General modeling method of wheat tiller geometry model based on discrete element method

Abstract

The present application belongs to the technical field of wheat plant modeling, and discloses a general modeling method of wheat plant tillering geometric model based on the discrete element method, which comprises: statistically analyzing shape parameters of wheat tillering plants to obtain single tiller modeling parameters and root system modeling parameters; constructing a single tiller model framework, including: a stem model and a wheat ear model; calculating expressions of each component spherical coordinate of the stem model and the wheat ear model according to the single tiller modeling parameters to obtain a single tiller general model; combining a single tiller general model as a main stem model and multiple single tiller general models as tiller plant models to obtain a plant general model; constructing a root system model framework, including: a tillering node model, a primary root model and multiple secondary root models; calculating expressions of each component spherical coordinate of the tillering node model, the primary root model and the secondary root models according to the root system modeling parameters to obtain a root system general model; and combining the root system general model with the plant general model to obtain a wheat plant tillering geometric general model.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of wheat plant modeling, and particularly relates to a general modeling method of a wheat plant tillering geometric model based on a discrete element method. BACKGROUND

[0002] As a major food crop in the world, wheat is widely planted in most areas of China by mechanization. In the process of wheat harvesting, conveying, threshing and cleaning, there is always interaction between wheat plants and agricultural machine components. The traditional design method of agricultural machine components is high in cost, long in cycle and strong in seasonality, which greatly limits the development of wheat harvesting machinery. Using the discrete element method to simulate the process of wheat harvesting machinery operation can intuitively obtain the movement trajectory and stress state of crops in the operation system, and can analyze the wheat harvesting operation mechanism from a micro perspective. It is necessary to accurately establish a wheat plant particle model to study the interaction between wheat plants and mechanical components and optimize the structure and working parameters of mechanical components.

[0003] Wheat plants are tillering crops, and the number and shape of wheat plant tillers are crucial to the cutting process. Existing wheat plant modeling methods only establish single tiller models, and their accuracy cannot meet the requirements of combined harvesting simulation. SUMMARY

[0004] The purpose of the present application is to provide a general modeling method of a wheat plant tillering geometric model based on a discrete element method, which can obtain an accurate general model of wheat plant tillering geometry and improve the modeling efficiency of the wheat plant tillering model.

[0005] The technical solution provided by the present application is as follows:

[0006] A general modeling method of a wheat plant tillering geometric model based on a discrete element method, comprising the following steps:

[0007] Step 1: Select multiple wheat tillering plants of multiple varieties, and measure the shape parameters of each wheat tillering plant;

[0008] Step 2: Statistically analyze the shape parameters of the wheat tillering plants to obtain single tiller modeling parameters and root system modeling parameters;

[0009] Step 3: Construct a single tiller model framework, which includes a stem model and a spike model; both the stem model and the spike model are composed of arranged balls; and

[0010] According to the expression of the coordinates of each component ball of the stem model and the spike model calculated based on the single tiller modeling parameters, a single tiller general model is obtained;

[0011] Step four, taking one of the single tiller universal model as the main stem model and multiple single tiller universal models as tiller models; combining the main stem model and the tiller models to obtain a plant universal model;

[0012] Step five, constructing a root system model framework, which includes a tiller node model, a primary root model and multiple secondary root models; each of the tiller node model, the primary root model and the secondary root model is composed of constituent spheres arranged in a tangential manner;

[0013] According to the expression of the coordinates of each constituent sphere of the tiller node model, the primary root model and the secondary root model calculated based on the root system modeling parameters, a root system universal model is obtained;

[0014] Step six, combining the root system universal model and the plant universal model to obtain a wheat plant tillering geometric universal model.

[0015] Preferably, the shape parameters of the wheat tillering plant include: the number of tillers, the growth angle of the tiller, the height of the wheat plant, the height ratio of each internode of the wheat stem, the length ratio of the ear axis, the growth angle of the spikelet, the angle between the side grain and the middle grain, the number of spikelets, the three-axis size of the grain, the number of primary roots, the number of secondary roots, the radius of the primary root, the radius of the secondary root, the length of the primary root and the length of the secondary root.

[0016] Preferably, the stem model is composed of multiple internode models, each of which is composed of constituent spheres arranged in a tangential manner, and the adjacent constituent spheres on two adjacent internodes are tangent to each other.

