A multi-dimensional cooperative control method and system for heterogeneous vehicle platooning following

Abstract

The application discloses a kind of multi-dimension collaborative control method and system of heterogeneous vehicle platoon following, including the highest driving speed control of queue based on power assembly peak output power and vehicle state.The highest driving acceleration control of queue based on power assembly peak output torque and vehicle state.Heterogeneous vehicle brake pressure control based on brake system performance difference and vehicle state.Steering dynamic speed control based on the difference of heterogeneous vehicle yaw, roll stability and road curvature.Based on the above control, the driving dynamic performance of the preceding vehicle is limited, and the following vehicle will control the driving, braking and steering system of the vehicle according to the control instruction of the preceding vehicle, and make real-time adjustment according to the road condition information and vehicle distance.The application solves the limitation of the early vehicle platoon following technology for homogeneous vehicles, and coordinates heterogeneous vehicles according to vehicle state and system performance, ensuring the consistency of the queue, driving safety and turning stability during the platoon following process of heterogeneous vehicles.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of intelligent automobile multi-vehicle platoon control, and particularly relates to a multi-dimensional cooperative control method and system for platoon following of heterogeneous vehicles. BACKGROUND

[0002] In the field of intelligent networked vehicles, when multiple vehicles are traveling to the same destination, the first vehicle (the head vehicle) in the platoon following can be in manual driving or automatic driving mode, and the vehicles behind the second vehicle are all in automatic driving mode. Through perception technology and network communication technology, the geographical position information and motion information of each vehicle are obtained and transmitted, so that the vehicles in the platoon can travel in a platoon state within a safe distance. The orderly driving platoon does not need to consider the reaction time of the driver, can shorten the following distance, and improve the traffic efficiency. There is no problem of driver's line of sight obstruction caused by the large size of commercial vehicles, which reduces sudden accidents and saves a large amount of human resources while reducing the labor intensity of the driver. Multi-vehicle platoon following can greatly reduce the air resistance of the following vehicles during driving, achieving energy saving and emission reduction.

[0003] Due to the limitations of the prior art, the research on platoon control mostly assumes that the vehicles in the platoon have homogeneous properties, that is, the platoon control is performed on vehicles of the same type, and it is considered that the vehicles have the same driving state. However, in actual situations, the vehicles in the platoon have obvious heterogeneous properties, which are embodied in: different vehicle types such as sedans, trucks, and buses, different power structures such as fuel vehicles, pure electric vehicles, and hybrid vehicles, different braking systems, steering mechanisms, and suspension anti-roll mechanisms, and time-varying factors caused by changes in mass and road slope. If only homogeneous vehicle platoons are considered, the modeling and control method of the system will inevitably fail to reflect the heterogeneous system characteristics of the platoon in actual situations. The performance differences of the functional assemblies of the vehicles lead to inconsistent responses of the following vehicles to the driving instructions of the leading vehicle. For example, differences in the mass or power system performance of the front and rear vehicles will lead to inconsistent acceleration responses, resulting in inconsistent following distances and easy mixing with other vehicles. Differences in the mass or braking system performance of the front and rear vehicles will lead to inconsistent braking responses, inconsistent following distances, and affect comfort, or cause rear-end collisions. Differences in the structure or steering ability of the vehicles will lead to different lateral stability performance, and will cause the less capable rear vehicles to roll, spin, or slide. Inconsistent performance during the platoon following of heterogeneous vehicles can lead to a series of safety problems and affect the handling stability and comfort of the following vehicles.

[0004] Therefore, there is an urgent need for a multi-dimensional cooperative control method and system for platoon following of heterogeneous vehicles, so that heterogeneous vehicles with the same target endpoint can follow in a coordinated, smooth, and orderly manner.

[0005] In order to facilitate the description of the content of the present application, first of all, some concepts need to be explained. Heterogeneous vehicles are a group of platoon vehicles with obvious differences in power, braking, steering or vehicle parameters. SUMMARY

[0006] The purpose of the present application is to provide a multi-dimensional cooperative control method and system for heterogeneous vehicle platoon following to improve the above-mentioned defects of the prior art. In order to achieve the above-mentioned purpose, the method mainly includes the following steps:

[0007] S1: platoon maximum driving speed control based on powertrain peak output power and vehicle state.

[0008] S2: platoon maximum driving acceleration control based on powertrain peak output torque and vehicle state.

[0009] S3: heterogeneous vehicle brake pressure control based on brake system performance difference and vehicle state.

[0010] S4: steering dynamic speed control based on heterogeneous vehicle yaw, roll stability difference and road curvature.

