A method for vehicle cooperative adaptive cruise control

Abstract

An embodiment of the present invention provides a method for vehicle cooperative adaptive cruise control, wherein the vehicles form a fleet through a wireless network, and the method comprises: obtaining dynamic information of a first vehicle in the fleet and dynamic information of a vehicle preceding the vehicle; determining following reference information of the vehicle under a plurality of preset following strategies according to the dynamic information of the first vehicle in the fleet, the dynamic information of the vehicle preceding the vehicle, and a dynamic transfer function between each vehicle and the first vehicle, wherein the following reference information comprises driving control parameters and relationship curves of the vehicle under a plurality of communication delays in each following strategy, wherein the relationship curve comprises the minimum driving distance required to satisfy driving stability under a plurality of communication delays; selecting the optimal following strategy according to the communication delay of the vehicle and the following reference information, and calculating the control output for driving control according to the corresponding driving control parameters.

Description

Technical Field

[0001] The present invention relates to the field of intelligent transportation, and more specifically, to cooperative convoy driving in an intelligent transportation system. The present invention can be applied to the longitudinal motion control of an outdoor convoy driving system, and more specifically, to a method for cooperative adaptive cruise control of vehicles. Background Art

[0002] The establishment and improvement of transportation facilities play an important role in promoting social development. However, due to the significant increase in traffic volume and some drivers not following regulations, traffic congestion and low traffic efficiency will occur.

[0003] Some researchers first proposed Adaptive Cruise Control (ACC), which can sense the driving environment with the help of on-board sensors (such as radar, lidar or camera sensor system) and adjust the speed based on the distance between vehicles to match the speed of the vehicle in front, ensuring that the vehicle and the vehicle in front can maintain a certain driving distance. However, there is no direct information exchange between vehicles, so a large safety distance needs to be reserved, and the road is not fully utilized.

[0004] As an extension of ACC, some researchers later proposed the Cooperative Adaptive Cruise Control System (CACC), in which, based on ACC, vehicles can form a convoy through vehicle-to-vehicle wireless communication technology (such as V2X technology), and vehicles can control their own driving based on the kinematic information of the vehicle in front. When using the data of the vehicle in front, the CACC system can have a shorter and more accurate time difference control compared to the ACC system, which helps to improve traffic throughput and reduce fuel consumption.

[0005] The CACC system is widely considered to be an effective solution to traffic problems because it has the ability to improve road efficiency and traffic flow. The CACC system can realize automatic longitudinal control of the convoy. The main goal of the CACC system is to maintain the uniformity of all behaviors of the vehicles in the convoy and ensure the vehicle spacing that meets stability. The vehicles in the convoy will establish a communication network for periodic sharing of kinematic information. Therefore, the vehicle can receive kinematic information such as speed, acceleration and position of the preceding vehicle or its adjacent vehicles determined according to the predefined network topology. The control strategy based on real-time information sharing between vehicles is more reasonable and can also reduce the driving distance.

[0006] Some researchers proposed a CACC controller consisting of feedforward and feedback parameters, taking into account the effect of communication delay on the longitudinal control of the vehicle given a fixed driving distance. The effect of communication delay on the stability of the string was studied. The results show that if the communication delay exceeds 50 milliseconds, the stability of the string will be destroyed. Some researchers proposed an optimization-based CACC control method for a single-vehicle predecessor network topology and a fixed driving distance, taking into account factors such as communication delay and packet loss rate. The results show that the designed controller can maintain the stability of the string below 0.293 seconds. Some researchers focused on the proportional-differential controller and derived the relationship between the communication delay and the driving distance that meets the stability requirements. The results show that when the communication delay increases from 0.02s to 0.1s, the minimum driving distance needs to be nonlinearly increased to double to maintain the stability of the string.

