RU2782521C1 - Method and system for planning of transverse trajectory of automatic change of car lane, car, and data carrier - Google Patents

Abstract

FIELD: car industry.

SUBSTANCE: invention relates to the field of technology of automatic control of a motor vehicle and, in particular, to a method and a system for planning of a transverse trajectory of automatic change of a car lane, to a car, and a data carrier. The method includes stages of information processing, calculation of parameters of automatic change of a lane, planning of a fifth order curve for automatic change of the lane, formation of a transverse control command for automatic change of the lane, and calculation of a solution on completion of automatic change of the lane. The system for planning of a transverse trajectory of automatic change of a car lane contains memory and a controller, while memory stores a machine-readable program, and the controller calls the machine-readable program. The motor vehicle is made with the possibility of use of the system for planning of a transverse trajectory of automatic change of a lane. The data carrier is also described, on which the machine-readable program is stored, in calling which the controller can perform stages of the method for planning of a transverse trajectory.

EFFECT: increase in computing efficiency, when planning a trajectory.

10 cl, 1 dwg

Description

Technical field

The present invention relates to the field of technology for automatic control of a motor vehicle (hereinafter referred to as a car), and, in particular, to a method and system for planning a transverse trajectory for an automatic lane change of a car, to a car and an information carrier.

State of the art

With the development of artificial intelligence technologies, multi-sensor integration technologies, and control and decision-making technologies, the demand for automatic vehicle control is growing. Depending on the application scenario, technical capabilities, etc. autonomous vehicles, there are five levels from L1 to L5, where L2 is advanced driving assistance, L3 is conditional automatic driving, L4 is fully automatic driving in confined spaces, and L5 is fully automatic driving.

The industry is currently focused on mass production of L2 and L3 level systems. At these levels, the technology is primarily focused on enabling limited automated driving in urban or high-speed highway scenarios, including core features such as lane centering, adaptive cruise control, and automatic lane change.

The actual method for planning the lateral path of an automatic lane change of a vehicle is mainly divided into two types: a method based on a high-precision map and a method based on positioning a lane line. The path planning method based on the high-precision map is characterized by high accuracy and strong anti-interference ability, but the system is complicated and expensive. At present, the method is not applicable for mass implementation.

As for the above technical problem, no effective solution has yet been proposed for it.

The essence of the invention

In at least some embodiments, the present invention provides a method and system for planning an automatic lane change transverse trajectory of a vehicle, a vehicle, and a storage medium that can improve computational efficiency in constructing such a trajectory.

In an embodiment of the present invention, a method for planning a transverse trajectory of an automatic lane change of a vehicle is provided, including the following steps:

(1) information processing:

receiving the automatic lane change instruction data output by the decision system and determining whether to start the automatic lane change, wherein in the case of determining the start of the automatic lane change, the lane center line data of the host vehicle (following vehicle) is received. means) , the center line of the target lane and the speed V of the host vehicle, output by the sensor system in real time, and in case of not detecting the start of an automatic lane change, the process is completed;

(2) calculation of automatic lane change parameters:

at the start time of the automatic lane change, the calculation of the relative lateral distance TargetA0 between the center line of the target lane and the center line of the lane of the host vehicle, and the calculation of the time parameter T used to construct the lateral trajectory of the automatic lane change, in combination with a calibration variable indicating the speed of the lane change process;

(3) Fifth order curve construction for automatic lane change:

at each automatic lane change time, the calculation of the parameters N ₀ , N ₁ , N ₂ , N ₃ , N ₄ , N ₅ of the fifth order curve equation is performed in accordance with the relative lateral distance TargetA0 between the axial target lane and the axial lane of the host car, and also the time parameter T, used for planning the lateral deviation during automatic lane change; and, in addition, the calculation of the required lateral distance S _target , the required lateral speed V _target and the required lateral acceleration A _target at time t;

(4) generation of lateral control instruction for automatic lane change:

calculation of parameters A0_lc, A1_lc, A2_lc, A3_lc equations of the cubic curve of the lane change trajectory at time t according to the required lateral distance S_target, required transverse speed V_targetand required lateral acceleration A_target and in combination with the parameters A0_lk, A1_lk, A2_lk, A3_lk cubic curve equations lane center line of the host vehicle, calculating the parameters A0, A1, A2, A3 of the cube curve equation for lateral control, and outputting the parameters A0, A1, A2, A3 of the cube curve equation of the path to the lateral control controller to perform lateral control in automatic lane change movement;

(5) automatic lane change completion calculation:

when the following two conditions are met simultaneously, the automatic lane change is considered to be completed:

(a) the time period used for the automatic lane change is greater than the automatic lane change trajectory construction time parameter T;

(b) the parameter A0 of the cubic trajectory equation used for lateral control is less than the limit value A0 _Comp , and the time period A0 < A0 _Comp is less than the limit value T _Comp ;

after the completion of the automatic lane change, the fifth-order curve calculation of the planning procedure and the automatic lane change lateral control instruction are stopped, if the automatic lane change is not completed, the process returns to step (3).

