A vehicle platoon lateral and longitudinal cooperative control method with external disturbances, input time delays and communication delays

Abstract

This invention belongs to the field of automotive control technology and discloses a vehicle platooning lateral and longitudinal coordinated control method with external disturbances, input delays, and communication delays, comprising: S1. Establishing a vehicle platooning model: the vehicle platooning model includes a longitudinal vehicle model considering longitudinal input delays and communication delays, and a lateral vehicle model considering lateral input delays; S2. Designing a platooning lateral and longitudinal coordinated controller: the lateral and longitudinal coordinated controller includes a longitudinal controller designed based on the vehicle longitudinal model and a lateral controller designed based on the vehicle lateral model; S3. Controlling vehicle lateral and longitudinal movement through the lateral and longitudinal coordinated controller: the longitudinal controller ensures that the target following vehicle maintains the desired vehicle spacing and tracks the speed of the lead vehicle; the lateral controller controls the target following vehicle to move along the road centerline.

Description

Technical Field

[0001] This invention belongs to the field of automotive control technology, specifically relating to a vehicle platoon lateral and longitudinal coordinated control method with external disturbances, input time delays, and communication delays. Background Technology

[0002] The dramatic increase in the number of cars over the past few decades has posed significant challenges to energy security and traffic safety. According to the National Highway Traffic Safety Administration (NHTSA), approximately 84% of traffic accidents are caused by human factors. Vehicle platooning can significantly reduce traffic accidents caused by driver fatigue and misoperation, thereby improving road traffic safety. Furthermore, vehicle platooning (especially heavy truck platooning) can reduce air resistance between vehicles, thereby reducing emissions and fuel consumption and improving road capacity. It is precisely because of these potential benefits that vehicle platooning control has attracted increasing attention from scholars.

[0003] Vehicle platooning control technology mainly comprises two parts: longitudinal control and lateral control. The goal of longitudinal control is to ensure that vehicles in the platoon travel at the same speed and maintain the desired spacing between adjacent vehicles; lateral control requires vehicles in the platoon to travel along the lane centerline and avoid exceeding road boundaries. However, in actual vehicle platooning control, the information acquired by vehicles from other vehicles is often affected by communication latency, which tends to exhibit a randomly varying distribution. Furthermore, actuators may also be affected by latency when receiving control commands, leading to deviations between the executed actions and the expected timing. The presence of latency makes it difficult for vehicles to react quickly to real-time traffic conditions, resulting in increased platoon length, longer queuing times, and even traffic congestion. More importantly, the response lag caused by latency affects the speed at which vehicles can quickly adjust their driving strategies, thus exacerbating platoon instability. Latency also reduces control accuracy, causing vehicles to make decisions based on outdated or incomplete information, thereby weakening the overall control performance of the platoon. Summary of the Invention

[0004] In view of this, in order to solve the problems mentioned in the background art, the purpose of the present invention is to provide a vehicle queuing lateral and longitudinal cooperative control method with external disturbances, input time delay and communication delay.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A vehicle platoon lateral and longitudinal coordinated control method with external disturbances, input time delays, and communication delays includes the following steps:

[0007] S1. Establish a vehicle queuing model

[0008] The vehicle queuing model includes a longitudinal vehicle model that considers longitudinal input delay and communication delay, and a lateral vehicle model that considers lateral input delay.

[0009] S2. Design a horizontal and vertical coordinated controller

[0010] The longitudinal and lateral coordinated controller includes a longitudinal controller designed based on the vehicle's longitudinal model and a lateral controller designed based on the vehicle's lateral model;

[0011] S3. Control the vehicle's lateral and longitudinal movement via the lateral and longitudinal coordination controller.

[0012] The longitudinal controller ensures that the target following vehicle maintains the desired vehicle distance from the lead vehicle and tracks the speed of the lead vehicle.

[0013] The target following vehicle is controlled to move along the center line of the road by the lateral controller.

[0014] Preferably, the expression for the vehicle longitudinal model is:

[0015]

[0016] Among them, s i , a i These are the longitudinal position, velocity, and acceleration of the i-th vehicle, respectively, κ i Represents the longitudinal dynamic time constant. Indicates the longitudinal control input, t x,i (t) is the unknown bounded longitudinal input time delay of the accelerator and brake pedals. And the longitudinal input time delay t x,i The derivative of (t) is bounded above, i.e.

