A mixed connection six-pole pot seedling taking and planting integrated mechanism

Abstract

The present application relates to the technical field of agricultural machinery equipment, and more particularly to a hybrid six-link pot seedling taking and transplanting integrated mechanism, comprising: a rack assembly, a crank-rocker mechanism, a first motor unit, a planetary gear train assembly, a second motor unit and a seedling taking arm, the hybrid six-link motion mechanism of the present application comprises a driving part and the seedling taking arm, the driving part is the planetary gear train assembly and a planar four-link mechanism, the planar four-link mechanism comprises a rack, a connecting rod, a rocker and a crank which are sequentially hingedly connected, and the planetary gear train assembly is composed of two-stage conjugate non-circular gears fixed on a housing. The planetary gear train assembly and the planar four-link mechanism are matched, and the angle and position of the seedling taking arm are controlled through non-uniform speed transmission of the non-circular gears in the planetary gear train assembly. Optimization of mechanism parameters and non-circular gear pitch curves enables the seedling taking arm to make high-precision movements that are more in line with requirements, and full-automatic pot seedling taking and transplanting integration is achieved.

Description

Technical Field

[0001] This invention relates to the field of agricultural machinery and equipment technology, and in particular to a hybrid six-stem integrated seedling harvesting and planting mechanism. Background Technology

[0002] The design and research of fully automatic vegetable seedling transplanting machinery is key to solving the problems of large-scale vegetable planting, improving transplanting efficiency, and reducing costs. Currently, the transplanting device of fully automatic vegetable seedling transplanters consists of a seedling-picking component and a seedling-planting component, which suffers from complex mechanical structures, the need for coordination among multiple components to complete the transplanting action, and high costs. Using a single set of mechanical components to complete the transplanting action could simplify the transplanter's structure, improve its reliability, and reduce costs; however, designing an integrated seedling-picking and planting mechanism is currently quite challenging.

[0003] The fully automatic vegetable seedling transplanters researched in Europe and America mainly achieve seedling picking through a combination of mechanics, electricity, and pneumatics. Their structures are relatively complex. The fully automatic transplanter developed by Yanmar Corporation of Japan uses a linkage-slide mechanism to achieve the seedling picking trajectory and works in conjunction with the planting mechanism to complete the transplanting work. The fully automatic vegetable seedling transplanter developed by Zhejiang University of Technology achieves seedling picking and planting through the cooperation of a planetary gear non-circular gear seedling picking mechanism and a planting mechanism. The seedling picking mechanism and the planting mechanism achieve the required movement trajectory for seedling picking and planting through non-circular gear non-uniform speed transmission. The structure is simple, the transplanting efficiency is high, and the working stability is good. However, the seedling picking and planting movement trajectory is relatively simple, which makes the movement of the seedling picking arm relatively inflexible. This results in an unsatisfactory seedling picking effect and makes it difficult to design a transplanting trajectory that meets the requirements of integrated picking and planting. Summary of the Invention

[0004] In view of this, the purpose of this invention is to propose a hybrid six-bar integrated seedling transplanting mechanism to solve the problem that existing fully automatic transplanters cannot achieve integrated transplanting, and to provide a new option for the development of fully automatic vegetable seedling transplanting equipment.

[0005] To achieve the above objectives, the present invention provides a hybrid six-stem potted seedling harvesting and planting integrated mechanism, comprising:

[0006] A rack assembly, the rack assembly including a rack, wherein the first motor unit is fixed on the rack;

[0007] A crank-rocker mechanism includes a connecting rod, on the side of the connecting rod near the frame assembly, a rocker and a crank are rotatably mounted, the other end of the rocker is fixed to a connecting shaft, the other end of the crank is rotatably fixed to the frame via a power shaft, and the connecting shaft is rotatably fixed to the frame.

[0008] The first motor unit includes a first motor, which is coaxially connected to one end of a crank that is rotatably fixed on the frame, and is used to drive the crank to rotate. One end of the crank forms a rotating pair with a connecting rod, and the other end of the connecting rod forms a rotating pair with a rocker arm.

[0009] A planetary gear train assembly includes a housing, on which a planetary shaft, an intermediate shaft, and an input shaft are rotatably mounted. The planetary shaft and the input shaft are located on opposite sides of the intermediate shaft and protrude from the housing. Planetary gears are fixed on the planetary shaft, a sun gear is fixed on the input shaft, and a first intermediate gear and a second intermediate gear are rotatably mounted on the intermediate shaft. The planetary gears, the first intermediate gear, the second intermediate gear, and the sun gear are all located inside the housing.

[0010] The second motor unit includes a second motor, which is fixed on the connecting rod and is used to drive the input shaft to rotate.

[0011] The seedling-taking arm includes a transplanting cam, one end of which is fixed to the housing, and the other end extends into the housing. The end extending into the housing has a notch for actuation. The planetary shaft protrudes from the housing and passes through the transplanting cam to be fixed to the housing. The housing has a spring seat and a lever inside. One end of the seedling-pushing rod is installed in the spring seat, and the other end extends to the outside of the housing and is fixed with a seedling-pushing block. A rotating pin perpendicular to the lever is fixed inside the housing. A lever is rotatably mounted on the rotating pin. One end of the lever is hinged to the spring seat, and the other end extends into the notch for actuation. The seedling needles and the seedling-pushing rod are arranged in parallel, and two sets are symmetrically arranged along the seedling-pushing rod. One end of the seedling needle is hinged to the housing, and the other end passes through the seedling-pushing block.