[0007] In a CACC system fleet, vehicles share information based on a fixed following strategy based on a wireless self-organizing network (vehicle wireless network, such as V2X). The CACC system of a vehicle usually consists of external input, control strategy, driving gap, vehicle kinematic module and feedback module. The external input module is composed of kinematic information sharing of other vehicles. The goal of the control strategy is to generate a desired kinematic information based on the input kinematic information and the strategy of driving gap. The stability of the string is an indicator for evaluating the CACC system. If the CACC system can meet the requirements of stability, the CACC system will not propagate to the rear when there are disturbances such as speed in the front vehicle in the fleet, thereby reducing traffic congestion. In existing studies, CACC adopts a fixed following strategy. According to the range of conventional communication delay, the control input and feedback information are designed to design CACC to achieve the minimum driving gap that meets stability. If the design takes into account the situation when the communication status is good, the CACC designed in this way can achieve the optimal driving gap under stability and improve the throughput of the traffic system. However, once the communication conditions are poor, the system is very likely to cause instability, generate speed disturbance waves, spread to the surroundings, and cause traffic jams. However, the communication delay considered in the design of CACC is too large, and the driving interval achieved by such a system to meet stability will not be optimal, reducing the throughput of the transportation system.

[0008] In general, the existing technology adopts a fixed vehicle-following strategy and analyzes the minimum driving distance that satisfies driving stability within the range of conventional communication delay (mainly considering the maximum delay), so that each vehicle in the fleet cruises with the goal of maintaining the minimum driving distance. However, the communication delay is variable, and the existing technology fails to effectively improve the road use efficiency according to the specific situation of the communication delay. Therefore, it is necessary to improve the existing technology. Summary of the invention

[0009] Therefore, the purpose of the present invention is to overcome the above-mentioned defects of the prior art and provide a method for vehicle cooperative adaptive cruise control. The method is used in the longitudinal motion control aspect of driving control.

[0010] The objective of the present invention is achieved through the following technical solutions:

[0011] According to a first aspect of the present invention, a method for vehicle cooperative adaptive cruise control is provided, wherein the vehicles form a fleet through a wireless network, and the method comprises: obtaining dynamic information of a first vehicle in the fleet and dynamic information of a vehicle preceding the present vehicle; determining following reference information of the present vehicle under a plurality of preset following strategies according to the dynamic information of the first vehicle in the fleet, the dynamic information of the vehicle preceding the present vehicle, and a dynamic transfer function between each vehicle and the first vehicle, the following reference information comprising driving control parameters and relationship curves of the present vehicle under a plurality of communication delays in each following strategy, the relationship curve comprising the minimum driving distances required to satisfy driving stability under a plurality of communication delays; selecting the optimal following strategy according to the communication delay of the present vehicle and the following reference information, and calculating the control output for driving control according to the corresponding driving control parameters.

[0012] In some embodiments of the present invention, the multiple following strategies are N following strategies, wherein the following strategy of following n vehicles represents a strategy for a vehicle to follow the n vehicles in front, under which driving control needs to refer to the dynamic information of the n vehicles in front, wherein 1≤n≤N, and n and N are both integers.

[0013] In some embodiments of the present invention, the relationship curve corresponding to each following strategy is obtained in the following manner: according to a preset communication delay solution range and a predetermined step size, the predetermined step size is gradually increased starting from an initial communication delay to analyze the driving control parameters under the corresponding communication delay in the communication delay solution range; according to the corresponding communication delay and the corresponding driving control parameters, the minimum driving distance required for the corresponding communication delay to meet driving stability is calculated.

[0014] In some embodiments of the present invention, the driving control parameters corresponding to the corresponding communication delay of each following strategy are the driving control parameters obtained by minimizing the infinite norm of the dynamic transfer function in the algebraic Riccati equation based on the delay in the current vehicle executing control, the corresponding communication delay and the dynamic transfer function under the following strategy.

[0015] In some embodiments of the present invention, the corresponding dynamic transfer function when the corresponding vehicle adopts the following strategy of following n vehicles is expressed as:

[0016]

[0017] Among them, ui (s) represents the dynamic information of vehicle i, u1(s) represents the dynamic information of the first vehicle in the convoy, K fb (s) represents the feedback control parameter, G i (s) represents the transfer function of vehicle kinematics, q i (s) represents the position information, τ i represents the internal delay of vehicle i, represents the time delay of vehicle i to execute control, H -1 represents the inverse transformation function of the vehicle spacing function H. The vehicle spacing function H is expressed in the Laplace domain as H(s)=hs+1, where h represents the reserved safety spacing, and K ff，i-1 Represents Θ i-1 The corresponding feedforward control parameter, K ff，i-2 Represents Θ i-2 The corresponding feedforward control parameter, K ff，i-n Represents Θ i-n The corresponding feedforward control parameter, D(s), represents the communication delay transfer function, D(s) = e -θs , e represents the base of natural logarithm, θ represents the communication delay, and the letter followed by (s) indicates that the corresponding function is analyzed in the Laplace domain, and s represents the Laplace operator.

