Highway platoon division and speed control method based on cloud control platform

Abstract

The embodiment of the application discloses a highway platoon division and speed control method based on a cloud control platform, which comprises the following steps: a roadside device and a networked vehicle report vehicle data; a cloud platform determines each networked vehicle to be platooned on the highway as each target vehicle according to the vehicle data and map data; the cloud platform determines the following mode and platoon strategy of each target vehicle according to the front vehicle type and front vehicle distance of each target vehicle, determines the target speed of each target vehicle according to the following mode of each target vehicle, and sends the target speed to each target vehicle. The embodiment can realize more efficient, safe and flexible highway vehicle platoon management.

Description

Technical Field

[0001] This invention relates to the field of intelligent transportation technology, and in particular to a method for highway platooning and speed control based on a cloud control platform. Background Technology

[0002] With the development of intelligent transportation systems, connected and automated driving technology is gradually becoming an important means of highway traffic management. Existing vehicle-to-vehicle (V2V) communication technology enables vehicles to communicate with each other and achieve platooning. This technology mainly relies on direct communication between vehicles, coordinating vehicle speeds and spacing through real-time information exchange.

[0003] This approach has the following problems:

[0004] Poor communication stability: Vehicle-to-vehicle communication is easily affected by environmental interference, such as weather conditions and building obstructions, resulting in unstable communication signals.

[0005] Insufficient flexibility: Existing vehicle-to-vehicle communication technology is difficult to dynamically adjust and manage platoons, and lacks flexibility.

[0006] High dependence: It relies too much on vehicle-to-vehicle communication. If the communication module of a vehicle fails, the stability and safety of the entire formation will be affected. Summary of the Invention

[0007] This invention provides a method for highway platooning and speed control based on a cloud control platform. By introducing cloud control technology to replace traditional vehicle-to-vehicle communication, it overcomes the problems of unstable communication, delay, and insufficient flexibility in the prior art, and achieves more efficient, safe, and flexible highway vehicle platooning management.

[0008] In a first aspect, embodiments of the present invention provide a method for highway platooning and speed control based on a cloud control platform, including:

[0009] Roadside equipment and connected vehicles report vehicle data;

[0010] Based on the vehicle data and map data, the cloud platform identifies each connected vehicle to be platooned on the highway as a target vehicle.

[0011] The cloud platform determines the following mode and platooning strategy for each target vehicle based on the type of vehicle in front and the distance between vehicles in front. It also determines the target speed for each target vehicle based on the following mode and sends the information to each target vehicle.

[0012] Secondly, embodiments of the present invention provide a highway platooning and speed control system based on a cloud control platform, comprising:

[0013] Roadside equipment and connected vehicles are used to report vehicle data;

[0014] The cloud platform is used to identify each connected vehicle to be platooned on the highway as a target vehicle based on the vehicle data and map data; to determine the following mode and platooning strategy of each target vehicle based on the type of vehicle in front and the distance between vehicles in front; to determine the target speed of each target vehicle based on the following mode; and to send the target speed to each target vehicle.

[0015] In summary, this embodiment of the invention provides a method for highway platooning and speed control based on a cloud control platform, which can achieve the following beneficial effects:

[0016] First, during convoy driving, ensure that each vehicle in the convoy can travel at a predetermined minimum time interval, thereby maintaining the neatness and safety of the formation;

[0017] Secondly, through the coordination of the cloud control platform, the lead vehicle of the current formation and the tail vehicle of the previous formation can travel at the desired longer time interval, thereby avoiding safety hazards and traffic chaos caused by sudden deceleration or acceleration.

[0018] Meanwhile, this embodiment also gives the system greater flexibility, allowing the formation to be dynamically adjusted according to real-time traffic conditions to adapt to different driving needs and environmental changes, thereby improving overall traffic efficiency and safety. Attached Figure Description

[0019] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 This is an architecture diagram of a highway platooning and speed control system based on a cloud control platform provided in an embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram illustrating the data interaction process between a cloud platform and a connected vehicle, provided in an embodiment of the present invention.

