A flexible clamping and conveying mechanism for leafy vegetables and its design method

Abstract

The present application discloses a flexible clamping and conveying mechanism for leafy vegetables and a design method thereof, which relates to the technical field of agricultural machinery, and includes: a symmetrically arranged flexible clamping and conveying mechanism unit, wherein the flexible clamping and conveying mechanism unit is composed of a frame, a driving device and support wheels arranged at both ends of the frame, and a clamping module surrounding the frame; the frame is the skeleton of the entire clamping and conveying mechanism, which is used to fix the support wheels, the clamping module and the driving device, and the support wheels are used to support and guide the movement of the clamping module. The flexible clamping module is relatively independent of the conveying structure, which avoids the interference caused by the interaction between different clamping wheels and the conveyor belt in the traditional clamping conveyor belt method, and ensures the stable clamping and conveying of leafy vegetables. Moreover, by optimizing the shape parameters of the buckling beam, flexible clamping and conveying of leafy vegetables under different feed amounts can be achieved, thereby avoiding clamping damage during the mechanical harvesting process of leafy vegetables and completing low-damage and orderly harvesting of leafy vegetables.

Description

Technical Field

[0001] The present application relates to the technical field of agricultural machinery, and in particular to a flexible clamping and conveying mechanism for leafy vegetables and a design method thereof. Background Art

[0002] Leafy vegetables are fast-growing vegetables primarily characterized by their fresh green leaves, petioles, and stems. Examples include spinach and rapeseed, and they are an important part of our daily diet. Currently, harvesting leafy vegetables is primarily done manually, a laborious and time-consuming process that increases production costs. This process has severely impacted the development of the vegetable industry.

[0003] Some traditional leafy vegetable harvesting equipment can replace manual labor in extracting leafy vegetables from the soil, significantly reducing labor intensity and improving harvesting efficiency. For leafy vegetables, to facilitate post-harvest bundling and packaging, the extracted leafy plants need to be transported back a distance to achieve orderly harvesting. However, this method often uses a stubble-based, unordered harvesting method, which does not utilize post-harvest bundling and packaging, thereby increasing the workload of post-harvest leafy vegetable processing.

[0004] To solve the above problems, existing leafy vegetable harvesting machines are available that can achieve orderly harvesting, facilitating the bundling, packing and collection of harvested leafy vegetables. However, due to the tender and juicy stems of leafy vegetables, they are easily damaged during the orderly clamping and transportation process. Summary of the Invention

[0005] In order to solve the above technical problems, this application proposes the following technical solutions:

[0006] In the first aspect, an embodiment of the present application provides a flexible clamping and conveying mechanism for leafy vegetables, comprising: a symmetrically arranged flexible clamping and conveying mechanism unit, wherein the flexible clamping and conveying mechanism unit is composed of a frame, a driving device and support wheels arranged at both ends of the frame, and a clamping module surrounding the frame; the frame is the skeleton of the entire clamping and conveying mechanism, which is used to fix the support wheels, clamping module and driving device, and the support wheels are used to support and guide the movement of the clamping module.

[0007] In one possible implementation, the clamping module is mainly composed of a clamping plate, a flexible buckling beam, a supporting plate, a height difference fastener, and a universal rotating base; the clamping plate is fixedly connected to the working end of the flexible buckling beam for clamping leafy vegetables; the flexible buckling beam is arranged in a symmetrical manner, and its supporting end is fixedly connected to the supporting plate, and each flexible buckling beam is composed of two sections of unit beams of specific shapes connected in series; the supporting plate is connected to the universal rotating base through a height difference fastener; the height difference fasteners are used alternately to form connections with different height differences between the supporting plates and the universal rotating base of adjacent clamping modules, and adjacent clamping plates have a staggered layout to avoid gaps between adjacent clamping plates from clamping the stems of leafy vegetables; the universal rotating bases are connected in series in sequence to form a closed transmission link, which rotates smoothly along the guide groove of the frame.

[0008] In a possible implementation, the driving device includes a driving wheel and a driving motor, the driving wheel is arranged on the frame, the rotation output end of the driving motor is fixedly connected to the driving wheel, and the driving motor is arranged on a motor fixing frame.