[0012] The planetary shaft and input shaft are rotatably mounted on the housing, and the intermediate shaft is fixed inside the housing. The first intermediate gear is meshed with the sun gear, and the second intermediate gear is meshed with the planetary gear. The planetary gear, the first intermediate gear, the second intermediate gear, and the sun gear are all non-circular gears. The first intermediate gear and the second intermediate gear are fixedly connected and form a rotating pair with the housing through the intermediate shaft. The planetary shaft forms a rotating pair with the housing. The input shaft protrudes from the housing and is rotatably mounted on the connecting rod.

[0013] Furthermore, the frame assembly also includes a rotating bearing seat and a bearing housing fixed on the frame, the crank is rotatably fixed on the bearing housing, and the connecting shaft is rotatably fixed on the rotating bearing seat.

[0014] Furthermore, two sets of the rotating bearing housing are symmetrically arranged.

[0015] Furthermore, the first motor is fixed to the frame by a mounting plate, and a coupling is fixed on the rotating shaft of the first motor, the coupling being coaxially connected to the power shaft.

[0016] Furthermore, a rotating bearing is fixed on the side of the housing, and the planetary shaft and input shaft are fixed on the rotating bearing and rotatably mounted on the housing via the rotating bearing.

[0017] Furthermore, the second motor unit also includes an L-shaped plate fixed on the connecting rod, the second motor is fixed on the L-shaped plate, the rotation shaft of the second motor is coaxially connected to a driving bevel gear, and the input shaft is coaxially connected to a driven bevel gear, the driving bevel gear and the driven bevel gear are meshed together.

[0018] Furthermore, both the first motor and the second motor are geared motors.

[0019] Furthermore, the outer casing has a notch on the side near the spring seat, and the notch is sealed by a removable top cover.

[0020] The present invention also provides an optimized design method for a hybrid six-stem potted seedling integrated planting and harvesting mechanism. This design method is applicable to the aforementioned hybrid six-stem potted seedling integrated planting and harvesting mechanism. The optimization method includes the following steps:

[0021] S1: Construct a design model for a hybrid six-bar linkage;

[0022] The seedling arm is equivalent to l7, the line connecting the rotation center of the sun gear to the rotation center of the planet gear is equivalent to l6, the line connecting the connecting rod and the rotation center of the sun gear is l5, the assembly relationship between the seedling arm and the shell is equivalent to l7, and l6 is hinged at point E, the assembly relationship between the shell and the connecting rod is equivalent to l6, and l5 is hinged at point D, in the crank-rocker mechanism, crank l1 and frame l4 are hinged at point O, crank l1 and connecting rod l2 are hinged at point A, connecting rod l2 and rocker l3 are hinged at point B, rocker l3 and frame l4 are hinged at point C, and the outer end point G of l7 is equivalent to the tip of the seedling needle.

[0023] Define all angles as counterclockwise as positive. θ is the angle relative to l4 and l5, and τ is the angle relative to l6, expressed as:

[0024]

[0025] In the formula s i (i = 1, 2, 3) are the member steering coefficients, s i When = 1, the corresponding member rotates counterclockwise around the center of rotation. i When θ = -1, the corresponding member rotates clockwise around the center of rotation, where θ in ,τ out The angle between the member and its initial position. θ0 and τ0 are the initial included angles of l1, l6, and l7, where l1 and l6 are input links, l7 is the output link, and the coordinates of the endpoint of link l1 are defined by the expression:

[0026]

[0027] The equation established by the closed loop OABC is:

[0028]

[0029] The horizontal angle ψ of link l2 is obtained as follows:

[0030]

[0031] When AC = 0:

[0032]

[0033] Taking the negative sign of the double solutions in equations (5) and (7), we obtain the coordinates of l6 and l5 hinged at point D as follows:

[0034]

[0035] The pose of point G is calculated from the pose of point D. The coordinates and angles of the tip of the seedling needle, i.e., the outer endpoint G of l7, are:

[0036]

[0037] S2: Construct a functional model of the non-circular gears in the planetary gear train assembly;

[0038] In the non-circular gear mechanism of the planetary gear train assembly, establish the input / output relationship for execution:

[0039]

[0040] Where θ in ,τ out τ represents the rotation angles of the input and output links relative to their initial positions, respectively. mid Given the rotation angle between the first and second intermediate wheels relative to their initial positions, calculate their instantaneous transmission ratio:

[0041]

[0042] The pitch curve function of the first intermediate gear non-circular gear is:

[0043]

[0044] Similarly, the pitch curve function of the second intermediate gear (non-circular gear) is:

[0045]

[0046] An optimization index for evaluating the pitch curve of a non-circular gear is proposed, and its first derivative is:

[0047]

[0048] Then the first-order square integral of the pitch curve function of the non-circular gear of the first intermediate gear is:

[0049]

[0050] Similarly, the square integral of the first derivative of the pitch curve function of the second intermediate gear non-circular gear is:

