Three-axis positioning rubber tapping control method and three-axis positioning rubber tapping device

Abstract

The invention discloses a three-axis positioning rubber tapping control method and a three-axis positioning rubber tapping device, and relates to the technical field of rubber tapping machines. According to the coordinate of the current position point and the coordinate of the target position point, the three-axis displacement of rubber tapping from the current position point to the target position point is calculated, the three-axis rubber tapping mechanism is controlled according to the three-axis displacement, and the rubber tapping tool bit works to the target position point. According to the rubber tapping device, automatic control over rubber tapping work is achieved based on a three-axis positioning mode, compared with a tree-winding annular positioning mode, adaptability and accuracy are improved, a tree-winding annular positioning structure is not needed, the structure of the rubber tapping device is simplified, and cost is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of rubber tapping machines, and particularly to a three-axis positioning rubber tapping control method and a three-axis positioning rubber tapping device. Background Art

[0002] Natural rubber is an important industrial raw material and strategic material. It is listed together with steel, petroleum, and coal as the four major industrial raw materials in modern society and is widely used in industries, national defense, medicine, and other fields. Natural rubber is sourced from rubber trees and is obtained by processing the latex collected after rubber tapping. Rubber tapping refers to cutting the bark of rubber trees to collect the latex flowing out from the latex ducts and flowing down along the tapping surface. This process is a key link in obtaining natural rubber. In China, there are strict and clear technical requirements for rubber tapping operations on rubber trees. Tapping too deeply will damage the rubber trees, while tapping too shallowly will not effectively damage a sufficient number of latex ducts, resulting in an inability to guarantee the yield.

[0003] Currently, most mainstream automated rubber tapping equipment uses a tree-surrounding circular positioning structure and uses a profiling method to control the tapping depth. This mode has the defects of a complex overall structure of the mechanism, low reliability, high cost, and still insufficient adaptability. Summary of the Invention

[0004] The purpose of the present application is to provide a three-axis positioning rubber tapping control method and a three-axis positioning rubber tapping device to improve the adaptability and accuracy of rubber tapping operations, simplify the structure of the rubber tapping device, and reduce costs.

[0005] To achieve the above purpose, the present application provides the following solutions.

[0006] In a first aspect, the present application provides a three-axis positioning rubber tapping control method, including:

[0007] Using the least squares method to obtain the fitted rubber tapping trajectory of the rubber tree;

[0008] Discretizing the fitted rubber tapping trajectory to obtain a position point sequence composed of a plurality of discrete position points;

[0009] Taking the first position point in the position point sequence as the current position point, and taking the next position point of the current position point in the position point sequence as the target position point;

[0010] Calculating the three-axis displacement from the current position point to the target position point according to the coordinates of the current position point and the coordinates of the target position point;

[0011] Control the three-axis rubber tapping mechanism according to the three-axis displacement, so that the rubber tapping cutter head works to the target position point, take the target position point as the current position point, and obtain the next position point of the current position point in the position point sequence as the target position point, and return to the step of "calculating the three-axis displacement from the current position point to the target position point according to the coordinates of the current position point and the target position point", until the rubber tapping reaches the last position point in the position point sequence.

[0012] In a second aspect, the present application provides a three-axis positioning rubber tapping device, which includes: a moving platform, a three-axis rubber tapping mechanism and a control system; the three-axis rubber tapping mechanism is arranged on the moving platform, and the control end of the three-axis rubber tapping mechanism is connected to the control system; the control system is used to control the three-axis rubber tapping mechanism to perform rubber tapping by using the above three-axis positioning rubber tapping control method.

[0013] According to the specific embodiments provided by the present application, the present application has the following technical effects.

[0014] The present application provides a three-axis positioning rubber tapping control method and a three-axis positioning rubber tapping device. The present application calculates the three-axis displacement from the current position point to the target position point according to the coordinates of the current position point and the target position point, and controls the three-axis rubber tapping mechanism according to the three-axis displacement, so that the rubber tapping cutter head works to the target position point. The present application realizes the automatic control of the rubber tapping work based on the three-axis positioning method. Compared with the method of circular positioning around the tree, both the adaptability and the accuracy are improved, and there is no need for a circular positioning structure around the tree, which simplifies the structure of the rubber tapping device and reduces the cost. Description of the Drawings

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0016] Figure 1 It is a schematic flow chart of a three-axis positioning rubber tapping control method provided by an embodiment of the present application.