[0017] Preferably, the communication delay from vehicle j to vehicle i is expressed as t. ci,j ,and

[0018] Preferably, choose x i =[s i ,v i ,a i ] T As the longitudinal system state of the i-th vehicle, the following error expression for the target following vehicle tracking the speed of the lead vehicle is: Where, d i,j =[(ij)d des 00] T d des This represents the expected spacing error.

[0019] Preferably, the expression for the longitudinal controller is:

[0020]

[0021] Among them, K x,i η represents the longitudinal control gain. i-1 (tt ci ) indicates that vehicle i-1 sends observation information with communication delay to vehicle i, x0(tt) ci,0 This indicates that the navigator sends observation information with communication delay to vehicle i, where the communication delay includes communication time delay t. ci ε is a constant greater than zero and η i (t) = 0, t < 0.

[0022] Preferably, the longitudinal control gain K x,i The expression is:

[0023] K x,i =YM -1 ;

[0024]

[0025] Ψ1(1,2)=PM-αM T A T ;

[0026]

[0027]

[0028] The positive definite symmetric matrices P, Q, R, S and S, M, Y can be solved using the Yalmip toolbox in Matlab.

[0029] Preferably, the vehicle lateral model is constructed based on a two-degree-of-freedom bicycle model, and the expression of the two-degree-of-freedom bicycle model is:

[0030]

[0031] in, This represents the lateral velocity of the i-th vehicle. Represents the yaw rate of the i-th vehicle. l represents the moment of inertia about the z-axis. f,i and l r,i F represents the distance from the front and rear axles to the center of mass, respectively. i f and F i r These represent the lateral forces of the front and rear tires, respectively.

[0032] Preferably, the state-space equation of the lateral error model is:

[0033]

[0034] in, This represents the lateral positional error between the center of mass of the i-th vehicle and the lane centerline. This represents the heading error of the i-th vehicle relative to the lane centerline. Indicates lateral control input. and These represent the lateral stiffness of the front and rear tires, respectively. y,i (t) represents the unknown lateral input delay of the actuator, and

[0035] Preferably, the expression for the lateral controller is:

[0036]

[0037] in, K y,i This indicates the lateral control gain.

[0038] Preferably, the lateral control gain K y,i The expression is:

[0039] K y,i =VL -1 ;

[0040]

[0041] The matrices L > 0, R > 0, and W > 0 are solved using the Yalmip toolbox in Matlab.

[0042] Compared with the prior art, the present invention has the following advantages:

[0043] This invention constructs a decoupled control framework that includes a lateral controller and a longitudinal controller. The lateral controller ensures that vehicles can follow the center line of the road while taking into account execution delays. The longitudinal controller ensures that each following vehicle can follow the state of the lead vehicle and maintain a safe distance between adjacent vehicles while taking into account execution delays and communication delays. This effectively achieves stable formation and configuration of the convoy and allows for arbitrarily large input and communication delays during formation. Attached Figure Description

[0044] Figure 1 This is a block diagram of the lateral and longitudinal coordinated control of a commercial vehicle fleet based on the present invention;

[0045] Figure 2This is a block diagram of the lateral and longitudinal cooperative control of the i-th vehicle in a commercial vehicle fleet based on the present invention;

[0046] Figure 3 This is a schematic diagram of a two-degree-of-freedom bicycle model. Detailed Implementation

[0047] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] A vehicle platoon lateral and longitudinal coordinated control method with external disturbances, input time delays, and communication delays includes the following steps:

[0049] S1. Establish a vehicle queuing model

[0050] The vehicle queuing model includes a longitudinal vehicle model that considers longitudinal input delay and communication delay, and a lateral vehicle model that considers lateral input delay.

[0051] (11) Regarding the longitudinal model of the vehicle

[0052] The longitudinal dynamics model of the i-th vehicle in the queue is described by the following third-order linear model:

[0053]

[0054] Among them, s i , a i These are the longitudinal position, velocity, and acceleration of the i-th vehicle, respectively, κ i Represents the longitudinal dynamic time constant. Indicates the longitudinal control input, t x,i (t) is the unknown bounded longitudinal input time delay of the accelerator and brake pedals. And the longitudinal input time delay t x,i The derivative of (t) is bounded above, i.e.

[0055] use Representing the longitudinal system state of the i-th vehicle, we obtain the following:

[0056]

[0057] in,

[0058] (12) Regarding the vehicle lateral model

[0059] The vehicle lateral model is based on, for example Figure 3 The two-degree-of-freedom bicycle model shown is constructed as follows, and the expression of the two-degree-of-freedom bicycle model is:

[0060]

[0061] in, This represents the lateral velocity of the i-th vehicle. Represents the yaw rate of the i-th vehicle. l represents the moment of inertia about the z-axis. f,i and l r,i F represents the distance from the front and rear axles to the center of mass, respectively. i f and F i r These represent the lateral forces of the front and rear tires, respectively.