[0051]

[0052] S3: Parameter optimization design;

[0053] The hybrid six-bar linkage has 12 mechanism parameters: x0, y0, l1, l2, l3, l4, l5, l6, l7, α0, β, γ. The initial included angle between the input and output links is... θ0, τ0, the rotation angle required for the input and output links to reach the next pose is Δθ in(i) ,Δτ mid(i) ,Δτ out(i) , i = 1...N-1;

[0054] Add steering coefficient s i (i = 1, 2, 3), there are a total of 3N + 15 design variables, totaling 57 design variables. The goal is to make the generated trajectory as close as possible to the expected trajectory. The specific parameter optimization is as follows:

[0055] First, the parameters of the NSGA-II algorithm are: genetic population size is set to 100, maximum number of generations is set to 10000, mutation probability is set to 0.2, and crossover probability is set to 0.9.

[0056] Finally, based on the crank's rotation law, which requires satisfying the monotonicity of angular displacement and meeting dynamic requirements, the specific optimized design of the hybrid six-bar linkage is as follows:

[0057] Objective function:

[0058]

[0059] Design variables:

[0060] Upper and lower limits: x0∈[-200,100], y0∈[100,500], l1,l2,l3,l4,l5∈[20,120], l6∈[50,120], l7∈[100,270], α0,β∈[0,2π], initial angle between input and output links. θ0,τ0∈[0,2π], relative angular displacements and their ratios Δθ in(7) ∈[50,120], s1,s2,s3∈{-1,1};

[0061] constraint:

[0062] The dimensional constraints of the mechanism are:

[0063]

[0064] The constraint conditions for synthesizing the pitch curve of a non-circular gear are:

[0065]

[0066] in, and k represents the actual and desired position and angle of the output linkage, respectively. i These are weighting coefficients;

[0067] Using the extinction penalty function method, the objective function increases by a large value for each constraint violation, thus replacing the constrained optimization problem with an unconstrained optimization problem.

[0068]

[0069] Where P1(X,m1) and P2(X,m2) are the penalty functions in the two objective functions, respectively, which can be expressed as: P(X,m)=m·H, where H is the penalty cost value and m is the number of constraints violated;

[0070] After optimizing the mechanism parameters, the next step is to perform secondary optimization on the non-circular gear pitch curve.

[0071] Objective function:

[0072] Design variables: X2 = [Δ(Δτ)] mid1 ...Δ(Δτ) mid(N-1) ),Δ(Δτ out1 ),...Δ(Δτ out(N-1) )];

[0073] Upper and lower limits: Δ(Δτ) mid(i) ),Δ(Δτ out(i) )∈[-10,10],(i=1...13),Δθ out(i) / Δθ mid(i) ∈[0.5,2]; i=1…13;

[0074] Among them, adjusting the parameter p from small to large allows the smoothness and non-circularity of the non-circular curve to reach the optimal level within an acceptable range of angular displacement deviation.

[0075] The beneficial effects of this invention are:

[0076] This invention uses a first motor unit to drive a crank-rocker mechanism, and a second motor unit to drive a seedling-picking arm via a planetary gear train assembly. Simultaneously, the second motor unit also drives the seedling-picking arm to pick up and place seedlings in pots. While placing the seedlings, a seedling-pushing block pushes them forward. The hybrid six-bar linkage includes a drive unit and a seedling-picking arm. The drive unit consists of a planetary gear train assembly and a planar four-bar linkage. The planar four-bar linkage comprises a frame, connecting rods, a rocker arm, and a crank, all sequentially hinged to each other. The tangent equations of the gears within the planetary gear train assembly define the speed ratio between any two gears, thereby improving the accuracy and stability of the seedling-picking arm. The planetary gear train assembly and the planar four-bar linkage work together, and the phase angle of the seedling-picking arm's swing is controlled by the non-circular gears within the planetary gear train assembly, optimizing the trajectory of seedling picking and planting. This allows the seedling-picking arm to perform more complex and accurate movements, making its movement more flexible. By combining the three actions of picking, conveying, and planting, a single mechanism efficiently completes these three actions, achieving fully automated seedling transplanting. Attached Figure Description

[0077] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0078] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0079] Figure 2 This is a schematic diagram of the installation structure of the rack assembly in this invention;

[0080] Figure 3 This is a cross-sectional structural diagram of the planetary gear train assembly in this invention;

[0081] Figure 4 This is a schematic cross-sectional view of the seedling arm in this invention;

[0082] Figure 5 This is a schematic diagram of the structure of the seedling arm in this invention;

[0083] Figure 6 This is a schematic diagram of the transfer cam in this invention;

[0084] Figure 7This is a flowchart illustrating the optimization method in this invention;

[0085] Figure 8 This is a schematic diagram of the hybrid six-bar linkage in this invention;

[0086] Figure 9 This is a schematic diagram of the pose before and after the hybrid optimization in this invention;

[0087] Figure 10 This is a diagram showing the transplanting trajectory of the seedlings in pots before the first optimization of this invention;

[0088] Figure 11 This is a diagram showing the transplanting trajectory of the potted seedlings after the first optimization of this invention;

[0089] Figure 12 This is a comparison diagram of the non-circular gear pitch curves before the second optimization of this invention;

[0090] Figure 13 This is a comparison diagram of the non-circular gear pitch curves after the secondary optimization of the present invention;

[0091] Figure 14 This is a comparison diagram of the final optimized and expected pose of the potted seedling transplanting according to the present invention;

[0092] Figure 15 This is a schematic diagram of the transplanting process of seedlings in pots using the transplanter of this invention.