[0011] S5: based on the above adjustment, the driving dynamic performance of the front vehicle is limited, and the rear vehicle will control the driving, braking and steering system of the vehicle according to the front vehicle control instruction, and make real-time adjustment according to the road condition information and vehicle distance.

[0012] Preferably, the maximum speed of the platoon vehicle is limited according to the difference in power system performance: due to the difference in powertrain of heterogeneous vehicles, the maximum speed of different vehicles is inconsistent, if the maximum speed of the front vehicle is large and no limit is added, it will lead to the rear vehicle unable to follow the front vehicle, the driving distance gradually increases, and it is easy to mix with other social vehicles, which destroys the coordination and consistency of the platoon, so the maximum speed needs to be calibrated according to the power performance and related parameters of the heterogeneous vehicle. Assuming that n heterogeneous vehicles are platoon following, the maximum driving speed u can be limited according to the following formula t max :

[0013]

[0014] Wherein, n is the number of heterogeneous vehicles in the platoon; P n e is the peak power of the heterogeneous vehicle; m n is the load of the heterogeneous vehicle; G n =m n g, wherein g is the acceleration of gravity; i n is the driving slope, which is assumed to be consistent when driving on the same section; f n is the rolling resistance coefficient, which is assumed to be consistent when driving on the same section; η nT is the mechanical efficiency of the transmission system of the heterogeneous vehicle; A nis the wind area of the heterogeneous vehicle; C n D is the air resistance coefficient, the rear vehicle has smaller air resistance, and the related coefficient can be set to reduce the weight; u n is the current vehicle speed; δ n is the rotational mass conversion coefficient of the heterogeneous vehicle. Its meaning is that in a specific working condition, the speed of the vehicle with the highest driving speed in the queue is taken as the queue speed extreme value.

[0015] According to the queue speed extreme value, the speed range of the power system of the heterogeneous vehicle in the queue is limited to avoid the driving speed exceeding the extreme value.

[0016]

[0017] wherein n is the number of the heterogeneous vehicle in the queue; n n max is the rotational speed limit value of the heterogeneous vehicle; i n g is the transmission ratio of the heterogeneous vehicle; i n 0 is the main reducer transmission ratio of the heterogeneous vehicle; r n is the rolling radius of the driving wheel of the heterogeneous vehicle; κ is the stability margin coefficient to ensure normal driving and avoid speed fluctuations, which can be taken as 1-1.05.

[0018] Preferably, the maximum acceleration of the queue vehicle is limited according to the performance difference of the power system: due to the difference of the power system of the heterogeneous vehicle, the acceleration ability of the heterogeneous vehicle in the queue is different, if the acceleration of the vehicle in the queue is not limited, it will lead to poor queue speed consistency or vehicle spacing fluctuation problem, even the rear vehicle cannot follow the front vehicle, then the maximum acceleration a t max of the heterogeneous vehicle in the queue is limited according to the peak torque of the power system of the heterogeneous vehicle and the state parameters of the vehicle.

[0019]

[0020] wherein n is the number of the heterogeneous vehicle in the queue; T n tq is the peak torque of the heterogeneous vehicle; α n is the slope angle of the driving section of the heterogeneous vehicle; du n / dt is the maximum acceleration of the heterogeneous vehicle; the meanings of the remaining parameters are the same as above. Its meaning is that in a specific working condition, the acceleration of the vehicle with the weakest acceleration performance in the queue is taken as the queue acceleration extreme value.

[0021] According to the queue acceleration extreme value, the range of the throttle opening degree of the power system of the heterogeneous vehicle in the queue (oil vehicle) or the range of the output voltage of the motor controller (electric vehicle) is limited to avoid the acceleration of part of the vehicle being too high, which leads to the rear vehicle unable to follow. The power output coefficient is calculated according to the following formula.

[0022]

[0023] Wherein, n is the number of heterogeneous vehicles in the queue; The stability margin coefficient is taken as 1-1.05 to ensure normal torque requirements and avoid insufficient acceleration. θ n The heterogeneous vehicle power output coefficient is 0-1, and the throttle opening range (for gasoline vehicles) or the motor controller output voltage range (for electric vehicles) can be calculated according to the power output coefficient.

[0024] U n N = θ n U n max

[0025] Wherein, U n N is the limit value of the throttle opening range (for gasoline vehicles) or the motor controller output voltage range (for electric vehicles); U n max is the original maximum throttle opening (for gasoline vehicles) or the peak output voltage of the motor controller.