[0009] In a possible implementation, the frame is provided with a guide groove for accurately guiding the clamping module to move along a predetermined route.

[0010] In a second aspect, an embodiment of the present application provides a method for designing a flexible clamping and conveying mechanism for leafy vegetables, wherein the method comprises:

[0011] Based on the relationship between the deadweight and clamping force of leafy vegetables at different feeding amounts, the minimum clamping force required to achieve stable clamping of leafy vegetables at different feeding amounts was determined;

[0012] When the leafy vegetable flexible clamping and conveying mechanism clamps and conveys leafy vegetables of different feed amounts, under the reaction force of the minimum clamping force, each unit beam of the buckled beam in the clamping module of the leafy vegetable flexible clamping and conveying mechanism undergoes a deformation that satisfies the Euler-Bernoulli beam equation, thereby obtaining the Euler-Bernoulli beam equation of the unit beam;

[0013] A global coordinate system is established with the contact point between the axis of the buckled beam and the load-bearing plate in the clamping module as the origin, the positive direction of the x-axis is parallel to the load-bearing plate and horizontally points to the right, and the positive direction of the y-axis is perpendicular to the load-bearing plate and points to the clamping plate;

[0014] With reference to the global coordinate system, a local coordinate system is established for each unit beam. The origin of the local coordinate system coincides with the starting point of the unit beam. The local coordinate system of the first unit beam coincides with the global coordinate system. The local coordinate system of the second unit beam is deflected relative to the global coordinate system. The deflection angle is equal to the change angle of the working end of the first unit beam.

[0015] According to the geometric relationship between the global coordinate system and the local coordinate system, the spatial motion equilibrium equation and the static equilibrium equation generated by the working end of the buckled beam are derived. The system of equations consisting of the Euler-Bernoulli beam equation, the spatial motion equilibrium equation and the static equilibrium equation is solved to obtain the clamping force generated by the working end of the buckled beam under different feed amounts of leafy vegetables.

[0016] The shape parameters of the unit beam were iteratively optimized, and the component of the clamping force in the y-axis direction at the working end of the buckled beam under different feeding amounts of leafy vegetables was set as the goal of optimization design to be equal to the minimum clamping force, thus obtaining a flexible buckled beam structure that meets the stable clamping conditions.

[0017] In a possible implementation, the unit beam of the buckled beam uses an axis to represent the overall shape, and uses a polynomial function to describe its specific shape, and its initial shape is:

[0018] φ i (s)=a i +b i s+c i s 2 +d i s 3 (0≤s≤L i )

[0019]

[0020]

[0021] Where i represents the i-th unit beam, L i is the length of the i-th unit beam, s is the length of a point on the i-th unit beam, φ i (s) is the angle between the tangent line of the i-th unit beam at the beam length s and the x-axis, a i 、b i 、c i and d i is the shape parameter of the i-th unit beam, x i (s) is the horizontal coordinate of the i-th unit beam in the Cartesian coordinate system when the beam length is s, and y i (s) is the ordinate of the i-th unit beam in the Cartesian coordinate system at the beam length s, and ξ is the variable in the definite integral calculation.

[0022] In a possible implementation, the deformation of the unit beam of the buckled beam that satisfies the Euler-Bernoulli beam equation is:

[0023]

[0024]

[0025]

[0026]

[0027] Where E is the elastic modulus of the unit beam material, I is the section moment of inertia of the unit beam, is the angle between the i-th unit beam and the x-axis at the beam length s after deformation, f xi is the clamping force component in the x-axis direction of the working end of the i-th unit beam, f yi is the clamping force component in the y-axis direction of the working end of the i-th unit beam, Δα i (s) is the angle difference of the i-th unit beam at the beam length s after deformation, Δx i (s) is the displacement of the i-th unit beam in the x-axis direction at the beam length s after deformation, Δy i (s) is the displacement of the i-th unit beam in the y-axis direction at the beam length s after deformation.

[0028] In one possible implementation, the spatial motion equilibrium equation generated by the working end of the buckled beam is:

[0029]

[0030] Δx1(L1)+Δx2(L2)cos|Δα1(L1)|+Δy2(L2)sin|Δα1(L1)|=0

[0031] Δy-[-Δy1(L1)-Δy2(L2)cos|Δα1(L1)|+Δx2(L2)sin|Δα1(L1)|]=0

[0032] Where Δy is the displacement of the working end of the buckled beam in the y-axis direction under different feed amounts.

