Intelligent networked automobile following optimization and collaborative lane changing method for improving safety potential field

Abstract

The invention discloses an intelligent networked vehicle following optimization and cooperative lane changing method for improving a safety potential field, and the method comprises the steps: enabling a vehicle to obtain the information of a target lane and the information of a current lane, and achieving the safety following control of a traffic flow; the vehicle generates a lane changing intention at first, the vehicle calculates and identifies all possible lane changing gaps and safety gaps needed for evaluating lane changing and judges whether the safe lane changing gaps exist or not, if yes, the optimal lane changing gap is selected from the safety gaps, and the vehicle starts to execute lane changing operation; if not, calculating the number of previous lane changing cooperative vehicles of the selectable lane changing gap, selecting the lane changing gap needing the minimum number m of cooperative acceleration vehicles, and establishing an m threshold condition based on the actual situation of the traffic flow; the invention emphasizes safety and cooperation, provides a new improved safety potential field lane changing model based on a traditional safety potential field theory, improves a traditional lane changing control mode, and further realizes safe and efficient car following and lane changing.

Description

[Technical field]

[0001] The present invention belongs to the technical field of intelligent transportation systems, and in particular relates to a method for optimizing car-following and coordinated lane changing of intelligent connected vehicles with an improved safety potential field. [Background technology]

[0002] At present, domestic and foreign scholars have conducted a series of studies on the problems of road vehicle cooperative control, following and lane change coordination, and proposed a variety of research methods. These studies reflect the feasibility and effectiveness of different methods in solving the problem of mixed traffic flow of CAV and HMV. However, the existing technology has deficiencies in the perfection of control strategies, adaptability of models and empirical analysis, especially in high-volume and mixed traffic flow environments. The application effect needs to be improved. In addition, the existing cooperative lane change algorithm is still insufficient in dealing with the uncertainty and complexity of driving behavior, which requires further research and improvement.

[0003] Safety potential field technology is an advanced safety strategy proposed in the field of intelligent transportation systems and autonomous vehicles. It simulates the safe driving path of vehicles in traffic environments and uses mathematical models and algorithms, such as artificial potential field algorithms, fuzzy logic, and reinforcement learning, to dynamically adjust vehicle behavior to ensure safe driving in complex traffic conditions. With the development of autonomous driving technology, vehicles need to process a large amount of data in real time, including their own status information, the location and speed of surrounding vehicles, and road conditions, in order to make fast and accurate decisions. Safety potential field technology not only improves the safety of a single vehicle, but also plays a role in multi-vehicle collaborative control, optimizing the overall traffic flow, reducing congestion, and improving road use efficiency.

[0004] With the rapid development of vehicle-to-everything (V2X) technology, the communication capabilities between vehicles (V2V) and vehicles and infrastructure (V2I) have been significantly enhanced, providing new technical means for vehicle lane-changing decisions. Based on this background, the present invention proposes an intelligent connected car-following optimization and lane-changing method to solve the collision risk, delay, and coordination efficiency problems in the process of vehicle-following and lane-changing, based on the existing intelligent connected car lane-changing model of safety potential field theory. [Summary of the invention]

[0005] In view of the deficiencies in the prior art in the perfection of control strategies, adaptability of models and empirical analysis, especially the application effect in high-volume and mixed traffic flow environments needs to be improved, and the existing cooperative lane-changing algorithms are still insufficient in dealing with the uncertainty and complexity of driving behaviors. The present invention provides a method for intelligent connected vehicle following optimization and cooperative lane changing with an improved safety potential field. Through the coordination of multiple leading vehicles, a good free lane-changing environment is established in the cooperative lane changing, which minimizes the impact on the overall traffic flow, while improving the lane-changing safety, achieving optimal lane changing, and further optimizing the vehicle following safety in the traffic flow.

[0006] A method for optimizing following and coordinated lane changing of intelligent connected vehicles with an improved safety potential field includes the following key contents: the minimum longitudinal safety distance for vehicle lane changing is intended to limit lane changing behaviors with poor safety and improve lane changing safety; the safe following distance is intended to maintain the safe following distance in multi-vehicle following driving and optimize the safety of following driving; the optimal lane changing gap is intended to achieve the lane changing gap selection of connected vehicles during the lane changing process, and further limit lane changing behaviors that have a great impact on safety and traffic flow; the front lane changing method for safe following of intelligent connected vehicles based on the safety potential field is intended to create a free lane changing environment for lane changing vehicles during the lane changing process and achieve the optimal overall traffic flow.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] An intelligent connected vehicle following optimization and coordinated lane changing method with improved safety potential field comprises the following steps:

[0009] S1: During the driving process of vehicles in closed road traffic flow, the system automatically collects real-time traffic information of the target lane and the own lane;

[0010] S2: Traffic flow safety following control based on improved safety potential field, with V2X technology as the core, realizes real-time information exchange between vehicles and the environment through on-board units (OBU) and roadside units (RSU), specifically:

[0011] For the following vehicle flow, add the vehicle L i With the front car L i+1 Safe following distance D safe(i) , defined as the minimum distance a vehicle needs to travel to avoid a collision with the vehicle ahead, taking into account the influence of the safety potential field; this distance is calculated using the following formula:

[0012] D safe(i) =D reaction(i) +D braking(i) +l i +Δl i

[0013] Among them, D reactionis the reaction distance, calculated as:

[0014]

[0015] And D braking is the braking distance, calculated as:

[0016]

[0017] Among them, v i For vehicle L i Speed, α i Vehicle L i acceleration, τ is the critical threshold of safety distance, l i Vehicle L i Length; Δl i is the additional safety distance under the influence of the safety potential field, which is related to the vehicle speed v, acceleration a and safety potential field E v Function of

[0018]

[0019] Among them, ∈ is a small positive constant used to ensure a certain safety distance even in low-risk situations, E v It is expressed as follows:

[0020]

[0021] M i =m i (1.566×10 -14 v 6.687 +0.3345)

[0022]

[0023] Where k′ is the pseudo distance; (x0, y0) is the position coordinate of the target vehicle’s center of mass; θ0 is the angle between a point around the target vehicle and the space coordinate (x0, y0) of the vehicle’s center of mass; m i is the actual mass of the target vehicle i; α is a parameter to be determined related to the speed; φ is the steering angle when the vehicle turns, and the counterclockwise direction of the steering angle is defined as the positive direction of the steering angle; (x * ,y * ) is the original coordinate (x * ,y * ) The corresponding deflection value after turning;

[0024] During the driving of the front and rear vehicles, when the vehicle L i With the front car L i+1 Headway d i Greater than or equal to Dsafe(i) When the vehicle L i With the front car L i+1 Headway d i Less than D safe(i) It is defined as dangerous following, and the system will issue a warning, requiring you to get out of the dangerous following as soon as possible;

[0025] Based on the improved safe following distance model and considering the realization of the overall traffic flow safe following goal, an optimization strategy for the safe following distance under the improved safety potential field is proposed:

[0026] When the vehicle L i With the front car L i+1 When there is dangerous following behavior, let the vehicle L i Slow down or the car in front of you turns L i+1 Accelerate until the vehicle reaches L i With the front car L i+1 Achieve safe following;

[0027] Vehicle L i Slow down, the vehicle L i-1 With the front car L i For safe following, and

[0028] d i-1 -(d i -D safe(i) )>=D safe(i-1)

[0029] Vehicle L i+1 To accelerate, the vehicle L i+1 With the front car L i+2 For safe following, and

[0030] d i+1 -(d i -D safe(i) )>=D safe(i+1)

[0031] where d i-1 For vehicle L i With the following car L i-1 Headway time, d i+1 For vehicle L i+1 With the front car L i+2 Headway, D safe(i-1) For vehicle L i With the following car L i-1 Safe following distance, D safe(i-1) For vehicle L i+1 With the front car L i+2 safe following distance;