[0018] In some embodiments of the present invention, the optimal following strategy is selected as follows: according to the communication delay of the vehicle, the following strategy corresponding to the minimum driving distance at the communication delay is determined based on the reference relationship of multiple following strategies, and it is used as the optimal following strategy.

[0019] In some embodiments of the present invention, the driving control of the vehicle according to the optimal following strategy includes: when the originally adopted following strategy is different from the optimal following strategy, switching the dynamic information referenced by the driving control and the driving distance between the vehicle and the vehicle in front according to the optimal following strategy.

[0020] In some embodiments of the present invention, the communication delay of the vehicle is an estimated communication delay, and the information referenced for estimating the communication delay includes transmission power information of the communication unit of the relevant vehicle, signal-to-noise ratio, vehicle-to-vehicle distance change information, or a combination thereof.

[0021] According to a second aspect of the present invention, a vehicle supporting cooperative adaptive cruise control is provided, comprising: a communication unit, for obtaining dynamic information of the first vehicle in the convoy and the dynamic information of the vehicle preceding the vehicle, and transmitting the dynamic information of the vehicle to the vehicle behind the vehicle in the convoy; a following strategy analysis module, for determining following reference information of the vehicle under a plurality of preset following strategies according to the dynamic information of the first vehicle in the convoy, the dynamic information of the vehicle preceding the vehicle, and the transfer function of the dynamics of each vehicle and the first vehicle, the following reference information comprising driving control parameters and relationship curves of the vehicle under a plurality of communication delays in each following strategy, the relationship curve comprising minimum driving distances required to satisfy driving stability under a plurality of communication delays; a controller, for selecting an optimal following strategy according to the communication delay of the vehicle and the following reference information, and calculating a control output for driving control according to the driving control parameters corresponding to the communication delay of the vehicle in the selected optimal following strategy, and calculating a following error according to the position information of the preceding vehicle and the position information of the vehicle and adjusting the control output for driving control.

[0022] According to a third aspect of the present invention, an electronic device comprises: one or more processors; and a memory, wherein the memory is used to store executable instructions; the one or more processors are configured to implement the steps of the method described in the first aspect by executing the executable instructions. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The embodiments of the present invention are further described below with reference to the accompanying drawings, in which:

[0024] Figure 1 A schematic flow chart of a method for vehicle cooperative adaptive cruise control according to an embodiment of the present invention;

[0025] Figure 2 A schematic diagram of a vehicle fleet in a method for cooperative adaptive cruise control of vehicles according to an embodiment of the present invention;

[0026] Figure 3 is a curve showing the relationship between the communication delay and the minimum driving distance in the method for vehicle cooperative adaptive cruise control according to an embodiment of the present invention;

[0027] Figure 4 It is a schematic diagram of the simulation results of the following errors of different following strategies according to an embodiment of the present invention;

[0028] Figure 5 It is a schematic diagram of the principle of driving control when a following strategy of following n vehicles is adopted in the vehicle cooperative adaptive cruise control method according to an embodiment of the present invention;

[0029] Figure 6It is a schematic diagram of the principle of controlling the vehicle after adjusting the following strategy in a vehicle supporting cooperative adaptive cruise control according to an embodiment of the present invention. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below through specific embodiments in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0031] As mentioned in the background technology section, the prior art adopts a fixed following strategy and analyzes the minimum driving distance that satisfies driving stability within the range of conventional communication delay (mainly considering the maximum delay), allowing each vehicle in the fleet to cruise with the goal of maintaining the minimum driving distance, but the communication delay is variable, and the prior art has not been able to effectively improve road use efficiency based on the specific circumstances of the communication delay. The present invention changes the following mode of cooperative adaptive cruise control from a fixed following strategy to support multiple following strategies, considers the relationship curve between communication delay and driving distance under a variety of different following strategies, and adaptively selects the optimal following strategy from a variety of following strategies based on the communication delay of the vehicle. The optimal following strategy corresponds to the following strategy that achieves the minimum driving distance under the communication delay of the vehicle; from the perspective of the CACC system composed of all vehicles in the fleet, the optimal driving distance is achieved as a whole, improving road utilization.