[0017] Preferably, the ear model includes an ear axis model and multiple spikelet models;

[0018] The ear axis model is composed of multiple constituent spheres arranged in a tangential manner along the axial direction of the ear axis;

[0019] The spikelet model includes a spikelet stalk model, a connecting sphere and a grain model;

[0020] The spikelet stalk model is a single sphere model, the grain model adopts a single ellipsoid model, and the grain model is connected to the spikelet stalk model through the connecting sphere.

[0021] Preferably, the tiller node model includes a main stem base model and multiple tiller base models;

[0022] The number and growth angle of the tiller base model correspond one-to-one to the number and growth angle of the tiller model; and the main stem base model and the tiller base model are each composed of multiple constituent spheres arranged in a tangential manner.

[0023] Preferably, the construction method of the tiller node model is as follows:

[0024] A root system spatial coordinate system is constructed with the center of the sphere formed by the end of the main stem base of the tillering node as the origin of the coordinate system and the main stem base model axis as the positive Z-axis.

[0025] The number of constituent spheres and the coordinates of each constituent sphere in the main stem base model are determined. The coordinates of each constituent sphere in the main stem base model are rotated around the Z-axis of the tillering space coordinate system to obtain the coordinates of each constituent sphere in multiple tillering bases.

[0026] Preferably, the multiple secondary root models are evenly distributed around the Z-axis of the root system spatial coordinate system at the bottom of the tillering node model; the secondary root model is composed of multiple constituent spheres arranged tangentially; the first j The second root model i The coordinates of the centers of the constituent spheres are:

[0027] ;

[0028] in,

[0029] ; ;

[0030] In the formula, This represents the translation transformation matrix of the secondary root along the Z-axis of the root system spatial coordinate system. This represents the radius of the sphere in the secondary root model composite. The transformation matrix representing the rotation of the secondary root about the Z-axis of the root system spatial coordinate system is given. The coefficients of the quadratic polynomial in the function representing the secondary root growth curve are represented. The coefficients of the first-order polynomial in the function representing the secondary root growth curve are... The constant term of the function representing the secondary root growth curve is... This indicates the number of secondary roots.

[0031] Preferably, the primary root models are evenly distributed around the Z-axis of the root system spatial coordinate system at the bottom of the tillering node model; the primary root model is composed of multiple constituent spheres arranged tangentially; the first j The second root model i The coordinates of the centers of the constituent spheres are:

[0032] ;

[0033] in,

[0034] ;

[0035] ;

[0036] In the formula, This represents the translation transformation matrix of the primary root along the Z-axis of the root system spatial coordinate system. representing the radius of the component sphere of the primary root model, representing the rotation transformation matrix of the primary root around the root system coordinate system Z representing the rotation transformation matrix of the axis, representing the number of the primary roots.

[0037] The present application has the following beneficial effects:

[0038] (1) The modeling method provided by the present application is obtained on the basis of analyzing a plurality of wheat plant structure parameters, and has strong universality.

[0039] (2) The tiller model for the wheat plant established by the present application is closer to the real situation of the wheat plant in morphological structure characteristics than the existing plant modeling method.

[0040] (3) The modeling method provided by the present application can obtain the coordinates of each component sphere by inputting the measured plant morphological parameters, without manually calculating the component sphere coordinate positions, can realize the parameterized modeling of the plant discrete element model, and greatly saves the modeling time.

[0041] (4) The present application extracts a plurality of key common feature shape parameters of different varieties of wheat plants on the basis of a large number of tests, which provides important data support for the feasibility of the wheat plant modeling. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 The flowchart of the universal modeling method of the wheat plant tiller geometric model based on the discrete element method described in the present application.

[0043] Figure 2 The component sphere particle arrangement diagram of the wheat plant single tiller model described in the present application; Figure 2 Fig. (a) is a schematic diagram of the arrangement method of the component sphere of the ear described in the present application; Figure 2 Fig. (b) is a schematic diagram of the arrangement method of the component sphere of the spikelet described in the present application; Figure 2 Fig. (c) is a schematic diagram of the arrangement method of the component sphere of the single tiller model described in the present application.

[0044] Figure 3 Fig. is a schematic diagram of the rotation transformation of the middle kernel and the connecting sphere in the spikelet described in the present application.

[0045] Figure 4 Fig. is a schematic diagram of the rotation transformation of the side kernel and the connecting sphere described in the present application.

[0046] Figure 5 Fig. is a schematic diagram of the arrangement of the component sphere of the root system model described in the present application.