[0017] Figure 2 It is a schematic principle diagram of a three-axis positioning rubber tapping control method provided by an embodiment of the present application.

[0018] Figure 3 It is a schematic structural diagram of a three-dimensional cylindrical polar coordinate system provided by an embodiment of the present application.

[0019] Figure 4This is the overall structure diagram of a three-axis positioning rubber tapping device provided by an embodiment of the present application.

[0020] Figure 5 This is the top view of a three-axis positioning rubber tapping device provided by an embodiment of the present application.

[0021] Figure 6 This is the schematic structural diagram of a three-axis rubber tapping mechanism provided by an embodiment of the present application.

[0022] Explanation of reference numerals:

[0023] 1. Frame main body; 2. Traveling mechanism; 3. Steering mechanism; 4. Suspension mechanism; 5. Three-axis rubber tapping mechanism; 6. Y-axis linear module; 7. First connecting piece; 8-1. X-axis linear module; 8-2. Z-axis linear module; 9. Profile frame; 10. Rubber tapping cutter head; 11. Second connecting piece; 12. Limit switch; 13. Linear guide rail; 14. Extended nut and washer; 15. Depth camera. Detailed implementation manners

[0024] Next, the technical solutions in the embodiments of the present application will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0025] To make the above objects, features, and advantages of the present application more obvious and understandable, the present application will be further described in detail below with reference to the accompanying drawings and specific implementation manners.

[0026] In an exemplary embodiment, as Figure 1 and Figure 2 shown, a three-axis positioning rubber tapping control method is provided, including the following steps:

[0027] Step 101: Use the least squares method to obtain the fitted rubber tapping trajectory of the rubber tree.

[0028] Step 102: Discretize the fitted rubber tapping trajectory to obtain a position point sequence composed of multiple discrete position points.

[0029] Step 103: Take the first position point in the position point sequence as the current position point, and take the next position point of the current position point in the position point sequence as the target position point.

[0030] Step 104: Calculate the three-axis displacement from the current position point to the target position point according to the coordinates of the current position point and the target position point.

[0031] Step 105: Control the three-axis rubber tapping mechanism according to the three-axis displacement, so that the rubber tapping knife head works to the target position point, take the target position point as the current position point, and obtain the next position point of the current position point in the position point sequence as the target position point, and return to the step of "calculating the three-axis displacement from the current position point to the target position point according to the coordinates of the current position point and the target position point" until the rubber tapping reaches the last position point in the position point sequence.

[0032] Implementing the above Step 101 - Step 105 can achieve the automatic control of the rubber tapping work. Compared with the way of circular positioning around the tree, both the adaptability and accuracy are improved, and there is no need for a circular positioning structure around the tree, which simplifies the structure of the rubber tapping device and reduces the cost.

[0033] In another exemplary embodiment, during the rubber tapping work, the rubber tapping trajectory is a curve distributed on the surface of the tree trunk. However, since the trunk of the rubber tree is not a standard circle or ellipse, the rubber tapping trajectory is also an irregular approximate circular arc curve. Therefore, in order to ensure precise depth control throughout the rubber tapping process, the following method is used to obtain an accurate rubber tapping trajectory: First, obtain the coordinates of a series of points on a limited number of target rubber tapping trajectories, and then fit these points to generate a continuous rubber tapping trajectory, that is, the fitted rubber tapping trajectory.

[0034] Since the trunk of the rubber tree is cylindrical in shape, it is more intuitive to use a three-dimensional cylindrical polar coordinate system to describe the trajectory distributed on the trunk, and the coordinate representation of points is also simpler, and the subsequent conversion to the Cartesian coordinate system is also very simple. As Figure 3 shown, the horizontal projection plane of the trajectory is at the height of the starting point of the trajectory, O is the center of the coordinate system, P is any point on the trajectory, (r, θ) is the position of P on the horizontal projection plane, and z represents its height relative to the horizontal projection plane. Therefore, (r, θ, z) can represent the position of point P relative to the coordinate origin O.

[0035] After obtaining the coordinates of a series of trajectory points, first perform least squares fitting.

