Truck formation-based car following control method and car following control system

Abstract

The invention provides a vehicle following control method and system based on a truck formation, and the method comprises the following steps: enabling the following vehicles in the truck formation to run in a formation driving mode when the wireless communication connection is detected to be normal, adjusting the speed of the following vehicles, and enabling the following vehicles to run in a formation driving mode when the wireless communication connection is detected to be normal; enabling the following vehicle to follow the front vehicle to run at a first target vehicle speed which is basically the same as that of the front vehicle, and enabling the following vehicle and the front vehicle to basically keep a first target following distance; when it is detected that the wireless communication connection is abnormal, the following vehicle is made to run in a formation adjusting mode, the speed of the following vehicle is adjusted to increase the distance between the following vehicle and the front vehicle, the following vehicle is made to run along with the front vehicle at a second target following distance, and the second target following distance is larger than the first target following distance. According to the vehicle following control method, the vehicle following distance of each vehicle in the truck formation can be coordinated, the driving safety of the truck formation is improved, and the following vehicles can continue to run in the truck formation as much as possible.

Description

Technical Field

[0001] The present invention relates to the field of advanced driver assistance for truck platoons, and in particular to a vehicle following control method and a vehicle following control system based on truck platoons. Background Art

[0002] In recent years, with the widespread application of ADAS technology in the truck field and the continuous development of V2V communication and V2X communication, truck platooning has emerged. Truck platooning means that two or more trucks can form a platoon to improve road traffic efficiency, driving safety and economic efficiency. In a truck platoon, any two trucks can communicate with each other via V2V to obtain each other's speed, acceleration and other driving information, and each truck is equipped with an independent GPS device to obtain its own location and other information. For the entire truck platoon, a control system can be set up, which can coordinate and control by comprehensively considering the above information, so that each truck can respond quickly and automatically, so as to maintain the truck platoon while driving safely and stably.

[0003] However, when a truck convoy is traveling in a tunnel or passing between high-rise buildings, the wireless communication connection of the trucks may be interfered with (for example, the V2V signal and GPS signal are weak). Therefore, the following vehicle cannot receive acceleration feedback and braking feedback signals from the leading vehicle, resulting in the following vehicle being unable to take timely measures to ensure a safe distance between vehicles, thereby causing a rear-end collision.

[0004] Prior art, such as CN114616154, proposes a control method for adjusting the following distance between vehicles based on whether the V2X connection is normal and the driver's reaction time. However, the prior art does not mention the specific control method of the following vehicle in the platoon driving mode when the wireless communication connection is normal, nor does it mention the specific control method of the following vehicle during the recovery of the wireless communication connection. Summary of the invention

[0005] In view of the above problems, the present invention proposes a following vehicle control method and a following vehicle control system based on a truck platoon, which can take into account the wireless connection status of the vehicle platoon and perform real-time control of the following vehicles in the truck platoon. This not only coordinates the following distance of the following vehicles to improve the driving safety of the truck platoon, but also can keep the following vehicles in platoon driving as much as possible.

[0006] According to a first aspect of the present invention, a following vehicle control method based on a truck platoon is provided, wherein the truck platoon includes a lead vehicle and at least one following vehicle following the lead vehicle, wherein the following vehicle control method includes the following steps: for each following vehicle, when it is detected that the wireless communication connection is normal, the following vehicle is caused to travel in a platoon driving mode, and in the platoon driving mode, the speed of the following vehicle is adjusted so that the following vehicle follows the leading vehicle at a first target speed substantially the same as that of the leading vehicle, so that a first target following distance is substantially maintained between the following vehicle and the leading vehicle; and when an abnormal wireless communication connection is detected, the following vehicle is caused to travel in a platoon adjustment mode, and in the platoon adjustment mode, the speed of the following vehicle is adjusted to increase the distance between the following vehicle and the leading vehicle, so that the following vehicle follows the leading vehicle at a second target following distance, and the second target following distance is greater than the first target following distance.

[0007] According to one embodiment of the present invention, the step of adjusting the speed of the following vehicle in the formation driving mode includes: obtaining the accelerator pedal opening and brake pedal opening of the leading vehicle; calculating the first target acceleration of the following vehicle by linear quadratic adjustment control based on the following vehicle driving information, the leading vehicle driving information and the actual following distance between the following vehicle and the leading vehicle; calculating the target accelerator pedal opening of the following vehicle based on the accelerator pedal opening of the leading vehicle and the first target acceleration of the following vehicle, or calculating the target brake pedal opening of the following vehicle based on the brake pedal opening of the leading vehicle and the first target acceleration of the following vehicle, and when calculating the target brake pedal opening of the following vehicle, the first target acceleration of the following vehicle is less than 0; and adjusting the speed of the following vehicle based on the target accelerator pedal opening or the target brake pedal opening of the following vehicle, so that the following vehicle and the leading vehicle have substantially the same first target speed.

[0008] According to one embodiment of the present invention, the step of adjusting the speed of the following vehicle in the formation adjustment mode includes: reducing the speed of the following vehicle so that the distance between the following vehicle and the leading vehicle increases by half of a first adjustment distance; and after the distance between the following vehicle and the leading vehicle increases by half of the first adjustment distance, gradually increasing the speed of the following vehicle to be consistent with the speed of the leading vehicle so that the distance between the following vehicle and the leading vehicle increases again by half of the first adjustment distance, until the distance between the following vehicle and the leading vehicle is the second target following distance, and the following vehicle will then continue to follow the leading vehicle at the second target following distance.