[0093] Reference numerals: Frame assembly 10, Frame 11, Rotating bearing seat 12, Bearing seat 13, Crank-rocker mechanism 20, Connecting rod 21, Rocker arm 22, Connecting shaft 23, Crank 24, First motor unit 30, First motor 31, Mounting plate 32, Coupling 33, Planetary gear train assembly 40, Housing 41, Planetary shaft 42, Intermediate shaft 43, Input shaft 44, Planetary gear 45, First intermediate gear 46, Second intermediate gear 47, Sun gear 48, Rotating bearing 49, Second motor unit 50, Second motor 51, L-shaped plate 52, Driving bevel gear 53, Driven bevel gear 54, Seedling arm 60, Transplanting cam 61, Housing 62, Top cover 63, Spring seat 64, Seedling pusher 65, Seedling pusher block 66, Seedling needle 67, Pulley 68, Rotating pin 69. Detailed Implementation

[0094] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0095] Example 1

[0096] like Figure 1-6 As shown, the present invention provides a hybrid six-bar integrated seedling picking and planting mechanism, comprising a frame assembly 10, a crank-rocker mechanism 20, a first motor unit 30, a planetary gear system assembly 40, a second motor unit 50, and a seedling picking arm 60, wherein:

[0097] The frame assembly 10 includes a frame 11, the first motor unit 30 is fixed on the frame 11, and the frame assembly 10 also includes a rotating bearing seat 12 and a bearing seat 13 fixed on the frame 11.

[0098] The crank-rocker mechanism 20 includes a connecting rod 21. A rocker arm 22 and a crank 24 are rotatably mounted on the side of the connecting rod 21 near the frame assembly 10. A connecting shaft 23 is fixed to the other end of the rocker arm 22. The other end of the crank 24 is rotatably fixed to the frame 11 via a power shaft. The connecting shaft 23 is rotatably fixed to the frame 11. The crank 24 is rotatably fixed to the bearing seat 13. The connecting shaft 23 is rotatably fixed to the rotating bearing seat 12.

[0099] Furthermore, two sets of the rotating bearing housing 12 are symmetrically arranged.

[0100] Both the rocker arm 22 and the crank 24 can rotate freely around their respective ends. The frame 11, connecting rod 21, rocker arm 22, and crank 24 form a planar four-bar linkage. The first motor unit 30 includes a first motor 31. The first motor 31 and one end of the crank 24, which is rotatably fixed on the frame 11, are coaxially connected to drive the crank 24 to rotate. One end of the crank 24 and the connecting rod 21 form a revolute joint, and the other end of the connecting rod 21 and the rocker arm 22 form a revolute joint.

[0101] Furthermore, the first motor 31 is fixed to the frame 11 by the mounting plate 32, and a coupling 33 is fixed on the rotating shaft of the first motor 31. The coupling 33 is coaxially connected to the power shaft, and the first motor 31 drives the planar four-bar linkage to rotate.

[0102] The planetary gear train assembly 40 includes a housing 41, on which a planetary shaft 42, an intermediate shaft 43, and an input shaft 44 are rotatably mounted. The planetary shaft 42 and the input shaft 44 are located on both sides of the intermediate shaft 43 and protrude from the housing 41. A planetary gear 45 is fixed on the planetary shaft 42, and a sun gear 48 is fixed on the input shaft 44. A first intermediate gear 46 and a second intermediate gear 47 are rotatably mounted on the intermediate shaft 43. The planetary gear 45, the first intermediate gear 46, the second intermediate gear 47, and the sun gear 48 are all located inside the housing 41.

[0103] The planetary shaft 42 and the input shaft 44 are rotatably mounted on the housing 41. The intermediate shaft 43 is fixed inside the housing 41. The first intermediate gear 46 and the sun gear 48 are meshed together. The second intermediate gear 47 and the planetary gear 45 are meshed together. The planetary gear 45, the first intermediate gear 46, the second intermediate gear 47 and the sun gear 48 are all non-circular gears. The first intermediate gear 46 and the second intermediate gear 47 are fixedly connected and form a rotating pair with the housing 41 through the intermediate shaft 43. The planetary shaft 42 forms a rotating pair with the housing 41. The input shaft 44 protrudes from the housing 41 and is rotatably mounted on the connecting rod 21.

[0104] When the input shaft 44 rotates, it drives the sun gear 48 to rotate. The rotation of the sun gear 48 drives the first intermediate gear 46 and the second intermediate gear 47 to rotate, which in turn drives the planet gear 45 and the planetary shaft 42 to rotate. Since the planet gear 45, the first intermediate gear 46, the second intermediate gear 47 and the sun gear 48 are all non-circular gears, the speed ratio between any two gears can be described by the tangent equation, which can more accurately control the transmission ratio. The planetary shaft 42 directly drives the seedling arm 60 to move, which can meet the higher precision and stability requirements of the seedling arm 60.

