Leaf vegetable constant-force clamping and conveying mechanism based on non-circular gear system and transmission ratio algorithm

Abstract

The invention relates to a leaf vegetable constant-force clamping and conveying mechanism based on a non-circular gear system and a transmission ratio algorithm. The clamping and conveying mechanism comprises a rack and a plurality of constant-force clamping modules installed on the rack. The constant-force clamping module comprises a non-circular gear system, the non-circular gear system comprises a front-end non-circular gear rotationally connected with the mounting shell and a rear-end non-circular gear, and the front-end non-circular gear is in transmission connection with the rear-end non-circular gear through a plurality of middle non-circular gears; a floating connecting rod is fixedly connected to the first rotating shaft, a floating clamping wheel is installed on the floating connecting rod, and the wheel face of the floating clamping wheel abuts against the inner side face of the clamping conveying belt. The constant-force clamping module serves as a core component of the whole clamping and conveying mechanism, and constant-force clamping of leaf vegetables is achieved through the design of a non-circular gear train. The driving module is used for driving the clamping belt to rotate. Clamping damage in the mechanical harvesting process of the leafy vegetables can be avoided, flexible clamping and conveying of the leafy vegetables under different feeding amounts are achieved, and low-damage orderly harvesting of the leafy vegetables is completed.

Description

Technical Field

[0001] The invention relates to the technical field of agricultural machinery, and in particular to the clamping and conveying of leafy vegetables, and specifically refers to a leafy vegetable constant force clamping and conveying mechanism based on a non-circular gear system and a transmission ratio calculation method. Background Art

[0002] Leafy vegetables such as spinach and rapeseed account for an important part of vegetable planting. At present, in agricultural production, the harvesting of leafy vegetables is mainly done manually, which is time-consuming and labor-intensive. In particular, with the increasing aging of the rural population and the shortage of labor, the cost of leafy vegetable harvesting has increased dramatically. The harvesting link has become an important factor restricting the development of leafy vegetable planting. Compared with mechanical operations such as sowing and fertilizing, the harvesting of leafy vegetables has become a shortcoming of mechanization. Therefore, it is urgent to realize the "machine replacement" operation and realize the mechanical harvesting of leafy vegetables.

[0003] At present, there are also some equipment for harvesting leafy vegetables, which can replace manual pulling of leafy vegetables from the soil, greatly reducing labor intensity and improving harvesting efficiency. However, for leafy vegetables, in order to facilitate bundling and packing after harvesting, the leafy vegetable plants pulled out of the soil need to be transported backward for a distance to achieve orderly harvesting. Since the stems of leafy vegetables are tender and juicy, they are easily clamped and damaged during the transportation process of orderly harvesting, resulting in the existing equipment for transporting leafy vegetable plants causing great damage to the leafy vegetables.

[0004] In view of the problem that leafy vegetables are easily damaged during the orderly harvesting process, it is urgent to invent a constant-force clamping and conveying mechanism for leafy vegetables so that the force applied during the harvesting process is less than the damaging force of the leafy vegetables, thereby achieving orderly and low-damage harvesting of leafy vegetables. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a constant force clamping and conveying mechanism for leafy vegetables based on a non-circular gear system and a transmission ratio algorithm, which provides a transmission ratio function for the design of the non-circular gear system. The constant force clamping and conveying mechanism realizes flexible and orderly clamping and conveying of leafy vegetables such as spinach, effectively reducing damage to the leafy vegetables during the conveying process.