[0009] According to one embodiment of the present invention, the step of adjusting the speed of the following vehicle in the formation adjustment mode includes: determining the first adjustment distance to be increased between the following vehicle and the leading vehicle based on the current speed of the head vehicle of the truck formation; calculating the second target speed of the following vehicle in the formation adjustment mode based on the first adjustment distance; adjusting the speed of the following vehicle to reduce it to the second target speed, so that the distance between the following vehicle and the leading vehicle is increased by half of the first adjustment distance.

[0010] According to one embodiment of the present invention, the step of adjusting the speed of the following vehicle in the formation adjustment mode also includes: after the speed of the following vehicle decreases to the second target speed, gradually increasing the speed of the following vehicle to the stable driving speed of the following vehicle when maintaining the truck formation driving, so that the distance between the following vehicle and the leading vehicle is increased again by half of the first adjustment distance, until the following vehicle is separated from the leading vehicle by the second target following distance, wherein the stable driving speed is equal to the first target speed.

[0011] According to one embodiment of the present invention, the step of adjusting the speed of the following vehicle in the formation adjustment mode also includes: calculating the second target acceleration of the following vehicle by using PID control based on the second target speed of the following vehicle; obtaining the third target acceleration of the following vehicle by using linear quadratic adjustment based on the following vehicle driving information, the leading vehicle driving information and the actual following distance between the following vehicle and the leading vehicle; comparing the second target acceleration of the following vehicle with the third target acceleration of the following vehicle, and reducing the speed of the following vehicle by using the smaller of the second target acceleration and the third target acceleration.

[0012] According to one embodiment of the present invention, the step of adjusting the speed of the following vehicle in the formation adjustment mode also includes: when the difference between the third target acceleration and the second target acceleration is less than a preset value, causing the following vehicle to enter a formation disbanding mode to leave the truck formation.

[0013] According to one embodiment of the present invention, in the formation adjustment mode, after the speed of the following vehicle decreases to the second target speed, if an abnormality in the wireless communication connection is detected for a predetermined period of time, the following vehicle is caused to enter a formation disbanding mode to leave the truck formation.

[0014] According to one embodiment of the present invention, the following vehicle control method also includes the following steps: during the period when the following vehicle is traveling in the formation adjustment mode, if it is detected that the wireless communication connection has returned to normal, the following vehicle is caused to travel in the formation recovery mode, and in the formation recovery mode, the speed of the following vehicle is adjusted to reduce the distance between the following vehicle and the leading vehicle, so that the following vehicle follows the leading vehicle at a third target following distance, and the third target following distance is smaller than the second target following distance.

[0015] According to one embodiment of the present invention, the step of adjusting the speed of the following vehicle in the formation recovery mode includes: increasing the speed of the following vehicle so that the distance between the following vehicle and the leading vehicle is reduced by half of a second adjustment distance; and after the distance between the following vehicle and the leading vehicle is reduced by half of the second adjustment distance, gradually reducing the speed of the following vehicle to the stable driving speed of the formation driving mode, so that the distance between the following vehicle and the leading vehicle is reduced by half of the second adjustment distance again, until the following vehicle and the leading vehicle are separated by the third target following distance, and the following vehicle will then continue to follow the leading vehicle at the third target following distance.

[0016] According to one embodiment of the present invention, the step of adjusting the speed of the following vehicle in the formation recovery mode includes: determining the second adjustment distance to be reduced between the following vehicle and the leading vehicle based on the current speed of the head vehicle of the truck formation; calculating the third target speed of the following vehicle in the formation adjustment mode based on the second adjustment distance; adjusting the speed of the following vehicle to increase it to the third target speed, so that the distance between the following vehicle and the leading vehicle is reduced by half of the second adjustment distance.

[0017] According to one embodiment of the present invention, the step of adjusting the speed of the following vehicle in the formation recovery mode includes: after the speed of the following vehicle increases to the third target speed, gradually reducing the speed of the following vehicle to the stable driving speed of the following vehicle when maintaining the truck formation driving, so that the distance between the following vehicle and the leading vehicle is reduced again by half of the second adjustment distance, until the distance between the following vehicle and the leading vehicle is the third target following distance, wherein the stable driving speed is equal to the first target speed.

[0018] According to one embodiment of the present invention, the step of adjusting the speed of the following vehicle in the formation recovery mode also includes: based on the third target speed of the following vehicle, using PID control to calculate the fourth target acceleration of the following vehicle; based on the following vehicle driving information, the leading vehicle driving information and the actual following distance between the following vehicle and the leading vehicle, using linear quadratic adjustment to obtain the fifth target acceleration of the following vehicle; comparing the fourth target acceleration of the following vehicle with the fifth target acceleration of the following vehicle, and using the smaller of the fourth target acceleration and the fifth target acceleration to increase the speed of the following vehicle.

[0019] According to one embodiment of the present invention, the step of adjusting the speed of the following vehicle in the formation recovery mode further includes: when the actual speed of the following vehicle recovers to the stable driving speed, causing the following vehicle to travel in the formation driving mode.

[0020] According to a second aspect, a vehicle following control method capable of executing any of the vehicle following control methods described above is provided.

