Parking path processing method, device, electronic device and storage medium

Abstract

The present application relates to a parking path processing method, apparatus, electronic device, and storage medium. The method comprises: obtaining an initial parking path for a vehicle and determining circular arcs within the initial parking path; processing each circular arc into a combination of a first clothoid curve, a target circular arc, and a second clothoid curve, wherein the first endpoint of the first clothoid curve is the first endpoint of the circular arc curve, and the instantaneous radius of the first clothoid curve at the second endpoint is equal to the radius of the target circular arc; the first clothoid curve and the second clothoid curve are symmetrical about a line connecting the midpoint of the target circular arc and the center of the circle containing the target circular arc; and determining a final parking path based on the combination of the first clothoid curve, the target circular arc, and the second clothoid curve and a straight portion within the initial parking path. This improves control accuracy, effectively prevents tire steering, and reduces tire wear during parking.

Description

Technical Field

[0001] The present application relates to the technical field of automatic parking, and in particular to a parking path processing method, device, electronic device and storage medium. Background Art

[0002] Automatic parking is an integral part of autonomous driving, and parking path planning plays a crucial role. Parking path planning methods generally fall into two categories: geometric methods and search methods.

[0003] Among them, the geometric method uses a combination of straight lines and arcs to obtain the parking path. This method is simple and efficient, and the project implementation is relatively easy. However, this type of method has a sudden change in curvature at the arc-straight line or arc-arc joints, resulting in poor control effect and the possibility of tire turning on the spot. Summary of the Invention

[0004] The present application provides a parking path processing method, device, electronic device and storage medium, which can improve control accuracy, effectively avoid tire turning on the spot, and reduce tire wear during parking.

[0005] In a first aspect, the present application provides a parking path processing method, comprising:

[0006] Obtaining an initial parking path of the vehicle and determining an arc curve in the initial parking path;

[0007] Each circular arc curve is processed into a combination of a first clothoid curve, a target circular arc, and a second clothoid curve, wherein the first endpoint of the first clothoid curve is the first endpoint of the circular arc curve, and the instantaneous radius of the first clothoid curve at the second endpoint is equal to the radius of the target circular arc; the first clothoid curve and the second clothoid curve are symmetrical based on the line connecting the midpoint of the target circular arc and the center of the circle in which the target circular arc is located;

[0008] A final parking path is determined according to a combination of the first clothoid curve, the target circular arc, and the second clothoid curve and a straight line portion in the initial parking path.

[0009] In a second aspect, an embodiment of the present application provides a parking path processing device, comprising:

[0010] a circular arc curve determination module, configured to obtain an initial parking path of the vehicle and determine a circular arc curve in the initial parking path;

[0011] an arc curve processing module, configured to process each arc curve into a combination of a first clothoid curve, a target arc, and a second clothoid curve, wherein the first endpoint of the first clothoid curve is the first endpoint of the arc curve, and the instantaneous radius of the first clothoid curve at the second endpoint is equal to the radius of the target arc; and the first clothoid curve and the second clothoid curve are symmetrical about a line connecting the midpoint of the target arc and the center of the circle in which the target arc is located;

[0012] The final parking path determining module is configured to determine a final parking path according to a combination of the first clothoid curve, the target circular arc, and the second clothoid curve and a straight line portion in the initial parking path.

[0013] In a third aspect, an embodiment of the present application provides an electronic device, including:

[0014] memory for storing computer programs;

[0015] The processor is used to execute the computer program stored in the memory, and when the computer program is executed, the method provided in the embodiment of the present application is implemented.

[0016] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the method provided in the embodiment of the present application is implemented.

[0017] The above-mentioned technical solution provided by the embodiment of the present application has the following advantages over the prior art: the method provided by the embodiment of the present application can process each circular arc curve in the initial parking path into a combination of a first clothoid curve-a target circular arc-a second clothoid curve, so that each circular arc curve can be processed into a curve with continuous curvature. Specifically, by setting the first endpoint of the first clothoid curve as the first endpoint of the circular arc curve, and making the instantaneous radius of the first clothoid curve at the second endpoint equal to the radius of the target circular arc, the first clothoid curve and the target circular arc can maintain curvature continuity at the second endpoint of the first clothoid curve. The curvature continuity can be maintained at the connection point of the target circular arc and the second clothoid curve through the second clothoid curve symmetrical to the first clothoid curve, ensuring that the combination of the first clothoid curve-target circular arc-second clothoid curve processed by each circular arc maintains curvature continuity, thereby converting the parking path into a path with continuous curvature, improving control accuracy, effectively avoiding tire turning in place, and reducing tire wear during parking. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0019] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0020] One or more embodiments are exemplarily illustrated by pictures in the corresponding drawings. These exemplifications do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings are represented as similar elements. Unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0021] Figure 1 It is a schematic diagram of a parking scenario;

[0022] Figure 2 is a graph showing the relationship between path curvature k and path length s before the initial parking path is processed;

[0023] Figure 3 It is a schematic diagram of a clothoid;

[0024] Figure 4 This is a flow chart of a parking path processing method provided by an embodiment of the present application;

[0025] Figure 5 The final parking path is obtained after processing, and a parking scene diagram based on the final parking path is provided;

[0026] Figure 6 is a graph showing the relationship between the path curvature k and the path length s after the initial parking path is processed;

[0027] Figure 7 This is a flow chart of a method for processing each circular arc curve into a combination of a first clothoid curve, a target circular arc, and a second clothoid curve, provided in an embodiment of the present application;

[0028] Figure 8 It is a schematic diagram of the arc curve processing process in the initial parking path;

[0029] Figure 9 1 is a flowchart of a method provided in an embodiment of the present application for performing a symmetric operation on a target curve based on a line connecting the midpoint of the target arc to the target intersection point to obtain a combination of a first clothoid curve, a target arc, and a second clothoid curve;

[0030] Figure 10 A flow chart for processing circular curves in an initial parking path;

[0031] Figure 11 This is a structural block diagram of a parking path processing device provided in an embodiment of the present application;

[0032] Figure 12 This is a structural block diagram of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0033] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0034] The disclosure below provides many different embodiments or examples for implementing different structures of the present application. In order to simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, these are merely examples and are not intended to limit the present application. In addition, the present application may repeat reference numbers and / or letters in different examples. Such repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or settings discussed.

