Path planning method and device, traction trailer and computer program product

Abstract

The invention is suitable for the technical field of path planning, and provides a path planning method and device, a traction trailer and a computer program product. The path planning method is applied to a traction trailer. The path planning method comprises the steps that the current position of a tractor is obtained, a starting point is determined based on the current position, sampling is carried out within a preset distance range from the starting point according to a preset distance step length and a transverse offset step length, sampling points are obtained, polynomial fitting is carried out based on the starting point and the sampling points, and an initial sampling path is obtained; determining the trailer position of the trailer when the tractor is located at each sampling point; based on the position of the trailer, the obstacle condition of the area where the traction trailer is located is determined, and based on the obstacle condition, a target path where the traction trailer does not collide is determined in the initial sampling path. According to the embodiment of the invention, the trailer can be prevented from colliding with an obstacle, and the driving safety is improved.

Description

Technical Field

[0001] The present application belongs to the field of path planning technology, and in particular relates to a path planning method, device, tractor trailer, and computer program product. Background Art

[0002] Current path planning is mostly designed for autonomous vehicles. However, in the case of tractor-trailer motion planning, since the trailer is unpowered, its motion is affected by the movements of both the tractor and the preceding trailer. Therefore, path planning for a tractor-trailer is a complex problem. Using conventional path planning methods directly can easily lead to collisions between the towed vehicle and obstacles, seriously impacting the safety of the tractor-trailer. Summary of the Invention

[0003] The embodiments of the present application provide a path planning method, device, tractor trailer, and computer program product, which can prevent the tractor trailer from colliding with obstacles and improve driving safety.

[0004] According to a first aspect of an embodiment of the present application, a path planning method is provided, which is applied to a towing trailer, wherein the towing trailer includes a tractor and a trailer, and when the tractor moves, the trailer is driven to move by a connecting member; the path planning method includes: obtaining the current position of the tractor; determining a starting point based on the current position; sampling within a preset distance range starting from the starting point according to a preset distance step and a lateral offset step to obtain sampling points; performing polynomial fitting based on the starting point and the sampling points to obtain an initial sampling path; determining the trailer position of the trailer when the tractor is located at each of the sampling points; determining the obstacle situation in the area where the towing trailer is located based on the trailer position, and determining a target path for the towing trailer without collision in the initial sampling path based on the obstacle situation.

[0005] In some embodiments of the first aspect, determining an obstacle condition in the area where the towing trailer is located based on the trailer position, and determining a target path in which the towing trailer does not collide within the initial sampling path based on the obstacle condition includes: determining, based on the sampling points, the tractor size of the tractor, the trailer position, and the trailer size, the area where the towing trailer is located when the tractor is located at each sampling point; when the number of obstacle point clouds in the area where the towing trailer is located is less than or equal to a number threshold, the towing trailer does not collide when the tractor is located at the corresponding sampling point; and if the tractor does not collide when the tractor is located at each sampling point on the initial sampling path, then using the initial sampling path as the target path.

[0006] In some embodiments of the first aspect, if there are multiple initial sampling paths without collision, determining a target path for the tractor-trailer without collision among the initial sampling paths includes: taking the initial sampling paths without collision as alternative paths, determining a path score for each of the alternative paths, the path score being associated with the path length of the alternative path and / or the lateral offset of each sampling point passed by the alternative path; and determining the target path among the multiple alternative paths based on the path scores.

[0007] In some embodiments of the first aspect, determining the path score of each alternative path includes: determining an offset difference between each sampling point and a previous sampling point based on the lateral offset of each sampling point passed by the alternative path; and determining the path score of each alternative path based on the path length of the alternative path, the lateral offset of each sampling point passed by the alternative path, and the offset difference.

[0008] In some embodiments of the first aspect, determining the trailer position of the trailer when the tractor is at each sampling point includes: determining a trailer angle of the trailer when the tractor is at the corresponding sampling point based on a tractor speed of the tractor when the tractor is at each sampling point; and determining the trailer position of the trailer when the tractor is at each sampling point based on the trailer angle of the trailer when the tractor is at each sampling point and the position of the sampling point.