[0033] In one possible implementation, the static equilibrium equation generated at the working end of the buckled beam is:

[0034] f y1 -[f y2 cos|Δα1(L1)|+f x2 sin|Δα1(L1)]=0

[0035] f x1 -[f x2 cos|Δα1(L1)|-f y2 sin|Δα1(L1)]=0

[0036]

[0037] Where M is the moment at the connection between the two element beams.

[0038] In a possible implementation, the optimization model for iteratively optimizing the shape parameters of the unit beam is:

[0039]

[0040] Wherein, F is the minimum clamping force under different feed amounts.

[0041] In the embodiments of this application, the flexible gripping module is relatively independent of the conveying structure, avoiding the interference caused by the interaction between different gripping wheels and the conveyor belt in traditional gripping conveyor belts, ensuring stable gripping and conveying of leafy vegetables. Furthermore, by optimizing the shape parameters of the buckled beam, flexible gripping and conveying of leafy vegetables can be achieved at different feed rates, avoiding gripping damage during mechanical harvesting and achieving low-damage, orderly harvesting of leafy vegetables. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 A schematic diagram of the structure of a flexible gripping and conveying mechanism for leafy vegetables provided in an embodiment of the present application;

[0043] Figure 2 A schematic diagram of the structure of the clamping module provided in an embodiment of the present application;

[0044] Figure 3 A schematic diagram of a design method for a flexible gripping and conveying mechanism for leafy vegetables provided in an embodiment of the present application;

[0045] Figure 4 A schematic diagram of the stress and deformation of a buckled beam provided in an embodiment of the present application;

[0046] Figure 1-4 In the symbol, it is represented as:

[0047] 1-frame, 2-support wheel, 3-clamping module, 4-driving wheel, 5-driving motor, 31-clamping plate, 32-flexible buckling beam, 33-bearing plate, 34-height difference fastener, 35-universal rotating base. DETAILED DESCRIPTION

[0048] The present invention will be described below with reference to the accompanying drawings and specific implementation methods.

[0049] See also Figure 1 The flexible clamping and conveying mechanism for leafy vegetables provided in this embodiment includes: a symmetrically arranged flexible clamping and conveying mechanism unit, which consists of a frame 1, a driving device and support wheels 2 arranged at both ends of the frame 1, and a clamping module 3 surrounding the frame 1; the frame 1 is the skeleton of the entire clamping and conveying mechanism, which is used to fix the support wheels 2, the clamping module 3 and the driving device, and the support wheels 2 are used to support and guide the movement of the clamping module 3.

[0050] The drive device includes a drive wheel 4 and a drive motor 5. The drive wheel 4 is mounted on the frame 1. The rotation output end of the drive motor 5 is fixedly connected to the drive wheel 4. The drive motor 5 is mounted on a motor mounting bracket. The frame 1 is provided with a guide groove for accurately guiding the clamping module 3 to move along a predetermined path.

[0051] See also Figure 2 The clamping module 3 is mainly composed of a clamping plate 31 , a flexible buckling beam 32 , a bearing plate 33 , a height difference fastener 34 , and a universal rotating base 35 .

[0052] The clamping plate 31 is fixedly connected to the working end of the flexible buckling beam 32 and is used to clamp leafy vegetables; the flexible buckling beam 32 is arranged in a symmetrical manner, and its supporting end is fixedly connected to the bearing plate 33. Each flexible buckling beam 32 is composed of two unit beams of a specific shape connected in series.

[0053] The supporting plate 33 is connected to the universal rotating base 35 through the height difference fasteners 34. The height difference fasteners 34 are used alternately to form connections with different height differences between the supporting plates 33 and the universal rotating base 35 of adjacent clamping modules 3. The adjacent clamping plates 31 have a staggered layout to avoid the gaps between adjacent clamping plates 31 from clamping the stems of leafy vegetables.

[0054] The universal rotating bases 35 are connected in series in sequence to form a closed transmission chain, and rotate smoothly along the guide groove of the frame 1.