[0026] Preferably, the braking force limitation and distribution according to the differences in braking system performance and vehicle state: due to the differences in braking system performance of heterogeneous vehicles or the different vehicle states, the deceleration or comfort during braking of heterogeneous vehicles differs greatly, and in extreme braking conditions, the braking lock of individual vehicles needs to be considered, therefore, under the premise of ensuring driving distance and avoiding braking skidding, tailing and other braking safety phenomena, the braking comfort is considered.

[0027] When a dangerous situation occurs and emergency braking is needed, the maximum theoretical braking intensity can be equal to the road adhesion coefficient, i.e. which can ensure the maximum braking efficiency of the whole vehicle. When it is not an emergency, the braking acceleration should be limited to meet the comfort and stability of heterogeneous vehicles carrying different functions. Generally, the braking deceleration should not be greater than 1.5-2.5 m / s 2 , otherwise it will not only make passengers feel uncomfortable or dangerous, cause unsafe goods, but also increase fuel consumption and tire wear. Therefore, the braking intensity under different conditions is determined

[0028]

[0029] Wherein, z t is the target braking intensity of the queue; d n is the braking deceleration limit value required by heterogeneous vehicles for comfort. According to the braking intensity, the accurate distribution of the front and rear wheel braking forces F nμ1 and F nμ2 of heterogeneous vehicles is completed:

[0030]

[0031] Wherein, a nis the distance from the center of mass of the heterogeneous vehicle to the front axle centerline; b n is the distance from the center of mass of the heterogeneous vehicle to the rear axle centerline; z t is the braking strength of the heterogeneous vehicle queue; h n g is the height of the center of mass of the heterogeneous vehicle; L n is the wheelbase of the heterogeneous vehicle; the meanings of the remaining parameters are described above. However, when the partial wheel braking cylinder pressure is insufficient to meet the ideal braking strength requirement, the braking strength, braking force distribution of the single vehicle, and the braking deceleration of the queue need to be adjusted according to the above formula to avoid the phenomenon of partial vehicle braking lock or rear-end collision due to different braking decelerations.

[0032] Preferably, the steering response control needs to be performed according to the differences in the yaw and roll stability of the heterogeneous vehicles and the road curvature. During high-speed turning, not only the lateral slip caused by reaching the lateral force limit needs to be considered, but also the occurrence of roll is possible. In order to guarantee the yaw and roll stability of the heterogeneous vehicle queue during the following process, the vehicle speed during turning needs to be coordinated and controlled.

[0033] First, the lateral vehicle speed at the vertex of the curve (the place with the maximum road curvature) is controlled according to the state parameters of the heterogeneous vehicle before turning and the curve road information, the side slip angle of the center of mass is reduced, and the occurrence of lateral slip is avoided. The lateral vehicle speed v n i at the vertex of the curve is calculated as follows: e The lateral vehicle speed v

[0034]

[0035] where h is the distance from the center of mass of the vehicle to the center of road curvature, and θ is the included angle between the vehicle speed and the line connecting the center of mass of the vehicle to the center of road curvature. Then, the heterogeneous steering angle and the braking torque of each wheel are controlled, so that the queue generates a braking deceleration z t parallel to the normal of the vertex of the curve and with a size of z y , so that the lateral speed v i of the queue vehicle at the place with the maximum curvature is reduced to zero, and the side slip angle of the center of mass is idealized to 0, so as to guarantee the stability of turning driving.

[0036]

[0037] where v zl is the driving speed of the heterogeneous vehicle, and μ is the road adhesion coefficient. In addition, the longitudinal vehicle speed at the vertex of the curve (the place with the maximum road curvature) is controlled according to the state parameters of the heterogeneous vehicle before turning and the curve road information, so as to avoid the occurrence of tire grounding deterioration or roll instability caused by too fast speed. Usually, the difference between the tire vertical forces F zr and F zl generated by the roll movement of the vehicle, i.e., the roll index R, is used for measurement, and the roll index R is calculated based on the roll dynamics

[0038]

[0039] wherein, l w is the wheel track of the vehicle; l s is the lateral distance between the left and right suspensions of the vehicle; h R is the height of the vehicle's center of mass from the roll center; a y is the lateral acceleration; and φ is the roll angle of the sprung mass of the vehicle. When the roll angle is small, the above formula can be simplified as,

[0040]

[0041] Finally, due to the differences in types, the heterogeneous vehicles have different requirements for the degree of roll. According to the differences in the roll coefficients of the heterogeneous vehicles and the differences in the related vehicle parameters, the longitudinal speed v t x of the platoon vehicles passing through the maximum curvature can be limited,

[0042]

[0043] wherein, k is the road curvature; R h threshold is the roll limit of the heterogeneous vehicle; l nw is the wheel track of the heterogeneous vehicle; h nR is the height of the center of mass of the heterogeneous vehicle from the roll center.

