Method and device for full-coverage operation path planning and optimization of agricultural machinery in farmland scenarios

Abstract

The present invention provides a method and device for planning and optimizing the full-coverage operation path of agricultural machinery in a farmland scenario, belonging to the fields of autonomous driving and path planning, including: dividing the farmland into an in-field operation area and a headland area based on the coordinates of each vertex of the polygonal farmland, the maximum curvature of the unmanned operation agricultural machinery itself, and the operation type; dividing the in-field operation area into full-coverage operation strips based on the operation width of the unmanned operation agricultural machinery and the operation starting point and operation orientation when entering the farmland to form a basic path of the operation strip; determining the turning path of the headland area according to the turning radius and the turning starting point of the operation strip; determining the edge-closing path of the headland area according to the basic path of the operation strip and the turning path of the headland, so as to generate a full-coverage path of the farmland and generate a path file. The present invention improves the operation efficiency of agricultural machinery.

Description

Technical Field

[0001] The present invention relates to the fields of autonomous driving and path planning, and particularly to a method and device for path planning and optimization of full-coverage operation of agricultural machinery in a farmland scenario. Background Art

[0002] In a real farm environment, unmanned agricultural machinery is restricted by the distribution of tractor roads and farmland and the shape of the farmland. It is necessary to carry out full-coverage operation path planning starting from a specific starting point and in a specific direction to improve the operation efficiency of agricultural machinery and achieve the goal of cost savings and improved operation quality. Most of the existing agricultural machinery operation path planning studies focus on single issues such as the path planning of quadrilateral farmland AB line, turning at the headland corner, or obstacle handling, and most of them are used for simulation. There is a lack of systematic consideration of the application requirements of real farms.

[0003] In the prior art, there are already various methods for full-coverage path planning of farmland. Common ones include the straight reciprocating coverage method (Boustrophedon path), curved coverage path, partition-based path planning, etc. Most of these methods assume that the shape of the farmland plot is regular (such as rectangular or trapezoidal), or allow agricultural machinery to operate in any orientation, thus simplifying the complexity of path planning. However, in actual farm production, the operation of agricultural machinery is affected by various constraints such as irregular plot shapes, crop planting directions, obstacle distributions, etc. Especially in the scenario of unmanned farms, higher requirements are put forward for the accuracy and executability of paths. Most of the existing path planning methods are only based on geometric path planning, ignoring the influence of the turning radius of agricultural machinery, speed changes, operation width, and operation modes (such as sowing, spraying) on path feasibility, resulting in difficulties in tracking the planned path during execution, affecting operation quality. Moreover, many methods are only applicable to ideal regular plots. For complex plots with irregular shapes, there are prone to dead ends or redundant paths in path planning, or it is difficult to achieve a high coverage rate, reducing operation efficiency. Summary of the Invention

[0004] To solve the above problems of not considering the dynamic characteristics of agricultural machinery and poor adaptability to complex plots, the present invention provides a method and device for path planning and optimization of full-coverage operation of agricultural machinery in a farmland scenario.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for path planning and optimization of full-coverage operation of agricultural machinery in a farmland scenario includes the following steps:

[0007] Step 1: Divide the farmland into an in-field operation area and a headland area based on the vertex coordinates of the polygonal farmland, the maximum curvature of the unmanned operation agricultural machinery itself, and the operation type;

[0008] Step 2: Based on the working width of the unmanned agricultural machinery, the starting point of operation in the farmland, and the operation orientation, perform full-coverage operation strip segmentation on the in-field operation area to form the basic path of the operation strip;

[0009] Step 3: According to the turning radius and the starting point of the operation strip turning, determine the turning path in the cape area through the improved Dubins curve algorithm;

[0010] Step 4: Determine the edge-trimming path in the cape area according to the basic path of the operation strip generated in Step 2 and the turning path in the cape area determined in Step 3, so as to generate the full-coverage path of the farmland and generate a path file.