[0035] Figure 1 This is a schematic diagram of a parking scenario. Taking this scenario as an example, other scenarios are similar. First, the parking path is planned using the geometric planning method, such as Figure 1 As shown, the vehicle starts from point A, moves forward along the straight line AB to point B, turns left with a fixed turning radius along the arc curve BC to point C, changes gears at point C, and then reverses along the circular curve CD with a fixed turning radius to point D, and finally reverses along the straight line DE to point E to complete parking.

[0036] The above parking path is composed of a straight line , arc curve BC, arc curve CD and straight line DE, with the connection points B, C and D. At the connection points of these three points, the curvature is 、 、 The curve of path curvature k and path length s is as follows: Figure 2 Among them, in the above parking path, the curvature of the connection between the arc curve and the straight line, and between the arcs, changes suddenly, which can easily lead to poor control effect and the situation where the tires turn on the spot.

[0037] In order to solve the technical problems of poor control effect caused by sudden change of curvature in the parking path in the prior art and the tire turning in place, the present application provides a parking path processing method, device, electronic device and storage medium, which uses a clothoid to process the arc curve in the parking path, and can transform the parking path into a path with continuous curvature, thereby improving the control accuracy, effectively avoiding tire turning in place, and reducing tire wear during parking. Figure 3 The solid line starts at O0, has a curvature of 0, and extends to point At this point, the vehicle reaches its minimum turning radius , the instantaneous center is , at this time, the length of the path traveled is The formula of the clothoid curve is:

[0038]

[0039] in, L is the arc length, R The arc length is L The turning radius at A Characterizes the curvature characteristics of the clothoid curve.

[0040] Figure 4 This is a flow chart of a parking path processing method provided by an embodiment of the present application. Figure 3 As shown, the method includes the following steps:

[0041] Step 401: Acquire an initial parking path of the vehicle and determine an arc curve in the initial parking path.

[0042] In the technical solution of the embodiment of the present application, the initial parking path may be a parking path planned in the early stage by a geometric algorithm, and the initial parking path includes an arc curve part and a straight line part. Figure 1 As shown, the initial parking path contains a straight line , circular curve BC, circular curve CD and straight line DE.

[0043] In one embodiment, a method for determining the circular arc curve in the initial parking path may be to segment the initial parking path according to geometric connection points, and select the circular arc curve in the segmented initial parking path, for example, Figure 1 As shown, the geometric connection points include points B, C, and D. The initial parking path is divided into four segments: AB, BC, CD, and DE. You can select the circular curves BC and CD for processing, leaving the straight line segments untouched.

[0044] Step 402: Process each circular arc curve into a combination of a first clothoid curve-a target circular arc-a second clothoid curve, wherein the first endpoint of the first clothoid curve is the first endpoint of the circular arc curve, and the instantaneous radius of the first clothoid curve at the second endpoint is equal to the radius of the target circular arc; the first clothoid curve and the second clothoid curve are symmetrical based on the line connecting the midpoint of the target circular arc and the center of the circle where the target circular arc is located.

[0045] The above-mentioned first endpoint can be the starting point and the corresponding second endpoint can be the end point, or the above-mentioned first endpoint can be the end point and the corresponding second endpoint can be the starting point. For the convenience of calculation, the first endpoint can be considered as the starting point and the second endpoint can be considered as the end point.

[0046] Specifically, for each circular arc curve, the first endpoint of the circular arc curve can be used as the first endpoint of the first clothoid curve, and the second endpoint of the second clothoid curve can be continuously explored through the calculation method until the second endpoint of the second clothoid curve is determined. Specifically, the second endpoint of the second clothoid curve can be continuously explored through the comparison relationship between the instantaneous radius of the first clothoid curve at the second endpoint and the radius of the target circular arc, until the instantaneous radius of the first clothoid curve at the second endpoint and the radius of the target circular arc meet the equality condition. In this case, the second endpoint of the first clothoid curve is used as the second endpoint of the first clothoid curve that actually needs to be found. After determining the second endpoint of the first clothoid curve, the first clothoid curve is determined; a calculation method is used to calculate the midpoint of a target arc, and an arc from the second endpoint of the first clothoid curve to the midpoint in the target arc can be used as a first arc; a symmetry operation is performed on a combined curve formed by the first clothoid curve and the first arc based on a line connecting the midpoint of the target arc and the center of the circle in which the target arc lies, thereby obtaining a second arc symmetrical to the first arc, and obtaining a second clothoid curve symmetrical to the first clothoid curve, thereby combining the first clothoid curve, the first arc, the second arc, and the second clothoid curve to obtain a combination of the first clothoid curve, the target arc, and the second clothoid curve. The combination of the first arc and the second arc forms the target arc.

[0047] Step 403 : Determine a final parking path according to a combination of the first clothoid curve, the target arc, and the second clothoid curve and the straight line portion in the initial parking path.

[0048] Specifically, each arc curve corresponds to a combination of a first clothoid curve, a target arc, and a second clothoid curve. In the initial parking path, each arc curve is replaced with the corresponding combination of the first clothoid curve, the target arc, and the second clothoid curve to obtain the final parking path. For example, Figure 5As shown in FIG, after the initial parking path is processed, the final parking path is obtained. The final parking path can be the solid line portion formed by ABCDE, wherein the dotted line portion is the arc curve portion in the initial parking path. By processing the arc curve in the initial parking path, Figure 5 The curvatures of points A, B, C, D, and E in the final parking path are all 0, achieving curvature continuity in the geometric connection points.

