CN114802212A

CN114802212A - Split type vehicle parking path planning method, device, equipment and medium

Info

Publication number: CN114802212A
Application number: CN202210513130.XA
Authority: CN
Inventors: 张沐豪; 靳欣宇
Original assignee: Beijing Zhuxian Technology Co Ltd
Current assignee: Beijing Zhuxian Technology Co Ltd
Priority date: 2022-05-12
Filing date: 2022-05-12
Publication date: 2022-07-29

Abstract

The embodiment of the application provides a parking path planning method, a parking path planning device, equipment and a parking path planning medium for split vehicles, and the method can be applied to the scenes of ports, high speeds, ports, mines, logistics transportation or urban traffic and the like. The method comprises the following steps: determining a starting point and a target point of split vehicle parking on a pre-established parking scene coordinate system; determining a first path between the starting point and the target point; calculating a trailer course angle and an articulation angle corresponding to each track point on the first path according to the head vehicle course angle of the starting point and the trailer course angle, wherein the articulation angle is a difference value between the trailer course angle and the head vehicle course angle; and determining a target parking path of the split vehicle according to the trailer course angle and the articulation angle. By the method, the finally obtained target parking path can be matched with the structure of the split vehicle, so that the split vehicle can be straightly thrown when reaching the parking position according to the target parking path, and the parking standard is met.

Description

Split type vehicle parking path planning method, device, equipment and medium

Technical Field

The application belongs to the field of automatic driving, and particularly relates to a parking path planning method, device, equipment and medium for a split vehicle, which can be applied to the scenes of ports, high speed, logistics, mines, closed parks, urban traffic and the like.

Background

In recent years, with the development of automated driving technology, automated driving vehicles have come to the ground and operated in harbors, high-speed scenes, and the like, and in these scenes, it is also necessary to complete the entire automated driving system by providing an autonomous parking function in open roads such as parking lots.

When an autonomous vehicle parks autonomously, the autonomous vehicle first stops at a starting point for parking and selects an autonomous parking function on the vehicle. Then, a parking path planning device for automatically driving the vehicle acquires a starting point and a stopping point of parking, and generates a parking path between the starting point and the stopping point by using a reeds-shepp curve. And then, performing collision detection on the generated parking path, and if no collision exists, outputting the parking path so as to automatically drive the vehicle to park according to the parking path. However, unlike the compact body of a passenger car, a split-type vehicle such as a truck is divided into a towing head car and a trailer, which are connected by a towing pin of the head car, so that a certain angle is formed between the head car and the trailer of the vehicle during traveling. When the split type vehicle autonomously parks by utilizing the prior art, when the vehicle reaches a parking point according to a parking path, a trailer of the vehicle is not necessarily thrown straight, and a large included angle is possibly formed between the trailer and a head vehicle, so that the parking state is not only not in accordance with parking regulations, but also possibly generates parking risks.

Disclosure of Invention

The embodiment of the application provides a parking path planning method, a parking path planning device, equipment and a parking path planning medium for a split vehicle, which are used for solving the technical problem that a large included angle exists between a head vehicle and a trailer when the split vehicle parks autonomously.

In a first aspect, the present application provides a parking path planning method for a split vehicle, where the split vehicle includes a trailer and a head car driving the trailer to travel, and includes:

determining a starting point and a target point of the split vehicle parking on a pre-established parking scene coordinate system;

determining a first path between the starting point and the target point;

calculating a trailer course angle and an articulation angle corresponding to each track point on the first path according to the head vehicle course angle and the trailer course angle of the starting point, wherein the articulation angle is a difference value between the trailer course angle and the head vehicle course angle;

and determining a target parking path of the split vehicle according to the trailer course angle and the articulation angle.

In the embodiment, after the first path between the starting point and the target point is determined, the target parking path in the first path is determined according to the trailer course angle and the articulation angle corresponding to the track point on each path. The path is restrained and limited by the aid of the trailer course angle and the hinge angle, the finally obtained target parking path can be matched with the structure of the split vehicle, the split vehicle can be straightened when reaching the parking position according to the target parking path, parking specifications are met, and the problem that parking hidden danger is generated due to the fact that a large included angle exists between the head vehicle and the trailer is avoided.

In a possible embodiment, the determining the target parking path of the split vehicle according to the trailer heading angle and the articulation angle specifically includes:

sequencing the first paths according to the sequence of the lengths from small to large to generate a first path sequence;

sequentially judging whether a second path with the hinge angles corresponding to the track points smaller than a hinge angle threshold exists in the first path sequence;

if so, determining a target parking path of the split vehicle according to the trailer course angle;

if not, determining the target point to be measured of the starting point according to a preset step length and the loss value, and taking the target point to be measured as a new starting point to re-execute the step of determining the first path between the starting point and the target point until determining the target parking path of the split vehicle.

In this embodiment, after determining and sorting the first path between the start point and the target point, it may be determined whether a second path in which the articulation angle corresponding to each trajectory point is smaller than the articulation angle threshold exists in the first path sequence, that is, whether the articulation angle constraint is satisfied. If so, whether the trailer course angles corresponding to the track points on the second path are all smaller than the course angle threshold value or not can be continuously judged, namely whether the trailer course angle constraint is met or not can be continuously judged. If the constraint of the trailer course angle is met, collision detection can be continuously carried out on the second path, and if no collision exists between the second path and the obstacle, the second path is the target parking path. Through the arrangement, the finally obtained target parking path can meet the preset constraint condition and the collision detection.