[0006] The present invention is realized through the following technical scheme, which provides a leaf vegetable constant force clamping and conveying mechanism based on a non-circular gear system, comprising a frame, two clamping conveyor belts rotatably mounted on the frame, and a driving device for driving the clamping conveyor belts to rotate, a clamping and conveying channel is formed between the adjacent sides of the two clamping conveyor belts, and the inner sides of the two clamping conveyor belts are respectively provided with a plurality of constant force clamping modules mounted on the frame; the constant force clamping module comprises a mounting shell fixedly connected to the frame, and a non-circular gear system arranged on the mounting shell, the non-circular gear system comprises a front non-circular gear rotatably connected to the mounting shell through a first rotating shaft, and a rear non-circular gear rotatably connected to the mounting shell through a second rotating shaft, the front non-circular gear is transmission-connected to the rear non-circular gear through a plurality of intermediate non-circular gears;

[0007] A floating connecting rod extending toward the side where the clamping conveying channel is located is fixedly connected to the first rotating shaft, and a floating clamping wheel is installed on the floating connecting rod. The wheel surface of the floating clamping wheel presses against the inner side surface of the clamping conveying belt; the second rotating shaft is connected to the mounting shell through a torsion spring.

[0008] The leafy vegetable constant force clamping and conveying mechanism of the present scheme clamps the leafy vegetables by two clamping conveyor belts. The clamping conveyor belts rotate when driven by the driving device to convey the leafy vegetables through the clamping and conveying channel. The transmission connection between the front end non-circular gear and the rear end non-circular gear is realized by the intermediate non-circular gear. By setting a torsion spring, the second rotating shaft can rotate after receiving the torque transmitted by the intermediate non-circular gear. When the number of leafy vegetables in the clamping and conveying channel is large, the floating clamping wheel is displaced, and the first rotating shaft is driven to rotate by the floating connecting rod, and then the rear end non-circular gear and the second rotating shaft are driven to rotate by the intermediate non-circular gear, thereby realizing flexible clamping and conveying by utilizing the variability characteristics of the torsion spring.

[0009] As an optimization, the mounting shell is rotatably connected with an intermediate rotating shaft located between the first rotating shaft and the second rotating shaft, and the intermediate rotating shaft is fixed with an intermediate non-circular gear I meshing with the front non-circular gear and an intermediate non-circular gear II meshing with the rear non-circular gear. This optimization scheme uses a group of intermediate non-circular gears to achieve torque transmission, has a simple structure, and constitutes a variable transmission ratio non-circular gear system.

[0010] As an optimization, a preload adjustment screw is threadedly connected to the mounting shell, the axis of the preload adjustment screw is perpendicular to the axis of the torsion spring, one side force arm of the torsion spring is fixedly mounted on the second rotating shaft, and the other side force arm is pressed against the end face of the preload adjustment screw. By setting the preload adjustment screw, this optimization solution can adjust the preload force of the torsion spring when the preload adjustment screw is rotated.

[0011] As an optimization, the mounting shell includes an upper shell and a lower shell, the upper shell includes an upper top plate and two upper side plates extending downward from both ends of the upper top plate, the lower shell includes a lower bottom plate and two lower side plates extending upward from both ends of the lower bottom plate, the two upper side plates are respectively detachably fixed to the two lower side plates, and the two ends of the first rotating shaft and the two ends of the second rotating shaft are respectively rotatably connected to the upper top plate and the lower bottom plate through bearings. The mounting shell of this optimization solution is formed by the relative arrangement of the upper shell and the lower shell, has a simple structure, is easy to disassemble, and avoids interference with the rotation of the floating connecting rod.

[0012] The present scheme also provides a transmission ratio algorithm of the non-circular gear system of the above-mentioned leaf vegetable constant force clamping and conveying mechanism: according to the relationship between the dead weight and the clamping force of leaf vegetables with different feed amounts, the minimum clamping force required for stable clamping of leaf vegetables is obtained; during the harvesting process, when clamping leaf vegetables with different feed amounts, under the action of the minimum clamping force, due to the relationship between the action force and the reaction force, the floating clamping wheel drives the floating connecting rod to rotate a certain angle to generate an action torque; through the non-circular gear system, the torsion spring is driven to rotate and generate a corresponding angle, thereby generating a corresponding torque; according to the torque balance and the basic principle of gear transmission, it is determined that there is a functional relationship between the gear angles in the non-circular gear system, and the transmission ratio function of the non-circular gear system that meets the constant force clamping is obtained, so that the non-circular gear system can be designed based on the transmission ratio function.