[0032] If the vehicle L iWith vehicle L i+1 All meet the conditions for safe following by deceleration or acceleration. Considering the vehicle L i The negative impact of deceleration, give priority to vehicle L i+1 Accelerate to achieve safe following of traffic; when vehicle L i The deceleration condition is not met, so the vehicle L i+1 Accelerate; when the vehicle L i+1 The acceleration condition is not met, so the vehicle L i slow down;

[0033] If the vehicle L i With vehicle L i+1 None of the conditions are met, and vehicle L i-1 With the front car L i For safe following and vehicle L i+1 With the front car L i+2 To follow safely, the vehicle L i Slow down, while vehicle L i+1 Acceleration, need to meet

[0034] (d i -D safe(i) )>=(d i-1 +d i+1 )-(D safe(i-1) +D safe(i+1) )

[0035] If there is a dangerous following behavior that cannot be achieved by accelerating or decelerating the front or rear vehicle, or multiple, consecutive dangerous following behaviors, the system will continuously monitor and warn, and perform vehicle cooperative control when safe following control can be achieved, and give priority to controlling dangerous following behaviors that are lower than the safe following distance;

[0036] Based on the realization of traffic flow safety following control, the road traffic safety and stability are further improved, providing a basis for the lane change gap selection of S4 lane-changing vehicles and the lane change behavior control of S5;

[0037] S3: The vehicle has the intention to change lanes, and the system calculates all possible lane change gaps and the required safety gaps for lane change;

[0038] The vehicle has a lane change intention, and the system calculates all possible lane change gaps and the required safety gap for lane change, specifically:

[0039] The selection of lane-changing gap before a vehicle changes lanes often relies on the driver's experience, which can easily lead to lane-changing failure, low efficiency and collision risk. To address the above problems, based on the traditional safety potential field lane-changing model and considering the optimality principle of gap selection, a selection rule for the minimum longitudinal safety distance and lane-changing gap is proposed:

[0040] Before the vehicle executes the lane change, there are lane change gaps C1, C2, and C3 available in the target lane;

[0041] When there is an intention to change lanes, it is required to keep pace with the vehicle behind in the target lane. h , the front vehicle L in the target lane h+1 , the front vehicle c in the current lane needs to have the following safety distance:

[0042] Vehicle b and the vehicle L behind in the target lane h Minimum longitudinal safety distance between

[0043]

[0044]

[0045] Vehicle b and the front vehicle L in the target lane h+1 Minimum longitudinal safety distance between

[0046]

[0047] The minimum longitudinal safety distance between vehicle b and the vehicle c in front of the current lane

[0048]

[0049] In the above formula, E v represents the safety potential field; T1 represents the safety critical time; the minimum critical distance between workshops under the safety potential field theory G min ; is the width of the vehicle; is the angle between the vehicle and the horizontal direction of the road; a is the acceleration of the target vehicle in its current motion state; v is the current speed of the target vehicle; l is the length of the vehicle; 1 and are all unknown coefficients; M i is the equivalent mass of target vehicle i, is the critical threshold of safety distance;

[0050] S4: realizing the optimal gap selection for lane changing based on the improved safety potential field. If there is a lane changing gap that satisfies the safety gap, go to S7; otherwise, go to S5.

[0051] The implementation of the optimal gap selection for lane change based on the improved safety potential field is specifically as follows:

[0052] When a vehicle intends to change lanes, different gaps have different risks. Based on the lane-changing model with improved safety potential field, the overall low delay and safety of the traffic flow are considered, and it is proposed to classify the lane-changing gaps into "safe", "warning" and "dangerous" and further realize the optimal gap selection.

[0053] A safe lane change gap must meet four conditions at the same time: the target lane change gap is greater than The lane change gap in this lane is greater than There are no vehicles or other obstacles in the expected lane-changing path; the lane-changing vehicle does not need to slow down significantly to change lanes;

[0054] The lane change gap warning must meet three conditions at the same time: there are no vehicles or other obstacles in the expected lane change path; the lane change requires the lane change vehicle to slow down significantly;

[0055] In other cases, it is a dangerous lane-changing gap;

[0056] Safe lane-changing gaps are prioritized, warning lane-changing gaps are second, and dangerous lane-changing gaps are not considered. If all lane-changing gaps are safe or warning, the gap closest to the lane-changing vehicle is selected, i.e., the straight-line distance between the center of the lane-changing gap and the center of mass of the lane-changing vehicle.

[0057] Assume that before the vehicle changes lanes, there are lane change gaps C1, C2, and C3 in the target lane, and all of them satisfy the target lane lane change gaps greater than The lane change gap with the lane is greater than Two conditions;

[0058] (a) Scenario: C1 and C3 lane-changing gaps have vehicles or other obstacles in the expected lane-changing path, which are dangerous lane-changing gaps; C2 lane-changing gaps have no vehicles or other obstacles in the expected lane-changing path, and the lane-changing vehicle does not need to slow down significantly to enter the gap, which is a safe lane-changing gap; C2 lane-changing gap has the highest priority as a safe lane-changing gap, so C2 lane-changing gap is selected;

[0059] (b) Scenario: C1 lane-changing gap has no vehicles or other obstacles on its expected lane-changing path, but the lane-changing vehicle b needs to slow down to position b` to enter the gap, which is a warning lane-changing gap; C2 lane-changing gap has no vehicles or other obstacles on its expected lane-changing path, and the lane-changing vehicle does not need to slow down significantly to enter the gap, which is a safe lane-changing gap; C3 lane-changing gap has vehicles or other obstacles on its expected lane-changing path, which is a dangerous lane-changing gap; C2 lane-changing gap has the highest priority as a safe lane-changing gap, so C2 lane-changing gap is selected;

[0060] (c) Scenario: The lane-changing path of the C1 lane-changing gap is blocked by the vehicle behind the lane, which is a dangerous lane-changing gap. The expected lane-changing paths of the C2 and C3 lane-changing gaps do not have any vehicles or other obstructions, and the lane-changing vehicle does not need to slow down significantly to enter the gap, which is a safe lane-changing gap. Since the C2 lane-changing gap is the closest gap to the lane-changing vehicle, the C2 lane-changing gap is selected.

[0061] (d) Scenario: The expected lane-changing path of the lane-changing gap C1 does not contain any vehicles or other obstacles, and the lane-changing vehicle b needs to slow down to position b` to enter the gap, which is a warning lane-changing gap; the expected lane-changing paths of the lane-changing gaps C2 and C3 do not contain any vehicles or other obstacles, and the lane-changing vehicle does not need to slow down significantly to enter the gap, which is a safe lane-changing gap; since the lane-changing gap C2 is the closest gap to the lane-changing vehicle, the lane-changing gap C2 is selected;

[0062] If there is a safe lane-changing gap, the vehicle starts to change lanes. If not, it proceeds to the next step. Through the FLC collaborative method of intelligent connected vehicles based on the improved safety potential field, a safe lane-changing gap is created to achieve safe lane-changing gaps for lane-changing vehicles.

[0063] S5: FLC collaboration method for intelligent connected vehicles based on improved safety potential field;

[0064] S5-1: Implementing the FLC coordination method based on the safe following distance of traffic flow according to the improved safety potential field, calculating and determining the number of vehicles m that need coordinated acceleration, and setting the m threshold based on the road and traffic conditions; The FLC coordination method based on the safe following distance of traffic flow according to the safety potential field, calculating and determining the number of vehicles m that need coordinated acceleration, and setting the m threshold based on the road and traffic conditions, is specifically:

[0065] Based on the proposed improved safety potential field, safe following control, safe lane changing distance and optimal gap selection, a front lane change (FLC) method for safe following of intelligent connected vehicles is proposed, taking into account the complexity of actual road traffic and the realization of overall low delay. The limit value of the number of cooperative acceleration vehicles m is dynamically set based on the road and traffic conditions.

