Design method and system of transplanting seedling mechanism with secondary special-shaped non-circular gear transmission

Abstract

The present invention discloses a design method and system for a secondary special-shaped non-circular gear transmission transplanting and seedling picking mechanism, wherein the method comprises: obtaining key points of transplanting and seedling picking operation; interpolating based on the key points to obtain an ideal planting trajectory; based on the ideal planting trajectory, calculating the length and posture of two rods in a preset two-rod mechanism model, and calculating the total transmission ratio in the seedling picking process, wherein the posture is calculated using an iterative method based on a posture matrix; based on a planetary gear train formed by two groups of gears, allocating a two-stage transmission ratio to obtain a secondary special-shaped non-circular gear transmission transplanting and seedling picking mechanism. The design method and system for the secondary special-shaped non-circular gear transmission transplanting and seedling picking mechanism of the present invention constructs a relatively simple posture matrix through an approximate algorithm, and can more conveniently calculate the posture of the two rods in the two-rod model through an iterative method, with high calculation efficiency, and the obtained transplanting trajectory is closer to the requirements of the ideal trajectory, while the planetary gear train has stable transmission, and the accuracy and reliability of the seedling picking mechanism are high.

Description

Technical Field

[0001] The invention relates to the technical field of agricultural machinery design, and in particular to a design method and system for a secondary special-shaped non-circular gear transmission transplanting seedling picking mechanism. Background Art

[0002] The secondary special-shaped non-circular gear transmission mechanism is the main transmission mechanism of the transplanting seedling picking mechanism of the rice transplanter. Since the seedling picking needle of the transplanting seedling picking mechanism needs to pass through specific points and be buckled as required to bypass the transplanted seedlings after planting, the motion accuracy of the secondary special-shaped non-circular gear transmission mechanism is required to be high.

[0003] At present, the design of non-circular gear planetary gear trains mostly adopts the method of constructing the connection between the gear train size and the generated seedling removal trajectory, and positively adjusting to adapt to the ideal trajectory. The design process is long and the degree of fitting of the target trajectory is low. The reverse solution generally uses regular-shaped gears, such as elliptical gears and eccentric gears, and other gears with parameterized gear pitch curves. The design has great limitations, and there is a certain deviation between the design results and the ideal trajectory.

[0004] In the prior art, patent CN103939531A uses Fourier function segmented transmission ratio to design a non-circular gear planetary system, and its method is complex and has low calculation efficiency; patents CN109826927A and CN105009754A both design and calculate the non-circular gear transmission mechanism through key points, including the following steps: obtain an ideal trajectory according to the key points, construct a two-bar mechanism according to the ideal trajectory and calculate the length and posture of the two bars, calculate the total transmission ratio and distribute the transmission ratio. In the above two prior arts, both disclose a method for calculating the length of the two-bar mechanism, but the solution calculation of the posture of the two-bar mechanism is complex, and the posture of the two bars needs to be calculated through complex relationship matrices and constraints, and the calculation steps are complex and inefficient. Summary of the invention

[0005] Purpose of the invention: In order to overcome the deficiencies in the prior art, the present invention provides a design method and system for a secondary special-shaped non-circular gear transmission transplanting and seedling taking mechanism, aiming to solve the problem of complex posture calculation of a two-rod model.

[0006] Technical solution: To achieve the above purpose, the design method of the secondary special-shaped non-circular gear transmission transplanting seedling mechanism of the present invention includes:

[0007] Get the key points of transplanting and seedling taking operations;

[0008] Interpolation is performed based on the key points to obtain an ideal planting trajectory;

[0009] Based on the ideal planting trajectory, the lengths and postures of the two rods in the preset two-rod mechanism model are calculated, and the total transmission ratio in the seedling removal process is calculated;

[0010] Based on the planetary gear train formed by two sets of gears, two-stage transmission ratio is allocated to obtain a secondary special-shaped non-circular gear transmission transplanting and seedling taking mechanism;

[0011] The step of calculating the lengths and postures of two rods in a preset two-rod mechanism model based on the ideal planting trajectory, and calculating the total transmission ratio in the seedling removal process includes:

[0012] Get the key points of transplanting and seedling taking operations;