[0055] Corresponding to the flexible clamping and conveying mechanism for leafy vegetables provided in the above embodiment, the present application also provides an embodiment of a design method for a flexible clamping and conveying mechanism for leafy vegetables.

[0056] See also Figure 3 The design method of the flexible gripping and conveying mechanism for leafy vegetables provided in this embodiment includes:

[0057] S101, based on the relationship between the dead weight and clamping force of leafy vegetables at different feeding amounts, determining the minimum clamping force required to achieve stable clamping of the leafy vegetables at different feeding amounts.

[0058] S102, when the leafy vegetable flexible clamping and conveying mechanism clamps and conveys leafy vegetables with different feed amounts, under the reaction force of the minimum clamping force, each unit beam of the buckled beam in the clamping module of the leafy vegetable flexible clamping and conveying mechanism undergoes a deformation that satisfies the Euler-Bernoulli beam equation, thereby obtaining the Euler-Bernoulli beam equation of the unit beam.

[0059] S103, establish a global coordinate system with the contact point between the axis of the buckled beam and the carrier plate in the clamping module as the origin, the positive direction of the x-axis parallel to the carrier plate and horizontal to the right, and the positive direction of the y-axis perpendicular to the carrier plate and pointing to the clamping plate, such as Figure 4 shown.

[0060] S104, with reference to the global coordinate system, establish a local coordinate system for each unit beam, the origin of the local coordinate system coincides with the starting point of the unit beam, the local coordinate system of the first unit beam coincides with the global coordinate, and the local coordinate of the second unit beam is deflected relative to the global coordinate, and the deflection angle is equal to the change angle of the working end of the first unit beam.

[0061] S105, based on the geometric relationship between the global coordinate system and the local coordinate system, the spatial motion equilibrium equation and the static equilibrium equation generated by the working end of the buckled beam are derived, and the set of equations composed of the Euler-Bernoulli beam equation, the spatial motion equilibrium equation and the static equilibrium equation are solved to obtain the clamping force generated by the working end of the buckled beam under different feeding amounts of leafy vegetables.

[0062] S106, iteratively optimize the shape parameters of the unit beam, and set the component of the clamping force of the working end of the buckled beam under different feeding amounts of leafy vegetables in the y-axis direction equal to the minimum clamping force as the goal of the optimization design, to obtain a flexible buckled beam structure that meets the stable clamping conditions.

[0063] In this embodiment, the unit beam of the buckled beam uses an axis to represent the overall shape, and uses a polynomial function to describe its specific shape. Its initial shape is:

[0064] φ i (s)=a i +b i s+c i s 2 +d i s 3 (0≤s≤L i )

[0065]

[0066]

[0067] Where i represents the i-th unit beam, L i is the length of the i-th unit beam, s is the length of a point on the i-th unit beam, φ i (s) is the angle between the tangent line of the i-th unit beam at the beam length s and the x-axis, a i 、b i 、c i and d i is the shape parameter of the i-th unit beam, x i (s) is the horizontal coordinate of the i-th unit beam in the Cartesian coordinate system when the beam length is s, and y i (s) is the ordinate of the i-th unit beam in the Cartesian coordinate system at the beam length s, and ξ is the variable in the definite integral calculation.

[0068] The deformation of the unit beam of the buckled beam that satisfies the Euler-Bernoulli beam equation is:

[0069]

[0070]

[0071]

[0072]

[0073] Where E is the elastic modulus of the unit beam material, I is the section moment of inertia of the unit beam, is the angle between the i-th unit beam and the x-axis at the beam length s after deformation, f xi is the clamping force component in the x-axis direction of the working end of the i-th unit beam, f yi is the clamping force component in the y-axis direction of the working end of the i-th unit beam, Δα i (s) is the angle difference of the i-th unit beam at the beam length s after deformation, Δx i (s) is the displacement of the i-th unit beam in the x-axis direction at the beam length s after deformation, Δy i (s) is the displacement of the i-th unit beam in the y-axis direction at the beam length s after deformation.

[0074] The corresponding spatial motion equilibrium equation generated by the working end of the buckled beam is:

[0075]

[0076] Δx1(L1)+Δx2(L2)cos|Δα1(L1)|+Δy2(L2)sin|Δα1(L1)|=0

[0077] Δy-[-Δy1(L1)-Δy2(L2)cos|Δα1(L1)|+Δx2(L2)sin|Δα1(L1)|]=0

[0078] Where Δy is the displacement of the working end of the buckled beam in the y-axis direction under different feed amounts.