In a possible implementation manner, the determining a target parking path of the split vehicle according to the trailer heading angle specifically includes:

judging whether the trailer course angles corresponding to the track points on the second path are all smaller than a course angle threshold value;

if so, performing collision detection on the second path to determine a target parking path of the split vehicle;

if not, continuing to execute the step of sequentially judging whether a second path with the articulation angle which is smaller than the articulation angle threshold value and corresponds to each track point exists in the first path sequence.

In the embodiment, the trailer course angle of the target parking path is constrained by judging whether the trailer course angles corresponding to the track points on the second path are all smaller than a course angle threshold value, namely whether the preset trailer course angle constraint is met, so that the finally obtained target parking path can meet the preset trailer course angle constraint. The trailer course angle when the split type vehicle is positioned at the target point can be limited within a certain range by limiting the trailer course angle, so that the trailer can be straightly thrown.

In a possible implementation manner, the performing collision detection on the second path to determine a target parking path of the split type vehicle specifically includes:

determining position information of an obstacle with a distance to the second path smaller than a preset distance;

determining whether the split type vehicle collides with the obstacle according to the position information of the obstacle and the geometry of the split type vehicle;

if yes, continuing to execute the step of sequentially judging whether a second path with the articulation angle corresponding to each track point smaller than the articulation angle threshold exists in the first path sequence;

and if not, determining the target parking path of the split type vehicle according to the second path.

In the embodiment, when performing collision detection on the second path, the position information of the obstacle which may have a collision risk with the vehicle on the second path may be determined first, and then whether the split type vehicle collides with the obstacle may be determined simply and accurately according to the position information of the obstacle and the geometry of the split type vehicle.

In a possible implementation manner, the determining the target point to be measured of the starting point according to a preset step length and a loss value specifically includes:

determining initial points to be measured of the starting point according to a preset step length and a plurality of head front wheel deflection angles;

acquiring state information of the split type vehicle at each initial point to be measured, wherein the state information comprises the length of a path which the split type vehicle has traveled, the steering angle amplitude of a steering wheel of the split type vehicle, the steering angle amplitude increment, the switching frequency of gears of the split type vehicle, the distance between the split type vehicle and a target point, an articulation angle and steering of the steering wheel;

determining a sub-loss value corresponding to the state information of each initial point to be measured according to a preset corresponding relation between the state information and the sub-loss value;

summing up the sub-loss values corresponding to each initial point to be measured to determine the loss value of each initial point to be measured;

and determining a target point to be measured according to the initial point to be measured with the minimum loss value.

In this embodiment, by setting a series of front wheel deflection angles, a series of adjacent points around the starting point, that is, the initial point to be measured, can be determined according to the preset step length and the front wheel deflection angles. And then calculating the loss value of each initial point to be measured, namely simply and accurately determining the target point to be measured with the minimum loss value. Furthermore, the size of the articulation angle and the driving posture are limited by adding the articulation angle and steering of the steering wheel in the state information, the initial point to be measured with the large articulation angle or the incorrect steering of the steering wheel is eliminated, and the efficiency of obtaining the target point to be measured with the minimum loss value from a series of initial points to be measured is improved.

In a possible implementation manner, the determining an initial point to be measured of the starting point according to a preset step length and a front wheel slip angle of a head specifically includes:

determining the abscissa of the initial point to be measured according to a preset step length, the abscissa of the starting point and the heading angle of the head vehicle of the starting point;

determining the vertical coordinate of the initial point to be measured according to a preset step length, the vertical coordinate of the initial point and the head vehicle course angle of the initial point;

determining the head vehicle course angle of the initial point to be measured according to a preset step length, the head vehicle course angle of the starting point, the head vehicle wheel base and the head vehicle front wheel deflection angle;

and determining the trailer course angle of the initial point to be measured according to a preset step length, the head vehicle course angle of the initial point, the trailer course angle of the initial point and the trailer wheelbase.

In this embodiment, the position coordinate may be obtained by first calculating according to a preset step length, the coordinate of the start point, and the heading angle of the head vehicle of the start point; calculating according to the preset step length, the head vehicle heading angle of the starting point, the head vehicle wheelbase and the head vehicle front wheel deflection angle to obtain a head vehicle heading angle; and calculating to obtain the trailer course angle according to the preset step length, the head vehicle course angle of the starting point, the trailer course angle of the starting point and the trailer wheelbase. After the position coordinate, the head vehicle course angle and the trailer course angle are obtained through calculation, the initial point to be measured of the starting point can be simply and accurately determined according to the three items.

In a possible implementation manner, the calculating a trailer heading angle and an articulation angle corresponding to each track point on the first path according to the head vehicle heading angle and the trailer heading angle of the starting point specifically includes:

determining a head vehicle heading angle corresponding to each track point according to an included angle between the tangential direction of each track point on the first path and the horizontal axis;

determining the trailer course angle corresponding to each track point according to a preset step length, the trailer wheelbase, the head vehicle course angle corresponding to each track point, the head vehicle course angle of the starting point and the trailer course angle;

and determining the articulation angle corresponding to each track point according to the difference between the head vehicle course angle and the trailer course angle corresponding to each track point.

In this embodiment, when the first path, that is, the curve is known, the tangent line of each track point on the first path can be obtained, so that the included angle between each tangent line of the track point and the horizontal axis of the coordinate system, that is, the heading angle of the head car corresponding to each track point can be obtained. After establishing the parking scene coordinate system and determining the starting point, the head vehicle heading angle of the starting point and the trailer heading angle can be obtained therewith, and can be considered to be known. Under the condition that the preset step length, the wheelbase of the trailer, the head vehicle course angle of the starting point, the trailer course angle and the head vehicle course angle corresponding to each track point are known, the trailer course angle corresponding to each track point can be simply and accurately calculated according to the known step length and the known trailer course angle. Under the condition that the heading angle of the head vehicle and the heading angle of the trailer corresponding to each track point are known, the articulation angle corresponding to each track point can be simply and accurately calculated.