[0009] In some embodiments of the first aspect, for a first trailer directly connected to the tractor, determining the trailer angle of the trailer when the tractor is located at the corresponding sampling point based on the tractor speed when the tractor is located at each sampling point includes: determining a heading angle difference between the tractor and the first trailer when the tractor is located at each sampling point; and for each sampling point, dividing the product of the tractor speed when the tractor is located at the sampling point, the sine value of the heading angle difference, and a sampling time interval by a first distance between the connector and the trailer center of the first trailer to obtain the trailer angle of the first trailer when the tractor is located at the sampling point.

[0010] In some embodiments of the first aspect, for a second trailer indirectly connected to the tractor, determining the trailer angle of the tractor when the tractor is at the corresponding sampling point based on the tractor speed when the tractor is at each sampling point includes determining the trailer angle of the second trailer when the tractor is at the corresponding sampling point based on the tractor speed when the tractor is at each sampling point and the trailer angle of the previous trailer.

[0011] According to a second aspect of an embodiment of the present application, a path planning device is provided, which is configured for a towing trailer, wherein the towing trailer includes a tractor and a trailer, and when the tractor moves, the trailer is driven to move by a connecting member; the path planning device includes: a tractor position acquisition unit for acquiring the current position of the tractor; a starting point determination unit for determining a starting point based on the current position; a sampling point determination unit for sampling within a preset distance range starting from the starting point according to a preset distance step and a lateral offset step to obtain sampling points; a path sampling unit for performing polynomial fitting based on the starting point and the sampling points to obtain an initial sampling path; a trailer position determination unit for determining the trailer position of the trailer when the tractor is located at each of the sampling points; and a collision detection unit for determining an obstacle condition in the area where the towing trailer is located based on the trailer position, and based on the obstacle condition, determining a target path for the towing trailer in the initial sampling path in which no collision occurs.

[0012] A third aspect of an embodiment of the present application provides a tractor-trailer, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the tractor-trailer comprises a tractor and a trailer, and when the tractor moves, the trailer is driven to move by a connecting member; when the processor executes the computer program, the steps of the above-mentioned path planning method are implemented.

[0013] A fourth aspect of an embodiment of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the above-mentioned path planning method are implemented.

[0014] A fifth aspect of the embodiments of the present application provides a computer program product, which enables the above-mentioned path planning method to be executed when the computer program is run.

[0015] In an embodiment of the present application, by acquiring the current position of the tractor, a starting point is determined based on the current position, and sampling is performed within a preset distance range starting from the starting point according to a preset distance step and a lateral offset step to obtain sampling points. Polynomial fitting is performed based on the starting point and the sampling points to obtain an initial sampling path, and the trailer position of the towing vehicle when the tractor is located at each sampling point on the initial sampling path is determined. Based on the trailer position, the obstacle situation in the area where the towing trailer is located is determined. Based on the obstacle situation, a target path in which the towing trailer does not collide is determined in the initial sampling path, which can avoid collisions between the towing vehicle and obstacles and improve driving safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0017] Figure 1 This is a schematic diagram of an implementation flow of a path planning method provided in an embodiment of the present application;

[0018] Figure 2 is a schematic diagram of a physical model of a tractor trailer provided in an embodiment of the present application;

[0019] Figure 3 This is a schematic diagram of a specific implementation process for determining a target path provided by an embodiment of the present application;

[0020] Figure 4 This is a schematic structural diagram of a path planning device provided in an embodiment of the present application;

[0021] Figure 5 It is a structural schematic diagram of a tractor trailer provided in an embodiment of the present application. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of this application more clear, the present application is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without making any creative work are protected by this application.

[0023] Current path planning is mostly designed for autonomous vehicles. However, in the case of tractor-trailer motion planning, since the trailer is unpowered, its motion is affected by the movements of both the tractor and the preceding trailer. Therefore, path planning for a tractor-trailer is a complex problem. Using conventional path planning methods directly can easily lead to collisions between the towed vehicle and obstacles, seriously impacting the safety of the tractor-trailer.

[0024] In view of this, the present application proposes a path planning method that can avoid collisions between trailers and obstacles and improve driving safety.

[0025] In order to illustrate the technical solution of the present application, specific embodiments are provided below.

[0026] Figure 1A schematic diagram of the implementation flow of a path planning method provided in an embodiment of the present application is shown, which can be applied to a towing trailer.