[0049] Figure 5 The final parking path shown is the final parking path obtained after processing the initial parking path. The relationship between the path curvature k and the path length s can be referred to Figure 6 ,like Figure 6 As shown in the figure, the solid line part is the path curvature of the initial parking path after processing, and the dotted line part is the path curvature before processing. Figure 2 It can be seen that the path curvature k is continuous with the path length s, and there is no problem of curvature mutation.

[0050] The technical solution provided by the embodiment of the present application can process each circular arc curve in the initial parking path into a combination of a first clothoid curve, a target circular arc, and a second clothoid curve, so that each circular arc curve can be processed into a curve with continuous curvature. Specifically, by setting the first endpoint of the first clothoid curve as the first endpoint of the circular arc curve, and making the instantaneous radius of the first clothoid curve at the second endpoint equal to the radius of the target circular arc, the first clothoid curve and the target circular arc can maintain curvature continuity at the second endpoint of the first clothoid curve. The curvature continuity can be maintained at the connection point of the target circular arc and the second clothoid curve through a second clothoid curve symmetrical to the first clothoid curve, thereby ensuring that the combination of the first clothoid curve, the target circular arc, and the second clothoid curve processed from each circular arc maintains curvature continuity, thereby converting the parking path into a path with continuous curvature, improving control accuracy, effectively avoiding tire turning on the spot, and reducing tire wear during parking.

[0051] In the prior art, most post-processing solutions for parking paths use numerical optimization methods to obtain curvature-continuous parking paths. However, because this method involves solving nonlinear optimal problems, it has low solution efficiency and is difficult to implement in practice. Furthermore, it often requires modeling the nonlinear problem during the front-end initial parking path planning, resulting in poor decoupling between the front-end initial parking path planning and the back-end processing. The technical solution provided in this application provides post-processing of the initial parking path without affecting the front-end initial parking path planning. It can be decoupled from the front-end initial parking path planning algorithm and is adaptable to front-end planning algorithms for any combination of arcs and straight lines. It offers strong compatibility and does not change the endpoint positions of any arc curves in the initial parking path. It can maintain the shift points of the initial parking path planned by the front-end, aligning them with the front-end decision-making process and providing high reliability.

[0052] Figure 7 This is a flow chart of a method for processing each circular arc curve into a combination of a first clothoid curve, a target circular arc, and a second clothoid curve, provided in an embodiment of the present application. Figure 7 The process shown in Figure 4 Based on the process shown, the process includes the following steps:

[0053] Step 701: For each arc curve, determine the center of the circle where the arc curve is located and determine a target straight line passing through the center of the circle where the arc curve is located and the target midpoint, wherein the target midpoint is the midpoint of the line segment formed by the two endpoints of the arc curve.

[0054] As an optional implementation, determining the center of the circle where the arc curve is located includes: determining the center of the circle where the arc curve is located based on the following formula:

[0055] (1)

[0056] in, and are the abscissa and ordinate of the center of the circle where the arc curve lies; 、 and are the abscissa, ordinate and heading angle of the first endpoint of the circular arc curve respectively; 、 and are the horizontal coordinate, vertical coordinate and heading angle of the second endpoint of the arc curve respectively. Figure 8 To illustrate, the center of the circle where the arc curve is located is determined according to the two endpoints of the arc curve, such as Figure 8 As shown, the two endpoints of the arc curve are and ); is the arc curve to be processed, and the arc curve is calculated according to the above formula (1) The center of the circle It should be noted that when calculating the coordinates of the center of the arc curve, in order to facilitate the calculation, the coordinate system can be converted first, and the absolute coordinate system can be converted to the first endpoint of the arc curve. is the coordinate system of the vertex, and then the calculation is performed. Figure 8 As shown, the target midpoint is an arc curve The two endpoints form the midpoint of the line segment, that is, the line segment The midpoint of Point, passing through the arc curve The center of the circle point and target midpoint The target line of the point is a straight line .

[0057] Step 702: Using the first endpoint of the circular arc curve as the first endpoint of the first clothoid curve.

[0058] refer to Figure 8 To explain, such as Figure 8 As shown, the arc curve The first endpoint ( point) as the first endpoint of the first clothoid curve.

[0059] Step 703: The arc length of the first clothoid curve is preset as the current preset arc length, and an initial second endpoint of the first clothoid curve is determined based on the current preset arc length.

[0060] As an optional implementation, determining the initial second endpoint of the first clothoid curve based on the current preset arc length includes: determining the initial second endpoint of the first clothoid curve based on the following formula:

[0061] (2)

[0062] in, 、 and are respectively the abscissa, ordinate and heading angle of the initial second endpoint of the first clothoid curve in a coordinate system with the first endpoint of the circular arc curve as the vertex;

[0063] Where A is the parameter of the first clothoid curve, (3);

[0064] in, is the maximum speed when parking, is the maximum steering wheel angle, is the maximum angular velocity, , is the current preset arc length, is the minimum turning radius.

[0065] refer to Figure 8 To explain, such as Figure 8 As shown, the current preset arc length is The other endpoint of the first clothoid curve is Point, as the initial second endpoint of the first clothoid curve, where, as Figure 8 As shown, the first clothoid curve is Point to The solid line curve of the point. The initial and second endpoints of the first clothoid curve can be calculated by the above formula (2) The coordinates of the point and the heading angle A represents the curvature of the first clothoid curve and can be calculated using the above formula (3).

[0066] Step 704: Determine the intersection point of the normal line passing through the initial second endpoint and the target straight line, and use it as the target intersection point. Determine the length between the target intersection point and the initial second endpoint, and use it as the radius of the target arc.

[0067] refer to Figure 8 To explain, such as Figure 8 As shown, after the initial second endpoint ( point) and the normal of the target line (straight line ) The intersection point is Point, that is, the target intersection point is point, the length between the target intersection point and the initial second endpoint is Point to The length of the point, that is, the line segment The length of the The length of the target arc is actually arrive The arc of the point, at this time The radius of the point (the coordinates of which are unknown) .

