An adaptive control method for the harvesting height and angle of a tobacco leaf harvesting device.

Abstract

This invention discloses an adaptive control method for the harvesting height and angle of a tobacco leaf harvesting device, comprising the following steps: (1) a lidar sensor assembly collects real-time height data of the tobacco leaves and the harvesting blade; (2) the data is transmitted to a control system for processing; (3) the required harvesting height and angle are calculated based on the height data of the tobacco leaves and the harvesting blade; (4) the control system controls four drive motors to adjust the height and angle of the harvesting blade until the harvesting blade reaches the required harvesting height and angle; (5) the control system controls the harvesting device to move so that it can contact the tobacco leaves; (6) the harvesting blade performs the harvesting operation on the tobacco leaves; (7) the control system dynamically adjusts the harvesting height and angle of the harvesting blade; (8) steps (2)-(7) are repeated to achieve adaptive control of the harvesting blade. This method can automatically adjust the harvesting height and angle of the harvesting blade, thereby improving harvesting efficiency and accuracy.

Description

Technical Field

[0001] This invention relates to the field of agricultural machinery technology, specifically to an adaptive control method for the harvesting height and angle of a tobacco leaf harvesting device. Background Technology

[0002] With the development of modern agricultural technology, tobacco plant protection and harvesting have been largely or partially mechanized. Based on the degree of automation, tobacco harvesters can be broadly classified into semi-automatic and fully automatic tobacco harvesters.

[0003] The core of a semi-automatic tobacco harvester is a self-propelled power platform. Harvesters sit in a suitable position and manually pick the leaves. Its level of automation is relatively low. Compared with purely manual harvesting, this model can save workers some physical strength, but if harvesting efficiency needs to be improved, more working positions for harvesters are required.

[0004] Fully automatic tobacco harvesters, also known as self-propelled tobacco harvesters, are highly automated. Compared to semi-automatic tobacco harvesters, their core feature lies in the design of the picking device, which uses mechanical structures to replace manual picking, reducing human damage during tobacco harvesting and transportation, and improving tobacco harvesting efficiency and curing quality.

[0005] The main difference between self-propelled tobacco harvesters lies in their harvesting devices. These differences stem primarily from the applicable tobacco varieties and the different working principles of the mechanisms. The harvesting device is the core component of the tobacco harvester and is crucial to the harvesting efficiency; therefore, there is an urgent need to develop harvesting devices adapted to the growth characteristics of tobacco. The difference in harvesting devices lies in the harvesting blades, which are the core of the device. Currently, during tobacco leaf harvesting, the harvesting height and angle of the harvesting blades usually require manual adjustment, leading to inaccurate adjustments and low efficiency. Therefore, a method is needed that can automatically adjust the harvesting height and angle of the tobacco leaf harvesting blades to improve harvesting efficiency and accuracy. Summary of the Invention

[0006] The purpose of this invention is to overcome the above-mentioned problems and provide an adaptive control method for the harvesting height and angle of a tobacco leaf harvesting device. This adaptive control method can automatically adjust the harvesting height and angle of the harvesting blades, thereby improving harvesting efficiency and accuracy.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] An adaptive control method for the harvesting height and angle of a tobacco leaf harvesting device is disclosed. The tobacco leaf harvesting device includes a frame, a harvesting mechanism, a lidar sensor assembly, and a control system. The harvesting mechanism and the lidar sensor assembly are both mounted on the frame. The harvesting mechanism includes two oppositely arranged harvesting blades for harvesting tobacco leaves and two adjustment modules for driving the harvesting blades to adjust their harvesting height and angle. Each adjustment module corresponds to one of the harvesting blades. Each harvesting blade includes a blade base and harvesting blades rotatably mounted on the blade base. Each adjustment module includes two power components respectively located at the front and rear ends of the frame. Each power component includes a rotatably mounted screw rod on the frame, a lifting platform mounted on and connected to the screw rod, and a drive motor for driving the screw rod to rotate. The two lifting platforms in each adjustment module are movably connected to the front and rear ends of the blade base. The lidar sensor assembly and the drive motor are connected to the control system.