[0027] In the embodiment of the present application, the tractor trailer includes a tractor and a trailer. When the tractor moves, the trailer is driven to move by the connecting member. The number of the trailer can be one or more. Figure 2 When there are multiple trailers, each trailer is connected in sequence, that is, the first trailer is connected to the tractor through a connector, the second trailer is connected to the first trailer through a connector, and so on, the Nth (N>1) trailer is connected to the N-1th trailer through a connector.

[0028] The connecting member may be a hook, a buckle or other existing connecting member, and this application does not limit this. The tractor may be a four-wheeled vehicle structure, and each trailer may be a two-wheeled vehicle structure, but this application does not exclude the situation where the tractor and trailer use other structures.

[0029] Specifically, the above-mentioned path planning method may include the following steps S101 to S106.

[0030] Step S101, obtaining the current position of the tractor.

[0031] The current position represents the position of the tractor at the current moment. The current position can be obtained by a positioning module on the tractor, or can be calculated based on the position and motion parameters of the tractor at the previous moment, which is not limited in this application.

[0032] Step S102: Determine a starting point based on the current position.

[0033] The starting point is the location where the sampling path begins, representing the location that the tractor first reaches when traveling along the sampling path. Specifically, the starting point can be the current location or any location around the current location, which is not limited in this application.

[0034] Step S103 : within the preset distance range, sampling is performed starting from the starting point according to the preset distance step and lateral offset step to obtain sampling points.

[0035] Among them, the preset distance range is the maximum coverage range of the sampling path. The preset distance step and the lateral offset step characterize the step size of the tractor's offset in two mutually perpendicular directions. Specifically, in the SL coordinate system (i.e., Frenet coordinate system), the horizontal coordinate direction represents the direction of the road centerline (longitudinal), and the horizontal coordinate represents the length / distance of the path. The vertical coordinate direction represents the direction perpendicular to the road centerline (lateral), and the vertical coordinate represents the lateral offset L of the path. The preset distance range, preset distance step and lateral offset step can be set according to actual conditions. The sampling point coordinates can be expressed as (s, s′, s″, l, l′, l″), where s is the distance coordinate of the sampling point, and s′ and s″ are the speed and acceleration of the distance. Similarly, l represents the lateral offset coordinate of the sampling point, and l′ and l″ are the speed (i.e., the lateral offset difference) and acceleration of the lateral offset.

[0036] For example, 10 meters can be selected as the preset distance range, and sampling can be performed with a preset distance step of 1 meter in the longitudinal direction, and sampling can be performed with a lateral offset step of 0, ±1 / 3 lane width, and ±2 / 3 lane width in the lateral direction to obtain 10*5 groups of sampling points.

[0037] Step S104: performing polynomial fitting based on the starting point and the sampling points to obtain an initial sampling path.

[0038] The initial sampling path represents the path obtained by sampling the path starting from the current location. The initial sampling path is obtained by fitting a polynomial using the coordinates of the sampling points with the current location as the starting point. The number of initial sampling paths can be one or more. For example, for the aforementioned 10*5 set of sampling points, a quintic polynomial fitting of the initial and end points can yield 10*5 preliminary sampling paths.

[0039] In an embodiment of the present application, the initial sampling path may include one or more sampling points, each sampling point representing a path point that the tractor will pass through.

[0040] Step S105 , determining the trailer position of the towing vehicle when the tractor is located at each sampling point.

[0041] In an embodiment of the present application, since the relative positional relationship between the tractor and the trailer can be known in advance, when the tractor needs to pass through the sampling points, the trailer position of the trailer when the tractor is located at each sampling point can be determined based on the position of the sampling points.

[0042] Step S106 : Based on the position of the trailer, the obstacle situation in the area where the towing trailer is located is determined, and based on the obstacle situation, a target path in which the towing trailer does not collide is determined in the initial sampling path.

[0043] In the embodiments of the present application, based on the trailer's location, the area within which the tractor and trailer are located can be determined. The obstacles within the area are analyzed to determine whether the tractor and trailer have collided with any obstacles. Initial sampling paths in which the tractor and trailer have collided are then filtered out, and initial sampling paths in which the tractor and trailer have not collided are used as target paths. The target paths can be used for navigation and movement of the tractor and trailer.