[0032] The present invention provides a method for cooperative adaptive cruise control, which supports vehicles to share information within the fleet after forming a fleet through a wireless network (a wireless communication network for vehicles, such as a wireless network based on V2X technology) to collaboratively perform adaptive cruise control, and supports N switchable following strategies, wherein the following strategy of following n vehicles means a strategy for the vehicle to follow the n vehicles in front, and under this strategy, it is necessary to refer to the dynamic information of the n vehicles in front for driving control (1≤n≤N, N>1). When the vehicle is driving on the road, it searches for other vehicles on the road that support the method of the present invention and forms a fleet with them. When and after forming a fleet, the vehicle will analyze the minimum driving distance required for driving stability under various communication delays in different following strategies, and select the following strategy based on the communication delay of the vehicle, so as to adopt the following strategy corresponding to the minimum driving distance that can meet the driving stability under the communication delay of the vehicle, so as to dynamically adjust the driving distance according to the communication delay, and reduce the influence of bad communication conditions on the driving performance of the fleet; thus, the present invention can make full use of road space and improve road utilization according to the specific situation of communication delay.

[0033] The following references Figure 1 and Figure 2, a method of cooperative adaptive cruise control according to an embodiment of the present invention is described, including steps S1, S2, and S3. Among them:

[0034] Step S1: Obtain the dynamic information of the first vehicle in the convoy and the dynamic information of the vehicle preceding the vehicle.

[0035] According to one embodiment of the present invention, the first vehicle in the convoy refers to the first vehicle in the convoy. Figure 2 The vehicle numbered 1 is shown in FIG. The dynamic information includes, for example, the position, speed, acceleration, or a combination thereof of the vehicle.

[0036] Step S2: According to the dynamic information of the first vehicle in the convoy, the dynamic information of the vehicle before the vehicle, and the dynamic transfer function between each vehicle and the first vehicle, determine the following reference information of the vehicle under the preset multiple following strategies, the following reference information includes the driving control parameters and relationship curves of the vehicle under multiple communication delays in each following strategy, and the relationship curve includes the minimum driving distance required to meet driving stability under multiple communication delays.

[0037] According to a preferred embodiment of the present invention, see Figure 2 , assuming that the current vehicle i (this vehicle) is at the end of the convoy, and the upper limit of the number of following vehicles in the following strategy is configured to follow n vehicles, it is necessary to sequentially find the driving control parameters and relationship curves of the following strategies of following 1 vehicle, following 2 vehicles, ..., following n vehicles at different communication delays.

[0038] To this end, the present invention defines the transfer function of the dynamics corresponding to the following strategy of a vehicle following n vehicles as shown in the following formula 1:

[0039]

[0040] Among them, u i (s) represents the dynamic information of vehicle i, u1(s) represents the dynamic information of the first vehicle in the convoy, K fb (s) represents the feedback control parameter, G i (s) represents the transfer function of vehicle kinematics, q i (s) represents the position information, τ i represents the internal delay of vehicle i, represents the time delay of vehicle i to execute control, H -1 represents the inverse transformation of the driving distance H, which is expressed in the Laplace domain as H(s)=hs+1, where h represents the reserved safety distance, and K ff，i-1 Represents Θ i-1 The corresponding feedforward control parameter, K ff，i-2 Represents Θi-2 The corresponding feedforward control parameter, K ff，i-n Represents Θ i-n The corresponding feedforward control parameter, D(s), represents the communication delay transfer function, D(s) = e -θs , e represents the base of the natural logarithm, θ represents the communication delay, the letter followed by (s) indicates that the corresponding function is analyzed in the Laplace domain, and s represents the Laplace operator. In one embodiment of the present invention, when calculating the dynamic transfer function, the dynamic information used is acceleration, that is, the dynamic transfer function represents the acceleration ratio. However, it should be understood that in some more complex application scenarios, the implementer can use more information in the dynamic information, not limited to the acceleration information.