[0036] Suppose there are n data points (r i , θ i , z i )(i = 1, 2,..., n), determine the fitting function:

[0037]

[0038] Construct the error function E. For each data point, calculate the difference e between its actual z value z i and the value f(r i and θ i ) at the corresponding r i , θ i ) of the fitting functioni = z i - f(r i , θ i ). And in order to comprehensively consider the errors of all data points and avoid the problem of positive and negative errors canceling each other out, the form of the square of the error is adopted. The error function E is defined as the sum of the squares of the errors of all data points, that is

[0039]

[0040] where E is the error function, e i is the fitting error of the i-th point on the target tapping trajectory, n is the number of points on the target tapping trajectory, z i is the longitudinal coordinate of the i-th point on the target tapping trajectory in the three-dimensional cylindrical polar coordinate system, f(r i , θ i ) is the longitudinal fitting coordinate of the i-th point on the target tapping trajectory, r i is the radial coordinate of the i-th point on the target tapping trajectory in the three-dimensional cylindrical polar coordinate system, θ i is the angular coordinate of the i-th point on the target tapping trajectory in the three-dimensional cylindrical polar coordinate system, a jk is the (j, k)-th coefficient in the fitting function, j, k = 0, 1, 2,..., m, and m is the degree of the polynomial in the least squares fitting. Generally, in order to fit a slightly complex curve, a cubic polynomial fitting is generally used, that is, m takes 3.

[0041] Take the partial derivative of E with respect to a ij For example, for a (p, q = 0, 1,..., m), there is: pq (p, q = 0, 1,..., m), there is:

[0042]

[0043] Let all to obtain a system of equations containing equations. Solve the system of equations and obtain the coefficient a ij . Substitute the obtained coefficient into the fitting function, that is, Equation (1), to obtain the final trajectory.

[0044] In another exemplary embodiment, step 101 above specifically includes the following steps 201-step 203.

[0045] Step 201, obtain a preset number of points on the target tapping trajectory of the rubber tree.

[0046] Step 202, with the center of the cross-section of the rubber tree where the starting point of the target tapping trajectory of the rubber tree is located as the origin, and the height direction of the rubber tree as the z-axis direction, establish a three-dimensional cylindrical polar coordinate system, as Figure 3 shown.

[0047] Step 203: Determine the coordinates of a preset number of points on the target tapping trajectory in the three-dimensional cylindrical polar coordinate system.

[0048] Step 204: Obtain the fitted tapping trajectory of the rubber tree by using the least squares method based on the coordinates of a preset number of points on the target tapping trajectory in the three-dimensional cylindrical polar coordinate system.

[0049] Among them, Step 204 can be replaced by the following Steps 301 - 303.

[0050] Step 301: Construct a fitting function as shown in Equation (1).

[0051] Step 302: Construct an error function as shown in Equation (2) according to the fitting function and the coordinates of a preset number of points on the target tapping trajectory in the three-dimensional cylindrical polar coordinate system.

[0052] Step 303: Let the partial derivative of the error function with respect to each coefficient in the fitting function be equal to 0, and construct a system of coefficient equations as shown in Equation (3).

[0053] Step 304: Solve the system of coefficient equations by using the least squares method to obtain the values of each coefficient in the fitting function.

[0054] Step 305: Substitute the values of each coefficient into the fitting function to obtain the fitted tapping trajectory.

[0055] In another exemplary embodiment, since the movement of the stepper motor is discrete, continuous trajectory data needs to be discretized into a series of tiny step lengths. Determine an appropriate step length accuracy, and decompose the trajectory data into discrete position points according to the step length. Each position point corresponds to the target position that the stepper motor needs to reach. The above Step 101 can be replaced by the following Steps 401 - 403.

[0056] Step 401: Decompose the fitted tapping trajectory into multiple discrete position points according to the preset step length.

[0057] Step 402: Determine the coordinates of each discrete position point in the Cartesian coordinate system by using the coordinate transformation formula according to the coordinates of each discrete position point in the three-dimensional cylindrical polar coordinate system.

[0058] Step 403: Construct the sequence of position points based on the coordinates of each discrete position point in the Cartesian coordinate system.

[0059] In the above step 402, since the three linear modules constituting the three-axis mechanism are orthogonal to each other in pairs, a positioning and rubber tapping method based on the Cartesian coordinate system is formed. Therefore, in order to facilitate its control, the obtained fitting rubber tapping trajectory based on the three-dimensional cylindrical polar coordinate system (r, θ, z) needs to be transformed onto the Cartesian coordinate system (x, y, z).