In a second aspect, the present application provides a parking path planning apparatus for a split vehicle, comprising:

the position determining module is used for determining a starting point and a target point of the split vehicle parking on a pre-established parking scene coordinate system;

the path generation module is used for determining a first path between the starting point and the target point;

the angle calculation module is used for calculating a trailer course angle and an articulation angle corresponding to each track point on the first path according to the head vehicle course angle of the starting point and the trailer course angle, wherein the articulation angle is a difference value between the trailer course angle and the head vehicle course angle;

and the path determining module is used for determining a target parking path of the split vehicle according to the trailer course angle and the articulation angle.

In a possible embodiment, the path planning means is configured to implement the first aspect or any one of the possible implementations of the first aspect.

In a third aspect, the present application provides a parking path planning apparatus for a split vehicle, comprising: a processor, and a memory communicatively coupled to the processor;

the memory stores computer-executable instructions;

the processor executes the computer-executable instructions stored by the memory to implement the methods described above.

In a fourth aspect, the present application provides a computer-readable storage medium having stored thereon computer-executable instructions for implementing the above-mentioned method when executed by a processor.

In a fifth aspect, the present application provides a computer program product comprising a computer program which, when executed by a processor, implements the method described above.

Drawings

FIG. 1 is a schematic diagram of a split-type vehicle autonomous parking process;

FIG. 2 is a schematic diagram illustrating an autonomous parking process according to an embodiment of the present application;

fig. 3 is a flowchart of a parking path planning method for a split vehicle according to an embodiment of the present application;

fig. 4 is a flowchart of a parking path planning method for a split vehicle according to another embodiment of the present application;

FIG. 5 is a schematic view of a maximum allowable articulation angle;

FIG. 6 is a schematic view of a trailer heading;

FIG. 7 is a schematic view of a course of an initial point to be measured generated according to a deflection angle of a front wheel of a head vehicle;

FIG. 8 is a schematic view of a vehicle course of a target point to be measured;

fig. 9 is a schematic structural diagram of a parking path planning device for a split vehicle according to an embodiment of the present application;

fig. 10 is a schematic structural diagram of a parking path planning apparatus for a split vehicle according to an embodiment of the present application.

Reference numerals: 1. turning on a head; 2. a trailer; 91. a location determination module; 92. a path generation module; 93. an angle calculation module; 94. a path determination module.

Detailed Description

Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated.

The terms referred to in this application are explained first:

the course angle refers to an included angle between the speed of the mass center of the vehicle and a horizontal axis under a ground coordinate system.

The parking path planning method for the split vehicle can be applied to the scenes of ports, high speed, logistics, mines, ports, closed parks, urban traffic and the like, and can be applied to the parking path planning method for the split vehicle as long as the scene of autonomous parking of the split vehicle is related.

When an autonomous vehicle parks autonomously, the autonomous vehicle first stops at a starting point for parking and selects an autonomous parking function on the vehicle. Then, a parking path planning device of the automatic driving vehicle acquires a starting point and a stopping point of parking, and generates a parking path between the starting point and the stopping point by using a reeds-shepp curve in the Hybrid A Star algorithm model. And then, the parking path planning device detects the collision of the generated parking path, and if no collision exists, the parking path is output so as to automatically drive the vehicle to park according to the parking path. If the collision exists, the parking path planning device expands a path node of one step around the starting point by the four-wheel vehicle kinematics principle, and generates the parking path between the starting point and the parking point again by taking a point in the expanded node as a new starting point, and the steps are iterated until the parking path without the collision is detected.

However, unlike the compact body of a passenger car, a split vehicle such as a truck is divided into a towing head car and a trailer, which are connected by a towing pin of the head car, so that a certain angle is formed between the head car and the trailer of the vehicle during driving, especially when turning. Fig. 1 is a schematic view of a process of autonomous parking of a split type vehicle. As shown in fig. 1, a path a and a path b represent parking paths according to a plan, 1 represents a head car of the split type vehicle, and 2 represents a trailer of the split type vehicle. Fig. 1 (1) shows a state where the vehicle is at a starting point; (2) representing a state in which the vehicle travels to an intersection of the route a and the route b according to the route a; (3) indicating a state where the vehicle travels to a stop point according to the path b. As can be seen from (3) in fig. 1, when the split-type vehicle reaches a parking point according to a planned parking path, a large included angle exists between the head car 1 and the trailer 2, and the trailer 2 is not thrown straight. Such a parking state not only does not comply with the parking regulations, but also may create a parking risk.

The application provides a parking path planning method for a split vehicle, and aims to solve the technical problems. According to the method, after the first path between the starting point and the target point is determined by using the RS geometric algorithm, the target parking path in the first path is determined according to the trailer course angle and the articulation angle corresponding to the track point on each path. The path is restrained and limited by the aid of the trailer course angle and the hinge angle, the finally obtained target parking path can be matched with the structure of the split vehicle, the split vehicle can be straightened when reaching the parking position according to the target parking path, parking specifications are met, and the problem that parking hidden danger is generated due to the fact that a large included angle exists between the head vehicle and the trailer is avoided.