[0041] When solving, it is necessary to calculate according to the preset communication delay solution range. The range can be pre-configured by default or adjusted by the user as needed. Assuming that the communication delay solution range is configured as (0-0.5], in seconds, and the step size is set to 0.01s, the solution is performed as follows:

[0042] Starting from the communication delay of 0.01s, the driving control parameters corresponding to the following strategies of following 1 car, following 2 cars, ..., following n cars are calculated in turn, where:

[0043] For the following strategy of following one vehicle, Formula 1 can be expressed as Given the communication delay θ, the internal delay τ of the vehicle, and the delay of the vehicle executing control (actuator delay) and the reserved safety distance h are used to solve G(s), D(s), and H(s). When the three variables G(s), D(s), and H(s) are known, the control parameters when the infinite norm of the transfer function of the corresponding system is minimized can be solved by solving the algebraic Riccati Equations, which satisfies Driving control parameter K i (s)=(K fb (s)K ff,i-1 (s)); Analyze whether the dynamic transfer function corresponding to the driving control parameters obtained meets the stability requirements, that is, ||Θ i (s)|| H∞ ≤1, if the stability requirement is met, search for the minimum driving distance, and satisfy

[0044] For the following strategy of following two vehicles, Formula 1 can be expressed as The driving control parameter K according to the following strategy of following 1 vehicle i(s)=(K fb (s)K ff,i-1 (s)) and G(s), D(s), H(s), and obtain the transfer function Θ of the following strategy for following one vehicle i-1 (s). i-1 (s), G(s), D(s), H(s), the unknown variables in formula 1 are K(s), Θ i (s). By solving the algebraic Riccati equation, the driving control parameters when the infinite norm of the corresponding transfer function is minimized are obtained to satisfy Driving control parameters, K i (s)=(K fb (s)K ff,i-1 (s),K ff,i-2 (s)); Analyze whether the dynamic transfer function corresponding to the driving control parameters obtained meets the stability requirements, that is, ||Θ i (s)|| H∞ ≤1, if the stability requirement is met, search for the minimum driving distance, and satisfy

[0045] Similarly, the driving control parameters corresponding to the following strategy of following more vehicles can be calculated in sequence until the control parameter K corresponding to the following strategy of following n vehicles is completed. i (s)=(K fb (s)K ff,i-1 (s),K ff,i-2 (s)…K ff,i-n (s)) calculation; analyze whether the dynamic transfer function corresponding to the driving control parameters obtained meets the stability requirements, that is, ||Θ i (s)|| H∞ ≤1, if the stability requirement is met, search for the minimum driving distance, and satisfy

[0046] Then increase the analyzed communication delay by 0.01s, and repeat all the above steps until the solution of multiple communication delays within the 0.5s set in the communication delay solution range is completed. For example, if only the relationship curve corresponding to the following strategy of following 1-3 vehicles is analyzed, the following is obtained: Figure 3 The corresponding relationship curves are shown.

[0047] Step S3: According to the communication delay of the vehicle and the reference information of the vehicle following, the optimal vehicle following strategy is selected, and the control output for vehicle driving control is calculated according to the corresponding vehicle driving control parameters, thereby dynamically adjusting the driving distance.

[0048] According to one embodiment of the present invention, the communication delay of the vehicle is an estimated communication delay, and the information referred to in estimating the communication delay includes transmission power information of the communication unit of the relevant vehicle, signal-to-noise ratio, vehicle spacing change information between vehicles, or a combination thereof. For example, after forming a convoy, the vehicles in the convoy will share the information referred to in calculating the communication delay with each other, so that the corresponding vehicles can estimate the communication delay.

[0049] According to an embodiment of the present invention, step S3 includes: according to the communication delay of the vehicle, based on the reference relationship of multiple following strategies, determine the following strategy corresponding to the minimum driving distance at the communication delay of the vehicle, and use it as the optimal following strategy; when the original following strategy is different from the optimal following strategy, switch the dynamic information referenced by the driving control and the driving distance between the vehicle and the preceding vehicle according to the optimal following strategy. Preferably, the driving distance can refer to the interval reserved in time or the distance reserved in position space between the two vehicles.

