Bionic convex hull structure, design method of rotary blade, rotary blade and rotary cultivator

Abstract

The invention discloses a bionic convex hull structure, a design method of a rotary blade, the rotary blade and a rotary cultivator, the bionic convex hull structure is obtained by simulating pangolin scales, the forward contour of the bionic convex hull structure is defined by a first parabola and a second parabola which are intersected at two points, and the cross section contour is defined by a first arc based on a first radius; according to the embodiment of the invention, the head-on structure is synergistically bionic through the first parabola and the straight line, and the horizontal component of the normal counter force on the head-on structure is reduced through the smooth gradient of the head-on structure, so that the forward impact of soil on the head-on structure is reduced, and the stability of the head-on structure is improved. And the back surface structure is synergistically bionic through the second parabola and the second arc, and the steep slope of the back surface structure reduces the contact area between the back surface structure and the soil, so that the attachment points of the soil on the back surface structure are reduced, and the anti-sticking requirement of the wet and sticky soil in the farming environment is met from the two dimensions of mechanical buffering and contact soil removal.

Description

Technical Field

[0001] This invention relates to the field of agricultural machinery tillage, and in particular to a biomimetic convex hull structure, a design method for rotary tillers, rotary tillers, and a rotary tiller. Background Technology

[0002] Soil tillage is one of the most important technologies in agricultural production, directly affecting soil looseness, water and fertilizer retention capacity, and crop growth environment.

[0003] During cultivation, soil contact components are susceptible to resistance effects such as soil adhesion and particle blockage. This is especially true in wet and sticky rice stubble fields under rice-wheat rotation systems, where the soil moisture content is high and the content of colloidal components is rich, resulting in a significant increase in soil viscosity. Consequently, the cultivation efficiency and quality of soil contact components under these soil conditions tend to deteriorate.

[0004] Traditional soil-contact components often employ regular convex structures such as circles or pyramids. Their contact surface with the soil exhibits a single geometric feature, easily forming a continuous adhesion layer on the contact surface. This makes it difficult to meet the anti-sticking requirements of wet, sticky soil cultivation environments. Summary of the Invention

[0005] This invention provides a biomimetic convex hull structure, a design method for rotary tillers, rotary tillers, and a rotary tiller to solve the problem that regular convex hull structures cannot meet anti-adhesion requirements, thereby improving anti-adhesion stability and smoothness during soil contact operations.

[0006] According to one embodiment of the present invention, a biomimetic convex hull structure is provided, which is biomimeticly derived from pangolin scales;

[0007] The forward profile of the biomimetic convex hull structure is defined by a first parabola and a second parabola intersecting at two points, the cross-sectional profile is defined by a first circular arc based on a first radius, and the longitudinal profile is defined by a straight line intersecting at one point and a second circular arc based on a second radius, wherein the first radius is greater than the second radius.

[0008] According to another embodiment of the present invention, a method for designing rotary tillers is provided, the method comprising:

[0009] The contour image of pangolin scales is collected, the contour image is subjected to coordinate extraction to obtain contour coordinate data, and the contour coordinate data is subjected to curve fitting to obtain a convex hull structure model, the convex hull structure model corresponding to the biomimetic convex hull structure described in any embodiment of the present invention;

[0010] Based on the matrix structure data of the rotary tiller blades, a matrix structure model was constructed;

[0011] On the base structure model, multiple convex hull structure models are arranged in an array according to the convex hull arrangement to obtain the rotary tillage blade working model, so as to complete the design of the rotary tillage blade;

[0012] In the biomimetic convex hull structure, the first parabola and straight line biomimetic facing structure are oriented towards the rotary cutting direction of the rotary tiller.

[0013] According to another embodiment of the present invention, a rotary tiller is provided, comprising: a handle and a blade connected to the handle, the blade being a trapezoidal straight blade, including a front tangent along the rotary cutting direction, a side tangent perpendicular to the rotary cutting direction, and a blade head disposed away from the handle, the blade being curved toward the side tangent;

[0014] The surface of the blade is arranged with multiple biomimetic convex structures, which are biomimetic to pangolin scales. The rotary tiller is obtained by the rotary tiller design method as described in any embodiment of the present invention.

[0015] According to another embodiment of the present invention, a rotary tiller is provided, comprising: a rotary tiller blade assembly, wherein at least one rotary tiller blade as described in any embodiment of the present invention is disposed on the rotary tiller blade assembly.

[0016] The technical solution of this invention utilizes the surface features of pangolin scales to design a biomimetic convex hull structure. The frontal structure, biomimetic with a first parabola and a straight line, has a gentle slope that reduces the horizontal component of the normal reaction force on the frontal structure, thereby reducing the positive impact of the soil on the frontal structure. The back structure, biomimetic with a second parabola and a second circular arc, has a steep slope that reduces the contact area between the back structure and the soil, thereby reducing the number of soil attachment points on the back structure. This heterogeneous convex hull structure disrupts the continuity of soil adhesion, solving the problem that regular convex hull structures cannot meet anti-adhesion requirements. It reduces soil adhesion resistance from both mechanical buffering and contact soil removal dimensions, thereby improving the anti-adhesion stability and smoothness during soil contact operations.

[0017] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1This is a schematic diagram of the outline of a biomimetic convex hull structure provided in one embodiment of the present invention;

[0020] Figure 2 This is a schematic diagram of the fitting of the positive contour of a biomimetic convex hull structure provided in one embodiment of the present invention;

[0021] Figure 3 This is a schematic diagram of the fitting of the cross-sectional profile of a biomimetic convex hull structure provided in one embodiment of the present invention;

[0022] Figure 4 This is a schematic diagram of the fitting of the longitudinal section profile of a biomimetic convex hull structure provided in one embodiment of the present invention;

[0023] Figure 5 A flowchart illustrating a design method for a rotary tiller blade provided in one embodiment of the present invention;

[0024] Figure 6 This is a frontal image of pangolin scales acquired using scanning electron microscopy, as provided in one embodiment of the present invention.