[0044] In an embodiment of the present application, by acquiring the current position of the tractor, a starting point is determined based on the current position, and sampling is performed within a preset distance range starting from the starting point according to a preset distance step and a lateral offset step to obtain sampling points. Polynomial fitting is performed based on the starting point and the sampling points to obtain an initial sampling path, and the trailer position of the towing vehicle when the tractor is located at each sampling point on the initial sampling path is determined. Based on the trailer position, the obstacle situation in the area where the towing trailer is located is determined. Based on the obstacle situation, a target path in which the towing trailer does not collide is determined in the initial sampling path, which can avoid collisions between the towing vehicle and obstacles and improve driving safety.

[0045] For details, please refer to Figure 2 , Figure 2 The physical model of a tractor trailer is shown. In this physical model, it is assumed that the wheelbase of the front and rear wheels of the tractor is L W0 , the distance from the rear axle center to the connecting part of the tractor is L H0 , the first distance between the connecting piece and the wheel center of the first trailer is L W1 The distance between the wheel center of the first trailer and the hook between the first trailer and the second trailer is L H1 , and so on, the distance between the center of the n-1th trailer and the hook of the nth trailer and the center of the wheel of the nth trailer is L Wn , the distance between the wheel center of the nth trailer and the hook of the nth trailer is L Hn .

[0046] In some embodiments of the present application, obtaining the current position of the tractor may include: determining the current position of the tractor based on the posture of the tractor at a previous moment, the tractor speed of the tractor at the current moment, and the steering gear angle at the current moment.

[0047] Specifically, for time t, the position at the previous time t-dt can be expressed as the coordinates of the rear axle center P0 (x0(t-dt), y0(t-dt)) and the heading angle θ0(t-dt). The motion model based on the Ackerman model can determine the coordinates of the rear axle center P0 (x0(t-dt), y0(t-dt)) and the heading angle θ0(t-dt) at time t based on the coordinates of the rear axle center P0 at the previous time (x0(t-dt), y0(t-dt)) and the heading angle θ0(t-dt), as well as the tractor speed v0 and the steering gear deflection angle φ of the tractor at time t:

[0048] x0(t)=x0(t-dt)+v0*cos(θ0(t-dt))*dt,

[0049] y0(t)=y0(t-dt)+v0*sin(θ0(t-dt))*dt,

[0050]

[0051] Taking the current position as the starting point, the initial sampling path can be obtained by fitting the polynomials in combination with the coordinates of the sampling points. Figure 2 The physical model shown performs the calculation of the trailer position.

[0052] Specifically, assume that the wheels of a trailer and the wheels of the vehicle in front of it form a new Ackerman model structure. Due to the traction of the front vehicle on the rear vehicle, the tractor speed v0 at time t is transmitted to the rear vehicle, that is, the speed of the rear vehicle is v1. The trailer angle of the first trailer at time t can be obtained. The trailer angle of the first trailer is specifically expressed as formula (1):

[0053]

[0054] Where θ0(t-dt) is the heading angle of the rear axle center P0 at time t-dt, θ1(t-dt) is the heading angle of the trailer center at time t-dt, and dt is the sampling time interval.

[0055] Based on the traction and speed transfer relationship between the trailers, the trailer angle of any trailer following the first trailer at time t can be obtained. The trailer angle of any trailer can be expressed as formula (2):

[0056]

[0057] After obtaining the trailer angle of any trailer, the trailer position of the nth trailer (x n (t),y n (t)). x n(t),y n (t) can be expressed by the following formula (3):

[0058]

[0059] Based on the above principles, determining the trailer position of the towed vehicle when the tractor is at each sampling point may include: determining the trailer angle of the towed vehicle when the tractor is at the corresponding sampling point based on the tractor speed when the tractor is at each sampling point; and determining the trailer position of the towed vehicle when the tractor is at each sampling point based on the trailer angle of the towed vehicle when the tractor is at each sampling point and the position of the sampling point.

[0060] Specifically, by converting the Frenet coordinate system to the Cartesian XY coordinate system, the coordinates of the tractor in the Cartesian coordinate system are obtained. Then, combined with the aforementioned physical model, the position of the trailer of the tractor at each sampling point can be inferred.