[0050] According to an example of the present invention, if Figure 3 The corresponding relationship curves shown in FIG. 1 show that the minimum driving distance corresponds to the following strategy of following one vehicle when the communication delay is between 0 and 0.24 seconds. The minimum driving distance corresponds to the following strategy of following two vehicles when the communication delay is between 0.24 and 0.31 seconds, and the minimum driving distance corresponds to the following strategy of following three vehicles when the communication delay is greater than 0.31 seconds. Since the minimum driving distance required to maintain driving stability under the corresponding communication delay of different following strategies is different, when switching the following strategy, the minimum driving distance required to maintain driving stability under the corresponding communication delay of the following strategy will be used as the expected driving distance.

[0051] According to an embodiment of the present invention, during driving, the influence of time delay on dynamic information is also considered. Step S3 also includes: using the communication delay transfer function to correct the dynamic information referenced by driving control, and using the corresponding driving control parameters, the following vehicle error and the corrected corresponding dynamic information to calculate the control output for driving control. In this way, the influence of communication delay on driving control is reduced, and driving safety is guaranteed.

[0052] According to an embodiment of the present invention, the error problem is also considered during driving. Preferably, step S3 also includes: in the process of the vehicle executing the corresponding driving control parameters, the following error is calculated according to the position information of the preceding vehicle and the position information of the vehicle, and the control output for driving control is adjusted to reduce the following error. The inventor simulated the following error of various following strategies under time-varying communication delay. During the simulation, the communication delay varying from 0.02 seconds to 0.5 seconds was applied, and the following was obtained: Figure 4In the simulation results shown, the horizontal axis represents time and the vertical axis represents the following vehicle error. It can be seen that the solution of the present invention that can adaptively adjust the number of following vehicles according to the communication delay is better than the solution that only supports a fixed following vehicle strategy. The present invention can achieve the minimum following vehicle error in the whole process.

[0053] See below for details Figure 5 To illustrate the process of driving control when a vehicle (hereinafter referred to as the vehicle) adopts the following strategy of following n vehicles:

[0054] The vehicle is based on the dynamic information u1 of the first vehicle and the corresponding dynamic transfer function θ i-1 , Θ i-2 ,…,Θ i-n The value of (multiplying the two) calculates the dynamic information u of the vehicle before 1 to n vehicles i-1 、u i-2 、…、u i-n , that is u i-n (s)=u1Θ i-n ;

[0055] Dynamic information u of the first 1 to n vehicles i-1 、u i-2 、…、u i-n Through the communication delay transfer function D conversion (the communication delay transfer function will calculate the corresponding communication delay coefficient, the dynamic information u i-1 、u i-2 、…、u i-n After multiplying by the corresponding communication delay coefficient to correct the influence of communication delay on dynamic information, we can get That is, in the Laplace domain Dynamic information of the first vehicle u i-1 The position information of the preceding vehicle is obtained by converting the vehicle kinematics conversion function in the vehicle kinematics module. i-1 、The vehicle's location information q i And the expected driving distance calculation following error f i ;

[0056] Driving control parameter K is calculated based on and f i Calculate and get the control output ξ i ,in,

[0057] According to the inverse transformation function H of the driving distance function -1 and control output ξ i Calculate the dynamic information u used to control the vehicle i , calculated as u i =ξ i*H -1 Preferably, the dynamic information used includes acceleration; if the following strategy remains unchanged, the position information q of the leading vehicle will be calculated based on the dynamic information of the vehicle through the vehicle kinematics conversion function G. i-1 、The vehicle's location information q i , and the following error f is obtained based on the expected vehicle spacing obtained from the vehicle spacing function H i , used to adjust the control output for driving control to reduce the following vehicle error.