[0021] According to the above-mentioned following vehicle control method and following vehicle control system of the present invention, even when the wireless communication connection of the truck is abnormal, the vehicle speed can be continuously adjusted. Therefore, it is possible to coordinate the following distance between the following vehicle and the leading vehicle to improve the driving safety of the truck formation while trying to keep the following vehicle in the truck formation. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The features, advantages and technical effects of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which:

[0023] Figure 1 A simplified diagram of a truck including a vehicle following control system according to an embodiment of the present invention is shown;

[0024] Figure 2 The control mode implemented by the vehicle following control system according to the embodiment of the present invention is shown. DETAILED DESCRIPTION

[0025] The following is a further detailed description of the embodiments of the present invention in conjunction with the accompanying drawings and examples, wherein the same or similar components in the drawings are indicated by the same reference numerals. The detailed description of the following embodiments and the accompanying drawings are used to illustrate the principles of the present invention by way of example, but are not intended to limit the scope of the present invention, i.e., the present invention is not limited to the described embodiments.

[0026] The following vehicle control system according to the embodiment of the present invention can be applied to a truck formation. The truck formation can include n trucks, wherein the n trucks are 1 lead truck and n-1 follower trucks, and the n-1 follower trucks can follow the lead truck in sequence, where n can be greater than 2. The following vehicle control system according to the present invention can control each follower truck in the truck formation, thereby not only coordinating the following distance of the follower truck to improve the driving safety of the truck formation, but also making the follower truck keep driving in formation as much as possible. Figure 1 Schematic diagram showing a truck equipped with a vehicle following control system according to an embodiment of the present invention. Figure 1 As shown, the truck includes a detection device, a navigation device, a communication device, a vehicle following control system, etc.

[0027] The detection device may include a camera, a radar, a laser detector, an ultrasonic detector, etc. The detection device may be installed in front of the truck, at the rear, on the side and / or at other locations suitable for detecting the environment around the truck. When an abnormality occurs in the wireless connection of the communication device described later, the detection device may obtain the driving information of other trucks (such as the leading vehicle) in the truck formation through any of the above detection units and / or a combination of several detection units. The driving information includes, but is not limited to: the actual distance between the following vehicle and the leading vehicle, lane line information, etc.

[0028] The navigation device can receive satellite signals indicating the location at a specific time point, and periodically receive updated location information, thereby being able to obtain the location of the following vehicle, thereby calculating other driving information of the following vehicle, such as speed and acceleration, etc. In addition, the navigation device can plan a navigation route for the following vehicle based on map data.

[0029] The communication device can obtain driving information of other trucks in the truck formation, such as the leading vehicle, through V2V communication or V2X communication, including but not limited to the position, speed, acceleration, accelerator pedal opening, brake pedal opening, etc. of the leading vehicle. The leading vehicle referred to in this article only refers to the leading truck located in front of and adjacent to the following vehicle.

[0030] The vehicle following control system can communicate with the detection device, the navigation device and the communication device via the truck bus. The vehicle following control system includes: one or more receivers; one or more memories; one or more processors; one or more programs, the receiver is used to obtain relevant information, the program is stored in the memory, and the processor executes one or more programs to implement the vehicle following control method described later.

[0031] The receiver is configured to receive the driving information of other trucks in the truck formation and the driving information of the following vehicle via wireless communication and / or wired communication, and provide this information to the processor. The memory, as a non-transient computer-readable storage medium, can be used to store non-transient software programs, non-transient computer executable programs and signals, such as program instructions / signals corresponding to the vehicle following control system in the embodiment of the present application. The processor runs the non-transient software programs, instructions and signals stored in the memory by combining the information provided by the processor, thereby executing various functional applications and data processing, that is, implementing the vehicle following control method of the above method embodiment. The memory may include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required for at least one function; the data storage area may store relevant data of the above vehicle following control method, such as the numbering information of the vehicle formation, etc. In addition, the memory may include a high-speed random access memory, and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage device. In some embodiments, the memory may optionally include a memory remotely arranged relative to the processor, and these remote memories may be connected to the vehicle following control system via a network. Examples of the above network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network and a combination thereof. The receiver, memory and processor may communicate with each other to transfer relevant data, instructions and signals therebetween.

[0032] Refer to the following Figure 2 The following vehicle control method according to an embodiment of the present invention is described. During the entire following vehicle control period, it is necessary to continuously detect whether the wireless communication connection is normal, and then change different control strategies based on the detection results to adjust the speed of the following vehicle, thereby coordinating the following distance between the following vehicle and the leading vehicle to improve the driving safety of the truck platoon.

[0033] When it is detected that the wireless communication connection is normal, the following vehicle is driven in a platoon driving mode. In the platoon driving mode, the speed of the following vehicle is adjusted so that the following vehicle follows the leading vehicle at the same first target speed as the leading vehicle, so that the first target following distance is maintained between the following vehicle and the leading vehicle.

[0034] The adjustment of the speed of the following vehicle in the platoon driving mode includes the following steps:

[0035] S11: Acquire the accelerator pedal opening and brake pedal opening of the leading vehicle. Since the wireless communication connection of the following vehicle is normal in the platoon driving mode, the accelerator pedal opening and brake pedal opening of the leading vehicle can be obtained smoothly. Of course, the actual acceleration / deceleration of the leading vehicle can also be obtained.