[0060] The coordinate conversion formula between the three-dimensional cylindrical polar coordinate system and the Cartesian coordinate system is as follows:

[0061]

[0062] Replace r and θ in the original fitting function with x and y, that is to obtain

[0063]

[0064] In another exemplary embodiment, in the above step 104, according to the parameters of the lead screw module, the Cartesian coordinate values are converted into the corresponding number of steps of the stepper motor. Calculate the number of steps that the stepper motor needs to rotate on each axis, and determine the movement direction and number of steps of each axis from the current position point to the target position point.

[0065] First, determine the important motor parameters, including the lead screw pitch P, the step angle θ, the driver subdivision multiple N, and so on. Assume that the coordinates of the target position point in the Cartesian coordinate system are (x, y, z), and the coordinates of the current position point in the Cartesian coordinate system are (x 0 , y 0 , z 0 ), then the displacements of the three axes are Δx = x - x 0 , Δy = y - y 0 , Δz = z - z 0 , with the unit of mm.

[0066] Next, convert the number of steps of each axis: According to the lead screw pitch and the angle that the motor rotates per pulse, calculate the number of steps that the stepper motor on each axis needs to rotate. Since the lead screw pitch P represents the distance that the slider moves when the lead screw rotates 360°, and the angle that the motor rotates per pulse is θ / N, the calculation formula for the number of steps required for each axis is as follows:

[0067]

[0068] Exemplarily, assume that the motor parameters of the stepper motors on the three axes are the same, as shown in Table 1.

[0069] Table 1 Stepper motor parameter table

[0070] Lead of the lead screw (mm) Diameter of the lead screw mm Maximum stroke mm Step angle ° Driver subdivision multiple 1 6 200 1.8 16

[0071] Then, perform motion cycle control.

[0072] Take out the coordinate data of the next position point from the position point sequence, convert it into the target number of steps of the stepper motor, and set it into the corresponding target position variable.

[0073] Use the speed planning algorithm to calculate the appropriate pulse frequency and determine the movement speed of the stepper motor. Here, the simplest calculation algorithm based on the target speed is used: First, determine the target speed v of each axis of the three-axis rubber tapping mechanism, with the unit of mm / s. Given the lead screw pitch P, the step angle θ, and the subdivision multiple N, the number of steps per revolution of the motor n = 360 / (θ / N). According to the relationship between speed, displacement, and time v = s / t, in the lead screw drive, the distance that the motor drives the slider to move per revolution is the lead screw pitch P. Then the number of revolutions per second of the motor f 1 = v / P. Converted to the number of pulses required per second, that is, the pulse frequency f = f 1 ×n = (v / P)×(360 / (θ / N)). For example, the target speed of the x-axis is v x = 10mm / s, the lead screw pitch P = 1mm, the step angle θ = 1.8°, and the subdivision multiple N = 16. Then the pulse frequency f of the x-axis x = (10 / 1)×(360 / (1.8 / 16)) = 32000Hz.

[0074] STM32 generates a pulse signal with a specified frequency through the timer, and sends the pulse signal to the stepper motor starters of the three linear lead screw modules according to the calculated number of steps and direction. The driver drives the stepper motor to rotate according to the received signal, so that the rubber tapping knife head of the three-axis rubber tapping mechanism moves to the target position point. And after sending the corresponding number of pulses for each position point, update the current position variable to make it consistent with the actual reached position.

[0075] In another exemplary embodiment, the above step 105 can be replaced by the following steps 501-step 506.

[0076] Step 501, calculate the number of steps that the three-axis stepper motor of the three-axis rubber tapping mechanism needs to rotate according to the three-axis displacement.

[0077] Step 502, emit pulse signals to control the three-axis stepper motor to rotate the number of steps it needs to rotate respectively, and obtain the current position where the rubber tapping knife head is located.

[0078] Step 503, calculate the three-axis position difference and distance between the current position where the rubber tapping knife head is located and the target position point.

[0079] Step 504, judge whether the absolute value of the distance is greater than the preset error threshold to obtain a judgment result.

[0080] Step 505, if the judgment result is yes, calculate the number of steps that the three-axis stepping motors of the three-axis rubber tapping mechanism need to rotate according to the three-axis position difference, and return to the step of "transmitting pulse signals to control the three-axis stepping motors to rotate the required number of steps respectively, and obtaining the current position of the rubber tapping knife head".

[0081] Step 506, if the judgment result is no, determine that the rubber tapping knife head of the three-axis rubber tapping mechanism works to the target position point.