[0013] Interpolation is performed based on the key points to obtain an ideal planting trajectory;

[0014] Based on the ideal planting trajectory, the lengths and postures of the two rods in the preset two-rod mechanism model are calculated, and the total transmission ratio in the seedling removal process is calculated;

[0015] Based on the planetary gear train formed by two sets of gears, two-stage transmission ratio is allocated to obtain a secondary special-shaped non-circular gear transmission transplanting and seedling taking mechanism;

[0016] The step of calculating the lengths and postures of two rods in a preset two-rod mechanism model based on the ideal planting trajectory, and calculating the total transmission ratio in the seedling removal process includes:

[0017] According to the formula Calculate the lengths of the two rods in the two-rod mechanism model, where l1 and l2 are the lengths of the two rods respectively; d max is the distance between the point farthest from the rotation center in the ideal planting trajectory and the rotation center; d min is the distance between the point closest to the rotation center in the ideal planting trajectory and the rotation center;

[0018] Calculate the posture parameters δ and θ of the two-bar mechanism model by using an iterative method according to the posture matrix, where δ and θ are two parameters representing the posture of the two-bar mechanism model;

[0019] Calculate the total transmission ratio i 13 =dδ / dθ;

[0020] The posture matrix is: in: f1(δ,θ) and f2(δ,θ) are the deviation functions of the end points on the horizontal and vertical axes respectively; x i With y i are the horizontal and vertical coordinates of the end points respectively; f1′(δ) and f1′(θ) are the partial derivatives of f1(δ,θ) with respect to the variables δ and θ respectively; f2′(δ) and f2′(θ) are the partial derivatives of f2(δ,θ) with respect to the variables δ and θ respectively.

[0021] Furthermore, the planetary gear train formed by the two sets of gears allocates two-stage transmission ratios to obtain a secondary special-shaped non-circular gear transmission transplanting and seedling taking mechanism, which includes:

[0022] The optimal solution is obtained by optimizing the calculation according to the transmission ratio distribution formula and the restriction conditions, and the relationship between the intermediate wheel rotation angle β and the sun wheel rotation angle δ is obtained; wherein: the transmission ratio distribution formula is The restriction is i 12 (δ) is the transmission ratio between the sun gear and the intermediate gear; k(δ) is a continuous piecewise function related to the sun gear rotation angle δ, and k(δ) is the optimized variable; i 13 (δ) is the total transmission ratio of the planetary gear train; β(δ) is the function of the intermediate gear rotation angle with respect to the sun gear rotation angle δ;

[0023] according to Solve to get the radial direction of the sun gear at angle δ; where l3 is the center distance between adjacent gears;

[0024] According to r 21 (β) = l3-r1(δ) Solve to get the radial direction of the intermediate wheel meshing with the sun gear;

[0025] according to Solve to get the radial direction of the planetary gear at angle θ; where i 23 is the transmission ratio between the intermediate gear and the planetary gear, and i 23 =i 13 / i 12 ;

[0026] According to r 23 (β)=l3-r3(θ) is solved to obtain the radial direction of the intermediate wheel meshing with the planetary gear.

[0027] Furthermore, the interpolation based on the key points to obtain an ideal planting trajectory includes:

[0028] Calculate all chord lengths d(i) according to the coordinates of the key points, and use a parameterized formula to calculate the ratio of the first i segments of chord length to the total chord length to obtain a parameterized value; wherein: the chord length d(i) is the distance between the i-th key point and the i+1-th key point, i=1,2…a, a is the total number of key points;

[0029] Inversely calculate the coordinates of the control points of the cubic B-spline curve according to the coordinates of the key points, the B-spline basis recursive algorithm and the parameterized value;

[0030] The ideal planting trajectory is obtained according to the coordinates of the control points.

[0031] Furthermore, the parameterized formula is:

[0032]

[0033] Where: u(i) is the ratio of the sum of the lengths of the first i chords to the total length of all chords;

[0034] represents the length of the jth chord;

[0035] x(j) and y(j) are the horizontal and vertical coordinates of the jth key point respectively.