[0058] According to one embodiment of the present invention, the present invention discloses a vehicle supporting cooperative adaptive cruise control, the vehicle comprising: a communication unit, for acquiring dynamic information of the first vehicle in the convoy and dynamic information of the vehicle preceding the vehicle, and transmitting the dynamic information of the vehicle to the vehicle behind the vehicle in the convoy; a following strategy analysis module, for determining the following reference information of the vehicle under a plurality of preset following strategies according to the dynamic information of the first vehicle in the convoy, the dynamic information of the vehicle preceding the vehicle, and the transfer function of the dynamics of each vehicle and the first vehicle, the following reference information comprising driving control parameters and relationship curves of the vehicle under a plurality of communication delays in each following strategy, the relationship curve comprising the minimum driving distance required to meet driving stability under a plurality of communication delays; a controller, for selecting an optimal following strategy according to the communication delay of the vehicle and the following reference information, and calculating a control output for driving control according to the driving control parameters corresponding to the communication delay of the vehicle in the selected optimal following strategy to dynamically adjust the driving distance, and calculating a following error according to the position information of the preceding vehicle and the position information of the vehicle, and adjusting the control output for driving control to reduce the following error.

[0059] According to one embodiment of the present invention, the controller includes a control module, an inverse transformation module for driving distance, a vehicle kinematics module, and a following error module. Preferably, the control module is used to adjust the following strategy of the vehicle in real time. The following strategy is selected and adjusted in real time according to the size of the input communication delay. Different following strategies correspond to different numbers of inputs, and the driving control parameters change accordingly. Preferably, the inverse transformation module for driving distance is used to convert the control output based on the inverse transformation function of the driving distance function to obtain dynamic information for controlling the vehicle, such as acceleration. Preferably, the vehicle kinematics module is used to convert the dynamic information and position information of the vehicle based on the conversion function of the vehicle kinematics. Preferably, the following error module is used to calculate the error or deviation (i.e., the following error) between the measured driving distance between vehicles and the expected driving distance.

[0060] According to one embodiment of the present invention, the control process after the following vehicle strategy is adjusted is as follows: Figure 6As shown, the kinematic information of the vehicle and the following error required under the following strategy are used as inputs of the control module, and the control module calculates the control output according to the required kinematic information of the vehicle and the following error. The control output is converted into dynamic information for driving control by the inverse transformation function of the vehicle spacing function in the inverse transformation module, and output, so as to control the driving of the vehicle; in addition, the dynamic information is converted into position information by the vehicle kinematic module based on the conversion function of the vehicle kinematics, and the following error is calculated by the following error module according to the expected driving distance, the position information of the preceding vehicle and the position information of the own vehicle, and the control module adjusts the driving control parameters according to the following error, and outputs the adjusted control output, and the control output is converted into dynamic information for driving control by the inverse transformation function of the vehicle spacing function in the inverse transformation module, and output, so as to adjust the driving of the vehicle.

[0061] It should be noted that although the above describes the various steps in a specific order, it does not mean that the various steps must be executed in the above specific order. In fact, some of these steps can be executed concurrently or even in a different order as long as the required functions can be achieved.

[0062] The present invention may be a system, a method and / or a computer program product. The computer program product may include a computer-readable storage medium carrying computer-readable program instructions for causing a processor to implement various aspects of the present invention.

[0063] Computer readable storage medium can be a tangible device that holds and stores instructions used by an instruction execution device. Computer readable storage medium can include, for example, but is not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination thereof. More specific examples (non-exhaustive list) of computer readable storage medium include: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a static random access memory (SRAM), a portable compact disk read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanical encoding device, for example, a punch card or a protruding structure in a groove on which instructions are stored, and any suitable combination thereof.

[0064] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A method for vehicle cooperative adaptive cruise control, wherein the vehicles form a fleet through a wireless network, characterized in that: The method comprises: Obtaining dynamic information of the first vehicle in the convoy and dynamic information of the vehicle preceding the vehicle; According to the dynamic information of the first vehicle in the convoy, the dynamic information of the vehicle before the vehicle, and the dynamic transfer function between each vehicle and the first vehicle, the following reference information of the vehicle under the preset multiple following strategies is determined, the following reference information includes the driving control parameters and relationship curves of the vehicle under multiple communication delays in each following strategy, the relationship curve includes the minimum driving distance required to meet the driving stability under multiple communication delays, the multiple following strategies are N following strategies, wherein the following strategy of following n vehicles means the strategy of the vehicle following the n vehicles in front, and the driving control needs to be performed with reference to the dynamic information of the n vehicles in front, wherein 1≤n≤N, n and N are both integers; According to the communication delay of the vehicle and the following vehicle reference information, the optimal following vehicle strategy is selected, and the control output for driving control is calculated according to the corresponding driving control parameters.

