Grain posture correction element of belt type high-speed soybean seed guide device and design method of grain posture correction element

Abstract

The invention discloses a grain posture correction element of a belt type high-speed soybean seed guide device and a design method thereof, and relates to a high-speed precision seeding technology. In order to solve the problems that the posture of seeds in a single seed cavity is unstable and the positions are inconsistent when the belt type seed guide device is used for sowing at a high speed, the grain posture correction element of the belt type seed guide device is characterized in that the grain posture correction element is composed of five-order parallel cross grains; when the soybeans are in contact with the first-order cross grains, the soybeans can be adjusted to enable long axes of grains to be perpendicular to the running direction of the seed conveying belt for stable seed guiding. And determining the theoretical two-dimensional seed conveying position of the seeds in the correction area by analyzing the states of the seeds in the collision deformation stage and the collision recovery stage. EDEM discrete element simulation software is used for conducting a cross grain correction optimal height simulation test, the inclination angle qualification rate and the offset qualification rate serve as test evaluation indexes, the displacement curve of the seeds from the limiting-correction transition stage to the correction stage end point is analyzed through a single-factor test, and the migration rule of the cross grain correction height to the transverse direction of the seeds is defined. A contrast test shows that the posture variable coefficient and the plant spacing variable coefficient of the belt type seed guide device with the correction element are lower than those of the belt type seed guide device without the correction element, and the requirement of high-speed precision seeding operation can be met.

Description

Technical Field

[0001] The invention relates to a high-speed precision seeding technology, and in particular to a seed posture correction element of a belt-type soybean high-speed seed guiding device and a design method thereof. Background Art

[0002] In order to improve the efficiency and quality of soybean sowing operations, high-speed precision sowing technology has become the main direction of soybean sowing equipment development. [1] This technology mainly uses the seed meter and seed guide device to achieve accurate seeding, stable seeding and precise seed implantation. [5][6] , especially the belt-type high-speed seed guide device, which can guide the seeds from the seed tray into the seed cavity of the seed guide belt and then to the seed bed, while effectively preventing the seeds from bouncing and colliding in the inner cavity of the seed guide device or between the paddles, thereby accurately controlling the single-seed sowing rate. The uniformity of seed distribution after sowing is a key factor affecting crop emergence and yield. However, soybeans have inconsistent postures during the seed transportation process, resulting in the long axis of the seeds failing to follow the forward direction of the machine when they reach the seeding point, causing the soybeans that fall into the seed bed to bounce and roll, reducing the uniformity of sowing. [7] To further explore the order of seeds in the seed guide device

[12] Therefore, a belt-type high-speed seed guide device with a grain posture correction element was developed to achieve the adjustment of seed posture and effectively solve the problems of random bouncing of seeds in the seed cavity and uneven sowing.

[0003] Domestic and foreign scholars have conducted extensive research on belt seed guide devices. John Deere Company, USA

[13] A brush belt seed guide device was developed to eliminate seed collision during high-speed seed guide, but continuous high-speed operation will increase the coefficient of variation of seed spacing; Precision Planting, an American company, developed the Speed ​​Tube belt high-speed seed guide device.

[14] , by constraining the freedom of seeds, random collisions between seeds and seed guide elements are reduced, but there are no studies on the stability of seed delivery position and consistency of posture; Chen Xuegeng

[15] A belt-type seed guide device was designed to improve sowing uniformity by reducing the seed placement height, but the transition of the seeds from the seed tray to the seed guide belt was in an unconstrained state; Liu Quanwei

[16] A belt seeding device was designed to achieve precise seed displacement, but the operating speed should not exceed 9.7 km / h; Wang Xiying et al.

[17] Designed a double-row staggered belt seeding device, which can improve sowing uniformity by limiting seed movement and performing zero-speed sowing; Chen Yongliang

[18] Ma Chengcheng

[19] He Feng Zhaohua

[21] A fully constrained belt-type high-speed seed guide device is designed, which limits the freedom of seeds to fall into the seed cavity through the seed receiving mechanism, ensuring a high qualified rate and low reseeding rate during sowing. However, the existing seed receiving mechanism cannot ensure that the seeds are transported with their long axis visualized and perpendicular to the seed transport direction after being placed in the seed cavity. Therefore, it is necessary to design a correction element that can correct the long axis position of the seeds to achieve seed orientation adjustment for directional seeding. Summary of the invention

[0004] The technical problems to be solved by the present invention are:

[0005] In order to solve the problem that the seed receiving mechanism of the existing belt-type soybean high-speed seed guiding device cannot ensure that the seeds are transported with the long axis visualized and perpendicular to the seed transport direction after being put into the seed cavity, and cannot achieve the seed posture adjustment for directional seed sowing, the present invention further provides a seed posture correction element of the belt-type soybean high-speed seed guiding device and a design method thereof.

[0006] The technical solution adopted by the present invention to solve the above technical problems is:

[0007] A seed posture correction element for a belt-type soybean high-speed seed guide device, the seed posture correction element is used to be set in the correction area of ​​the belt-type soybean high-speed seed guide device to correct the seed posture, the seed posture correction element is a strip-shaped block, and the two sides of the correction element are respectively provided with front and back shell fixing columns, which are used to firmly fix the correction element to the shell fixing hole, and the correction element relies on transverse stripes for posture correction, and one side surface thereof is provided with five-order parallel transverse stripes, and every three-order transverse stripes correspond to a seed cavity (two seed cavities), so as to increase the correction range.

[0008] The selection of the horizontal stripe height h should take into account the distance between the shell and the paddle, and only needs to achieve the correction effect; the length of the correction element L = 3N, and the distance between the two outermost horizontal stripes L 0 =0.9L,L 0 =N / 2;;L 0 is the actual working length, and N is the number of seed cavities. A boss is provided on the corresponding surface of the side surface with five-order parallel horizontal lines, and the boss is used to cooperate with the socket at the corresponding position of the seed guide device housing.