[0047] Figure 6 Fig. is a schematic diagram of the arrangement of the component sphere of the tiller node described in the present application; Figure 6Fig. 1 is a front view of the ball arrangement mode of the tillering node according to the present application; Figure 6 Fig. 2 is a top view of the ball arrangement mode of the tillering node according to the present application.

[0048] Figure 7 Fig. 3 is a tillering model diagram of a wheat plant of Zhenmai No. 9 constructed in an embodiment of the present application.

[0049] Figure 8 Fig. 4 is a tillering model diagram of a wheat plant of Fannai No. 8 constructed in an embodiment of the present application.

[0050] Figure 9 Fig. 5 is a tillering model diagram of a wheat plant of Yangmai No. 12 constructed in an embodiment of the present application. DETAILED DESCRIPTION

[0051] The present application will be further described in detail below with reference to the accompanying drawings, so that those skilled in the art can implement the present application according to the description.

[0052] As shown in the accompanying drawings, Figure 1 the present application provides a general modeling method of a wheat plant tillering geometric model based on a discrete element method, and the specific implementation is as follows.

[0053] I. Select multiple plants of a variety to be modeled, and count the overall morphological parameters of the wheat plants in a field state.

[0054] The whole wheat plant is composed of one main stem and a plurality of tiller plants, and the growth angle of the tiller plant is , and the angle between adjacent tiller plants of the wheat plant is The angle is calculated by the following formula:

[0055]

[0056] wherein, represents the number of tiller plants.

[0057] II. Measure the shape parameters of the main stem and the tiller plants in the wheat plant respectively, and seek the correlation between the parameters.

[0058] The measured shape parameters of the main stem and the tiller plants include: the height of the wheat plant L , the height ratio of each internode of the wheat stem, the length ratio of the ear axis, the growth angle of the spike , the angle between the side grains and the middle grains (grain included angle ), the number of spikes , and the three-axis size of the grain (long semi-axis , middle semi-axis , and short semi-axis ). Then, the shape parameters of the main stem and the tiller plants are statistically analyzed, and the correlation between the parameters is sought, which specifically includes: calculating the mean value of the plant heightL , the proportion of plant height , determine the relationship between the outer diameter and the number of internodes, the relationship between the number of grains and the length of the ear and the average length of the grains , the average width and the average thickness .

[0059] the average plant height L The calculation method is to measure the length of each internode of the stem and the length of the ear axis respectively, and the average value is:

[0060]

[0061] In the formula, is the length of the nth internode of the mth plant sample, i is the number of measured internode samples. j , the length of the ear axis of the nth internode sample n . i The proportion of plant height can be expressed as:

[0062]

[0063]

[0064] In the formula, is the proportion of plant height of the nth internode. j The relationship between the outer diameter and the number of internodes can be expressed as:

[0065]

[0066]

[0067] In the formula, is the outer diameter of the internode, is the number of internodes. (The number of internodes is the order number of the internode, arranged in order from top to bottom)

[0068] The relationship between the number of grains and the length of the ear can be expressed as:

[0069]

[0070] In the formula, is the number of grains, is the length of the ear axis, is the first term coefficient of the relationship, is the constant term of the relationship.

[0071] the angle of spikelet growth is the angle between the central axis of the middle grain and the ear axis; the angle between the grains ​​​​This represents the angle between the lateral kernels and the central kernels. (This is the angle value for each variety.) , The values ​​are not consistent; different angle values ​​are selected for different varieties during modeling.

[0072] Third, by simplifying and analyzing the plant shape parameters, the plant model parameters required for modeling are obtained.

[0073] This invention uses a wheat plant model constructed by assembling constituent spheres. The wheat plant model includes an ear model and a stem model. The ear model consists of a spikelet model and a rachis model, and each spikelet model is further composed of a spikelet peduncle model, a connecting sphere, and a grain model; the stem model consists of multiple internode models.

[0074] The ear axis model is composed of multiple constituent spheres arranged tangentially along the axial direction; the grain model is tilted upwards at a certain angle to the ear axis model and connected to the spikelet peduncle model via connecting spheres. In this embodiment, a single ellipsoidal 9-sphere model is used as the wheat grain model.

[0075] To simulate processes such as ear cob breakage and grain shedding, the ear cob model, connecting ball, and grain model are combined and connected into a whole using a tangential arrangement.