[0036] S12: Based on the following vehicle driving information, the front vehicle driving information and the actual following distance between the following vehicle and the front vehicle, a first target acceleration of the following vehicle is obtained. Specifically, the speed of the front vehicle, the speed of the following vehicle, the acceleration of the following vehicle and the actual following distance between the front vehicle and the following vehicle can be obtained from the detection device and the navigation device, and the first target acceleration of the following vehicle can be calculated by linear quadratic regulation control, wherein the specific steps of the linear quadratic regulation control are as follows:

[0037] 121) List the state vectors x and u related to the linear quadratic regulation control, where x is related to the driving information of the following vehicle, the driving information of the leading vehicle, and the following distance between the following vehicle and the leading vehicle, and u is the first target acceleration.

[0038]

[0039] Among them, Δd is the distance deviation between the leading vehicle and the following vehicle, ΔV is the speed deviation between the leading vehicle and the following vehicle, and a is the acceleration of the following vehicle.

[0040] 122) Δd = d(t) - d ref (t), d ref (t) = T h V ego Substituting (t)+d0 into the above expression (11), we can obtain the following system state equation about x(t):

[0041]

[0042] Where d(t) is the actual distance between the leading vehicle and the following vehicle, d ref (t) is the expected distance between the leading vehicle and the following vehicle, and the expected distance between the leading vehicle and the following vehicle is d ref (t) is calculated by empirical formula, T h is the time coefficient, i.e., the following distance, which can be preset as a constant value; V ego (t) is the actual speed of the following vehicle, d0 is the reserved safety distance between the two vehicles, which is usually a preset empirical parameter; V(t) is equal to ΔV, which represents the difference between the actual speed of the leading vehicle and the actual speed of the following vehicle.

[0043] 123) Taking the derivative of the above expression (12), we can get The system state equation is:

[0044]

[0045] 124) Simplifying the above expression (13), we can further obtain The system state space model is:

[0046]

[0047] in, u(t)=a ref (t)

[0048] 125) Solve the Riccati equation to obtain the feedback matrix K, and then use the following expression (15) to calculate the first target acceleration of the following vehicle.

[0049]

[0050] As can be seen from the above expression (15), the first target acceleration of the following vehicle is related to the following distance difference between the following vehicle and the leading vehicle, the relative speed difference between the following vehicle and the leading vehicle, and the acceleration of the following vehicle.

[0051] S13: Based on the first target acceleration of the following vehicle and the accelerator pedal opening of the leading vehicle, the target accelerator pedal opening of the following vehicle can be obtained, or based on the first target acceleration of the following vehicle and the brake pedal opening of the leading vehicle, the target brake pedal opening of the following vehicle can be obtained. When calculating the target brake pedal opening of the following vehicle, the first target acceleration is less than 0.

[0052] S14: The speed of the following vehicle can be adjusted by using the target accelerator pedal opening or the target brake pedal opening of the following vehicle, so that the following vehicle has a first target speed substantially the same as that of the leading vehicle, so that the following vehicle and the leading vehicle travel substantially at a first target following distance. The first target following distance can be determined according to the numerical value of the first target speed. If the first following vehicle is larger, the first target following distance should also be larger to prevent the following vehicle from colliding with the leading vehicle due to a longer driver reaction time or a longer braking distance.

[0053] When an abnormality in the wireless communication connection is detected, the following vehicle is caused to travel in a platoon adjustment mode. In the platoon adjustment mode, the speed of the following vehicle is adjusted to increase the distance between the following vehicle and the leading vehicle, so that the following vehicle follows the leading vehicle at a second target following distance, and the second target following distance is greater than the first target following distance. The abnormality in the wireless communication connection here includes but is not limited to weak V2V signals between trucks, weak GPS signals of each truck itself, etc.

[0054] In the formation adjustment mode, due to the abnormal wireless communication connection of the following vehicle, the following vehicle cannot obtain the accelerator pedal opening and brake pedal opening of the leading vehicle in time, and thus cannot adjust the speed of the following vehicle according to the accelerator pedal opening and brake pedal opening of the leading vehicle as in the formation driving mode. In this case, in order to ensure the safe driving of the entire truck formation, it is necessary to adjust the speed of each truck in the truck formation to increase the distance between any two adjacent vehicles in front and behind. Therefore, for each following vehicle, it is necessary to first reduce the speed of the rear vehicle to increase the distance between the rear vehicle and the leading vehicle, and then after the speed of the rear vehicle increases to the second target speed, it is necessary to increase the speed of the rear vehicle to further increase the distance between the rear vehicle and the leading vehicle, until the rear vehicle and the leading vehicle are separated by the second target following distance. The control of the speed of the following vehicle in the formation adjustment mode will be described in detail below.