[0022] Figure 3 This is a flowchart of a highway platooning and speed control method based on a cloud control platform provided in an embodiment of the present invention. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0024] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0025] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0026] This invention provides a method for highway platooning and speed control based on a cloud control platform. To illustrate this method, a highway platooning and speed control system based on a cloud control platform that supports this method will be introduced first. For example... Figure 1 As shown, the system includes roadside equipment, connected vehicles, and a cloud platform. In this system, vehicles no longer rely on vehicle-to-vehicle communication for information exchange; instead, they are controlled and managed uniformly through the cloud platform. Specifically, the system operation includes the following steps:

[0027] Roadside equipment and vehicle data upload: Roadside sensing equipment senses the surrounding environment and uploads the sensing data to the cloud platform, while connected vehicles report their own vehicle data to the cloud platform.

[0028] Cloud-based data processing and decision-making: The cloud platform receives perception data from each vehicle, performs fusion processing and decision-making, and generates platooning schemes and speed control commands. Optionally, the algorithm is invoked once every 0.2 seconds, meaning that every 0.2 seconds, the cloud obtains the position and speed information of connected vehicles and environmental vehicles on the highway, performs platooning division, and calculates target speeds.

[0029] Command issuance: The cloud platform issues platooning and speed control commands to each vehicle (sending the target speed to each connected vehicle that needs platooning services), guiding it to drive according to the specified plan. Optionally, the issuance frequency is once every 0.2 seconds, meaning a command is issued once every time the algorithm is invoked.

[0030] Figure 2 This demonstrates the data interaction process between the cloud platform and connected vehicles. First, a connected vehicle sends a platooning request to the cloud platform, informing it that it needs to form a platoon and requires a target speed from the cloud (if a platooning request is uploaded, the connected vehicle is treated as a connected vehicle and the target speed is provided; otherwise, it is treated as a non-connected vehicle and no speed is provided). The cloud platform receives this information, analyzes and processes it to formulate appropriate platooning and speed planning strategies. These strategies ensure that vehicles can drive safely and efficiently on highways. Finally, based on the received vehicle operating status information, the cloud platform calculates and sends the target speed value for the next frame. These target speed commands guide vehicles to adjust their speeds, ensuring that all vehicles in the platoon drive in a coordinated manner, achieving the expected platooning effect and driving safety.

[0031] Based on the above systems, Figure 3 This is a flowchart illustrating a highway platooning and speed control method based on a cloud control platform, as provided in an embodiment of the present invention. This method is executed collaboratively by various components of the aforementioned system. For example... Figure 3 As shown, the method specifically includes:

[0032] S110, roadside equipment, and connected vehicles report vehicle data.

[0033] Among them, roadside equipment collects data on all vehicles within its sensing range, including data on connected and non-connected vehicles; connected vehicles report their own vehicle data.

[0034] Optionally, roadside equipment includes roadside sensing devices and roadside units. Roadside sensing devices are installed on both sides of the road to collect raw data on the actual road and traffic environment; this data includes vehicle position, speed, and road conditions, providing the basic information required by the cloud platform. After collection, the roadside units upload the data to the cloud platform.

[0035] S120: Based on the vehicle data and map data, the cloud platform determines each connected vehicle to be platooned on the highway as a target vehicle.

[0036] Combination Figure 1After receiving this data, the cloud platform processes it using data fusion technology (because roadside sensors upload data from all vehicles on the road, and connected vehicles report their own data, so fusion is necessary) to generate comprehensive and accurate environmental perception results. These perception results are compared and integrated with information in the map database (that is, identifying vehicles located on the highway and performing subsequent calculations based on them) to form algorithm inputs, providing support for formation building and speed planning.

[0037] S130 and the cloud platform determine the following mode and formation strategy of each target vehicle based on the type of vehicle in front and the distance between vehicles in front. Based on the following mode of each target vehicle, the platform determines the target speed of each target vehicle and sends it to each target vehicle.

[0038] This step corresponds to Figure 1 The multi-vehicle platooning algorithm described in the text first establishes the platoon, determining the platooning mode for each vehicle (whether it's a following vehicle or a lead vehicle). Then, it performs speed planning, calculating the target speed for each vehicle. Connected vehicles continuously upload their operational status information (such as position and speed) to a cloud platform, ensuring the platform can adjust platooning and speed planning based on the latest data. Finally, the multi-vehicle platooning algorithm calculates the target speed value for each connected vehicle in the next frame and distributes these speed values ​​to each vehicle, guiding them to travel at the planned speed. This process ensures dynamic adjustment of the platoon and speed control, improving the safety and efficiency of highway driving.