[0009] A design method for a seed posture correction element of a belt-type soybean high-speed seed guiding device, the implementation process of the method is as follows:

[0010] Correction element parameter determination

[0011] The seeds are transported to the correction element by the thrust of the paddle, and the direction of the long axis of the seeds is adjusted by contact and collision, ensuring that each seed is visualized with its long axis and is transported perpendicular to the seeding direction, so that it can be accurately delivered in a uniform posture at the seeding port. The correction element is the core element for correcting the posture of the seeds. The material and the height of the horizontal grain directly affect the position of the seeds in the seed cavity of the seed transport belt. The correction element must ensure that the seeds do not deform significantly after contact with the correction element, and the displacement after collision should not be too large. It is made of nitrile rubber (NBR) material with high stability and impact resistance, excellent wear resistance and heat resistance. The material characteristic parameters are as follows: Mooney viscosity / MU is 82, hardness / Shore A is 74, and compression permanent deformation / % is 23;

[0012] The selection of the horizontal grain height h should take into account the distance between the shell and the paddle, L = 3N, L 0 =0.9L,L 0 =N / 2; L is the length of the correction element, mm; L 0 is the actual working length, mm, N is the number of cavities;

[0013] Mechanical analysis of the correction process

[0014] Based on the relationship between the correction performance of the correction element and the posture change of the seed in the seed cavity, a seed mechanical model during the correction process (corresponding to Formula 1) was established, and the force condition of the seed during the correction stage was analyzed. The collision process of the seed was divided into the collision deformation stage and the collision recovery stage. The soybean was regarded as a uniform, isotropic ellipsoid with a very small contact area. The contact force condition was non-common, and the deformation amount during the contact process was much smaller than the size of the soybean. The movement direction of the soybean was perpendicular to the placement of the seed conveyor belt.

[0015] The relationship between the transverse grain height h of the correction element and the coordinates of the soybean seeds in the correction area after correction is obtained through mechanical analysis of the correction process.

[0016] Keywords in the present invention include: soybean, high-speed precision seeder, belt-type seed guiding device, grain correction and directional seed guiding.

[0017] The present invention has the following beneficial technical effects:

[0018] A grain posture correction element for a belt-type high-speed seed guiding device is designed and studied in the present invention. The height of the transverse grain is corrected through theoretical design, and a simulation test is conducted on the influencing mechanism of the ordered state of seeds to determine the consistency between the corrected transverse grain height and the theoretical analysis. Subsequently, bench performance tests and comparative tests are carried out, and the correction effect is quantified using the coefficient of posture variation to verify the effectiveness of the correction effect, thereby realizing the function of correcting the seed posture.

[0019] The invention designs a seed posture correction element for a belt-type seed guide device, which solves the problem of unstable seed posture and inconsistent position in a single seed cavity when the belt-type seed guide device is sown at high speed (13-16 km / h). The element is composed of five-order parallel horizontal stripes and is made of nitrile rubber material. When the soybean contacts the first-order horizontal stripes, it will be adjusted so that the long axis of the seed is perpendicular to the running direction of the seed conveying belt for stable seed guidance. By analyzing the state of the seed in the collision deformation stage and the collision recovery stage, the theoretical two-dimensional seed conveying position of the seed in the correction area is clarified. The EDEM discrete element simulation software is used to perform a simulation test on the optimal height of the corrected horizontal stripes. The qualified rate of the inclination angle and the qualified rate of the offset are used as test evaluation indicators. The displacement curve of the seed from the limit-correction transition stage to the end point of the correction stage is analyzed through a single factor test to clarify the law of the horizontal movement of the seed by the height of the corrected horizontal stripes. A single factor comparative test is performed using high-speed camera technology, and a correction effect comparative test is performed using the coefficient of variation of the posture and the coefficient of variation of the plant spacing as indicators. Comparative tests show that the posture variation coefficient and plant spacing variation coefficient of the belt-type seed guide device with correction elements are lower than those of the belt-type seed guide device without correction elements; when the operating speed is increased from 13km / h to 16km / h, the decrease in the posture variation coefficient of the belt-type seed guide device with correction elements increases from 13.75% to 19.04%, and the decrease in the plant spacing variation coefficient increases from 10.14% to 15.31%, which can meet the requirements of high-speed precision seeding operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the structure of a belt-type high-speed seed guide device, in which: 1-main dial finger wheel, 2-secondary dial finger wheel, 3-anti-stuck limit block, 4-seed row motor, 5-belt speed monitoring module, 6-seed guide belt, 7-tensioning mechanism, 8-driven pulley, 9-seed delivery port, 10-seed cavity, 11-paddle, 12-seed belt housing, 13-correction element, 14-driving pulley, 15-reduction gear box, I-seed receiving area, II-correction area, III-seed delivery area, IV-seed delivery area;

[0021] Figure 2 This is a schematic diagram of the seed movement;

[0022] Figure 3 It is a schematic diagram of posture adjustment, in which: Ⅰ-limit adjustment area, Ⅱ-limit-correction transition area, Ⅲ-correction area;

[0023] Figure 4 The trajectory of seed casting, in the figure: (a) schematic diagram of seed casting without correction, (b) schematic diagram of seed casting with correction;

[0024] Figure 5 is a schematic diagram of the correction element structure;

[0025] Figure 6 This is a schematic diagram of collision deformation;

[0026] Figure 7 This is a simplified diagram of velocity analysis at the seeding port;

[0027] Figure 8 This is a simplified diagram of the collision analysis between the seed and the boss;

[0028] Fig. 9 It is a schematic diagram of different horizontal stripe heights of the correction element;

[0029] Fig.10 It is a soybean simulation model;

[0030] Fig.11 It is a simulation model of the seed guiding device;

[0031] Fig.12 Correction of migration trajectory map for seeds;

[0032] Fig.13 The results of the EDEM virtual simulation correction test are shown. The lateral displacement and longitudinal displacement of the seed when the height h of the horizontal stripes on the correction element is 0.50mm, 0.75mm, 1.00mm, 1.25mm, and 1.50mm respectively. It can be seen that when the height h of the horizontal stripes is 1.00mm, the seed can be located on the center line of adjacent paddles in an ideal posture, and the seed will always be pushed by the upper paddle in the seed cavity.