[0044] The front wheel steering angle and the tire braking force of the heterogeneous vehicle are controlled in combination with the lateral and longitudinal speed requirements of the platoon.

[0045] The application also provides a multi-dimensional cooperative control system for platoon following of heterogeneous vehicles, which comprises a roadside road information acquisition and transmission module (RSU), a vehicle-end information receiving module (OBU), a heterogeneous vehicle vehicle-to-vehicle communication module (V2V), a vehicle state information acquisition module, a cloud computing module, and an action execution module of each heterogeneous vehicle.

[0046] The roadside road information acquisition and transmission module (RSU) is erected on both sides of the road and is responsible for acquiring the road curvature k and the slope angle a n of the driving section of the heterogeneous vehicle, and acquiring the road adhesion condition according to the previous driving experience, monitoring the traffic congestion state or the sudden event of the road section.

[0047] The vehicle-end information receiving module (OBU) is installed at the vehicle end, interacts with the roadside road information acquisition and transmission module (RSU) in real time, acquires the related road information, and transmits the information to the vehicle control unit, which is transmitted to the cloud computing module.

[0048] The heterogeneous vehicle vehicle-to-vehicle communication module (V2V) is installed at the vehicle end and is responsible for the information interaction between the platoon vehicles and the transmission of the action instructions between the vehicles.

[0049] The vehicle state information acquisition module: installed at the vehicle end, acquires various heterogeneous vehicle performance and state information required for multi-dimensional cooperative control, and transmits the information to the cloud computing module by the whole vehicle control unit, and the related information includes: peak power P n e of the heterogeneous vehicle n Mechanical efficiency η nT of the heterogeneous vehicle transmission system n Windward area A n D of the heterogeneous vehicle n Air resistance coefficient C n of the heterogeneous vehicle n tq Current speed u n of the heterogeneous vehicle n Peak torque T h threshold of the heterogeneous vehicle nw Maximum acceleration du nR / dt of the heterogeneous vehicle n max Rolling limit R n g of the heterogeneous vehicle n 0 Track l n of the heterogeneous vehicle n N Height h n of the heterogeneous vehicle mass center to the front axle center line n Distance b n g of the heterogeneous vehicle mass center to the rear axle center line n Height h nw of the heterogeneous vehicle mass center nR ;

[0050] The cloud computing module: as an integrated computing unit, integrates road condition information and heterogeneous vehicle performance and state parameters, and transmits the action limit value of the queue driving to each heterogeneous vehicle in the queue according to the built-in multi-dimensional cooperative control algorithm of the above-mentioned heterogeneous vehicle platoon following.

[0051] The action execution module of the heterogeneous vehicle: according to the action limit value calculated by the cloud computing module received by the vehicle, the driving, braking and steering execution systems are coordinated and controlled, so as to ensure the smooth and orderly platoon following driving.

[0052] The beneficial effects of the present application are:

[0053] (1) The method overcomes the limitation of the previous vehicle platoon following technology for homogeneous vehicles, and coordinates the driving process of heterogeneous vehicles according to the vehicle state and system performance, thereby ensuring the queue consistency, driving safety and turning stability during the platoon following process of heterogeneous vehicles.

[0054] (2) Compared with the unmanned vehicle technology, the safe and reliable heterogeneous vehicle platoon following technology has lower requirements for hardware devices and intelligent algorithms, greatly reduces the cost investment, has great practical value and high social and economic benefits.

[0055] (3) The present application relates to a multi-dimensional cooperative control system for heterogeneous vehicle platoon following, which provides equipment support for the implementation of heterogeneous vehicle platoon following technology, promotes the development of intelligent networked vehicle technology, and has better real-time performance and robustness than the platoon technology based on self-sensor ranging and target recognition.

[0056] (4) Heterogeneous vehicle platoon following helps to combine heterogeneous vehicles with the same destination in real time, which is beneficial to alleviate traffic congestion, reduce driver fatigue and reduce energy consumption. BRIEF DESCRIPTION OF DRAWINGS

[0057] Figure 1 Multi-dimensional cooperative control architecture diagram of heterogeneous vehicle platoon following.

[0058] Figure 2 Schematic diagram of heterogeneous vehicle platoon following.

[0059] Figure 3 Maximum driving speed control of heterogeneous vehicle platoon following.

[0060] Figure 4 Maximum driving acceleration control of heterogeneous vehicle platoon following.

[0061] Figure 5 Deceleration braking control of heterogeneous vehicle platoon following.

[0062] Figure 6 Curve speed control of heterogeneous vehicle platoon following based on road information.

