Vehicle U-turn path determination method and device and storage medium

Abstract

The invention discloses a vehicle U-turn path determination method and device and a storage medium, and the method comprises the steps: generating a U-turn reference line of a vehicle through map information; detecting that the vehicle currently enters a turn-round scene; a path tracking deviation state equation of the U-turn reference line is constructed so that the vehicle can track and control the U-turn reference line, and the path tracking deviation state equation represents the relation among any U-turn moment, the front wheel turning angle of the vehicle, the preview distance and the steering deviation in the U-turn process; the steering deviation at the turning-around moment is an included angle between the direction of a target point at the turning-around moment and the course angle of the vehicle at the turning-around moment, and the target point at the turning-around moment is a point on a turning-around reference line at a preview distance in front of the vehicle at the turning-around moment. In this way, accurate tracking control over the U-turn reference line can be achieved.

Description

Technical Field

[0001] The present application relates to the field of autonomous driving, and in particular to a method, device and storage medium for determining a vehicle turn path. Background Art

[0002] U-turn scenarios are the hub of urban traffic as the necessary points for vehicles to gather, turn and evacuate. With the development of map information processing and vehicle control technology, modern autonomous driving systems have begun to adopt more intelligent and flexible methods to plan and control U-turn paths. However, there are still some challenges in the existing U-turn path determination methods. How to achieve accurate tracking and control of the U-turn reference line is a technical problem that needs to be solved urgently. Summary of the invention

[0003] The main technical problem solved by the present application is to provide a method, device and computer-readable storage medium for determining a vehicle U-turn path, which can achieve accurate tracking and control of a U-turn reference line.

[0004] In order to solve the above technical problems, a technical solution adopted in the present application is: to provide a method for determining a vehicle U-turn path, the method comprising: using map information to generate a U-turn reference line for the vehicle; detecting that the vehicle currently enters a U-turn scene; constructing a path tracking deviation state equation for the U-turn reference line, so as to be used for the vehicle to track and control the U-turn reference line, wherein the path tracking deviation state equation characterizes the relationship between the front wheel turning angle, preview distance and steering deviation of the vehicle at any U-turn moment during the U-turn process, the steering deviation at the U-turn moment is the angle between the direction of the target point at the U-turn moment and the heading angle of the vehicle at the U-turn moment, and the target point at the U-turn moment is the point on the U-turn reference line at the preview distance in front of the vehicle at the U-turn moment.

[0005] Among them, in the path tracking deviation state equation, the steering deviation at the time of U-turn is equal to the arc tangent value of the target ratio, the target ratio is the ratio between the target product and the preview distance, the target product is the sine value of the front wheel turning angle at the time of U-turn multiplied by the first multiple of the vehicle's center axis, and the first multiple is greater than 1.

[0006] Among them, constructing the path tracking deviation state equation of the U-turn reference line includes: constructing the path tracking deviation state equation of the U-turn reference line based on the turning radius constraint of the vehicle on the U-turn reference line and the impact of the kinematic model on the performance of the vehicle, wherein the performance impact includes at least one of motion stability and steering characteristics.

[0007] Among them, based on the turning radius constraint of the vehicle on the U-turn reference line and the influence of the kinematic model on the performance of the vehicle, a path tracking deviation state equation of the U-turn reference line is constructed, including: using a two-degree-of-freedom vehicle model to construct a first relationship between the turning radius, the preview distance and the front wheel angle, the turning radius is the turning radius of the target point corresponding to the preview distance; using Ackerman steering geometry, constructing a second relationship between the turning radius and the steering deviation; combining the first relationship and the second relationship, converting to obtain the path tracking deviation state equation of the U-turn reference line.

[0008] Among them, in the first relationship, the reciprocal of the turning radius is equal to the ratio between the first multiple of the sine value of the front wheel turning angle and the preview distance; in the second relationship, the steering deviation is equal to the arc tangent value of the ratio of the vehicle's center axis to the turning radius.

[0009] Among them, the first multiple is 2.

[0010] The method of using map information to generate a U-turn reference line for the vehicle includes: using map information to obtain a target lane point set of the vehicle in a U-turn scenario; and smoothing the target lane point set to obtain the U-turn reference line.