[0036] Furthermore, the B-spline basis recursive algorithm is:

[0037] Among them, N i,k (t) is the k-th B-spline basis function of the i-th segment, and u i is a node that belongs to the real number sequence U, and u i ≤u i+1 ; t is the recursive algorithm variable;

[0038] The coordinates of the control points of the cubic B-spline curve are inversely calculated based on the coordinates of the key points, the B-spline basis recursive algorithm and the parameterized value as follows:

[0039] According to the formula [x k (i)y k (i)]=A - *[x(i)y(i)} calculates the coordinates of the control point;

[0040] Where: x k (i) and y k (i) are the horizontal and vertical coordinates of the i-th control point;

[0041] A - is the inverse matrix of the inverse matrix A(i,j);

[0042] Inverse Matrix

[0043] Furthermore, obtaining the ideal planting trajectory according to the coordinates of the control points includes:

[0044] According to the formula Calculate the coordinates of the jth end point in the i-th track segment, where: X(i,j) and Y(i,j) are the horizontal and vertical coordinates of the jth end point in the i-th track segment, respectively. is the variable of the end point recursive algorithm, and m is the number of parts into which the i-th trajectory is divided;

[0045] Generate the i-th trajectory according to the coordinates of all the end points;

[0046] The ideal planting trajectory is obtained according to all the trajectories.

[0047] The design system of the secondary special-shaped non-circular gear transmission transplanting seedling mechanism includes:

[0048] An acquisition module is used to acquire key points of transplanting and seedling taking operations;

[0049] A trajectory generation module, which is used to interpolate based on the key points to obtain an ideal planting trajectory;

[0050] A first calculation module, which is used to calculate the length and posture of two rods in a preset two-rod mechanism model based on the ideal planting trajectory, and calculate the total transmission ratio in the seedling removal process;

[0051] The second calculation module is used to allocate two-stage transmission ratios based on the planetary gear train formed by two sets of gears to obtain a secondary special-shaped non-circular gear transmission transplanting and seedling taking mechanism;

[0052] The first calculation module includes:

[0053] Rod length calculation module, according to the formula Calculate the lengths of the two rods in the two-rod mechanism model, where l1 and l2 are the lengths of the two rods respectively; d max is the distance between the point farthest from the rotation center in the ideal planting trajectory and the rotation center; d min is the distance between the point closest to the rotation center in the ideal planting trajectory and the rotation center;

[0054] The posture calculation module calculates the posture parameters δ and θ of the two-bar mechanism model by using an iterative method according to the posture matrix, where δ and θ are two parameters representing the posture of the two-bar mechanism model;

[0055] Transmission ratio calculation module, calculates the total transmission ratio i 13 =dδ / dθ;

[0056] The posture matrix is: in: f1(δ,θ) and f2(δ,θ) are the deviation functions of the end points on the horizontal and vertical axes respectively; i With y i are the horizontal and vertical coordinates of the end points respectively; f1′(δ) and f1′(θ) are the partial derivatives of f1(δ,θ) with respect to the variables δ and θ respectively; f′2(δ) and f′2(θ) are the partial derivatives of f2(δ,θ) with respect to the variables δ and θ respectively.

[0057] Beneficial effects: The design method and system of the secondary special-shaped non-circular gear transmission transplanting seedling picking mechanism of the present invention constructs a relatively simple posture matrix through an approximate algorithm, and can conveniently calculate the postures of the two rods in the two-rod model through an iterative method. The calculation efficiency is high, and the obtained transplanting trajectory is closer to the requirements of the ideal trajectory. At the same time, the planetary gear system has a stable transmission, and the accuracy and reliability of the seedling picking mechanism are high. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 It is a flow chart of the design method of the transplanting and seedling taking mechanism with secondary special-shaped non-circular gear transmission;

[0059] Figure 2 This is a schematic diagram of the locations of 12 key points in the seedling collection trajectory;

[0060] Figure 3 is a schematic diagram of a two-bar mechanism model;

[0061] Figure 4 A schematic diagram of a planetary gear train formed by two sets of gears;

[0062] Figure 5 It is a collection diagram of all key points and control points;

[0063] Figure 6 To obtain the ideal planting trajectory diagram;

[0064] Figure 7 It is a schematic diagram of the design system of the transplanting and seedling taking mechanism with secondary special-shaped non-circular gear transmission;

[0065] Figure 8 Design a visual interface for the system;

[0066] Fig. 9 Display interface of static trajectory obtained for a calculation example;

[0067] Fig.10 The dynamic trajectory display interface obtained for a calculation example. DETAILED DESCRIPTION

[0068] The following embodiments are described by taking transplanting large rice seedlings as an example.