[0105] Furthermore, a rotating bearing 49 is fixed on the side of the housing 41, and the planetary shaft 42 and the input shaft 44 are fixed on the rotating bearing 49 and rotatably mounted on the housing 41 through the rotating bearing 49.

[0106] The second motor unit 50 includes a second motor 51, which is fixed on the connecting rod 21 and is used to drive the input shaft 44 to rotate. The second motor unit 50 drives the input shaft 44 to rotate.

[0107] Furthermore, the second motor unit 50 also includes an L-shaped plate 52 fixed on the connecting rod 21. The second motor 51 is fixed on the L-shaped plate 52. The rotating shaft of the second motor 51 is coaxially connected to a driving bevel gear 53, and the input shaft 44 is coaxially connected to a driven bevel gear 54. The driving bevel gear 53 and the driven bevel gear 54 are meshed. When the second motor 51 rotates, it drives the driving bevel gear 53 to rotate. Under the meshing of the teeth, the driving bevel gear 53 drives the driven bevel gear 54 to rotate, thereby driving the input shaft 44 to rotate.

[0108] Optionally, both the first motor 31 and the second motor 51 are geared motors. The geared motors reduce the speed of the motor through a reducer and increase the torque output. The stable output torque can better support the relatively heavy potted seedlings and ensure the stability of the seedling picking and planting process.

[0109] The seedling arm 60 includes a transplanting cam 61. One end of the transplanting cam 61 is fixed to the housing 41, and the other end extends into the interior of the outer shell 62. The end extending into the interior of the outer shell 62 is provided with a turning notch. The planetary shaft 42 protrudes from the housing 41 and passes through the transplanting cam 61 and is fixed to the outer shell 62. When the planetary shaft 42 rotates, the housing 41 rotates under the drive of the planetary shaft 42, but the transplanting cam 61 does not rotate with the rotation of the planetary shaft 42.

[0110] The outer casing 62 contains a spring seat 64 and a lever 68. One end of the seedling pusher 65 is installed inside the spring seat 64, and the other end extends to the outside of the outer casing 62 and is fixed with a seedling pusher block 66. A rotating pin 69 perpendicular to the lever 68 is fixed inside the outer casing 62. The lever 68 is rotatably mounted on the rotating pin 69. One end of the lever 68 is hinged to the spring seat 64, and the other end extends into the actuation notch. The seedling needles 67 and the seedling pusher 65 are arranged in parallel, and two sets are symmetrically arranged along the seedling pusher 65. One end of the seedling needle 67 is hinged to the outer casing 62, and the other end passes through the seedling pusher block 66. The non-hinged ends of the two seedling needles 67 are open, and the seedling pusher 65 can drive the seedling pusher block 66 to move. When the seedling pusher block 66 moves, its position relative to the seedling needle 67 changes.

[0111] When the entire seedling arm 60 rotates, the actuation notch is a semi-circular notch. The housing 41 rotates, and the lever 68 rotates accordingly. The actuation notch pushes one end of the lever 68, and the lever 68 rotates relative to the rotating pin 69, which pushes the spring seat 64 and the seedling pusher 65 to move back and forth. When the seedling pusher 65 moves back and forth, it drives the seedling pusher block 66 to move back and forth, so that the two seedling needles 67 continuously open and close, completing the picking and placing of the seedlings in the pot.

[0112] Furthermore, the outer casing 62 has a notch on the side near the spring seat 64, and the notch is sealed by a removable top cover 63.

[0113] like Figure 7-15 As shown, the present invention also provides an optimized design method for a hybrid six-stem potted seedling integrated planting and harvesting mechanism. This design method is applicable to the aforementioned hybrid six-stem potted seedling integrated planting and harvesting mechanism. The optimization method includes the following steps:

[0114] S1: Construct a design model for a hybrid six-bar linkage;

[0115] like Figure 8The schematic diagram of the hybrid six-bar linkage model shows that the seedling arm 60 is equivalent to l7, the line connecting the rotation center of the sun gear 48 to the rotation center of the planet gear 45 is equivalent to l6, the line connecting the rotation center of the connecting rod 21 and the rotation center of the sun gear 48 is l5, the assembly relationship between the seedling arm 60 and the housing 41 is equivalent to l7, and l6 is hinged at point E. The assembly relationship between the housing 41 and the connecting rod 21 is equivalent to l6, and l5 is hinged at point D. In the crank-rocker mechanism 20, the crank 24l1 and the frame 11l4 are hinged at point O, the crank 24l1 and the connecting rod 21l2 are hinged at point A, the connecting rod 21l2 and the rocker 22l3 are hinged at point B, the rocker 22l3 and the frame 11l4 are hinged at point C, and the outer end point G of l7 is equivalent to the tip of the seedling needle 67.

[0116] The 14 positions for the seedling picking and planting process of mechanized transplanting of seedlings in pots: the first 7 positions are used to pick up the seedlings from the pot, and the last 7 positions are used to plant the seedlings. Among them, the 1st, 7th, 8th and 14th positions have lower precision requirements. The horizontal angle of the two seedling needles 67 of the seedling picking arm 60 as the gripping device needs to be kept stable during the seedling picking and planting process.