[0011] The present invention also provides a device for planning and optimizing the full-coverage operation path of agricultural machinery in a farmland scenario, including the following modules:

[0012] The zoning module divides the farmland into an in-field operation area and a cape area based on the coordinates of each vertex of the polygonal farmland, the maximum curvature of the unmanned agricultural machinery itself, and the operation type;

[0013] The full-coverage operation strip segmentation module performs full-coverage operation strip segmentation on the in-field operation area based on the working width of the unmanned agricultural machinery, the starting point of operation in the farmland, and the operation orientation, to form the basic path of the operation strip;

[0014] The turning path determination module determines the turning path in the cape area through the improved Dubins curve algorithm according to the turning radius and the starting point of the operation strip turning;

[0015] The full-coverage path generation module determines the edge-trimming path in the cape area according to the basic path of the operation strip and the turning path in the cape area, so as to generate the full-coverage path of the farmland and generate a path file.

[0016] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, the steps of the above-mentioned method for planning and optimizing the full-coverage operation path of agricultural machinery in a farmland scenario are implemented.

[0017] The present invention also provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the above-mentioned method for planning and optimizing the full-coverage operation path of agricultural machinery in a farmland scenario are implemented.

[0018] Beneficial effects:

[0019] (1) Based on the parameters of the unmanned agricultural machinery itself, the present invention optimizes the division method of the operation area and the cape edge-trimming area of the convex polygonal farmland, and clarifies the implementation plan for unmanned operation in the farmland.

[0020] (2)The present invention adopts the idea of a virtual circumscribed quadrilateral and combines the parameters of unmanned agricultural machinery to solve the full-coverage operation strips in the field operation area and the maximum coverage edge-collecting path in the cape edge-collecting area.

[0021] (3)The present invention solves the turning path in the cape area according to the width of the cape area, the curvature constraint of the agricultural machinery, and the strip traversal scheme. Brief Description of the Drawings

[0022] Figure 1 is the schematic diagram of the principle of the agricultural machinery full-coverage operation path planning and optimization method in a farmland scenario of the present invention;

[0023] Figure 2 is the schematic diagram of the division of the operation area and the cape area;

[0024] Figure 3 is the schematic diagram of finding the boundary points by constructing a virtual rectangle based on the operation orientation;

[0025] Figure 4 is the schematic diagram of solving the turning path by the conventional Dubins algorithm;

[0026] Figure 5 is the schematic diagram of solving the turning path by the improved Dubins algorithm;

[0027] Figure 6 is the schematic diagram of smoothing both ends of the vertex in the cape edge-collecting area;

[0028] Figure 7 is the schematic diagram of the in-field operation path obtained by the present invention for the actual application scenario. Detailed Embodiment

[0029] In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0030] The present invention conducts full-coverage path planning for convex polygon farmland and farmland with arbitrary operation orientations. The present invention divides the farmland into an in-field operation area and a cape area by using the preset information, and completes the prior path planning and generates a path file based on the operation type, operation width, turning radius of the agricultural machinery, the starting point of the agricultural machinery in the farmland, and the operation orientation.

[0031] As Figure 1 shown, a method for planning and optimizing the full-coverage operation path of agricultural machinery in a farmland scenario of the present invention includes the following steps:

[0032] Step 1: Based on the vertex coordinates of the polygonal farmland, the maximum curvature of the unmanned operation agricultural machinery itself, and the operation type, divide the farmland into an in-field operation area and a cape area (i.e., Figure 1 preprocessing of the operation area);

[0033] Step 2: Based on the operation width of the unmanned operation agricultural machinery and the operation starting point and operation orientation when entering the farmland, perform full-coverage operation strip segmentation on the in-field operation area to form the basic path of the operation strip (i.e., Figure 1 solution of the operation path);

[0034] Step 3: Determine the turning path of the cape area according to the turning radius and the starting point of the strip turning in the operation strip (i.e., Figure 1 the starting point of the strip turning), that is, Figure 1 solution of the cape turning path);

[0035] Step 4: Determine the edge-closing path of the cape area according to the basic path of the operation strip generated in Step 2 and the cape turning path determined in Step 3, so as to generate a full-coverage path of the farmland and generate a path file.