[0076] To reduce model complexity, the number of grains per spikelet was uniformly set to 3 during modeling. The ear length was calculated based on plant height and the proportion of plant height, and the grain count was then determined using the formula relating grain count to ear length. The calculated grain count was then analyzed. Approximation is performed such that: So, the approximate number of grains for: , This represents the number of spikelets.

[0077] The ear axis model is composed of several ear node models arranged linearly with their ends tangent. Each ear node model is composed of the same number of constituent spheres, therefore the radius of the constituent spheres of the ear axis is... It can be represented as:

[0078]

[0079] In the formula, The number of ears formed by the nodes is [2-6], and the larger the value, the smaller the radius of the ear axis. This represents the average length of the spikelet nodes.

[0080] To ensure proper arrangement of wheat grains, prevent overlap, and avoid virtual bonds between non-adjacent grains, the radius of the constituent spheres of the spikelet peduncle model is set to twice the radius of the constituent spheres of the rachis model. The spikelet peduncle model and the wheat grain model are indirectly connected by connecting spheres. The spikelet peduncle model is a single-sphere model.

[0081] The number of constituent grains in the ear cob model It can be represented as:

[0082]

[0083] In the formula, The length of the rachis. The radius of the constituent sphere of the ear axis model.

[0084] The stem is slender and long with varying outer diameters at each node. Therefore, when modeling the stem, several identical constituent spheres are first arranged tangentially along the axial direction to form a length of... The j The intersegmental model, the first j The diameter of the constituent spheres of the intersegmental model With the j The outer diameters of the intersegmental models are consistent, and they are interconnected by adhesive keys. j The number of constituent balls in each intersegment model is:

[0085]

[0086] In the formula, For the first j The diameter of the constituent spheres in each intersegmental model; For the first j The length of each intersegment model.

[0087] Statistics show that most wheat stems consist of 5 internodes, with a few cases having 4 or 6 internodes. Therefore, in this embodiment, the main stem and the stems of each tiller of the wheat plant are defined as consisting of 5 internodes. The outer diameter of each internode is not consistent, so different component sphere radii are selected to represent the differences in the outer diameter of each internode. At the same time, to simulate the stem fracture process, the component spheres of each internode model and the adjacent component spheres between adjacent internode models are arranged tangentially.

[0088] Fourth, the coordinates of the constituent spheres are solved based on the geometric parameters of the main stem and tillers to obtain the coordinates of each sphere combination.

[0089] like Figure 2 As shown, during modeling, a three-dimensional global coordinate system is established with the center of the combined spheres at the bottom of the wheat ear axis as the origin. First, models of the wheat plant's ear axis and stem internodes are established along the positive and negative directions, respectively, along the Z-axis center.

[0090] The coordinates of the sphere formed by the ear axis can be represented as:

[0091]

[0092] In the formula: , , respectively represent the three-dimensional coordinates of the center of the i th component sphere (arranged in order from bottom to top) of the r th internode model of the spike axis,

[0093] Similarly, the coordinates of each component sphere of the stem internode can be expressed as:

[0094]

[0095] wherein, , , respectively represent the three-dimensional coordinates of the center of the j th component sphere (arranged in order from bottom to top) of the r i th internode model of the stem, , ; represents the number of component spheres of the r j th internode model; represents the radius of the r j th internode model; represents the radius of the spike axis.

[0096] The coordinates of the component spheres of the rachilla model can be expressed as:

[0097]

[0098] wherein, , , respectively represent the three-dimensional coordinates of the center of the r i th component sphere of the rachilla, , the number of spikelets.

[0099] The coordinates of the kernel and the connecting sphere on the spikelet model are relatively complex. First, a local coordinate system is established with the center of the combined sphere corresponding to the tangent point of the spike axis and the rachilla as the coordinate origin. Then, the kernel and the connecting sphere are subjected to translation and rotation transformation to obtain the coordinates of the kernel on each spikelet, as shown in Figures 3-4 .

[0100] As shown in Figure 3 , the initial values of the local coordinates of the connecting sphere in the spikelet model before transformation are:

[0101]

[0102] , , respectively represent the three-dimensional coordinates of the center of the connecting sphere.

[0103] The initial values of the local coordinates of the kernel in the spikelet are

[0104]

[0105] , , respectively represent the three-dimensional coordinates of the spherical center of the kernel model in the spikelet model, is the length of the semi-major axis of the kernel model.

