An automatic parking path planning method for a vehicle

Abstract

The application provides an automatic parking path planning method for a vehicle, which is a method for generating a parking reference path based on an initial pose of the vehicle and a storage location. The generated reference path is a combined curve composed of a straight line segment, a curve and a straight line segment, wherein the curve is a Bezier curve. The starting point of the combined curve is the initial parking position, and the ending point is the midpoint position of the bottom line of the parking garage. The path planning method is simple and easy to implement, has good versatility, and is suitable for various parking scenarios such as vertical parking, diagonal parking and parallel parking.

Description

Technical Field

[0001] This invention belongs to the field of autonomous driving technology, and in particular relates to a method for automatic parking path planning for automobiles. Background Technology

[0002] With the development of science and technology and people's increasing demands for travel quality, the development and application of autonomous driving technology are becoming increasingly widespread. Automated parking is a crucial component of autonomous driving technology. Due to the involvement of multiple technical aspects such as parking space recognition, path planning, and path following, the implementation of automated parking has always been a technical challenge. Current research has yielded a relatively rich array of automated parking path planning algorithms, but due to constraints such as curvature, continuity, parking space, and path adjustability, they all have their own shortcomings. In practical applications, they cannot achieve satisfactory parking results, and often the same path planning method is not applicable to different parking scenarios. Summary of the Invention

[0003] This invention provides a method for automatic parking path planning for automobiles. The method generates a parking path based on the initial parking pose of the vehicle and the parking space. The generated planned path is a composite curve composed of straight line segments, curves, and straight line segments, where the curves are Bezier curves. The starting point of the composite curve is the initial parking position, and the ending point is the midpoint of the parking space's baseline. This invention is specifically implemented through the following technical solutions:

[0004] The first aspect of this invention provides a method for automatic parking path planning for automobiles, the method comprising the following steps:

[0005] S1: Determine the parking space location, i.e., determine the midpoint of the parking garage's baseline (P). e (x e ,y e )) and garage direction (θ) e );

[0006] S2: Determine the initial parking position, i.e., determine the starting position of the vehicle parking (P). s (x s ,y s )) and vehicle direction (θ) s );

[0007] S3: Solve for the intersection point (P) of the straight line determined by the parking location and the straight line determined by the initial parking pose. c (x c ,y c ));

[0008] S4: Solve for the line segment (a) determined by the intersection point and the starting point of the vehicle parking. s ) length (L) sSolve for the line segment (a) determined by the intersection point and the midpoint of the parking garage baseline. e ) length (L) e );

[0009] S5: Determine the curved portion of the planned path: on the line segment (a s ) and the line segment (a) e The control points of the Bezier curve are marked out, and then the Bezier curve is determined.

[0010] S6: Determine the straight segment of the planned path: based on the intersection point and the line segment (a) s The line segment (a) of the Bezier curve defined by the furthest control point is the distance from the point on the curve. sn The total length L sn Calculate the length (L) of the initial straight line segment. s1 ):L s1 =L s -L sn According to the intersection point and the line segment (a) e The line segment (a) of the Bezier curve defined by the furthest control point is the distance from the point on the curve. en The total length L en Calculate the length (L) of the final straight segment. e1 ):L e1 =L e -L en ;

[0011] S7: The combined curve, i.e. the parking planning path, can be obtained from the determined initial straight segment, the curved part, and the final straight segment.

[0012] As a further explanation of the present invention, the Bezier curve is determined by odd-numbered multi-order Bezier parametric equations.

[0013] As a further illustration of the present invention, the Bezier curve is determined by an odd-order Bezier parametric equation of at least fifth order.

[0014] As a further illustration of the present invention, the method is applicable to both perpendicular parking scenarios and angled parking scenarios.

[0015] As a further illustration of the present invention, the combined curve obtained by the method has a smooth connection between the straight line segment and the curved segment, and satisfies at least fifth-order continuity.

[0016] As a further explanation of the present invention, the planned path determined by the method needs to be discretized in practical applications, that is, discrete points are generated, and the path contains position and direction information at each point.

[0017] As a further explanation of the present invention, in the above path planning method, each control point of the Bezier curve is marked by a line segment length. Furthermore, the control points can also be determined proportionally, that is, the length of each marked segment is taken as a proportion of the total length. This proportion can vary or be evenly distributed.

