Sharp-tooth-shaped small special-shaped seed clamping device, design method and integration method

Abstract

The invention relates to the technical field of agricultural breeding equipment, in particular to a sharp-tooth-shaped small special-shaped seed clamping device and a design method and an integration method.The sharp-tooth-shaped small special-shaped seed clamping device structurally comprises a steering engine, an electric clamping jaw, a seed collection camera, a clamping arm and a blade, the shape, thickness and size of an end effector are designed, active control is not needed, and the design method is simple. In the clamping process, the tail end deforms to generate clamping force, so that the sharp teeth at the tail end can be slightly embedded into seed coats, the clamping stability is improved, full-automatic low-loss clamping and transportation of miniaturized seeds are realized, the clamping efficiency and precision are improved, manpower is liberated, and the cost is greatly reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of agricultural breeding equipment, and particularly relates to a small-sized special-shaped seed clamping device with pointed teeth, as well as a design method and an integration method thereof. Background Technique

[0002] The seed clamping technology is a key technology widely used in fields such as seed slicing, sowing, and gene detection. Small-sized special-shaped seeds are tiny in volume and various in shape, and are prone to mechanical damage, making it more difficult to achieve effective clamping. This technology belongs to the field of micro-operations. Currently, it mainly relies on precise micro-force sensing, feedback, and control technologies, which have high requirements for both the detection and positioning system and the force control system, and the implementation cost is high.

[0003] The Chinese invention patent "A Grain Seed Slicing and Dyeing Device" (202310176724.0) uses a feeding mechanism and a material blocking mechanism to fix and convey seeds, and can process multiple seeds at one time to achieve the integration of seed slicing and dyeing. However, it lacks stability during the slicing process, and the seed posture is likely to change due to mechanical vibration during the operation; the Chinese utility model patent "An Agricultural Seed Slicing and Sampling Device" (202322437617.7) clamps seeds by driving a pressing plate to squeeze through a threaded rod. This method can prevent the seeds from shifting during the slicing process, but it is extremely easy to cause mechanical damage to the seeds during the pressing process. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a small-sized special-shaped seed clamping device with pointed teeth, as well as a design method and an integration method thereof, so as to solve the problems of insufficient clamping stability and easy damage to seeds in existing devices.

[0005] Based on the above purpose, the present invention provides a small-sized special-shaped seed clamping device with pointed teeth, including a servo motor, an electric gripper, a seed acquisition camera, a clamping arm, and a blade. The electric gripper is installed on the servo disc at the lower end of the servo motor through a connecting piece, and the servo motor changes the clamping posture of the electric gripper by rotating;

[0006] The seed acquisition camera is fixed on one side of the electric gripper and is used to acquire seed image information;

[0007] The end of the electric gripper is connected to the clamping arm, and the clamping arm includes a group of variable cross-section rods. The large end of the cross-section is fixed at the end of the electric gripper, and the small end of the cross-section is provided with a blade installation groove;

[0008] The blade is installed on the blade installation groove at the end of the clamping arm.

[0009] Preferably, the cross-section shape of the clamping arm is a rectangular cross-section, and the cross-section width changes linearly from the large end to the small end and changes with the length of the rod.

[0010] Preferably, the blade is in the shape of an inclined wedge with an inclined cutting edge.

[0011] The present invention also provides a design method for the above-mentioned small-sized special-shaped seed clamping device with pointed teeth, including the following steps:

[0012] According to the force at the end of the clamping arm and the cross-sectional change, select an axis with a smooth curvature to generate a uniform stress distribution inside the clamping arm, introduce the arc length parameter s of the axis, and the cross-sectional area satisfies along the axis where A0 and A1 are the cross-sectional areas of the smallest end and the largest end respectively, L is the arc length of the axis, calculate its stiffness characteristics according to the stiffness matrix of the clamping arm, and select the combination that makes the end of the clamping arm generate the maximum deflection and the minimum rotation angle in the horizontal direction, and use it as the final shape and material of the clamping arm.