[0106] Since the angle of spikelet growth is , and the spikelets are staggered on both sides of the spike axis, the angles between the upper and lower adjacent spikelets and the Z direction are respectively .

[0107] First, the initial connecting sphere and the kernel around the positive and negative directions of the X axis are rotated and transformed to obtain the intermediate kernel and the connecting sphere coordinates. Then, the transformation matrix of the intermediate kernel of the first spikelet i can be expressed as:

[0108]

[0109] As shown in Figure 3 , the local coordinates of the intermediate kernel and the connecting sphere spherical center after coordinate transformation are respectively:

[0110]

[0111]

[0112] As shown in Figure 4 , the angles between the side kernel and the connecting sphere and the intermediate kernel OXZ and the connecting sphere in the plane are , so the transformation matrix of the side kernel of the first spikelet i can be expressed as:

[0113]

[0114] Then the local coordinates of the side kernel and the connecting sphere after coordinate transformation are respectively:

[0115]

[0116] ​​

[0117] wherein, is the translation matrix, which can be expressed as:

[0118]

[0119] is the rotation matrix around the X axis, which can be expressed as:

[0120]

[0121] is the rotation matrix around the Y axis, which can be expressed as:

[0122]

[0123] Finally, the local coordinates of the spikelet model (connecting ball and grain) are converted to global coordinates:

[0124]

[0125]

[0126] wherein, , , are the global coordinates corresponding to the local coordinate origin of the i th spikelet, and the values are:

[0127]

[0128] In summary, the global coordinates of the centers of the middle grain and connecting ball of each component ball of the spikelet are:

[0129]

[0130]

[0131] The global coordinates of the centers of the side grain and connecting ball of each component ball of the spikelet are:

[0132]

[0133]

[0134] The coordinates of the component balls of the spike axis can be expressed as:

[0135]

[0136] 5. Combine the obtained wheat main stem and tiller models into a spherical local coordinate system to obtain the global coordinate system of the wheat plant tiller model.

[0137] The spherical coordinates of the main stem model can be represented as follows:

[0138]

[0139] In the formula, , , The coordinates of the center of the constituent spheres of the main stem model. , , The initial coordinates are those of the previously obtained single-cell model.

[0140] In the whole wheat tillering model, the first i The coordinates of the tiller model can be represented as:

[0141]

[0142] In the formula, , , For the first i The three-axis coordinates of a single-cell model. , , The initial coordinates are those of the previously obtained single-cell model.

[0143] in, It is the local coordinates of the single-cell model along Z The translation transformation matrix of the axis can be expressed as:

[0144]

[0145] It is a single-cell model with local coordinates around X The axis rotation transformation matrix can be represented as:

[0146]

[0147] In the formula, The angle of growth of the tiller.

[0148] It is the local coordinates of the single-cell model along Y The axis translation transformation matrix can be expressed as:

[0149]

[0150] The transformation matrix of the single-earth model around the Z-axis can be expressed as:

[0151]

[0152] In the formula, For tillering angle, The number of tillers, i The first tillering plant model represents the overall tillering plant model. i One tiller, .

[0153] VI. Construct a wheat root system model and solve for the spherical coordinates of the model components.

[0154] like Figure 5 As shown, the root system model consists of tillering nodes, primary roots, and secondary roots. Tillering nodes in wheat plants connect the root system to the main stem and each tiller. Therefore, tillering node parameters control the number of tillers and their growth angle. Because tillering nodes are hard and not easily broken, the tillering node model is constructed as a rigid, integral model. Primary roots are connected to the ends of tillering nodes, and secondary roots are evenly distributed in a ring along the ends of tillering nodes, representing the random deformation state of primary and secondary roots in the soil. Therefore, the constituent spheres of primary and secondary roots are connected in a tangential arrangement along the axial direction.

[0155] A root spatial coordinate system is constructed with the center of the sphere formed by the end of the main stem base of the tillering node as the origin of the coordinate system and the main stem base model axis as the positive Z-axis.

[0156] Tillering modeling methods such as Figure 6 As shown, the tillering node model includes: the main stem base, multiple tiller bases (corresponding one-to-one with the tillering plants), and the main root node. This forms a ball. ~ It forms the base of the main stem on the root tillering nodes, forming a ball. This constitutes the first tillering node on the root system. i The tillering base, the first i Each tillering base and Y The angle of the axis is .