[0068] As an optional implementation, determining the intersection point of the normal line passing through the initial second endpoint and the target straight line includes: determining the intersection point of the normal line passing through the initial second endpoint and the target straight line based on the following formula:

[0069] (4)

[0070] in, 、 are the horizontal and vertical coordinates of the target intersection point in the coordinate system with the first endpoint of the arc curve as the vertex;

[0071] in, (5);

[0072] in, is the slope of the target line; 、 are the horizontal and vertical coordinates of the target midpoint in the coordinate system with the first endpoint of the arc curve as the vertex; 、 are the abscissa and ordinate of the center of the circle where the circular curve lies in the coordinate system with the first endpoint of the circular curve as the vertex; 、 are respectively the abscissa, ordinate and heading angle of the initial second endpoint in the coordinate system with the first endpoint of the arc curve as the vertex.

[0073] As an optional implementation, determining the length between the target intersection point and the initial second endpoint includes: determining the length between the target intersection point and the initial second endpoint based on the following formula:

[0074] (6)

[0075] in, is the length between the target intersection point and the initial second endpoint, which serves as the radius of the target arc; 、 are the horizontal and vertical coordinates of the target intersection point in the coordinate system with the first endpoint of the arc curve as the vertex, 、 are respectively the horizontal coordinate and vertical coordinate of the initial second endpoint in the coordinate system with the first endpoint of the arc curve as the vertex.

[0076] Among them, reference Figure 8 , It is a straight line The slope of can be calculated by the above formula (5), that is, by Dot and The coordinates of the point are calculated; after the initial second endpoint ( point) and the target line ( ) The coordinates of can be calculated using the above formula (4), Length The target arc can be calculated by the above formula (6), that is, It should be noted that at this time, the first endpoint of the target arc Point confirmation, the second endpoint of the target arc The point has not been determined yet, so it is introduced here In order to facilitate the expression and understanding, the above formula is not introduced. 's coordinates.

[0077] Step 705: Determine whether the radius of the target arc and the instantaneous radius of the first clothoid curve at the initial second endpoint meet the equality condition.

[0078] In the technical solution of the embodiment of the present application, in step 705, a determination is made as to whether the difference between the radius of the target arc and the instantaneous radius of the first clothoid curve at the initial second endpoint is less than a preset error value. If so, the two are determined to be equal; otherwise, the two are determined not to be equal. The preset threshold can be obtained based on test data from actual vehicle operation.

[0079] In the technical solution of the embodiment of the present application, if it is determined that the radius of the target arc and the instantaneous radius of the first clothoid curve at the initial second endpoint do not meet the equality condition, execute 706; if they meet the equality condition, execute 707.

[0080] In an optional embodiment, whether the radius of the target arc and the instantaneous radius meet the equality condition is determined based on the following formula:

[0081] (7)

[0082] in, is the radius of the target arc, is the preset error value, is the instantaneous radius.

[0083] refer to Figure 8 To explain, such as Figure 8 As shown, in the target arc The radius of the line segment length, ) and the first clothoid curve exist Instantaneous radius at point If the conditions are met, it means that the first clothoid curve Arc with target exist The curvature at the point is continuous, so the target arc needs to be The radius of the first clothoid exist Instantaneous radius at point Whether the equality conditions are met is judged to understand the first clothoid curve Arc with target exist Whether the curvature at the point is continuous.

[0084] Step 706: Change the current preset arc length, use the changed arc length as the current preset arc length, and return to step 703.

[0085] Step 707: Using the last initial second endpoint as the second endpoint of the first clothoid curve.

[0086] As an optional implementation, the current preset arc length can be changed by using the bisection method, and the process returns to step 703, and steps 703-705 are repeated. The last initial second endpoint is used as the second endpoint of the first clothoid curve. The specific method of using the bisection method to change the current preset arc length is to divide the current preset arc length into two parts, and according to the comparison result of the target length and the instantaneous radius, determine whether to select the length of the changed arc length in the first half of the current preset arc length or in the second half. After determining the changed arc length, the process returns to step 703 until the radius of the target arc and the instantaneous radius meet the equality condition. Figure 8 ,like Figure 8 As shown, in the line segment The length of the first clothoid exist Instantaneous radius at point Under the same conditions, the The point is used as the second endpoint of the final first clothoid curve.

[0087] Step 708: Determine the midpoint of the target arc; wherein the center of the circle where the target arc is located is the target intersection point, and the first endpoint of the target arc is the second endpoint of the first clothoid curve.

[0088] As an optional implementation, determining the midpoint of the target arc includes: determining the midpoint of the target arc based on the following formula:

[0089] (8)

[0090] in, is the semi-center angle of the target arc; 、 and are respectively the horizontal coordinate, vertical coordinate and heading angle of the midpoint of the target arc in the coordinate system with the first endpoint of the arc curve as the vertex; is the vector from the target intersection point to the target midpoint, is the vector from the target intersection point to the second endpoint of the first clothoid curve.

[0091] refer to Figure 8 To illustrate, after continuously determining the first clothoid curve The second endpoint of the last obtained Point is the second endpoint of the first clothoid curve, and the target arc The first endpoint is the first clothoid curve The second endpoint of Point, target arc The center of the circle is Point, the radius of the circle is the line segment , Point is the midpoint of the target arc. The target arc is calculated by the above formula (8): The midpoint of yes ; yes , The target arc The semi-central angle of .

[0092] Step 709: Perform a symmetric operation on the target curve based on the line between the midpoint of the target arc and the target intersection point to obtain a combination of the first spiral curve-target arc-second spiral curve; wherein, the target curve is a curve obtained by combining the first spiral curve and the first arc obtained based on the first endpoint of the first spiral curve and the second endpoint of the first spiral curve; the first arc is the arc between the second endpoint of the first spiral curve and the midpoint of the target arc in the target arc.