[0033] Fig.14 It is a test bench for correcting component performance testing, in the figure: 1, high-speed camera 2, seed bed belt 3, test bench operating platform 4, image acquisition software 5, belt-type soybean high-speed seed guiding device 6, air-suction soybean precision seed metering device 7, negative pressure fan 8, control box;

[0034] Fig.15 Corrective element for optimum convex height;

[0035] Fig.16 This is a diagram of the correction process under high-speed photography;

[0036] Fig.17 Graph showing sowing performance with and without corrective elements. DETAILED DESCRIPTION

[0037] 1 Working principle of belt seed guide device

[0038] The belt-type soybean high-speed seed guide device is mainly composed of a main finger wheel, an auxiliary finger wheel, an anti-stuck limit block, a seeding motor, and a belt speed monitoring module.

[22] , seed guide belt, tensioning mechanism, driven pulley, seeding port, seed cavity, paddle, seed belt housing, correction element, active pulley, reduction gear box, etc., divided into four blocks: seed collection, correction, seed delivery, and seeding. The overall structure of the belt-type high-speed seed guide device is as follows Figure 1 shown.

[0039] When the belt seed guide device is working, the seed guide motor drives the gear transmission in the tilted state of the seed guide belt to rotate, and the seeds are transported from the seed discharge hole of the seed meter to the seed cavity of the seed transport belt by rotating clamping.

[24] . Since the device runs at high speed, the position of the seeds just falling into the seed cavity is random. Therefore, after the seeds contact the anti-stuck limit block, the seeds will be adjusted to the correct seed delivery route. Since the linear speed of the seed guide belt paddle is greater than the falling speed of the seeds, the seeds will always be pushed by the upper paddle in the seed cavity until the seeds complete the planting process.

[0040] 2. Correction element design

[0041] 2.1 Working principle of correction element

[0042] The belt-type high-speed seed guide device has limited the large collision of seeds in the seed cavity. Because the seeds have different initial velocities when leaving the seed receiving mechanism, the thrust of the paddle on the seeds is inconsistent, and the seeds move in the seed cavity. Figure 2 As shown, the seed posture at the seeding point of the seed guide device is not uniform, resulting in a decrease in sowing uniformity.

[0043] During high-speed operation, the seed guide motor drives the main finger wheel of the seed guide belt in an inclined state through the gear transmission, so that the seed receiving mechanism rotates and clamps the single grain into the seed cavity.

[25] At this time, the seeds will be transported in three different postures. In order to ensure that the seeds always maintain a stable long-axis state and the same planting posture during the planting process, it is necessary to correct the posture of the seeds that have just entered the linear motion in time to ensure that the seeds maintain the same and stable posture under high-speed working conditions to complete the planting process. Therefore, the long axis of the seeds is first adjusted to the two states of the limit-correction transition stage through the limit blocks of the left and right staggered structures, so that the seeds can complete the migration with the long axis visualized. Then, the seeds are transported to the correction element by the thrust of the paddle, and the direction of the long axis of the seeds is adjusted by contact and collision. It is ensured that each seed is transported with the long axis visualized and perpendicular to the planting direction, so that they can be accurately placed in a uniform posture at the seeding port. Limiting elements such as Figure 3 shown.

[0044] The limit adjustment area can adjust the seeds to be transported in a long-axis visible posture, reducing the phenomenon of seeds bouncing and rolling after falling into the seed bed, such as Figure 4 The correction area can reduce the bouncing and collision of seeds transported along the inclined seed guide belt in the high-speed operation seed cavity, and reduce the wear of seeds and the seed guide belt shell.

[0045] 2.2 Determination of correction element parameters

[0046] The correction element is the core element for correcting the seed posture. The material and the height of the cross grain directly affect the position of the seed in the seed cavity of the seed conveyor. The correction element must ensure that the seed does not deform significantly after contact with the correction element, and the displacement after collision should not be too large. Therefore, it is made of nitrile rubber (NBR) material with high stability and impact resistance, excellent wear resistance and heat resistance.

[26] It is more in line with the correction of seed posture by the correction element of the belt-type soybean high-speed seed guide device. The material characteristic parameters are shown in Table 1.

[0047] Table 1 Correction element parameters

[0048]

[0049] The corrective element is provided with a front and back housing fixing column on both sides, which is used to securely install the corrective element on the housing fixing hole. The corrective element relies on the horizontal stripes for posture correction. Its surface is composed of five-order parallel horizontal stripes, and every 3-order horizontal stripes corresponds to a seed cavity, thereby increasing the correction range. The selection of the horizontal stripe height h should take into account the distance between the housing and the paddle, and it is only necessary to achieve the correction effect. L = 3N, L 0 =0.9L,L 0 =N / 2; L is the length of the correction element, mm; L 0 is the actual working length, mm, N is the number of cavities, such as Figure 5 shown.

[0050] 3 Mechanical analysis of the correction process

[0051] In order to study the correction performance of the correction element and the change of the posture of the kernel in the seed cavity, a kernel mechanical model during the correction process was established, and the force conditions of the kernel during the correction stage were analyzed.

[28] The collision process of seeds is divided into collision deformation stage and collision recovery stage. For the convenience of theoretical analysis, soybeans are regarded as uniform, isotropic ellipsoids. The contact area is very small, the contact force is non-common, the deformation in the contact process is much smaller than the size of soybeans, and the movement direction of soybeans is perpendicular to the placement of the seed conveyor belt.

[0052] 3.1 Seed movement analysis

[0053] The correction element mainly adjusts the long axis position of the seeds during the seeding stage by destroying the stable state of the soybeans, so the deformation process of the collision between the soybeans and the correction element is analyzed. 1 , the thrust F of the pick on the grain 0 , the support force of the correction element on the grain F N, the friction force on the grain and the grain's own gravity G, the angle α between the collision force and the y-axis, and the installation angle β of the seed guide. With the center of the grain as the coordinate origin o, the x-axis perpendicular to the grain's movement direction and the y-axis as the grain's movement direction, a rectangular coordinate system xoy is established, such as Figure 6 shown.