[0063] Figure 7 Schematic diagram of dynamic control of heterogeneous vehicle platoon following through a curve. DETAILED DESCRIPTION

[0064] The present application provides a multi-dimensional cooperative control method and system for heterogeneous vehicle following. In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described below in combination with the drawings and embodiments. However, the protection scope of the present application is not limited thereto. The present application is based on the following technical scheme: Figure 1The multi-dimensional cooperative control architecture diagram of the heterogeneous vehicle platoon follow-up is shown to be implemented, and the heterogeneous vehicle platoon follow-up schematic diagram is shown Figure 2 .

[0065] Step 1: Limit the maximum vehicle speed of the platoon according to the performance difference of the power system. Due to the difference in powertrain of heterogeneous vehicles, the maximum speed of different vehicles is inconsistent. If the maximum speed of the front vehicle is large and no limit is added, it will lead to the rear vehicle unable to follow the front vehicle, the distance between vehicles gradually increases, and it is easy to mix with other social vehicles, which destroys the coordination and consistency of the platoon. Therefore, the maximum speed needs to be calibrated according to the power performance and related parameters of the heterogeneous vehicle. The process is shown in Figure 3 , assuming that n vehicles are platoon following, the maximum driving speed u can be limited according to the following formula t max :

[0066]

[0067] , wherein n is the number of heterogeneous vehicles in the platoon; P n e is the peak power of the heterogeneous vehicle; m n is the load of the heterogeneous vehicle; G n = m n g, wherein g is the acceleration of gravity; i n is the driving slope, which is assumed to be consistent when driving on the same section; f n is the rolling resistance coefficient, which is assumed to be consistent when driving on the same section; η n T is the mechanical efficiency of the transmission system; A n is the wind area of the heterogeneous vehicle; C D n is the air resistance coefficient, the wind resistance of the rear vehicle is smaller, and the related coefficient can be set to reduce the weight; u n is the current speed; δ n is the rotational mass conversion coefficient of the heterogeneous vehicle. Its meaning is that the speed of the vehicle with the smallest maximum driving speed in the platoon is taken as the extreme value of the platoon speed under certain working conditions.

[0068] According to the extreme value of the platoon speed, the speed range of the power system of the heterogeneous vehicle in the platoon is limited to avoid the driving speed exceeding the extreme value.

[0069]

[0070] , wherein n is the number of heterogeneous vehicles in the platoon; n n max is the speed limit value of the power system of the heterogeneous vehicle; i n g is the transmission ratio of the heterogeneous vehicle; i n 0 is the main reducer transmission ratio of the heterogeneous vehicle; r n is the rolling radius of the driving wheel of the heterogeneous vehicle; κ is the stability margin coefficient to ensure normal driving and avoid speed fluctuation, which can be taken as 1-1.05.

[0071] Step 2: Limit the maximum acceleration of the platoon vehicle according to the difference in power system performance. Due to the difference in powertrain of heterogeneous vehicles, the acceleration ability of the platoon heterogeneous vehicle is different. If the acceleration of the vehicle in the platoon is not limited, it will lead to poor consistency of the platoon speed or fluctuation of the vehicle spacing, or even the situation that the rear vehicle cannot follow the front vehicle. Then, according to the steps shown in the figure, the maximum acceleration a Figure 4 of the platoon heterogeneous vehicle is limited according to the peak torque of the power system of the heterogeneous vehicle and the state parameters of the vehicle. t max

[0072]

[0073] wherein n is the number of the heterogeneous vehicle in the platoon; T n tq is the peak torque of the heterogeneous vehicle; a n is the slope angle of the driving section of the heterogeneous vehicle; du n / dt is the maximum acceleration of the heterogeneous vehicle; and the remaining parameters have the same meaning as above. The meaning is that the acceleration of the weakest vehicle in the platoon is taken as the acceleration extreme value of the platoon under certain conditions.

[0074] According to the acceleration extreme value of the platoon, the throttle opening range (for gasoline vehicles) or the output voltage range of the motor controller (for electric vehicles) of the power system of the heterogeneous vehicle in the platoon is limited to avoid the acceleration of some vehicles being too high, which leads to the rear vehicle being unable to follow.

[0075] The power output coefficient is calculated according to the following formula.

[0076]

[0077] wherein n is the number of the heterogeneous vehicle in the platoon; and is the stability margin coefficient, which is taken as 1-1.05 to ensure normal torque requirements and avoid insufficient acceleration; a n is the power output coefficient of the heterogeneous vehicle (0-1), which can be used to calculate the throttle opening range (for gasoline vehicles) or the output voltage range of the motor controller (for electric vehicles)

[0078] U n N = a n max

[0079] wherein U n N is the limit value of the throttle opening range (for gasoline vehicles) or the output voltage range of the motor controller (for electric vehicles) of the power system of the heterogeneous vehicle; and U n max is the original maximum opening of the throttle (for gasoline vehicles) or the peak output voltage of the motor controller.