[0055] The steps for adjusting the speed of the following vehicle in the platoon adjustment mode include:

[0056] S21: determining a first adjustment distance to be increased between the following vehicle and the leading vehicle based on the current speed of the leading vehicle of the truck formation, and then calculating a second target speed of the following vehicle in the formation adjustment mode based on the first adjustment distance. The second target speed may be, for example, less than the first target speed. The specific calculation steps of the second target speed are as follows:

[0057] 211) Obtain the stable driving speed V of the following vehicle when maintaining the truck platoon i_fix , where i represents the number of the following vehicle in the truck formation;

[0058] 212) Preset the first adjustment distance d to be increased between the following vehicle and the preceding vehicle adjust , the minimum driving speed V in the truck platoon min Among them, the first adjustment distance d adjust It is related to the current speed of the leading vehicle in the truck formation. If the current speed of the leading vehicle in the truck formation is 120 km / h, the first adjustment interval d adjust For example, if the current speed of the leading vehicle in the truck formation is 100 km / h, the first adjustment distance d can be set to 20 m. adjust For example, the first adjustment distance d can be set to 10m. If the current speed of the leading vehicle in the truck formation is 60km / h, the first adjustment distance d can be set to adjust For example, it is set to 5m, that is, the value of the first adjustment interval increases with the increase of the current speed of the head vehicle of the truck formation, and decreases with the decrease of the current speed of the head vehicle of the truck formation. minis the minimum speed of the last vehicle in the truck platoon, which is related to the length of the truck platoon (i.e., the number of trucks in the truck platoon). For example, when the truck platoon is traveling at a speed of 90 km / h, if the truck platoon consists of only two trucks, i.e., a leading vehicle and a following vehicle, then the minimum speed V in the truck platoon is min is the minimum speed of the following vehicle, which can be preset to 80 km / h; if the truck formation includes four trucks, namely one leading truck and three following trucks, then the minimum driving speed V in the truck formation is min is the minimum speed of the last following vehicle, which can be preset to 60 km / h. Then, the adjustment time t required for the entire truck formation to complete speed adjustment can be calculated according to the following expression (21): ad j ust ;

[0059]

[0060] Where n is the total number of trucks in the truck platoon.

[0061] 213) Calculate the speed difference V that the following vehicle needs to reduce according to the following expression (22): dec_i :

[0062]

[0063] 214) Calculate the second target vehicle speed V of the following vehicle in the platoon adjustment mode according to the following expression (23): target_i :

[0064]

[0065] Among them, t counter =t adjust ×j sum , j sum is a function of j, where j is the calculation period, i.e., the number of calculations. When the calculation period increases once, j increases by 1 accordingly; and when the adjustment calculation begins, j increases from 1. When j <= 0.5*t adjust When sum =j; when j>0.5*t adjust When j changes from 0.5*t adjust Start to decrease, j sum =j-1; when j=t adjust When sum = 0, at this time j can stop increasing, and the second target vehicle speed V is calculated at this time target_i .

[0066] S22: After calculating the second target speed of the following vehicle in the platoon adjustment mode, adjust the speed of the following vehicle to reduce it to the second target speed, thereby increasing the distance between the following vehicle and the leading vehicle by the first adjustment distance d adjust The process of reducing the speed of the following vehicle is as follows:

[0067] 221) Based on the second target vehicle speed of the following vehicle, the second target acceleration a of the following vehicle is calculated by PID control through expressions (24) and (25): target_i :

[0068] V target -V ego =V delta (twenty four)

[0069]

[0070] Among them, V target is the second target speed of the following vehicle, V ego is the actual speed of the following vehicle, V delta is the difference between the second speed of the following vehicle and the actual speed, k p1 , k p1 and k d1 are all constants.

[0071] 222) Based on the following vehicle driving information, the leading vehicle driving information and the actual following distance between the following vehicle and the leading vehicle, a third target acceleration a of the following vehicle is calculated by a step similar to that in step S12 above. target_follow_i ; During the deceleration of the following vehicle, the second target acceleration a target_i and the third target acceleration a target_follow_i All are negative values.

[0072] 223) Set the second target acceleration a of the following vehicle target_i The third target acceleration a of the following vehicle target_follow_i Specifically, the difference between the second target acceleration of the following vehicle and the third target acceleration of the following vehicle is calculated, and when the difference between the third target acceleration and the second target acceleration is greater than a preset value (the preset value is a negative value), the smaller of the second target acceleration and the third target acceleration is used to control the brake pedal opening of the following vehicle to reduce the speed of the following vehicle.

[0073] And in the third target acceleration a target_follow_i and the second target acceleration a target_i When the difference between the following and preceding vehicles is less than a preset value, it means that the following distance between the following vehicle and the preceding vehicle is difficult to ensure. In this case, the following vehicle is made to enter the platoon disbanding mode to leave the truck platoon.

[0074] S23: After the speed of the following vehicle decreases to the second target speed, it means that the distance between the following vehicle and the leading vehicle has increased by the first adjustment distance d adjust After that, the speed of the following vehicle needs to be gradually increased until it reaches the same speed as the leading vehicle. At this time, the speed of the leading vehicle can be the stable driving speed V when the trucks are driving in formation. i_fix , the driving stable speed may be equal to the first target speed. In the process of gradually increasing the speed of the following vehicle, the distance between the following vehicle and the leading vehicle may be further increased by the first adjustment distance d adjust half of the distance between the following vehicle and the leading vehicle until the distance between the following vehicle and the leading vehicle is substantially equal to the second target following distance. After that, the following vehicle will continue to follow the leading vehicle at the second target following distance. The second target following distance may be equal to the first target following distance and the first adjustment distance d adjust The sum of .

[0075] After all trucks except the lead truck in the truck formation have taken the above control steps, even if the wireless communication connection of the trucks may be disturbed, the distance between any two adjacent vehicles in the front and rear of the truck formation can be adjusted to the second target following distance, thereby maintaining the safe driving of the truck queue.