[0036] Specifically, the said Step 1 includes:

[0037] Complete the delimitation of the scope of each area according to the vertex coordinates of the polygonal farmland, the maximum curvature of the agricultural machinery turning, and the operation type. Divide the cape area towards the centroid of the convex polygon according to the operation width and maximum curvature of the agricultural machinery. The width of the cape area is as shown in formula (1):

[0038] (1)

[0039] Wherein, represents the operation width, represents the maximum curvature of the agricultural machinery turning, represents the ceiling operation, and max represents the maximum value operation.

[0040] The width of the cape area is obtained by taking the maximum value of 2 times the turning radius and the operation width, dividing by the ceiling of the operation width, and then multiplying by the operation width. The width of the cape area obtained by this scheme can not only ensure that the U-turn after the operation area of the agricultural machinery does not exceed the farmland range, but also ensure that there is no double compression during the operation in the cape area.

[0041] The present invention ensures the development of the edge-closing operation and the turning operation in the cape area through width constraints. After the width of the cape area is determined, the farmland is compressed inward to obtain the operation area, and the compression range is the cape area, as Figure 2 shown.

[0042] Specifically, the said Step 2 includes:

[0043] Construct a virtual rectangle according to the operation orientation to find the convex polygon of the operation area in the field. The two farthest points on both sides of the operation orientation are the Figure 3 in , two points, Figure 3 in is the distance between the two farthest points in the operation orientation. Combine the operation width to perform operation strip segmentation. Cut the operation area by equally dividing the AB line to solve the operation strip, ensuring full coverage of the operation in the field by unmanned agricultural machinery; to meet the requirements of full coverage operation, the distance between adjacent operation strips should be equal to the operation width, and the number of strips is , as shown in Equation (2):

[0044] (2)

[0045] where, is the maximum width of the operation area. Ensures that the operation strip realizes full coverage operation of the operation area.

[0046] Specifically, step 3 includes:

[0047] When dividing the cape area in step 1, it is ensured that the agricultural machinery will not exceed the farmland range when turning around in the cape area. Solve the turning path through the Dubins curve. The path set of the Dubins curve is {LSL, RSR, RSL, LSR, RLR, LRL}, where L represents the circular arc movement to the left, R represents the circular arc movement to the right, and S indicates the movement along a straight line. When conventionally finding the Dubins curve, the optimal route is mainly selected through the degree of radian change and the total length of the curve. When solving the Dubins turning arc of the cape turning route with the traditional optimal scheme, when the entry and exit points of two adjacent operation strips are on the same side of the operation area, the safe and smooth turning path between the operation strips can be obtained through the Dubins curve; but when the entry and exit points of two adjacent operation strips are not on the same side of the operation area, the turning path solved by the conventional Dubins optimal curve may have the risk of crushing the crops in the operation area, as Figure 4 shown, , is the Dubins turning arc.

[0048] Therefore, when evaluating the optimality of the Dubins path set, add a collision detection factor to minimize the re-compression of the strip turning path on the operation area. The optimal evaluation function of the Dubins curve can be written as Equation (3):

[0049] (3)

[0050] where, is the path cost, represents the degree of radian change, is the path length, is the number of points of the turning path in the operation area, is the total number of points on the turning path, is the weight coefficient of the radian change, is the weight coefficient of the path length, is the coefficient of the double compaction rate. After being optimized by the evaluation function of Equation (3), when the entry and exit points of two adjacent operation strips are not on the same side of the operation area and there is a risk of double compaction, the Dubins turning arc obtained is as Figure 5 shown.

[0051] Specifically, the step 4 includes:

[0052] As can be seen from Equation (4), the number of operation strips for the edge trimming of the farmland cape is . The ideal edge trimming trajectory of the cape is inner shrinking width convex polygon farmland border. Due to the curvature constraint in the steering movement of the unmanned agricultural machine, it is necessary to smooth the trajectory at the turning of the cape, as Figure 6 shown, where R is the minimum turning radius, obtained from the reciprocal of the maximum curvature of the agricultural machine steering, is the interior angle between two adjacent sides, and the minimum smoothing length at both ends of each vertex is , which can be solved by Equation (5).