[0066] The minimum safe lane-changing gap D on the target lane based on the improved safety potential field is calculated as:

[0067]

[0068] If there are m vehicles ahead participating in multi-vehicle coordinated lane change, that is, L h+1 To L h+m The vehicle participates in multi-vehicle coordinated lane change. At t = 0, L h With L h+1 The headway distance is d h (0), L h With L h+m The headway distance is d h (0)+d h+1 (0)...+d h+m (0), in L h With L h+m Under coordinated forward acceleration, L hThe vehicle keeps moving at a constant speed. h With L h+1 When the distance between the front vehicles reaches the minimum safe lane change gap D, the lane change can be performed. The m value must meet the following requirements:

[0069] (d h (0)+d h+1 (0)...+d h+m (0))-(D safe(h) +D safe(h+1) +...+D safe(h+m) )>=D;

[0070] S5-2: The system selects the gap that requires the least coordinated acceleration to change lanes, ensuring that the number of vehicles is minimized. If m meets the set threshold, the system executes the coordinated lane change of multiple leading vehicles. If not, the system terminates the lane change behavior. Specifically:

[0071] Based on the optimal selection of lane-changing gap and FLC cooperative control method under the improved safety potential field, considering the minimum number of cooperation and the minimum overall delay, a gap selection method under FLC control is proposed:

[0072] When there is a lane-changing intention on the road, only the lane-changing gaps behind the left, left, and left front of the lane-changing vehicle, i.e., C1, C2, and C3, are selected; when selecting the lane-changing gap, the number of coordinated vehicles mobilized by C1, C2, and C3 is calculated respectively; it is determined whether it is a safe or warning lane-changing gap. If there is no safe or warning lane-changing gap, the lane-changing gap with the least number of coordinated vehicles is selected. m is the number of coordinated vehicles. When the number of coordinated vehicles is the same, the gap closest to the lane-changing vehicle is selected, i.e., the straight-line distance between the center point of the lane-changing gap and the center of mass of the lane-changing vehicle.

[0073] The system dynamically adjusts the gap selection strategy according to real-time traffic conditions to ensure that the best decision is always made in a changing traffic environment; it shares lane change intentions and required coordinated actions with the coordinated vehicles in real time through V2X communication technology to ensure that all related vehicles can respond synchronously;

[0074] S5-3: Coordinated acceleration is performed based on the safe following distance of the traffic flow of the improved safety potential field to form a gap with a safe lane-changing distance, specifically:

[0075] Assume that the lane-changing vehicle has the lane-changing intention time t = 0. When t = 0, L i With L i+1 The headway distance is d i (0), then L h With L h+1 The original head spacing is d h (0), the distance between the lane-changing vehicle b and the vehicle c in front of it is d b (0); L h ...Lh+m The other vehicles accelerate in coordination to the minimum safe following distance D between each other. safe(i) After that, L h+1 The two vehicles C and B reserve a safe gap for the lane-changing vehicle B. m+1 Total acceleration time of multiple vehicles; after each vehicle accelerates to the minimum safe following distance between two vehicles, it maintains the speed of the convoy;

[0076] The acceleration time t1 of the first controlled vehicle is

[0077] t1=[d h+m (0)-D safe(h+m) (0)] / (a h+m (0))

[0078] Among them, d h+m (0) is the time when the lane-changing vehicle starts changing lanes at t = 0. h+m The distance between the vehicle and the vehicle in front, D safe(h+m) (0) is L when t = 0 h+m With L h+m+1 Minimum safe following distance, a h+m (0) is L when t = 0 h+m acceleration;

[0079] At t = t1, L h+m After the acceleration is completed, the real-time headway distance d of each vehicle in the left lane is retrieved. i (t m ), let L h+m-1 , that is, the car behind the first car starts to accelerate, and the acceleration time of the second car is t2.

[0080] t2=[d h+m-1 (t1)-D safe(h+m-1) (t1)] / (a h+m-1 (t1))

[0081] And so on until L h+1 Vehicle acceleration completed, L h With L h+1 Form a safe lane-changing gap, and finally the total acceleration time of multiple vehicles is t a =t1+t2+...+t m t=t a , you can start changing lanes at this time;

[0082] Among them, the acceleration of the cooperative acceleration vehicle a i is the maximum safe acceleration of vehicle i in the following convoy traffic flow; a i The value of is affected by the performance of the car;

[0083] At t=0, the actual distance between the lane-changing vehicle b and the vehicle c ahead in the lane is d b (0) Whether the safe lane-changing distance is met. If it is met, vehicle C is not controlled and keeps moving at a constant speed during the lane-changing period. If it is not met, the safe lane-changing distance is met between t = 0 and t = t a Complete acceleration, the acceleration distance is

[0084] S6: Lane change execution: When safety conditions are met, the vehicle executes the lane change operation and the traffic flow stability is maintained. During the lane change process, the system ensures the stability of the traffic flow. If the lane change fails due to the driver or other safety hazards, the lane change behavior is terminated;

[0085] S7: Lane change completed.

[0086] In the present invention:

[0087] The closed road described in step S1 specifically refers to expressways, urban expressways, and ordinary roads without intersections within 1 km before and after, where no non-motor vehicles or pedestrians are traveling. Curves, spiral roads, tunnels and ramps where lane changes are prohibited are also excluded.

[0088] Furthermore, the system described in step S1 automatically collects real-time traffic information of the target lane and the own lane, specifically: taking V2X technology as the core, the real-time information exchange between the vehicle and the environment is realized through the on-board unit (OBU) and the roadside unit (RSU).

[0089] Furthermore, the safe following control of traffic based on the improved safety potential field described in step S2 is based on the safe following distance of traffic based on the improved safety potential field, which is of great significance to improving road traffic safety and fluidity, and the concept of the safety potential field is to determine a safe distance by considering the interaction between vehicles to avoid collisions and maintain smooth traffic. The present invention improves the traditional safety potential field that only focuses on the safety of a single vehicle and ignores the safety of the entire traffic flow, and considers the coordinated control of the entire traffic flow under the safe following distance based on the safety potential field, as well as the braking and reaction factors of a single vehicle, and proposes a safe following distance for each vehicle in the following traffic flow and safe following control of the traffic flow.

[0090] Compared with the prior art, the present invention has the following advantages:

[0091] 1. The intelligent connected vehicle following optimization and coordinated lane changing method with improved safety potential field described in the present invention, the front lane change multi-vehicle coordinated lane changing model based on improved safety potential field theory proposed in the present invention aims to significantly improve the lane changing safety and efficiency in traffic environments such as highways and urban expressways. The model reduces the risk of traffic accidents caused by emergency braking or sudden operations by optimizing the safe distance between vehicles, providing drivers with a safer driving experience.

[0092] 2. The method for optimizing the following and coordinated lane changing of intelligent connected vehicles with an improved safety potential field described in the present invention not only improves the driving safety of individual vehicles by optimizing the following and lane changing behaviors of vehicles, but also provides a strong guarantee for the smooth operation of the entire transportation system. The implementation of the present invention also has significant social and economic benefits. By reducing traffic accidents and improving road use efficiency, the economic losses caused by traffic delays can be greatly reduced, while the medical and social costs caused by traffic accidents can be reduced. In terms of the environment, the optimized lane changing model helps to reduce emergency braking and acceleration of vehicles, thereby reducing fuel consumption and emissions, and plays a positive role in environmental protection. In the long run, the technical application of the present invention will promote the development of intelligent transportation systems and make important contributions to the realization of green travel and smart city construction.

[0093] 3. The present invention discloses a method for optimizing following and coordinating lane changes for intelligent connected vehicles with an improved safety potential field. Based on the lane changing model of intelligent connected vehicles in the existing safety potential field theory, the present invention proposes a method for maintaining safe following control of vehicle flow based on a safety potential field, further improving the safe driving of following vehicle flow and providing a real-time quantitative evaluation basis for its safe driving; proposes a method for selecting an optimal gap for lane changing based on a safety potential field, further improving the lane changing efficiency and lane changing safety of vehicles changing lanes; proposes a method for changing lanes before safe following for intelligent connected vehicles based on a safety potential field, reducing overall traffic flow delays and safety hazards caused by active lane changes.