[0069] like Figure 1 The design method of the secondary special-shaped non-circular gear transmission transplanting seedling picking mechanism shown includes the following steps S101-S104:

[0070] Step S101, obtaining key points of transplanting seedlings;

[0071] In this embodiment, Figure 2As shown in the figure, according to the physical characteristics of large rice seedlings and the agronomic requirements of planting, the positions of 12 key points in the seedling removal trajectory are determined, and according to the importance of the key points, the 12 key points are divided into 6 positioning key points and 6 fine-tuning key points. At the fine-tuning key point a, the posture of the seedling needle before entering the seedling tray is changed; at the positioning key point A, the seedling needle enters the seedling tray and starts the seedling removal and clamping operation; at the positioning key point B, the seedling needle clamps the seedling and detaches from the seedling gate; the fine-tuning key point b is the seedling holding stage point, which maintains the seedling delivery posture; at the fine-tuning key point c, the posture of the seedling before entering the soil is changed; the positioning key point C is the soil entry point, and the seedling needle holds the seedling and plants it in the soil; the positioning key point D is the unearthing point, the seedling needle ends pushing the seedling and enters the return stage; the fine-tuning key point d controls the return direction, and cooperates with the fine-tuning key points e and f to achieve rapid return and increase the height around the seedling; the positioning key points E and F determine the overall height of the trajectory. The above key points are from Figure 2 Starting from point a in the middle, they are numbered 1, 2, 3...12 in clockwise order.

[0072] Step S102, interpolating based on the key points to obtain an ideal planting trajectory;

[0073] In this embodiment, a cubic B-spline curve is used for interpolation to obtain the ideal planting trajectory. During the interpolation process, the values ​​of the positioning key points are kept unchanged. In order to maintain the smooth continuity of the obtained ideal planting trajectory, the values ​​of the fine-tuning key points can be modified within a preset range.

[0074] Step S103, based on the ideal planting trajectory, calculating the length and posture of two rods in the preset two-rod mechanism model, and calculating the total transmission ratio in the seedling removal process;

[0075] In this step, the two-bar mechanism model is as follows Figure 3 As shown, the lengths of the OX and XY rods are l1 and l2 respectively, and the postures of the two rods are represented by the arm rotation angle δ and the planetary gear rotation angle θ.

[0076] Step S104, based on the planetary gear train formed by the two sets of gears, two-stage transmission ratio is allocated to obtain a secondary special-shaped non-circular gear transmission transplanting and seedling taking mechanism.

[0077] In this step, if Figure 4As shown, the planetary gear train formed by two sets of gears includes a sun gear 01, an intermediate gear 02 and a planetary gear 03. In this embodiment, both sides of the sun gear 01 have intermediate gears 02 and planetary gears 03, and the number of intermediate gears 02 on each side is two, and the two intermediate gears 02 are coaxially arranged, and the two are respectively meshed with the sun gear 01 and the planetary gear 03 on the same side. In addition to the two-stage transmission ratio, the parameters of the secondary special-shaped non-circular gear transmission transplanting and seedling taking mechanism are determined, including the radial direction corresponding to the sun gear 01 at an angle of δ (when δ is an arbitrary angle value), the radial direction of the intermediate gear 02 meshing with the sun gear, the radial direction corresponding to the planetary gear 03 at an angle of θ, and the radial direction of the intermediate gear 02 meshing with the planetary gear 03.

[0078] The interpolation based on the key points in the above step S102 to obtain the ideal planting trajectory includes the following steps S201-S203:

[0079] Step S201, calculating all chord lengths d(i) according to the coordinates of the key points, and using a parameterized formula to calculate the ratio of the first i chord lengths to the total chord lengths, to obtain a parameterized value; wherein: the chord length d(i) is the distance between the i-th key point and the i+1-th key point, i=1,2…a, a is the total number of the key points;

[0080] In this step, specifically, the parameterization formula is:

[0081] Where: u(i) is the ratio of the sum of the lengths of the first i chords to the total length of all chords;

[0082] represents the length of the jth chord, that is, the distance between the jth key point and the j+1th key point; x(j) and y(j) are the horizontal and vertical coordinates of the jth key point respectively.