[0025] Figure 7 A schematic diagram illustrating a specific example of a matrix structure model provided in an embodiment of the present invention;

[0026] Figure 8 This is a schematic diagram of a convex hull arrangement array provided in one embodiment of the present invention;

[0027] Figure 9 This is a schematic view of a rotary tiller operation model provided in one embodiment of the present invention;

[0028] Figure 10 A flowchart illustrating another design method for rotary tillers provided in one embodiment of the present invention;

[0029] Figure 11 This is a schematic diagram of a discrete element model provided in one embodiment of the present invention;

[0030] Figure 12 This is a schematic diagram of a cutting simulation using a discrete element model, provided in one embodiment of the present invention.

[0031] Figure 13 This is a schematic diagram of the contact area of ​​the lateral tangential resistance of a blade during rotary tillage under different working conditions, provided as an embodiment of the present invention.

[0032] Figure 14 A flowchart illustrating a specific example of a rotary tillage blade design method provided in an embodiment of the present invention;

[0033] Figure 15This is a schematic diagram of the structure of a rotary tiller provided in one embodiment of the present invention. Detailed Implementation

[0034] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0035] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0036] Figure 1 This is a schematic diagram of the outline of a biomimetic convex hull structure according to an embodiment of the present invention. In this embodiment, the biomimetic convex hull structure is biomimetic to pangolin scales. The forward outline of the biomimetic convex hull structure is defined by a first parabola and a second parabola intersecting at two points. The cross-sectional outline is defined by a first circular arc based on a first radius. The longitudinal section outline is defined by a straight line intersecting at one point and a second circular arc based on a second radius, wherein the first radius is larger than the second radius.

[0037] like Figure 1 As shown, Figure 1 -a represents the positive contour of the biomimetic convex hull structure, L1 represents the first parabola, L2 represents the second parabola, and points A and B represent the two intersection points of the first parabola L1 and the second parabola L2. Figure 1 In the -b parameter, the solid curve represents the cross-sectional profile of the biomimetic convex hull structure, L3 represents the first circular arc, and the perpendicular distance from the vertex of the solid curve to the dashed line represents the thickness information of the pangolin scales. The dot represents the point corresponding to the first arc. Indicates the first radius. Figure 1 The solid curve in -c represents the longitudinal profile of the biomimetic convex hull structure, L4 represents the straight line, L5 represents the second circular arc, and point C represents the intersection of the straight line and the second circular arc. The dot represents the point corresponding to the second arc. The second radius is indicated by the vertical distance from point C to the dashed line, which represents the thickness of the pangolin scales.

[0038] This embodiment and the following embodiments use the length information corresponding to the major axis of pangolin scales and the width information corresponding to the minor axis of pangolin scales as examples for illustration.

[0039] Specifically, the first vertex perpendicular distance of the first parabola and the second vertex perpendicular distance of the second parabola are associated with the length information of the pangolin scales, the first radius is associated with the width and thickness information of the pangolin scales, and the second radius is associated with the second vertex perpendicular distance and the thickness information of the pangolin scales.

[0040] exist Figure 1 In -a, the first vertex perpendicular distance represents the perpendicular distance from the vertex coordinates of the first parabola to the straight line containing points A and B, the second vertex perpendicular distance represents the perpendicular distance from the vertex coordinates of the second parabola to the straight line containing points A and B, and the straight-line distance between points A and B represents the width information of the pangolin scales.

[0041] In one specific embodiment, the contour of the biomimetic convex hull structure is obtained by fitting the contour coordinate data of the pangolin scales. The contour coordinate data is obtained by extracting the coordinates of the contour image of the pangolin scales in a preset three-dimensional coordinate system. The contour image includes a frontal image, a cross-sectional image, and a longitudinal cross-sectional image.

[0042] The preset three-dimensional coordinate system refers to a three-dimensional spatial reference system pre-set for uniformly extracting the coordinate information of pangolin scales. It includes three mutually perpendicular coordinate axes: the horizontal coordinate axis, the vertical coordinate axis, and the vertical coordinate axis. The horizontal coordinate axis, the vertical coordinate axis, and the vertical coordinate axis are denoted as the X-axis, the Y-axis, and the Z-axis, respectively. Here, there are no restrictions on the reference point of the preset three-dimensional coordinate system or the correspondence between the three coordinate axes and the length, width, and thickness directions of the pangolin scales.

[0043] Specifically, the contour image is used to present the geometric boundaries of the outer surface of the pangolin scales, containing edge morphology information of the pangolin scales. The frontal image represents the image acquired along the thickness direction of the pangolin scales, the cross-sectional image represents the image acquired along the length direction of the pangolin scales, and the longitudinal cross-sectional image represents the image acquired along the width direction of the pangolin scales.

[0044] Specifically, the contour coordinate data includes, in a preset three-dimensional coordinate system, the forward coordinate data corresponding to the forward image, the cross-sectional coordinate data corresponding to the cross-sectional image, and the longitudinal cross-sectional coordinate data corresponding to the longitudinal cross-sectional image.

[0045] The technical solution of this embodiment utilizes the surface features of pangolin scales to design a biomimetic convex hull structure. The frontal structure, which is biomimetic through the coordinated use of a first parabola and a straight line, has a gentle slope that reduces the horizontal component of the normal reaction force on the frontal structure, thereby reducing the positive impact of the soil on the frontal structure. The back structure, which is biomimetic through the coordinated use of a second parabola and a second circular arc, has a steep slope that reduces the contact area between the back structure and the soil, thereby reducing the number of soil attachment points on the back structure. The heterogeneous convex hull structure disrupts the continuity of soil adhesion, solving the problem that regular convex hull structures cannot meet the anti-adhesion requirements. It reduces the soil adhesion resistance from both mechanical buffering and contact soil removal dimensions, thereby improving the anti-adhesion stability and smoothness during soil contact operations.