[0082] In an exemplary embodiment, a three-axis positioning rubber tapping device is provided, including: a mobile platform, a three-axis rubber tapping mechanism 5, and a control system; the three-axis rubber tapping mechanism 5 is arranged on the mobile platform, and the control end of the three-axis rubber tapping mechanism 5 is connected to the control system; the control system is used to control the three-axis rubber tapping mechanism 5 to perform rubber tapping by using the three-axis positioning rubber tapping control method in the above embodiment.

[0083] As Figure 4 and Figure 5 shown, the above mobile platform includes: a vehicle frame main body 1, a traveling mechanism 2, a steering mechanism 3, and a suspension mechanism 4. The mobile platform moves along a set route by the rotation of the DC reduction motor of the traveling mechanism 1 to drive the wheels to move accordingly. The steering motor of the steering mechanism 3 controls the steering angle in real time so that the mobile platform moves in front of the rubber tree and makes the circular groove of the mobile platform closely adhere to the rubber tree.

[0084] As Figure 6 shown, the above three-axis rubber tapping mechanism 5 includes an x-axis linear module 8-1, a y-axis linear module 6, a z-axis linear module 8-2, and a rubber tapping knife head 10. The host computer is connected to the control system through a serial port, controls the three-axis rubber tapping mechanism 5 to start, and each axis linear module starts to reset and moves to the position of the starting limit switch 12 at the starting point. The signal is fed back to the host computer through the control system, and the movement stops.

[0085] Exemplarily, the above mobile platform is an eight-motor mobile platform, and the three-axis rubber tapping mechanism 5 is installed on the eight-motor mobile platform and mainly consists of three linear modules (x-axis linear module 8-1, y-axis linear module 6, z-axis linear module 8-2) and several supports and connectors. The three linear modules are orthogonal to each other in pairs and respectively control the movement in three different coordinate directions in space, so that the rubber tapping knife head 10 fixed at the end can realize arbitrary movement in space. The depth camera 15 is responsible for obtaining the white rubber marks formed by the latex flowing down along the cut line after the last rubber tapping on the rubber tree trunk, and performing segmentation, extraction, and fitting on the collected images to obtain the final rubber tapping trajectory, and controlling the motor of the linear module to drive the rubber tapping knife head 10 to complete the rubber tapping operation according to the generated trajectory.

[0086] Further, the above eight-motor mobile platform is installed on both sides of the vehicle frame body 1 by four identical suspension mechanisms 4. The steering mechanism 3 is installed on the lower connecting plate of the suspension mechanism 4. The traveling mechanism 2 is locked with the flange coupling of the steering mechanism 3 by screws. Moreover, a threaded hole is opened at the end of the reducer shaft of the steering mechanism 3 and is locked and connected with the driving connecting plate through an end retaining ring.

[0087] Further, the overall structure of the three-axis rubber tapping mechanism 5 includes three linear modules with a 200-mm stroke, namely, the x-axis linear module 8-1, the y-axis linear module 6, and the z-axis linear module 8-2, linear guides 13, multiple profile frames 9, several connecting pieces, a rubber tapping cutter head 10, and a depth camera 15. Among them, the linear guide 13 and one linear module are arranged parallel to each other and vertically on two support columns on the profile frame 9. And in order to make the sliders of the two be on the same plane for installing another horizontally placed linear module, an extended nut and washer 14 are installed at the connection between the linear guide 13 and the aluminum profile to make up for the height difference with the corresponding linear module. Connecting pieces (i.e., the first connecting piece 7 and the second connecting piece 11) are respectively installed on the linear guide 13 on the x-axis linear module 8-1 and the slider of the corresponding z-axis linear module 8-2 to install the z-axis linear module 8-2. The slider of the z-axis linear module 8-2 is directly connected and fixed to the y-axis linear module that controls the feeding depth by bolts. The rubber tapping cutter head 10 is installed at the end of the aluminum profile for extending the distance and is installed together on the slider of the y-axis linear module for depth control.

[0088] Further, in the x-axis linear module 8-1, the stepping motor drives the lead screw to rotate, thereby promoting the movement of the slider on the lead screw and pushing the z-axis linear module 8-2 fixed thereon to move in the vertical direction. The parallel linear guide 13 plays a role in support and transmission, making the movement stable and precise. Similarly, the z-axis linear module 8-2 drives the horizontal movement of the y-axis linear module fixed thereon, and the y-axis linear module drives the rubber tapping cutter head 10 fixed thereon to achieve the depth feeding movement. By superimposing the three-direction movements, the rubber tapping cutter head 10 at the end of the kinematic chain can be moved arbitrarily within a limited space.