The following describes the technical solutions of the present application and how to solve the above technical problems with specific embodiments. The following several specific embodiments may be combined with each other, and details of the same or similar concepts or processes may not be repeated in some embodiments. Embodiments of the present application will be described below with reference to the accompanying drawings.

Fig. 2 is a schematic diagram of an autonomous parking process according to an embodiment of the present application. As shown in fig. 2, a path f, a path j, and a path h represent parking paths planned by a parking path planning device loaded with the parking path planning method for a split type vehicle according to an embodiment of the present application. In fig. 2, 1 denotes a head car of the split type vehicle, and 2 denotes a trailer of the split type vehicle. Fig. 2 (1) shows a state where the vehicle is at a starting point; (2) a state showing that the vehicle travels to the intersection of the route f and the route j according to the route f; (3) representing a state in which the vehicle travels to an intersection of the route j and the route h according to the route j; (4) indicating a state where the vehicle travels to a stop point according to the path h. As can be known from (4) in the figure 2, when the split type vehicle reaches a parking point according to a parking path planned by the parking path planning device, a trailer of the split type vehicle can be straightly thrown, the parking specification is met, and the hidden parking danger caused by a large included angle between a head car and the trailer is avoided.

Example one

Fig. 3 is a flowchart of a parking path planning method for a split vehicle according to an embodiment of the present application, an execution main body of the parking path planning method for the split vehicle according to the embodiment of the present application may be a parking path planning device, or a split vehicle (for short, a split vehicle) integrated with the parking path planning device, and the execution main body is the split vehicle in this embodiment to describe the parking path planning method for the split vehicle. In this embodiment, the split-type vehicle includes a trailer and a head vehicle for driving the trailer. As shown in fig. 3, the parking path planning method for the split vehicle may include the steps of:

s101: and determining a starting point and a target point of split vehicle parking on a pre-established parking scene coordinate system.

In the present embodiment, the parking scene coordinate system is used to determine the start point and the target point of the parking path. The starting point of the parking path can be determined according to the current position automatically positioned by the GPS positioning module in the split vehicle, namely the starting point of the parking path is the current position point of the target vehicle. The target point of the parking path can be determined according to the target position to be reached by the split type vehicle, namely the target point of the parking path is the position point of the target parking space of the split type vehicle.

Of course, in order to determine the starting point and the target point of the parking path more accurately, in this embodiment, the connecting position point of the head car and the trailer corresponding to the current position point of the split type vehicle may be used as the starting point, and the geometric center point of the position point of the target parking space to be reached by the target vehicle may be used as the target point.

In the actual operation process, the target point can also be determined in other manners. For example, the user may manually click on the determined coordinate point directly on the parking scene coordinate system, and use the coordinate point as the coordinates of the target point.

S102: a first path between the starting point and the target point is determined.

In the embodiment, after the starting point and the target point of the split-type vehicle parking are determined, a possible first path between the starting point and the target point can be generated by using an RS geometric algorithm in a Hybrid a Star algorithm model, namely a streams-shepp curve.

The RS geometric algorithm refers to a route planning method based on the geometric algorithm in a Hybrid A Star algorithm model, and can quickly plan a path from a starting point to a terminating point (namely a target point), which is also called a streams-shepp curve.

A reeds-shepp curve generally consists of two arcs, which are part of a circle generated with a certain radius around a starting point and a target point, respectively, and a straight line connecting the two arcs to generate a connecting line, i.e., a first path, between the starting point and the target point. The direction of the two arcs may be determined by the steering of the vehicle, and the radius of the circle in which the two arcs lie may be determined by the minimum turning radius, gear position, etc. of the vehicle. After all possible combinations of the two arcs and a straight line are randomly combined, 48 curves can be generated, which are all possible paths from the starting point to the target point. The 48 curves may then be traversed to find the target parking path therefrom based on predefined conditions.

In this embodiment, the first path between the starting point and the target point may be determined by using an RS geometric algorithm in the prior art, which is not described herein again.

S103: and calculating the trailer course angle and the articulation angle corresponding to each track point on the first path according to the head vehicle course angle of the starting point and the trailer course angle, wherein the articulation angle is the difference between the trailer course angle and the head vehicle course angle.

In this embodiment, the heading angle of the head vehicle can be regarded as the heading angle of the split vehicle, which represents the driving direction of the vehicle, and the heading angle of the trailer represents the driving direction of the trailer. Because the head car of the vehicle is connected with the trailer through the towing pin of the head car, namely the head car is hinged with the trailer, the driving directions, namely the heading angles of the head car and the trailer are slightly different in the driving process of the vehicle, and particularly the difference is large when the vehicle turns. In order to straighten the trailer when the vehicle reaches a target point, the heading angle of the vehicle at the position point is required to be consistent with or have a small difference with the heading angle of the trailer, namely the articulation angle between the vehicle at the position point and the trailer is small. Therefore, after the path is generated, the trailer heading angle and the articulation angle corresponding to each track point in the path need to be calculated, so that a target path meeting the defined condition is selected according to the trailer heading angle and the articulation angle.

In a possible embodiment, the calculating the trailer heading angle and the articulation angle corresponding to each track point on the first path according to the head vehicle heading angle and the trailer heading angle of the starting point in the step S103 may include: determining a head vehicle heading angle corresponding to each track point according to an included angle between the tangential direction of each track point on the first path and the horizontal axis; determining the trailer course angle corresponding to each track point according to the preset step length, the trailer wheelbase, the head vehicle course angle corresponding to each track point, the head vehicle course angle of the starting point and the trailer course angle; and determining the articulation angle corresponding to each track point according to the difference between the head vehicle course angle and the trailer course angle corresponding to each track point.