[0053] (4)

[0054] (5)

[0055] By smoothing the edge trimming path in the cape area, the edge trimming operation at the cape can be completed at the cost of sacrificing a small amount of operation space in the cape area. The smoothing process of the edge trimming path in the cape area is as follows: the minimum smoothing length at both ends of each vertex is L smooth =R·tan(2α), where α is the interior angle between two adjacent sides, and R is the minimum turning radius, obtained from the reciprocal of the maximum curvature of the agricultural machine steering.

[0056] The present invention also provides an agricultural machine full-coverage operation path planning and optimization device in a farmland scenario, including the following modules:

[0057] A zoning module, which divides the farmland into an in-field operation area and a cape area based on the coordinates of each vertex of the polygonal farmland, the maximum curvature of the unmanned operation agricultural machine itself, and the operation type;

[0058] A full-coverage operation strip segmentation module, which segments the in-field operation area into full-coverage operation strips based on the operation width of the unmanned operation agricultural machine and the operation starting point and operation orientation entering the farmland, to form a basic path of the operation strip;

[0059] The turning path determination module determines the turning path in the cape area according to the turning radius and the starting point of the turning of the operation strip through an improved Dubins curve algorithm;

[0060] The full-coverage path generation module determines the edge-closing path in the cape area according to the basic path of the operation strip and the turning path in the cape area, thereby generating a full-coverage path for the farmland and generating a path file.

[0061] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, the steps of the above-mentioned method for planning and optimizing the full-coverage operation path of agricultural machinery in the farmland scenario are implemented.

[0062] The present invention also provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the above-mentioned method for planning and optimizing the full-coverage operation path of agricultural machinery in the farmland scenario are implemented.

[0063] Embodiment:

[0064] According to the method proposed by the present invention, the vertex information of the real plot in the WGS84 coordinate system of the Unmanned Farm Demonstration Base in Jiaqiao Town, Zouping City is brought in: [[571405.61,4089406.0],[571755.61,4089406.0],[571555.61,4089679.0],[571405.61,4089599.0],[571360.36,4089469.0]], the working width of the agricultural machinery-mounted implement is 5 m, the turning curvature constraint of the agricultural machinery is 0.18, and the working direction is 180° from north to south. The width of the cape area is obtained as 15 m respectively, that is, there are 3 edge-closing strips in the cape area; the number of strips in the operation area is 48, and finally the in-field operation route is obtained as Figure 7 shown. Compared with the existing methods for solving the in-field unmanned operation path, the present invention improves the coverage rate of the in-field unmanned operation and has higher applicability to the plot shape.

[0065] Those skilled in the art should understand that the embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk memories, CD-ROMs, optical memories, etc.) containing computer-usable program codes. The solutions in the embodiments of the present invention can be implemented in various computer languages, for example, object-oriented programming languages such as Java and interpreted scripting languages such as JavaScript.

[0066] The present invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It should be understood that each flow and / or block of the flowchart illustrations and / or block diagrams, and combinations of flows and / or blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions executed by the processor of the computer or other programmable data processing apparatus create means for implementing the functions specified in the flowchart flow or flows and / or block or blocks. Figure 1 in a flow or flows and / or block or blocks Figure 1 or blocks.

[0067] These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means that implement the functions specified in the flowchart flow or flows and / or block or blocks. Figure 1 in a flow or flows and / or block or blocks Figure 1 or blocks.

[0068] These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process, such that the instructions executed on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and / or block or blocks. Figure 1 in a flow or flows and / or block or blocks Figure 1 or blocks.