In the embodiment in step (1), the lane center line of the host vehicle is expressed by fitting (point-by-point) a cubic curve to obtain y _lk =A0 _lk +A1 _lk x+A2 _lk x ² +A3 _lk x ³ , where y _lk is the lateral distance, x is the longitudinal distance, and A0 _lk , A1 _lk , A2 _lk and A3 _lk are the parameters of the cubic curve equation of the lane center line of the host vehicle;

axial target band is expressed through a cubic curve fit to give y _lt =A0 _lt +A1 _lt x+A2 _lt x ² +A3 _lt x ³ , where y _lt is the lateral distance, x is the longitudinal distance, and A0 _lt , A1 _lt , A2 _lt and A3 _lt - parameters of the equation of the cubic curve of the center line of the vehicle's target lane.

In the embodiment in step (2), the formula for calculating the time parameter T for planning the automatic lane change trajectory is as follows:

;

;

formula for calculating the relative lateral distance TargetA0 between the center line of the target lane and the center line of the host vehicle lane:

TargetA0 = A0 _lt - A0 _lk .

In the embodiment, in step (3), a method for calculating the parameters N ₀ , N ₁ , N ₂ , N ₃ , N ₄ , N ₅ of the fifth order curve equation:

;matrix construction

;

;matrix construction

;

where V _i is the lateral speed at the beginning of the automatic lane change, a _j is the lateral acceleration at the beginning of the automatic lane change, V _f is the lateral speed at the end of the automatic lane change and a _f is the lateral acceleration at the end of the automatic lane change;

solution of the matrix equation:

. to obtain c(1), c(2), c(3), and then to obtain the fifth order curve equation parameter

.

In the embodiment in step (3)

required lateral distance S _target = N ₀ + N ₁ t + N ₂ t ² + N ₃ t ³ + N ₄ t ⁴ + N ₅ t ⁵ ;

required lateral speed V _target = N ₁ + 2N ₂ t + 3N ₃ t ² + 4N ₄ t ³ + 5N ₅ t ⁴ ;

and the required lateral acceleration A _target = 2N ₂ +6N ₃ t+12N ₄ t ² +20N ₅ t ³ .

In the embodiment in step (4), A0 _lc = S _target ; A1 _lc = V _target /V; A2 _lc = A _target /(2*V ² ); A3 _lc = 0.

In the embodiment in step (4), [A0, A1, A2, A3] = [ A0_lc+A0_lk, A1_lc+A1_lk, A2_lc+A2_lk, A3_lc+A3_lk].

In another embodiment, the present invention also provides an auto lane change lateral trajectory planning system including a memory and a controller, wherein the memory stores a computer readable computer program and the controller calls the computer readable computer program to perform the steps of the auto lane change lateral trajectory planning method of the present invention. invention.

In another embodiment of the present invention, there is further provided a vehicle in which an automatic lane change lateral trajectory planning system according to the present invention is applied.

In another embodiment of the present invention, a storage medium is further provided on which a computer readable program is stored, wherein the computer readable program, when called by the controller, can perform the steps of the automatic vehicle lane change trajectory planning method according to the present invention.

At least some embodiments of the present invention have the following advantages.

(1) Adopted the currently dominant vehicular lane direction positioning scheme to realize automatic lane change trajectory planning, which is proven and reliable.

(2) This scheme is compatible with the current lane centering function, which reduces costs and enables mass production.

(3) The proposed trajectory planning method has a high computational efficiency and meets the level of requirements for on-board computing.

(4) The camera is used to obtain lane information without applying high precision map positioning, so it has high noise immunity.

Brief description of the drawings

The drawing is a flowchart of a method for planning an automatic lane change of a vehicle according to an embodiment of the present invention.

Detailed description

Hereinafter, the present invention is described in more detail with reference to the accompanying drawings.