[0062] Assuming the tire operates in a linear region, meaning the tire lateral force can be calculated using a small-angle approximation method:

[0063]

[0064] in, and δ represents the lateral stiffness of the front and rear tires, respectively. i Indicates the steering angle of the front wheels.

[0065] Based on the above, the lateral dynamics model of vehicle i can be comprehensively expressed as:

[0066]

[0067] Generally, lateral control aims to ensure that vehicles in the queue move along the road centerline, meaning the actual driving path matches the reference path, and the error between the two should be close to zero. Therefore, a lateral error model is introduced.

[0068] The lateral position error between the center of gravity of the i-th vehicle and the lane centerline is used The heading error of the i-th vehicle relative to the lane centerline is represented by... Therefore, the lateral error model can be expressed as:

[0069]

[0070] in, Let be the heading angle of vehicle i. Indicates the direction angle of the lane centerline. c represents the desired yaw rate. i It refers to the curvature of the road.

[0071] use Let i represent the lateral state of the i-th vehicle. Indicates lateral control input, t y,i (t) represents the unknown lateral input delay of the actuator. Furthermore, the lateral input delay has an upper bound. The derivative of the lateral input delay also has an upper bound.

[0072] In summary, the lateral model of the vehicle can be expressed as:

[0073] in:

[0074]

[0075] S2. Design a vehicle platoon lateral and longitudinal coordination controller.

[0076] The longitudinal and lateral coordinated controller includes a longitudinal controller designed based on the vehicle's longitudinal model and a lateral controller designed based on the vehicle's lateral model;

[0077] (21) Regarding the longitudinal controller

[0078] Longitudinal controller

[0079] Considering communication time delay t ci,i-1 The communication topology of the lead vehicle and the navigator vehicle. ci,j Let represent the communication delay from vehicle j to vehicle i, and let the communication delay have an upper bound. The derivative of communication delay also has an upper bound. Design the following control law:

[0080] However, due to data latency or loss in vehicle-to-vehicle communication (which can be equivalent to latency), the vehicle platoon may be unstable. To ensure consistency in tracking error, each following vehicle in the platoon should know the state information of the lead vehicle. Therefore, the following distributed observer is designed to estimate the state of the lead vehicle:

[0081]

[0082] Where ε is a constant greater than zero and η i (t) = 0, t ≤ 0. η i-1 (tt ci ) indicates that vehicle i-1 sends observation information η to vehicle i. i The communication delay of (t) is t ci (i.e., η) i-1 (tt ci ) indicates that the communication delay for vehicle i-1 is t. ci,i-1 The channel sends observation information η to vehicle i. i (t)), similarly, x0(tt)ci,0 ) indicates that the navigator vehicle sends observation information η to vehicle i. i The communication delay of (t) is t ci,0 .

[0083] In summary, the longitudinal controller is expressed as follows: Among them, K x,i This indicates the longitudinal control gain.

[0084] The longitudinal control gain K x,i It can be obtained by solving linear matrix inequalities:

[0085]

[0086] Ψ1(1,2)=PM-αM T A T ;

[0087]

[0088] Where P, Q, R, S are the positive definite matrices to be solved and S, M, Y are the matrices to be solved. If the linear inequality has a feasible solution, then K x,i =YM -1 .

[0089] (22) Regarding the lateral controller

[0090] The control objective for the lateral performance of the vehicle fleet is to maintain alignment with the road centerline. The output of the lateral controller is designed as follows: And design a lateral tracker:

[0091]

[0092] in,

[0093] Further design a memoryless H ∞ A state feedback controller is used to ensure that the closed-loop system of the lateral tracker is asymptotically stable and has the following performance indicators:

[0094]

[0095] In summary, the feedback-type lateral controller is obtained as follows: Among them, K y,i This indicates the lateral control gain.

[0096] The lateral control gain K y,i This can be obtained by solving the following matrix inequalities:

[0097]

[0098] Where L > 0, R > 0, W > 0, M and N are the variables to be solved. If the linear matrix inequality has a feasible solution, then K y,i =VL -1 .

[0099] S3. Control the vehicle's lateral and longitudinal movement via the lateral and longitudinal coordination controller.