[0009] The adaptive control method includes the following steps:

[0010] (1) Data acquisition: The lidar sensor component collects real-time data on the height of the tobacco leaves and the current height of the harvesting table;

[0011] (2) Data processing: The data collected by the lidar sensor components is transmitted to the control system for processing;

[0012] (3) Control system calculation: The control system calculates the required harvesting height and angle based on the height data of the tobacco leaves and the current height data of the harvesting table;

[0013] (4) Harvesting knife adjustment: The control system controls four drive motors, which output power to drive the screw rod to rotate, thereby driving each lifting platform to rise or fall, so as to adjust the height and angle of the knife base, and then adjust the height and angle of the harvesting knife until the harvesting knife reaches the required harvesting height and angle.

[0014] (5) Movement of the picking device: The control system controls the movement of the picking device so that the picking device can accurately contact the tobacco leaves;

[0015] (6) Harvesting operation: The harvesting knife harvests the tobacco leaves according to the calculated harvesting height and angle;

[0016] (7) Feedback adjustment: The control system dynamically adjusts the harvesting height and angle of the harvesting blades according to the actual situation during the harvesting process;

[0017] (8) Repeat the operation: Repeat steps (2)-(7) to achieve adaptive control of the picking tool.

[0018] In a preferred embodiment of the present invention, the tobacco leaf harvesting device further includes a plant straightener and a guiding and separating mechanism; the plant straightener is disposed at the front end of the frame; the plant straightener is used to straighten the tobacco plants and guide them into the harvesting mechanism; the guiding and separating mechanism is disposed on the harvesting mechanism to prevent the tobacco plants from swaying during harvesting and to separate tobacco leaves that do not need to be harvested. During the harvesting process, the tobacco leaf harvesting device moves, the plant straightener straightens the tobacco plants and guides them into the harvesting mechanism, and the guiding and separating mechanism prevents swaying and separates tobacco leaves that need to be harvested from those that do not.

[0019] In a preferred embodiment of the present invention, the harvesting blade is made of plastic, and the blade edges on both sides of the harvesting blade are sinusoidal curves. When the blade edge of one harvesting blade is convex, the corresponding position of the other harvesting blade is a groove, that is, the two harvesting blades can mesh with each other, which is beneficial for cutting tobacco leaves and thus improves the harvesting effect.

[0020] Preferably, the guiding and separating mechanism includes two guiding and separating plates, each corresponding to a harvesting cutter table, and the guiding and separating plates are fixedly installed on the cutter base. In the above structure, the two guiding and separating plates are located on both sides of the axis of symmetry along the direction of travel of the frame. The two guiding and separating plates can restrict the left and right swaying of the tobacco leaves and divide the upper and lower space into a non-harvesting area and a harvesting area. The space above the guiding and separating plates is the non-harvesting area, and the space below the guiding and separating plates is the harvesting area, so that other parts of the tobacco leaves will not be damaged when harvesting the target part of the tobacco leaves. The guiding and separating plates and the harvesting cutter move up and down and rotate synchronously. When the harvesting height changes, the tobacco leaves in the required harvesting range can still pass smoothly through the guiding and separating plates and be harvested by the harvesting cutter, ensuring the accuracy of harvesting.

[0021] Preferably, the tobacco plant lifter includes two lifting plates disposed at the front end of the frame, with a funnel-shaped guide groove formed between the two lifting plates. The two lifting plates are located on opposite sides of a symmetrical axis along the direction of travel of the frame, ensuring that the tobacco plants smoothly enter the working space of the two harvesting blades and preventing the harvesting device from pushing over or breaking the tobacco plants.

[0022] Preferably, the lidar sensor assembly includes multiple lidar sensors, which are respectively installed on the upper middle part of the front end of the frame and on the lifting platform. By using multiple lidar sensors, it is convenient to accurately collect data on tobacco plants. The lidar sensors are also used to collect the height of both ends of the harvesting table, and these lidar sensors are connected to the control system.

[0023] Preferably, the front and rear ends of the cutter base are provided with movable connecting grooves, and the lifting platform is provided with bolts, which are movably connected to the movable connecting grooves. Through this structure, the cutter base and the lifting platform are movably connected. The vertical movement of the lifting platform allows for adjustment of the height and angle of the cutter base, ultimately achieving adjustment of the harvesting height and angle of the harvesting platform.