[0117] The mechanism does not collide with the pot wall or the ground during movement, and ensures that the seedlings do not flip over, thus avoiding damage. The 14 pose data and weight coefficients are shown in Table (1) below:

[0118] Table (4) Required pose data and weighting coefficients for the gripping device

[0119]

[0120]

[0121] The non-circular gear-constrained hybrid six-bar linkage within the planetary gear train assembly 40 can be divided into two parts: the first is the bottom four-bar linkage, and the second is the RR chain using non-circular gear coupling. The two parts are connected in series, and the entire hybrid mechanism is driven by two input rods with the same rotational speed.

[0122] Define all angles as counterclockwise as positive. θ is the angle relative to l4 and l5, and τ is the angle relative to l6, expressed as:

[0123]

[0124] In the formula s i (i = 1, 2, 3) are the member steering coefficients, s i When = 1, the corresponding rod rotates counterclockwise around the center of rotation, s i When θ = -1, the corresponding member rotates clockwise around the center of rotation, where θ in ,τ out The angle between the member and its initial position. θ0 and τ0 are the initial included angles of l1, l6, and l7, where l1 and l6 are input links, l7 is the output link, and the coordinates of the endpoint of link l1 are defined by the expression:

[0125]

[0126] The equation established by the closed loop OABC is:

[0127]

[0128] The horizontal angle ψ of link l2 is obtained as follows:

[0129]

[0130] When AC = 0:

[0131]

[0132] The double solutions in equations (5) and (7) are due to the fact that the two parts of the mechanism can be combined in different configurations. In this embodiment, only the case of taking the negative sign is considered, and the coordinates of l6 and l5 hinged at point D are obtained as follows:

[0133]

[0134] The pose of point G is calculated from the pose of point D. The coordinates and angles of the tip of the seedling needle 67, i.e., the outer endpoint G of l7, are:

[0135]

[0136] S2: Construct a functional model of the non-circular gears in the planetary gear train assembly 40;

[0137] In the non-circular gear mechanism of planetary gear train assembly 40, the input / output relationship for execution is established:

[0138]

[0139] Where θ in ,τ out τ represents the rotation angles of the input axis and the planetary axis relative to their initial positions, respectively. mid Given the rotation angle between the input link and the output link relative to their initial positions, calculate their instantaneous transmission ratio:

[0140]

[0141] The pitch curve function of the first intermediate gear 46 non-circular gear is:

[0142]

[0143] Similarly, the pitch curve function of the second intermediate gear 47 (non-circular gear) is:

[0144]

[0145] To reduce the non-circularity and improve the smoothness of the non-circular gear pitch curve, an optimization index for evaluating the non-circular gear pitch curve is proposed, which is the integral of the square of the first derivative of the non-circular gear pitch curve function. The first derivative is:

[0146]

[0147] Then the first-order square integral of the pitch curve function of the first intermediate gear 46 non-circular gear is:

[0148]

[0149] Similarly, the first-order square integral of the pitch curve function of the second intermediate gear 47 non-circular gear is:

[0150]

[0151] S3: Parameter optimization design;

[0152] The hybrid six-bar linkage has 12 mechanism parameters: x0, y0, l1, l2, l3, l4, l5, l6, l7, α0, β, γ. The initial included angle between the input and output links is... θ0, τ0, the rotation angle required for the input and output links to reach the next pose is Δθ in(i) ,Δτ mid(i) ,Δτ out(i) i = 1...N-1; plus the steering coefficient s i (i = 1, 2, 3), there are a total of 3N + 15 design variables, totaling 57 design variables. The goal is to make the generated trajectory as close as possible to the expected trajectory. The specific parameter optimization is as follows:

[0153] First, the parameters of the NSGA-II algorithm are: genetic population size is set to 100, maximum number of generations is set to 10000, mutation probability is set to 0.2, and crossover probability is set to 0.9.

[0154] Finally, based on the rotation law of crank 24, which requires satisfying the requirement of monotonicity of angular displacement and dynamic requirements, the specific optimized design of the hybrid six-bar linkage is as follows:

[0155] Objective function:

[0156]

[0157] Design variables:

[0158] Upper and lower limits: x0∈[-200,100], y0∈[100,500], l1,l2,l3,l4,l5∈[20,120], l6∈[50,120], l7∈[100,270], α0,β∈[0,2π], initial angle between input and output links. θ0,τ0∈[0,2π], relative angular displacements and their ratios Δθ in(7) ∈[50,120],s1,s2,s3∈{-1,1}

[0159] constraint:

[0160] The dimensional constraints of the mechanism are:

[0161]

[0162] The constraint conditions for synthesizing the pitch curve of a non-circular gear are:

[0163]

[0164] in, and k represents the actual and desired position and angle of the output linkage, respectively. i These are weighting coefficients;

[0165] Using the extinction penalty function method, the objective function increases by a large value for each constraint violation, thus replacing the constrained optimization problem with an unconstrained optimization problem.