Brief Description of the Drawings

[0094] Figure 1 It is a flow chart of a method for optimizing car-following and coordinated lane-changing for an intelligent connected vehicle with an improved safety potential field according to the present invention;

[0095] Figure 2 It is a flow chart of safe following control of a car flow of an intelligent connected car following optimization and coordinated lane changing method with improved safety potential field according to the present invention;

[0096] Figure 3 It is a schematic diagram of an optimal gap selection scenario of a car-following optimization and coordinated lane-changing method for an intelligent connected vehicle with an improved safety potential field according to the present invention;

[0097] Figure 4 It is a schematic diagram of the vehicle distance related to the lane-changing gap between the host vehicle and the target lane before the lane-changing in the intelligent connected vehicle car-following optimization and coordinated lane-changing method with improved safety potential field described in the present invention;

[0098] Figure 5 It is a flow chart of lane-changing gap selection of a method for optimizing following and coordinating lane changes of an intelligent connected vehicle with an improved safety potential field according to the present invention;

[0099] Figure 6 It is a schematic diagram of a coordinated acceleration scenario of a smart connected vehicle car-following optimization and coordinated lane-changing method with an improved safety potential field according to the present invention;

[0100] Figure 7 It is a flow chart of the FLC collaborative method of the intelligent connected vehicle following optimization and collaborative lane changing method with improved safety potential field described in the present invention. [Specific implementation method]

[0101] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and preferred embodiments. However, it should be noted that many details listed in the specification are only for the purpose of enabling the reader to have a thorough understanding of one or more aspects of the present invention, and these aspects of the present invention can be realized even without these specific details.

[0102] Example:

[0103] like Figure 1 As shown:

[0104] An intelligent connected vehicle following optimization and coordinated lane changing method with improved safety potential field mainly includes the following steps:

[0105] S1: During the driving process of vehicles in closed road traffic flow, the system automatically collects real-time traffic information of the target lane and the own lane;

[0106] S2: Traffic safety following control based on improved safety potential field;

[0107] S3: The vehicle has the intention to change lanes, and the system calculates all possible lane change gaps and the required safety gaps for lane change;

[0108] S4: realizing the optimal gap selection for lane changing based on the improved safety potential field. If there is a lane changing gap that satisfies the safety gap, go to S7; otherwise, go to S5.

[0109] S5: FLC collaboration method for intelligent connected vehicles based on improved safety potential field;

[0110] S5-1: Implement the FLC coordination method based on the traffic safety following distance of the improved safety potential field, calculate and determine the number of vehicles m that need coordinated acceleration, and set the m threshold based on the road and traffic conditions;

[0111] S5-2: The system selects the gap that requires the least coordinated acceleration of the vehicle to change lanes, ensuring that the number of vehicles is minimized. If m meets the set threshold, the system executes the coordinated lane change of multiple vehicles in front. If not, the system terminates the lane change behavior.

[0112] S5-3: Coordinated acceleration based on the safe following distance of the traffic flow of the improved safety potential field to form a gap with a safe lane-changing distance;

[0113] S6: Lane change execution: When safety conditions are met, the vehicle executes the lane change operation and the traffic flow stability is maintained. During the lane change process, the system ensures the stability of the traffic flow. If the lane change fails due to the driver or other safety hazards, the lane change behavior is terminated;

[0114] S7: Lane change completed;

[0115] The closed roads in step S1 specifically refer to expressways, urban expressways, and ordinary roads without intersections within 1 km before and after, where no non-motor vehicles or pedestrians are traveling, and exclude curves, spiral roads, tunnels and ramps where lane changes are prohibited;

[0116] The system of step S1 automatically collects real-time traffic information of the target lane and the own lane, specifically: with V2X technology as the core, the real-time information exchange between the vehicle and the environment is realized through the on-board unit (OBU) and the roadside unit (RSU);

[0117] The safe following control of traffic based on the improved safety potential field in step S2 is specifically as follows: the concept of the safety potential field is to determine a safe distance by considering the interaction force between vehicles to avoid collision and keep traffic smooth; the present invention improves the traditional safety potential field which only focuses on the safety of a single vehicle and ignores the safety of the entire traffic flow, and considers the coordinated control of the entire traffic flow under the safe following distance based on the safety potential field and the braking and reaction factors of a single vehicle, and proposes a safe following distance for each vehicle in the following traffic flow and safe following control of the traffic flow;

[0118] For the following vehicle flow, add the vehicle L i With the front car L i+1 Safe following distance D safe(i) , defined as the minimum distance a vehicle needs to travel to avoid a collision with the vehicle ahead, taking into account the influence of the safety potential field; this distance is calculated using the following formula:

[0119] D safe(i) =D reaction(i) +D braking(i) +l i +Δl i

[0120] Among them, D reaction is the reaction distance, calculated as

[0121]

[0122] And D braking is the braking distance, calculated as

[0123]

[0124] Among them, v i For vehicle L i Speed, α i Vehicle L i acceleration, τ is the critical threshold of safety distance, l i Vehicle L i Length; Δl i is the additional safety distance under the influence of the safety potential field, which is related to the vehicle speed v, acceleration a and safety potential field E v Function of

[0125]

[0126] Among them, E v It is expressed as follows

[0127]

[0128] M i =m i (1.566×10 -14 v 6.687 +0.3345)

[0129]

[0130] Where k′ is the pseudo distance; (x0, y0) is the position coordinate of the target vehicle’s center of mass; θ0 is the angle between a point around the target vehicle and the space coordinate (x0, y0) of the vehicle’s center of mass; m i is the actual mass of the target vehicle i; α is a parameter to be determined related to the speed; φ is the steering angle when the vehicle turns (the counterclockwise direction of the steering angle is the positive direction of the steering angle); (x * ,y * ) is the original coordinate (x * ,y * ) The corresponding deflection value after turning;

[0131] During the driving of the front and rear vehicles, when the vehicle L i With the front car L i+1 Headway d i Greater than or equal to D safe(i) When the vehicle L i With the front car L i+1 Headway d i Less than D safe(i)When the vehicle is in a dangerous following situation, the system will issue a warning and the driver needs to get out of the dangerous following situation as soon as possible. Based on the improved safe following distance model and considering the realization of the overall vehicle flow safe following goal, an optimization strategy for the safe following distance under the improved safety potential field is further proposed.

[0132] When the vehicle L i With the front car L i+1 When there is dangerous following behavior, the vehicle can be L i Slow down or the car in front of you turns L i+1 Accelerate until the vehicle reaches L i With the front car L i+1 Achieve safe following;

[0133] Vehicle L i Slow down, the vehicle L i-1 With the front car L i For safe following, and

[0134] d i-1 -(d i -D safe(i) )>=D safe(i-1)

[0135] Vehicle L i+1 To accelerate, the vehicle L i+1 With the front car L i+2 For safe following, and

[0136] d i+1 -(d i -D safe(i) )>=D safe(i+1)

[0137] where d i-1 For vehicle L i With the following car L i-1 Headway time, d i+1 For vehicle L i+1 With the front car L i+2 Headway, D safe(i-1) For vehicle L i With the following car L i-1 Safe following distance, D safe(i-1) For vehicle L i+1 With the front car L i+2 safe following distance;

[0138] If the vehicle L i With vehicle L i+1 All meet the conditions for safe following by deceleration or acceleration. Considering the vehicle L i The negative impact of deceleration, give priority to vehicle L i+1 Accelerate to achieve safe following of traffic; when vehicle Li The deceleration condition is not met, so the vehicle L i+1 Accelerate; when the vehicle L i+1 The acceleration condition is not met, so the vehicle L i slow down;