[0024] An adaptive control method for the harvesting height and angle of a tobacco leaf harvesting device includes the following steps:

[0025] (1) Data acquisition: The lidar sensor component collects real-time data on the height of the tobacco leaves and the current height of the harvesting table;

[0026] (2) Data processing: The data collected by the lidar sensor components is transmitted to the control system for processing;

[0027] (3) Control system calculation: The control system calculates the required harvesting height and angle based on the height data of the tobacco leaves and the current height data of the harvesting table;

[0028] (4) Harvesting blade adjustment: The control system controls four drive motors, which output power to drive the screw rod to rotate, thereby driving the lifting platform to rise or fall, so as to adjust the height and angle of the blade base, and then adjust the height and angle of the harvesting blade until the harvesting blade reaches the required harvesting height and angle.

[0029] (5) Movement of the picking device: The control system controls the movement of the picking device so that the picking device can accurately contact the tobacco leaves;

[0030] (6) Harvesting operation: The harvesting knife harvests the tobacco leaves according to the calculated harvesting height and angle;

[0031] (7) Feedback adjustment: The control system dynamically adjusts the harvesting height and angle of the harvesting blades according to the actual situation during the harvesting process;

[0032] (8) Repeat the operation: Repeat steps (2)-(7) to achieve adaptive control of the picking tool.

[0033] Preferably, the control system includes a PLC controller, which controls the height and angle of the harvesting blade through an adaptive PID control strategy. This adaptive PID control strategy is applied to the PID controller, which includes a proportional unit, an integral unit, and a derivative unit. Its Laplace mathematical transfer model formula is as follows:

[0034]

[0035] Where U(s) is the driving voltage signal, E(s) is the feedback error signal, and K p K i K d Here are the control parameters of the system, where K p K is the proportionality coefficient. d K is the differential coefficient. i The integral coefficient;

[0036] By setting an integral limit, the maximum vertical displacement of the left and right ends of the harvesting blade is limited; by setting an integral separation, when the harvesting device resets its movement distance midway through harvesting, the control parameters of the PID controller from the previous control cycle are used for this calculation; by acquiring the height data of the tobacco leaves and the height of both ends of the harvesting blade in each control cycle through the lidar sensor, the tracking error of that cycle is calculated, and by combining the error increment with the three control parameters of the PID controller, the output signal of the control system is adjusted, thereby controlling the harvesting height and angle of the harvesting blade.

[0037] Preferably, the harvesting mechanism further includes a frequency converter, and the PLC controller is connected to the drive motor via the frequency converter. By setting the frequency converter, the drive motor can be controlled.

[0038] Preferably, the PLC controller and the frequency converter communicate via the CAN protocol.

[0039] Compared with the prior art, the present invention has the following advantages:

[0040] 1. The adaptive control method for the harvesting height and angle of the tobacco harvesting device in this invention, compared with the existing semi-automatic and fully automatic tobacco harvesters, has a low degree of automation and suffers from problems such as inaccurate adjustment and low efficiency. However, the adaptive control method of this application can change the height of the front and rear ends of the harvesting platform and the angle of the harvesting platform relative to the ground in real time according to the height of the tobacco leaves. This allows the harvesting mechanism to more accurately harvest the tobacco leaves from the desired parts of the stem of each tobacco plant, while reducing damage to the tobacco leaves in parts that do not need to be harvested. This greatly enhances the automation level and applicability of the tobacco harvesting mechanism.

[0041] 2. The adaptive control method for the harvesting height and angle of the tobacco leaf harvesting device in this invention can improve harvesting efficiency and accuracy by dynamically adjusting the height and angle of the harvesting blade. Attached Figure Description

[0042] Figure 1 This is a three-dimensional structural diagram of the tobacco leaf harvesting device of the present invention.

[0043] Figure 2This is a front view of the tobacco leaf harvesting device of the present invention.

[0044] Figure 3 This is a left view of the tobacco leaf harvesting device of the present invention.

[0045] Figure 4 This is a three-dimensional structural diagram of part of the harvesting mechanism and the guiding and separating mechanism in this invention.

[0046] Figure 5 This is a schematic diagram of a portion of the harvesting mechanism in this invention.

[0047] Figure 6 This is a three-dimensional structural diagram of the harvesting platform in this invention.

[0048] Figure 7 This is an adaptive PID control diagram of the harvesting height and angle based on the PLCS7-1200 controller in this invention.

[0049] Figure 8 This is a schematic diagram of the CAN protocol of the control system in this invention.