[0018] A second aspect of the present invention provides a method for automatic parking path planning of automobiles applicable to parallel parking scenarios, the method comprising the following steps:

[0019] S1: Determine the parking space location, i.e., determine the midpoint of the parking garage's baseline (P). e (x e ,y e )) and library direction (θ) e );

[0020] S2: Determine the initial parking position, i.e., determine the starting position of the vehicle parking (P). s (x s ,y s )) and vehicle direction (θ) s );

[0021] S3: Assume the location of the center control point of the Bezier curve is P. m (x m ,y m );

[0022] S4: The straight line and the straight line y = x determined based on the initial parking pose. m Solve for their intersection point (P) cs (x m ,y cs The straight line and the straight line y = x determined based on the storage location. m Solve for their intersection point (P) ce (x m ,y ce ));

[0023] S5: Solve for the intersection point (P) cs (x m ,y cs )) and the intersection point (P) ce (x m ,y ce The determined line segment length L cc ;

[0024] S6: Let x m =x e +a*L cc , making y m =y ce +1 / 2*L cc; Calibrate a, determine the location P of the center control point of the Bezier curve. m (x m ,y m );

[0025] S7: Solve for the intersection point (P) cs (x m ,y cs The line segment (a) determined by the two points, namely the starting point of the vehicle parking and the starting point of the parking. s ) length (L) s Solve for the intersection point (P). ce (x m ,y ce The line segment (a) determined by the two points (a) and the midpoint of the bottom line of the parking garage. e ) length (L) e );

[0026] S8: Determine the curved portion of the planned path: in the line segment (a s ) and the line segment (a) e The control points of the Bezier curve are marked out, and then the Bezier curve is determined.

[0027] S9: Determine the straight segment of the planned path: based on the intersection point (P) cs (x m ,y cs )) and in the line segment (a s The line segment (a) of the Bezier curve defined by the furthest control point is the distance from the point on the curve. sn The total length L sn Calculate the length (L) of the initial straight line segment. s1 ):L s1 =L s -L sn According to the intersection point (P) ce (x m ,y ce )) and in the line segment (a e The line segment (a) of the Bezier curve defined by the furthest control point is the distance from the point on the curve. en The total length L en Calculate the length (L) of the final straight segment. e1 ):L e1 =L e -L en ;

[0028] S10: The combined curve, i.e. the parking planning path, can be obtained from the determined initial straight segment, the curved portion, and the final straight segment.

[0029] As a further explanation of the present invention, the Bezier curve is determined by an even-numbered multi-order Bezier parametric equation.

[0030] As a further illustration of the present invention, the Bezier curve is determined by an even-order Bezier parametric equation of at least sixth order.

[0031] Compared with the prior art, the present invention has the following beneficial technical effects:

[0032] (1) The planned path of the automatic parking path planning method of the present invention can be adjusted according to parameter calibration;

[0033] (2) The automatic parking path planning method of the present invention has good path smoothness and high-order continuity.

[0034] (3) The automatic parking path planning method of the present invention has good versatility and is applicable to multiple parking scenarios such as perpendicular parking, diagonal parking, and parallel parking. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of an automatic parking path planning method for automobiles, taking a vertical parking scenario as an example, provided in Embodiment 1 of the present invention;

[0036] Figure 2 This is a flowchart of an automatic parking path planning method for automobiles, taking a vertical parking scenario as an example, provided in Embodiment 1 of the present invention;

[0037] Figure 3 This is a schematic diagram of the automatic parking path planning method for automobiles, taking parallel parking as an example, provided in Embodiment 2 of the present invention;

[0038] Figure 4 This is a flowchart of an automatic parking path planning method for automobiles, taking a parallel parking scenario as an example, provided in Embodiment 2 of the present invention. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0040] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0041] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0042] The technical solution of the present invention will be explained below with reference to specific embodiments.

[0043] This invention provides a method for automatic parking path planning for automobiles. The method generates a parking path based on the initial parking pose of the vehicle and the parking space. The generated planned path is a composite curve composed of straight line segments, curves, and straight line segments, where the curves are Bezier curves. The starting point of the composite curve is the initial parking position, and the ending point is the midpoint of the parking space's baseline.