[0013] The minimum clamping force required to clamp and transport leafy vegetables satisfies the following relationship:

[0014]

[0015] Where m is the mass of a single leafy vegetable, n is the amount of leafy vegetables fed, i.e., the number of leafy vegetables clamped, μ is the friction coefficient between the clamping belt and the leafy vegetables, ζ is the safety factor, and the ζ value reflects the relationship between the friction force and the weight of the clamped leafy vegetables. The larger the value, the greater the clamping force, and the more likely the leafy vegetables are to be damaged. The value range of ζ is [1.2,2]. n is the minimum clamping force required under different feeding amounts, where the subscript n represents the feeding amount of the clamped leafy vegetables and F is the minimum clamping force;

[0016] The torsion spring generates the corresponding torque:

[0017] M θ =kθ+M0

[0018] Where, k is the rotational stiffness of the torsion spring, θ is the torsion angle of the torsion spring, and M0 is the preload torque of the torsion spring;

[0019] The floating clamping wheel drives the floating connecting rod to rotate, generating a torque of:

[0020]

[0021] Where F is the minimum clamping force, L is the length of the floating link, is the initial attitude angle of the floating link, is the floating link rotation angle;

[0022] According to the torque balance and force transmission characteristics of the gear, the torque M θ and torque There is a transmission relationship:

[0023]

[0024] in, In a non-circular gear system, the torsion angle θ of the torsion spring and the rotation angle of the floating connecting rod are determined according to the basic principle of gear transmission. The first derivative of the functional relationship between , i is the transmission ratio of the non-circular gear system;

[0025] We get the differential equation:

[0026]

[0027] Solve the differential equation to obtain the transmission ratio function of the non-circular gear system that satisfies constant force clamping:

[0028]

[0029] The beneficial effects of the present invention are:

[0030] (1) The floating clamping wheel, floating connecting rod and non-circular gear system are provided to transmit the force exerted on the clamping conveyor belt by the leaf vegetables to the torsion spring. Therefore, when there are a large number of leaf vegetables in the clamping conveying channel, the clamping conveyor belt can push the floating clamping wheel to rotate the floating connecting rod to a certain angle, thereby realizing flexible clamping and conveying, thus avoiding damage to the leaf vegetables. The clamping and conveying mechanism of the present invention has a simple overall structure and strong versatility, and can realize flexible clamping and conveying of a variety of leaf vegetables.

[0031] (2) The constant force clamping and conveying structure design based on the non-circular gear system avoids the high cost and low reliability brought by the traditional control method. The mechanism and vegetables can achieve low-damage interaction, realizing low-damage clamping and conveying of leafy vegetables at different feed amounts. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the overall structure of the leaf vegetable constant force clamping and conveying mechanism based on the non-circular gear system of the present invention;

[0033] Figure 2 It is a structural schematic diagram of the constant force clamping module in the present invention;

[0034] Figure 3The relationship between the rotation angle and the transmission ratio curve of the non-circular gear system under the clamping force of 4N in the present invention;

[0035] Figure 4 This is a schematic diagram of the structure of the non-circular gear system under a clamping force of 4N in the present invention;

[0036] As shown in the figure:

[0037] 1. Support wheel, 2. Frame, 3. Clamping conveyor belt, 41. Driving device, 42. Driving wheel, 5. Constant force clamping module, 6. Tensioning wheel, 52. First rotating shaft, 56. Bearing, 511. Lower shell, 512. Fastener, 513. Upper shell, 531. Front non-circular gear, 532. Middle non-circular gear I, 533. Middle non-circular gear II, 534. Rear non-circular gear, 541. Torsion spring, 542. Preload adjustment screw, 551. Floating clamping wheel, 552. Floating connecting rod. DETAILED DESCRIPTION

[0038] In order to clearly illustrate the technical features of the present solution, the present solution is described below through specific implementation methods in conjunction with the accompanying drawings.