[0076] In addition, in the formation adjustment mode, it is also necessary to monitor the wireless communication connection in real time. If the wireless communication connection is abnormal for a predetermined period of time, it means that it becomes more difficult to continue to maintain the truck queue. At this time, it is necessary to make the following vehicle enter the formation dissolution mode, leave the truck formation and drive on its own.

[0077] However, while the following vehicle is traveling in the formation adjustment mode, if it is detected that the wireless communication connection of the following vehicle has returned to normal, the following vehicle is caused to travel in the formation recovery mode. In the formation recovery mode, the speed of the following vehicle is adjusted to reduce the distance between the following vehicle and the leading vehicle, so that the following vehicle follows the leading vehicle at a third target following distance, which is smaller than the second target following distance, and the third target following distance may be equal to the first target following distance.

[0078] In the formation recovery mode, since the wireless communication connection of the following vehicle has been restored to normal, the speed of the following vehicle can be controlled based on the accelerator pedal opening and brake pedal opening (or acceleration) of the leading vehicle, so that any two adjacent trucks in the front and rear of the truck formation can be driven at a smaller following distance than in the formation adjustment mode. At this time, it is first necessary to increase the speed of the following vehicle to reduce the distance between the following vehicle and the leading vehicle. After the speed of the following vehicle is reduced to the third target speed, it is necessary to reduce the speed of the following vehicle to further reduce the distance between the following vehicle and the leading vehicle, until the rear vehicle and the leading vehicle are separated by the second target following distance. The control of the vehicle speed in the formation recovery mode is described in detail below.

[0079] S31: Based on the current speed of the leading vehicle of the truck formation, determine the second adjustment distance between the following vehicle and the leading vehicle to be reduced, and then calculate the third target speed of the following vehicle in the formation adjustment mode based on the second adjustment distance. The third target speed may be greater than the second target speed. The specific calculation of the third target speed is as follows:

[0080] 311) Obtain the stable driving speed V of the following vehicle when maintaining the truck platoon ifix ′;

[0081] 312) Preset the second adjustment distance d to be reduced between the following vehicle and the preceding vehicle adjust ′, the maximum speed V in the truck platoon max Among them, the second adjustment distance d adjust ′ is related to the current speed of the leading vehicle in the truck formation. If the current speed of the leading vehicle in the truck formation is 120 km / h, the second adjustment interval d adjust ′ is set to 20m, for example. If the current speed of the leading vehicle in the truck formation is 100km / h, the second adjustment distance d adjust ' is set to 10m, for example, and if the current speed of the leading vehicle in the truck formation is 60km / h, the second adjustment distance d adjust ' is set to 5m, for example, that is, the second adjustment distance d adjust The value of ′ increases with the increase of the current speed of the leading vehicle in the truck formation, and decreases with the decrease of the current speed of the leading vehicle in the truck formation. max is the maximum preset speed of the last truck in the truck platoon, which is related to the length of the truck platoon (i.e., the number of trucks in the truck platoon) and the maximum speed limit of the highway. For example, if the maximum speed limit of the highway is 120 km / h and the truck platoon is traveling at a speed of 90 km / h, if the truck platoon only includes two trucks, i.e., a leading truck and a following truck, then the maximum speed V in the truck platoon is max is the maximum speed of the following vehicle, which can be preset to 100 km / h; if the truck formation includes four trucks, namely one leading truck and three following trucks, then the maximum speed V in the truck formation is max is the maximum speed of the last following vehicle in the truck formation, which can be preset to 120 km / h. Then, the adjustment time t required for the entire truck formation to complete speed adjustment can be calculated according to the following expression (31): adjust ′;

[0082]

[0083] Where n is the number of trucks in the truck platoon.

[0084] 313) Calculate the speed difference V that the following vehicle needs to increase according to the following expression (32): inc_i :

[0085]

[0086] 314) Calculate the third target vehicle speed V of the following vehicle in the platoon recovery mode according to the following expression (33): target_i ′:

[0087]

[0088] Among them, t counter =t adjust ′×j sum , j sum is a function of j, where j is the calculation period, i.e., the number of calculations. When the calculation period increases once, j increases by 1 accordingly; and when the adjustment calculation begins, j increases from 1. When j <= 0.5*t adjust ′, j sum =j; when j>0.5*t adjust ′, j changes from 0.5*t adjust ′ starts to decrease, j sum =j-1; when j=t adjust ′, j sum =0, at this time j can stop increasing, and the third target vehicle speed V is calculated at this time target_i ′.

[0089] S32: After calculating the third target speed of the following vehicle in the platoon recovery mode, increase the speed of the following vehicle to the third target speed, thereby reducing the distance between the following vehicle and the leading vehicle by the second adjustment distance d adjust The process of increasing the speed of the following vehicle is as follows:

[0090] 321) Based on the third target vehicle speed of the following vehicle, the fourth target acceleration a of the following vehicle is calculated by using PID control target_i ′, the fourth target acceleration of the following vehicle is calculated using the above formulas (24) and (25);

[0091] 322) Based on the following vehicle driving information, the leading vehicle driving information and the actual following distance between the following vehicle and the leading vehicle, a fifth target acceleration a of the following vehicle is calculated using steps similar to steps S11 to S13 above. target_follow_i '; In the formation recovery mode, the fourth target acceleration and the fifth target acceleration are both positive values.