[0054] From the collision analysis between soybean and correction element, we know that if we want to ensure the stable seed delivery in the seed cavity, ω has only two results: 0° or 90°. According to D'Alembert's principle, the mechanical equation of soybean seed is:

[0055]

[0056] Where F f ——Contact friction between soybean and correction element, N;

[0057] m——soybean mass, g;

[0058] k is the friction coefficient of the contact surface.

[0059] Formula (1) represents the balance between the contact friction between the seed and the correction element and other forces during the collision. The coordinates of the soybean seed after the collision (x 0 ,y 0 )for

[0060]

[0061] Where x is the displacement of the pick, mm;

[0062] a——length of the major axis of soybean seeds, mm;

[0063] x 0 ——The horizontal coordinate of the plane where the seed is located;

[0064] y 0 ——The vertical coordinate of the plane where the seed is located.

[0065] To ensure that the seed corrects its posture with minimal energy consumption, the force F acting on the seed against the correction element is 1 The angle α between the Y axis and the seed should be the minimum. At the same time, the horizontal component of the speed of the paddle hitting the seed should be equal to the forward speed of the machine and opposite in direction, ensuring that its speed in the horizontal direction is zero. At this time, the thrust F 0 for

[0066]

[0067] Where V 0 ——Initial velocity of soybean, mm / s;

[0068] V 1——pick speed, mm / s;

[0069] dV 0 / dt——V 0 Derivative, mm / s 2 .

[0070] Combining formula (3) we can get

[0071]

[0072] By analyzing the speed conversion relationship between the machine operating speed and the linear speed of the seed guide belt, it can be known that the relationship between the angle μ between the linear speed of the paddle at the seeding port and its horizontal component speed and the inclination angle β of the seed guide belt is as follows: Figure 7 As shown, the relationship between the paddle linear speed and the tool operating speed is:

[0073]

[0074] Where V 2 ——Machine operating speed, km / h;

[0075] γ – the angle formed by the pulley line and the seeding point, γ = 166.5°.

[0076] Integrating equations (2), (4), and (5), the coordinates of soybean seeds at the time of transplanting are:

[0077]

[0078] Where b is the length of the short axis of soybean seeds, mm;

[0079] 3.2 Collision deformation process

[0080] If the seed in the offset center position is not corrected by the correction element, the seed will collide with the seed guide shell in the seed cavity, resulting in seed damage and random position. In order to keep the seed in the best posture to complete the seeding process and reduce the occurrence of wear, the collision deformation and recovery stages of the seed and the correction element are further analyzed. The collision deformation analysis diagram is shown below. Figure 8 shown.

[0081] Coefficient of restitution e during deformation of soybean-correction element collision n , e τ = 0. According to Hertz theory, the contact area size between the seed and the correction element is theoretically calculated. The larger the contact area size, the wider the collision force distribution, resulting in increased deformation, which affects the stability of the seed posture and the seeding effect. The contact area size between the seed and the correction element is

[0082]

[0083] Where c is the contact area size, mm;

[0084] R e ——equivalent relative radius of curvature, mm;

[0085] R 1 ’ ——Maximum radius of curvature of the corrective element in the contact area, mm;

[0086] R 1 ” ——Minimum radius of curvature of the corrective element in the contact area, mm;

[0087] R 2 ’ ——The maximum curvature radius of the seed in the contact area, mm;

[0088] R 2 ” ——Minimum curvature radius of the seed in the contact area, mm;

[0089] E 1 ——elastic modulus of the correction element, Pa;

[0090] E 2 ——Elastic modulus of soybean, Pa;

[0091] K——constant determined by the principal radius of curvature;

[0092] μ 1 - Poisson's ratio of the corrective element;

[0093] μ 2 ——Poisson’s ratio of the kernel;

[0094] δ 1 ——Collision compression of rice;

[0095] δ 2 ——Collision compression of threshing elements.

[0096] From formula (7), we can know that the contact area size c is related to the thrust F exerted by the paddle on the seed. 0 is positively correlated, that is, the speed of the seed guide belt V 1 The faster the pick is, the greater the thrust it gives to the seed, and the greater the angle between the line connecting the contact point and the center of gravity of the soybean and the y-axis. The angle affects the component velocity and impulse generated when the seed collides. Since the displacement of the seed is limited when changing its posture, the seed may bounce repeatedly, so the height of the corrected cross grain is changed to reduce the occurrence of the bouncing problem. According to the Lagrange equation of collision, the seed angular velocity ω and the collision impulse I are theoretically calculated to analyze the motion trajectory of the object under collision or constraint conditions. To analyze whether the energy of the system has been effectively utilized or converted, the relative total kinetic energy T* of the system is

[0097]

[0098] Where J is the moment of inertia of soybean, g·mm 2 .

[0099] The corresponding generalized impulse formula is

[0100]

[0101] Combining equations (8) and (9) to obtain another form of the collision Lagrange equation:

[0102]

[0103] Plastic collision has constraint conditions V An =V Aτ =0, we get

[0104]

[0105] It can be seen from formula (11) that the angular velocity of the seed is negatively correlated with the cross-grain height h of the correction element. Therefore, in the collision deformation process, the choice of cross-grain height directly affects the seed posture correction effect. Not only is there enough energy to adjust the seed posture, but also the deformation energy stored in the correction element needs to be partially converted back to kinetic energy. Therefore, the collision recovery stage needs to be considered, that is, when the force at the contact point gradually decreases and the object begins to restore its original shape.