[0039] In one specific implementation, the following mode is first determined based on whether the preceding vehicle is a connected vehicle and the distance between the preceding vehicles. Specifically, each target vehicle is traversed in front-to-back order, and the following operations are performed on each target vehicle in turn: The type of the preceding vehicle of the current target vehicle is determined. Based on whether the preceding vehicle is a connected vehicle, the platooning strategy and following mode can be divided into the following two cases:

[0040] Scenario 1: If the vehicle preceding the current target vehicle is a non-connected vehicle, then the current target vehicle will be added to the new platoon, and the following mode will be further subdivided:

[0041] 1) If the distance between the current target vehicle and the vehicle in front is greater than the set distance threshold, then the following mode of the current target vehicle is determined to be speed adjustment mode.

[0042] 2) If the distance between the current target vehicle and the vehicle in front is less than or equal to the set distance threshold, then the following mode of the current target vehicle is determined to be the distance adjustment mode.

[0043] Among them, the distance between the target vehicle and the vehicle in front is the distance between the target vehicle and the vehicle in front.

[0044] Scenario 2: If the vehicle preceding the current target vehicle is a connected vehicle, the decision to add the current target vehicle to the preceding vehicle's platoon and its following mode is determined based on the time distance between the current target vehicle and the preceding vehicle, as well as the length of the preceding vehicle's platoon. The preceding vehicle platoon refers to the platoon of connected vehicles to which the vehicle preceding the current target vehicle belongs. Specifically, depending on the time distance, the platooning strategy and following mode can be divided into the following two cases:

[0045] Scenario A: If the time distance between the current target vehicle and the vehicle in front is greater than the set time distance threshold, the current target vehicle will be added to the new platoon and the following mode of the current target vehicle will be set to speed adjustment mode.

[0046] Scenario B: If the time distance between the current target vehicle and the vehicle in front is less than or equal to the set time distance threshold, then the formation strategy and following mode are further subdivided based on the length of the preceding vehicle convoy:

[0047] 1) If the length of the preceding vehicle formation is less than the maximum formation length, the current target vehicle is added to the preceding vehicle formation, and the following mode of the current target vehicle is set to the queue spacing adjustment mode.

[0048] 2) If the length of the preceding vehicle formation is equal to the maximum formation length, the current target vehicle is taken as the new formation, and the following mode of the current target vehicle is set to the spacing adjustment mode.

[0049] Here is a specific example:

[0050] First, determine whether the vehicle in front is a connected car.

[0051] If the vehicle in front is not a connected vehicle and the distance is greater than 120 meters, the vehicle enters speed adjustment mode; otherwise, it enters spacing adjustment mode.

[0052] If the vehicle in front is a connected vehicle, the decision to join the platoon or maintain the existing mode is based on the following distance and platoon length. Specifically, if the following distance is greater than 3 seconds, the vehicle enters speed adjustment mode and resets the number of vehicles in the preceding vehicle's platoon. If the following distance is less than 3 seconds and the number of vehicles in the platoon is less than the maximum platoon length, the vehicle enters CACC spacing adjustment mode and increases the number of vehicles in the preceding vehicle's platoon. Otherwise, spacing adjustment mode is selected and the number of vehicles in the platoon is reset. The pseudocode logic is as follows:

[0053] / / Confirm following mode

[0054] / / Mode 1: Speed ​​Adjustment Mode

[0055] / / Mode 2: Spacing Adjustment Mode

[0056] / / Mode 3: Queue spacing adjustment mode

[0057] Iterate through each connected vehicle (starting from the connected vehicle at the front):

[0058] Calculate the following distance to the vehicle in front = Distance to the vehicle in front / Speed ​​of the vehicle in front

[0059] If the preceding vehicle type is a non-connected vehicle

[0060] If the distance to the vehicle in front is greater than 120 meters

[0061] Follow mode = Speed ​​adjustment mode

[0062] else

[0063] Follow mode = Spacing adjustment mode

[0064] end if

[0065] Number of vehicles in the formation = 1

[0066] else

[0067] if time interval > 3 seconds

[0068] Follow mode = Speed ​​adjustment mode

[0069] Number of vehicles in the formation = 1

[0070] else

[0071] If the number of vehicles in the formation is less than the maximum formation length (the maximum number of vehicles in the formation).