[0046] Based on the above embodiments, optionally, the reference point of the preset three-dimensional coordinate system represents the geometric center point of the pangolin scales.

[0047] In one optional embodiment, the reference point is the intersection of the longest horizontal axis and the longest vertical axis of the pangolin scale, or the reference point is the intersection of the longest horizontal axis and the longest vertical axis of the pangolin scale, or the reference point is the intersection of the longest vertical axis and the longest longitudinal axis of the pangolin scale.

[0048] In one specific embodiment, when the reference point is the intersection of the longest horizontal axis and the longest vertical axis of the pangolin scale, the horizontal coordinate axis is along the width direction of the pangolin scale, the vertical coordinate axis is along the length direction of the pangolin scale, and the vertical coordinate axis is along the thickness direction of the pangolin scale.

[0049] For example, the horizontal axis represents the distance from the left end to the right end of the pangolin scale, the vertical axis represents the distance from the rear end to the front end of the pangolin scale, and the vertical coordinate axis represents the distance from the inner surface to the outer surface of the pangolin scale.

[0050] In this embodiment, the positive contour of the biomimetic convex hull structure satisfies the following fitting equation:

[0051] ;

[0052] The cross-sectional profile of the biomimetic convex hull structure satisfies the following fitting equation:

[0053] ;

[0054] The longitudinal section profile of the biomimetic convex hull structure satisfies the following fitting equation:

[0055] ;

[0056] in, This represents the perpendicular distance from the vertex of the first parabola. This represents the perpendicular distance from the vertex of the second parabola. This indicates the length of the pangolin scales. , This represents half the width of the pangolin scales. Indicates the first radius. This indicates the height of the pangolin scales. This represents the second radius.

[0057] Figures 2-4 The following are schematic diagrams showing the fitting of the forward profile, cross-sectional profile, and longitudinal profile of the biomimetic convex hull structure corresponding to the three sets of fitting equations.

[0058] The technical solution of this embodiment constructs a preset three-dimensional coordinate system with the geometric center point of the pangolin scale as the reference point, so that some coordinate information in the contour coordinate data presents a centrally symmetrical distribution, thereby simplifying the computational workload of biomimetic modeling of the biomimetic convex hull structure. At the same time, the contour coordinate data are all based on the shape of the pangolin scale itself as the reference, which avoids the systematic offset caused by the origin offset compared to relying on external random reference points, and provides more accurate coordinate support for biomimetic modeling of the biomimetic convex hull structure.

[0059] Figure 5 This is a flowchart illustrating a design method for a rotary tiller blade according to one embodiment of the present invention. This embodiment is applicable to the biomimetic design of non-smooth surface structures of rotary tiller blades, such as... Figure 5 As shown, the method includes:

[0060] S110. Collect the contour image of pangolin scales, extract the contour coordinates from the contour image to obtain contour coordinate data, and perform curve fitting based on the contour coordinate data to obtain a convex hull structure model.

[0061] Specifically, the contour image is used to represent the geometric boundaries of the outer surface of pangolin scales, containing edge morphology information of the pangolin scales. The contour image includes a frontal image, a cross-sectional image, and a longitudinal cross-sectional image. The frontal image represents the image acquired along the thickness direction of the pangolin scales, the cross-sectional image represents the image acquired along the length direction of the pangolin scales, and the longitudinal cross-sectional image represents the image acquired along the width direction of the pangolin scales.

[0062] For example, contour images can be obtained using scanning electron microscopy, optical microscopy, or high-resolution cameras, but are not limited to the examples given. Figure 6 This is a frontal image of pangolin scales acquired using scanning electron microscopy, as provided in one embodiment of the present invention.

[0063] In one example, a complete pangolin scale was selected, and surface stains were wiped off with anhydrous ethanol. The dried pangolin scale was then fixed on the sample stage of a scanning electron microscope (SEM), with a scanning step size of 1 μm set to ensure that the edge details of the pangolin scale were clearly discernible. Using the SEM imaging system, frontal, cross-sectional, and longitudinal cross-sectional images were captured along the thickness, length, and width directions of the pangolin scale, respectively. The contour images were preprocessed using the SEM's accompanying analysis software, including grayscale enhancement and noise reduction, and then saved as editable TIFF image files.

[0064] Specifically, the contour coordinate data includes, in a preset three-dimensional coordinate system, the forward coordinate data corresponding to the forward image, the cross-sectional coordinate data corresponding to the cross-sectional image, and the longitudinal cross-sectional coordinate data corresponding to the longitudinal cross-sectional image.

[0065] In one alternative embodiment, the reference point of the preset three-dimensional coordinate system represents the geometric center point of the pangolin scales.

[0066] In one optional embodiment, extracting contour coordinates from the contour image to obtain contour coordinate data includes: extracting contours from the contour image to obtain continuous contour lines, mapping the continuous contour lines to a preset three-dimensional coordinate system, and reading the coordinates on the continuous contour lines at preset intervals to obtain contour coordinate data, so as to ensure complete coverage of the contour lines.

[0067] Based on the above embodiments, optionally, before obtaining the convex hull structure model by curve fitting based on the contour coordinate data, the method further includes: performing curvature analysis on the continuous contour lines to obtain key contour points, and adding the coordinate information of the key contour points in a preset three-dimensional coordinate system to the contour coordinate data. For example, the key contour points can be start points, end points, or curvature extrema, etc., providing high-density data support for the fitting design of the biomimetic convex hull structure.