2. The method according to claim 1, characterized in that: The relationship curve corresponding to each following strategy is obtained in the following manner: According to the preset communication delay solution range and the predetermined step length, the predetermined step length is gradually increased from the initial communication delay to analyze the driving control parameters under the corresponding communication delay in the communication delay solution range; According to the corresponding communication delay and the corresponding driving control parameters, the minimum driving distance required for the corresponding communication delay to meet the driving stability is calculated.

3. The method according to claim 1 or 2, characterized in that: The driving control parameters corresponding to each following strategy at the corresponding communication delay are obtained by minimizing the infinite norm of the dynamic transfer function in the algebraic Riccati equation based on the delay in the current vehicle's control execution, the corresponding communication delay, and the dynamic transfer function under the following strategy.

4. The method according to claim 3, characterized in that The corresponding dynamic transfer function when the corresponding vehicle adopts the following strategy of following n vehicles is expressed as: Among them, u i (s) represents the dynamic information of vehicle i, u1(s) represents the dynamic information of the first vehicle in the convoy, K fb (s) represents the feedback control parameter, G i (s) represents the transfer function of vehicle kinematics, q i (s) represents the position information, τ i represents the internal delay of vehicle i, represents the time delay of vehicle i to execute control, H -1 represents the inverse transformation function of the vehicle spacing function H. The vehicle spacing function H is expressed in the Laplace domain as H(s)=hs+1, where h represents the reserved safety spacing, and K ff，i-1 Represents Θ i-1 The corresponding feedforward control parameter, K ff，i-2 Represents Θ i-2 The corresponding feedforward control parameter, K ff，i-n Represents Θ i-n The corresponding feedforward control parameter, D(s), represents the communication delay transfer function, D(s) = e -θs , e represents the base of natural logarithm, θ represents the communication delay, and the letter followed by (s) indicates that the corresponding function is analyzed in the Laplace domain, and s represents the Laplace operator.

5. The method according to claim 1, characterized in that The optimal following strategy is selected as follows: According to the communication delay of the vehicle, the following strategy corresponding to the minimum driving distance at the communication delay is determined based on the reference relationship of multiple following strategies, and is used as the optimal following strategy.

6. The method according to claim 1, characterized in that The driving control of the vehicle according to the optimal following strategy includes: When the originally adopted following strategy is different from the optimal following strategy, the dynamic information referenced by the driving control and the driving distance between the own vehicle and the preceding vehicle are switched according to the optimal following strategy.

7. The method according to claim 1, characterized in that The communication delay of the vehicle is an estimated communication delay, and the information referred to for estimating the communication delay includes transmission power information of the communication unit of the relevant vehicle, signal-to-noise ratio, vehicle spacing change information between vehicles, or a combination thereof.

8. A vehicle supporting cooperative adaptive cruise control, for executing the method according to any one of claims 1 to 7, the vehicle comprising: A communication unit, used to obtain the dynamic information of the first vehicle in the convoy and the dynamic information of the vehicle preceding the vehicle, and transmit the dynamic information of the vehicle to the vehicle behind the vehicle in the convoy; A vehicle following strategy analysis module is used to determine the vehicle following reference information of the vehicle under multiple preset vehicle following strategies based on the dynamic information of the first vehicle in the convoy, the dynamic information of the vehicle before the vehicle, and the dynamic transfer function between each vehicle and the first vehicle. The vehicle following reference information includes the driving control parameters and relationship curves of the vehicle under multiple communication delays in each vehicle following strategy. The relationship curve includes the minimum driving distance required to meet driving stability under multiple communication delays. The controller selects an optimal following strategy according to the communication delay of the vehicle and the following reference information, calculates the control output for driving control according to the driving control parameters corresponding to the communication delay of the vehicle in the selected optimal following strategy, and calculates the following error according to the position information of the leading vehicle and the position information of the vehicle and adjusts the control output for driving control.

9. An electronic device, characterized in that: include: one or more processors; as well as A memory, wherein the memory is used to store executable instructions; The one or more processors are configured to implement the steps of the method of any one of claims 1 to 7 by executing the executable instructions.

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