[0039] like Figure 1 The constant force clamping conveying mechanism for leafy vegetables based on a non-circular gear system is shown, comprising a frame 2, two clamping conveyor belts 3 rotatably mounted on the frame, and a driving device 41 for driving the clamping conveyor belts to rotate, a clamping conveying channel is formed between the adjacent sides of the two clamping conveyor belts, and a supporting wheel 1 and a driving wheel 42 respectively adapted to each clamping conveyor belt are also rotatably arranged on the frame, the clamping conveyor belt 3 is wound around the supporting wheel 1 and the driving wheel 42, and the axes of the supporting wheel and the driving wheel are both arranged vertically. The two driving wheels are respectively connected to the driving device 41, and the driving device 41 of this embodiment is a driving motor, which provides rotational power to the driving wheel through the driving motor, and when the driving wheel rotates, the clamping conveyor belt is driven to rotate.

[0040] The inner sides of the two clamping conveyor belts are respectively provided with a plurality of constant force clamping modules 5 mounted on the frame, and each constant force clamping module is arranged in sequence along the conveying direction of leafy vegetables. Specifically, the constant force clamping module 5 includes a mounting shell fixedly connected to the frame, and a non-circular gear system arranged on the mounting shell, the non-circular gear system includes a front non-circular gear 531 rotatably connected to the mounting shell through a first rotating shaft 52, and a rear non-circular gear 534 rotatably connected to the mounting shell through a second rotating shaft, the front non-circular gear is transmission-connected to the rear non-circular gear through a plurality of intermediate non-circular gears rotatably mounted on the mounting shell; the first rotating shaft and the second rotating shaft are rotatably connected to the mounting shell through bearings, the axes of the first rotating shaft and the second rotating shaft both extend vertically and are parallel to each other, the front non-circular gear is fixedly connected to the first rotating shaft, and the rear non-circular gear is fixedly connected to the second rotating shaft.

[0041] A floating connecting rod 552 extending toward the side where the clamping conveying channel is located is fixedly connected to the first rotating shaft 52, and a floating clamping wheel 551 is installed on the floating connecting rod 552. The floating clamping wheel 551 of this embodiment is installed at the movable end of the floating connecting rod 552. The supporting end of the floating connecting rod 552 is fixed to the first rotating shaft 52 and is coaxial with the front non-circular gear 531 of the non-circular gear system. The arc-shaped wheel surface of the floating clamping wheel is pressed against the inner side surface of the clamping conveying belt and is tangent to the inner side surface of the clamping conveying belt. The axis of the floating clamping wheel is parallel to the axis of the first rotating shaft. The floating clamping wheel is rotatably installed on the wheel axle, and the wheel axle is fixedly connected to the floating connecting rod to reduce the wear of the floating clamping wheel on the clamping conveying belt.

[0042] The second rotating shaft is connected to the mounting shell through a torsion spring 541. When the amount of leafy vegetables in the clamping and conveying channel is large, the second rotating shaft rotates forward along with the non-circular gear at the rear end, and the torsion spring is deformed under pressure. When the amount of leafy vegetables in the clamping and conveying channel is small, the elastic force of the torsion spring causes the second rotating shaft to rotate in the opposite direction, so that the floating clamping wheel maintains pressure on the clamping conveyor belt to ensure reliable clamping of the leafy vegetables.

[0043] The mounting shell is threadedly connected with a preload adjustment screw 542, the axis of which is perpendicular to the axis of the torsion spring, one side arm of the torsion spring is fixedly mounted on the second rotating shaft, and the other side arm of the torsion spring is pressed against the end face of the preload adjustment screw. The preload adjustment screw of this embodiment is mounted on the side wall of the mounting shell, and the preload adjustment screw is rotated to move toward or away from the torsion spring, thereby adjusting the preload force of the preload adjustment screw.