[0011] Among them, using map information to obtain a target lane point set of the vehicle in the U-turn scenario, including: based on a memory map, obtaining the target lane point set of the vehicle in the U-turn scenario; and / or, smoothing the target lane point set to obtain a U-turn reference line, including: using a Bessel smoothing strategy to smooth the target lane point set to obtain a U-turn reference line.

[0012] Among them, detecting that the vehicle is currently entering a U-turn scenario includes: obtaining the current position of the vehicle, detecting that the distance between the current position and the stop line is less than or equal to a preset distance threshold; and / or the preview distance is a smaller value between a preset distance and the second multiple of the current speed of the vehicle.

[0013] To solve the above technical problems, another technical solution adopted in the present application is: to provide an electronic device, including a memory and a processor coupled to each other, the memory storing program instructions; the processor is used to execute the program instructions stored in the memory to implement the above vehicle U-turn path determination method.

[0014] In order to solve the above technical problems, another technical solution adopted by the present application is: providing a computer-readable storage medium, which is used to store program instructions, and the program instructions can be executed by a processor to implement the above vehicle U-turn path determination method.

[0015] The above scheme, while utilizing map information to generate the vehicle's U-turn reference line, and when detecting that the vehicle is currently entering a U-turn scenario, constructs a path tracking deviation state equation for the U-turn reference line, so as to be used by the vehicle to track and control the U-turn reference line. Among them, the path tracking deviation state equation characterizes the relationship between the vehicle's front wheel angle, preview distance, and steering deviation at any U-turn moment during the U-turn process. By constructing the path tracking deviation state equation for the U-turn reference line, the present application scheme can calculate in real time the relationship between the vehicle's front wheel angle, preview distance, and steering deviation during the U-turn process, which helps to achieve accurate tracking and control of the U-turn reference line. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a flow chart of an embodiment of a method for determining a vehicle U-turn path provided by the present application;

[0017] Figure 2 yes Figure 1 The flowchart of step S13 is shown as an embodiment;

[0018] Figure 3 It is a schematic diagram of an embodiment of tracking control of a U-turn reference line provided by the present application;

[0019] Figure 4 It is a schematic diagram of a framework of an embodiment of a vehicle U-turn path determination device provided by the present application;

[0020] Figure 5 It is a schematic diagram of a framework of an embodiment of an electronic device provided by the present application;

[0021] Figure 6 It is a schematic diagram of a framework of an embodiment of a computer-readable storage medium provided by the present application. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and effect of the present application clearer and more specific, the present application is further described in detail below with reference to the accompanying drawings and examples.

[0023] In the following description, for the purpose of explanation rather than limitation, specific details such as specific system structures, interfaces, and technologies are provided to facilitate a thorough understanding of the present application.

[0024] The term "and / or" in this article is only a description of the association relationship of associated objects, indicating that there may be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, "many" in this article means two or more than two. In addition, the term "at least one" in this article means any combination of at least two of any one or more of a plurality of. For example, including at least one of A, B, and C, it can mean including any one or more elements selected from the set consisting of A, B and C. "Several" means at least one. The terms "first", "second", etc. in the specification and claims of this article and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0025] See also Figure 1 , Figure 1 1 is a flow chart of an embodiment of a method for determining a vehicle U-turn path provided by the present application. It should be noted that if there are substantially the same results, the method of the present application is not limited to the method of determining a vehicle U-turn path provided by the present application. Figure 1 The process sequence shown is limited. Figure 1 As shown, the method comprises the following steps:

[0026] S11: Generate a U-turn reference line for the vehicle using the map information.

[0027] In one embodiment, map information may be used to first obtain a target lane point set of the vehicle in a U-turn scenario, and then the target lane point set is smoothed to obtain a U-turn reference line.

[0028] In one implementation, the U-turn reference line is obtained by smoothing the target lane point set using a Bezier smoothing strategy.

[0029] The basic principle of smoothing the target lane point set using the Bessel smoothing strategy is explained as follows:

[0030] For example, the target lane point set contains four points A (P0), B (P1), C (P2) and D (P3) forming line segments AB, BC and CD.

