest non-emergency vehicle in front reaches , the emergency lane is triggered to be cleared. In formula (36), is the influence of the non-emergency vehicle on the emergency vehicle. On the premise that the total lane-changing cost of the non-emergency vehicle is minimized, with the goal of minimizing the influence of the non-emergency vehicle on the emergency vehicle, the smaller the distance between the emergency vehicle and the nearest non-emergency vehicle in front, the less time required to clear the section, the less cumulative interference time of the non-emergency vehicle on the emergency vehicle, and the smaller the influence of the non-emergency vehicle on the emergency vehicle. The minimum value of the influence of the non-emergency vehicle on the emergency vehicle is denoted as

[0189] Step 5: Adopt a joint optimization method for the upper and lower layer objective functions. When the optimal values of the lane-changing cost of the non-emergency vehicle in the upper layer model and the influence on the emergency vehicle in the lower layer model converge and no longer change, terminate the iteration, output the final solution, determine the lane-changing plan of the non-emergency vehicle and the clearing heuristic point, and complete the task of clearing the emergency lane. The specific steps are as follows:

[0190] Step 51: Start from the minimum lane-changing cost of the non-emergency vehicle in the upper layer model to obtain the shortest time-consuming lane-changing trajectory of each non-emergency vehicle, and then gradually iterate through the joint optimization of the upper and lower layer models. After each iteration, check the change trends of the upper layer lane-changing cost and the lower layer influence on the emergency vehicle. If the optimal values of both converge and remain unchanged in multiple consecutive iterations, terminate the iteration.

[0191] Step 52: After the iteration is terminated, output the optimal solutions of the current upper and lower layers, determine the lane-changing plan of the non-emergency vehicle and the clearing heuristic point in each dynamic clearing area, so as to complete the clearing of the entire emergency lane.

[0192] 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.

[0193] 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.

[0194] 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 Figures 3a to 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.

[0195] 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 location of non-emergency vehicles and the expected turning information of turning left, going straight or turning right, an upper-level model for dynamic clearing of the emergency lane is established. The time for all non-emergency vehicles that need to leave the emergency lane to reach the clearing target position is calculated, and the total lane change cost of non-emergency vehicles is formed in combination with the unit cost under the emergency continuous state during the clearing process. The minimum total lane change cost of non-emergency vehicles is taken as the upper-level objective function, and the improved A* algorithm is used to solve it, and the shortest lane change trajectory of each non-emergency vehicle is calculated; Step 4: Under the premise that the total cost of lane change for non-emergency vehicles is minimized, the lower objective function is to minimize the impact of non-emergency vehicles on emergency vehicles. The lower objective function is as follows: In the formula, is the cumulative interference time of non-emergency vehicles on emergency vehicles, is the minimum value of the impact of non-emergency vehicles on emergency vehicles, is the minimum total cost of lane change for non-emergency vehicles, is the relative speed between emergency vehicles and non-emergency vehicles, For the The total number of non-emergency vehicles on the emergency lane, is the cumulative interference time of non-emergency vehicles on emergency vehicles, is the distance between the emergency vehicle and the nearest non-emergency vehicle ahead; 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 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 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, =1 means the ordinate of the initial position of the non-emergency vehicle is equal to the lane number, otherwise =0; 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 minimum time it takes for all non-emergency vehicles that need to leave the emergency lane to reach the cleared target position. The unit time cost of 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 non-emergency vehicles The current position and expected turn of the node, the left node of the current node is considered as an obstacle, and the adjacent extended nodes of the current node are checked. If they are already in the close_list, they are skipped directly; if they are already in the open_list, the current g value is recalculated, 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 formula (34), 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) In the formula, is the relative speed between emergency vehicles and non-emergency vehicles, is the lateral speed of non-emergency vehicles.

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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