[0044] The mounting shell is rotatably connected with an intermediate rotating shaft located between the first rotating shaft and the second rotating shaft, and the intermediate rotating shaft is fixedly mounted with an intermediate non-circular gear I532 meshing with the front non-circular gear 531, and an intermediate non-circular gear II533 meshing with the rear non-circular gear 534. The non-circular gear system can also be composed of multiple pairs of meshing non-circular gears, which are fixedly mounted on the rotating shaft, the non-circular gears on adjacent rotating shafts mesh in sequence, and the coaxial non-circular gears rotate synchronously, forming a variable transmission ratio non-circular gear system.

[0045] The mounting shell includes an upper shell 513 and a lower shell 511. The upper shell 513 and the lower shell 511 are both U-shaped and arranged opposite to each other, and are used to support other components of the constant force clamping module. The upper shell 513 is fixedly connected to the frame 2 by bolts. Specifically, the upper shell 513 includes an upper top plate and two upper side plates extending downward from both ends of the upper top plate. The lower shell 511 includes a lower bottom plate and two lower side plates extending upward from both ends of the lower bottom plate. The two upper side plates are detachably fixedly connected to the two lower side plates by fasteners 512. The fasteners in this embodiment are connecting bolts. The two ends of the first rotating shaft and the two ends of the second rotating shaft are rotatably connected to the upper top plate and the lower bottom plate by bearings 56, respectively.

[0046] The frame is also equipped with a tensioning wheel 6 adapted to the clamping conveyor belt, and the tensioning wheel 6 is rotatably mounted on the tensioning shaft. An upper fixed seat located above the tensioning wheel 6 and a lower fixed seat located below the tensioning wheel 6 are fixed on the frame. The tensioning shaft passes through the upper fixed seat upward and the lower fixed seat downward. Long grooves for the tensioning shaft to move along the tensioning direction are respectively provided on the upper fixed seat and the lower fixed seat. The part of the tensioning shaft that passes through the upper fixed seat upward and the part that passes through the lower fixed seat downward are both threadedly connected with fastening nuts. The fastening nuts are tightened to fix the tensioning shaft. After loosening the fastening nuts, the position of the tensioning shaft is adjusted along the long groove to adjust the tensioning force of the clamping conveyor belt.

[0047] Spinach, as a typical representative of leafy vegetables, is selected as the specific object of this embodiment; this embodiment is based on the non-circular gear system transmission ratio algorithm of the leafy vegetable constant force clamping and conveying mechanism of the non-circular gear system:

[0048] According to the relationship between the deadweight and clamping force of spinach with different feeding amounts, the minimum clamping force required for stable clamping of spinach is obtained; when clamping spinach with different feeding amounts during the harvesting process, under the action of the minimum clamping force, the floating clamping wheel drives the floating connecting rod to rotate a certain angle due to the relationship between the action force and the reaction force, generating an action torque; through the non-circular gear system, the torsion spring is driven to rotate and generate a corresponding angle, generating a corresponding torque; according to the basic principle of torque balance and gear transmission, it is determined that there is a functional relationship between the gear angles in the non-circular gear system, and the transmission ratio function of the non-circular gear system that meets the constant force clamping is obtained, and the non-circular gear system is designed based on the transmission ratio function;

[0049] The minimum clamping force required to clamp and transport spinach satisfies the following relationship:

[0050]

[0051] Where m is the mass of a single leafy vegetable, n is the amount of leafy vegetables fed, i.e., the number of leafy vegetables clamped, μ is the friction coefficient between the clamping belt and the leafy vegetables, ζ is the safety factor, and the ζ value reflects the relationship between the friction force and the weight of the clamped leafy vegetables. The larger the value, the greater the clamping force, and the more likely the leafy vegetables are to be damaged. The value range of ζ is [1.2,2]. n is the minimum clamping force required under different feeding amounts, where the subscript n represents the feeding amount of the leafy vegetables, and F is the minimum clamping force. The minimum clamping force required to clamp spinach is 4N;

[0052] The torsion spring generates the corresponding torque:

[0053] M θ =kθ+M0

[0054] Where, k is the rotational stiffness of the torsion spring, θ is the torsion angle of the torsion spring, and M0 is the preload torque of the torsion spring;