[0093] refer to Figure 8 To explain, such as Figure 8 As shown, the target curve is the first clothoid curve With the first arc The curve formed , the curve Line segment based By performing symmetry operations, we can obtain the combination of the first clothoid curve, the target arc, and the second clothoid curve, thereby converting the arc curve Convert to curve .

[0094] Figure 9 This is a flow chart of a method provided by an embodiment of the present application for performing a symmetric operation on a target curve based on a line connecting the midpoint of a target arc to a target intersection point to obtain a combination of a first clothoid curve, a target arc, and a second clothoid curve. Figure 9 The process shown in Figure 8 Based on the process shown, the method includes the following steps:

[0095] Step 901: Determine a symmetric point on which the second endpoint of the first clothoid curve is symmetrical to a target symmetry line; wherein the target symmetry line is a line connecting the midpoint of the target circular arc to the target intersection point.

[0096] As an optional implementation manner, determining the second endpoint of the first clothoid curve based on a symmetric point of the target symmetry line includes:

[0097] The symmetry point is determined based on the following formula:

[0098] (9)

[0099] in, and are the horizontal and vertical coordinates of the symmetrical point in the coordinate system with the first endpoint of the arc curve as the vertex. In the above formula (9), 、 and It is an intermediate quantity in the calculation process, refer to Figure 8 , the first clothoid curve The second endpoint Points based on target symmetry line The symmetry point is , the symmetric point can be calculated by the above formula (9) The reason why we need to calculate the symmetry point first in this application is , in order to find the segmentation points of the target arc and the second clothoid curve, so as to make the symmetry operation more efficient.

[0100] Step 902: Determine a second clothoid curve that is symmetrical to the target symmetry line and is a result of the first clothoid curve being determined between the symmetry point and the second endpoint of the arc curve.

[0101] Step 903: Determine a second arc that is symmetrical to the target symmetry line and is located between the midpoint and the symmetry point of the target arc.

[0102] Step 904 : The first clothoid curve, the first circular arc, the second circular arc, and the second clothoid curve form a combination of the first clothoid curve-the target circular arc-the second clothoid curve.

[0103] Steps 902-904 are described in a unified manner. In step 902, discrete points are selected on the first clothoid curve, and these discrete points are symmetrically connected based on the target symmetry line to find corresponding symmetrical points. The symmetrical points of the second endpoint of the first clothoid curve, the symmetrical points corresponding to these discrete points, and the second endpoint of the arc curve are connected in sequence to obtain the second clothoid curve. Figure 8 , in the first clothoid curve Select discrete points and base them on line segments Perform symmetry and obtain a series of corresponding symmetric points. points, a series of symmetrical points corresponding to these discrete points, and Connect the points in order to get the second clothoid curve .

[0104] In step 903, discrete points are selected on the first arc, these discrete points are symmetrically arranged based on the target symmetrical point, corresponding symmetrical points are found, and the midpoint of the target arc, the symmetrical points corresponding to these discrete points, and the symmetrical point of the second end point of the first clothoid curve are connected in sequence to obtain a second arc. Figure 8 , in the first arc Select discrete points and base them on line segments Perform symmetry to obtain a series of corresponding symmetric points; points, a series of symmetrical points corresponding to these discrete points, and Connect the points in order to get the second arc .

[0105] In step 904, reference Figure 8 , the first clothoid curve , first arc , the second arc and the second clothoid Get the curve , that is, the combination of the first clothoid curve-target arc-second clothoid curve.

[0106] The process of processing the arc curve in the initial parking path provided in this embodiment can be referred to Figure 10 ,refer to Figure 8 , electronic devices execute Figure 10 The final parking path is obtained by following the process shown in FIG.

[0107] The technical solution provided in the embodiment of the present application processes each arc curve in the initial parking path through a geometric algorithm to obtain a curve with continuous curvature. The use of a geometric algorithm has high computational efficiency and strong practicality, and is suitable for engineering implementation.

[0108] Figure 11 This is a structural block diagram of a parking path processing device provided by an embodiment of the present application, such as Figure 11 Shown, including:

[0109] The circular arc curve determination module 110 is used to obtain an initial parking path of the vehicle and determine the circular arc curve in the initial parking path;

[0110] The arc curve processing module 120 is configured to process each arc curve into a combination of a first clothoid curve, a target arc, and a second clothoid curve, wherein the first endpoint of the first clothoid curve is the first endpoint of the arc curve, and the instantaneous radius of the first clothoid curve at the second endpoint is equal to the radius of the target arc; and the first clothoid curve and the second clothoid curve are symmetrical about a line connecting the midpoint of the target arc and the center of the circle in which the target arc is located;

[0111] The final parking path determining module 130 is configured to determine a final parking path according to a combination of the first clothoid curve, the target arc, and the second clothoid curve and a straight line portion in the initial parking path.

[0112] In one possible implementation, the arc curve processing module 120 includes:

[0113] A first determining unit is configured to determine, for each circular arc curve, the center of the circle in which the circular arc curve is located and a target straight line passing through the center of the circle in which the circular arc curve is located and a target midpoint, wherein the target midpoint is the midpoint of a line segment formed by two endpoints of the circular arc curve;

[0114] a second determining unit, configured to use the first endpoint of the circular arc curve as the first endpoint of a first clothoid curve, preset the arc length of the first clothoid curve to be a current preset arc length, and determine an initial second endpoint of the first clothoid curve based on the current preset arc length;

[0115] a third determining unit, configured to determine an intersection point of a normal line passing through the initial second endpoint and the target straight line as a target intersection point, and to determine a length between the target intersection point and the initial second endpoint as a radius of the target arc;

[0116] a judging unit, configured to judge whether the radius of the target arc and the instantaneous radius of the first clothoid curve at the initial second endpoint meet an equality condition;

[0117] a returning unit, configured to, if not, change the current preset arc length, set the changed arc length as the current preset arc length, return to the operation of setting the arc length of the first clothoid curve to the current preset arc length, determine the initial second endpoint of the first clothoid curve based on the current preset arc length, until the radius of the target arc meets the instantaneous radius, and set the last initial second endpoint as the second endpoint of the first clothoid curve;

[0118] a fourth determining unit, configured to determine a midpoint of the target arc; wherein the center of the circle on which the target arc lies is the target intersection point, and the first endpoint of the target arc is the second endpoint of the first clothoid curve;

[0119] A symmetry unit is used to perform a symmetry operation on the target curve based on the line between the midpoint of the target arc and the target intersection point to obtain a combination of a first spiral curve-target circular arc-second spiral curve; wherein the target curve is a curve obtained by combining a first spiral curve and a first arc obtained based on the first endpoint of the first spiral curve and the second endpoint of the first spiral curve; the first arc is an arc in the target arc between the second endpoint of the first spiral curve and the midpoint of the target arc.