[0083] Step S202, inversely calculating the coordinates of the control points of the cubic B-spline curve according to the coordinates of the key points, the B-spline basis recursive algorithm and the parameterized value; Figure 5 It is a collection diagram of all key points and control points.

[0084] Step S203, obtaining the ideal planting trajectory according to the coordinates of the control points. Figure 6 This is the ideal planting trajectory map obtained based on the control points.

[0085] The B-spline basis recursive algorithm in step S202 is:

[0086] Among them, N i,k (t) is the k-th B-spline basis function of the i-th segment, and u i 、ui+1 is a node, which belongs to the preset real number sequence U, and u i ≤u i+1 , that is, U is a non-decreasing sequence; t is a recursive algorithm variable;

[0087] Therefore, the coordinates of the control points of the cubic B-spline curve are inversely calculated according to the coordinates of the key points, the B-spline basis recursive algorithm and the parameterized values ​​in step S202 as follows:

[0088] According to the formula [x k (i)y k (i)]=A - *[x(i)y(i)] calculates the coordinates of the control point;

[0089] Where: x k (i) and y k (i) are the horizontal and vertical coordinates of the ith control point; x(i) and y(i) are the horizontal and vertical coordinates of the ith key point;

[0090] A - is the inverse matrix of the inverse matrix A(i,j);

[0091]

[0092] The step S203 described above of obtaining the ideal planting trajectory according to the coordinates of the control points specifically includes the following steps S301-S303:

[0093] Step S301, according to the formula Calculate the coordinates of the jth end point in the i-th track segment, where: X(i,j) and Y(i,j) are the horizontal and vertical coordinates of the jth end point in the i-th track segment, respectively. is the variable of the end point recursive algorithm, and m is the number of parts into which the i-th trajectory is divided;

[0094] In this step, it is assumed that the i-th trajectory is divided into m parts, and the coordinates of the end point of each part are calculated.

[0095] Step S302, generating the i-th track according to the coordinates of all the end points;

[0096] Step S303, obtaining the ideal planting trajectory according to all the trajectories.

[0097] The above step S104, based on the ideal planting trajectory, calculates the lengths and postures of the two rods in the preset two-rod mechanism model, and calculates the total transmission ratio in the seedling removal process, specifically includes the following steps S401-S403:

[0098] Step S401, according to the formula Calculate the lengths of the two rods in the two-rod mechanism model, where: d max is the distance between the point farthest from the rotation center in the ideal planting trajectory and the rotation center; d min is the distance between the point closest to the rotation center in the ideal planting trajectory and the rotation center;

[0099] Step S402: according to the posture matrix The posture of the two-bar mechanism model is calculated using an iterative method;

[0100] In this step, the calculation process of the posture matrix is ​​as follows:

[0101] according to Figure 3 It can be seen that the end point Y(x i ,y i ) is specifically expressed as:

[0102]

[0103] The above formula is converted into function form: f1(δ,θ) and f2(δ,θ) are the deviation functions of the end points on the horizontal and vertical axes respectively.

[0104] The approximate solution of f(x)=0 is determined by Taylor expansion f(x)≈f(x0)+f′(x0)(x-x0):

[0105] The above posture matrix is ​​constructed f1′(δ) and f1′(θ) are the partial derivatives of f1(δ,θ) with respect to variables δ and θ respectively, and f′2(δ) and f′2(θ) are the partial derivatives of f2(δ,θ) with respect to variables δ and θ respectively.

[0106] According to the above attitude matrix, the iterative method is used to calculate and finally obtain the corresponding arm rotation angle δ and planetary gear rotation angle θ at any end point.

[0107] Step S403, calculating the total transmission ratio i 13 =dδ / dθ.

[0108] Assume that the intermediate gear rotation angle is β, and the transmission ratio between the sun gear and the intermediate gear is i 12 , the transmission ratio between the intermediate wheel and the planetary wheel is i 23 , the relationship between the transmission ratio, the rotation angle and the corresponding radial direction is: Among them: l3 is the center distance between adjacent gears, that is, l1 / 2; r1(δ) is the radial direction corresponding to the sun gear at an angle of δ; r3(θ) is the radial direction corresponding to the planetary gear at an angle of θ.