[0013] Preferably, the stiffness matrix of the clamping arm is expressed as K = ∫∫∫B T DBdV by integrating over the entire unit volume V, where D is the elastic matrix, B is the geometric matrix representing the strain ε, expressed as:

[0014]

[0015] where the strain ε is the end deformation, ε = {ε u ε v ε w}, u, v, and w respectively represent the axial displacement, vertical and horizontal deflections, δ = {u i v i w i θ xi θ yi θ zi} represents the displacement matrix of the clamping arm in the local coordinate system, N u (x), N v (x), N w (x) represent the displacement shape functions, and x is the abscissa.

[0016] According to the particle size d ∈ [d0, d1] of the small special-shaped seeds, d includes the length, width and thickness of the seeds, the required minimum clamping force F0 satisfies f < F0 < F1, where f represents the clamping force when stable clamping is achieved within the specified range and the seeds will not break or be damaged, and f ∈ (f min , f max ), f min is the clamping force required when clamping seeds with a particle size of d0, f maxF is the clamping force required for clamping seeds with a particle size of d1, and F1 is the critical clamping force at which the seeds with a particle size of d1 break during clamping. According to the factors that affect the sharpness of the blade during the clamping process, the main factors are the blade edge angle and thickness. Considering that the influence of the edge angle on energy loss is much greater than that of the thickness, and designing the blade into a sharp tooth shape according to the required clamping force, two symmetrically distributed blades form a group, and a four-point clamping action is performed as the electric gripper moves. Compared with general clamping, it can significantly reduce mechanical damage to the seeds. In addition, the material selection needs to have high hardness, high wear resistance and certain toughness to withstand the friction on the blade during the clamping process. Surface coating treatment can extend the service life of the blade without significantly increasing the cost.

[0017] The present invention also provides an integration method for a small special-shaped seed clamping device with pointed teeth, including:

[0018] Integrate the small special-shaped seed clamping device with pointed teeth as described in any one of claims 1-3 into the integration system. There is a mechanical buckle above the small special-shaped seed clamping device with pointed teeth, and it is connected to the integration system by means of a connecting piece or directly through a perforation fixing method; the small special-shaped seed clamping device with pointed teeth is connected to the integration system by a cable. The cable includes a power line, a control line and a data line. The integration system is respectively connected to the seed acquisition camera, the servo motor and the electric gripper through a serial communication interface for transmitting control instructions. The system communicates with the host computer through the data line. The host computer realizes the acquisition, transmission and processing of seed image information, calculates the seed pose, plans the grasping path, and realizes the clamping and relaxation of the electric gripper through the real-time control system. The system controls the rotation of the servo motor through the PWM signal.

[0019] Advantages of the present invention:

[0020] 1) Invented a small special-shaped seed clamping device with pointed teeth, realizing the multi-functional integration operation of seed recognition, clamping and attitude adjustment;

[0021] 2) Through the pointed-tooth clamping device, the image recognition and the clamping device are linked. It can not only accurately identify the shape and attitude of the seeds, but also quickly adjust their directions. The degree of automation is high, greatly improving the processing efficiency of the seeds. Combined with the pointed-tooth clamping device, it is firmly clamped by the method of combining four-point clamping with the target coordinates, reducing mechanical damage to the seeds;

[0022] 3) The present invention can be integrated into a slicing machine system or other seed clamping systems. Description of the Drawings

[0023] To more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only those of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0024] Figure 1 It is the control flowchart of the small-sized special-shaped seed clamping device with pointed teeth according to the embodiment of the present invention;

[0025] Figure 2 It is the schematic diagram of the pointed-tooth clamping device according to the embodiment of the present invention;

[0026] Figure 3 It is the structural design drawing of the clamping arm according to the embodiment of the present invention;

[0027] Figure 4 It is the installation schematic diagram of the pointed-tooth clamping device according to the embodiment of the present invention;

[0028] Figure 5 It is the schematic diagram of the seed clamping state according to the embodiment of the present invention;

[0029] Figure 6 It is the specific structural schematic diagram of the slicer integration system according to the embodiment of the present invention.