As an embodiment of the present invention, the hardware involved in implementing the automatic lane change vehicle transverse trajectory planning method may include, but is not limited to: a sensor system configured to detect and output lane center line data of the driven (host) vehicle, target lane centerline and host car speed in real time; an automatic lane change decision system configured to output automatic lane change instruction information; an automatic lane change lateral trajectory planning system configured to precalculate a fifth-order lateral curve equation for automatic lane change in real time, calculate a required lateral distance, a required speed, and a required acceleration, and calculate parameters of a cubic curve configured for lateral control; and an automatic lane change lateral control controller configured to receive the cubic curve parameters calculated by the automatic lane change lateral trajectory planning system and complete corresponding lateral control actions.

As shown in FIG. 1, in this embodiment, a method for planning a lateral trajectory of an automatic lane change of a vehicle is presented, including the steps described below.

(1) Information processing.

11. Obtaining automatic lane change instruction data output by the decision system and determining whether to start automatic lane change; in the case of determining the start of an automatic lane change, proceed to step 12; if the start of an automatic lane change is not detected, the process is terminated.

12. Obtaining information output by the sensor system in real time, including data: the center line of the lane of the driven vehicle, expressed by the approximation of the cubic curve to obtain y _lk =A0 _lk +A1 _lk x+A2 _lk x ² +A3 _lk x ³ , where y _lk - transverse distance, x - longitudinal distance; the center line of the target strip, expressed by a cubic curve fit to give y _lt =A0 _lt +A1 _lt x+A2 _lt x ² +A3 _lt x ³ , where y _lt is the lateral distance, x is the longitudinal distance; and speed V of the host car.

(2) Calculation of automatic lane change parameters.

, где rate (скорость) - калибровочная переменная, определяющая скорость процесса смены полосы движения, причём вычисление выполняется один раз в момент начала каждого процесса смены полосы движения; при этом в ходе фактического процесса смены полосы движения величина временного параметра T в среднем составляет между 6 и 8 секундами.12. Calculation of the time parameter T, spent on planning the transverse trajectory of an automatic lane change, according to the formula:

, where rate (speed) is a calibration variable that determines the speed of the lane change process, and the calculation is performed once at the start of each lane change process; however, during the actual lane change process, the value of the time parameter T averages between 6 and 8 seconds.

22. Calculating the relative lateral distance TargetA0 = A0 _lt - A0 _lk between the target lane center line and the trailing vehicle lane center line according to the parameters of the target lane center line and the trailing vehicle lane center line obtained in step 12.

(3) Fifth order curve construction for automatic lane change.

31. Calculation of the fifth order curve equation y = N ₀ +N ₁ t+N ₂ t ² +N ₃ t ³ +N ₄ t ⁴ +N ₅ t ⁵ for planning the transverse lane change trajectory at time t according to TargetA0 obtained at step 22, where N ₀ , N ₁ , N ₂ , N ₃ , N ₄ , N ₅ are the parameters of the fifth order curve equation, and y is the transverse distance; calculation of the parameters N ₀ , N ₁ , N ₂ , N ₃ , N ₄ , N ₅ of the fifth-order curve equation is performed by

,matrix construction

,

where T is the time parameter obtained by the calculation in step 2;

,matrix construction

,

where TargetA0 is the lateral distance calculated in step 2, V _i , a _j are respectively the lateral speed and lateral acceleration (usually taken as 0) at the beginning of the automatic lane change, and V _f , a _f are respectively the lateral speed and lateral acceleration acceleration (usually taken as 0) at the end of an automatic lane change;

solutions of the matrix equation:

уравнения кривой пятого порядка.getting c(1), c(2), c(3) and then getting the parameter

curve equations of the fifth order.

32. Calculation of the required lateral distance

S _target = N ₀ +N ₁ t+N ₂ t ² +N ₃ t ³ +N ₄ t ⁴ +N ₅ t ⁵ ;

required lateral speed V _target = N ₁ +2N ₂ t+3N ₃ t ² +4N ₄ t ³ +5N ₅ t ⁴

and the required lateral acceleration A _target = 2N ₂ +6N ₃ t+12N ₄ t ² +20N ₅ t ³ at time t.

(4) Generation of lateral control instruction for automatic lane change.

41. Calculation of the parameters A0 _lc , A1 _lc , A2 _lc , A3 _lc of the equation of the cubic curve of the lane change trajectory at time t in accordance with the required lateral distance S _target , the required lateral speed V _target and the required lateral acceleration A _target , calculated in step 33 and the speed V of the host vehicle obtained in step 11, while A0 _lc = S _target ; A1 _lc = V _target /V; A2 _lc = A _target /(2*V ² ); A3 _lc = 0.