[0044] Example 1:

[0045] This paper provides a method for automatic parking path planning for cars, applicable to both perpendicular and angled parking scenarios. Figure 1 and 2 The process of automatic parking path planning for a car is illustrated using a vertical parking scenario as an example. In this embodiment, the Bezier curve is determined by a fifth-order Bezier parametric equation.

[0046] like Figure 1 and 2 As shown, a method for automatic parking path planning for automobiles is provided, the method comprising the following steps:

[0047] S1: Determine the parking space location, i.e., determine the midpoint of the parking garage's baseline (P). e (x e ,y e )) and garage direction (θ) e );

[0048] S2: Determine the initial parking position, i.e., determine the starting position of the vehicle parking (P). s (x s ,y s )) and vehicle direction (θ) s );

[0049] S3: Solve for the intersection point (P) of the straight line determined by the parking location and the straight line determined by the initial parking pose. c (x c ,y c ));

[0050] S4: Solve for the line segment (a) determined by the intersection point and the starting point of the vehicle parking. s ) length (L) s Solve for the line segment (a) determined by the intersection point and the midpoint of the parking garage baseline. e) length (L) e );

[0051] S5: Determine the curved portion of the planned path: on the line segment (a s L1, L2, and L3 are marked in the line segment (a) e L4, L5, and L6 are identified, and then the control points of the Bezier curve are determined, namely P1(x1,y1), P2(x2,y2), P3(x3,y3), P4(x4,y4), P5(x5,y5), and P6(x6,y6), thus determining the Bezier curve.

[0052] S6: Determine the straight segment of the planned path: Calculate L s1 =L s -L1-L2-L3 determine the initial straight line segment, and calculate L. e6 =L e -L4-L5-L6 determine the final straight segment;

[0053] S7: The combined curve, i.e. the parking planning path, can be obtained from the determined initial straight segment, the curved part, and the final straight segment.

[0054] In the above steps:

[0055]

[0056] y c =tanθ s *x c +y s -tanθ s *x s

[0057]

[0058]

[0059]

[0060]

[0061]

[0062]

[0063]

[0064]

[0065] The fifth-order Bezier parameter equation for the above Bezier curve is:

[0066] B(t)=(1-t) 5 *P1+5*(1-t) 4 *t*P2+10*(1-t) 3 *t 2 *P3+10*(1-t) 2 *t 3 *P4+5*(1-t)*t 4 *P5+t 5 *P6

[0067] In the formula, t∈[0,1], and P1, P2, P3, P4, P5, and P6 are the control points of the Bezier curve.

[0068] The planned path determined in Example 1 above needs to be discretized in practical applications, that is, discrete points need to be generated. At each point, the path contains information such as position and direction. Specifically:

[0069] Curved section:

[0070]

[0071] In the formula, t∈[0,1], within this interval, by taking values ​​of t at certain intervals, the discrete points of the curve can be obtained.

[0072] Initial segment: straight line segment

[0073]

[0074] In the formula, m∈(0,1], within this interval, m is taken at certain intervals to obtain the discrete points of the initial straight line segment.

[0075] The final straight segment:

[0076]

[0077] In the formula, n∈(0,1], within this interval, n is taken at certain intervals to obtain the discrete points of the last straight line segment.

[0078] Example 2

[0079] This paper provides a method for automatic parking path planning of cars suitable for parallel parking scenarios. Figure 3 and 4 The automatic parking path planning process of a car is illustrated using a parallel parking scenario as an example. In this embodiment, the Bezier curve is determined by a sixth-order Bezier parametric equation.

[0080] like Figure 3 and 4As shown, an automatic parking path planning method for cars suitable for parallel parking scenarios is provided. The method includes the following steps:

[0081] S1: Determine the parking space location, i.e., determine the midpoint of the parking garage's baseline (P). e (x e ,y e )) and library direction (θ) e );

[0082] S2: Determine the initial parking position, i.e., determine the starting position of the vehicle parking (P). s (x s ,y s )) and vehicle direction (θ) s );

[0083] S3: Assume the center control point of the Bezier curve is located at P4(x4,y4);

[0084] S4: Based on the initial parking pose, determine the intersection point (P) of the straight line and the straight line y = x4. cs (x4,y cs ));

[0085] S5: Based on the line determined by the storage location and the line y = x4, solve for their intersection point (P). ce (x4,y ce ));