[0061] For a first trailer directly connected to the tractor, determining the trailer angle of the trailer when the tractor is located at each sampling point based on the tractor speed when the tractor is located at the corresponding sampling point may include: determining a heading angle difference between the tractor and the first trailer when the tractor is located at each sampling point; and for each sampling point, dividing the product of the tractor speed when the tractor is located at the sampling point, the sine of the heading angle difference, and the sampling time interval by a first distance between the connector and the trailer center of the first trailer to obtain the trailer angle of the first trailer when the tractor is located at the sampling point.

[0062] The calculation principle of the trailer angle of the first trailer can refer to formula (1), which will not be elaborated in this application.

[0063] For a second trailer indirectly connected to the tractor, determining the trailer angle of the trailer when the tractor is at the corresponding sampling point based on the tractor speed when the tractor is at each sampling point may include determining the trailer angle of the second trailer when the tractor is at the corresponding sampling point based on the tractor speed when the tractor is at each sampling point and the trailer angle of the previous trailer.

[0064] Specifically, the calculation principle of the trailer angle of the second trailer can refer to formula (2), which will not be described in detail in this application.

[0065] Similarly, after obtaining the trailer angle of any trailer, the position of the trailer when the tractor is at each sampling point can be determined by reverse calculation from the position of the tractor. For details, please refer to formula (3). Thus, the position of the trailer when the tractor is at each sampling point can be obtained.

[0066] At this time, collision detection can be performed on the towing trailer based on the position of the towing trailer.

[0067] Specifically, such as Figure 3 As shown, based on the position of the trailer, determining the obstacle situation in the area where the towing trailer is located, and based on the obstacle situation, determining the target path where the towing trailer does not collide in the initial sampling path, can include: steps S301 to S302.

[0068] Step S301 , based on the sampling points, the tractor size of the tractor, the position of the trailer, and the trailer size of the trailer, the area where the tractor trailer is located when the tractor is located at each sampling point is determined. When the number of obstacle point clouds in the area where the tractor trailer is located is less than or equal to a number threshold, the tractor trailer does not collide when the tractor is located at the corresponding sampling point.

[0069] In step S302 , if no collision occurs between the tractor and the trailer when the tractor is located at each sampling point of the initial sampling path, the initial sampling path is used as the target path.

[0070] Specifically, based on the sampling point (i.e., the position of the tractor), the tractor's tractor dimensions, the trailer's position, and the trailer's trailer dimensions, rectangles can be created, each representing a tractor and a trailer. Since the obstacle point cloud is known in advance, if a rectangle with a point cloud count greater than a threshold exists, it indicates that the tractor or trailer represented by the rectangle has collided, i.e., the tractor and trailer have collided. In this case, the initial sampling path containing the sampling point used to create the rectangle needs to be eliminated. The remaining pre-selected sampling paths can then be used as the target paths.

[0071] In some embodiments of the present application, if the number of the initial sampling paths without collision is one, the initial sampling path without collision can be used as the target path.

[0072] In other embodiments of the present application, if there are multiple initial sampling paths in which no collision occurs, determining a target path in which the tractor trailer does not collide among the initial sampling paths may include: using the initial sampling paths in which no collision occurs as alternative paths, determining a path score for each alternative path, and determining the target path among the multiple alternative paths based on the path score.

[0073] The path score is associated with the path length of the alternative path and / or the lateral offset of each sampling point passed by the alternative path.

[0074] In some embodiments of the present application, determining the path score of each alternative path may include: determining the offset difference of each sampling point compared to the previous sampling point based on the lateral offset of each sampling point passed by the alternative path; and determining the path score of each alternative path based on the path length of the alternative path, the lateral offset of each sampling point passed by the alternative path, and the offset difference.

[0075] Specifically, the path score can be expressed as cost = W length *length-W l *∑|l|-W l’ *∑|l′|. Where, length is the path length of the alternative path, ∑|l| is the sum of the lateral offsets of the sampling points passed by the alternative path in the Frenet coordinate system, and ∑|l′| is the sum of the lateral offset differences of the sampling points passed by the alternative path in the Frenet coordinate system. W length 、W l 、W l’ All are weights.

[0076] Accordingly, the alternative path with the highest score can be selected as the target path.

[0077] In the implementation of the present application, the motion state of a multi-section tractor trailer can be inferred, and the optimal, collision-free path can be selected as the target path using path sampling, collision detection, and scoring screening. This can avoid collisions between the trailer and obstacles and improve driving safety.