[0106] 3.3 Collision recovery process

[0107] The recovery coefficient e of the seed and the correction element during the collision process is set to 0. In the collision recovery stage (e≠0), ω', V An '、V Aτ ' represents its generalized velocity, and its total kinetic energy is

[0108]

[0109] Similarly, integrating equation (12) into another form of the collision problem Lagrange equation yields

[0110]

[0111] Definition of collision restitution coefficient I' n =e n I n , I' τ =e τ I τ Solved

[0112]

[0113] When the collision between the seed and the correction element ends, the soybean seed will move with the paddle in a uniform and stable state. Substituting equation (14) into equation (6) we can get the coordinates of the soybean at this time (x 0 ,y 0 )for

[0114]

[0115] According to formula (15), the coordinates of the corrected soybean seeds in the correction area are negatively correlated with the corrected horizontal grain height. Therefore, experimental optimization should be carried out based on the influence of different horizontal grain heights on the degree of seed deviation.

[0116] 4 Simulation test

[0117] In order to explore the effect of the corrected transverse grain height h on the operation effect of the correction element of the belt-type seed guide device on the seed posture, the reasonable transverse grain height h of the correction element was determined, and the correction models with transverse grain heights h of 0.50 mm, 0.75 mm, 1.00 mm, 1.25 mm, and 1.50 mm were established respectively. Fig. 9 As shown in the figure, the coordinate change of soybean in the seed guide belt cavity is taken as the indicator, and the connection line of the long axis of the seed is taken as the judgment basis. The EDEM2022 simulation software is used to simulate the correction test process of the belt seed guide device.

[0118] 4.1 Simulation model establishment

[0119] This paper takes "Dongnong 52" seeds as the research object. The 100-grain weight is measured by a microcomputer automatic grain counter and an electronic balance, which is 0.207g. The three-axis dimensions are measured by a vernier caliper, which is 7.52×6.54×6.26mm, and the average density is 1.267g / mm 3 To facilitate the three-dimensional modeling of soybean seeds and distinguish the long axis of soybeans, soybeans can be regarded as ellipsoids with a long axis of 7 mm and the other two axes of 5.5 mm. Fig.10 shown.

[0120] Use Solidworks drawing software to create the belt-type seed guide device and correction components, and convert the model into .STL format and import it into EDEM software, such as Fig.11 As shown in the figure, the function of the seed guide belt receiving mechanism is to receive the seeds on the air suction seeding disc to the seed guide belt. Therefore, the particle factory that generates seeds is set in the limit-correction transition zone. The simulation test selects 5 correction elements with different protrusion heights, and the selected forward speeds are 13-16 km / h.

[0121] The seed transport route of the seed in the seed guide cavity can provide feedback on the degree of correction of the seed by the correction element, and the speed fluctuation of the correction element can provide feedback on the seed transport route of the seed flow. In order to clarify the correction effect of the correction element on the seed, the EDEM2022 simulation software was used to carry out a simulation test of the contact between the seed and the correction element. The global variable parameters are shown in Table 2.

[0122] Table 2 Global variable parameters

[0123]

[0124] 4.2 Evaluation Metrics

[0125] In order to provide a consistent posture evaluation method for the influence of the correction element on the sowing operation effect, the test selected the inclination angle qualified rate S and the offset qualified rate Q.

[0126] Qualified range of inclination angle: the inclination angle between the long axis of the seed and the contact strip Less than 45° is a qualified inclination angle. The calculation formula of attitude index W is:

[0127]

[0128] The calculation formula of the inclination pass rate S is:

[0129]

[0130] In the formula, n 1 is the number of qualified inclination angles;

[0131] N is the total number of trials.

[0132] Offset qualified rate Q: The vertical distance from the seed center to the line connecting the midpoints of adjacent picks is less than 0.2 times the length of the pick, which is considered qualified. The calculation formula is:

[0133]

[0134] In the formula, n 2 is the offset qualified quantity.

[0135] 4.3 Simulation results and analysis

[0136] In order to verify the effect of correcting the height of the horizontal grain on the posture of the grain, a plane rectangular coordinate system is established with the lower left corner of the correction element as the origin, the outer shell of the seed guide belt as the origin o, the direction of the shell on the other side as the positive semi-axis of the x-axis, and the reverse direction of the movement direction of the paddle as the positive semi-axis of the y-axis. Fig.12 shown.

[0137] In the correction simulation test, the heights of the corrected horizontal stripes were selected to be 0.50mm, 0.75mm, 1.00mm, 1.25mm, and 1.50mm, respectively. Three tests were conducted at operating speeds of 13km / h, 14km / h, 15km / h, and 16km / h, respectively. The average value of the seed coordinate movement trajectory points at the same moment was taken according to the established plane rectangular coordinate system, and the displacement diagram of the seed from the limit-correction transition stage to the end point of the correction stage was drawn, that is, the change law of the movement trajectory after correction. The test results are shown in Figure 2. Fig.13 shown.

[0138] Depend on Fig.12 It can be seen that different cross-grain heights on the correction element have different results on seed posture correction. When the cross-grain height is 0.50mm, due to the low cross-grain height, it cannot provide sufficient correction force. It is difficult for seeds to maintain a stable posture during the seeding process, and multiple corrections occur. When the cross-grain height is 0.75mm, there is still a certain posture fluctuation. Although it is better than the correction effect of 0.50mm, the long axis of the seed is offset during the seeding process, but it is still not enough to maintain the best seeding posture. When the cross-grain height is 1.00mm, the seeds can be in an ideal posture. The posture is located on the center line of adjacent paddles, and the fluctuation phenomenon is significantly reduced, which can achieve stable seed feeding effect at different speeds and effectively avoid the jumping of seeds in the cavity; when the height of the horizontal stripes is 1.25mm, although the seed posture can be effectively corrected, the seeds are subject to excessive interference during the correction process, and there is a more obvious phenomenon of deviation from the center of the paddles, which increases the instability of the posture; when the height of the horizontal stripes is 1.50mm, the seeds cannot be kept at the position of the center line of adjacent paddles, and the correction element produces greater instability and jumping phenomenon for the correction of seeds. The irregular waveform jumping appears in the figure, indicating that the seeds are in a state of breaking through, and the seeds lose stability in the seed cavity. Subsequently, due to energy loss, the seeds tend to be in a long-axis stable state. In order to verify the results of stable seed feeding in the simulation test, the height of the corrected horizontal stripes is selected as 1mm, and the operating speeds are 13-16km / h, respectively. A total of 3 groups of tests are carried out for each operating speed, and 500 consecutive seeds are selected for marking for each operating speed. The simulation results are shown in Table 3. The effect diagram needs to be manually marked, where the red dotted line is the long axis of soybeans; the yellow dotted line is the horizontal reference line; and the gray dotted line is the center reference line.