[0079] The static equilibrium equation corresponding to the working end of the buckled beam is:

[0080] f y1 -[f y2 cos|Δα1(L1)|+f x2 sin|Δα1(L1)]=0

[0081] f x1 -[f x2 cos|Δα1(L1)|-f y2sin|Δα1(L1)]=0

[0082]

[0083] Where M is the moment at the connection between the two element beams.

[0084] The optimization model for iteratively optimizing the shape parameters of the unit beam is:

[0085]

[0086] Wherein, F is the minimum clamping force under different feed amounts.

[0087] By optimizing the shape parameters of the unit beams that make up the buckled beam, the clamping force of the first unit beam in the y-axis direction is made to continuously approach the minimum clamping force, and finally the buckled beam shape parameters that meet the requirements of flexible clamping are obtained, thus realizing flexible structural design.

[0088] As can be seen from the above embodiments, the clamping and conveying mechanism of the present application adopts a symmetrical clamping and conveying mode of action. The frame serves as the skeleton of the entire conveying mechanism and is used to fix and install various auxiliary mechanisms. The clamping module is used to clamp and convey leafy vegetables. The support wheel is used to support and guide the movement of the clamping module. The clamping module, as the core component of the entire clamping and conveying mechanism, realizes flexible clamping of leafy vegetables by optimizing the shape parameters of the buckling beam. The drive device is used to drive the clamping module to rotate. The clamping and conveying mechanism of the present invention can avoid clamping damage during the mechanical harvesting process of leafy vegetables and realize flexible clamping and conveying of leafy vegetables under different feed amounts. Moreover, the clamping module and the conveying module are relatively independent, and the reliability is higher, which ultimately helps to achieve low-damage and orderly harvesting of leafy vegetables.

[0089] In the embodiments of the present application, "at least one" refers to one or more, and "more" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent the existence of A alone, the existence of A and B at the same time, and the existence of B alone. Among them, A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b and c can be represented by: a, b, c, ab, ac, bc, or abc, where a, b, c can be single or multiple.

[0090] The above description is merely a specific embodiment of the present application. Any person skilled in the art may easily conceive of variations or substitutions within the technical scope disclosed in this application, and such variations or substitutions shall be within the scope of protection of this application. The scope of protection of this application shall be subject to the scope of protection of the claims.