[0109] Based on this, the planetary gear train formed by two sets of gears described in step S104 above allocates two-stage transmission ratios to obtain a secondary special-shaped non-circular gear transmission transplanting seedling mechanism, which specifically includes the following steps S501-S505:

[0110] Step S501, optimizing and calculating the optimal solution according to the transmission ratio distribution formula and the constraint conditions, and obtaining the relationship between the intermediate wheel rotation angle β and the sun wheel rotation angle δ; wherein: the transmission ratio distribution formula is The restriction is It represents one rotation of the intermediate wheel; i 12 (δ) is the transmission ratio between the sun gear and the intermediate gear; k(δ) is a continuous piecewise function related to the sun gear rotation angle δ, and k(δ) is the optimized variable; i 13 (δ) is the total transmission ratio of the planetary gear train; β(δ) is the function of the intermediate gear rotation angle with respect to the sun gear rotation angle δ;

[0111] Step S502, according to Solve to get the radial direction of the sun gear at angle δ;

[0112] Step S503: according to r 21 (β) = l3-r1(δ) Solve to get the radial direction of the intermediate wheel meshing with the sun gear;

[0113] Step S504, according to Solve to get the radial direction of the planetary gear at angle θ; where i 23 =i 13 / i 12 ;

[0114] Step S505: according to r 23 (β)=l3-r3(θ) is solved to obtain the radial direction of the intermediate wheel meshing with the planetary gear.

[0115] The present invention also provides a design system 600 (hereinafter referred to as: design system 600) for a secondary special-shaped non-circular gear transmission transplanting and seedling-picking mechanism. The design system 600 may include or be divided into one or more program modules. One or more program modules are stored in a storage medium and executed by one or more processors to complete the present invention and realize the above-mentioned design method of the secondary special-shaped non-circular gear transmission transplanting and seedling-picking mechanism. The program module referred to in the embodiment of the present invention refers to a series of computer program instruction segments that can perform specific functions, and is more suitable for describing the execution process of the design method of the secondary special-shaped non-circular gear transmission transplanting and seedling-picking mechanism in a storage medium than the program itself. The following description will specifically introduce the functions of each program module of this embodiment. Figure 7 As shown, it includes:

[0116] The acquisition module 601 is used to acquire the key points of the transplanting and seedling taking operation; here, the data of the key points are input by the user.

[0117] A trajectory generation module 602, which is used to interpolate based on the key points to obtain an ideal planting trajectory;

[0118] A first calculation module 603, which is used to calculate the length and posture of two rods in a preset two-rod mechanism model based on the ideal planting trajectory, and calculate the total transmission ratio in the seedling removal process;

[0119] The second calculation module 604 is used to allocate two-stage transmission ratios based on the planetary gear train formed by two sets of gears to obtain a secondary special-shaped non-circular gear transmission transplanting and seedling taking mechanism.

[0120] The first calculation module 603 includes:

[0121] Rod length calculation module, according to the formula Calculate the lengths of the two rods in the two-rod mechanism model, where l1 and l2 are the lengths of the two rods respectively; d max is the distance between the point farthest from the rotation center in the ideal planting trajectory and the rotation center; d min is the distance between the point closest to the rotation center in the ideal planting trajectory and the rotation center;

[0122] The posture calculation module calculates the posture parameters δ and θ of the two-bar mechanism model by using an iterative method according to the posture matrix, where δ and θ are two parameters representing the posture of the two-bar mechanism model;

[0123] Transmission ratio calculation module, calculates the total transmission ratio i 13 =dδ / dθ;

[0124] The posture matrix is: in: f1(δ,θ) and f2(δ,θ) are the deviation functions of the end points on the horizontal and vertical axes respectively; i With y i are the horizontal and vertical coordinates of the end points respectively; f1′(δ) and f1′(θ) are the partial derivatives of f1(δ,θ) with respect to the variables δ and θ respectively; f′2(δ) and f′2(θ) are the partial derivatives of f2(δ,θ) with respect to the variables δ and θ respectively.