[0139] Table 3 EDEM virtual simulation correction effect

[0140]

[0141] Table 3 shows the migration postures, qualified rates of inclination angles, and qualified rates of seed offsets of soybean seeds at operating speeds of 13 km / h to 16 km / h. The simulation results show that under the action of the correction element, the long axis of the soybean seeds located in the seed cavity gradually tends to be perpendicular to the migration direction. However, the correction process may fail. For example, in the n 2 test at an operating speed of 15 km / h, the long axis was not visualized. This may be because the seeds were just incorporated into the seed cavity and the speed was too fast, resulting in increased disorder, so that the seeds were not adjusted by the limiting block to visualize the long axis. The above results further verify the key role of the crosswise height in improving the consistency and stability of seed dropping, and the optimized crosswise height helps to reduce the deviation of the seed dropping effect caused by inconsistent seed conveying postures.

[0142] 4 Bench tests

[0143] 4.1 Test conditions

[0144] The correction test of the belt-type high-speed seed guiding device was carried out on August 14, 2024, in the sowing equipment laboratory of the College of Engineering, Heilongjiang Bayi Agricultural University. The test device was mainly composed of a JPS-16 type computer vision metering seeder test bench, a PCO.dimaxCS3 type high-speed camera (German pco,dimaxcs high-speed camera, Nikon lens, the image capture program is Camware, and the image processing program is TEMA), a modified air-suction type soybean precision metering seeder, a correction element, and a PC (HP company, USA), etc. To facilitate capturing the grain posture correction during the seed conveying process, the original outer shell of the seed guiding belt was made transparent using 3D printing technology, as Fig.14 shown. The metering seeder and the belt-type seed guiding device were fixed on the test bench. During the test, the seedbed belt moved in the opposite direction relative to the metering seeder and the seed guiding belt to simulate the forward movement state of the seeding machine. The fuel injection pump sprayed oil on the seedbed belt, and the soybean grains fell from the seed dropping port of the seed guiding device onto the seedbed belt coated with an oil layer

[29] .

[0145] 4.2 Test methods

[0146] From the analysis of the correction degree of the grain posture by the above crosswise height of the correction stripes, it can be seen that the stability and consistency of the grain posture are related to the crosswise height of the correction stripes and the forward speed. Therefore, in this study, the crosswise height of the correction stripes and the forward speed were selected as test factors to test the grain posture. Different correction elements with different crosswise heights were obtained using 3D printing technology, and the length and width of the correction elements remained unchanged, as Fig.15 shown. Through preliminary pre-tests, a 27-hole metering disc was selected as the test metering disc, and the number of seed conveying chambers of the seed guiding belt was 78, which could also meet the highest-speed stable operation of the belt-type seed guiding device.

[0147] 4.3 Post-processing of grain posture changes and trajectory tracking

[0148] During the trajectory measurement process, in order to obtain the changes in the posture and movement trajectory of the grains during high-speed seeding in this study, high-speed cameras were placed at different positions for shooting. The images of the grain movement trajectories collected by the high-speed camera were stored in the computer in real time and saved as .avi format video files after the experiment. TEMA control software was used to track the video files and extract the positions of the grains in different frames before and after the correction of the grains. Fig.16 As shown, it includes the stage where the grains are not corrected, and the grains are closely attached to the seed belt shell for seed transport; the stage where the grains are being corrected, and the grains will be corrected and offset when they contact the correction element, and the grains will fall to the correct seed transport position through contact collision; the stage where the grains are corrected, the grains are pushed downward by the seed belt paddles, and the positions of the grains in the seed cavity are fixed. At this time, the grains remain in a stable state, which proves that the grains have completed the correction and achieved a stable seed transport process.

[0149] 5 Test results and analysis

[0150] 5.1 Comparative test

[0151] In order to verify whether the belt seed guide device has a correction element that affects the seed implantation effect, 3D printing was used to make a bench comparison test with and without a cross-grain correction element. The seeding height was set to 10mm, the cross-grain height was 1mm, and the operating speed was 13, 14, 15, and 16km / h respectively. Each group was tested 3 times and the average value was taken. The test results are as follows Fig.17 shown.

[0152] Fig.17 The attitude variation coefficient and plant spacing variation coefficient of the correction element with horizontal stripes are lower than those of the correction element without horizontal stripes, indicating that the correction element can correct the seed attitude in the seed delivery area, reduce the random collision of seeds in the seed cavity, and improve the sowing effect and sowing uniformity. Among them, the attitude variation coefficient and plant spacing variation coefficient of the correction element are more than 5% higher than those without the correction element.

[0153] 5.2 Verification test

[0154] By analyzing the sowing performance diagrams with and without the correction element, it can be seen that the correction element can significantly improve the stability of the seeds in the cavity and ensure the consistency of the seed placement posture. The low posture variation coefficient means that the seeds are transported in a stable posture in the seed guide device, so that the seed placement position and angle can be controlled, thereby improving the sowing accuracy; the low plant spacing variation coefficient indicates that the distance between adjacent seeds is more uniform. This consistency helps crops avoid overcrowding or oversparseness caused by uneven density during the later growth process, which ultimately helps to increase crop yields.

[0155] Based on the preliminary experiments, the seeding height of the belt-type seed guide device was determined to be 10 mm, the inclination angle was 79°, the height of the corrected horizontal grain was 1 mm, and the operating speed range was 13-16 km / h. Four repeated tests were conducted for each operating speed. 500 consecutive seeds were selected for each operating speed. The coefficient of variation of seed posture S was used as the coefficient of variation of seed posture. 3 , plant spacing variation coefficient S 4 Test as a test indicator.