42. Obtaining the parameters of the equation of the cubic curve of the trajectory [A0, A1, A2, A3] = [A0 _lc + A0 _lk , A1 _lc + A1 _lk , A2 _lc + A2 _lk , A3 _lc + A3 _lk ] for lateral control according to the parameters A0 _lk , A1 _lk , A2 _lk and A3 _lk equations of the cubic curve of the lane center line of the trailing vehicle, and outputting information to the lateral control controller for performing lateral control during automatic lane change.

(5) Completion calculation for automatic lane change.

Determining whether the automatic lane change is completed according to the following conditions:

(a) the period of time spent in the automatic lane change exceeds the automatic lane change lateral trajectory planning time parameter T;

(b) determining, according to the parameter A0 of the trajectory cubic curve equation for lateral control obtained in step 4, whether this parameter is less than the limit value A0 _Comp , and the time period A0 < A0 _Comp is less than the limit value T _Comp .

If condition (a) and condition (b) are satisfied at the same time, it is determined that the automatic lane change is completed, and the calculation for fifth-order curve planning and the generation of automatic lane change lateral control commands are stopped. If at least one of conditions (a) or (b) is not satisfied, the process returns to step 22.

In another embodiment of the present invention, an auto lane change lateral trajectory planning system is provided, comprising a memory and a controller, wherein a computer readable computer program is stored in the memory, and the controller calls the computer readable computer program to perform the steps of the automatic lane change lateral trajectory planning method described above. car.

In another embodiment of the present invention, a vehicle is further provided in which the above-mentioned automatic lane change vehicle transverse trajectory planning system is applied.

In another embodiment of the present invention, a storage medium is further provided on which a computer-readable computer program is stored, which, when called by the controller, is capable of performing the steps of the automatic lane change trajectory planning method of the aforementioned vehicle.

Based on several embodiments presented in this application, it should be understood that the disclosed technical content can be implemented in other ways. The embodiments of the device described above are given only as examples. For example, the separation of elements may be a separation of logical functions, and in practical implementation, other methods of separation can be applied. So, many elements or components can be combined or integrated into another system, or some functions can be neglected or not performed. In addition, the interconnections or direct links or communication connections that are displayed or discussed can be implemented via various interfaces. Indirect connections or communication connections between elements or components may be implemented in electrical or other forms.

Items described as separate components may or may not be physically separated, and individual components displayed as items may or may not be physical items, mounted in a single position, or distributed across multiple items. Some or all of the elements may be selected according to actual requirements in order to achieve the objectives of the technical solutions of the embodiments.

In addition, functional elements in embodiments of the present invention may be integrated into a single processing node, or each of the elements may exist separately physically, or at least two elements may be integrated into one element. An integrated element may be implemented as a hardware element, or it may be implemented as a software functional element.

When an integrated element is implemented as a software functional element and sold or used as a standalone product, such integrated element may be stored on a computer-readable storage medium. Based on this understanding, the technical solutions of the present invention essentially or the part contributing to the prior art, or all or part of the technical solutions can be implemented in the form of a software product. The computer program product is stored on a storage medium. The software product includes several instructions for instructing a computing device (which may be a personal computer, a server, a network device, and the like) to perform all or part of the steps of the methods described in the embodiments of the present invention. The aforementioned storage medium includes any medium that can store program codes such as a USB flash drive, Read Only Memory (ROM), Random Access Memory (RAM), mobile hard disk, magnetic disk or optical disk.

The above contents are exemplary embodiments of the present invention. It should be noted that further improvements and modifications may be made by one skilled in the art without departing from the principle of the present invention, and these improvements and modifications should also fall within the protection scope of the present invention.

Claims (39)