In one specific embodiment, the following equations (1) and (2) can be used to calculate the trailer heading angle and articulation angle corresponding to each trajectory point on each first path:

wherein alpha is _n Representing the course angle of the trailer corresponding to the nth track point, deltas representing a preset step length, beta _n Representing a head vehicle heading angle corresponding to the nth track point, wherein the head vehicle heading angle corresponding to the nth track point is an included angle between the tangential direction of the nth track point and the horizontal axis; when n-1 is 0, beta _n-1 Heading angle, alpha, of the head vehicle representing a starting point _n-1 A trailer course angle representing a starting point; gamma ray _n Representing the articulation angle corresponding to the nth track point; l denotes the trailer wheelbase.

In this embodiment, when the first path, that is, the curve is known, the tangent line of each track point on the first path can be obtained, so that the included angle between each tangent line of the track point and the horizontal axis of the coordinate system, that is, the heading angle of the head car corresponding to each track point can be obtained. After establishing the parking scene coordinate system and determining the starting point, the head vehicle heading angle of the starting point and the trailer heading angle can be obtained therewith, and can be considered to be known. Under the condition that the preset step length, the wheelbase of the trailer, the head vehicle heading angle of the starting point, the trailer heading angle and the head vehicle heading angle corresponding to each track point are known, the trailer heading angle corresponding to each track point can be simply and accurately calculated according to the formula (1). Under the condition that the heading angle of the head vehicle and the heading angle of the trailer corresponding to each track point are known, the articulation angle corresponding to each track point can be simply and accurately calculated according to the formula (2).

In this embodiment, a person skilled in the art can flexibly set the preset step length according to actual situations, for example, the preset step length may be 0.5m or 0.6m, and is not limited herein.

S104: and determining a target parking path of the split vehicle according to the trailer course angle and the articulation angle.

In this embodiment, please refer to the second embodiment for a specific implementation manner of determining the target parking path of the split vehicle according to the trailer course angle and the articulation angle.

In this embodiment, after the trailer heading angle and the articulation angle corresponding to each trajectory point on each first path are obtained through calculation in step S103, the target parking path of the split vehicle may be determined according to the preset trailer heading angle constraint and the preset articulation angle constraint, so that the split vehicle may straighten the trailer after reaching the target point according to the target parking path.

In this embodiment, after the first path between the starting point and the target point is determined, the target parking path in the first path may be determined according to the trailer heading angle and the articulation angle corresponding to the trajectory point on each path. The path is restrained and limited by the aid of the trailer course angle and the hinge angle, the finally obtained target parking path can be matched with the structure of the split vehicle, the split vehicle can be straightened when reaching a parking position according to the target parking path, parking specifications are met, and the problem that parking hidden danger is caused due to the fact that a large included angle exists between a head vehicle and the trailer is avoided.

The following describes in detail a specific implementation of the embodiment two to the step S104 of the first embodiment in the above embodiments, which determines the target parking path of the split vehicle according to the trailer heading angle and the articulation angle.

Example two

Fig. 4 is a flowchart of a parking path planning method for a split-type vehicle according to an embodiment of the present application, where an execution main body of the parking path planning method for the split-type vehicle according to the embodiment of the present application may be a parking path planning device or a split-type vehicle integrated with the parking path planning device, and the execution main body is used as the split-type vehicle integrated with the parking path planning device (for short, the split-type vehicle) in the embodiment to describe the parking path planning method for the split-type vehicle. In this embodiment, the split-type vehicle includes a trailer capable of accommodating articles and a head car for driving the trailer. As shown in fig. 4, the parking path planning method for the split vehicle may include the steps of:

s201: and sequencing the first paths according to the sequence of the lengths from small to large to generate a first path sequence.

In this embodiment, after the first paths between the starting point and the target point are determined, the first paths may be sorted according to the sequence from the small length to the large length, so that the first paths are traversed according to the sequence from the small length to the large length, and a target parking path satisfying the preset trailer course angle constraint and the preset articulation angle constraint in the first paths is obtained.

In this embodiment, the smaller the loss value of the first path, so that the first path may be traversed according to the sequence of the smaller length to the larger length, so that the target parking path that meets the preset constraint condition obtained by traversal has the smallest loss value.

S202: and sequentially judging whether a second path with the hinge angle smaller than the hinge angle threshold value corresponding to each track point exists in the first path sequence.

S203: and if so, determining the target parking path of the split vehicle according to the trailer course angle.

In this embodiment, if it is found during traversal that the articulation angle corresponding to each track point of a certain first path is smaller than the articulation angle threshold, the path meets the preset articulation angle constraint, and the path may be used as a second path to determine the subsequent constraint condition. If the articulation angles corresponding to the track points of a certain first path are smaller than the articulation angle threshold value during traversal, the path meets the preset articulation angle constraint, and the path is used as a second path to judge the subsequent constraint conditions. If the articulation angle corresponding to the track point in a certain first path is not smaller than the articulation angle threshold value during traversal, the path is not considered, and traversal of the remaining first path sequence is continued.

In one possible embodiment, the step S203 of determining the target parking path of the split vehicle according to the trailer heading angle may include:

s2031: and judging whether the corresponding trailer course angles of all the track points on the second path are smaller than a course angle threshold value.

S2032: and if so, performing collision detection on the second path to determine a target parking path of the split vehicle.

If not, the above step S202 is continued.