[0156] The calculation of the attitude variation coefficient A must meet the conditions of S and Q before calculation. The calculation formula is:

[0157]

[0158] In the formula——σ 1 is the standard deviation of posture, mm;

[0159] μ 1 is the average posture value, mm.

[0160] The calculation formula of plant spacing variation coefficient is:

[0161]

[0162] Where ——σ 2 is the standard deviation of plant spacing, mm;

[0163] μ 2 is the average plant spacing, mm.

[0164] The seeding performance test data and the correction effect diagram taken by high-speed camera are summarized as shown in Table 4.

[0165] Table 4 Changes in sowing performance under high-speed video

[0166]

[0167] Through in-depth analysis of the sowing performance data and high-speed camera correction results in Table 4, as the operating speed gradually increases from 13km / h to 16km / h, the coefficient of variation of seed posture and plant spacing shows a significant upward trend. The coefficient of variation of seed posture increases from 13.75% to 19.04%. This change reveals that under high-speed working conditions, the centrifugal force and collision force of the seeds in the seed guide cavity increase, making it more difficult for the seed posture to remain stable; the coefficient of variation of plant spacing increases from 10.14% to 15.31%. Due to the increase in the instability of seed posture, the position accuracy of the seeds at the seeding point is reduced, which in turn affects the distance that the seeds fall into the soil. This variation increases the unevenness of the plant spacing of adjacent seeds and reduces the stability of the seeding effect. The results show that the correction element with a 1mm cross-grain height effectively improves the consistency of seeding to a certain extent, and verifies the consistency of the simulation test and the bench test results. In summary, the average value of the coefficient of variation of soybean seed posture is 16.45%, and the average value of the coefficient of variation of soybean plant spacing is 12.78%.

[0168] 6 Conclusion

[0169] (1) To address the problem of unstable seeding effect caused by inconsistent seed posture in the belt-type soybean high-speed seed guide device, a seed posture correction element was designed. The seed delivery trajectory was changed by contact collision. The force condition and seed delivery position of the seeds after the collision were analyzed to ensure that the seed maintained a stable position in the seed guide belt cavity. The working area size of the correction element was determined to be 38×12×3mm, and the transverse grain height was 1mm.

[0170] (2) Through simulation experiments, the correction effect of different horizontal grain heights (0.50-1.50 mm) of the correction element was deeply studied. Under the operating conditions of 13-16 km / h, it was found that the seed posture fluctuation was the smallest at a horizontal grain height of 1.00 mm, which could make the long axis of the seed perpendicular to the migration direction. The average inclination qualified rate was 95.7%, and the average seed offset qualified rate was 98.2%.

[0171] (3) The bench test results show that at different operating speeds, the belt-type seed guide device equipped with a correction element significantly reduces the coefficient of variation of the posture and the coefficient of variation of the plant spacing. In particular, after installing the correction element with a cross-grain height of 1 mm, the coefficient of variation of the grain posture and the coefficient of variation of the plant spacing were kept below 20% and 16%, respectively, proving the effectiveness of the correction element in improving the sowing accuracy. The correction element of the belt-type soybean seed guide device designed by the present invention can meet the requirements of high-speed precision sowing operations.

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Claims

1. A seed posture correction element of a belt-type soybean high-speed seed guiding device, characterized in that: The grain posture correction element is used to correct the seed posture in the correction area of ​​the belt-type soybean high-speed seed guide device. The grain posture correction element is a strip-shaped block, and the front and back sides of the correction element are respectively provided with shell fixing columns, which are used to firmly fix the correction element to the shell fixing hole. The correction element relies on transverse stripes for posture correction, and one side surface thereof is provided with five-order parallel transverse stripes, and every three-order transverse stripes correspond to a seed cavity, thereby increasing the correction range.

2. The seed posture correction element of the belt-type soybean high-speed seed guiding device according to claim 1 is characterized in that: The selection of the horizontal stripe height h should take into account the distance between the shell and the paddle, and it is only necessary to achieve the correction effect; the correction element length L = 3N, the distance between the two outermost horizontal stripes L0 = 0.9L, L0 = N / 2; L0 is the actual working length, and N is the number of cavities.

3. The seed posture correction element of the belt-type soybean high-speed seed guiding device according to claim 1 or 2, characterized in that: A boss is provided on the surface corresponding to the side surface provided with the five-order parallel transverse lines, and the boss is used to cooperate with the insertion hole at the corresponding position of the seed guide device shell.

4. A design method for a seed posture correction element of a belt-type soybean high-speed seed guiding device, characterized in that: The implementation process of the method is: Correction element parameter determination The seeds are transported to the correction element by the thrust of the paddle, and the direction of the long axis of the seeds is adjusted by contact and collision, ensuring that each seed is visualized with its long axis and is transported perpendicular to the seeding direction, so that it can be accurately delivered in a uniform posture at the seeding port. The correction element is the core element for correcting the posture of the seeds. The material and the height of the horizontal grain directly affect the position of the seeds in the seed cavity of the seed transport belt. The correction element must ensure that the seeds do not deform significantly after contact with the correction element, and the displacement after collision should not be too large. It is made of nitrile rubber (NBR) material with high stability and impact resistance, excellent wear resistance and heat resistance. The material characteristic parameters are as follows: Mooney viscosity / MU is 82, hardness / Shore A is 74, and compression permanent deformation / % is 23; The selection of the horizontal grain height h should take into account the distance between the shell and the paddle, L = 3N, L0 = 0.9L, L0 = N / 2; L is the length of the correction element, mm; L0 is the actual working length, mm, and N is the number of cavities; Mechanical analysis of the correction process Based on the relationship between the correction performance of the correction element and the posture change of the seed in the seed cavity, a seed mechanical model during the correction process was established, and the force condition of the seed during the correction stage was analyzed. The collision process of the seed was divided into the collision deformation stage and the collision recovery stage. The soybean was regarded as a uniform, isotropic ellipsoid with a very small contact area. The contact force condition was non-common, and the deformation amount during the contact process was much smaller than the size of the soybean. The movement direction of the soybean was perpendicular to the placement of the seed conveyor belt. The relationship between the transverse grain height h of the correction element and the coordinates of the soybean seeds in the correction area after correction is obtained through mechanical analysis of the correction process.