[0139] If the vehicle L i With vehicle L i+1 None of the conditions are met, and vehicle L i-1 With the front car L i For safe following and vehicle L i+1 With the front car L i+2 To follow safely, the vehicle L i Slow down, while vehicle L i+1 Acceleration, need to meet

[0140] (d i -D safe(i) )>=(d i-1 +d i+1 )-(D safe(i-1) +D safe(i+1) )

[0141] If there is a dangerous following behavior that cannot be achieved by accelerating or decelerating the front or rear vehicle, or multiple, consecutive dangerous following behaviors, the system will continuously monitor and warn, and perform vehicle cooperative control when safe following control can be achieved, and give priority to controlling dangerous following behaviors that are lower than the safe following distance;

[0142] Traffic flow safety following control, the flow chart is as follows Figure 2 As shown;

[0143] Based on the realization of traffic flow safety following control, the safety and stability of road traffic are further improved, providing a basis for lane change gap selection and lane change behavior control of lane-changing vehicles;

[0144] In step S3, the vehicle generates a lane change intention, and the system calculates all possible lane change gaps and the required safety gaps for lane change, specifically:

[0145] The selection of lane-changing gap before a vehicle changes lanes often relies on the driver's experience, which can easily lead to lane-changing failure, low efficiency and collision risk. To address the above problems, a selection rule for the minimum longitudinal safety distance and lane-changing gap is proposed based on the traditional safety potential field lane-changing model and the optimality principle of gap selection.

[0146] like Figure 3 As shown, before the vehicle executes the lane change, there are lane change gaps C1, C2, and C3 available in the target lane;

[0147] like Figure 4 As shown in the figure, when the lane change intention appears, it is required to h, the front vehicle L in the target lane h+1 , the front vehicle c in the current lane needs to have the following safety distance:

[0148] Vehicle b and the vehicle L behind in the target lane h Minimum longitudinal safety distance between

[0149]

[0150]

[0151] Vehicle b and the front vehicle L in the target lane h+1 Minimum longitudinal safety distance between

[0152]

[0153] The minimum longitudinal safety distance between vehicle b and the vehicle c in front of the current lane

[0154]

[0155] In the above formula, E v represents the safety potential field; T1 represents the safety critical time; the minimum critical distance between workshops under the safety potential field theory G min ; is the width of the vehicle; is the angle between the vehicle and the horizontal direction of the road; a is the acceleration of the target vehicle in its current motion state; v is the current speed of the target vehicle; l is the length of the vehicle; 1 and are all unknown coefficients; M i is the equivalent mass of target vehicle i, is the critical threshold of safety distance;

[0156] The relevant parameter calibration of step S3 is specifically as follows:

[0157]

[0158] The implementation of step S4 is based on the selection of the optimal gap for lane change based on the improved safety potential field, specifically:

[0159] When a vehicle intends to change lanes, different gaps have different risks. Based on the lane-changing model with improved safety potential field, the overall low delay and safety of the traffic flow are considered, and it is proposed to classify the lane-changing gaps into "safe", "warning" and "dangerous" and further realize the optimal gap selection.

[0160] A safe lane change gap must meet four conditions at the same time: the target lane change gap is greater than The lane change gap in this lane is greater than There are no vehicles or other obstacles in the expected lane-changing path; the lane-changing vehicle does not need to slow down significantly to change lanes;

[0161] The lane change gap warning must meet three conditions at the same time: there are no vehicles or other obstacles in the expected lane change path; the lane change requires the lane change vehicle to slow down significantly;

[0162] In other cases, it is a dangerous lane-changing gap;

[0163] Safe lane-changing gaps can be prioritized for lane changing, warning lane-changing gaps have the second priority, and dangerous lane-changing gaps are not considered for lane changing; if all lane-changing gaps are safe or warning, the gap closest to the lane-changing vehicle is selected (i.e., the straight-line distance between the center point of the lane-changing gap and the center of mass of the lane-changing vehicle);

[0164] like Figure 3 As shown, it is assumed that before the vehicle changes lanes, there are lane change gaps C1, C2, and C3 in the target lane, and all of them satisfy the target lane lane change gap greater than The lane change gap with the lane is greater than Two conditions;

[0165] like Figure 3 (a) Scenario: C1 and C3 lane-changing gaps have vehicles or other obstacles in the expected lane-changing path, which are dangerous lane-changing gaps; C2 lane-changing gaps have no vehicles or other obstacles in the expected lane-changing path, and the lane-changing vehicle does not need to slow down significantly to enter the gap, which is a safe lane-changing gap; C2 lane-changing gap has the highest priority as a safe lane-changing gap, so C2 lane-changing gap is selected;

[0166] like Figure 3 (b) Scenario: C1 lane-changing gap has no vehicles or other obstacles on its expected lane-changing path, but the lane-changing vehicle b needs to slow down to position b` to enter the gap, which is a warning lane-changing gap; C2 lane-changing gap has no vehicles or other obstacles on its expected lane-changing path, and the lane-changing vehicle does not need to slow down significantly to enter the gap, which is a safe lane-changing gap; C3 lane-changing gap has vehicles or other obstacles on its expected lane-changing path, which is a dangerous lane-changing gap; C2 lane-changing gap has the highest priority as a safe lane-changing gap, so C2 lane-changing gap is selected;

[0167] like Figure 3 (c) Scenario: The lane-changing path of the C1 lane-changing gap is blocked by the vehicle behind the lane, which is a dangerous lane-changing gap. The expected lane-changing paths of the C2 and C3 lane-changing gaps do not have any vehicles or other obstructions, and the lane-changing vehicle does not need to slow down significantly to enter the gap, which is a safe lane-changing gap. Since the C2 lane-changing gap is the closest gap to the lane-changing vehicle, the C2 lane-changing gap is selected.

[0168] like Figure 3(d) Scenario: The expected lane-changing path of the lane-changing gap C1 does not contain any vehicles or other obstacles, and the lane-changing vehicle b needs to slow down to position b` to enter the gap, which is a warning lane-changing gap; the expected lane-changing paths of the lane-changing gaps C2 and C3 do not contain any vehicles or other obstacles, and the lane-changing vehicle does not need to slow down significantly to enter the gap, which is a safe lane-changing gap; since the lane-changing gap C2 is the closest gap to the lane-changing vehicle, the lane-changing gap C2 is selected;

[0169] Lane change gap selection flow chart Figure 5 As shown;

[0170] If there is a safe lane-changing gap, the vehicle can start to change lanes. If not, it will proceed to the next step. Through the FLC collaborative method of intelligent connected vehicles based on the improved safety potential field, a safe lane-changing gap is created to achieve safe lane-changing gaps for lane-changing vehicles.

[0171] The FLC coordination method based on the safe following distance of the traffic flow in step S5-1 is implemented by calculating and determining the number m of vehicles that need coordinated acceleration, and setting the m threshold based on the road and traffic conditions, specifically:

[0172] Based on the proposed improved safety potential field, the safe following control, safe lane changing distance and optimal gap selection, and considering the complexity of actual road traffic and the realization of overall low delay, an innovative front lane change (FLC) method for safe following of intelligent connected vehicles is proposed, and the limit value of the number of cooperative acceleration vehicles m is dynamically set based on the road and traffic conditions.