[0100] (31) The longitudinal controller ensures that the target following vehicle maintains the desired vehicle distance from the lead vehicle and tracks the speed of the lead vehicle;

[0101] The following error when the target vehicle tracks the speed of the lead vehicle is expressed as: Where, d i,j =[(ij)d des 00] T d des This represents the desired distance error. Based on this, the specific control in this step can be considered as controlling the following error between the target vehicle and the lead vehicle to be infinitely close to 0, maintaining the desired vehicle distance d between them. des .

[0102] (32) The target following vehicle is controlled to move along the center line of the road by the lateral controller;

[0103] Specifically, control means that the lateral position error and heading error of each vehicle should be as close to zero as possible, that is, the lateral position error between the center of mass of vehicle i and the center line of the lane. Approaching 0, the heading error of vehicle i relative to the lane centerline Approaching 0.

[0104] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A vehicle platoon lateral and longitudinal coordinated control method with external disturbances, input time delay, and communication delay, characterized in that, Includes the following steps: S1. Establish a vehicle queuing model The vehicle queuing model includes a longitudinal vehicle model that considers longitudinal input delay and communication delay, and a lateral vehicle model that considers lateral input delay. The expression for the longitudinal model of the vehicle is: ;in, They are the first The vehicle's longitudinal position, velocity, and acceleration. Represents the longitudinal dynamic time constant. Indicates longitudinal control input. It is the unknown bounded longitudinal input time lag of the accelerator and brake pedals. And vertical input time delay The derivative of is bounded above, i.e. ; The vehicle's lateral model is constructed based on a two-degree-of-freedom bicycle model, and the expression of the two-degree-of-freedom bicycle model is: in, Indicates the first The vehicle's lateral speed, Indicates the first The yaw rate of the vehicle, Indicates circling moment of inertia of the shaft and These represent the distances from the front and rear axles to the center of mass, respectively. and These represent the lateral forces of the front and rear tires, respectively. The lateral model of the vehicle is expressed as follows: ; ； ； ； in, , Indicates the first The lateral positional error between the vehicle's center of gravity and the lane centerline. Indicates the first The heading error of a vehicle relative to the center line of the lane. Indicates lateral control input. and These represent the lateral stiffness of the front and rear tires, respectively. This represents the lateral input delay of the unknown actuator, and ; S2. Design a horizontal and vertical coordinated controller The longitudinal and lateral coordinated controller includes a longitudinal controller designed based on the vehicle's longitudinal model and a lateral controller designed based on the vehicle's lateral model; S3. Control the vehicle's lateral and longitudinal movement via the aforementioned lateral and longitudinal coordination controller. The longitudinal controller ensures that the target following vehicle maintains the desired vehicle distance from the lead vehicle and tracks the speed of the lead vehicle. The target following vehicle is controlled to move along the center line of the road by the lateral controller.

2. The vehicle platooning lateral and longitudinal coordinated control method with external disturbances, input time delays, and communication delays as described in claim 1, characterized in that: From vehicles To the vehicle The communication delay is expressed as ,and .

3. The vehicle platooning lateral and longitudinal coordinated control method with external disturbances, input time delays, and communication delays as described in claim 2, is characterized in that... choose As the first The longitudinal system state of the vehicle, and the following error expression when the target following vehicle tracks the speed of the lead vehicle are: ;in, , This represents the expected spacing error.

4. The vehicle platooning lateral and longitudinal coordinated control method with external disturbances, input time delays, and communication delays as described in claim 3, is characterized in that, The expression for the longitudinal controller is: ； ； in, Indicates the longitudinal control gain. Indicates vehicle To the vehicle Send observation information with communication delay status. Indicates the navigator vehicle is moving towards the vehicle. Send observation information with communication delay, the communication delay status including communication time lag. , It is a constant greater than zero and .

5. The vehicle platooning lateral and longitudinal coordinated control method according to claim 4, characterized in that, The longitudinal control gain The expression is: ； ; ; ; ; ; ; ; ; ; Among them, positive definite symmetric matrix sum matrix The solution can be found using the Yalmip toolbox in Matlab.

6. The vehicle platooning lateral and longitudinal coordinated control method according to claim 1, characterized in that, The expression for the lateral controller is: ； in, , , , This indicates the lateral control gain.

7. The vehicle platooning lateral and longitudinal coordinated control method according to claim 6, characterized in that, The lateral control gain The expression is: ； ； ； Among them, matrix The solution can be found using the Yalmip toolbox in Matlab.

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