[0069] Although the preferred embodiments of the present invention have been described, additional changes and modifications can be made by those skilled in the art once they learn of the basic inventive concept. Therefore, the appended claims are intended to be construed to include the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0070] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. A method for path planning and optimization of full coverage operation of agricultural machinery in farmland scenarios, characterized in that, It includes the following steps: Step 1: Divide the farmland into in-field operation areas and cape areas based on the vertex coordinates of the polygonal farmland, the maximum curvature of the unmanned operation agricultural machinery itself, and the operation type; divide the cape area towards the centroid of the convex polygon according to the operation width and maximum curvature of the unmanned operation agricultural machinery. The width of the cape area is obtained by taking the maximum value of twice the turning radius and the operation width, dividing it by the operation width, rounding up, and then multiplying by the operation width to get the width of the cape area : (1) Among them, represents the working width, represents the maximum curvature of the agricultural machinery steering, represents the ceiling operation, and max represents the maximum value operation; Step 2: Based on the working width of the unmanned agricultural machinery, the starting point of operation and the operation orientation when entering the farmland, divide the in-field operation area into full-coverage operation strip segments to form the basic path of the operation strips; Construct a virtual rectangle according to the operation orientation, find the farthest points on both sides of the operation orientation of the convex polygon of the operation area in the field, combine the operation width to perform operation strip segmentation, and cut the operation area in the field by equally dividing the AB line to solve the operation strip. The spacing between adjacent operation strips is equal to the operation width, and the number of strips is as follows: (2) Among them, is the maximum width of the working area, represents the ceiling operation, represents the working width; Step 3: According to the turning radius and the starting point of the operation strip turning, determine the turning path in the cape area through the improved Dubins curve algorithm; The improved Dubins curve algorithm includes: when performing the optimal evaluation of the Dubins path set, adding a collision detection factor, and the optimized evaluation function is: (3) Among them, is the path cost, represents the degree of radian change, is the path length, is the number of points of the turning path in the operation area, is the total number of points of the turning path, is the radian change weight coefficient, is the path length weight coefficient, is the multi-rolling rate coefficient; Step 4: Determine the edge-closing path in the cape area according to the basic path of the operation strips generated in Step 2 and the turning path in the cape area determined in Step 3, thereby generating a full-coverage path of the farmland and generating a path file.

2. The method for planning and optimizing the operation path of agricultural machinery with full coverage in a farmland scenario according to claim 1, characterized in that, In the said step 4, the ideal cape trimming trajectory is a convex polygon farmland border that shrinks in width, and the minimum smooth length at both ends of each vertex of the convex polygon farmland is , solved by Equation (5): (5) Among them, is the maximum curvature of the agricultural machinery steering, is the interior angle between two adjacent sides; Smooth the trimming path of the cape area, and the minimum smoothing length at both ends of each vertex is L smooth =R·tan(2α), where α is the interior angle between two adjacent sides, and R is the minimum turning radius, which is obtained by taking the reciprocal of the maximum curvature of the agricultural machinery steering obtained.

3. The method for planning and optimizing the operation path of agricultural machinery with full coverage in a farmland scenario according to claim 1, characterized in that, The polygonal farmland is a convex polygonal farmland.

4. A method for planning and optimizing the operation path of full coverage of agricultural machinery in a farmland scenario according to claim 1, characterized in that, The operation types include sowing and spraying.

5. An agricultural machinery full-coverage operation path planning and optimization device in a farmland scenario, characterized in that, A method for implementing any one of claims 1-4 includes the following modules: A zoning module, which divides the farmland into an in-field operation area and a cape area based on the coordinates of each vertex of the polygonal farmland, the maximum curvature of the unmanned agricultural machinery itself, and the operation type; A full-coverage operation strip segmentation module, which divides the in-field operation area into full-coverage operation strip segments based on the working width of the unmanned agricultural machinery, the starting point of operation and the operation orientation when entering the farmland to form the basic path of the operation strips; A turning path determination module, which determines the turning path in the cape area through the improved Dubins curve algorithm according to the turning radius and the starting point of the operation strip turning; A full-coverage path generation module, which determines the edge-closing path in the cape area according to the basic path of the operation strips and the turning path in the cape area, thereby generating a full-coverage path of the farmland and generating a path file.

6. An electronic device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that When the processor executes the program, it implements the steps of the method for planning and optimizing the full-coverage operation path of agricultural machinery in the farmland scenario described in any one of claims 1-4.

7. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the method for planning and optimizing the full-coverage operation path of agricultural machinery in the farmland scenario described in any one of claims 1-4.

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