[0031] in:

[0032] M=AB=(1-t)A+tB

[0033] N=BC=(1-t)B+tC

[0034] Q=CD=(1-t)C+tD

[0035] S=MN=(1-t)M+tN

[0036] T=NQ=(1-t)N+tQ

[0037] P=(1-t)S+tT

[0038] That is, P=(1-t)*((1-t)M+tN)+t*((1-t)N+tQ)

[0039] =(1-t)*((1-t)*((1-t)A+tB)+t*((1-t)B+tC))+t*((1-t)N+t*((1-t)C+tD))

[0040] =A(1-t) 3 +3Bt(1-t) 2 +3Ct 2 (1-t) 1 +Dt 3 (1-t) 0

[0041] =P0(1-t) 3 +3P1t(1-t) 2 +3P2t 2 (1-t) 1 +P3t 3 (1-t) 0

[0042] Among them, t belongs to 0 and 1. The Bezier curve is a mathematical curve used in two-dimensional graphics applications. It is determined by a set of vectors called control points. The given control points are connected in sequence to form a control polygon. The Bezier curve approximates this polygon and then changes the shape of the curve by adjusting the coordinates of the control points.

[0043] That is, the above equation can be used to smooth A(P0), B(P1), C(P2) and D(P3) in the target lane point set to obtain the corresponding smooth curve, which can be used as a reference line for U-turn.

[0044] Of course, in other embodiments, the target lane point set may be smoothed based on an interpolation smoothing method or a fitting smoothing method to obtain a U-turn reference line.

[0045] For example, based on the target lane point set, a Lagrangian polynomial is constructed so that the polynomial can pass through all the point sets, thereby obtaining a smooth curve as a reference line.

[0046] For another example, the target lane point set is divided into several segments, each segment is fitted with a polynomial, and the multiple curves obtained by fitting are spliced ​​to obtain a smooth curve as a reference line.

[0047] The above map can be a memory map of the driving environment constructed using the intelligent visual sensors of surrounding vehicles, or a high-precision map constructed including the vehicle's driving environment. In one implementation scenario, considering that the construction of a high-precision map requires a professional data collection vehicle, and the amount of calculation in the process of loading and using the high-precision map is large and the implementation technology is high, it is possible to choose to construct a memory map, and then obtain the target lane point set of the vehicle in the U-turn scenario based on the constructed memory map.

[0048] Optionally, the target lane point set can be a set of points on a navigation path obtained by navigating the current position and the target destination based on a constructed memory map; or a set of points sampled on the road starting from the current position based on a constructed memory map. The target lane point set can be determined according to actual needs and is not specifically limited here.

[0049] In one implementation scenario, step S11 is performed when it is determined that a U-turn is possible ahead (for example, there is an intersection where a U-turn is possible) based on the constructed map.

[0050] In one implementation scenario, before step S11, it is necessary to determine the quality of the road information represented by the environmental elements in the constructed map. If the quality of the road information is poor (for example, there is no road in the map, or the road in the map does not match the normal road, etc.), step S11 is not executed.

[0051] S12: It is detected that the vehicle is currently entering a U-turn scenario.

[0052] In one embodiment, the current position of the vehicle may be obtained first, and when it is detected that the distance between the current position of the vehicle and the stop line is less than or equal to a preset distance threshold, it is determined that the vehicle is currently entering a U-turn scenario. The specific preset distance threshold may be pre-set according to actual needs, such as 50 meters or 60 meters.

[0053] Of course, it is also possible to confirm that the vehicle is currently entering a U-turn scenario when it is determined that a U-turn is possible ahead. The method of detecting that the vehicle is currently entering a U-turn scenario can be determined according to actual needs.

[0054] S13: constructing a path tracking deviation state equation of the U-turn reference line, so as to be used for the vehicle to track the U-turn reference line.

[0055] In this embodiment, the path tracking deviation state equation is used for the vehicle to track and control the generated U-turn reference line to determine the path points that the vehicle should pass through at each U-turn moment, wherein the path points that the vehicle should pass through at each U-turn moment are the path points on the vehicle's U-turn path.

[0056] Among them, the path tracking deviation state equation characterizes the relationship between the front wheel turning angle, preview distance and steering deviation of the vehicle at any U-turn moment during the U-turn process. The steering deviation at the U-turn moment is the angle between the direction of the target point at the U-turn moment and the heading angle of the vehicle at the U-turn moment. The target point at the U-turn moment is the point on the U-turn reference line at the preview distance in front of the vehicle at the U-turn moment. It should be noted that by constructing the path tracking deviation state equation of the U-turn reference line, the relationship between the front wheel turning angle, preview distance and steering deviation of the vehicle during the U-turn process can be calculated in real time, which helps to achieve accurate tracking control of the U-turn reference line.