[0068] In one example, the contour image is imported into CAD software. Using the coordinate system definition and coordinate reading functions of the CAD software, the coordinate information of the contour points in the preset three-dimensional coordinate system is recorded evenly at 1mm intervals, as well as the coordinate information of the key contour points in the preset three-dimensional coordinate system. The recorded coordinate information is then organized into contour coordinate data stored in Excel format.

[0069] Based on the above embodiments, optionally, before obtaining the convex hull structure model by curve fitting based on the contour coordinate data, the method further includes: performing error verification processing on the contour coordinate data. Specifically, through data alignment technology, the contour coordinate data is geometrically aligned with the continuous contour line. For each contour point, the minimum distance between the contour point and the continuous contour line is determined. When the minimum distance is greater than the distance error threshold, the coordinate information of the contour point is corrected.

[0070] The advantage of this setup is that it provides high-precision data support for the fitting design of biomimetic convex hull structures.

[0071] Specifically, curve fitting is performed based on the contour coordinate data to obtain the fitting equations corresponding to the forward contour, cross-sectional contour, and longitudinal contour of the biomimetic convex hull structure, respectively. The convex hull structure model is obtained by modeling based on the three sets of fitting equations. In this embodiment, the convex hull structure model corresponds to the biomimetic convex hull structure described in any embodiment of the present invention.

[0072] In one example, the contour coordinate data is imported into Origin software, and combined with the smoothing features of the biomimetic convex hull structure, curve fitting is performed based on the contour coordinate data to obtain three sets of fitting equations.

[0073] S120. Construct a matrix structure model based on the matrix structure data of the rotary tiller blade.

[0074] Among them, the matrix structure data represents the core geometric and physical parameters of the rotary tiller blade, including but not limited to key data such as blade length, width, thickness, cutting edge angle, bending angle, mounting hole size, material density and strength, which are the basis for constructing the matrix structure model.

[0075] Specifically, the matrix structure data is associated with the rotary tillage conditions to which the rotary tiller blades belong. For example, under the sowing agronomic conditions, the rotary tiller blades are shorter in length and moderate in thickness to ensure even shallow tillage and avoid damaging the seedbed; under the field clearing agronomic conditions, the rotary tiller blades are thicker and longer in length to increase soil penetration; under the straw return to the field conditions, the rotary tiller blades have more mounting holes and a wider blade to improve the straw crushing effect.

[0076] Figure 7 This is a schematic diagram illustrating a specific example of a substrate structure model provided in an embodiment of the present invention. In SolidWorks software, based on the agronomical requirements for wheat sowing, the rotary tiller blade is a trapezoidal straight blade with a short side of 42mm, a long side of 106mm, a cutting edge angle of 90°, a blade thickness of 10mm, a bending angle of the blade relative to the lateral cutting surface of the handle of 20°, an angle of 15° between the bevel of the blade and the side of the handle, and two mounting holes on the handle.

[0077] S130. On the base structure model, multiple convex hull structure models are arranged in a convex hull array to obtain a rotary tiller working model, so as to complete the design of the rotary tiller.

[0078] Among them, the convex hull arrangement array represents the array form of non-overlapping ordered distribution of biomimetic convex hull structures.

[0079] Figure 8 This is a schematic diagram of a convex hull arrangement array provided in one embodiment of the present invention, as shown below. Figure 8 As shown, Figure 8 -a、 Figure 8 -b and Figure 8 -c represents rectangular, rhomboid, and arithmetic sequence arrays, respectively. The circle represents the biomimetic convex hull structure. A rectangular array indicates that the biomimetic convex hull structures in both rows and columns are equally spaced. A rhomboid array indicates that the biomimetic convex hull structures in adjacent columns are staggered, while those in the same row are equally spaced. An arithmetic sequence array indicates that the spacing between the biomimetic convex hull structures in adjacent columns varies according to an arithmetic sequence, while the spacing between adjacent rows remains consistent and constant. Figure 8 In the diagram, lx represents the spacing between adjacent columns, ly represents the spacing between adjacent rows, and l represents the distance between the boundary of the rectangular space of the biomimetic convex hull structure and the boundary of the rotary tiller blade.

[0080] In one alternative embodiment, the convex hull arrangement array is a rhomboid arrangement array.

[0081] In this embodiment, the first parabola and straight line in the biomimetic convex hull structure are biomimeticly aligned with the rotary cutting direction of the rotary tiller.

[0082] Based on the above embodiments, the method may optionally further include: preparing measuring disks corresponding to at least two preset arrangement arrays according to the convex hull structure model, and selecting wet clay soil as soil samples; for each measuring disk, horizontally pressing the measuring disk into the soil sample, leaving it stationary for a preset time, and then uniformly and vertically lifting the measuring disk to obtain the tensile force value during the lifting process; after replacing the soil sample, repeating the pressing and lifting operations, and statistically analyzing multiple tensile force values ​​to obtain a standard tensile force value; and using the preset arrangement array corresponding to the smallest standard tensile force value as the convex hull arrangement array of the biomimetic convex hull structure.

[0083] Specifically, the measuring plate is equipped with a biomimetic convex hull structure based on a preset array arrangement. For example, the preset duration can be 30 seconds, the number of repetitions can be 5 times, the tension value during the lifting process can be the maximum tension value or the minimum tension value, and the standard tension value can represent the maximum value, minimum value, average value or median value, etc., but is not limited to the example given above.

[0084] In one specific embodiment, the array types corresponding to the multiple preset arrangement arrays are different, or when the multiple preset arrangement arrays are all rhomboid arrangement arrays, the preset angles and / or convex hull spacings corresponding to the multiple preset arrangement arrays are different. The preset angle represents the acute angle formed by the lines connecting the geometric center point of the staggered bionic convex hull structure to the geometric center point of the corresponding bionic convex hull structure in its adjacent array, and the convex hull spacing represents the spacing information between two adjacent bionic convex hull structures located in the same array.