[0030] The labels in the figure are:

[0031] 1. Acquisition camera; 2. Servo motor; 3. Pointed-tooth clamping device; 4. Installation groove; 5. Frame; 6. Moving bracket; 7. Parallel robotic arm; 8. Motor driver; 9. Seed transfer device; 10. Spacer; 11. Motor; 12. Base plate; 13. Synchronous belt module; 14. Driving rotating shaft; 15. Guide rail; 16. Slide block; 17. Control system; 18. Power supply; 19. Embedded controller; 20. Electric gripper; 21. Clamping arm; 22. Blade; 23. Seed; 24. Cable; 25. Buckle. Specific embodiments

[0032] To make the purpose, technical solutions and advantages of the present invention clearer and more understandable, the following further details the present invention in combination with specific embodiments.

[0033] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the present invention should have the ordinary meanings understood by those with ordinary skills in the field to which the present invention pertains. The "first", "second" and similar terms used in the present invention do not denote any order, quantity or importance, but are only used to distinguish different components. Words such as "comprising" or "including" mean that the elements or objects appearing before this word cover the elements or objects listed after this word and their equivalents, without excluding other elements or objects. Words such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Upper", "lower", "left", "right", etc. are only used to represent relative position relationships, and when the absolute position of the object being described changes, the relative position relationship may also change accordingly.

[0034] As shown in the embodiments such as Figure 2 、 3 、4, 5, and 6, the integrated system of the wheat seed slicer in this embodiment includes: a frame (5), a seed transfer device (9), a serrated clamping device (3), and a control system (17). The frame (5) includes a bottom plate (12) and a moving bracket (6). The bottom plate (12) is divided into a positioning and clamping area and an operating area. On the premise of facilitating the acquisition of seed images, a monochromatic dark color can be selected as the background, and seed samples can be randomly scattered in the positioning and clamping area; the moving bracket (6) is composed of a group of parallel support rods, and the support rods can form an angle of 60° with the horizontal plane, and are fixed on the synchronous belt module (13), and the motor (11) drives the synchronous belt module (13) to drive the moving bracket (6) to move.

[0035] The seed transfer device (9) in the embodiment includes a synchronous belt module (13), a parallel manipulator (7), and a motor (11). The synchronous belt module (13) is composed of a slider (16), a guide rail (15), and a driving rotating shaft (14). A semi-closed synchronous belt module can be selected, a gasket (10) is installed at the bottom, and it is fixed on the bottom plate (12). The synchronous belt module (13) is driven by the motor (11), and the driving rotating shaft (14) realizes the transmission of power and the synchronization of motion; the parallel manipulator (7) is installed below the moving bracket (6), and the manipulator (7) can move horizontally with the moving bracket (6), and a Delta parallel manipulator can be selected; the motor (11) is fixed on one side of the synchronous belt module (13), and a servo motor or a stepper motor can be selected, and a reducer can be installed to buffer the rotation speed of the motor (11), thereby controlling the movement of the synchronous belt module (13).

[0036] On the basis of the above embodiments, the present invention further describes the serrated clamping device. The serrated clamping device (3) includes a servo motor (2), an electric gripper (20), a seed collection camera (1), a clamping arm (21), and a blade (22). The servo motor (2) is fixed to the end of the robotic arm (7) through a connecting piece, and the servo motor (2) changes the clamping posture of the clamping device by rotating; the electric gripper (20) is installed on the steering wheel at the lower end of the servo motor (2) through a connecting piece, and the electric gripper (20) has a positioning and clamping function. A connecting piece is installed at the end of the electric gripper (20) for connecting the end effector; the seed collection camera (1) is fixed on one side of the electric gripper (20), and the collection lens is vertically downward, and can move arbitrarily in three-dimensional space along with the robotic arm (7) to collect seed image information; the clamping arm (21) is composed of a group of variable cross-section rods, the large end of the cross-section is installed on the connecting piece and fixed to the end of the electric gripper (20), and a thin blade installation groove (4) is opened at the small end of the cross-section for fixing the blade (22); the blade (22) is in the shape of an inclined wedge with an inclined cutting edge and is installed on the installation groove (4) at the end of the clamping arm (21); the processing method of the serrated clamping device (3) is selected as laser cutting processing technology. The cutting profile needs to be determined in advance. The position of the installation groove (4) required for the blade (22) is engraved with a laser beam to form the required installation groove (4). The cut is polished after cutting with sandpaper, and the cut is polished to make its surface smooth. The installation method of the blade (22) can be selected as welding or bonding. Considering the size of the workpiece and the installation dimensions, the more convenient bonding is adopted, and the bonding material can be selected as an epoxy adhesive with higher strength.