[0125] Other contents of the design method for realizing the above-mentioned secondary special-shaped non-circular gear transmission transplanting seedling picking mechanism based on the design system 600 have been introduced in detail in the previous embodiments. Please refer to the corresponding contents in the previous embodiments and will not be repeated here.

[0126] In order to facilitate operation and obtain intuitive results, a visual interface can be set for the above design system 600, such as Figure 8 As shown, the user can input data of 12 key points and perform calculations. Fig. 9 The result calculated based on the input key point data and the actual fitted static trajectory, Fig.10 It is the dynamic trajectory of the transplanting and seedling taking mechanism during operation.

[0127] The transplanting trajectory obtained by the design method and system of the secondary profiled non-circular gear transmission transplanting seedling picking mechanism of the present invention is closer to the requirements of the ideal trajectory, while the planetary gear system is stable, and the accuracy and reliability of the seedling picking mechanism are high. In addition, the algorithm of the present invention is simple and the calculation efficiency is high.

[0128] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. The design method of the secondary special-shaped non-circular gear transmission transplanting seedling mechanism includes: Get the key points of transplanting and seedling taking operations; Interpolation is performed based on the key points to obtain an ideal planting trajectory; Based on the ideal planting trajectory, the lengths and postures of the two rods in the preset two-rod mechanism model are calculated, and the total transmission ratio in the seedling removal process is calculated; Based on the planetary gear train formed by two sets of gears, two-stage transmission ratio is allocated to obtain a secondary special-shaped non-circular gear transmission transplanting and seedling taking mechanism; The step of calculating the lengths and postures of two rods in a preset two-rod mechanism model based on the ideal planting trajectory, and calculating the total transmission ratio in the seedling removal process includes: According to the formula Calculate the lengths of the two rods in the two-rod mechanism model, where l1 and l2 are the lengths of the two rods respectively; d max is the distance between the point farthest from the rotation center in the ideal planting trajectory and the rotation center; d min is the distance between the point closest to the rotation center in the ideal planting trajectory and the rotation center; Calculate the posture parameters δ and θ of the two-bar mechanism model by using an iterative method according to the posture matrix, where δ and θ are two parameters representing the posture of the two-bar mechanism model; Calculate the total transmission ratio i 13 =dδ / dθ; Features: The posture matrix is: in: f1(δ,θ) and f2(δ,θ) are the deviation functions of the end points on the horizontal and vertical axes respectively; i With y i are the horizontal and vertical coordinates of the end points respectively; f1′(δ) and f1′(θ) are the partial derivatives of f1(δ,θ) with respect to the variables δ and θ respectively; f′2(δ) and f′2(θ) are the partial derivatives of f2(δ,θ) with respect to the variables δ and θ respectively.

2. The design method of the secondary special-shaped non-circular gear transmission transplanting seedling mechanism according to claim 1 is characterized in that: The planetary gear train formed by two sets of gears is allocated with two-stage transmission ratios to obtain a secondary special-shaped non-circular gear transmission transplanting and seedling taking mechanism, which includes: The optimal solution is obtained by optimizing the calculation according to the transmission ratio distribution formula and the restriction conditions, and the relationship between the intermediate wheel rotation angle β and the sun wheel rotation angle δ is obtained; wherein: the transmission ratio distribution formula is The restriction is i 12 (δ) is the transmission ratio between the sun gear and the intermediate gear; k(δ) is a continuous piecewise function related to the sun gear rotation angle δ, and k(δ) is the optimized variable; i 13 (δ) is the total transmission ratio of the planetary gear train; β(δ) is the function of the intermediate gear rotation angle with respect to the sun gear rotation angle δ; according to Solve to get the radial direction of the sun gear at angle δ; where l3 is the center distance between adjacent gears; According to r 21 (β) = l3-r1(δ) Solve to get the radial direction of the intermediate wheel meshing with the sun gear; according to Solve to get the radial direction of the planetary gear at angle θ; where i 23 is the transmission ratio between the intermediate gear and the planetary gear, and i 23 =i 13 / i 12 ; According to r 23 (β)=l3-r3(θ) is solved to obtain the radial direction of the intermediate wheel meshing with the planetary gear.