[0085] In one example, wet clay soil from a rice-wheat rotation area was selected as the soil sample. An electronic universal testing machine (model DR-503A) with a range of 10000N and a testing accuracy of 0.1N was used. Different preset array arrangements of measuring discs were horizontally pressed into the soil sample, left to stand for 30 minutes, and then lifted vertically at a uniform speed. The maximum tensile force during the lifting process was recorded. Each measuring disc underwent five repeated tests, with the soil sample replaced before each test. In this example, three preset array arrangements were tested: rectangular, rhomboid, and arithmetic progression. The standard tensile force values ​​for the rectangular, rhomboid, and arithmetic progression arrays were 7.11N, 6.96N, and 7.25N, respectively. Therefore, in this example, the convex hull arrangement of the biomimetic convex hull structure was a rhomboid arrangement.

[0086] by Figure 7 Taking the shown substrate structure model as an example, combining the geometric and physical information of the substrate structure model, the scaling ratio of the convex hull structure model is selected so that the biomimetic convex hull structure is distributed on the surface of the rotary tiller according to the convex hull arrangement array. For example, in the rotary tiller working model, the height h of the biomimetic convex hull structure is 2mm, the mapping length b of the frontal structure defined by the first parabola and the straight line is 9.6mm, the mapping length d of the back structure defined by the second parabola and the second circular arc is 3.6mm, and the width of the biomimetic convex hull structure... It is 12mm.

[0087] Figure 9 This is a schematic view of a rotary tiller operating model provided in one embodiment of the present invention, as shown below. Figure 9 As shown, Figure 9 -a indicates a front view of the rotary tiller operation model. Figure 9 -b indicates a longitudinal section view of the rotary tiller working model.

[0088] Specifically, taking into account the motion characteristics of the rotary tiller, with the origin of the biomimetic convex hull structure as the center point, the biomimetic convex hull structure is arranged in a rhomboid array on the surface of the rotary tiller according to a preset angle and convex hull spacing along the rotary cutting direction of the rotary tiller.

[0089] For example, the preset angle can be 60°, forming a rhomboid grid with equilateral triangles as basic units on the surface of the rotary tiller, and the convex hull spacing can be 16mm, but it is not limited to the given example.

[0090] The technical solution of this embodiment utilizes the surface characteristics of pangolin scales to design a biomimetic convex hull structure. Based on the biomimetic convex hull structure, a non-smooth surface structure is designed for the rotary tiller blade. The non-smooth surface structure can reduce the contact area between the soil and the rotary tiller blade. Under the synergistic effect of the mechanical buffering effect and the contact soil removal effect of the biomimetic convex hull structure, the rotary tiller blade has a high level of anti-sticking performance, which improves the tillage efficiency and tillage quality of the rotary tiller blade, and reduces the energy consumption of the rotary tiller blade during operation. Its advantages are particularly significant under wet and sticky soil conditions.

[0091] Figure 10 This is a flowchart illustrating another design method for rotary tillers according to an embodiment of the present invention. This embodiment further refines the design method for rotary tillers described in the above embodiment. Figure 10 As shown, the method includes:

[0092] S210. Collect contour images of pangolin scales, extract coordinates from the contour images to obtain contour coordinate data, and perform curve fitting based on the contour coordinate data to obtain a convex hull structure model.

[0093] S220. Construct a matrix structure model based on the matrix structure data of the rotary tiller blade.

[0094] S230. On the base structure model, multiple convex hull structure models are arranged in a convex hull array to obtain a rotary tiller working model, so as to complete the design of the rotary tiller.

[0095] S210-S230 in this embodiment are the same as those in the above embodiments. Figure 5 The S110-S130 are the same or similar, and will not be described again in this embodiment.

[0096] S240. The rotary tillage blade operation model is divided into a mesh to obtain a discrete element model. The discrete element model is then applied to the soil particle model to perform cutting simulation and obtain rotary tillage performance indicators.

[0097] In one alternative embodiment, the size of the mesh element corresponding to the convex hull structure model is smaller than the size of the mesh element corresponding to the base structure model, so as to preserve the morphological and structural characteristics of the biomimetic convex hull structure during cutting simulation.

[0098] Figure 11This is a schematic diagram of a discrete element model provided in an embodiment of the present invention. The rotary tillage blade operation model is meshed using Workbenchmesh software. The basic size of the mesh element corresponding to the base structure model is 2mm, and the basic size of the mesh element corresponding to the convex hull structure model is 1mm.

[0099] Specifically, the soil particle model is an abstract technical model that characterizes the morphology, gradation, spatial distribution and interaction of soil particles, and is used to quantify the physical and mechanical properties of soil particles.

[0100] Figure 12 This is a schematic diagram of a cutting simulation using a discrete element model according to an embodiment of the present invention, as shown below. Figure 12 As shown, Figure 12 -a indicates a soil-tool coupling simulation system, in which the tools consist of a cutter shaft and multiple rotary tillage blades. Indicates the spindle speed. The speed of the cutter shaft is represented by the discrete element analysis software EDEM2024. A tillage area with a length, width and height of 1000mm×400mm×200mm is established, and soil particles with a diameter of 6mm are generated, totaling 125,000 soil particles. Figure 12 -b indicates soil particle bonding, which represents the forces between soil particles, such as adsorption, mechanical interlocking, and cementation. Soil particle bonding can be used to quantify the bonding strength, spatial distribution, and failure characteristics between soil particles.

[0101] Table 1 is a simulation example of soil and cutting tool calibrated during a cutting simulation process provided by an embodiment of the present invention.