[0173] Dynamically set the limit value of the number of cooperative acceleration vehicles m based on road and traffic conditions

[0174] The minimum safe lane-changing gap D on the target lane based on the improved safety potential field is calculated as

[0175]

[0176] If there are m vehicles ahead participating in multi-vehicle coordinated lane change, that is, L h+1 To L h+m The vehicle participates in multi-vehicle coordinated lane change. At t = 0, L h With L h+1 The headway distance is d h (0), L h With L h+m The headway distance is d h (0)+d h+1 (0)...+d h+m (0), in L h With L h+m Under coordinated forward acceleration, L h The vehicle keeps moving at a constant speed.h With L h+1 The distance between the front vehicles reaches the minimum safe lane change gap D, at which time the lane change can be performed, and the m value must meet

[0177] (d h (0)+d h+1 (0)...+d h+m (0))-(D safe(h) +D safe(h+1) +...+D safe(h+m) )>=D

[0178] The greater the average speed of the road traffic flow, the smaller the limit value of the number of cooperative acceleration vehicles m, and the smaller the limit value, the larger the limit value; the greater the traffic density, the smaller the limit value of the number of cooperative acceleration vehicles m, and the greater the traffic density, the smaller the limit value; if the m value is greater than the limit value, the lane change is terminated, otherwise the lane change is executed; wherein, according to the average speed characteristics of the road traffic flow, the traffic speed V is divided into three sets, namely {ordinary road traffic, express road traffic, and high-speed road traffic}, wherein the ordinary road traffic speed is less than 50 kilometers per hour, the express road traffic speed is between 50 and 80 kilometers, and the high-speed road traffic speed is above 80 kilometers; according to the average density characteristics of the road traffic flow, the traffic density K is divided into three sets, namely {low-density road traffic, medium-density road traffic, and high-density road traffic}, wherein low-density road traffic refers to the number of vehicles per kilometer is less than 50, medium-density road traffic is 50 to 100 vehicles per kilometer, and high-density road traffic exceeds 100 vehicles per kilometer;

[0179] The limiting value of m is shown in the following table.

[0180]

[0181]

[0182] The system of step S5-2 selects the gap that requires the least coordinated acceleration vehicle to change lanes, ensuring that the number of vehicles is minimized. If m meets the set threshold, the coordinated lane change of multiple front vehicles is performed. If not, the lane change behavior is terminated. Specifically:

[0183] Based on the optimal selection of lane-changing gap and FLC cooperative control method under improved safety potential field, a gap selection method under FLC control is proposed in order to minimize the overall delay by minimizing the number of cooperative efforts.

[0184] When the lane-changing intention appears on the road, only the lane-changing gaps behind the left, left, and left front of the lane-changing vehicle, i.e., C1, C2, and C3, are selected; when selecting the lane-changing gaps, the number of coordinated vehicles mobilized by C1, C2, and C3 is calculated respectively; it is determined whether it is a safe or warning lane-changing gap. If there is no safe or warning lane-changing gap, the lane-changing gap with the smallest number of coordinated vehicles is selected (m is the number of coordinated vehicles); when the number of coordinated vehicles is the same, the gap closest to the lane-changing vehicle is selected (i.e., the straight-line distance between the center point of the lane-changing gap and the center of mass of the lane-changing vehicle);

[0185] The system will dynamically adjust the gap selection strategy according to the real-time traffic conditions to ensure that the best decision is always made in a changing traffic environment; through V2X communication technology, it will share the lane change intention and the required coordinated actions with the coordinated vehicles in real time to ensure that all related vehicles can respond synchronously;

[0186] The step S5-3 of performing coordinated acceleration based on the safe following distance of the vehicle flow in the safety potential field to form a gap with a safe lane-changing distance is specifically as follows:

[0187] Assume that the lane-changing vehicle has the lane-changing intention time t = 0. When t = 0, L i With L i+1 The headway distance is d i (0), then L h With L h+1 The original head spacing is d h (0), the distance between the lane-changing vehicle b and the vehicle c in front of it is d b (0); L h ...L h+m The other vehicles accelerate in coordination to the minimum safe following distance D between each other. safe(i) After that, L h+1 The two vehicles C and B reserve a safe gap for the lane-changing vehicle B. m+1 Total acceleration time of multiple vehicles; after each vehicle accelerates to the minimum safe following distance between two vehicles, it maintains the speed of the convoy;

[0188] The acceleration time t1 of the first controlled vehicle is

[0189] t1=[d h+m (0)-D safe(h+m) (0)] / (a h+m (0))

[0190] Among them, d h+m (0) is the time when the lane-changing vehicle starts changing lanes at t = 0. h+m The distance between the vehicle and the vehicle in front, D safe(h+m) (0) is L when t = 0 h+m With L h+m+1 Minimum safe following distance, ah+m (0) is L when t = 0 h+m acceleration;

[0191] At t = t1, L h+m After the acceleration is completed, the real-time headway distance d of each vehicle in the left lane is retrieved. i (t m ), let L h+m-1 , that is, the car behind the first car starts to accelerate, and the acceleration time of the second car is t2.

[0192] t2=[d h+m-1 (t1)-D safe(h+m-1) (t1)] / (a h+m-1 (t1))

[0193] And so on until L h+1 Vehicle acceleration completed, L h With L h+1 Form a safe lane-changing gap, and finally the total acceleration time of multiple vehicles is t a =t1+t2+...+t m ; t = t a , you can start changing lanes at this time;

[0194] Among them, the acceleration of the cooperative acceleration vehicle a i is the maximum safe acceleration of vehicle i in the following convoy traffic flow; a i The value of is affected by the performance of the car;

[0195] At t=0, the actual distance between the lane-changing vehicle b and the vehicle c ahead in the lane is d b (0) Whether the safe lane-changing distance is met. If it is met, vehicle C is not controlled and keeps moving at a constant speed during the lane-changing period. If it is not met, the safe lane-changing distance is met between t = 0 and t = t a Complete acceleration, the acceleration distance is

[0196] A flow chart of FLC collaboration method for intelligent connected vehicles based on improved safety potential field is shown in the figure: Figure 7 shown.

[0197] Summary and discussion:

[0198] The present invention proposes a method for optimizing the following and coordinated lane changing of intelligent connected vehicles with improved safety potential fields. In view of the high risk of collision in the following of intelligent connected vehicles and the large delay, poor reliability and low coordination efficiency in lane changing, the existing safety potential field theory has improved the safety of vehicle traffic, but there is still a lack of an effective coordinated control method to achieve safe and effective intelligent connected following and lane changing. Based on the existing safety potential field theory and the lane changing model of intelligent connected vehicles, a vehicle flow safety following control method based on safety potential field and a lane changing optimal gap selection method based on safety potential field are proposed, and finally a front lane change (Front Lane Change, FLC) method for safe following of intelligent connected vehicles based on safety potential field is proposed. The invention includes: the vehicle obtains the target lane information and the lane information to realize the safe following control of the traffic flow; the vehicle first generates the intention to change lanes, the vehicle calculates and identifies all possible lane change gaps and the safety gaps required for evaluating the lane change and determines whether there is a safe lane change gap. If there is, the optimal lane change gap is selected in the safety gap, and the vehicle starts to perform the lane change operation; if there is not, the number of lane change cooperative vehicles in front of the optional lane change gap is calculated, and the lane change gap that requires the least number of cooperative acceleration vehicles m is selected, and the m threshold condition based on the actual traffic flow is established; if m does not exceed the predetermined threshold, the driver or other safety hazards occur during the cooperative acceleration process and the lane change process, the lane change is terminated; the first front vehicle in the target lane starts to accelerate to realize safe following with the front vehicle, and then the second vehicle starts to accelerate until the mth vehicle; after the vehicles accelerate cooperatively, a safe lane change gap is formed, and the lane change starts, and the stability of the traffic flow is maintained during the lane change process. The present invention emphasizes safety and coordination, and is improved based on the traditional safety potential field model to further realize safe and efficient following and lane change.