[0120] In a possible implementation, the first determining unit is specifically configured to:

[0121] The center of the circle where the arc curve lies is determined based on the following formula:

[0122]

[0123] in, and are respectively the abscissa and ordinate of the center of the circle where the arc curve lies; 、 and are respectively the abscissa, ordinate and heading angle of the first endpoint of the circular arc curve; 、 and are respectively the ordinates of the second endpoints of the circular arc curve.

[0124] In a possible implementation manner, the second determining unit is specifically configured to:

[0125] The initial second endpoint of the first clothoid curve is determined based on the following formula:

[0126]

[0127] in, 、 and are respectively the abscissa, ordinate and heading angle of the initial second endpoint of the first clothoid curve in a coordinate system with the first endpoint of the circular arc curve as a vertex;

[0128] Where A is the parameter of the first clothoid curve, ;

[0129] in, is the maximum speed when parking, is the maximum steering wheel angle when parking, is the maximum corner speed when parking, , is the current preset arc length, The minimum turning radius for parking.

[0130] In a possible implementation manner, the third determining unit is specifically configured to:

[0131] The intersection point of the normal line of the initial second endpoint and the target straight line is determined based on the following formula:

[0132]

[0133] in, 、 are respectively the horizontal coordinate and the vertical coordinate of the target intersection point in the coordinate system with the first endpoint of the arc curve as the vertex, 、 are respectively the abscissa, ordinate and heading angle of the initial second endpoint in a coordinate system with the first endpoint of the circular arc curve as a vertex; ,in, is the slope of the target line; 、 are respectively the horizontal coordinate and the vertical coordinate of the target midpoint in the coordinate system with the first endpoint of the arc curve as the vertex, 、 are respectively the abscissa and ordinate of the center of the circle where the circular arc curve is located in a coordinate system with the first end point of the circular arc curve as the vertex.

[0134] In a possible implementation manner, the third determining unit is specifically configured to:

[0135] The length between the target intersection point and the initial second endpoint is determined based on the following formula:

[0136]

[0137] in, is the length between the target intersection point and the initial second endpoint, serving as the radius of the target arc, 、 are respectively the horizontal coordinate and the vertical coordinate of the target intersection point in the coordinate system with the first endpoint of the arc curve as the vertex, 、 are respectively the abscissa and ordinate of the initial second endpoint in a coordinate system with the first endpoint of the arc curve as a vertex.

[0138] In a possible implementation, the judgment unit is specifically configured to:

[0139] The following formula is used to determine whether the radius of the target arc and the instantaneous radius meet the equality condition:

[0140]

[0141] in, is the radius of the target arc, is the preset error value, is the instantaneous radius, A is the parameter of the first clothoid curve, where, ;

[0142] in, is the maximum speed when parking, is the maximum steering wheel angle when parking, is the maximum corner speed when parking, , is the current preset arc length, The minimum turning radius for parking.

[0143] In a possible implementation manner, the fourth determining unit is specifically configured to:

[0144] The midpoint of the target arc is determined based on the following formula:

[0145]

[0146] in, is the semi-center angle of the target arc; 、 and are respectively the abscissa, ordinate and heading angle of the midpoint of the target arc in a coordinate system with the first endpoint of the arc curve as the vertex; is the vector from the target intersection point to the target midpoint, is the vector from the target intersection point to the second endpoint of the first clothoid curve; is the radius of the target arc; 、 They are respectively the abscissa, ordinate and heading angle of the initial second endpoint in a coordinate system with the first endpoint of the arc curve as the vertex.

[0147] In one possible embodiment, the symmetry unit is specifically used to:

[0148] Determining the second endpoint of the first clothoid curve based on a symmetric point of a target symmetry line; wherein the target symmetry line is a line connecting the midpoint of the target circular arc to the target intersection point;

[0149] Determine, between the symmetry point and the second endpoint of the circular arc curve, a second clothoid curve that is symmetrical between the first clothoid curve and the target symmetry line;

[0150] Determine, between the midpoint of the target arc and the symmetry point, a second arc that is symmetrical to the target symmetry line based on the first arc;

[0151] The first clothoid curve, the first circular arc, the second circular arc, and the second clothoid curve form a combination of a first clothoid curve-a target circular arc-a second clothoid curve.

[0152] In a possible implementation, determining the second endpoint of the first clothoid curve based on a symmetric point of a target symmetry line includes:

[0153] The symmetry point is determined based on the following formula:

[0154]

[0155] in, and are respectively the abscissa and ordinate of the symmetrical point in a coordinate system with the first endpoint of the arc curve as a vertex; 、 and are respectively the abscissa, ordinate and heading angle of the midpoint of the target arc in a coordinate system with the first endpoint of the arc curve as the vertex; 、 are respectively the abscissa and ordinate of the initial second endpoint in a coordinate system with the first endpoint of the arc curve as a vertex.

[0156] like Figure 12 As shown, an embodiment of the present application provides an electronic device, including a processor 111, a communication interface 112, a memory 113 and a communication bus 114, wherein the processor 111, the communication interface 112, and the memory 113 communicate with each other through the communication bus 114.