[0072] Following mode = Queue spacing adjustment mode

[0073] Number of vehicles in a formation = Number of vehicles in a formation + 1

[0074] else

[0075] Follow mode = Spacing adjustment mode

[0076] Number of vehicles in the formation = 1

[0077] end if

[0078] end if

[0079] end if

[0080] Then, based on the following pattern of each target vehicle, determine the acceleration and target speed of each target vehicle. Specifically, traverse each target vehicle in front-to-back order, and perform the following operations on each target vehicle in turn:

[0081] If the current target vehicle's following mode is speed adjustment mode, then the target acceleration of the current target vehicle is calculated based on its free-flow speed and current speed to maintain its free-flow speed when there is no vehicle in front. The free-flow speed refers to the vehicle's maximum speed when there is no vehicle in front, and can be taken as 100 kilometers per hour.

[0082] Optionally, the target acceleration can be calculated using the following formula:

[0083] Target acceleration = k1 × (free flow velocity - current velocity)

[0084] Where k1 is the control parameter, and the other parameters (target acceleration, current speed) refer to the parameters of the current target vehicle.

[0085] If the following mode is the spacing adjustment mode, the target acceleration of the current target vehicle is calculated based on the distance to the vehicle in front, the current speed, and the length of the vehicle in front, so as to achieve a larger time distance when following other vehicles outside the formation.

[0086] Optionally, the target acceleration can be calculated using the following formula:

[0087] Target acceleration = k2 × (distance to the vehicle in front - thw × current speed - length of the vehicle in front) + k3 × (speed of the vehicle in front - current speed)

[0088] Among them, k2 and k3 are control parameters, thw represents the desired time distance, and the other parameters (target acceleration, distance to the vehicle in front, current speed, length of the vehicle in front, speed of the vehicle in front) are parameters of the current target vehicle.

[0089] If the following mode is in the queue spacing adjustment mode, the target acceleration is adjusted through spacing error and speed error feedback to achieve following the vehicle in the queue with a small time interval t1 and a speed close to that of the vehicle in front. Here, "spacing error" and "speed error" refer to the error between the expected and the actual values. Specifically, in an ideal steady state, the current speed is the "speed of the vehicle in front" (with a steady-state acceleration of 0), and the ideal steady-state spacing with the vehicle in front is "the length of the vehicle in front + t1 * the current speed". Therefore, in an ideal steady state, both of these errors are 0.

[0090] Optionally, the target acceleration can be calculated using the following formula:

[0091] Spacing error = (Parachute distance to the vehicle in front - Length of the vehicle in front) - t1 × Current speed

[0092] Speed ​​error = Speed ​​of preceding vehicle - Current speed - t1 × Current acceleration

[0093] Expected speed = Current speed + kp × Spacing error + kd × Speed ​​error

[0094] Target acceleration = (Expected velocity - Current velocity) / Step size

[0095] Where t1 represents the control time constant, kp and kd represent the proportional control coefficient and derivative control coefficient, respectively, and the remaining parameters are those of the current target vehicle. The step size is the time interval between two frames, which is 0.2 seconds (algorithm call frequency).

[0096] After obtaining the target acceleration according to the different situations, the target speed of the current target vehicle is determined based on the target acceleration of the current target.

[0097] Here is a specific example:

[0098] First, define the control parameters k1, k2, k3, thw (desired time interval), kp (proportional control coefficient), kd (derivative control coefficient), and t1 (control time constant).

[0099] Then, iterate through each connected vehicle (starting from the connected vehicle at the front):

[0100] / / Parameter initialization

[0101] k1 = 0.4

[0102] k2 = 0.23

[0103] k3 = 0.07

[0104] thw = 2

[0105] kp = 0.45

[0106] kd = 0.0125

[0107] t1 = 1

[0108] If following mode == speed adjustment mode

[0109] Target acceleration = k1 * (free flow velocity - current velocity)

[0110] else if Following mode == Spacing adjustment mode

[0111] Target acceleration = k2 * (distance to the vehicle in front - thw * current speed - length of the vehicle in front) + k3 * (speed of the vehicle in front - current speed)

[0112] else if Following mode == Queue spacing adjustment mode

[0113] Spacing error = (Distance from the vehicle in front) - (Length of the vehicle in front) - t1 * Current speed

[0114] Speed ​​error = Speed ​​of preceding vehicle - Current speed - t1 * Current acceleration

[0115] Expected speed = Current speed + kp * Spacing error + kd * Speed ​​error

[0116] Target acceleration = (Expected velocity - Current velocity) / Step size

[0117] end if

[0118] Target velocity = max(0, current velocity + step size * target acceleration)

[0119] Target speed = min(maximum speed, target speed)

[0120] The operations described in S110-S130 are performed once per step. When vehicle data changes, the cloud platform determines the new target vehicles in real time based on the new data, determines the following mode and platooning strategy for each new target vehicle, and determines the target speed for each new target vehicle based on the new following mode, and sends it to each new target vehicle, thereby achieving dynamic platooning and speed control.