In this embodiment, after the second path in which the articulation angles corresponding to the track points are all smaller than the articulation angle threshold is obtained, it may be continuously determined whether the trailer heading angles corresponding to the track points on the second path are all smaller than the heading angle threshold, that is, whether the predetermined trailer heading angle constraint is satisfied. If the constraint condition is met, collision detection can be carried out on the second path, and whether the second path is the target parking path of the split vehicle or not is determined according to the collision detection result. If the constraint condition is not satisfied, the second path is not considered, and the step S202 may be continuously performed to re-traverse to obtain a new second path.

In the embodiment, the trailer course angle of the target parking path is constrained by judging whether the trailer course angle corresponding to each track point on the second path is smaller than the course angle threshold value, namely whether the preset trailer course angle constraint is met, so that the finally obtained target parking path can meet the preset trailer course angle constraint. The trailer course angle when the split type vehicle is positioned at the target point can be limited within a certain range by limiting the trailer course angle, so that the trailer can be straightly thrown.

In this embodiment, the person skilled in the art can flexibly set the articulation angle threshold and the heading angle threshold. It should be noted that the articulation angle threshold and the heading angle threshold are only one angle value, independent of direction. For example, if the articulation angle threshold is 30 °, then both an articulation angle of less than 30 ° for left deflection and an articulation angle of less than 30 ° for right deflection are less than the articulation angle threshold.

In one possible embodiment, the performing collision detection on the second path in step S2032 to determine the target parking path of the split type vehicle may include: determining position information of an obstacle with a distance to the second path smaller than a preset distance; determining whether the split type vehicle collides with the obstacle according to the position information of the obstacle and the geometric shape of the split type vehicle; if yes, continue to execute the above step S202; and if not, determining the target parking path of the split type vehicle according to the second path.

In the actual operation process, the geometric shape of the split type vehicle can be projected onto each track point of the second path, and whether the split type vehicle collides with the obstacle or not is determined according to the coordinate points of the obstacle.

In the present embodiment, a person skilled in the art can flexibly set the preset distance according to the actual size of the split vehicle, for example, the preset distance may be 1m or 1.5m, and is not limited herein.

S204: if not, determining a target point to be measured of the starting point according to the preset step length and the loss value, and re-executing the step of determining the first path between the starting point and the target point by taking the target point to be measured as a new starting point, namely the step S102 in the first embodiment, until determining the target parking path of the split vehicle.

In this embodiment, if no path meeting the preset constraint condition and the collision detection is found through traversing all the first paths, it is indicated that all the paths from the starting point to the target point are not suitable, and the first path needs to be re-determined by taking other position points as new starting points, and the iteration is performed until the target parking path meeting the preset constraint condition and the collision detection is obtained.

In a possible embodiment, the determining the target point to be measured of the starting point according to the preset step length and the loss value in step S204 may include:

s2041: and determining initial points to be measured of the starting point according to the preset step length and the deflection angles of the front wheels of the head vehicle, wherein the deflection angles of the front wheels of the head vehicle are multiple.

S2042: and acquiring state information of the split type vehicle at each initial point to be measured, wherein the state information comprises the length of a path which the split type vehicle has traveled, the steering angle amplitude and the steering angle increment of a steering wheel of the split type vehicle, the switching frequency of gears of the split type vehicle, the distance between the gears and a target point, an articulation angle and steering of the steering wheel.

S2043: determining a sub-loss value corresponding to the state information of each initial point to be measured according to a preset corresponding relation between the state information and the sub-loss value;

s2044: and summing the sub-loss values corresponding to each initial point to be measured to determine the loss value of each initial point to be measured.

S2045: and determining a target point to be measured according to the initial point to be measured with the minimum loss value.

In the present embodiment, the head vehicle front wheel slip angle refers to an angle between an axle of the head vehicle front wheel and an axle of the head vehicle, that is, an angle at which the head vehicle is about to turn. The loss value refers to the cost required for reaching the target point with the corresponding position point as the starting point, and the lower the loss value, the lower the cost consumed.

In this embodiment, different sub-loss values may be set in advance according to each piece of state information, and after the state information of each initial point to be measured is obtained, the sub-loss value corresponding to the state information may be found. For example, different sub-loss values can be set according to the length of the path traveled by different split-type vehicles, and the larger the length is, the larger the corresponding sub-loss value is. Different sub-loss values can be set according to the steering angle amplitudes of different split type vehicle steering wheels, and the larger the amplitude is, the larger the corresponding sub-loss value is. Different sub-loss values can be set by different steering angle amplitude increments, and the larger the increment is, the larger the corresponding sub-loss value is. Different sub-loss values can be set for the switching frequency of different split vehicle gears, and the higher the switching frequency of the forward gear and the backward gear is, the larger the corresponding sub-loss value is. Different distances from the target point can be set to different sub-loss values, and the larger the distance is, the larger the corresponding sub-loss value is. Different sub-loss values can be set for different articulation angles, the larger the articulation angle is, the larger the corresponding sub-loss value is, and when the articulation angle is larger than the articulation angle threshold, the sub-loss value can be set to infinity. The sub-loss value may be set to 0 when the steering wheel steering is consistent with the trailer heading and may be set to infinity when the steering wheel steering is inconsistent with the trailer heading.

During actual driving, the articulation angle cannot be too large, which can damage the mechanical structure of the trailer and possibly exceed the range of the respective angle detection sensor. Fig. 5 is a schematic diagram of the maximum allowable articulation angle, and as shown in fig. 5, if the articulation angle exceeds the maximum allowable articulation angle α (i.e., the articulation angle threshold), the corresponding sub-loss value is set to infinity, so that the search speed of the target point to be measured is increased while the driving safety is ensured. In addition, fig. 6 is a schematic diagram of the trailer course, as shown in fig. 6, at this time, the trailer course is swung to the right, if the steering wheel is turned to the left and the vehicle is backed, the articulation angle will be rapidly increased, such an operation is not in accordance with the driving habit, which belongs to an incorrect driving trend, the corresponding sub-loss value is set to infinity, which can avoid the result that the search is impossible, and improve the overall search speed.