[0037] As Figure 1 shown is the control flow chart of the clamping device.

[0038] On the basis of the above embodiments, the present invention further describes the design method of the clamping arm and the blade. The design method of the clamping arm (21) and the blade (22) is as follows: According to the requirements of the clamping task, the clamping arm (21) is designed to be bent, which helps to adapt to objects of different shapes and sizes, provides a better clamping angle and contact area, and thus improves the clamping stability. According to the required clamping force, a smooth curvature axis is selected to generate a uniform stress distribution inside the clamping arm. The axis equation in the embodiment is: The parameter t determines the length and curvature of the axis. In this embodiment, t = 1.27. The geometric characteristics of the clamping arm (21) can be described as follows: The cross-sectional shape is a rectangular cross-section, and the cross-sectional width changes linearly from the large end to the small end and changes with the length of the rod. The arc length parameter s of the axis is introduced, and the cross-sectional area satisfies where A0 and A1 are the cross-sectional areas of the smallest end and the largest end respectively, and L is the arc length of the axis. In this embodiment, A0 = 18 mm 2、A1=36mm 2 , L=44.35mm, and the finite element analysis method is used to optimize the structural design by analyzing its stiffness characteristics. For the variable cross-section rod, its axial displacement and deflection are not linear functions of x. The finite element method of the uniform cross-section rod cannot obtain satisfactory results. In order to ensure the calculation accuracy, a high-order polynomial must be used to represent the interpolation function of the variable cross-section rod. Due to the particularity of the curved rod structure, its rotation angle in each direction can be represented by the linear displacement integral in different directions. Its axial displacement, vertical and horizontal deflection are defined as u, v, w. In practical applications, since one end is fixed, only the 6 degrees of freedom of the end unit need to be considered. The displacement matrix of the rod unit in the local coordinate is δ={u i v i w i θ xi θ yi θ zi}, according to the finite element theory of rod element, analyze its displacement shape function, and express its three displacement shape functions as N u (x), N v (x), N w (x), x is the horizontal axis. The rod unit is subjected to combined deformation of tension and bending. The deformation is small. Since the end of the rod is subjected to less force and the force area is more uniform, the influence of shear deformation caused by bending is ignored. The end deformation is ε = {ε u ε v ε w},in, Then the strain ε can be expressed by its geometric matrix [B] as Defining the elasticity matrix The required stiffness matrix can show its stiffness characteristics. The diagonal elements of the matrix represent the stiffness of the corresponding degrees of freedom. By comparing the elements, we can deeply understand the mechanical behavior of the structure when it is subjected to force. Based on the principle of virtual work, the stiffness matrix of the rod can be derived. By integrating over the entire unit volume V, it can be expressed as K = ∫∫∫B T DBdV, the material for making the clamping arm (21) is 45 steel with good mechanical properties and moderate hardness. The material selection includes but is not limited to the above materials. The model is imported into ANSYS WORKBENCH finite element simulation software for modal analysis, and its stiffness matrix is extracted as follows:

[0039]