5. The design method of a seed posture correction element of a belt-type soybean high-speed seed guiding device according to claim 4 is characterized in that: The specific process of mechanical analysis of the correction process is: Seed movement analysis The deformation process of soybean collision with the correction element is analyzed, the force F1 of the collision between the seed and the correction element, the thrust F0 of the paddle on the seed, and the support force F N , the friction force on the grain and the grain's own gravity G, the angle α between the collision force and the y-axis, and the installation angle β of the seed guide. The center of the grain is taken as the coordinate origin o, the x-axis perpendicular to the grain's movement direction, and the y-axis is used to establish a rectangular coordinate system xoy; From the collision analysis between soybean and correction element, it can be known that if we want to ensure the stable seed delivery in the seed cavity, ω has only two results of 0° or 90°; according to D'Alembert's principle, the mechanical equation of soybean seed at this time is: Where F f ——Contact friction between soybean and correction element, N; m——soybean mass, g; k——friction coefficient of contact surface; Formula (1) represents the balance between the contact friction between the seed and the correction element and other forces during the collision process; the coordinates (x0, y0) of the soybean seed after the collision are obtained as follows: Where x is the displacement of the pick, mm; a——length of the long axis of soybean seeds, mm; x0——the horizontal coordinate of the plane where the seed is located; y0——the vertical coordinate of the plane where the seed is located; In order to ensure that the seed can correct its posture with the minimum energy consumption, the angle α between the force F1 of the seed collision with the correction element and the Y axis should be minimized; at the same time, the horizontal component of the speed of the paddle hitting the seed during seeding should be equal in magnitude and opposite in direction to the forward working speed of the machine, ensuring that its speed in the horizontal direction is zero. At this time, the thrust F0 on the seed is: Where V0 is the initial velocity of soybean, mm / s; V1——pick speed, mm / s; dV0 / dt——V0 derivative, mm / s 2 ; Combining formula (3) to get By analyzing the speed conversion relationship between the machine operating speed and the linear speed of the seed guide belt, it can be known that the relationship between the angle μ between the linear speed of the paddle at the seeding port and its horizontal component speed and the inclination angle β of the seed guide belt is: Where V2 is the machine operating speed, km / h; γ——the angle between the pulley line and the seeding point, γ=166.5°; Integrating equations (2), (4), and (5), the coordinates of soybean seeds at the time of transplanting are: Where b is the length of the short axis of soybean seeds, mm; Collision deformation process The deformation and recovery stages of the collision between the seed and the correction element were further analyzed. The recovery coefficient e in the deformation process of the soybean-correction element collision was n , e τ = 0, the contact area size between the seed and the correction element is Where c is the contact area size, mm; R e ——equivalent relative radius of curvature, mm; R1 ’ ——Maximum radius of curvature of the corrective element in the contact area, mm; R1 ” ——Minimum radius of curvature of the corrective element in the contact area, mm; R2 ’ ——The maximum curvature radius of the seed in the contact area, mm; R2 ” ——Minimum curvature radius of the seed in the contact area, mm; E1——elastic modulus of the correction element, Pa; E2——elastic modulus of soybean, Pa; K——constant determined by the principal radius of curvature; μ1——Poisson’s ratio of the corrective element; μ2——Poisson’s ratio of the grain; δ1——collision compression of rice; δ2——collision compression of threshing element; It can be seen from formula (7) that the contact area size c is positively correlated with the thrust F0 of the paddle on the seed, that is, the faster the rotation speed V1 of the seed guide belt, the greater the thrust of the paddle on the seed, and the greater the angle between the line connecting the contact point and the center of gravity of the soybean and the y-axis; the angle affects the component velocity and impulse generated when the seed collides. Since the displacement of the seed is limited when changing its posture, the seed may bounce repeatedly, so the height of the corrected cross grain is changed to reduce the occurrence of the bouncing problem; according to the Lagrange equation of collision, the seed angular velocity ω and the collision impulse I are calculated to analyze the motion trajectory of the object under collision or constraint conditions; to analyze whether the energy of the system is effectively utilized or converted, the relative total kinetic energy T* of the system is Where J is the moment of inertia of soybean, g·mm 2 ; The corresponding generalized impulse formula is Combining equations (8) and (9) to obtain another form of the collision Lagrange equation: Plastic collision has constraint conditions V An =V Aτ =0, we get It can be seen from formula (11) that the angular velocity of the seed is negatively correlated with the height h of the cross grain of the correction element. Therefore, in the collision deformation process, the choice of the cross grain height directly affects the seed posture correction effect. Not only is there enough energy to adjust the seed posture, but also the deformation energy stored in the correction element needs to be partially converted back to kinetic energy. Therefore, the collision recovery stage needs to be considered, that is, when the force at the contact point gradually decreases and the object begins to restore its original shape; Crash recovery process The recovery coefficient e of the seed and the correction element during the collision process is set to 0. In the collision recovery stage (e≠0), ω', V An '、V Aτ ' represents its generalized velocity, and its total kinetic energy is Similarly, integrating equation (12) into another form of the collision problem Lagrange equation yields Definition of collision restitution coefficient I' n =e n I n , I' τ =e τ I τ Solved When the collision between the seed and the correction element ends, the soybean seed will move in a uniform and stable state along with the paddle. Substituting equation (14) into equation (6), the coordinates (x0, y0) of the soybean in the correction area at this time are obtained as follows: According to formula (15), the coordinates of the soybean seeds after correction in the correction area are obtained. The position is negatively correlated with the corrected horizontal grain height. Experimental optimization is carried out based on the influence of different horizontal grain heights on the degree of seed deviation, and the horizontal grain height h of the final correction element is obtained.

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