[0121] In summary, this embodiment provides a method for highway platooning and speed control based on a cloud control platform, which can achieve the following beneficial effects:

[0122] First, during convoy driving, ensure that each vehicle in the convoy can travel at a predetermined minimum time interval, thereby maintaining the neatness and safety of the formation;

[0123] Secondly, through the coordination of the cloud control platform, the lead vehicle of the current formation and the tail vehicle of the previous formation can travel at the desired longer time interval, thereby avoiding safety hazards and traffic chaos caused by sudden deceleration or acceleration.

[0124] Meanwhile, this embodiment also gives the system greater flexibility, allowing the formation to be dynamically adjusted according to real-time traffic conditions to adapt to different driving needs and environmental changes, thereby improving overall traffic efficiency and safety.

[0125] Furthermore, the method of this embodiment also has the following advantages:

[0126] Enhanced communication stability: Unified cloud management avoids common signal interference and delay issues in vehicle-to-vehicle communication, improving communication stability and reliability.

[0127] Fast response speed: The cloud platform has powerful computing capabilities and can process large amounts of data in real time, which significantly improves the system's response speed and decision-making accuracy.

[0128] High flexibility: Formation division and speed control are uniformly coordinated by the cloud platform and can be dynamically adjusted according to real-time traffic conditions, thereby adapting to different driving needs and environmental changes and improving overall traffic efficiency.

[0129] Enhanced security: By reducing reliance on individual vehicle communication modules, the overall security of the system is improved, avoiding platoon stability issues caused by the failure of a single vehicle communication module.

[0130] Large-scale data processing capabilities: The cloud platform can process data from a large number of vehicles and roadside sensing devices, providing more comprehensive environmental perception and more accurate decision support.

[0131] This invention also provides a highway platooning and speed control system based on a cloud control platform. Combined with... Figure 1 The system includes:

[0132] Roadside equipment and connected vehicles are used to report vehicle data;

[0133] The cloud platform is used to identify each connected vehicle to be platooned on the highway as a target vehicle based on the vehicle data and map data; to determine the following mode and platooning strategy of each target vehicle based on the type of vehicle in front and the distance between vehicles in front; to determine the target speed of each target vehicle based on the following mode; and to send the target speed to each target vehicle.

[0134] This embodiment is based on the same inventive concept as any of the above method embodiments, and the limitations in any of the above method embodiments are applicable to this embodiment, and can achieve the same technical effects as any of the above embodiments.

[0135] It should be noted that all data involved in this application are information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of the relevant data must comply with the relevant laws, regulations and standards of the relevant countries and regions, and corresponding operation portals are provided for users to choose to authorize or refuse.

[0136] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the technical solutions of the embodiments of the present invention.

Claims

1. A method for highway platooning and speed control based on a cloud control platform, characterized in that, include: Roadside equipment and connected vehicles report vehicle data; Based on the vehicle data and map data, the cloud platform identifies each connected vehicle to be platooned on the highway as a target vehicle. The cloud platform determines the following mode and platooning strategy for each target vehicle based on the type of vehicle in front and the distance between vehicles in front. It also determines the target speed for each target vehicle based on the following mode and sends the information to each target vehicle.

2. The method according to claim 1, characterized in that, The vehicle data reported by the roadside equipment and connected vehicles includes: Roadside equipment reports data on connected and non-connected vehicles; Connected vehicles report their own vehicle data.

3. The method according to claim 1, characterized in that, The process of determining the following mode and platooning strategy for each target vehicle based on the type of vehicle preceding it and the distance between vehicles preceding it includes: Traverse each target vehicle in front-to-back order and perform the following operations in sequence: If the vehicle in front of the current target vehicle is a non-connected vehicle: the current target vehicle is added to the new platoon; if the distance between the current target vehicle and the vehicle in front is greater than the set distance threshold, the following mode of the current target vehicle is set to speed adjustment mode; if the distance between the current target vehicle and the vehicle in front is less than or equal to the set distance threshold, the following mode of the current target vehicle is set to distance adjustment mode. If the vehicle preceding the current target vehicle is a connected vehicle, the system determines whether to add the current target vehicle to the preceding vehicle's platoon and the following mode of the current target vehicle, based on the time distance between the current target vehicle and the preceding vehicle, as well as the length of the preceding vehicle's platoon.