[0057] In one embodiment, in the path tracking deviation state equation, the steering deviation at the time of U-turn is equal to the arc tangent value of the target ratio, the target ratio is the ratio between the target product and the preview distance, the target product is the sine value of the front wheel turning angle at the time of U-turn multiplied by the first multiple of the center axis of the vehicle, and the first multiple is greater than 1.

[0058] Exemplarily, the path tracking deviation state equation is expressed as follows:

[0059]

[0060] Wherein, δ(t) represents the steering deviation at the time of U-turn, Ld represents the preview distance, and nLsin(a(t) represents the target product. Wherein, a(t) represents the front wheel turning angle at the time of U-turn, L represents the center axis (wheelbase) of the vehicle, and n is the first multiple, and n is greater than 1. In a specific embodiment, the value of the first multiple is 2.

[0061] It should be noted that the relationship between the preview distance and the tracking of the U-turn reference line is: a preview distance value that is too small will lead to unstable tracking, and a preview distance value that is too large will affect the tracking effect. Among them, when the vehicle tracks a desired trajectory composed of discrete points, it will first select a point that is a certain distance from the vehicle, and then control the steering wheel to make the vehicle reach this point, and then reach the subsequent points one by one in the same way until the entire trajectory is tracked. The "certain distance" here is the preview distance.

[0062] In one embodiment, the selection of the preview distance should match the vehicle speed to ensure that the vehicle is stable and safe when tracking the path. Exemplarily, the preview distance is the smaller value of the preset distance and the second multiple of the current speed of the vehicle. The specific second multiple can be set according to actual needs, for example, the second multiple is 0.1, 0.3 or 0.5, etc.

[0063] It should be noted that, since the path tracking deviation state equation can characterize the relationship between the vehicle's front wheel turning angle, preview distance and steering deviation at any U-turn moment during the U-turn process, and the preview distance is closely related to the vehicle's current speed, the vehicle's driving state can be adjusted under different driving conditions to improve the vehicle's efficiency in passing through the U-turn scenario.

[0064] In one embodiment, the path tracking deviation state equation is constructed based on the turning radius constraint of the vehicle on the U-turn reference line and the influence of the kinematic model on the performance of the vehicle. The performance influence includes at least one of motion stability and steering characteristics. In this embodiment, the U-turn reference line is tracked and controlled using the constructed path tracking deviation state equation, so that each path point on the vehicle U-turn path determined in the tracking control of the U-turn reference line satisfies the turning radius constraint and the kinematic constraint.

[0065] Specifically, see Figure 2 , Figure 2 yes Figure 1 The flowchart of step S13 is shown as an embodiment. In this embodiment, the path tracking deviation state equation of the U-turn reference line is constructed based on the turning radius constraint of the vehicle on the U-turn reference line and the influence of the kinematic model on the performance of the vehicle, and specifically includes the following steps:

[0066] S21: Using a two-degree-of-freedom vehicle model, a first relationship among a turning radius, a preview distance, and a front wheel turning angle is constructed, wherein the turning radius is a turning radius of a target point corresponding to the preview distance.

[0067] In the first relationship, the reciprocal of the turning radius is equal to the ratio of the first multiple of the sine value of the front wheel turning angle to the preview distance. Exemplarily, the first relationship can be expressed as follows:

[0068]

[0069] Wherein, R represents the turning radius of the target point, Ld represents the preview distance, and a represents the front wheel turning angle. The first multiple is 2. In other embodiments, the first multiple can also be other values, such as 1.5 or 1.8.

[0070] The following is a brief introduction on how to use the two-degree-of-freedom vehicle model to construct the first relationship between the turning radius, preview distance and front wheel turning angle.

[0071] For example, see Figure 3 , Figure 3 FIG. 1 is a schematic diagram of an embodiment of tracking control of a U-turn reference line provided by the present application. Figure 3As shown in the figure, R represents the turning radius of the target point, Ld represents the preview distance, a represents the front wheel turning angle, and L represents the vehicle wheelbase. The target point on the U-turn reference line can be obtained through the preview distance. Specifically, the target point is a point on the U-turn reference line at the preview distance in front of the vehicle at the moment of the U-turn.