[0080] ​Step 3: Braking force limitation and distribution according to braking system performance difference and vehicle state. Due to the difference in braking system performance of heterogeneous vehicles or the difference in vehicle state, the deceleration or comfort of heterogeneous vehicles during braking is quite different. In extreme braking conditions, the braking lock of individual vehicles needs to be considered, and the braking comfort is considered on the premise of ensuring the driving distance, avoiding braking sideslip, and tailing phenomenon to ensure braking safety.

[0081] When a dangerous situation occurs and emergency braking is needed, the maximum braking strength can theoretically equal the road adhesion coefficient, i.e. which can guarantee the maximum braking efficiency of the whole vehicle. When non-emergency situations occur, the braking speed should be limited to meet the comfort and stability of heterogeneous vehicles carrying different functions. Generally, the braking deceleration should not be greater than 1.5-2.5 m / s 2 , otherwise it will not only make passengers feel uncomfortable or dangerous or cause unsafe goods, but also increase fuel consumption and tire wear. Therefore, according to the steps shown in Figure 5 , the braking strength under different conditions is determined:

[0082]

[0083] where z t is the target braking strength of the queue; d n is the braking deceleration limit value required by the comfort of heterogeneous vehicles. According to the braking strength, the accurate distribution of the front and rear wheel braking forces F nμ1 and F nμ2 of heterogeneous vehicles is completed:

[0084]

[0085] where a n is the distance from the center of mass of the heterogeneous vehicle to the front axle centerline; b n is the distance from the center of mass of the heterogeneous vehicle to the rear axle centerline; z t is the braking strength of the heterogeneous vehicle queue; h n g is the height of the center of mass of the heterogeneous vehicle; L n is the wheelbase of the heterogeneous vehicle; and the meanings of the remaining parameters are referred to the above. When the wheel cylinder pressure of some wheels is insufficient to meet the ideal braking strength requirement, the braking strength of the individual vehicle, the braking force distribution, and the braking deceleration of the queue need to be adjusted according to the above formula to avoid the braking lock of some vehicles or the rear-end phenomenon caused by the difference in braking deceleration.

[0086] Step 4: Steering response control according to the difference in yaw and roll stability of heterogeneous vehicles and road curvature. During high-speed turning, not only the lateral slip caused by reaching the lateral force limit needs to be considered, but also the occurrence of roll may occur. To ensure the yaw and roll stability of heterogeneous vehicles during platooning, the steering response control can be performed according toFigure 6 The steps shown demonstrate how to coordinate and control the vehicle speed during the turning process.

[0087] First, based on the vehicle's state parameters before turning and the road information, the lateral speed at the apex of the curve (where the road curvature is greatest) is controlled to reduce the center of gravity sideslip angle and prevent lateral slippage. Figure 7 As shown, based on road information and vehicle speed v i Calculate the time T to reach the apex of the curve. e As shown in the following formula,

[0088]

[0089] Where h is the distance from the vehicle's center of mass to the center of road curvature; Θ is the angle between the vehicle's speed and the line connecting the vehicle's center of mass to the center of road curvature. Then, the heterogeneous steering angle and the braking torque of each wheel are controlled to create a queuing parallel to the curve's apex with a magnitude of z. t The braking deceleration causes the convoy vehicles to reach the lateral velocity v at the point of maximum curvature. y The angle is reduced to zero, making the center of gravity sideslip angle ideally 0, in order to ensure the stability of cornering and avoid lateral slippage.

[0090]

[0091] Among them, v i denoted as , where μ is the vehicle's speed and is the road adhesion coefficient. Furthermore, based on the vehicle's state parameters before turning and road information, the longitudinal speed at the apex of the curve (the point of maximum road curvature) is controlled to prevent excessive speed from causing poor tire contact or even roll instability. Typically, the vertical tire force F generated by the vehicle's roll motion is used as the metric. zl and F zr The difference between them is measured by the rollover index R, and is calculated based on roll dynamics.