In a possible embodiment, the determining the initial point to be measured of the starting point according to the preset step length and the front wheel slip angle in step S2041 may include: determining the abscissa of the initial point to be measured according to the preset step length, the abscissa of the starting point and the heading angle of the head vehicle of the starting point; determining a vertical coordinate of an initial point to be measured according to a preset step length, a vertical coordinate of the initial point and a head vehicle course angle of the initial point; determining a head vehicle course angle of an initial point to be measured according to a preset step length, a head vehicle course angle of the initial point, a head vehicle wheel base and a head vehicle front wheel deflection angle; and determining the trailer course angle of the initial point to be measured according to the preset step length, the head vehicle course angle of the initial point, the trailer course angle of the initial point and the trailer wheelbase.

In one specific embodiment, the position coordinates of the initial point to be measured around the starting point, the head vehicle heading angle, and the trailer heading angle may be calculated using the following equations (3) to (6):

wherein x is _t-1 Abscissa, x, representing the starting point _t Abscissa, y, representing the initial point to be measured _t-1 Ordinate, y, representing a starting point _t Representing the vertical coordinate of the initial point to be measured; theta _0，t-1 Representing a head vehicle course angle of the starting point, and delta s represents a preset step length; theta _0，t Representing a head vehicle course angle of an initial point to be measured, l representing a head vehicle wheel base, and delta representing a head vehicle front wheel deflection angle; theta _1，t-1 Trailer course angle, θ, representing a starting point _1，t The course angle of the trailer of the initial point to be measured is shown, and L represents the wheelbase of the trailer.

In this embodiment, since determining the position coordinates of the initial points to be measured is a virtual approximate process, the position coordinates of the initial points to be measured can be regarded as the same, and only the corresponding heading angles are different. Fig. 7 is a schematic view of the heading of the initial point to be measured generated according to the deflection angle of the front wheel of the head vehicle, as shown in fig. 7, a white dot in fig. 7 represents the initial point to be measured, and a black dot represents the starting point. The position of each white dot in fig. 7 represents only its heading and does not represent the actual position coordinates. In fig. 7, the included angle between the horizontal axis and the curve between each white point and each black point represents the front wheel deflection angle of the head car, and the corresponding heading angle of the head car can be obtained according to the formula (5) and the front wheel deflection angle of the head car.

FIG. 8 is a schematic view of the vehicle heading of a target point to be measured, as shown in FIG. 8, where 1 in FIG. 8 represents a head vehicle, 2 represents a trailer, and θ represents ₀ Representing a head vehicle course angle of a target point to be measured, and delta representing a head vehicle front wheel deflection angle; theta ₁ And the course angle of the trailer representing a target point to be measured, the wheelbase of the head vehicle is represented by L, and the wheelbase of the trailer is represented by L.

In this embodiment, if a target parking path still cannot be obtained according to the series of corresponding target points to be measured as a starting point, iteration may be continuously performed according to the above equations (3) - (6) to generate new target points to be measured until a target parking path satisfying the preset constraint condition and collision detection is obtained.

In the embodiment, after the position coordinates, the head vehicle heading angle and the trailer heading angle are calculated according to the formulas (3) to (6), the initial point to be measured of the starting point can be simply and accurately determined according to the preset step length and the head vehicle front wheel deflection angle.

In this embodiment, after determining and sorting the first path between the start point and the target point, it may be first determined whether there is a second path in the first path sequence where the articulation angle corresponding to each trajectory point is smaller than the articulation angle threshold, that is, whether the articulation angle constraint is satisfied. If so, whether the trailer course angles corresponding to the track points on the second path are all smaller than the course angle threshold value or not can be continuously judged, namely whether the trailer course angle constraint is met or not can be continuously judged. If the constraint of the trailer course angle is met, collision detection can be continuously carried out on the second path, and if no collision exists between the second path and the obstacle, the second path is the target parking path. Through the arrangement, the finally obtained target parking path can meet the preset constraint condition and the collision detection.

The parking path planning method for the split-type vehicle according to the present application is described below with a specific embodiment.

EXAMPLE III

In a specific embodiment, a driver sets the autonomous driven truck to travel to a parking lot, and the driver selects the autonomous parking function on the vehicle to want to reach the parking lot by autonomous parking. Firstly, a parking path planning device on a truck plans a parking path for the truck, and the specific parking path planning process is as follows:

firstly, the parking path planning device determines a starting point of split vehicle parking according to the GPS positioning module on a pre-established parking scene coordinate system, and prompts a driver to select a target position, and the driver determines a target point corresponding to the target position on the coordinate system after selecting the target position.

In the second step, the parking path planning device determines 48 first paths between the starting point and the target point by using an RS geometric algorithm.

And thirdly, the parking path planning device calculates the trailer course angle and the articulation angle corresponding to each track point on each first path by using the formulas (1) and (2) in the first embodiment.

And fourthly, sequencing the first paths according to the sequence of the lengths from small to large to generate a first path sequence.

And fifthly, sequentially judging whether a second path with the hinge angle smaller than the hinge angle threshold value corresponding to each track point exists in the first path sequence.

And sixthly, judging that a second path exists in the first path sequence, wherein the articulation angles corresponding to the track points are all smaller than the articulation angle threshold.