[0055] The floating clamping wheel drives the floating connecting rod to rotate, generating a torque of:

[0056]

[0057] Where F is the minimum clamping force, L is the length of the floating link, is the initial attitude angle of the floating link, is the floating link rotation angle;

[0058] According to the torque balance and force transmission characteristics of the gear, the torque M θ and torque There is a transmission relationship:

[0059]

[0060] in, The torsion angle θ of the torsion spring and the rotation angle of the floating connecting rod in the non-circular gear system are determined based on the basic principle of gear transmission. The first derivative of the functional relationship between , i is the transmission ratio of the non-circular gear system;

[0061] We get the differential equation:

[0062]

[0063] Solve the differential equation to obtain the transmission ratio function of the non-circular gear system that satisfies constant force clamping:

[0064]

[0065] like Figure 3 As shown, the length of the floating link is L = 80 mm, and the initial attitude angle of the floating link is The rotational stiffness of the torsion spring is k = 0.0728 Nm / rad, and the transmission ratio curve of the non-circular gear system is obtained;

[0066] like Figure 4 As shown, based on the minimum clamping force of 4N, a corresponding transmission ratio non-circular gear system is designed to achieve constant force clamping of leafy vegetables with different feed amounts.

[0067] The clamping and conveying mechanism of the present invention adopts a symmetrical clamping and conveying action form. The frame serves as the skeleton of the entire conveying mechanism and is used to fix and install various auxiliary mechanisms. The clamping conveyor belt is used to clamp and convey leafy vegetables. The support wheel is used to support the clamping conveyor belt. The tensioning wheel is installed in the long groove of the frame to keep the clamping conveyor belt in a tensioned state. The constant force clamping module serves as the core component of the entire clamping and conveying mechanism. The constant force clamping of leafy vegetables is achieved through the design of a non-circular gear system. The driving module is used to drive the clamping belt to rotate. The clamping and conveying mechanism of the present invention can avoid clamping damage during the mechanical harvesting of leafy vegetables, realize flexible clamping and conveying of leafy vegetables under different feeding amounts, facilitate efficient and safe completion of centralized transportation after picking from the field, and realize low-damage and orderly harvesting of leafy vegetables.

[0068] Of course, the above description is not limited to the above examples. Technical features not described in the present invention can be achieved by or by using existing technologies, which will not be repeated here. The above embodiments and drawings are only used to illustrate the technical scheme of the present invention and are not limitations of the present invention. The present invention is described in detail with reference to the preferred implementation methods. Ordinary technicians in this field should understand that changes, modifications, additions or substitutions made by ordinary technicians in this technical field within the essential scope of the present invention do not depart from the purpose of the present invention, and should also fall within the scope of protection of the claims of the present invention.

Claims

1. A leaf vegetable constant force clamping and conveying mechanism based on a non-circular gear system, comprising a frame (2), two clamping conveyor belts (3) rotatably mounted on the frame, and a driving device (41) for driving the clamping conveyor belts to rotate, wherein a clamping and conveying channel is formed between the adjacent sides of the two clamping conveyor belts, and characterized in that: The inner sides of the two clamping conveyor belts are respectively provided with a plurality of constant force clamping modules (5) mounted on the frame; The constant force clamping module (5) comprises a mounting shell fixedly connected to a frame, and a non-circular gear system arranged on the mounting shell, the non-circular gear system comprising a front non-circular gear (531) rotatably connected to the mounting shell via a first rotating shaft (52), and a rear non-circular gear (534) rotatably connected to the mounting shell via a second rotating shaft, the front non-circular gear being transmission-connected to the rear non-circular gear via a plurality of intermediate non-circular gears; The first rotating shaft (52) is fixedly connected with a floating connecting rod (552) extending toward the side where the clamping conveying channel is located, and a floating clamping wheel (551) is installed on the floating connecting rod (552), and the wheel surface of the floating clamping wheel presses against the inner side surface of the clamping conveying belt; The second rotating shaft is connected to the mounting shell via a torsion spring (541).