[0072] first, Figure 3 The relationship between the turning radius R, preview distance Ld, and front wheel turning angle a of the target point shown is as follows:

[0073]

[0074] Transform the above relationship as follows:

[0075]

[0076]

[0077]

[0078] According to the above steps, a first relationship among the turning radius, the preview distance and the front wheel turning angle is constructed.

[0079] S22: Using Ackerman steering geometry, a second relationship between turning radius and steering deviation is constructed.

[0080] Among them, in the second relationship, the steering deviation is equal to the arc tangent value of the ratio of the vehicle's center axis to the turning radius. The second relationship can be expressed as follows:

[0081]

[0082] S23: Combining the first relationship and the second relationship, converting and obtaining a path tracking deviation state equation of the U-turn reference line.

[0083] Specifically, the first relationship constructed is brought into the second relationship constructed, and then the time variable representing any U-turn moment is added to convert the path tracking deviation state equation of the U-turn reference line. The path tracking deviation state equation of the U-turn reference line can be expressed as follows:

[0084]

[0085] In this embodiment, after determining the path tracking deviation state equation, the path tracking deviation state equation is used to track and control the generated U-turn reference line to determine the path points that the vehicle should pass through at each U-turn moment, wherein the path points that the vehicle should pass through at each U-turn moment are the path points on the vehicle's U-turn path.

[0086] The above scheme, while utilizing map information to generate the vehicle's U-turn reference line, and when detecting that the vehicle is currently entering a U-turn scene, constructs a path tracking deviation state equation for the U-turn reference line, so as to be used by the vehicle to track and control the U-turn reference line. Among them, the path tracking deviation state equation characterizes the relationship between the vehicle's front wheel angle, preview distance, and steering deviation at any U-turn moment during the U-turn process. By constructing the path tracking deviation state equation for the U-turn reference line, the present application scheme can calculate in real time the relationship between the vehicle's front wheel angle, preview distance, and steering deviation during the U-turn process, which helps to achieve precise tracking and control of the U-turn reference line, and further facilitates accurate determination of each path point on the U-turn path.

[0087] See also Figure 4 , Figure 4 It is a framework schematic diagram of an embodiment of a vehicle U-turn path determination device provided by the present application. In this embodiment, the vehicle U-turn path determination device 40 includes: a reference line generation module 41, a detection module 42 and a tracking control module 43. Among them, the reference line generation module 41 is used to generate a U-turn reference line of the vehicle using map information; the detection module 42 is used to detect that the vehicle currently enters a U-turn scene; the tracking control module 43 is used to construct a path tracking deviation state equation of the U-turn reference line, so as to be used for the vehicle to track and control the U-turn reference line, wherein the path tracking deviation state equation characterizes the relationship between the front wheel turning angle, the preview distance and the steering deviation of the vehicle at any U-turn moment during the U-turn process, the steering deviation at the U-turn moment is the angle between the direction of the target point at the U-turn moment and the heading angle of the vehicle at the U-turn moment, and the target point at the U-turn moment is the point on the U-turn reference line at the preview distance in front of the vehicle at the U-turn moment.

[0088] In some embodiments, in the path tracking deviation state equation constructed by the tracking control module 43, the steering deviation at the moment of U-turn is equal to the arc tangent value of the target ratio, the target ratio is the ratio between the target product and the preview distance, the target product is the sine value of the front wheel turning angle at the moment of U-turn multiplied by the first multiple of the center axis of the vehicle, and the first multiple is greater than 1.

[0089] In some embodiments, the tracking control module 43 constructs a path tracking deviation state equation for the U-turn reference line, including: based on the turning radius constraint of the vehicle on the U-turn reference line and the impact of the kinematic model on the performance of the vehicle, constructing a path tracking deviation state equation for the U-turn reference line, wherein the performance impact includes at least one of motion stability and steering characteristics.