[0040] The stiffness characteristics can be seen from the stiffness matrix. The maximum deflection and the minimum rotation angle are generated in the horizontal force direction (z-axis). By comparing with other rigid materials, it is effectively verified that the clamping arm can meet the clamping requirements under the said material; According to the statistics of small and irregular seeds, such as the particle size d of wheat seeds ∈ [2.85, 3.70], d includes the width and thickness of wheat seeds, and the minimum clamping force F0 required satisfies f < F0 < F1, where f represents the clamping force when stable clamping is achieved within the specified range and the seeds will not break or be damaged, and f ∈ (f min , f max ), f min is the clamping force required to clamp wheat seeds with a particle size of 2.85 mm, f max is the clamping force required to clamp wheat seeds with a particle size of 3.70 mm, and F1 is the critical clamping force when the 3.70-mm wheat seeds break. According to the factors that affect the sharpness of the blade (22) during the clamping process, mainly the blade edge angle and thickness, considering that the influence of the edge angle on energy loss is much greater than the thickness, and designing the blade (22) to be a sharp tooth shape according to the required clamping force. Two symmetrically distributed blades (22) form a group, and a four-point clamping action is performed as the electric gripper (20) moves. Compared with general clamping, it can significantly reduce the mechanical damage to the seeds. In addition, the material selection needs to have high hardness, high wear resistance, and certain toughness to withstand the friction on the blade during the clamping process. By performing surface coating treatment, the service life of the blade can be extended without significantly increasing the cost. The edge angle is set to 20°, and the thickness is set to 1.5 mm. The size selection includes but is not limited to the said parameters. The manufacturing material of the blade (22) is selected as SK-5 carbon tool steel with relatively high hardness. The material selection includes but is not limited to the said material.

[0041] The control system (17) of the embodiment includes a synchronous belt motor driver (8), an embedded controller (19), and a power supply (18). The synchronous belt motor driver (8) is installed on one side of the frame (5), connected to the embedded controller (19), and drives the rotation of the synchronous belt motor (11); the embedded controller (19), which can be implemented based on a single-chip microcomputer system, a microcontroller system, or an embedded computer system, is fixedly connected to one side of the frame (5), connected to the synchronous belt motor driver (8) through serial communication, and drives the movement of the synchronous belt (13) by driving the rotation of the motor (11); the embedded controller (19) is connected to the seed collection camera (1) through serial communication to collect and process seed image information, determine the seed pose, and plan the grasping path; the embedded controller (19) is respectively connected to the servo motor (2), the parallel manipulator (7), and the electric gripper (20) through serial communication interfaces; the embedded controller (19) controls the rotation of the servo motor (2) through PWM signals; the embedded controller (19) controls the movement of the parallel manipulator (7) and the clamping and relaxation of the electric gripper (20) by sending instructions through a real-time control system; the power supply (18) is fixed on one side of the frame (5) and supplies power to the seed collection camera (1), the parallel manipulator (7), the electric gripper (20), the synchronous belt motor (11), the motor driver (8), and the embedded controller (19) through power lines.

[0042] In the above implementation, the integration method of the pointed-tooth-shaped small special-shaped seed clamping device is as follows:

[0043] 1) The pointed-tooth-shaped clamping device (3) is provided with a mechanical buckle (25) and can be connected to the integration system by means of a connecting piece or directly by means of perforation fixation;

[0044] 2) The pointed-tooth-shaped clamping device (3) can be connected to the integration system through a cable (24); the cable (24) includes a power line, a control line, and a data line. The integration system can be respectively connected to the seed collection camera (1), the servo motor (2), and the electric gripper (20) through serial communication interfaces for transmitting control instructions. The system communicates with the upper computer through the data line. The upper computer collects, transmits, and processes seed image information, calculates the seed pose, plans the grasping path, and realizes the clamping and relaxation of the electric gripper (20) through a real-time control system. The system controls the rotation of the servo motor (2) through PWM signals;

[0045] 3) The integration system can be a seed slicer or other systems that need to clamp seeds.