[0092] 323) Compare the fourth target acceleration of the following vehicle with the fifth target acceleration of the following vehicle, and use the smaller of the fourth target acceleration and the fifth target acceleration to increase the speed of the following vehicle.

[0093] S33: After the speed of the following vehicle increases to the third target speed, it means that the distance between the following vehicle and the leading vehicle has been reduced by the second adjustment distance d adjust ′, and then gradually reduce the speed of the following vehicle to the stable speed V of the following vehicle when maintaining the truck platoon. ifix ′, stable driving speed V ifix ' can be equal to the first target speed, or can be equal to the current speed of the preceding vehicle or the current speed of the leading vehicle of the truck formation. During the period of reducing the speed of the following vehicle, the distance between the following vehicle and the preceding vehicle can be further reduced by the second adjustment distance d adjust ', until the distance between the following vehicle and the leading vehicle is substantially equal to the third target following distance. After that, the following vehicle will continue to follow the leading vehicle at the third target following distance. The third target following distance can be equal to the second target distance and the second adjustment distance d adjust The difference of ′.

[0094] Afterwards, the entire truck platoon can return to operating in platooning mode.

[0095] Therefore, based on the above control method, the speed of each truck in the entire truck queue can be controlled, so that regardless of whether the wireless communication connection of the truck is normal, the following distance of each truck can be coordinated to improve the safety of truck platoon driving, while continuing to maintain queue driving.

[0096] In addition, through the description of the above embodiments, it will be understood by those skilled in the art that all or some steps and systems in the above disclosed methods can be implemented as software, firmware, hardware and appropriate combinations thereof. Some physical components or all physical components can be implemented as software executed by a processor, such as a central processing unit, a digital signal processor or a microprocessor, or implemented as hardware, or implemented as an integrated circuit, such as an application-specific integrated circuit. Such software can be distributed on a computer-readable medium, and the computer-readable medium can include a computer storage medium (or a non-transitory medium) and a communication medium (or a temporary medium). As known to those skilled in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as a computer-readable signal, a data structure, a program module or other data). Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disk (DVD) or other optical disk storage, magnetic cassette, magnetic tape, disk storage or other magnetic storage device, or any other medium that can be used to store desired information and can be accessed by a computer. Furthermore, it is well known to those skilled in the art that communication media generally embodies computer readable signals, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

[0097] Although the present invention has been described with reference to preferred embodiments, various modifications may be made thereto and elements thereof may be replaced by equivalents without departing from the scope of the present invention. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there is no structural conflict. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A vehicle following control method based on a truck formation, wherein the truck formation comprises a lead vehicle and at least one follower vehicle following the lead vehicle, wherein: The following vehicle control method comprises the following steps: for each following vehicle, When it is detected that the wireless communication connection is normal, the following vehicle is driven in a platoon driving mode, and in the platoon driving mode, the speed of the following vehicle is adjusted so that the following vehicle follows the leading vehicle at a first target speed substantially the same as that of the leading vehicle traveling in front of the following vehicle, so that a first target following distance is substantially maintained between the following vehicle and the leading vehicle; and When an abnormality in the wireless communication connection is detected, the following vehicle is caused to travel in a formation adjustment mode. In the formation adjustment mode, the speed of the following vehicle is adjusted to increase the distance between the following vehicle and the leading vehicle, so that the following vehicle follows the leading vehicle at a second target following distance, and the second target following distance is greater than the first target following distance.

2. The vehicle following control method according to claim 1, wherein: The step of adjusting the speed of the following vehicle in the platoon driving mode includes: Obtaining the accelerator pedal opening and brake pedal opening of the preceding vehicle; Calculating a first target acceleration of the following vehicle by using a linear quadratic regulation control based on the following vehicle driving information, the leading vehicle driving information and the actual following distance between the following vehicle and the leading vehicle; Calculating a target accelerator pedal opening of the following vehicle based on the accelerator pedal opening of the leading vehicle and the first target acceleration of the following vehicle, or calculating a target brake pedal opening of the following vehicle based on the brake pedal opening of the leading vehicle and the first target acceleration of the following vehicle, wherein the first target acceleration of the following vehicle is less than 0 when calculating the target brake pedal opening of the following vehicle; Based on the target accelerator pedal opening or the target brake pedal opening of the following vehicle, the vehicle speed of the following vehicle is adjusted so that the following vehicle has a first target vehicle speed substantially the same as that of the leading vehicle.

3. The vehicle following control method according to claim 1, wherein: The step of adjusting the speed of the following vehicle in the formation adjustment mode includes: reducing the speed of the following vehicle so that the distance between the following vehicle and the leading vehicle increases by half of the first adjustment distance; and After the distance between the following vehicle and the leading vehicle increases by half of the first adjustment distance, the speed of the following vehicle is gradually increased to be consistent with the speed of the leading vehicle, so that the distance between the following vehicle and the leading vehicle is increased by half of the first adjustment distance again, until the distance between the following vehicle and the leading vehicle is the second target following distance, and the following vehicle will then continue to follow the leading vehicle at the second target following distance.