[0090] In some embodiments, based on the turning radius constraint of the vehicle on the U-turn reference line and the impact of the kinematic model on the vehicle's performance, a path tracking deviation state equation for the U-turn reference line is constructed, including: using a two-degree-of-freedom vehicle model to construct a first relationship between the turning radius, the preview distance and the front wheel angle, the turning radius being the turning radius of the target point corresponding to the preview distance; using Ackerman steering geometry to construct a second relationship between the turning radius and the steering deviation; combining the first relationship and the second relationship to convert and obtain the path tracking deviation state equation for the U-turn reference line.

[0091] In some embodiments, in a first relationship, the inverse of the turning radius is equal to the ratio of a first multiple of the sine value of the front wheel turning angle to the preview distance; in a second relationship, the steering deviation is equal to the arc tangent of the ratio of the vehicle's center axis to the turning radius.

[0092] In some embodiments, the first multiple is 2.

[0093] In some embodiments, the reference line generation module 41 generates a U-turn reference line for the vehicle using map information, including: using map information to obtain a target lane point set for the vehicle in a U-turn scenario; and smoothing the target lane point set to obtain a U-turn reference line.

[0094] In some embodiments, map information is used to obtain a target lane point set for a vehicle in a U-turn scenario, including: based on a memory map, obtaining a target lane point set for the vehicle in a U-turn scenario; and / or, the target lane point set is smoothed to obtain a U-turn reference line, including: using a Bessel smoothing strategy to smooth the target lane point set to obtain a U-turn reference line.

[0095] In some embodiments, the detection module 42 detects that the vehicle is currently entering a U-turn scenario, including: obtaining the current position of the vehicle, detecting that the distance between the current position and the stop line is less than or equal to a preset distance threshold; and / or, the preview distance is the smaller value of the preset distance and the second multiple of the current speed of the vehicle.

[0096] It should be noted that the device of this embodiment can execute the steps in the above method. For detailed description of the relevant content, please refer to the above method part, which will not be repeated here.

[0097] See also Figure 5 , Figure 5 1 is a schematic diagram of a framework of an electronic device according to an embodiment of the present application. In this embodiment, the electronic device 50 includes a memory 51 and a processor 52 .

[0098] The processor 52 may also be referred to as a CPU (Central Processing Unit). The processor 52 may be an integrated circuit chip having signal processing capabilities. The processor 52 may also be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components. The general-purpose processor may be a microprocessor or the processor 52 may also be any conventional processor 52, etc.

[0099] The memory 51 in the electronic device 50 is used to store program instructions required for the processor 52 to run.

[0100] The processor 52 is used to execute program instructions to implement the vehicle U-turn path determination method in the present application.

[0101] See also Figure 6 , Figure 6 It is a schematic diagram of a framework of an embodiment of a computer-readable storage medium provided by the present application. The computer-readable storage medium 60 of the embodiment of the present application stores a program instruction 61, and when the program instruction 61 is executed, the vehicle U-turn path determination method provided by the present application is implemented. Among them, the program instruction 61 can form a program file and be stored in the above-mentioned computer-readable storage medium 60 in the form of a software product, so that a computer device (which can be a personal computer, a server, or a network device, etc.) executes all or part of the steps of each implementation method of the present application. The aforementioned computer-readable storage medium 60 includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a disk or an optical disk, or a terminal device such as a computer, a server, a mobile phone, and a tablet.

[0102] The above scheme, while utilizing map information to generate the vehicle's U-turn reference line, and when detecting that the vehicle is currently entering a U-turn scenario, constructs a path tracking deviation state equation for the U-turn reference line, so as to be used by the vehicle to track and control the U-turn reference line. Among them, the path tracking deviation state equation characterizes the relationship between the vehicle's front wheel angle, preview distance, and steering deviation at any U-turn moment during the U-turn process. By constructing the path tracking deviation state equation for the U-turn reference line, the present application scheme can calculate in real time the relationship between the vehicle's front wheel angle, preview distance, and steering deviation during the U-turn process, which helps to achieve accurate tracking and control of the U-turn reference line.

[0103] In some embodiments, the functions or modules included in the device provided by the embodiments of the present disclosure can be used to execute the method described in the above method embodiments. The specific implementation can refer to the description of the above method embodiments, and for the sake of brevity, it will not be repeated here.

[0104] The above description of various embodiments tends to emphasize the differences between the various embodiments. The same or similar aspects can be referenced to each other, and for the sake of brevity, they will not be repeated herein.