[0086] S6: Solve for the intersection point (P) cs (x4,y cs )) and the intersection point (P) ce (x4,y ce The determined line segment length L cc ;

[0087] S7: Let x4 = x e +a*L cc Let y4 = y ce +1 / 2*L cc ;

[0088] S8: Calibrate a, determine the position of the center control point P4(x4, y4) of the Bezier curve;

[0089] S9: Solve for the intersection point (P) cs (x4, y cs The line segment (a) determined by the two points, namely the starting point of the vehicle parking and the starting point of the parking. s ) length (L) s Solve for the intersection point (P). ce (x4, y ce The line segment (a) determined by the two points (a) and the midpoint of the bottom line of the parking garage.e ) length (L) e );

[0090] S10: Determine the curved portion of the planned path: in the line segment (a s L1, L2, and L3 are marked in the line segment (a) e L4, L5, and L6 are identified, and then the control points of the Bezier curve are determined, namely P1(x1, y1), P2(x2, y2), P3(x3, y3), P5(x5, y5), P6(x6, y6), and P7(x7, y7), thus determining the Bezier curve.

[0091] S11: Determine the straight segment of the planned path: Calculate L s1 =L s -L1-L2-L3 determine the initial straight line segment, and calculate L. e7 =L e -L4-L5-L6 determine the final straight segment;

[0092] S12: The combined curve, i.e. the parking planning path, can be obtained from the determined initial straight segment, the curved portion, and the final straight segment.

[0093] In the above steps:

[0094] y cs =tanθ s *x4+y s -tanθ s *x s

[0095] y ce =tanθ e *x4+y e -tanθ e *x e

[0096] L cc =(tanθ) s *x4+y s -tanθ s *x s )-(tanθ e *x4+y e -tanθ e *x e )

[0097]

[0098]

[0099]

[0100]

[0101]

[0102]

[0103]

[0104]

[0105]

[0106] The sixth-order Bezier parameter equation for the above Bezier curve is:

[0107] B(t)=(1-t) 6 *P1+6*(1-t) 5 *t*P2+15*(1-t) 4 *t 2 *P3+20*(1-t) 3 *t 3 *P4+15*(1-t) 2 *t 4 *P5+6*(1-t)*t 5 *P6+t 6 *P7

[0108] In the formula, t∈[0,1], and P1, P2, P3, P4, P5, P6, and P7 are the control points of the Bezier curve.

[0109] The above-mentioned combination curve satisfies sixth-order continuity, and its discretization method is the same as that of the combination curve obtained by the above method.

[0110] The embodiments given above are preferred examples for implementing the present invention, and the present invention is not limited to the above embodiments. Any non-essential additions or substitutions made by those skilled in the art based on the technical features of the present invention are within the protection scope of the present invention.

Claims

1. A method for automatic parking path planning for automobiles, characterized in that, The method includes the following steps: S1: Determine the parking space location, i.e., determine the midpoint of the parking garage's baseline (P). e (x) e ,y e )) and garage direction (θ) e ); S2: Determine the initial parking position, i.e., determine the starting position of the vehicle parking (P). s (x) s ,y s )) and vehicle direction (θ) s ); S3: Solve for the intersection point (P) of the straight line determined by the parking location and the straight line determined by the initial parking pose. c (x) c ,y c )); S4: Solve for the line segment (a) determined by the intersection point and the starting point of the vehicle parking. s ) length (L s ), solve for the line segment (a) determined by the intersection point and the midpoint of the parking garage baseline. e ) length (L e ); S5: Determine the curved portion of the planned path: on the line segment (a s L1, L2, and L3 are labeled in the line segment (a) e L4, L5, and L6 are marked in the diagram, and then the control points of the Bezier curve are determined, namely P1(x1,y1), P2(x2,y2), P3(x3,y3), P4(x4,y4), P5(x5,y5), and P6(x6,y6), thus determining the Bezier curve. In the path planning method, the control points of the Bezier curve are marked by the length of the line segment. The control points are determined by a proportional method, either evenly distributed or with different proportions. S6: Determine the straight segment of the planned path: based on the intersection point and the line segment (a) s The line segment (a) of the Bezier curve defined by the furthest control point is the distance from the point on the curve. sn The total length L sn Calculate the length (L) of the initial straight line segment. s1 ):L s1 =L s -L sn According to the intersection point and the line segment (a) e The line segment (a) of the Bezier curve defined by the furthest control point is the distance from the point on the curve. en The total length L en Calculate the length (L) of the final straight segment. e1 ):L e1 =L e -L en ; S7: The combined curve, i.e. the parking planning path, can be obtained from the determined initial straight segment, the curved part, and the final straight segment.