[0102] Table 1

[0103]

[0104] In the example shown in Table 2, the Hertz-Mindlin with JKR model is used as the contact model for cutting simulation. The number of rotary tillers on the cutter shaft is set to 6, the cutter shaft forward speed is 0.8 m / s, the cutter shaft rotation speed is 200 r / min, the tillage depth is 120 mm, the single simulation run is 2 s, the data saving interval is 0.002 s, and the fixed time step is set to 8% of the Rayleigh time step to ensure the reliability of the cutting simulation.

[0105] Among them, the Hertz-Mindlin with JKR model is a cohesive contact model that considers the adhesion and hysteresis effects between soil particles. It uses surface energy parameters to equivalently characterize the bonding effect between soil particles and can also reproduce the dynamic changes of soil particles due to adhesion behavior as the cutting tool moves and falls off during the cutting simulation process.

[0106] In this embodiment, the rotary tillage performance index specifically characterizes the quantitative parameters of soil treatment by the rotary tillage operation of the blades. For example, the rotary tillage performance index includes soil disturbance index, operation efficiency index, and tillage resistance index, such as soil disturbance index including soil loosening uniformity and tillage layer depth compliance rate, operation efficiency index including operation time per unit area and total operation time, and tillage resistance index including rotary tillage torque and specific energy consumption, but is not limited to the given example.

[0107] In an optional embodiment, when the cutting simulation corresponds to the sowing agronomic conditions, the rotary tillage performance indicators include the rotary tillage resistance index and particle breakage characteristics. The rotary tillage resistance index represents the resistance force exerted by the soil on the rotary tillage blades when they interact with the soil, reflecting the energy consumption and equipment load. The particle breakage characteristics represent the particle size distribution and degree of breakage of soil particles after they are broken apart when the rotary tillage blades interact with the soil, used to describe the rationality of the soil structure after tillage operations.

[0108] For example, rotary tillage resistance indicators include average resistance value and resistance fluctuation range, while particle breakage characteristics include the proportion of soil particles with a diameter ≤5mm, the coefficient of variation of disturbance kinetic energy, the average disturbance kinetic energy per unit volume of soil, and the seedbed flatness error, but are not limited to the given examples.

[0109] In one optional embodiment, the rotary tillage resistance index is the rotary tillage torque, and / or, the particle breakage characteristic is the number of bonding bonds broken. Specifically, the smaller the rotary tillage torque, the smaller the soil adhesion and friction resistance experienced by the blade, i.e., the better the blade's anti-adhesion and drag reduction performance; the greater the number of bonding bonds broken, the more significant the blade's soil breaking effect.

[0110] In another optional embodiment, under sowing agronomic conditions, the rotary tillage performance indicators include rotary tillage resistance indicators and soil disturbance indicators. The soil disturbance indicators include the coefficient of variation of disturbance kinetic energy and seedbed flatness error. The advantage of this setting is that it can solve the problems of missed tillage and soil mounding caused by soil adhesion, provide a high-quality seedbed foundation for precision sowing, and ensure the consistency of subsequent seedling emergence rate and crop growth.

[0111] S250. Based on the rotary tillage performance indicators, the rotary tillage blade operation model is simulated and optimized until the rotary tillage performance indicators meet the rotary tillage working conditions to obtain the final rotary tillage blade operation model, thereby completing the design of the rotary tillage blade.

[0112] In this embodiment, the optimization variable information in the simulation optimization process is associated with the contact area between the biomimetic convex hull structure and the soil.

[0113] In cohesive soil environments, the soil-tool interface behavior consists of adhesion and friction, which together hinder the tangential motion of the tool. The lateral tangential resistance acting on the side surface of the rotary tiller blade comprises both frictional and adhesive components. For example, the lateral tangential resistance of the tool during rotary tillage soil breaking operations... Satisfy the following formula:

[0114]

[0115] in, The coefficient of friction represents the friction coefficient generated by the friction mechanism. This represents the adhesion coefficient resulting from the adhesion mechanism. This represents the force perpendicular to the interface, i.e., normal force. This represents the normal adhesive force at the interface. This represents the tangential adhesion force at the interface.

[0116] Taking a hemispherical convex hull as an example, the contact between the soil and the convex hull is approximately equivalent to a spherical cap-shaped contact. Taking the uniform motion of the cutting tool as an example, the lateral tangential resistance of the convex hull on the cutting tool... It can be represented as:

[0117]

[0118] in, This represents the weight of the soil. Represents the surface tension coefficient. Indicates the contact angle. Represents the radius of the convex hull. This indicates the height at which the soil contacts the convex hull.

[0119] Figure 13 This is a schematic diagram of the contact area of ​​the lateral tangential resistance of the blade during rotary tillage under different working conditions, provided as an embodiment of the present invention. The slanted area at the top of the convex bulge represents the contact area between the soil and the convex bulge.

[0120] like Figure 13 As shown, compared to Figure 13 -a initial operating condition, Figure 13 The radius of the convex hull in -b is from Increase to , Figure 13 The tool axis feed rate in -c is from Reduce to as well as Figure 13 The convex hull spacing in -d is from Increase to All of these factors contribute to a synchronous increase in the surface tension coefficient and the contact height between the soil and the convex hull, indicating a strong correlation between the convex hull size, the cutter shaft forward speed, the convex hull spacing, and the contact area between the soil and the convex hull.

[0121] In one optional embodiment, the optimization variable information includes at least one of the following: the width of the biomimetic convex hull structure, the spacing between the convex hulls, and the rotational speed of the rotary tiller shaft, to achieve the optimal design of the rotary tiller working model. Specifically, optimizing the convex hull width can reduce the local adhesion strength of the soil to the biomimetic convex hull structure; optimizing the convex hull spacing can balance the soil load distribution on the rotary tiller surface; and optimizing the rotary tiller rotational speed can shorten the residence time of soil on the rotary tiller surface.

[0122] For example, the optimization schemes used in the simulation optimization process include genetic optimization schemes, Bayesian optimization schemes, or particle swarm optimization schemes, but are not limited to the given examples.