[0166]

[0167] Where P1(X,m1) and P2(X,m2) are the penalty functions in the two objective functions, respectively, which can be expressed as: P(X,m)=m·H, where H is the penalty cost value and m is the number of constraints violated. The optimization results of the algorithm are shown in Table (2) and Table (3) below:

[0168] Table (2) Optimization Results

[0169]

[0170] Table (3) Optimization Results

[0171]

[0172]

[0173] The optimized parameters can be used to derive a simplified diagram of the overall mechanism and the transplanting trajectory. Figure 9A simplified diagram of the hybrid six-bar linkage corresponding to the mechanism parameters is given, along with the desired pose and the pose before joint curve optimization. It can be seen from the figure that the mechanism is relatively concentrated, with short dimensions and a relatively simple structure.

[0174] During the mechanism's movement, the clamping device does not collide with the pot wall when picking up seedlings, but it does collide with the ground when planting seedlings. Apart from this, other links in the mechanism do not collide with the ground, and there is no interference between the links. The overall pose deviates little from the required pose, meeting the design requirements. However, its pose accuracy can be further improved, so the next step is to optimize the non-circular gear pitch curve.

[0175] After optimizing the mechanism parameters and determining a good initial solution, the next step is to perform secondary optimization on the non-circular gear pitch curve, while ensuring that the key pose deviations are not too large.

[0176] Objective function:

[0177] Design variables: X2 = [Δ(Δτ)] mid1 ...Δ(Δτ) mid(N-1) ),Δ(Δτ out1 ),...Δ(Δτ out(N-1) )];

[0178] Upper and lower limits: Δ(Δτ) mid(i) ),Δ(Δτ out(i) )∈[-10,10],(i=1...13),Δθ out(i) / Δθ mid(i) ∈[0.5,2]; i=1…13;

[0179] The parameter p is adjusted from small to large to achieve optimal smoothness and non-circularity of the non-circular curve within an acceptable range of angular displacement deviation. Calculations show that when p = 0.95, the smoothness and non-circularity of the non-circular curve reach their optimal levels.

[0180] In this embodiment, the maximum value point of the horizontal coordinate on the target transplanting trajectory curve is the seedling collection point, the minimum value point of the vertical coordinate is the seedling planting point, and the seedling collection start point is the inner endpoint of the loop.

[0181] Before and after optimization, the angular displacement function curve and the transmission ratio curve of the circular gear are smoother and more fluid than before optimization. The change in the total angular displacement function curve is concentrated in the part corresponding to the constrained pose, while the curve part corresponding to the key pose changes less. The overall changes in the function curves f and g are small before and after optimization, but the fluctuation of the transmission ratio curve decreases significantly, resulting in a smoother transmission. Figure 10 and Figure 11 The optimization effect of the non-circular gear pitch curves before and after optimization is intuitively shown.

[0182] Local optimization of the node curve reduces local unevenness in the non-circular gear pitch curve, making it smoother. Comparative results verify that the optimization index for the non-circular gear pitch curve proposed in this invention not only ensures that the centroid of the non-circular gear does not deviate excessively from the center of rotation but also guarantees the smoothness of the non-circular gear pitch curve. Figure 12 and Figure 13 The image shows a comparison between the final optimized and expected poses of the seedling transplanting mechanism. The corresponding trajectory is the actual transplanting trajectory of the hybrid six-bar integrated seedling picking and planting mechanism implemented in this invention. It can be seen that the transplanting trajectory after the second optimization of the non-circular gear pitch curve is significantly improved compared to the first optimization. The pose deviation of the gripping device is smaller, and the error compared to the expected pose is also smaller. Simultaneously, the seedling picking trajectory and the seedling planting trajectory have been significantly improved, which helps to increase the success rate of seedling picking and reduce damage to the seedlings caused by the gripping device during planting. The width of the ring in the transplanting trajectory is less than 2 mm; therefore, the actual transplanting trajectory can effectively realize the integrated seedling picking and planting function.

[0183] The final algorithm optimization results obtained through secondary optimization are shown in Table (4):

[0184] Table (4) Final Algorithm Optimization Results

[0185]

[0186] To achieve integrated seedling transplanting and potting, and to make the fully automatic seedling transplanter simple, compact, reliable, and low-cost, this embodiment provides an optimized design method for a hybrid six-bar integrated seedling transplanting and potting mechanism. Based on the initial trajectory of the hybrid six-bar integrated seedling transplanting and potting mechanism, kinematic analysis and non-circular gear pitch curve analysis are performed. With the goal of minimizing the error between the actual and required pose of the hybrid mechanism, the parameters of the hybrid six-bar integrated seedling transplanting and potting mechanism are optimized using the NSGA-II algorithm, obtaining the design variable calculation results. The increment of the input angle change is used as the design variable. With the goal of minimizing the fluctuation of the increment, the non-circular gear pitch curve is optimized using the Variable Neighborhood Search (VNS) algorithm, obtaining the design variable calculation results.