4. The vehicle following control method according to claim 3, wherein: The step of adjusting the speed of the following vehicle in the formation adjustment mode includes: Determining the first adjustment distance to be increased between the following vehicle and the leading vehicle based on the current vehicle speed of the leading vehicle of the truck formation; Calculating a second target vehicle speed of the following vehicle in the platoon adjustment mode based on the first adjustment interval; The speed of the following vehicle is adjusted to decrease to the second target speed, so that the distance between the following vehicle and the leading vehicle increases by half of the first adjustment distance.

5. The vehicle following control method according to claim 4, wherein: The step of adjusting the speed of the following vehicle in the formation adjustment mode further includes: After the speed of the following vehicle decreases to the second target speed, the speed of the following vehicle is gradually increased to the stable driving speed of the following vehicle when maintaining the truck platoon driving, so that the distance between the following vehicle and the leading vehicle is increased again by half of the first adjustment distance, until the following vehicle and the leading vehicle are separated by the second target following distance, wherein the stable driving speed is equal to the first target speed.

6. The vehicle following control method according to claim 4 or 5, wherein: The step of adjusting the speed of the following vehicle in the formation adjustment mode further includes: Calculating a second target acceleration of the following vehicle by using PID control based on the second target vehicle speed of the following vehicle; Based on the following vehicle driving information, the leading vehicle driving information and the actual following distance between the following vehicle and the leading vehicle, a third target acceleration of the following vehicle is obtained by linear quadratic adjustment; The second target acceleration of the following vehicle is compared with a third target acceleration of the following vehicle, and the vehicle speed of the following vehicle is reduced by using the smaller one of the second target acceleration and the third target acceleration.

7. The vehicle following control method according to claim 6, wherein: The step of adjusting the speed of the following vehicle in the formation adjustment mode further includes: When the difference between the third target acceleration and the second target acceleration is less than a preset value, the following vehicle is caused to enter a platoon disbanding mode to leave the truck platoon.

8. The vehicle following control method according to claim 4 or 5, wherein: In the formation adjustment mode, after the speed of the following vehicle decreases to the second target speed, if a wireless communication connection abnormality is detected for a predetermined period of time, the following vehicle is caused to enter a formation disbanding mode to leave the truck formation.

9. The vehicle following control method according to claim 1, wherein: The following vehicle control method further comprises the following steps: During the period when the following vehicle is traveling in the formation adjustment mode, if it is detected that the wireless communication connection has returned to normal, the following vehicle is caused to travel in the formation recovery mode. In the formation recovery mode, the speed of the following vehicle is adjusted to reduce the distance between the following vehicle and the leading vehicle, so that the following vehicle follows the leading vehicle at a third target following distance, and the third target following distance is smaller than the second target following distance.

10. The vehicle following control method according to claim 9, wherein: The step of adjusting the speed of the following vehicle in the formation recovery mode comprises: Increasing the speed of the following vehicle so that the distance between the following vehicle and the leading vehicle is reduced by half of the second adjustment distance; and After the distance between the following vehicle and the leading vehicle is reduced by half of the second adjustment distance, the speed of the following vehicle is gradually reduced to the stable driving speed of the formation driving mode, so that the distance between the following vehicle and the leading vehicle is reduced by half of the second adjustment distance again, until the distance between the following vehicle and the leading vehicle is the third target following distance, and the following vehicle will then continue to follow the leading vehicle at the third target following distance.

11. The vehicle following control method according to claim 9, wherein: The step of adjusting the speed of the following vehicle in the formation recovery mode comprises: Determining the second adjustment distance to be reduced between the following vehicle and the leading vehicle based on the current vehicle speed of the leading vehicle of the truck formation; Calculating a third target vehicle speed of the following vehicle in the formation adjustment mode based on the second adjustment interval; The speed of the following vehicle is adjusted to increase to the third target speed, so that the distance between the following vehicle and the leading vehicle is reduced by half of the second adjustment distance.

12. The vehicle following control method according to claim 11, wherein: The step of adjusting the speed of the following vehicle in the formation recovery mode comprises: After the speed of the following vehicle increases to the third target speed, the speed of the following vehicle is gradually reduced to the stable driving speed of the following vehicle when maintaining the truck platoon driving, so that the distance between the following vehicle and the leading vehicle is reduced again by half of the second adjustment distance, until the distance between the following vehicle and the leading vehicle is the third target following distance, wherein the stable driving speed is equal to the first target speed.

13. The vehicle following control method according to claim 11 or 12, wherein: The step of adjusting the speed of the following vehicle in the formation recovery mode further includes: Based on the third target vehicle speed of the following vehicle, calculating a fourth target acceleration of the following vehicle by using PID control; Calculating a fifth target acceleration of the following vehicle by using a linear quadratic adjustment based on the following vehicle driving information, the leading vehicle driving information and the actual following distance between the following vehicle and the leading vehicle; The fourth target acceleration of the following vehicle is compared with a fifth target acceleration of the following vehicle, and the vehicle speed of the following vehicle is increased by using the smaller one of the fourth target acceleration and the fifth target acceleration.

14. The vehicle following control method according to claim 11 or 12, wherein: The step of adjusting the speed of the following vehicle in the formation recovery mode further includes: When the actual vehicle speed of the following vehicle returns to the stable driving speed, the following vehicle is caused to travel in the platoon driving mode.

15. A vehicle following control system based on a truck platoon, which is capable of executing the vehicle following control method according to any one of claims 1 to 14.

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