[0050] Among them, 1-frame, 2-grain lifter, 201-grain lifter board, 3-guide and divider mechanism, 301-guide divider plate, 3011-triangular guide frame, 3012-flat plate, 4-harvesting knife table, 401-knife base, 402-harvesting knife, 4021-knife edge, 5-adjustment module, 501-screw rod, 502-lifting platform, 503-drive motor, 504-reducer, 505-transmission half shaft, 506-bevel gear transmission mechanism, 6-laser radar sensor, 7-movable connecting slot, 8-bolt, 9-PLC controller, 10-frequency converter. Detailed Implementation

[0051] To enable those skilled in the art to fully understand the technical solutions of the present invention, the present invention will be further described below in conjunction with embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0052] Example 1

[0053] See Figures 1-3 This embodiment discloses a tobacco leaf harvesting device, including a frame 1, a harvesting mechanism, a plant straightener 2, a guiding and separating mechanism 3, a lidar sensor assembly, and a control system; the harvesting mechanism, the plant straightener 2, and the lidar sensor assembly are all mounted on the frame 1; the plant straightener 2 is used to straighten the tobacco plants and guide them into the harvesting mechanism; the guiding and separating mechanism 3 is mounted on the harvesting mechanism to prevent the tobacco plants from shaking during harvesting and to separate tobacco leaves that do not need to be harvested.

[0054] See Figures 1-3The frame 1 is generally rectangular in shape and includes multiple U-shaped structural steels with the same cross-sectional shape, which are connected by welding.

[0055] See Figures 1-6 The harvesting mechanism includes two harvesting blades 4 arranged opposite each other for harvesting tobacco leaves, and two adjustment modules 5 for driving the harvesting blades 4 to adjust their harvesting height and angle. The adjustment modules 5 are arranged one-to-one with the harvesting blades 4. The harvesting blades 4 include a blade base 401 and harvesting blades 402 rotatably mounted on the blade base 401. Each adjustment module 5 includes two power components respectively arranged at the front and rear ends of the frame 1. Each power component includes a screw rod 501 rotatably mounted on the frame 1, a lifting platform 502 mounted on and connected to the screw rod 501, and a drive motor 503 for driving the screw rod 501 to rotate. The two lifting platforms 502 in the adjustment module 5 are movably connected to the front and rear ends of the blade base 401 respectively. The laser radar sensor assembly and the drive motor 503 are connected to the control system.

[0056] The harvesting platform 4 in this embodiment also includes a harvesting motor for driving the harvesting blades 402 to rotate. There are four power components in this embodiment, and the lifting platform 502 is vertically slidably mounted on the frame 1.

[0057] See Figures 1-6 The harvesting blade 402 is made of plastic material, and the blade edges 4021 on the left and right sides of the harvesting blade 402 are sinusoidal curves. When the blade edge 4021 of one harvesting blade 402 is raised, the corresponding position of the other harvesting blade 402 is a groove, that is, the two harvesting blades 402 can mesh with each other, which can improve the harvesting effect.

[0058] See Figures 1-4 The guiding and separating mechanism 3 includes two guiding and separating plates 301, which are correspondingly arranged with the harvesting cutter table 4. The guiding and separating plates 301 are fixedly installed on the cutter base 401. In the above structure, the two guiding and separating plates 301 are located on both sides of the axis of symmetry along the travel direction of the frame 1. The two guiding and separating plates 301 can restrict the left and right swaying of the tobacco leaves and divide the upper and lower space into a non-harvesting area and a harvesting area. The space above the guiding and separating plates 301 is the non-harvesting area, and the space below the guiding and separating plates 301 is the harvesting area, so that when harvesting the target part of the tobacco leaves, other parts of the tobacco leaves will not be damaged. The guiding and separating plates 301 and the harvesting cutter 402 move up, down and rotate synchronously. When the harvesting height changes, the tobacco leaves in the required harvesting range can still pass smoothly through the guiding and separating plates 301 and be harvested by the harvesting cutter 402, ensuring the harvesting accuracy.

[0059] See Figures 1-4 The separating guide plate includes a triangular guide frame 3011 at the front end and a flat plate 3012 at the rear end; the flat plate 3012 is connected to the cutter base 401 by a metal cylinder. The triangular guide frame 3011 guides the tobacco plants into the space between the harvesting cutters 402, while the flat plate 3012 acts as a separator and restricts the movement of the tobacco plants.

[0060] See Figures 1-3 The tobacco plant lifter 2 includes two lifting plates 201 disposed at the front end of the frame 1, with a funnel-shaped guide groove formed between the two lifting plates 201. The two lifting plates 201 are respectively located on both sides of the axis of symmetry along the travel direction of the frame 1, which is used to ensure that the tobacco plants smoothly enter the working space of the two harvesting blades 402 and avoid the harvesting device from pushing over or breaking the tobacco plants.