[0078] It should be noted that, for the sake of simplicity of description, the aforementioned method embodiments are all expressed as a series of action combinations. However, those skilled in the art should be aware that this application is not limited to the described order of actions, because according to this application, certain steps can be performed in other orders.

[0079] like Figure 4 FIG2 is a schematic structural diagram of a path planning device 400 provided in an embodiment of the present application, wherein the path planning device 400 is configured on a tractor trailer.

[0080] Specifically, the path planning device 400 may include:

[0081] The tractor position acquisition unit 401 is used to acquire the current position of the tractor;

[0082] A starting point determining unit 402 is configured to determine a starting point based on the current position;

[0083] The sampling point determination unit 403 is configured to perform sampling within a preset distance range starting from the starting point according to a preset distance step and a preset lateral offset step to obtain a sampling point;

[0084] A path sampling unit 404 is configured to perform polynomial fitting based on the starting point and the sampling points to obtain an initial sampling path;

[0085] a trailer position determining unit 405, configured to determine the trailer position of the trailer when the tractor is located at each sampling point;

[0086] The collision detection unit 406 is configured to determine the obstacle conditions in the area where the towing trailer is located based on the position of the towing trailer, and determine a target path for the towing trailer in the initial sampling path based on the obstacle conditions, in which the towing trailer does not collide.

[0087] In some embodiments of the present application, the collision detection unit 406 may be specifically configured to: determine, based on the sampling points, the tractor size of the tractor, the position of the trailer, and the trailer size of the trailer, the area where the tractor trailer is located when the tractor is located at each sampling point; when the number of obstacle point clouds in the area where the tractor trailer is located is less than or equal to a quantity threshold, the tractor trailer does not collide when the tractor is located at the corresponding sampling point; and if the tractor trailer does not collide when the tractor is located at each sampling point of the initial sampling path, the initial sampling path is used as the target path.

[0088] In some embodiments of the present application, if there are multiple initial sampling paths without collision, the collision detection unit 406 can be specifically used to: use the initial sampling paths without collision as alternative paths, determine the path score of each alternative path, and the path score is associated with the path length of the alternative path and / or the lateral offset of each sampling point passed by the alternative path; based on the path score, determine the target path among the multiple alternative paths.

[0089] In some embodiments of the present application, the collision detection unit 406 can be specifically used to: determine the offset difference of each sampling point compared to the previous sampling point based on the lateral offset of each sampling point passed by the alternative path; determine the path score of each alternative path based on the path length of the alternative path, the lateral offset of each sampling point passed by the alternative path, and the offset difference.

[0090] In some embodiments of the present application, the trailer position determination unit 405 may be specifically configured to: determine the trailer angle of the trailer when the tractor is located at the corresponding sampling point based on the tractor speed when the tractor is located at each sampling point; and determine the trailer position of the trailer when the tractor is located at each sampling point based on the trailer angle of the trailer when the tractor is located at each sampling point and the position of the sampling point.

[0091] In some embodiments of the present application, for a first trailer directly connected to the tractor, the trailer position determination unit 405 may be specifically configured to: determine a heading angle difference between the tractor and the first trailer when the tractor is located at each sampling point; and for each sampling point, divide the product of the tractor speed when the tractor is located at the sampling point, the sine value of the heading angle difference, and the sampling time interval by the first distance between the connector and the trailer center of the first trailer to obtain the trailer angle of the first trailer when the tractor is located at the sampling point.

[0092] In some embodiments of the present application, for a second trailer indirectly connected to the tractor, the trailer position determination unit 405 may be specifically configured to determine the trailer angle of the second trailer when the tractor is located at the corresponding sampling point based on the tractor speed when the tractor is located at each sampling point and the trailer angle of the previous trailer.

[0093] It should be noted that for the convenience and simplicity of description, the specific working process of the above-mentioned path planning device 400 can be referred to Figures 1 to 3 The corresponding process of the method will not be described in detail here.

[0094] like Figure 5 FIG2 is a schematic diagram of a tractor-trailer provided in an embodiment of the present application. Specifically, the tractor-trailer 5 may include a processor 50, a memory 51, and a computer program 52 stored in the memory 51 and executable on the processor 50, such as a path planning program. The tractor-trailer includes a tractor 53 and a trailer 54. When the tractor 53 moves, the trailer 54 is driven by a connector.