4. The method according to claim 3, characterized in that, The process of determining whether to add the current target vehicle to the preceding vehicle platoon and the following mode of the current target vehicle based on the time distance between the current target vehicle and the preceding vehicle, as well as the length of the preceding vehicle platoon, includes: If the time distance between the current target vehicle and the vehicle in front is greater than the set time distance threshold, the current target vehicle will be added to the new platoon and the following mode of the current target vehicle will be set to speed adjustment mode. If the time distance between the current target vehicle and the vehicle in front is less than or equal to the set time distance threshold: if the length of the preceding vehicle formation is less than the maximum formation length, the current target vehicle is added to the preceding vehicle formation, and the following mode of the current target vehicle is determined to be the in-queue spacing adjustment mode; if the length of the preceding vehicle formation is equal to the maximum formation length, the current target vehicle is added to the new formation, and the following mode of the current target vehicle is determined to be the spacing adjustment mode.

5. The method according to claim 1, characterized in that, Determining the target speed of each target vehicle based on its following pattern includes: Traverse each target vehicle in front-to-back order and perform the following operations in sequence: If the current target vehicle's following mode is speed adjustment mode, calculate the target acceleration of the current target vehicle based on the free-flow speed and the current speed of the current target vehicle, so as to maintain the free-flow speed when there is no vehicle in front; If the current target vehicle's following mode is the spacing adjustment mode, the target acceleration of the current target vehicle is calculated based on the distance to the vehicle in front, the current speed, and the length of the vehicle in front, so as to achieve following the vehicle outside the formation at a larger time distance; If the current target vehicle's following mode is the queue spacing adjustment mode, the target acceleration of the current target vehicle is adjusted based on the current target vehicle's spacing error and speed error, so as to achieve following the vehicle in the queue at a smaller time distance and at a speed close to that of the vehicle in front. Determine the target speed of the current target vehicle based on its target acceleration.

6. The method according to claim 5, characterized in that, The step of calculating the target acceleration of the current target vehicle based on the free-flow velocity and the current velocity of the current target vehicle includes: Calculate the target acceleration of the current target vehicle using the following formula: Target acceleration = k1 × (free flow velocity – current velocity) Where k1 is the control parameter, and the other parameters are the parameters of the current target vehicle.

7. The method according to claim 5, characterized in that, The step of calculating the target acceleration of the current target vehicle based on the distance to the vehicle in front, the current speed, and the length of the vehicle in front includes: Calculate the target acceleration of the current target vehicle using the following formula: Target acceleration = k2 × (distance to the vehicle in front - thw × current speed - length of the vehicle in front) + k3 × (speed of the vehicle in front - current speed) Among them, k2 and k3 are control parameters, thw represents the desired time distance, and the remaining parameters are parameters of the current target vehicle.

8. The method according to claim 5, characterized in that, The step of adjusting the target acceleration of the current target vehicle based on the distance error and speed error of the current target vehicle includes: The target acceleration of the current target vehicle is adjusted based on the following formula: Spacing error = (Parachute distance to the vehicle in front - Length of the vehicle in front) - t1 × Current speed Speed ​​error = Speed ​​of preceding vehicle - Current speed - t1 × Current acceleration Expected speed = Current speed + kp × Spacing error + kd × Speed ​​error Target acceleration = (Expected velocity - Current velocity) / Step size Where t1 represents the control time constant, kp and kd represent the proportional control coefficient and derivative control coefficient, respectively, and the remaining parameters are the parameters of the current target vehicle. The step size refers to the execution cycle of the entire method.

9. The method according to claim 1, characterized in that, Also includes: When vehicle data changes, the cloud platform determines new target vehicles in real time based on the new data, determines the following mode and platooning strategy for each new target vehicle based on the type of vehicle in front and the distance between vehicles in front, and determines the target speed for each new target vehicle based on the new following mode and sends it to each new target vehicle.

10. A highway platooning and speed control system based on a cloud control platform, characterized in that, include: Roadside equipment and connected vehicles are used to report vehicle data; The cloud platform is used to determine each connected vehicle to be platooned on the highway as a target vehicle based on the vehicle data and map data. Based on the type of vehicle in front and the distance between vehicles in front, determine the following mode and formation strategy for each target vehicle, determine the target speed for each target vehicle based on the following mode, and send the speed down to each target vehicle.

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