[0157] Memory 113, for storing computer programs;

[0158] In one embodiment of the present application, the processor 111 is configured to execute a program stored in the memory 113 to implement the parking processing method provided by any of the aforementioned method embodiments, including:

[0159] Acquiring an initial parking path of the vehicle and determining an arc curve in the initial parking path;

[0160] Each circular arc curve is processed into a combination of a first clothoid curve, a target circular arc, and a second clothoid curve, wherein the first endpoint of the first clothoid curve is the first endpoint of the circular arc curve, and the instantaneous radius of the first clothoid curve at the second endpoint is equal to the radius of the target circular arc; the first clothoid curve and the second clothoid curve are symmetrical based on the line connecting the midpoint of the target circular arc and the center of the circle in which the target circular arc is located;

[0161] A final parking path is determined according to a combination of the first clothoid curve, the target circular arc, and the second clothoid curve and a straight line portion in the initial parking path.

[0162] An embodiment of the present application further provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the steps of the parking path processing method provided in any of the aforementioned method embodiments are implemented.

[0163] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of this embodiment.

[0164] Through the description of the above embodiments, those skilled in the art will clearly understand that each embodiment can be implemented using software plus a general hardware platform, or of course, hardware. Based on this understanding, the essence of the above technical solution, or the portion that contributes to the relevant technology, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a magnetic disk, or an optical disk, and includes a number of instructions for causing a computer device (such as a personal computer, server, or network device) to execute the methods described in each embodiment or certain portions of the embodiments.

[0165] It should be understood that the terms used herein are for the purpose of describing specific example embodiments only and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "one", "an" and "said" as used herein may also be meant to include plural forms. The terms "comprise", "include", "contain" and "have" are inclusive and therefore specify the presence of stated features, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, steps, operations, elements, parts, and / or combinations thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring them to be performed in the specific order described or illustrated, unless the order of execution is clearly indicated. It should also be understood that additional or alternative steps may be used.

[0166] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the broadest scope consistent with the principles and novel features of the present application.

Claims

1. A parking path processing method, characterized in that: include: Acquiring an initial parking path of the vehicle and determining an arc curve in the initial parking path; Each circular arc curve is processed into a combination of a first clothoid curve-a target circular arc-a second clothoid curve, wherein the first endpoint of the first clothoid curve is the first endpoint of the circular arc curve, and the instantaneous radius of the first clothoid curve at the second endpoint is equal to the radius of the target circular arc; the first clothoid curve and the second clothoid curve are symmetrical based on the line connecting the midpoint of the target circular arc and the center of the circle where the target circular arc is located; wherein the first endpoint of the circular arc curve is used as the first endpoint of the first clothoid curve, and the second endpoint of the first clothoid curve is continuously explored by a calculation method until the first clothoid curve is When the instantaneous radius of the line at the second endpoint meets the radius of the target arc, the second endpoint of the first clothoid curve at this time is used as the second endpoint of the first clothoid curve finally determined; after determining the first clothoid curve, the midpoint of the target arc is calculated, and a symmetry operation is performed on the combined curve formed by the first clothoid curve and the first arc based on the line between the midpoint of the target arc and the center of the circle where the target arc is located, to obtain a second arc symmetrical to the first arc, and to obtain a second clothoid curve symmetrical to the first clothoid curve, the first arc being the arc from the second endpoint of the first clothoid curve to the midpoint in the target arc; A final parking path is determined according to a combination of the first clothoid curve, the target circular arc, and the second clothoid curve and a straight line portion in the initial parking path.

2. The method according to claim 1, characterized in that The step of processing each circular arc curve into a combination of a first clothoid curve, a target circular arc, and a second clothoid curve comprises: For each circular arc curve, determine the center of the circle in which the circular arc curve is located and determine a target straight line passing through the center of the circle in which the circular arc curve is located and a target midpoint, wherein the target midpoint is the midpoint of a line segment formed by the two endpoints of the circular arc curve; Using the first endpoint of the circular arc curve as the first endpoint of a first clothoid curve, presetting the arc length of the first clothoid curve to a current preset arc length, and determining an initial second endpoint of the first clothoid curve based on the current preset arc length; Determine an intersection point of a normal line passing through the initial second endpoint and the target straight line as a target intersection point, and determine a length between the target intersection point and the initial second endpoint as a radius of the target arc; Determining whether the radius of the target arc and the instantaneous radius of the first clothoid curve at the initial second endpoint meet an equality condition; If not, changing the current preset arc length, using the changed arc length as the current preset arc length, returning to the operation of presetting the arc length of the first clothoid curve as the current preset arc length, and determining the initial second endpoint of the first clothoid curve based on the current preset arc length until the radius of the target arc meets the instantaneous radius, and using the last initial second endpoint as the second endpoint of the first clothoid curve; Determine the midpoint of the target arc; wherein the center of the circle on which the target arc lies is the target intersection point, and the first endpoint of the target arc is the second endpoint of the first clothoid curve; The target curve is symmetrically operated based on the line connecting the midpoint of the target arc to the target intersection point to obtain a combination of the first spiral curve-target arc-second spiral curve; wherein the target curve is a curve obtained by combining the first spiral curve and the first arc obtained based on the first endpoint of the first spiral curve and the second endpoint of the first spiral curve; the first arc is the arc between the second endpoint of the first spiral curve and the midpoint of the target arc in the target arc.

3. The method according to claim 2, characterized in that Determining the center of the circle where the arc curve lies includes: The center of the circle where the arc curve lies is determined based on the following formula: in, and are respectively the abscissa and ordinate of the center of the circle where the arc curve lies; 、 and are respectively the abscissa, ordinate and heading angle of the first endpoint of the circular arc curve; 、 and are respectively the ordinates of the second endpoints of the circular arc curve.

4. The method according to claim 2, characterized in that The determining the initial second endpoint of the first clothoid curve based on the current preset arc length includes: The initial second endpoint of the first clothoid curve is determined based on the following formula: in, 、 and are respectively the abscissa, ordinate and heading angle of the initial second endpoint of the first clothoid curve in a coordinate system with the first endpoint of the circular arc curve as a vertex; Where A is the parameter of the first clothoid curve, ; in, is the maximum speed when parking, is the maximum steering wheel angle when parking, is the maximum corner speed when parking, , is the current preset arc length, The minimum turning radius for parking.