[0095] When the processor 50 executes the computer program 52, the steps in the above-mentioned path planning method embodiments are implemented, for example: Figure 1 Alternatively, when the processor 50 executes the computer program 52, the functions of the modules / units in the above-mentioned device embodiments are realized, for example, Figure 4 The functions of the tractor position acquisition unit 401, the starting point determination unit 402, the sampling point determination unit 403, the path sampling unit 404, the trailer position determination unit 405 and the collision detection unit 406 are shown.

[0096] The computer program may be divided into one or more modules / units, which are stored in the memory 51 and executed by the processor 50 to implement the present application. The one or more modules / units may be a series of computer program instruction segments capable of performing specific functions, and the instruction segments are used to describe the execution process of the computer program in the tractor-trailer.

[0097] For example, the computer program can be divided into: a tractor position acquisition unit, a starting point determination unit, a sampling point determination unit, a path sampling unit, a trailer position determination unit, and a collision detection unit. The specific functions of each unit are as follows: the tractor position acquisition unit is used to obtain the current position of the tractor; the starting point determination unit is used to determine the starting point based on the current position; the sampling point determination unit is used to sample from the starting point within a preset distance range according to a preset distance step and a lateral offset step to obtain sampling points; the path sampling unit is used to perform polynomial fitting based on the starting point and the sampling points to obtain an initial sampling path; the trailer position determination unit is used to determine the trailer position of the trailer when the tractor is located at each sampling point; the collision detection unit is used to determine the obstacle conditions in the area where the tractor trailer is located based on the trailer position, and based on the obstacle conditions, determine a target path for the tractor trailer to avoid collision within the initial sampling path.

[0098] The tractor trailer may include, but is not limited to, a processor 50 and a memory 51. It will be understood by those skilled in the art that Figure 5 It is only an example of a tractor trailer and does not constitute a limitation of the tractor trailer. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the tractor trailer may also include input and output devices, network access devices, buses, etc.

[0099] The processor 50 may be a central processing unit (CPU), other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), off-the-shelf programmable gate arrays or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor.

[0100] The memory 51 can be an internal storage unit of the tractor trailer, such as a hard drive or memory of the tractor trailer. The memory 51 can also be an external storage device of the tractor trailer, such as a plug-in hard drive, a Smart Media Card (SMC), a Secure Digital (SD) card, a flash memory card, etc. equipped on the tractor trailer. Furthermore, the memory 51 can include both an internal storage unit of the tractor trailer and an external storage device. The memory 51 is used to store the computer program and other programs and data required by the tractor trailer. The memory 51 can also be used to temporarily store data that has been output or is about to be output.

[0101] It should be noted that, for the convenience and brevity of description, the structure of the tractor trailer can also refer to the specific description of the structure in the method embodiment, which will not be repeated here.

[0102] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.

[0103] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant description of other embodiments.

[0104] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0105] In the embodiments provided herein, it should be understood that the disclosed devices / tractor trailers and methods can be implemented in other ways. For example, the device / tractor trailer embodiments described above are merely illustrative. For example, the division of modules or units is merely a logical functional division. In actual implementation, other division methods may be used, such as multiple units or components being combined or integrated into another system, or some features being ignored or not implemented. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interface, or the indirect coupling or communication connection of devices or units may be electrical, mechanical, or other forms.

[0106] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0107] In addition, the functional units in the various embodiments of the present application may be integrated into a single processing unit, or each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0108] If the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present application implements all or part of the process in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and when the computer program is executed by the processor, it can implement the steps of the above-mentioned various method embodiments. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal and software distribution medium. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electric carrier signals and telecommunication signals.

[0109] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present application, and should all be included in the scope of protection of the present application.

Claims

1. A path planning method, characterized in that: Applicable to a towing trailer, the towing trailer comprises a tractor and a trailer, and when the tractor moves, the trailer is driven to move by a connecting member; The path planning method comprises: Obtaining the current position of the tractor; determining a starting point based on the current position; Within the preset distance range, sampling is performed starting from the starting point according to the preset distance step and lateral offset step to obtain a sampling point; Performing polynomial fitting based on the starting point and the sampling points to obtain an initial sampling path; determining a trailer position of the trailer when the tractor is located at each sampling point; Based on the position of the trailer, an obstacle condition in the area where the towing trailer is located is determined, and based on the obstacle condition, a target path in which the towing trailer does not collide is determined in the initial sampling path.