[0157] In the root system, primary roots and the ends of tillering nodes form tangentially arranged spheres, while secondary roots form spheres uniformly distributed in a ring shape along the ends of the main root nodes within the tillering nodes. The constituent spheres of the primary root model are linearly tangentially arranged, and the growth curve of the secondary root model can be described by a quadratic function; therefore, the coordinates of its constituent spheres are tangentially arranged along the growth curve.

[0158] Composition of spheres The coordinates of the center of the sphere are The radius is 3 (set based on the average of measurements); forming a sphere The coordinates of the center of the sphere are ; Forming a ball The coordinates of the center of the sphere are ; The coordinates are .

[0159] Define the positive X-axis direction as the first tiller, and the tiller rotates around... Z The axes are evenly distributed, therefore the first... i Each tillering base forms a sphere. The coordinates of the sphere's center can be expressed as:

[0160]

[0161]

[0162]

[0163] The rotation matrix is:

[0164]

[0165] The main root node model (refers to the four constituent spheres at the bottom of the main stem base) In ), the first i Each component sphere The coordinates are The radius is 3.5 (obtained through measurement and statistics).

[0166] The number of secondary roots is defined as The growth curve of secondary roots is described by a quadratic function, where the first secondary root located in the positive X-axis direction of the root system spatial coordinate system is the second growth curve. i The constituent spherical coordinates can be represented as:

[0167]

[0168] No. j The first secondary root i Each component spherical coordinate can be represented as:

[0169]

[0170] in:

[0171]

[0172]

[0173] The local coordinates of the constituent spheres of the primary root can be represented as:

[0174]

[0175] Assume the number of primary roots is If they are evenly distributed around the Z-axis at the bottom of the tillering nodes, then the first... j The coordinates of the constituent spheres of a primary root can be represented as:

[0176]

[0177]

[0178]

[0179] Seven, the local coordinates of the root system (tiller node, primary root and secondary root) model are converted into the global coordinates of the plant model, to obtain the wheat plant tiller geometry general model.

[0180] The translation matrix is:

[0181]

[0182]

[0183] Eight, the parameters of the wheat plant to be modeled are input into the wheat plant tiller geometry general model, to obtain the wheat plant tiller model, and the coordinates of the centers of the constituent spheres can be derived. Embodiment

[0184] Using the wheat plant tiller modeling method provided by the application, the plant tiller model of Zhenmai No. 9 is constructed in the discrete element software AgriDEM2.0.

[0185] One, 30 Zhenmai No. 9 plants are randomly selected, and the shape parameters of each plant are measured, including stem parameters, ear parameters, root system and tiller parameters, as shown in Table 1.

[0186] Table 1 Wheat plant shape parameter table of Zhenmai No. 9

[0187]

[0188] Two, the plant parameters obtained in the above step are input into the wheat plant parameterized modeling module in the discrete element software AgriDEM2.0, and the coordinates of the wheat plant tiller model can be obtained, as shown in Table 2, and the obtained wheat plant tiller model of Zhenmai No. 9 is as shown in Figure 7 .

[0189] Table 2 Center coordinates of constituent spheres of wheat tiller model of Zhenmai No. 9

[0190]

[0191]

[0192]

[0193] Using the same method, Zhenmai No. 8 and Yangmai No. 12 plants are respectively modeled, and the obtained models are as shown in Figure 8and Figure 9 are shown.

[0194] While embodiments of the application have been disclosed in connection with the above specification and drawings this description is not intended to limit the scope of the application and many modifications, enhancements, alternatives, and variations will become apparent to those skilled in the art from this disclosure. Accordingly, it is expressly intended that the description should not limit the application as claimed but rather the only limitation placed on the scope of the application be the scope of the claims as set out below and equivalents thereof.