[0089] The depth camera 15 on the three-axis rubber tapping mechanism 5 collects the color and depth information of the tree trunk, obtains the target rubber tapping trajectory through image processing and other means, and stores it. Specifically, it includes a trajectory recognition method based on depth gradient change. The specific steps are as follows: First, the depth camera takes a depth map; quickly removes the background according to the depth difference between the environment and the tree trunk to determine the tree trunk contour; calculates the depth gradient change of each point in the central longitudinal pixel column, and finds the point with the smallest depth gradient as the roi center; extracts the roi within a suitable range; traverses the roi area horizontally, finds the point with the smallest depth gradient in each set of longitudinal column pixel points, and smooths the noise points according to the longitudinal distance of adjacent points; all the extracted and adjusted target points form the rubber tapping trajectory point cloud; perform least squares fitting on the point cloud to obtain an accurate and continuous rubber tapping trajectory; the series of data point coordinates obtained after discretizing the fitting curve are stored in the form of a text file (such as a csv file), and then the data is transmitted to the STM32 using serial communication and parsed on the STM32.

[0090] Specifically, the host computer controls the three-axis rubber tapping mechanism 5, drives the rubber tapping cutter head 10 to move point by point along each point in the position point sequence, performs the rubber tapping operation, and resets after all are completed.

[0091] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not conflict, it should be considered as the scope described in this specification.

[0092] In this article, specific examples are used to elaborate on the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application; at the same time, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. A three-axis positioning rubber tapping control method, characterized in that: The three-axis positioning rubber tapping control method comprises: The least square method is used to obtain the fitting tapping trajectory of rubber trees; Discretizing the fitting rubber tapping trajectory to obtain a position point sequence consisting of a plurality of discrete position points; The first position point in the position point sequence is used as the current position point, and the position point next to the current position point in the position point sequence is used as the target position point; According to the coordinates of the current position point and the coordinates of the target position point, the three-axis displacement from the current position point to the target position point is calculated; The three-axis tapping mechanism is controlled according to the three-axis displacement, so that the tapping cutter head works to the target position point, the target position point is used as the current position point, and the next position point of the current position point is obtained in the position point sequence as the target position point, and the step of "calculating the three-axis displacement from the current position point to the target position point according to the coordinates of the current position point and the coordinates of the target position point" is returned until the tapping reaches the last position point in the position point sequence.

2. The three-axis positioning rubber tapping control method according to claim 1, characterized in that: The least square method is used to obtain the fitting tapping trajectory of the rubber tree, which specifically includes: Obtain a preset number of points on the target tapping trajectory of the rubber tree; A three-dimensional cylindrical polar coordinate system is established with the center of the cross section of the rubber tree where the starting point of the target tapping trajectory of the rubber tree is located as the origin and the height direction of the rubber tree as the z-axis direction; Determine the coordinates of a preset number of points on the target tapping trajectory in the three-dimensional cylindrical polar coordinate system; According to the coordinates of a preset number of points on the target tapping trajectory in the three-dimensional cylindrical polar coordinate system, the fitting tapping trajectory of the rubber tree is obtained by adopting the least squares fitting method.

3. The three-axis positioning rubber tapping control method according to claim 2 is characterized in that: According to the coordinates of a preset number of points on the target tapping trajectory in the three-dimensional cylindrical polar coordinate system, a fitting tapping trajectory of the rubber tree is obtained by least square fitting, specifically comprising: Construct the fitting function; Constructing an error function according to the fitting function and the coordinates of a preset number of points on the target tapping trajectory in the three-dimensional cylindrical polar coordinate system; Let the partial derivative of the error function with respect to each coefficient in the fitting function be equal to 0, and construct a coefficient equation group; Using the least square method to solve the coefficient equation group, and obtain the value of each coefficient in the fitting function; The values ​​of each coefficient are brought into the fitting function to obtain the fitting rubber tapping trajectory.