1. A method for planning a transverse trajectory for an automatic lane change of a car, including the following steps: (1) information processing: receiving the automatic lane change instruction data output by the decision system, and determining whether to start the automatic lane change, wherein in case of determining the start of the automatic lane change, receiving the lane center line of the host vehicle, the center line the target lane and the speed V of the host car output by the sensor system in real time, and if the start of automatic lane change is not detected, the process is completed; (2) calculation of automatic lane change parameters: at the start time of the automatic lane change, the calculation of the relative lateral distance TargetA0 between the center line of the target lane and the center line of the lane of the host vehicle, and the calculation of the time parameter T used to construct the lateral trajectory of the automatic lane change, in combination with a calibration variable indicating the speed of the lane change process; (3) Fifth order curve construction for automatic lane change: at each time of the automatic lane change, the calculation of the parameters N ₀ , N ₁ , N ₂ , N ₃ , N ₄ , N ₅ of the fifth-order curve equation is performed in accordance with the relative lateral distance TargetA0 between the axial target lane and the axial lane of the host car, and also the time parameter T used for planning the lateral deflection in automatic lane change, and the calculation of the required lateral distance S _target , the required lateral speed V _target and the required lateral acceleration A _target at time t; (4) generation of lateral control instruction for automatic lane change: calculation of the parameters A0 _lc , A1 _lc , A2 _lc , A3 _lc of the cubic curve equation of the lane change trajectory at time t according to the required lateral distance S _target , the required lateral speed V _target and the required lateral acceleration A _target and in combination with the parameters A0 _lk , A1 _lk , A2 _lk , A3 _lk equations of the cubic curve of the lane center line of the host vehicle, calculation of parameters A0, A1, A2, A3 of the equation of the cubic curve of the trajectory for lateral control, and output of the parameters A0, A1, A2, A3 of the equation of the cubic curve trajectory to the lateral control controller to perform lateral control during automatic lane change; (5) automatic lane change completion calculation: if the following two conditions are met simultaneously, the automatic lane change is considered to be completed: (a) the time period used for the automatic lane change is greater than the time parameter T for constructing the automatic lane change lateral trajectory; (b) the parameter A0 of the cubic trajectory equation used for lateral control is less than the limit value A0 _Comp , and the time period A0 < A0 _Comp is less than the limit value T _Comp ; after completion of the automatic lane change, the fifth-order curve calculation of the scheduling procedure and generation of the automatic lane change lateral control instruction are stopped; if the automatic lane change is not completed, the process returns to step (3). 2. The method according to p. 1, characterized in that that in step (1), the lane center line of the host vehicle is expressed by a cubic curve fit to obtain y _lk = A0 _lk + A1 _lk x + A2 _lk x ² + A3 _lk x ³ , where y _lk is the lateral distance, x is the longitudinal distance, and A0 _lk , A1 _lk , A2 _lk and A3 _lk are the parameters of the cubic curve equation of the lane center line of the host vehicle; axial target lane is expressed by fitting a cubic curve to obtain y _lt = A0 _lt + A1 _lt x + A2 _lt x ² + A3 _lt x ³ , where y _lt is the lateral distance, x is the longitudinal distance, and A0 _lt , A1 _lt , A2 _lt and A3 _lt are the parameters of the cubic curve equation of the center line of the vehicle's target lane. 3. The method according to p. 2, characterized in that what at step (2), the formula for calculating the time parameter T for planning the transverse trajectory of an automatic lane change of a car has the following form:

; formula for calculating the relative lateral distance TargetA0 between the center line of the target lane and the center line of the host vehicle lane: TargetA0 = A_0lt - A_0lk. 4. The method according to claim 3, characterized in that at stage (3) the calculation of the parameters N ₀ , N ₁ , N ₂ , N ₃ , N ₄ , N ₅ of the fifth-order curve equation is performed by: matrix construction

; matrix construction

; where V _i is the lateral speed at the beginning of the automatic lane change, a _j is the lateral acceleration at the beginning of the automatic lane change, V _f is the lateral speed component at the end of the automatic lane change, and a _f is the lateral acceleration at the end of the automatic lane change; solutions of the matrix equation:

getting c(1), c(2), c(3) and then getting the parameter

curve equations of the fifth order. 5. The method according to p. 4, characterized in that in step (3) required lateral distance S _target = N ₀ +N ₁ t+N ₂ t ² +N ₃ t ³ +N ₄ t ⁴ +N ₅ t ⁵ ; required lateral speed V _target = N ₁ +2N ₂ t+3N ₃ t ² +4N ₄ t ³ +5N ₅ t ⁴ ; and required lateral acceleration A _target = 2N ₂ +6N ₃ t+12N ₄ t ² +20N ₅ t ³ . 6. The method according to p. 5, characterized in that in step (4) A0 _lc = S _target ; A1 _lc = V _target /V; A2 _lc = A _target /(2*V ² ); A3 _lc = 0. 7. The method according to paragraphs. 3-6, characterized in that at step (4) [A0, A1, A2, A3] = [A0_lc+A0_lk, A1_lc+A1_lk, A2_lc+A2_lk, A3_lc+A3_lk]. 8. An auto lane change lateral trajectory planning system, comprising a memory and a controller, wherein the memory stores a computer readable program, and the controller calls the computer readable program to perform the steps of the auto lane change lateral trajectory planning method as claimed in any one of claims. 1-7. 9. A motor vehicle configured to use the automatic lane change transverse trajectory planning system according to claim 8. 10. A storage medium on which a machine-readable computer program is stored, when called by the controller, the steps of the method for planning the transverse trajectory of an automatic lane change of a vehicle according to any one of paragraphs can be performed. 1-7.

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