2. The automatic parking path planning method for automobiles according to claim 1, characterized in that, The Bezier curve is determined by odd-numbered multi-order Bezier parametric equations.

3. The automatic parking path planning method for automobiles according to claim 1, characterized in that, The Bezier curve is determined by an odd-order Bezier parametric equation of at least fifth order.

4. The automatic parking path planning method for automobiles according to claim 1, characterized in that, The method is applicable to both perpendicular parking and angled parking scenarios.

5. The automatic parking path planning method for automobiles according to claim 1, characterized in that, The combined curve obtained by the method has a smooth connection between the straight line segment and the curved segment, and satisfies at least fifth-order continuity.

6. The automatic parking path planning method for automobiles according to claim 1, characterized in that: The planned path determined by the method needs to be discretized in practical applications, that is, discrete points are generated, and the path contains position and direction information at each point.

7. A method for automatic parking path planning for cars applicable to parallel parking scenarios, characterized in that, The method includes the following steps: S1: Determine the parking space location, i.e., determine the midpoint of the parking garage's baseline (P). e (x) e ,y e )) and library direction (θ) e ); S2: Determine the initial parking position, i.e., determine the starting position of the vehicle parking (P). s (x) s ,y s )) and vehicle direction (θ) s S3: Assume the location of the center control point P of the Bezier curve. m (x) m ,y m ); S4: The straight line and the straight line y=x determined based on the initial parking pose. m Solve for their intersection point (P) cs (x) m ,y cs The straight line and the straight line y=x determined based on the storage location. m Solve for their intersection point (P) ce (x) m ,y ce )); S5: Solve for the intersection point (P) cs (x) m ,y cs )) and the intersection point (P) ce (x) m ,y ce The determined line segment length L cc ; S6: Let x m =x e +a L cc , making y m =y ce +1 / 2 L cc ; Calibrate a, determine the location P of the center control point of the Bezier curve. m (x) m ,y m ); S7: Solve for the intersection point (P) cs (x) m ,y cs The line segment (a) determined by the two points, namely the starting point of the vehicle parking and the starting point of the parking. s ) length (L s Solve for the intersection point (P). ce (x) m ,y ce The line segment (a) determined by the two points (a) and the midpoint of the bottom line of the parking garage. e ) length (L e ); S8: Determine the curved portion of the planned path: on the line segment (a s L1, L2, and L3 are labeled in the line segment (a) e L4, L5, and L6 are marked in the diagram, and then the control points of the Bezier curve are determined, namely P1(x1,y1), P2(x2,y2), P3(x3,y3), P5(x5,y5), P6(x6,y6), and P7(x7,y7), thus determining the Bezier curve. In the path planning method, the control points of the Bezier curve are marked by the length of the line segment. The control points are determined by a proportional method, either evenly distributed or with different proportions. S9: Determine the straight segment of the planned path: based on the intersection point (P) cs (x) m ,y cs )) and in the line segment (a s The line segment (a) of the Bezier curve defined by the furthest control point is the distance from the point on the curve. sn The total length L sn Calculate the length (L) of the initial straight line segment. s1 ):L s1 =L s -L sn According to the intersection point (P) ce (x) m ,y ce )) and in the line segment (a e The line segment (a) of the Bezier curve defined by the furthest control point is the distance from the point on the curve. en The total length L en Calculate the length (L) of the final straight segment. e1 ):L e1 =L e -L en ; S10: The combined curve, i.e. the parking planning path, can be obtained from the determined initial straight segment, the curved portion, and the final straight segment.

8. The automatic parking path planning method for parallel parking scenarios according to claim 7, characterized in that, The Bezier curve is determined by an even-numbered multi-order Bezier parametric equation.

9. The automatic parking path planning method for parallel parking scenarios according to claim 7, characterized in that, The Bezier curve is determined by an even-order Bezier parametric equation of at least sixth order.

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