[0199] The above description is only a preferred embodiment of the present invention. It should be pointed out that it is possible for a person skilled in the art to make several improvements and changes without departing from the creative concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A method for optimizing car-following and coordinated lane-changing for intelligent connected vehicles with improved safety potential field, characterized in that: The following steps are involved: S1: During the driving process of vehicles in closed road traffic flow, the system automatically collects real-time traffic information of the target lane and the own lane; S2: Based on the improved safety potential field, the vehicle flow safety following control is based on V2X technology, and the real-time information exchange between the vehicle and the environment is realized through the on-board unit OBU and the roadside unit RSU. Specifically: For the following vehicle flow, add the vehicle L i With the front car L i+1 Safe following distance D safe(i) , defined as the minimum distance a vehicle needs to travel to avoid a collision with the vehicle ahead, taking into account the influence of the safety potential field; this distance is calculated using the following formula: D safe(i) =D reaction(i) +D braking(i) +l i +Δl i Among them, D reaction is the reaction distance, calculated as: And D braking is the braking distance, calculated as: Among them, v i For vehicle L i Speed, α i Vehicle i acceleration, τ is the critical threshold of safety distance, l i Vehicle L i Length; Δl i is the additional safety distance under the influence of the safety potential field, which is related to the vehicle speed v, acceleration a and safety potential field E v Function of Among them, ∈ is a small positive constant used to ensure a certain safety distance even in low-risk situations, E v It is expressed as follows: M i =m i (1.566×10 -14 in 6.687 +0.3345) Where k′ is the pseudo distance; (x0, y0) is the position coordinate of the target vehicle’s center of mass; θ0 is the angle between a point around the target vehicle and the space coordinate (x0, y0) of the vehicle’s center of mass; m i is the actual mass of the target vehicle i; α is a parameter to be determined related to the speed; φ is the steering angle when the vehicle turns, and the counterclockwise direction of the steering angle is defined as the positive direction of the steering angle; (x * ,y * ) is the original coordinate (x * ,y * ) The corresponding deflection value after turning; During the driving of the front and rear vehicles, when the vehicle L i With the front car L i+1 Headway d i Greater than or equal to D safe(i) When the vehicle L i With the front car L i+1 Headway d i Less than D safe(i) It is defined as dangerous following, and the system will issue a warning, requiring you to get out of the dangerous following as soon as possible; Based on the improved safe following distance model and considering the realization of the overall traffic flow safe following goal, an optimization strategy for the safe following distance under the improved safety potential field is proposed: When the vehicle L i With the front car L i+1 When there is dangerous following behavior, let the vehicle L i Slow down or the car in front of you turns L i+1 Accelerate until the vehicle reaches L i With the front car L i+1 Achieve safe following; Vehicle i Slow down, the vehicle L i-1 With the front car L i For safe following, and d i-1 -(d i -D safe(i) )>=D safe(i-1) Vehicle i+1 To accelerate, the vehicle L i+1 With the front car L i+2 For safe following, and d i+1 -(d i -D safe(i) )>=D safe(i+1) where d i-1 For vehicle L i With the following car L i-1 Headway time, d i+1 For vehicle L i+1 With the front car L i+2 Headway time, D safe(i-1) For vehicle L i With the following car L i-1 Safe following distance, D safe(i-1) For vehicle L i+1 With the front car L i+2 safe following distance; If the vehicle L i With vehicle L i+1 All meet the conditions for safe following by deceleration or acceleration. Considering the vehicle L i The negative impact of deceleration, give priority to vehicle L i+1 Accelerate to achieve safe following of traffic; when vehicle L i The deceleration condition is not met, so the vehicle L i+1 Accelerate; when the vehicle L i+1 The acceleration condition is not met, so the vehicle L i slow down; If the vehicle L i With vehicle L i+1 None of the conditions are met, and vehicle L i-1 With the front car L i For safe following and vehicle L i+1 With the front car L i+2 To follow safely, the vehicle L i Slow down, while vehicle L i+1 Acceleration, need to meet (d i -D safe(i) )>=(d i-1 +d i+1 )-(D safe(i-1) +D safe(i+1) ) If there is a dangerous following behavior that cannot be achieved by accelerating or decelerating the front or rear vehicle, or multiple, consecutive dangerous following behaviors, the system will continuously monitor and warn, and perform vehicle cooperative control when safe following control can be achieved, and give priority to controlling dangerous following behaviors that are lower than the safe following distance; Based on the realization of traffic flow safety following control, the road traffic safety and stability are further improved, providing a basis for the lane change gap selection of S4 lane-changing vehicles and the lane change behavior control of S5; S3: The vehicle has the intention to change lanes, and the system calculates all possible lane change gaps and the required safety gaps for lane change; The vehicle has a lane change intention, and the system calculates all possible lane change gaps and the required safety gap for lane change, specifically: The selection of lane-changing gap before a vehicle changes lanes often relies on the driver's experience, which can easily lead to lane-changing failure, low efficiency and collision risk. To address the above problems, based on the traditional safety potential field lane-changing model and considering the optimality principle of gap selection, a selection rule for the minimum longitudinal safety distance and lane-changing gap is proposed: Before the vehicle executes the lane change, there are lane change gaps C1, C2, and C3 available in the target lane; When there is an intention to change lanes, it is required to keep pace with the vehicle behind in the target lane. h , the front vehicle L in the target lane h+1 , the front vehicle c in the current lane needs to have the following safety distance: Vehicle b and the vehicle L behind in the target lane h Minimum longitudinal safety distance between Vehicle b and the front vehicle L in the target lane h+1 Minimum longitudinal safety distance between The minimum longitudinal safety distance between vehicle b and the vehicle c in front of the current lane In the above formula, E v represents the safety potential field; T1 represents the safety critical time; the minimum critical distance between workshops under the safety potential field theory G min ; is the width of the vehicle; is the angle between the vehicle and the horizontal direction of the road; a is the acceleration of the target vehicle in its current motion state; v is the current speed of the target vehicle; l is the length of the vehicle; 1 and are all unknown coefficients; M i is the equivalent mass of target vehicle i, is the critical threshold of safety distance; S4: realizing the optimal gap selection for lane changing based on the improved safety potential field. If there is a lane changing gap that satisfies the safety gap, go to S7; otherwise, go to S5. The implementation of the optimal gap selection for lane change based on the improved safety potential field is specifically as follows: When a vehicle intends to change lanes, different gaps have different risks. Based on the improved lane-changing model of the safety potential field, the overall low delay and safety of the traffic flow are considered, and it is proposed to classify the lane-changing gaps into "safe", "warning" and "dangerous" and further realize the optimal gap selection. A safe lane change gap must meet four conditions at the same time: the target lane change gap is greater than The lane change gap in this lane is greater than There are no vehicles or other obstacles in the expected lane-changing path; the lane-changing vehicle does not need to slow down significantly to change lanes; The lane change gap warning must meet three conditions at the same time: there are no vehicles or other obstacles in the expected lane change path; the lane change requires the lane change vehicle to slow down significantly; In other cases, it is a dangerous lane-changing gap; Safe lane-changing gaps are prioritized, warning lane-changing gaps are second, and dangerous lane-changing gaps are not considered. If all lane-changing gaps are safe or warning, the gap closest to the lane-changing vehicle is selected, i.e., the straight-line distance between the center of the lane-changing gap and the center of mass of the lane-changing vehicle. Assume that before the vehicle changes lanes, there are lane change gaps C1, C2, and C3 in the target lane, and all of them satisfy the target lane lane change gaps greater than The lane change gap with the lane is greater than Two conditions; (a) Scenario: C1 and C3 lane-changing gaps have vehicles or other obstacles in the expected lane-changing path, which are dangerous lane-changing gaps; C2 lane-changing gaps have no vehicles or other obstacles in the expected lane-changing path, and the lane-changing vehicle does not need to slow down significantly to enter the gap, which is a safe lane-changing gap; C2 lane-changing gap has the highest priority as a safe lane-changing gap, so C2 