Claims

1. A flexible gripping and conveying mechanism for leafy vegetables, characterized in that: include: A symmetrically arranged flexible clamping and conveying mechanism unit, the flexible clamping and conveying mechanism unit consisting of a frame, a drive device and support wheels arranged at both ends of the frame, and a clamping module surrounding the frame; the frame is the skeleton of the entire clamping and conveying mechanism, used to fix the support wheels, clamping module and drive device, and the support wheels are used to support and guide the movement of the clamping module; The clamping module mainly consists of a clamping plate, a flexible buckling beam, a bearing plate, a height difference fastener, and a universal rotating base; the clamping plate is fixedly connected to the working end of the flexible buckling beam for clamping leafy vegetables; the flexible buckling beam is arranged in a symmetrical manner, and its supporting end is fixedly connected to the bearing plate, and each flexible buckling beam is composed of two sections of unit beams of a specific shape in series; the bearing plate is connected to the universal rotating base through a height difference fastener; the height difference fasteners are used alternately to form connections with different height differences between the bearing plates and the universal rotating base of adjacent clamping modules, and adjacent clamping plates have a staggered layout of high and low, so as to avoid the gaps between adjacent clamping plates from clamping the stems of leafy vegetables; the universal rotating bases are connected in series in sequence to form a closed transmission link, which rotates smoothly along the guide groove of the frame; The method for designing a flexible leaf vegetable clamping and conveying mechanism comprises: Based on the relationship between the deadweight and clamping force of leafy vegetables at different feeding amounts, the minimum clamping force required to achieve stable clamping of leafy vegetables at different feeding amounts was determined; When the leafy vegetable flexible clamping and conveying mechanism clamps and conveys leafy vegetables of different feed amounts, under the reaction force of the minimum clamping force, each unit beam of the flexible buckling beam in the clamping module of the leafy vegetable flexible clamping and conveying mechanism undergoes a deformation that satisfies the Euler-Bernoulli beam equation, thereby obtaining the Euler-Bernoulli beam equation of the unit beam; A global coordinate system is established with the contact point between the axis of the flexible buckling beam and the load-bearing plate in the clamping module as the origin, the positive direction of the x-axis is parallel to the load-bearing plate and horizontally points to the right, and the positive direction of the y-axis is perpendicular to the load-bearing plate and points to the clamping plate; With reference to the global coordinate system, a local coordinate system is established for each unit beam. The origin of the local coordinate system coincides with the starting point of the unit beam. The local coordinate system of the first unit beam coincides with the global coordinate system. The local coordinate system of the second unit beam is deflected relative to the global coordinate system. The deflection angle is equal to the change angle of the working end of the first unit beam. Based on the geometric relationship between the global coordinate system and the local coordinate system, the spatial motion equilibrium equation and the static equilibrium equation generated by the working end of the flexible buckling beam are derived. The system of equations consisting of the Euler-Bernoulli beam equation, the spatial motion equilibrium equation, and the static equilibrium equation is solved to obtain the clamping force generated by the working end of the flexible buckling beam under different leafy vegetable feed amounts. The shape parameters of the unit beam were iteratively optimized, and the component of the clamping force in the y-axis direction at the working end of the flexible buckling beam under different feeding amounts of leafy vegetables was set as the goal of optimization design to be equal to the minimum clamping force, thus obtaining a flexible buckling beam structure that meets the stable clamping conditions.

2. The flexible clamping and conveying mechanism for leafy vegetables according to claim 1, characterized in that: The driving device includes a driving wheel and a driving motor. The driving wheel is arranged on the frame. The rotation output end of the driving motor is fixedly connected to the driving wheel. The driving motor is arranged on a motor fixing frame.

3. The leafy vegetable flexible clamping and conveying mechanism according to claim 1, characterized in that: The frame is provided with a guide groove for accurately guiding the clamping module to move along a predetermined route.

4. The leafy vegetable flexible clamping and conveying mechanism according to claim 1, characterized in that: The unit beam of the flexible buckling beam uses the axis to characterize the overall shape, and uses a polynomial function to describe its specific shape. Its initial shape is: （ ） in, Indicates the Root unit beam, It is The length of the root element beam, It is The length of a point on the root element beam, It is The root unit beam is The tangent line at The angle between the axes, 、 、 and It is The shape parameters of the root element beam, It is The root unit beam is The horizontal coordinate in the Cartesian coordinate system, It is The root unit beam is The vertical coordinate in the Cartesian coordinate system, is the variable in the definite integral.

5. The leafy vegetable flexible clamping and conveying mechanism according to claim 4, characterized in that: The deformation of the unit beam of the flexible buckling beam that satisfies the Euler-Bernoulli beam equation is: in, is the elastic modulus of the element beam material, is the section moment of inertia of the unit beam, It is After the root unit beam is deformed, the beam length Place and The angle between the axes, It is Root element beam working end Clamping force component in the axial direction, It is Root element beam working end Clamping force component in the axial direction, It is After the root unit beam is deformed, the beam length The angle difference, It is After the root unit beam is deformed, the beam length Department The displacement in the axial direction, It is After the root unit beam is deformed, the beam length Department Displacement in the axial direction.

6. The leafy vegetable flexible clamping and conveying mechanism according to claim 5, characterized in that: The corresponding spatial motion equilibrium equation generated by the working end of the flexible buckling beam is: in, The working end of the flexible buckling beam under different feed rates Axial displacement.

7. The leafy vegetable flexible clamping and conveying mechanism according to claim 6, characterized in that: The static equilibrium equation corresponding to the working end of the flexible buckling beam is: in, is the moment at the connection between the two element beams.

8. The leafy vegetable flexible clamping and conveying mechanism according to claim 7, characterized in that: The optimization model for iteratively optimizing the shape parameters of the unit beam is: in, It is the minimum clamping force under the different feed amounts mentioned.

Images