[0105] In the several embodiments provided in the present application, it should be understood that the disclosed methods, devices and systems can be implemented in other ways. For example, the device implementation described above is only schematic. For example, the division of modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, and the indirect coupling or communication connection of devices or units can be electrical, mechanical or other forms.

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

[0107] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0108] If the integrated 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. With this understanding, the technical solution of the present application, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, server, or network device, etc.) or a processor to perform all or part of the steps of each implementation method of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program code.

[0109] The above description is only an implementation method of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method for determining a vehicle U-turn path, characterized in that: include: Using map information, generate a U-turn reference line for the vehicle; Detecting that the vehicle currently enters a U-turn scenario; A path tracking deviation state equation of the U-turn reference line is constructed for the vehicle to track and control the U-turn reference line, wherein the path tracking deviation state equation characterizes the relationship between the front wheel turning angle, preview distance and steering deviation of the vehicle at any U-turn moment in the U-turn process, the steering deviation at the U-turn moment is the angle between the direction of the target point at the U-turn moment and the heading angle of the vehicle at the U-turn moment, and the target point at the U-turn moment is the point on the U-turn reference line at the preview distance in front of the vehicle at the U-turn moment.

2. The method according to claim 1, characterized in that In the path tracking deviation state equation, the steering deviation at the moment of the U-turn is equal to the arc tangent value of the target ratio, the target ratio is the ratio between the target product and the preview distance, the target product is the sine value of the front wheel turning angle at the moment of the U-turn multiplied by the first multiple of the center axis of the vehicle, and the first multiple is greater than 1.

3. The method according to claim 1, characterized in that The step of constructing the path tracking deviation state equation of the U-turn reference line includes: Based on the turning radius constraint of the vehicle on the U-turn reference line and the impact of the kinematic model on the vehicle's performance, a path tracking deviation state equation of the U-turn reference line is constructed, wherein the performance impact includes at least one of motion stability and steering characteristics.

4. The method according to claim 3, characterized in that The path tracking deviation state equation of the U-turn reference line is constructed based on the turning radius constraint of the vehicle on the U-turn reference line and the influence of the kinematic model on the performance of the vehicle, including: Using a two-degree-of-freedom vehicle model, constructing a first relationship between the turning radius, the preview distance, and the front wheel turning angle, wherein the turning radius is a turning radius of the target point corresponding to the preview distance; constructing a second relationship between the turning radius and the steering deviation using Ackerman steering geometry; The first relationship and the second relationship are combined to obtain a path tracking deviation state equation of the U-turn reference line.

5. The method according to claim 4, characterized in that In the first relationship, the reciprocal of the turning radius is equal to the ratio between the first multiple of the sine value of the front wheel turning angle and the preview distance; In the second relationship, the steering deviation is equal to an arc tangent of a ratio of a center axis of the vehicle to the turning radius.

6. The method according to claim 2 or 5, characterized in that: The first multiple is 2.

7. The method according to claim 1, characterized in that The method of using the map information to generate a U-turn reference line for the vehicle includes: Using the map information, obtaining a target lane point set of the vehicle in the U-turn scenario; The target lane point set is smoothed to obtain the U-turn reference line.

8. The method according to claim 7, characterized in that The method of using map information to obtain a target lane point set of the vehicle in a U-turn scenario includes: Based on the memory map, a target lane point set of the vehicle in the U-turn scenario is obtained; And / or, the smoothing of the target lane point set to obtain the U-turn reference line includes: The target lane point set is smoothed using a Bezier smoothing strategy to obtain the U-turn reference line.

9. The method according to claim 1, characterized in that: The detecting that the vehicle currently enters a U-turn scenario includes: Acquiring the current position of the vehicle, and detecting that the distance between the current position and the stop line is less than or equal to a preset distance threshold; And / or, the preview distance is a smaller value between a preset distance and a second multiple of the current speed of the vehicle.

10. An electronic device, characterized in that: comprising a memory and a processor coupled to each other, The memory stores program instructions; The processor is used to execute the program instructions stored in the memory to implement the method according to any one of claims 1 to 9.

11. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores program instructions that can be run by a processor, and the program instructions can be executed by the processor to implement the method according to any one of claims 1 to 9.

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