lane-changing gap is selected; (b) Scenario: C1 lane-changing gap has no vehicles or other obstacles on its expected lane-changing path, but the lane-changing vehicle b needs to slow down to position b` to enter the gap, which is a warning lane-changing gap; C2 lane-changing gap has no vehicles or other obstacles on its expected lane-changing path, and the lane-changing vehicle does not need to slow down significantly to enter the gap, which is a safe lane-changing gap; C3 lane-changing gap has vehicles or other obstacles on its expected lane-changing path, which is a dangerous lane-changing gap; C2 lane-changing gap has the highest priority as a safe lane-changing gap, so C2 lane-changing gap is selected; (c) Scenario: The lane-changing path of the C1 lane-changing gap is blocked by the vehicle behind the lane, which is a dangerous lane-changing gap. The expected lane-changing paths of the C2 and C3 lane-changing gaps do not have any vehicles or other obstructions, and the lane-changing vehicle does not need to slow down significantly to enter the gap, which is a safe lane-changing gap. Since the C2 lane-changing gap is the closest gap to the lane-changing vehicle, the C2 lane-changing gap is selected. (d) Scenario: The expected lane-changing path of the lane-changing gap C1 does not contain any vehicles or other obstacles, and the lane-changing vehicle b needs to slow down to position b` to enter the gap, which is a warning lane-changing gap; the expected lane-changing paths of the lane-changing gaps C2 and C3 do not contain any vehicles or other obstacles, and the lane-changing vehicle does not need to slow down significantly to enter the gap, which is a safe lane-changing gap; since the lane-changing gap C2 is the closest gap to the lane-changing vehicle, the lane-changing gap C2 is selected; If there is a safe lane-changing gap, the vehicle starts to change lanes. If not, it proceeds to the next step. Through the FLC collaborative method of intelligent connected vehicles based on the improved safety potential field, a safe lane-changing gap is created to achieve safe lane-changing gaps for lane-changing vehicles. S5: FLC collaboration method for intelligent connected vehicles based on improved safety potential field; S5-1: Implementing the FLC coordination method based on the safe following distance of traffic flow according to the improved safety potential field, calculating and determining the number of vehicles m that need coordinated acceleration, and setting the m threshold based on the road and traffic conditions; The FLC coordination method based on the safe following distance of traffic flow according to the safety potential field, calculating and determining the number of vehicles m that need coordinated acceleration, and setting the m threshold based on the road and traffic conditions, is specifically: Based on the proposed improved safety potential field for safe following control, safe lane-changing distance, and optimal gap selection, a lane-changing method for safe following of intelligent connected vehicles is proposed, taking into account the complexity of actual road traffic and the realization of overall low delay. The limit value of the number of cooperative acceleration vehicles m is dynamically set based on the road and traffic conditions. The minimum safe lane-changing gap D on the target lane based on the improved safety potential field is calculated as: If there are m vehicles ahead participating in multi-vehicle coordinated lane change, that is, L h+1 To L h+m The vehicle participates in multi-vehicle coordinated lane change. At t = 0, L h With L h+1 The headway distance is d h (0), L h With L h+m The headway distance is d h (0)+d h+1 (0)...+d h+m (0), in L h With L h+m Under coordinated forward acceleration, L h The vehicle keeps moving at a constant speed. h With L h+1 When the distance between the front vehicles reaches the minimum safe lane change gap D, the lane change can be performed. The m value must meet the following requirements: (d h (0)+d h+1 (0)...+d h+m (0))-(D safe(h) +D safe(h+1) +...+D safe(h+m) )>=D; S5-2: The system selects the gap that requires the least coordinated acceleration to change lanes, ensuring that the number of vehicles is minimized. If m meets the set threshold, the system executes the coordinated lane change of multiple leading vehicles. If not, the system terminates the lane change behavior. Specifically: Based on the optimal selection of lane-changing gap and FLC cooperative control method under the improved safety potential field, considering the minimum number of cooperation and the minimum overall delay, a gap selection method under FLC control is proposed: When there is a lane-changing intention on the road, only the lane-changing gaps behind the left, left, and left front of the lane-changing vehicle, i.e., C1, C2, and C3, are selected; when selecting the lane-changing gap, the number of coordinated vehicles mobilized by C1, C2, and C3 is calculated respectively; it is determined whether it is a safe or warning lane-changing gap. If there is no safe or warning lane-changing gap, the lane-changing gap with the least number of coordinated vehicles is selected. m is the number of coordinated vehicles. When the number of coordinated vehicles is the same, the gap closest to the lane-changing vehicle is selected, i.e., the straight-line distance between the center point of the lane-changing gap and the center of mass of the lane-changing vehicle. The system dynamically adjusts the gap selection strategy according to real-time traffic conditions to ensure that the best decision is always made in a changing traffic environment; it shares lane change intentions and required coordinated actions with the coordinated vehicles in real time through V2X communication technology to ensure that all related vehicles can respond synchronously; S5-3: Based on the safe following distance of the traffic flow in the improved safety potential field, coordinated acceleration is performed to form a gap with a safe lane-changing distance. Specifically, the lane-changing vehicle has the lane-changing intention time t=0. When t=0, L i With L i+1 The headway distance is d i (0), then L h With L h+1 The original head spacing is d h (0), the distance between the lane-changing vehicle b and the vehicle c in front of it is d b (0); L h ...L h+m The other vehicles accelerate in coordination to the minimum safe following distance D between each other. safe(i) After that, L h+1 The two vehicles C and B reserve a safe gap for the lane-changing vehicle B. m+1 Total acceleration time of multiple vehicles; after each vehicle accelerates to the minimum safe following distance between two vehicles, it maintains the speed of the convoy; The acceleration time t1 of the first controlled vehicle is t1=[d h+m (0)-D safe(h+m) (0)] / (a h+m (0)) Among them, d h+m (0) is the time when the lane-changing vehicle starts changing lanes at t = 0. h+m The distance between the vehicle and the vehicle in front, D safe(h+m) (0) is L when t = 0 h+m With L h+m+1 Minimum safe following distance, a h+m (0) is L when t = 0 h+m acceleration; At t = t1, L h+m After the acceleration is completed, the real-time headway distance d of each vehicle in the left lane is retrieved. i (t m ), let L h+m-1 , that is, the car behind the first car starts to accelerate, and the acceleration time of the second car is t2. t2=[d h+m-1 (t1)-D safe(h+m-1) (t1)] / (a h+m-1 (t1)) And so on until L h+1 Vehicle acceleration completed, L h With L h+1 Form a safe lane-changing gap, and finally the total acceleration time of multiple vehicles is t a =t1+t2+...+t m t=t a , you can start changing lanes at this time; Among them, the acceleration a of the cooperative acceleration vehicle i is the maximum safe acceleration of vehicle i in the following convoy traffic flow; a i The value of is affected by the performance of the car; At t=0, the actual distance between the lane-changing vehicle b and the vehicle c ahead in the lane is d b (0) Whether the safe lane-changing distance is met. If it is met, vehicle C is not controlled and keeps moving at a constant speed during the lane-changing period. If it is not met, the safe lane-changing distance is met between t = 0 and t = t a Complete acceleration, the acceleration distance is S6: Lane change execution: When safety conditions are met, the vehicle executes the lane change operation and the traffic flow stability is maintained. During the lane change process, the system ensures the stability of the traffic flow. If the lane change fails due to the driver or other safety hazards, the lane change behavior is terminated; S7: Lane change completed.

2. The method for optimizing car-following and coordinated lane-changing for an intelligent connected vehicle with improved safety potential field according to claim 1, characterized in that: The closed road described in step S1 specifically refers to expressways, urban expressways, and ordinary roads without intersections within 1 km before and after, where no non-motor vehicles or pedestrians are traveling. Curves, spiral roads, tunnels and ramps where lane changes are prohibited are also excluded.

3. The method for optimizing car-following and coordinated lane-changing for intelligent connected vehicles with improved safety potential field according to claim 1, characterized in that: Furthermore, the system described in step S1 automatically collects real-time traffic information of the target lane and the own lane, specifically: taking V2X technology as the core, the real-time information exchange between the vehicle and the environment is realized through the on-board unit OBU and the roadside unit RSU.

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