[0123] In an optional embodiment, when the optimization variable information includes three optimization variables, the optimization scheme adopted in the simulation optimization process is a three-factor, three-level regression scheme.

[0124] Table 2 shows an example of the parameters for the test level and optimization variable in a three-factor, three-level regression scheme provided in an embodiment of the present invention.

[0125] Table 2

[0126]

[0127] Figure 14 The flowchart illustrates a specific example of a rotary tiller blade design method provided in an embodiment of the present invention. In this embodiment, the rotary tiller blade design method includes steps such as selecting pangolin scales, designing a biomimetic convex hull structure, designing a convex hull array, dynamic analysis, designing a rotary tiller blade working model, and EDEM (Engineering Discrete Element Method) simulation.

[0128] Specifically, a complete pangolin scale is selected. In the design steps of the biomimetic convex hull structure, reverse engineering technology is used to acquire the contour image of the pangolin scale through a scanning electron microscope. The contour image is then subjected to coordinate extraction in a preset coordinate system to obtain contour coordinate data. Based on the contour coordinate data, curve fitting is performed to obtain the contour fitting equation of the biomimetic convex hull structure, thereby completing the design of the biomimetic convex hull structure.

[0129] In the design step of the convex hull array, various preset array configurations of measuring disks are prepared. Adhesion forces of different preset array configurations are measured through pull-out interface tests, thus completing the design of the convex hull array. In the dynamic analysis step, the interface behavior of the soil and the cutting tool is dynamically analyzed in a cohesive soil environment. Variables affecting the contact area between the soil and the convex hull are used as optimization variables in the simulation optimization process.

[0130] In the design steps of the rotary tiller blade operation model, the base structure model of the rotary tiller blade is obtained by modeling the base structure data of the defined trapezoidal straight blade body. The convex hull structure model of the biomimetic convex hull structure is obtained by modeling the contour fitting equation obtained in the design steps of the biomimetic convex hull structure. The convex hull arrangement array obtained in the design steps of the convex hull arrangement array is used to arrange multiple convex hull structure models on the base structure model to obtain the rotary tiller blade operation model.

[0131] In the EDEM simulation step, the rotary tiller operation model is meshed to obtain a discrete element model. The discrete element model is then applied to the soil particle model for cutting simulation, and a soil-tiller coupled simulation system is built. Tillage resistance and soil disturbance are selected as rotary tillage performance indicators. Using the Box-Behnken Design (BBD) optimization strategy, a mathematical approximation model of the optimization variables and rotary tillage performance indicators is established. By balancing the comprehensive characteristics of tillage resistance and soil disturbance, the optimal parameter combination is selected to design the rotary tiller operation model, thus completing the design of the rotary tiller.

[0132] The technical solution of this embodiment takes the contact area between the biomimetic convex hull structure and the soil as the starting point for simulation optimization. Through simulation iteration verification, the working characteristics of the rotary tiller blade acting on the soil under different technical parameters are quantified. This solves the problem that the technical parameters of the rotary tiller blade depend on manual definition, realizes the transformation from empirical parameter definition to quantitative technical optimization, reduces the number of physical prototype trials, shortens the design cycle of the rotary tiller blade, and the reduction of the contact area can effectively reduce the resistance effect caused by soil adhesion. This not only reduces the energy consumption of the rotary tiller blade during operation, but also improves the tillage efficiency and tillage quality of the rotary tiller blade.

[0133] In one example, the minimum threshold for the number of bond failures is 200,000, and the simulation optimization process is implemented using DesignExpert 13 software. Table 3 shows the simulation test results of the rotary tillage torque and the number of bond failures in a soil-tool coupling simulation system based on a rotary tillage blade operation model provided by an embodiment of the present invention.

[0134] Table 3

[0135]

[0136] In the example shown in Table 3, the rotary tillage condition represents minimizing the rotary tillage torque while ensuring sufficient soil breaking effect. Regression analysis of the simulation test results shown in Table 3 using response surface methodology yielded the optimal parameter combination: cutter shaft speed of 180 rpm, convex hull width of 10.6 mm, and convex hull spacing of 17.9 mm. Under this optimal parameter combination, the rotary tillage torque and the number of bond breakages in the soil-cutter coupling simulation system were 24.48 Nm and 210061, respectively.

[0137] Experimental testing revealed that in the soil-blade coupling simulation system built using a smooth-surfaced rotary tiller blade, the rotary tillage torque and the number of bond breakages were 30.15 Nm and 233,269, respectively. Therefore, although the soil-breaking effect of the rotary tiller blade operation model provided in this embodiment was reduced by 9.95%, it still meets the required range for soil-breaking performance. Furthermore, the rotary tillage torque was reduced by 5.67 Nm, resulting in an 18.81% improvement in anti-adhesion and drag reduction effects, achieving the optimal balance between anti-adhesion and drag reduction and efficient soil breaking.

[0138] Figure 15 This is a schematic diagram of the structure of a rotary tiller provided in one embodiment of the present invention, as shown below. Figure 15 As shown, the rotary tiller 300 includes a handle 310 and a blade 320 connected to the handle 310. The blade 320 is a trapezoidal straight blade, including a front tangent 321 along the rotary cutting direction, a side tangent 322 perpendicular to the rotary cutting direction, and a blade head 323 disposed away from the handle 310. The blade 320 is curved toward the side tangent 322.

[0139] In this embodiment, the surface of the blade 320 is arranged with a plurality of biomimetic convex structures 330, which are biomimeticly derived from pangolin scales. The rotary tiller 300 is obtained by using the rotary tiller design method as described in any embodiment of the present invention.

[0140] In an alternative embodiment, the biomimetic convex hull structure 330 is disposed on one of the side sections 322 or on two opposite side sections 322.