5. The method according to claim 2, characterized in that Determining the intersection point of the normal line passing through the initial second endpoint and the target straight line includes: The intersection point of the normal line of the initial second endpoint and the target straight line is determined based on the following formula: in, 、 are respectively the horizontal coordinate and the vertical coordinate of the target intersection point in the coordinate system with the first endpoint of the arc curve as the vertex, 、 are respectively the abscissa, ordinate and heading angle of the initial second endpoint in a coordinate system with the first endpoint of the circular arc curve as a vertex; ,in, is the slope of the target line; 、 are respectively the horizontal coordinate and the vertical coordinate of the target midpoint in the coordinate system with the first endpoint of the arc curve as the vertex, 、 are respectively the abscissa and ordinate of the center of the circle where the circular arc curve is located in a coordinate system with the first end point of the circular arc curve as the vertex.

6. The method according to claim 2, characterized in that Determining the length between the target intersection point and the initial second endpoint includes: The length between the target intersection point and the initial second endpoint is determined based on the following formula: in, is the length between the target intersection point and the initial second endpoint, serving as the radius of the target arc, 、 are respectively the horizontal coordinate and the vertical coordinate of the target intersection point in the coordinate system with the first endpoint of the arc curve as the vertex, 、 are respectively the abscissa and ordinate of the initial second endpoint in a coordinate system with the first endpoint of the arc curve as a vertex.

7. The method according to claim 2, characterized in that The determining whether the radius of the target arc and the instantaneous radius of the first clothoid curve at the initial second endpoint meet an equality condition includes: The following formula is used to determine whether the radius of the target arc and the instantaneous radius meet the equality condition: in, is the radius of the target arc, is the preset error value, is the instantaneous radius, A is the parameter of the first clothoid curve, where, ; in, is the maximum speed when parking, is the maximum steering wheel angle when parking, is the maximum corner speed when parking, , is the current preset arc length, The minimum turning radius for parking.

8. The method according to claim 2, characterized in that Determining the midpoint of the target arc includes: The midpoint of the target arc is determined based on the following formula: in, is the semi-center angle of the target arc; 、 and are respectively the abscissa, ordinate and heading angle of the midpoint of the target arc in a coordinate system with the first endpoint of the arc curve as the vertex; is the vector from the target intersection point to the target midpoint, is the vector from the target intersection point to the second endpoint of the first clothoid curve; is the radius of the target arc; 、 They are respectively the abscissa, ordinate and heading angle of the initial second endpoint in a coordinate system with the first endpoint of the arc curve as the vertex.

9. The method according to claim 2, characterized in that The step of performing a symmetric operation on the target curve based on a line connecting the midpoint of the target arc to the target intersection point to obtain a combination of a first clothoid curve, a target arc, and a second clothoid curve comprises: Determining the second endpoint of the first clothoid curve based on a symmetric point of a target symmetry line; wherein the target symmetry line is a line connecting the midpoint of the target circular arc to the target intersection point; Determine, between the symmetry point and the second endpoint of the circular arc curve, a second clothoid curve that is symmetrical between the first clothoid curve and the target symmetry line; Determine, between the midpoint of the target arc and the symmetry point, a second arc that is symmetrical to the target symmetry line based on the first arc; The first clothoid curve, the first circular arc, the second circular arc, and the second clothoid curve form a combination of a first clothoid curve-a target circular arc-a second clothoid curve.

10. The method according to claim 9, characterized in that Determining the second endpoint of the first clothoid curve based on a symmetric point of a target symmetry line includes: The symmetry point is determined based on the following formula: in, and are respectively the abscissa and ordinate of the symmetrical point in a coordinate system with the first endpoint of the arc curve as a vertex; 、 and are respectively the abscissa, ordinate and heading angle of the midpoint of the target arc in a coordinate system with the first endpoint of the arc curve as the vertex; 、 are respectively the abscissa and ordinate of the initial second endpoint in a coordinate system with the first endpoint of the arc curve as a vertex.

11. A parking path processing device, characterized in that: include: a circular arc curve determination module, configured to obtain an initial parking path of the vehicle and determine a circular arc curve in the initial parking path; The arc curve processing module is used to process each arc curve into a combination of a first clothoid curve, a target arc, and a second clothoid curve, wherein the first endpoint of the first clothoid curve is the first endpoint of the arc curve, and the instantaneous radius of the first clothoid curve at the second endpoint is equal to the radius of the target arc; the first clothoid curve and the second clothoid curve are symmetrical based on the line connecting the midpoint of the target arc and the center of the circle where the target arc is located; wherein the first endpoint of the arc curve is used as the first endpoint of the first clothoid curve, and the second endpoint of the first clothoid curve is continuously explored by a calculation method until When the instantaneous radius of the first clothoid curve at the second endpoint meets the radius of the target arc, the second endpoint of the first clothoid curve at this time is used as the second endpoint of the first clothoid curve finally determined; after determining the first clothoid curve, the midpoint of the target arc is calculated, and a symmetry operation is performed on the combined curve formed by the first clothoid curve and the first arc based on the line between the midpoint of the target arc and the center of the circle where the target arc is located, so as to obtain a second arc symmetrical to the first arc, and obtain a second clothoid curve symmetrical to the first clothoid curve, wherein the first arc is the arc from the second endpoint of the first clothoid curve to the midpoint in the target arc; The final parking path determining module is configured to determine a final parking path according to a combination of the first clothoid curve, the target circular arc, and the second clothoid curve and a straight line portion in the initial parking path.

12. An electronic device, characterized in that: include: memory for storing computer programs; A processor, configured to execute a computer program stored in the memory, and when the computer program is executed, implement the method according to any one of claims 1 to 10.

13. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 10 is implemented.

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