3. The design method of the secondary special-shaped non-circular gear transmission transplanting seedling mechanism according to claim 1 is characterized in that: The interpolation based on the key points to obtain the ideal planting trajectory includes: Calculate all chord lengths d(i) according to the coordinates of the key points, and use a parameterized formula to calculate the ratio of the first i segments of chord length to the total chord length to obtain a parameterized value; wherein: the chord length d(i) is the distance between the i-th key point and the i+1-th key point, i=1,2…a, a is the total number of key points; Inversely calculate the coordinates of the control points of the cubic B-spline curve according to the coordinates of the key points, the B-spline basis recursive algorithm and the parameterized value; The ideal planting trajectory is obtained according to the coordinates of the control points.

4. The design method of the secondary special-shaped non-circular gear transmission transplanting seedling mechanism according to claim 3 is characterized in that: The parameterization formula is: Where: u(i) is the ratio of the sum of the lengths of the first i chords to the total length of all chords; represents the length of the jth chord; x(j) and y(j) are the horizontal and vertical coordinates of the jth key point respectively.

5. The design method of the secondary special-shaped non-circular gear transmission transplanting seedling mechanism according to claim 4 is characterized in that: The B-spline basis recursion algorithm is: Among them, N i,k (t) is the k-th B-spline basis function of the i-th segment, and u i is a node that belongs to the real number sequence U, and u i ≤u i+1 ; t is the recursive algorithm variable; The coordinates of the control points of the cubic B-spline curve are inversely calculated based on the coordinates of the key points, the B-spline basis recursive algorithm and the parameterized value as follows: According to the formula [x k (i) y k (i)]=A - *[x(i) y(i)] calculates the coordinates of the control point; Where: x k (i) and y k (i) are the horizontal and vertical coordinates of the i-th control point; A - is the inverse matrix of the inverse matrix A(i,j); Inverse Matrix 6. The design method of the secondary special-shaped non-circular gear transmission transplanting seedling mechanism according to claim 3 is characterized in that: The step of obtaining the ideal planting trajectory according to the coordinates of the control points comprises: According to the formula Calculate the coordinates of the jth end point in the i-th track segment, where: X(i,j) and Y(i,j) are the horizontal and vertical coordinates of the jth end point in the i-th track segment, respectively. is the variable of the end point recursive algorithm, and m is the number of parts into which the i-th trajectory is divided; Generate the i-th trajectory according to the coordinates of all the end points; The ideal planting trajectory is obtained according to all the trajectories.

7. The design system of the secondary special-shaped non-circular gear transmission transplanting seedling mechanism includes: An acquisition module is used to acquire key points of transplanting and seedling taking operations; A trajectory generation module, which is used to interpolate based on the key points to obtain an ideal planting trajectory; A first calculation module, which is used to calculate the length and posture of two rods in a preset two-rod mechanism model based on the ideal planting trajectory, and calculate the total transmission ratio in the seedling removal process; The second calculation module is used to allocate two-stage transmission ratios based on the planetary gear train formed by two sets of gears to obtain a secondary special-shaped non-circular gear transmission transplanting and seedling taking mechanism; The first calculation module includes: Rod length calculation module, according to the formula Calculate the lengths of the two rods in the two-rod mechanism model, where l1 and l2 are the lengths of the two rods respectively; d max is the distance between the point farthest from the rotation center in the ideal planting trajectory and the rotation center; d min is the distance between the point closest to the rotation center in the ideal planting trajectory and the rotation center; The posture calculation module calculates the posture parameters δ and θ of the two-bar mechanism model by using an iterative method according to the posture matrix, where δ and θ are two parameters representing the posture of the two-bar mechanism model; Transmission ratio calculation module, calculates the total transmission ratio i 13 =dδ / dθ; Features: The posture matrix is: in: f1(δ,θ) and f2(δ,θ) are the deviation functions of the end points on the horizontal and vertical axes respectively; i With y i are the horizontal and vertical coordinates of the end points respectively; f1′(δ) and f1′(θ) are the partial derivatives of f1(δ,θ) with respect to the variables δ and θ respectively; f′2(δ) and f′2(θ) are the partial derivatives of f2(δ,θ) with respect to the variables δ and θ respectively.

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