[0187] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0188] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A mixed connection six-pole pot seedling taking and planting integrated mechanism, characterized in that, The utility model relates to a seedling taking device, which comprises a rack assembly (10) including a rack (11), a first motor unit (30) fixed on the rack (11); a crank rocker mechanism (20) including a connecting rod (21), a rocker (22) and a crank (24) rotatably installed on one side of the rack assembly (10) close to the rack assembly (10), the other end of the rocker (22) being fixed with a connecting shaft (23), the other end of the crank (24) being rotatably fixed on the rack (11) through a power shaft, the connecting shaft (23) being rotatably fixed on the rack (11); the first motor unit (30) including a first motor (31), the first motor (31) being coaxially connected with one end of the crank (24) rotatably fixed on the rack (11) and used for driving the crank (24) to rotate, one end of the crank (24) constituting a rotary pair with the connecting rod (21), the other end of the connecting rod (21) constituting a rotary pair with the rocker (22); a planetary gear train assembly (40) including a housing (41), the housing (41) being rotatably provided with a planetary shaft (42), an intermediate shaft (43) and an input shaft (44), the planetary shaft (42) and the input shaft (44) being located on the two sides of the intermediate shaft (43) and protruding from the housing (41), the planetary shaft (42) being fixed with a planetary gear (45), the input shaft (44) being fixed with a sun gear (48), the intermediate shaft (43) being rotatably provided with a first intermediate gear (46) and a second intermediate gear (47), the planetary gear (45), the first intermediate gear (46), the second intermediate gear (47) and the sun gear (48) all being located inside the housing (41); a second motor unit (50) including a second motor (51), the second motor (51) being fixed on the connecting rod (21) and used for driving the input shaft (44) to rotate; a seedling taking arm (60) including a transplanting cam (61), one end of the transplanting cam (61) being fixed on the housing (41), the other end extending into a housing (62), the other end being provided with a pushing gap, the planetary shaft (42) protruding from the housing (41) and being fixed on the housing (62) through the transplanting cam (61), the housing (62) being provided with a spring seat (64) and a pushing rod (68), one end of a seedling pushing rod (65) being installed in the spring seat (64), the other end extending out of the housing (62) and being fixed with a seedling pushing block (66), the housing (62) being fixed with a rotary pin (69) perpendicular to the pushing rod (68), the rotary pin (69) being rotatably provided with the pushing rod (68), one end of the pushing rod (68) being hinged on the spring seat (64), the other end extending into the pushing gap, the seedling needles (67) and the seedling pushing rod (65) being parallelly arranged and symmetrically arranged in two groups along the seedling pushing rod (65), one end of the seedling needles (67) being hinged on the housing (62), the other end penetrating through the seedling pushing block (66). ​ ​ ​ ​ ​ ​ The planetary shaft (42) and the input shaft (44) are rotatably mounted on the housing (41), the intermediate shaft (43) is fixed inside the housing (41), the first intermediate wheel (46) and the sun wheel (48) are in meshing connection, the second intermediate wheel (47) and the planetary wheel (45) are in meshing connection, the planetary wheel (45), the first intermediate wheel (46), the second intermediate wheel (47) and the sun wheel (48) are all non-circular gear, the first intermediate wheel (46) is fixedly connected with the second intermediate wheel (47) and forms a rotary pair with the housing (41) through the intermediate shaft (43), the planetary shaft (42) forms a rotary pair with the housing (41), and the input shaft (44) is rotatably mounted on the connecting rod (21) after protruding out of the housing (41).

2. The hybrid six-pole pot seedling taking and transplanting integrated mechanism according to claim 1, characterized in that: The rack assembly (10) further comprises a rotary bearing seat (12) and a bearing seat (13) fixed on the rack (11), the crank (24) is rotatably fixed on the bearing seat (13), and the connecting shaft (23) is rotatably fixed on the rotary bearing seat (12).

3. The hybrid six-pole pot seedling taking and transplanting integrated mechanism according to claim 2, characterized in that: The rotary bearing seat (12) is symmetrically provided with two groups.

4. The hybrid six-pole pot seedling taking and transplanting integrated mechanism according to claim 1, characterized in that: The first motor (31) is fixed on the rack (11) through the mounting plate (32), the rotary shaft of the first motor (31) is fixed with the shaft coupling (33), and the shaft coupling (33) is coaxially connected with the power shaft.

5. The hybrid six-pole pot seedling taking and transplanting integrated mechanism according to claim 1, characterized in that: The housing (41) is fixed with a rotary bearing (49) on the side surface, the planetary shaft (42) and the input shaft (44) are fixed on the rotary bearing (49) and rotatably mounted on the housing (41) through the rotary bearing (49).

6. The hybrid six-pole pot seedling taking and transplanting integrated mechanism according to claim 1, characterized in that: The second motor unit (50) further comprises an L-shaped plate (52) fixed on the connecting rod (21), the second motor (51) is fixed on the L-shaped plate (52), the rotary shaft of the second motor (51) is coaxially connected with the driving bevel gear (53), the input shaft (44) is coaxially connected with the driven bevel gear (54), and the driving bevel gear (53) and the driven bevel gear (54) are in meshing connection.

7. The hybrid six-pole pot seedling taking and planting integrated mechanism according to claim 1, characterized in that: The first motor (31) and the second motor (51) are both speed reduction motors. 8.The hybrid six-link pot seedling taking and transplanting integrated mechanism according to claim 1, characterized in that: The side surface of the shell (62) close to the spring seat (64) is provided with a notch, and the notch is blocked by a detachable top cover (63).

Images