[0046] Those of ordinary skill in the art should understand that the discussion of any of the above embodiments is only exemplary and is not intended to imply that the scope of the present invention is limited to these examples; under the concept of the present invention, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations in different aspects of the present invention as described above, which are not provided in detail for the sake of brevity. Any omission, modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A small-sized special-shaped seed clamping device with pointed teeth, characterized in that, It includes a servo, an electric gripper, a seed collection camera, a clamping arm and a blade. The electric gripper is installed on the steering wheel at the lower end of the servo through a connecting piece, and the servo changes the clamping posture of the electric gripper by rotating. The seed collection camera is fixed on one side of the electric gripper and is used to collect seed image information. The end of the electric gripper is connected to the clamping arm. The clamping arm includes a group of variable cross-section rods. The large end of the cross-section is fixed at the end of the electric gripper, and a blade mounting groove is opened at the small end of the cross-section. The blade is installed on the blade mounting groove at the end of the clamping arm.

2. The small special-shaped seed clamping device with pointed teeth according to claim 1, characterized in that, The cross-section shape of the clamping arm is a rectangular cross-section, and the cross-section width changes linearly from the large end to the small end and changes with the length of the rod.

3. The small special-shaped seed clamping device with pointed teeth according to claim 1, characterized in that, The blade is in the shape of an inclined wedge and has an inclined cutting edge.

4. A design method for the small-sized special-shaped seed clamping device with pointed teeth according to any one of claims 1-3, characterized in that, It includes the following steps: According to the force at the end of the clamping arm and the cross-section change, an axis with a smooth curvature is selected to produce a uniform stress distribution inside the clamping arm. The arc length parameter s of the axis is introduced, and the cross-sectional area satisfies along the axis where A0 and A1 are the cross-sectional areas of the minimum end and the maximum end respectively, L is the arc length of the axis. Calculate its stiffness characteristics according to the stiffness matrix of the clamping arm, and select the combination that makes the end of the clamping arm produce the maximum deflection and the minimum rotation angle in the horizontal direction, and use it as the final shape and material of the clamping arm.

5. The design method of the small special-shaped seed clamping device with pointed teeth according to claim 4, characterized in that, The stiffness matrix of the clamping arm is expressed by integrating over the entire element volume V as K = ∫∫∫B T DBdV, where D is the elasticity matrix, B is the geometric matrix representing the strain ε, expressed as: where the strain ε is the end deformation, ε = {ε u ε v ε w}, u, v, and w represent the axial displacement, vertical and horizontal deflections respectively, δ = {u i v i w i θ xi θ yi θ zi} represents the displacement matrix of the clamping arm in the local coordinate system, N u (x), N v (x), N w (x) represent the displacement shape functions, and x is the abscissa.

6. The design method of the small special-shaped seed clamping device with pointed teeth according to claim 4, characterized in that The design method further includes: According to the particle size d of the small anisotropic seeds, where d ∈ [d0, d1], and d includes the length, width, and thickness of the seeds, the required minimum clamping force F0 satisfies f < F0 < F1, where f represents the clamping force when stable clamping is achieved within the specified range and the seeds do not break or fail, and f ∈ (f min , f max ), f min is the clamping force required to clamp seeds with a particle size of d0, f max is the clamping force required to clamp seeds with a particle size of d1, and F1 is the critical clamping force at which seeds with a particle size of d1 break. The blades are designed to be sharp and serrated according to the required clamping force. Two symmetrically distributed blades form a group and perform a four-point clamping action as the electric gripper moves, and the blade surface is treated with a coating.

7. An integration method for a small special-shaped seed clamping device with pointed teeth, characterized in that, It includes: Integrate the spiky small special-shaped seed clamping device described in any one of claims 1-3 into the integrated system. A mechanical buckle is opened above the spiky small special-shaped seed clamping device, and it is connected to the integrated system by a connecting piece or directly by a perforation fixing method; the spiky small special-shaped seed clamping device is connected to the integrated system by a cable. The cable includes a power line, a control line and a data line. The integrated system is respectively connected to the seed collection camera, the servo and the electric gripper through a serial communication interface for transmitting control instructions. The system communicates with the upper computer through the data line. The upper computer realizes the acquisition, transmission and processing of seed image information, calculates the seed pose, plans the grasping path, and realizes the clamping and relaxation of the electric gripper through a real-time control system. The system controls the rotation of the servo through a PWM signal.

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