4. The three-axis positioning rubber tapping control method according to claim 3 is characterized in that: The error function is: Where E is the error function, e i is the fitting error of the i-th point on the target tapping trajectory, n is the number of points on the target tapping trajectory, z i is the longitudinal coordinate of the i-th point on the target tapping trajectory in the three-dimensional cylindrical polar coordinate system, f(r i ,θ i ) is the longitudinal fitting coordinate of the i-th point on the target tapping trajectory, r i is the radial coordinate of the i-th point on the target tapping trajectory in the three-dimensional cylindrical polar coordinate system, θ i is the angular coordinate of the i-th point on the target tapping trajectory in the three-dimensional cylindrical polar coordinate system, a jk is the (j, k)th coefficient in the fitting function, j, k = 0, 1, 2, ..., m, m is the degree of the polynomial in the least squares fitting.

5. The three-axis positioning rubber tapping control method according to claim 1 is characterized in that: The step of discretizing the fitting rubber tapping trajectory to obtain a position point sequence consisting of a plurality of discrete position points specifically includes: Decomposing the fitting rubber tapping trajectory into a plurality of discrete position points according to a preset step size; According to the coordinates of each discrete position point in the three-dimensional cylindrical polar coordinate system, the coordinates of each discrete position point in the Cartesian coordinate system are determined by using a coordinate conversion formula; The position point sequence is constructed based on the coordinates of each discrete position point in the Cartesian coordinate system.

6. The three-axis positioning rubber tapping control method according to claim 1 is characterized in that: The three-axis rubber tapping mechanism is controlled according to the three-axis displacement so that the rubber tapping knife head of the three-axis rubber tapping mechanism works to the target position point, specifically including: According to the three-axis displacement, the number of steps that the three-axis stepping motor of the three-axis rubber tapping mechanism needs to rotate is calculated; The pulse signals are transmitted to control the three-axis stepper motors to rotate the required number of steps and obtain the current position of the rubber tapping knife head; Calculate the three-axis position difference and distance between the current position of the rubber tapping knife head and the target position point; Determine whether the absolute value of the distance is greater than a preset error threshold, and obtain a determination result; If the judgment result is yes, the number of steps that the three-axis stepper motor of the three-axis rubber tapping mechanism needs to rotate is calculated according to the three-axis position difference, and the process returns to the step of "emitting pulse signals to control the three-axis stepper motors to rotate the required number of steps, and obtaining the current position of the rubber tapping knife head"; If the judgment result is no, it is determined that the tapping knife head of the three-axis tapping mechanism works to the target position point.

7. The three-axis positioning rubber tapping control method according to claim 6 is characterized in that: According to the three-axis displacement, the formula for calculating the number of steps that the three-axis stepping motor of the three-axis rubber tapping mechanism needs to rotate is: Among them, n x 、n y 、n z are the number of steps that the stepper motors on the x-axis, y-axis, and z-axis need to rotate, Δx, Δy, and Δz are the displacements of the x-axis, y-axis, and z-axis, respectively. x , P y , P z The screw pitch of the stepper motor for the x-axis, y-axis, and z-axis, θ x ,θ y and θ z The step angles of the stepper motors on the x-axis, y-axis, and z-axis, N x 、N y 、N z They are the driver subdivision coefficients of the stepper motor for the x-axis, y-axis, and z-axis respectively.

8. A three-axis positioning rubber tapping device, characterized in that: The three-axis positioning rubber tapping device comprises: a mobile platform, a three-axis rubber tapping mechanism and a control system; The three-axis rubber tapping mechanism is arranged on the mobile platform, and the control end of the three-axis rubber tapping mechanism is connected to the control system; The control system is used to control the three-axis tapping mechanism to perform tapping by adopting the three-axis positioning tapping control method described in any one of claims 1 to 7.

9. The three-axis positioning rubber tapping device according to claim 8, characterized in that: The three-axis rubber tapping mechanism includes: an x-axis linear module, a y-axis linear module, a z-axis linear module and a rubber tapping knife head; The x-axis linear module is movably arranged on two profile racks, and the two profile racks are fixed on the mobile platform; The z-axis linear module is movably arranged on the x-axis linear module, and the y-axis linear module is movably arranged on the z-axis linear module; The rubber tapping cutter head is arranged at the end of the y-axis linear module; The x-axis linear module, the y-axis linear module and the z-axis linear module are respectively used to control the movement of the rubber tapping knife head in the horizontal direction, the depth direction and the vertical direction.

10. The three-axis positioning rubber tapping device according to claim 9, characterized in that: The x-axis linear module, the y-axis linear module and the z-axis linear module are driven by x-axis, y-axis and z-axis stepper motors respectively.

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