2. The leaf vegetable constant force clamping and conveying mechanism based on a non-circular gear system according to claim 1 is characterized in that: The mounting shell is rotatably connected to an intermediate rotating shaft located between the first rotating shaft and the second rotating shaft, and the intermediate rotating shaft is fixedly provided with an intermediate non-circular gear I (532) meshing with the front non-circular gear (531), and an intermediate non-circular gear II (533) meshing with the rear non-circular gear (534).

3. The leaf vegetable constant force clamping and conveying mechanism based on a non-circular gear system according to claim 1 is characterized in that: A preload adjustment screw (542) is threadedly connected to the mounting shell, the axis of the preload adjustment screw is perpendicular to the axis of the torsion spring, one side force arm of the torsion spring is fixedly mounted on the second rotating shaft, and the other side force arm presses against the end face of the preload adjustment screw.

4. The leaf vegetable constant force clamping and conveying mechanism based on a non-circular gear system according to claim 1 is characterized in that: The mounting shell comprises an upper shell (513) and a lower shell (511), wherein the upper shell (513) comprises an upper top plate and two upper side plates extending downward from two ends of the upper top plate, and the lower shell (511) comprises a lower bottom plate and two lower side plates extending upward from two ends of the lower bottom plate, wherein the two upper side plates are detachably fixed to the two lower side plates, respectively, and the two ends of the first rotating shaft and the two ends of the second rotating shaft are rotatably connected to the upper top plate and the lower bottom plate respectively through bearings (56).

5. A transmission ratio algorithm of a non-circular gear system of a leaf vegetable constant force clamping and conveying mechanism according to any one of claims 1 to 5, characterized in that: According to the relationship between the deadweight and clamping force of leafy vegetables with different feeding amounts, the minimum clamping force required for stable clamping of leafy vegetables is obtained; when clamping leafy vegetables with different feeding amounts during the harvesting process, under the action of the minimum clamping force, the floating clamping wheel drives the floating connecting rod to rotate a certain angle due to the relationship between the action force and the reaction force, generating an action torque; through the non-circular gear system, the torsion spring is driven to rotate and generate a corresponding angle, generating a corresponding torque; according to the basic principle of torque balance and gear transmission, it is determined that there is a functional relationship between the gear rotation angles in the non-circular gear system, and the transmission ratio function of the non-circular gear system that meets the constant force clamping is obtained; The minimum clamping force required to clamp and transport leafy vegetables satisfies the following relationship: Where m is the mass of a single leafy vegetable, n is the amount of leafy vegetables fed, i.e., the number of leafy vegetables clamped, μ is the friction coefficient between the clamping belt and the leafy vegetables, ζ is the safety factor, and the ζ value reflects the relationship between the friction force and the weight of the clamped leafy vegetables. The larger the value, the greater the clamping force, and the more likely the leafy vegetables are to be damaged. The value range of ζ is [1.2,2]. n is the minimum clamping force required under different feeding amounts, where the subscript n represents the feeding amount of the clamped leafy vegetables and F is the minimum clamping force; The torsion spring generates the corresponding torque: M θ =kθ+M0 Where, k is the rotational stiffness of the torsion spring, θ is the torsion angle of the torsion spring, and M0 is the preload torque of the torsion spring; The floating clamping wheel drives the floating connecting rod to rotate, generating a torque of: Where F is the minimum clamping force, L is the length of the floating link, is the initial attitude angle of the floating link, is the floating link rotation angle; According to the torque balance and force transmission characteristics of the gear, the torque M θ and torque There is a transmission relationship: in, In a non-circular gear system, the torsion angle θ of the torsion spring and the rotation angle of the floating connecting rod are determined according to the basic principle of gear transmission. The first derivative of the functional relationship between , i is the transmission ratio of the non-circular gear system; We get the differential equation: Solve the differential equation to obtain the transmission ratio function of the non-circular gear system that satisfies constant force clamping:

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