And seventhly, judging whether the course angles of the trailers corresponding to the track points on the second path are all smaller than a course angle threshold value.

And eighthly, if so, determining the position information of the obstacle with the distance to the second path smaller than the preset distance.

And ninthly, determining whether the split type vehicle collides with the obstacle or not according to the position information of the obstacle and the geometric shape of the split type vehicle, and if not, determining that the second path is the target parking path.

After the target parking path of the truck is determined, the parking path planning device sends the target parking path to a control unit of the truck, and the control unit controls the truck to drive from a starting point to a parking space corresponding to a target point, so that autonomous parking is completed.

Fig. 9 is a schematic structural diagram of a parking path planning device for a split type vehicle according to an embodiment of the present application, and as shown in fig. 9, the parking path planning device for the split type vehicle includes: a position determination module 91, a path generation module 92, an angle calculation module 93, and a path determination module 94. The position determining module 91 is configured to determine a starting point and a target point of split vehicle parking on a parking scene coordinate system established in advance. The path generation module 92 is configured to determine a first path between the start point and the target point. The angle calculation module 93 is configured to calculate a trailer heading angle and an articulation angle corresponding to each track point on the first path according to the head vehicle heading angle of the start point and the trailer heading angle, where the articulation angle is a difference between the trailer heading angle and the head vehicle heading angle. The path determination module 94 is configured to determine a target parking path for the split vehicle based on the trailer heading angle and the articulation angle. In an embodiment, the description of the specific implementation functions of the parking path planning device for a split-type vehicle may refer to steps S101 to S104 in the first embodiment, which are not described herein again.

Fig. 10 is a schematic structural diagram of a parking path planning apparatus for a split type vehicle according to an embodiment of the present application, and as shown in fig. 10, the parking path planning apparatus for a split type vehicle includes: a processor 101, and a memory 102 communicatively coupled to the processor 101; the memory 102 stores computer-executable instructions; the processor 101 executes computer-executable instructions stored in the memory 102 to implement the steps of the parking path planning method for the split type vehicle in the above embodiments of the method.

The parking path planning device of the split type vehicle can be independent or part of the split type vehicle, and the processor 101 and the memory 102 can adopt the existing hardware of the split type vehicle.

In the parking path planning apparatus for a split vehicle, the memory 102 and the processor 101 are electrically connected directly or indirectly to realize data transmission or interaction. For example, the components may be electrically connected to each other via one or more communication buses or signal lines, such as a bus. The memory 102 stores computer-executable instructions for implementing the data access control method, including at least one software functional module that can be stored in the memory 102 in the form of software or firmware, and the processor 101 executes various functional applications and data processing by running software programs and modules stored in the memory 102.

The Memory 102 may be, but is not limited to, a Random Access Memory (RAM), a Read Only Memory (ROM), a Programmable Read-Only Memory (PROM), an Erasable Read-Only Memory (EPROM), an electrically Erasable Read-Only Memory (EEPROM), and the like. The memory 102 is used for storing programs, and the processor 101 executes the programs after receiving the execution instructions. Further, the software programs and modules within the memory 102 may also include an operating system, which may include various software components and/or drivers for managing system tasks (e.g., memory management, storage device control, power management, etc.), and may communicate with various hardware or software components to provide an operating environment for other software components.

The processor 101 may be an integrated circuit chip having signal processing capabilities. The Processor 101 may be a general-purpose Processor, and includes a Central Processing Unit (CPU), a Network Processor (NP), and so on. The various methods, steps, and logic blocks disclosed in the embodiments of the present application may be implemented or performed. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.

An embodiment of the present application further provides a computer-readable storage medium, in which computer-executable instructions are stored, and the computer-executable instructions are executed by a processor to implement the steps of the method embodiments of the present application.

An embodiment of the present application also provides a computer program product comprising a computer program that, when being executed by a processor, performs the steps of the method embodiments of the present application.

Other embodiments of the present application will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the application and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the application being indicated by the following claims.

It will be understood that the present application is not limited to the precise arrangements described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof.

Claims

1. A parking path planning method for a split vehicle, wherein the split vehicle comprises a trailer and a head vehicle driving the trailer to run, is characterized by comprising the following steps:

determining a first path between the starting point and the target point;

2. The method according to claim 1, wherein the determining the target parking path of the split vehicle according to the trailer heading angle and the articulation angle specifically comprises:

3. The method according to claim 2, wherein the determining the target parking path of the split vehicle according to the trailer heading angle specifically comprises:

4. The method according to claim 3, wherein the performing collision detection on the second path to determine the target parking path of the split vehicle specifically comprises:

5. The method according to any one of claims 2 to 4, wherein the determining the target point to be measured of the starting point according to the preset step length and the loss value specifically comprises:

6. The method according to claim 5, wherein the determining the initial point to be measured of the starting point according to the preset step length and the front wheel slip angle of the head specifically comprises:

7. The method according to claim 6, wherein the calculating of the trailer heading angle and the articulation angle corresponding to each trajectory point on the first path according to the head vehicle heading angle and the trailer heading angle of the start point comprises:

8. A parking path planning apparatus for a split vehicle, comprising:

9. A parking path planning device of a split vehicle comprises a processor and a memory which is connected with the processor in a communication way;

the memory stores computer-executable instructions;

the processor executes computer-executable instructions stored by the memory to implement the method of any of claims 1 to 7.

10. A computer-readable storage medium having computer-executable instructions stored therein, which when executed by a processor, are configured to implement the method of any one of claims 1 to 7.