[0061] See Figures 1-3 The supporting plate 201 is triangular in shape, with the angle between the two metal cylinders at its head being 30 degrees, and a triangular steel plate welded to its middle.

[0062] See Figures 5-6 The front and rear ends of the tool base 401 are provided with bearing supports 403, and the picking tool 402 is mounted on the bearing supports 403 through bearings.

[0063] See Figures 1-3 The power assembly also includes a reducer 504, a transmission half-shaft 505, and a bevel gear transmission mechanism 506. The transmission half-shaft 505 is a universal joint type transmission shaft. The output end of the drive motor 503 is connected to the reducer 504 via a key. The output end of the reducer 504 is connected to one end of the transmission half-shaft 505. The other end of the transmission half-shaft 505 is connected to the driving bevel gear in the bevel gear transmission mechanism 506. The upper end of the helical rod 501 is connected to the driven bevel gear in the bevel gear transmission mechanism 506.

[0064] See Figures 1-3 The lidar sensor assembly includes multiple lidar sensors 6, which are respectively mounted on the upper middle part of the front end of the frame 1 and on the lifting platform 502. By using multiple lidar sensors 6, it is easy to accurately collect data on tobacco plants. The lidar sensors 6 are also used to collect the height of both ends of the harvesting table 4, and these lidar sensors 6 are connected to the control system.

[0065] The lidar sensor 6 is a TF02-Pro lidar sensor, and there are a total of 5 of them.

[0066] See Figures 4-6The tool base 401 has movable connecting grooves 7 at both its front and rear ends, and the lifting platform 502 is equipped with bolts 8, which are movably connected to the movable connecting grooves 7. Through this structure, the tool base 401 and the lifting platform 502 are movably connected. The vertical movement of the lifting platform 502 allows for adjustment of the height and angle of the tool base 401, ultimately achieving adjustment of the harvesting height and angle of the harvesting platform 4.

[0067] See Figures 1-6 The working principle of the above-mentioned tobacco leaf harvesting device is as follows:

[0068] When the tobacco harvesting device is harvesting tobacco leaves in the tobacco field, if the height of the tobacco plants in the same harvesting row is different, the lidar sensor component located at the top of the frame 1 collects data such as the distance and geometry of the tobacco plant stalks in front of the frame 1 to the lidar sensor component. After filtering the collected data, the height data of the tobacco leaves is obtained and sent to the control system that controls the lifting and lowering of the front and rear ends of the harvesting cutter table 4. The control system processes the received height data and sends the data to the drive motor 5 that drives the lifting and lowering of the front and rear ends of the harvesting cutter table 4. 03. Sending an instruction containing the required harvesting height information drives the motor 503 to output power, causing the screw rod 501 to rotate, changing the height of the front and rear ends of the harvesting table 4 and the angle of the harvesting table 4 relative to the ground, so that the harvesting mechanism can more accurately harvest the tobacco leaves from the desired parts of each tobacco plant, while reducing damage to tobacco leaves in parts that do not need to be harvested, greatly enhancing the automation level and applicability of the tobacco harvesting mechanism. During harvesting, the harvesting blade 402 rotates on the blade base 401, and the tobacco leaves are knocked down by the rotating harvesting blade 402.

[0069] Example 2

[0070] See Figures 1-6 This embodiment discloses an adaptive control method for the harvesting height and angle of the tobacco leaf harvesting device as described in Embodiment 1, comprising the following steps:

[0071] (1) Data acquisition: The lidar sensor assembly collects the height data of the tobacco leaves and the height data of the front and rear ends of the current harvesting table 4 in real time;

[0072] (2) Data processing: The data collected by the lidar sensor components is transmitted to the control system for processing;

[0073] (3) Control system calculation: The control system calculates the required harvesting height and angle based on the height data of the tobacco leaves and the height data of the front and rear ends of the current harvesting table 4.

[0074] (4) Adjustment of harvesting cutter 402: The control system controls four drive motors 503. The drive motors 503 output power to drive the screw rod 501 to rotate, which drives the lifting platform 502 to rise or fall, thereby realizing the adjustment of the height and angle of the cutter base 401, and thus realizing the adjustment of the height and angle of the harvesting cutter 402, until the harvesting cutter 402 reaches the required harvesting height and angle.