[0092]

[0093] Among them, l w The wheelbase of the vehicle; l s h is the lateral distance between the left and right suspensions of the vehicle. R The height of the vehicle's center of gravity from the roll center; a y Let be the lateral acceleration; φ be the roll angle of the vehicle's sprung mass. When the roll angle is small, the above equation can be simplified to:

[0094]

[0095] Finally, heterogeneous vehicles have different requirements for roll due to type differences. The longitudinal speed of the platoon vehicles through the maximum curvature can be limited according to the differences in the roll coefficients of the heterogeneous vehicles and the differences in the related vehicle parameters,

[0096]

[0097] wherein k is the road curvature; R h threshold is the roll limit of the heterogeneous vehicle; l nw is the track of the heterogeneous vehicle; h nR is the height of the center of mass of the heterogeneous vehicle from the roll center.

[0098] The front wheel steering angle and the tire braking force of the heterogeneous vehicle are controlled in combination with the lateral and longitudinal speed requirements of the platoon.

[0099] The above series of detailed descriptions are only specific descriptions of the feasible implementation manners of the present application, and are not used to limit the protection scope of the present application. Any equivalent manners or changes without departing from the present application should be included in the protection scope of the present application.

Claims

1. A multi-dimensional cooperative control method for heterogeneous vehicle platooning and following, characterized in that, Including the following: S1: Queue maximum driving speed control based on powertrain peak output power and vehicle status; S2: Queue maximum driving acceleration control based on powertrain peak output torque and vehicle status; S3: Heterogeneous vehicle braking force control based on differences in braking system performance and vehicle status; S4: Steering dynamic speed control based on differences in yaw and roll stability of heterogeneous vehicles and road curvature; S5: By controlling the dynamic performance of the preceding vehicle through the above-mentioned control, the following vehicle will control its own drive, braking, and steering systems according to the control instructions of the preceding vehicle; The specific implementation method of S1 includes: Suppose there are n heterogeneous vehicles queuing and following each other, and the maximum speed u is limited according to the following formula. tmax : Where n is the heterogeneous vehicle number in the queue; P ne For heterogeneous vehicles, the peak power is m. n For heterogeneous vehicle loads; G n =m n g, where g is the acceleration due to gravity; i n The gradient is assumed to be consistent across the same road segment; f n η is the rolling resistance coefficient, assumed to be consistent when traveling on the same road segment; nT For the mechanical efficiency of the transmission system of heterogeneous vehicles; A n For heterogeneous vehicles, the frontal area is C. nD The drag coefficient is used because the rear vehicle has lower drag, so a correlation coefficient can be set to reduce its weight. n The current vehicle speed; δ n The rotational mass conversion factor for heterogeneous vehicles; The implementation method of S2 includes: Based on the peak torque of the heterogeneous vehicle power system and vehicle state parameters, the maximum acceleration a of the heterogeneous vehicles in the platoon is calculated. tma x is subject to restrictions: Where, n is the heterogeneous vehicle number in the queue; T ntq For heterogeneous vehicles, the peak torque is α. n For road sections with heterogeneous vehicles, the slope angle is... n / dt is the maximum acceleration of the heterogeneous vehicle; i ng For heterogeneous vehicles, the transmission ratio; i n0 For the main reducer gear ratio of heterogeneous vehicles, r n Let be the rolling radius of the drive wheel of the heterogeneous vehicle; The implementation method of S3 includes: During emergency braking, the maximum braking intensity equals the road surface adhesion coefficient; in non-emergency situations, braking acceleration is limited to ensure comfort and stability for vehicles with different functions such as cargo and passenger transport, with braking deceleration not exceeding 1.5-2.5 m / s². 2 Therefore, the braking intensity under different conditions needs to be determined. in, Z represents the road surface adhesion coefficient. t The braking intensity of the queue target; d n To determine the braking deceleration limit for the heterogeneous vehicle to meet comfort requirements, and based on the braking intensity, calculate the braking force F for the front and rear wheels of the heterogeneous vehicle. nμ1 and F nμ2 Accurate allocation: Among them, a n b is the distance from the center of mass of the heterogeneous vehicle to the center line of the front axle; n z is the distance from the center of mass of the heterogeneous vehicle to the center line of the rear axle; t For heterogeneous vehicle platoon braking intensity; h n g The height of the center of gravity of a heterogeneous vehicle; L n For heterogeneous vehicle wheelbases; The implementation method of S4 includes: S4.

1. Based on the vehicle's state parameters before turning and the road information of the curve, control the lateral speed at the apex of the curve to reduce the sideslip angle and prevent lateral slippage. This is achieved by adjusting the road information and vehicle speed v. n i Calculate the time T to reach the apex of the curve. e As shown in the following formula, Where h is the distance from the vehicle's center of mass to the center of road curvature; θ is the angle between the vehicle's speed and the line connecting the vehicle's center of mass to the center of road curvature. S4.2 Control the heterogeneous steering angle and braking torque of each wheel to create a queue parallel to the normal direction at the apex of the curve, with a magnitude of z. t The braking deceleration causes the convoy vehicles to reach the lateral velocity v at the point of maximum curvature. y Reduce it to zero, so that the sideslip angle of the center of gravity is ideally zero, to ensure stability when cornering: Among them, v i The speed of the heterogeneous vehicle is μ; the road surface adhesion coefficient is μ. S4.