Claims

1. A general modeling method for the geometric model of wheat plant tillering based on the discrete element method, characterized in that, Includes the following steps: Step 1: Select multiple wheat tillers from multiple varieties and measure the morphological parameters of each wheat tiller. Step 2: Perform statistical analysis on the shape parameters of the wheat tillers to obtain the single-tiller modeling parameters and root system modeling parameters; Step 3: Construct a single-stalk model framework, which includes: a stalk model and a wheat ear model; both the stalk model and the wheat ear model are composed of arranged constituent spheres; and Based on the single-stalk modeling parameters, the expressions for the spherical coordinates of each component of the stalk model and the ear of wheat model are calculated to obtain the general single-stalk model; Step 4: Use one of the single-stalk universal models as the main stem model, and multiple single-stalk universal models as tiller models; combine the main stem model and the tiller model to obtain a plant universal model; Step 5: Construct a root system model framework, which includes: a tillering node model, a primary root model, and multiple secondary root models; each of the tillering node model, primary root model, and secondary root model is composed of constituent spheres. Based on the root system modeling parameters, calculate the expressions for the spherical coordinates of each component of the tillering node model, primary root model, and secondary root model to obtain the general root system model; Among them, multiple secondary root models are evenly distributed around the Z-axis of the root system spatial coordinate system at the bottom of the tillering node model; each secondary root model is composed of multiple constituent spheres arranged tangentially; the coordinates of the center of the i-th constituent sphere of the j-th secondary root model are: in, In the formula, T c R represents the translation transformation matrix of the secondary root along the Z-axis of the root system spatial coordinate system. c R represents the radius of the sphere in the secondary root model combination. z (γ c ) represents the rotation transformation matrix of the secondary root about the Z-axis of the root system spatial coordinate system, a r b represents the coefficients of the quadratic polynomial in the function of the secondary root growth curve. r c represents the coefficients of the first-order polynomial of the secondary root growth curve function. r N represents the constant term of the secondary root growth curve function. c Indicates the number of secondary roots; Step 6: Combine the root system general model with the plant general model to obtain the wheat plant tillering geometric general model.

2. The general modeling method for the geometric model of wheat plant tillering based on the discrete element method according to claim 1, characterized in that, The morphological parameters of wheat tillers include: number of tillers, growth angle of tillers, height of wheat plant, height ratio of each internode of wheat stem, length ratio of rachis, growth angle of spikelets, angle between lateral and central grains, number of spikelets, triaxial dimensions of grains, number of primary roots, number of secondary roots, radius of primary roots, radius of secondary roots, length of primary roots, and length of secondary roots.

3. The general modeling method for the geometric model of wheat plant tillering based on the discrete element method according to claim 2, characterized in that, The stem model is composed of multiple internode models, each of which is composed of constituent spheres arranged tangentially, with adjacent constituent spheres on two adjacent internodes being tangential.

4. The general modeling method for the geometric model of wheat plant tillering based on the discrete element method according to claim 3, characterized in that, The wheat ear model includes a rachis model and multiple spikelet models; The ear axis model is composed of multiple constituent spheres arranged tangentially along the axial direction of the ear axis; The spikelet model includes: spikelet pedicel model, connecting glomerulus and grain model; The spikelet peduncle model is a single-sphere model, the grain model is a single-ellipsoidal model, and the grain model and the spikelet peduncle model are connected by a connecting sphere.

5. The general modeling method for the geometric model of wheat plant tillering based on the discrete element method according to claim 3 or 4, characterized in that, The tillering node model includes: a main stem base model and multiple tillering base models; The number and growth angle of the tillering base model correspond one-to-one with the number and growth angle of the tillering plant model; both the main stem base model and the tillering base model are composed of multiple combined balls arranged tangentially.

6. The general modeling method for the geometric model of wheat plant tillering based on the discrete element method according to claim 5, characterized in that, The method for constructing the tillering node model is as follows: A root system spatial coordinate system is constructed with the center of the sphere formed by the end of the main stem base of the tillering node as the origin of the coordinate system and the main stem base model axis as the positive Z-axis. The number of constituent spheres and the coordinates of each constituent sphere in the main stem base model are determined. The coordinates of each constituent sphere in the main stem base model are rotated around the Z-axis of the tillering space coordinate system to obtain the coordinates of each constituent sphere in multiple tillering bases.

7. The general modeling method for the geometric model of wheat plant tillering based on the discrete element method according to claim 6, characterized in that, Multiple primary root models are evenly distributed around the Z-axis of the root system spatial coordinate system at the bottom of the tillering node model; each primary root model is composed of multiple constituent spheres arranged tangentially; the coordinates of the center of the i-th constituent sphere of the j-th primary root model are: in, In the formula, T zg R represents the translation transformation matrix of the primary root along the Z-axis of the root system spatial coordinate system. zg R represents the radius of the constituent spheres of the primary root model. zg (γ P ) represents the rotation transformation matrix of the primary root about the Z-axis of the root system spatial coordinate system, N p This indicates the number of primary roots.

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