[0141] Among them, the front section 321 has the functions of cutting soil, turning soil, breaking soil, and throwing soil, while the side section 322 has the functions of cutting soil clods and breaking straw.

[0142] This invention also provides a rotary tiller, including a rotary tiller blade assembly, on which at least one rotary tiller blade as described in any embodiment of this invention is disposed. Exemplarily, the rotary tiller blade assembly further includes a blade shaft and a blade holder, with at least one rotary tiller blade mounted on the blade shaft via mounting holes to form a cutting tool, and the cutting tool mounted on the blade holder via screws or other connecting components.

[0143] The rotary tiller blade assembly in this embodiment can be directly adapted to existing rotary tillers without modifying the main body of the rotary tiller, thereby reducing the equipment modification cost for technology promotion.

[0144] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A biomimetic bump structure, characterized by, The bionic convex hull structure is obtained by imitating pangolin scales. The positive profile of the bionic convex hull structure is defined by a first parabola and a second parabola intersecting at two points, the cross-sectional profile is defined by a first circular arc based on a first radius, and the longitudinal cross-sectional profile is defined by a straight line intersecting at one point and a second circular arc based on a second radius, the first radius being greater than the second radius.

2. The biomimetic bump structure of claim 1, wherein The profile of the bionic convex hull structure is obtained by fitting according to profile coordinate data of the pangolin scales, the profile coordinate data being obtained by coordinate extraction on a profile image of the pangolin scales in a preset three-dimensional coordinate system.

3. The biomimetic boss structure of claim 2, wherein, The reference point of the preset three-dimensional coordinate system is the intersection of the longest transverse axis and the longest longitudinal axis of the pangolin scale, the transverse coordinate axis is along the width direction of the pangolin scale, the longitudinal coordinate axis is along the length direction of the pangolin scale, and the vertical coordinate axis is along the thickness direction of the pangolin scale. Correspondingly, the positive profile of the bionic convex hull structure satisfies the following fitting equation: ； The cross-sectional profile of the bionic convex hull structure satisfies the following fitting equation: ； The longitudinal cross-sectional profile of the bionic convex hull structure satisfies the following fitting equation: ； wherein represents the perpendicular distance of the vertex of the first parabola, represents the perpendicular distance of the vertex of the second parabola, represents the length of the pangolin scale, , represents half the width of the pangolin scale, represents the first radius, represents the height of the pangolin scale, represents the second radius.

4. A method of designing a rotary blade, characterized by: It comprises: Collecting a profile image of the pangolin scales, performing coordinate extraction on the profile image to obtain profile coordinate data, and performing curve fitting on the profile coordinate data to obtain a convex hull structure model, the convex hull structure model corresponding to the bionic convex hull structure of any one of claims 1-3; According to the base structure data of the rotary tiller, a base structure model is constructed; On the base structure model, a plurality of convex hull structure models are arranged according to the convex hull arrangement array to obtain a rotary tiller operation model, so as to complete the design of the rotary tiller. The bionic convex hull structure cooperatively imitates the frontal structure of the first parabola and the straight line towards the rotary cutting direction of the rotary tiller.

5. The method of designing a rotary blade according to claim 4, wherein The method further comprises: According to the convex hull structure model, a measuring disc corresponding to at least two preset arrangement arrays is prepared, and wet clay soil is selected as a soil sample; For each measuring disc, the measuring disc is pressed horizontally into the soil sample, and after standing for a preset time, the measuring disc is uniformly vertically lifted to obtain the pulling force value in the lifting process. After replacing the soil sample, the pressing and lifting operations are repeated, and a plurality of pulling force values are counted to obtain a pulling force standard value; The preset arrangement array corresponding to the smallest pulling force standard value is taken as the convex hull arrangement array of the bionic convex hull structure.

6. The method of designing a rotary blade according to claim 4, wherein After arranging a plurality of convex hull structure models on the base structure model according to the convex hull arrangement array to obtain a rotary tiller operation model, the method further comprises: The rotary tiller operation model is divided into a grid to obtain a discrete element model, the discrete element model is applied to a soil particle model to perform cutting simulation, and a rotary tillage performance index is obtained; According to the rotary tillage performance index, the rotary tiller operation model is simulated and optimized until the rotary tillage performance index meets the rotary tillage working condition to obtain a final rotary tiller operation model; In the simulation and optimization process, the optimization variable information is related to the contact area of the bionic convex hull structure and the soil.

7. The method of designing a rotary blade according to claim 6, wherein The optimization variable information includes at least one of a convex hull width, a convex hull spacing and a rotation speed of a blade shaft of the bionic convex hull structure.

8. The method of designing a rotary blade according to claim 7, wherein When the optimization variable information includes three optimization variables, the optimization scheme adopted by the simulation optimization process is a three-factor three-level regression scheme.

9. The method of designing a rotary blade according to claim 6, wherein When the cutting simulation corresponds to a sowing agricultural working condition, the rotary tillage performance index includes a rotary tillage resistance index and a particle crushing characteristic.

10. A rotary blade, characterized by, Comprising: a blade handle and a blade body connected to the blade handle, the blade body being a trapezoidal straight blade including a tangent plane in a rotary cutting direction, a side tangent plane perpendicular to the rotary cutting direction and a blade head arranged away from the blade handle, the blade body being curved towards the side tangent plane; a surface of the blade body is arranged with a plurality of bionic convex hull structures, the bionic convex hull structures being obtained by bionics of hedgehog scales, and the rotary tillage blade is obtained by using the design method of the rotary tillage blade according to any one of claims 4-9.

11. A rotary cultivator, characterized in that Comprising: a rotary tillage blade group, at least one rotary tillage blade according to claim 10 being arranged on the rotary tillage blade group. Comprising: a rotary tillage blade group, at least one rotary tillage blade according to claim 10 being arranged on the rotary tillage blade group.

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