3. Based on the state parameters of the heterogeneous vehicle before turning and the road information of the curve, the longitudinal speed at the apex of the curve is controlled, using the vertical tire force F generated by the vehicle's lateral tilting motion. zl and F zr The difference between them is measured by the rollover index R, and is calculated based on roll dynamics. Among them, l w The wheelbase of the vehicle; l s h is the lateral distance between the left and right suspensions of the vehicle. R The height of the vehicle's center of gravity from the roll center; a y Let be the lateral acceleration; φ be the roll angle of the vehicle's sprung mass. When the roll angle is small, the above formula can be simplified to: S4.

4. Based on the differences in rollover coefficients of heterogeneous vehicles and the variations in relevant vehicle parameters, the longitudinal velocity v of the convoy vehicles passing through the point of maximum curvature is calculated. tx To impose restrictions, Where k is the road curvature; R nthreshold For heterogeneous vehicles, the rollover limit; nw The wheelbase of heterogeneous vehicles; h nR The height of the center of gravity of the heterogeneous vehicle from the roll center.

2. The multi-dimensional cooperative control method for heterogeneous vehicle platooning according to claim 1, characterized in that, S1 further includes: limiting the rotational speed range of the power systems of heterogeneous vehicles in the queue based on the queue speed extreme value. Where n is the number of the heterogeneous vehicle in the queue; n nmax For the speed limit of heterogeneous vehicle powertrain systems; i ng For heterogeneous vehicles, the transmission ratio; i n0 The gear ratio of the main reducer for heterogeneous vehicles; r n κ is the rolling radius of the drive wheel of the heterogeneous vehicle; κ is the stability margin coefficient, which is taken as 1 to 1.05 to ensure normal driving and avoid speed fluctuations.

3. The multi-dimensional cooperative control method for heterogeneous vehicle platooning according to claim 1, characterized in that, S2 further includes: limiting the throttle opening range or the motor controller output voltage range of the power systems of heterogeneous vehicles in the queue based on the extreme value of queue acceleration, specifically calculating the power output coefficient according to the following formula: Where, θ n is the power output coefficient of heterogeneous vehicles, and n is the heterogeneous vehicle number in the queue; To ensure a stable torque margin and prevent insufficient acceleration, a value of 1 to 1.05 is used. The throttle opening range or the motor controller output voltage range is calculated based on the power output coefficient. IN nN =θ n IN nmax Among them, U nN For heterogeneous vehicle powertrain systems, this refers to the limit values ​​of the throttle opening range or the output voltage range of the motor controller; U nmax This refers to the original maximum opening of the throttle valve or the peak output voltage of the motor controller.

4. A multi-dimensional collaborative control system for heterogeneous vehicle platooning and following, characterized in that, It includes a roadside information collection and transmission module (RSU), a vehicle-to-everything (OBU) information receiving module, a vehicle-to-vehicle (V2V) communication module for heterogeneous vehicles, a vehicle status information collection module, a cloud computing module, and action execution modules for various heterogeneous vehicles. The roadside information collection and transmission module (RSU) is installed on both sides of the road and is responsible for collecting road condition information and monitoring traffic congestion or emergencies on the road section. The vehicle-mounted information receiving module (OBU) is installed on the vehicle and interacts in real time with the roadside information acquisition and transmission module (RSU) to obtain relevant road information and transmit it to the vehicle control unit. The heterogeneous vehicle-to-vehicle communication module (V2V) is installed on the vehicle and is responsible for information exchange between vehicles in the queue and transmitting action commands between vehicles. The vehicle status information acquisition module is installed on the vehicle and collects various heterogeneous vehicle status information required for multi-dimensional collaborative control. The cloud computing module, as an integrated computing unit, integrates road condition information and heterogeneous vehicle performance and status parameters. Based on the built-in heterogeneous vehicle platooning and following multi-dimensional collaborative control algorithm, it calculates the action limits of platooning and transmits them to each heterogeneous vehicle in the platoon. The algorithm built into the cloud computing module includes the multi-dimensional collaborative control method for heterogeneous vehicle platooning as described in claim 1. The heterogeneous vehicle motion execution module coordinates and controls the drive, braking, and steering systems based on the motion limits calculated by the cloud computing module received by the vehicle.

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