2. The path planning method according to claim 1, wherein: The determining of obstacle conditions in the area where the towing trailer is located based on the position of the towing trailer, and determining a target path in which the towing trailer does not collide in the initial sampling path based on the obstacle conditions, includes: determining, based on the sampling points, the tractor size of the tractor, the position of the trailer, and the trailer size of the trailer, an area where the tractor trailer is located when the tractor is located at each sampling point, and when the number of obstacle point clouds in the area where the tractor trailer is located is less than or equal to a number threshold, the tractor trailer has not collided when the tractor is located at the corresponding sampling point; If no collision occurs between the tractor and the trailer when the tractor is located at each sampling point of the initial sampling path, the initial sampling path is used as the target path.

3. The path planning method according to claim 1, wherein: If there are multiple initial sampling paths where no collision occurs, determining a target path where no collision occurs for the tractor trailer among the initial sampling paths includes: Taking initial sampled paths without collision as candidate paths, determining a path score for each candidate path, wherein the path score is associated with the path length of the candidate path and / or the lateral offset of each sampling point passed by the candidate path; The target path is determined among the plurality of candidate paths based on the path scores.

4. The path planning method according to claim 3, wherein: Determining a path score for each of the candidate paths includes: Determining an offset difference between each sampling point and a previous sampling point based on the lateral offset of each sampling point passed by the alternative path; The path score of each of the candidate paths is determined based on the path length of the candidate path, the lateral offset of each sampling point passed by the candidate path, and the offset difference.

5. The path planning method according to claim 1, wherein: The determining of the trailer position of the trailer when the tractor is located at each sampling point includes: determining, based on the tractor speed when the tractor is located at each sampling point, a trailer angle of the trailer when the tractor is located at the corresponding sampling point; The trailer position of the trailer when the tractor is located at each sampling point is determined based on the trailer angle of the trailer when the tractor is located at each sampling point and the position of the sampling point.

6. The path planning method according to claim 5, wherein: For a first trailer directly connected to the tractor, determining a trailer angle of the tractor when the tractor is located at each sampling point based on the tractor speed when the tractor is located at the corresponding sampling point includes: determining a heading angle difference between the tractor and the first trailer when the tractor is located at each sampling point; For each sampling point, a product of the tractor speed, the sine value of the heading angle difference, and the sampling time interval when the tractor is located at the sampling point is divided by a first distance between the connector and the trailer center of the first trailer to obtain a trailer angle of the first trailer when the tractor is located at the sampling point.

7. The path planning method according to claim 5, wherein: For a second trailer indirectly connected to the tractor, determining the trailer angle of the tractor when the tractor is located at the corresponding sampling point based on the tractor speed when the tractor is located at each sampling point includes: Based on the tractor speed when the tractor is located at each sampling point and the trailer angle of the previous trailer, the trailer angle of the second trailer when the tractor is located at the corresponding sampling point is determined.

8. A path planning device, characterized in that: The tractor trailer is configured to include a tractor and a trailer. When the tractor moves, the trailer is driven to move by the connecting member. The path planning device comprises: A tractor position acquisition unit, configured to acquire the current position of the tractor; a starting point determining unit, configured to determine a starting point based on the current position; a sampling point determination unit, configured to perform sampling within a preset distance range, starting from the starting point and according to a preset distance step and a lateral offset step, to obtain a sampling point; a path sampling unit, configured to perform polynomial fitting based on the starting point and the sampling points to obtain an initial sampling path; a trailer position determining unit, configured to determine the trailer position of the trailer when the tractor is located at each sampling point; A collision detection unit is configured to determine an obstacle condition in an area where the towing trailer is located based on the position of the towing trailer, and to determine a target path in which the towing trailer does not collide within the initial sampling path based on the obstacle condition.

9. A tractor trailer, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: The tractor trailer includes a tractor and a trailer, and when the tractor moves, the trailer is driven to move by a connecting member; when the processor executes the computer program, the steps of the path planning method according to any one of claims 1 to 7 are implemented.

10. A computer program product, characterized in that The invention comprises a computer program, which enables the path planning method according to any one of claims 1 to 7 to be executed when the computer program is executed.

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