[0075] (5) Movement of the picking device: The control system controls the movement of the picking device so that the picking device can accurately contact the tobacco leaves.

[0076] (6) Harvesting operation: The harvesting knife 402 harvests the tobacco leaves according to the calculated harvesting height and angle;

[0077] (7) Feedback adjustment: The control system dynamically adjusts the harvesting height and angle of the harvesting blade 402 according to the actual situation during the harvesting process;

[0078] (8) Repeat operation: Repeat steps (2)-(7) to achieve adaptive control of the picking tool 402.

[0079] The adaptive control method is based on the tobacco leaf growth status detected by the lidar sensor 6 and the position information of both ends of the harvesting knife 402. The control system calculates and adjusts the harvesting height and angle of the harvesting knife 402 in real time to achieve automated tobacco leaf harvesting.

[0080] By inputting the height of the lidar sensor 6 above the ground and the vertical distance from the top of the tobacco plant to the lidar sensor 6 (positive for high, negative for low), the total height of the tobacco plant is calculated. The distances from one-third and two-thirds of the total height of the tobacco plant to the lidar sensor 6 in the vertical direction are then calculated. The vertical position of the front end of the harvesting blade 402 is set to equal two-thirds of the total height of the tobacco plant, and the vertical position of the rear end of the harvesting blade 402 is set to equal one-third of the total height of the tobacco plant, thus achieving height and angle self-adaptation. The height data of the tobacco leaf is the total height of the tobacco plant.

[0081] During the tobacco harvesting process, the tobacco leaves on the tobacco plant are divided into three sections: upper tobacco leaves, middle tobacco leaves, and lower tobacco leaves. The area between one-third and two-thirds of the total height of the tobacco plant is the middle tobacco leaf area.

[0082] See Figures 1-3 and Figure 7The control system includes a PLC controller 9. The PLC controller 9 controls the height and angle of the harvesting blade 402 through an adaptive PID control strategy, which is applied to the PID controller. The PID controller is characterized by convenient operation, good robustness, and wide applicability. The PID controller includes a proportional unit, an integral unit, and a derivative unit. The basic working principle of the PID controller is to perform proportional, integral, and derivative operations on the feedback error signal to obtain the driving voltage signal. Its Laplace mathematical transfer model formula is as follows:

[0083]

[0084] Where U(s) is the driving voltage signal, E(s) is the feedback error signal, and K p K i K d Here are the system control parameters, where,

[0085] K p The proportional gain is the coefficient that changes the system gain. As the proportional gain increases, the amplitude of the system response signal becomes larger, but at the same time, the system stability gradually deteriorates. As the proportional gain becomes larger and larger, the overshoot of the system becomes larger and larger, and the changes become more and more drastic, until it becomes a divergent system. However, for a stable system, increasing the proportional gain will shorten the signal response time and increase the response speed.

[0086] K d The coefficient is the derivative. Although proportional control can also shorten the system response time, it does so by amplifying the error, which leads to poor stability and cannot suppress the error in advance. Derivative control solves this problem and also avoids overshoot of the controlled variable.

[0087] K i The integral coefficient affects the stability of the system. As the integral coefficient increases, the system response time shortens and it can reach the stable value more quickly. However, the oscillation amplitude of the system increases, and the system stability decreases.

[0088] The control system in this embodiment adopts a discrete control system. First, the continuous PID model is written as a discrete full-quantity PID control model, and its difference model structure is shown in the following equation:

[0089] U(k)=K p e(k)+K i ∑e(k)+K d [e(k)-e(k-1)]

[0090] e(k) = r(k) - y(k)

[0091] In the formula, U(k) is the driving voltage signal, and K p K i K d These are the proportional coefficient, integral coefficient, and derivative coefficient, respectively; e(k) is the error signal; r(k) is the reference signal; and y(k) is the output signal.

[0092] Since the error integral in the above full-scale PID model is accumulated, integral control is rarely used, and long-term accumulation calculations can easily lead to computer memory overflow. Therefore, this implementation adopts an incremental PID control model, the structure of which is shown in the following equation:

[0093] Δu(k)=k1e(k)+k2Δe(k)+k3Δ 2 e(k)

[0094] Δu(k) is the increment of the driving signal, k1, k2, and k3 are the integral coefficient, proportional coefficient, and derivative coefficient, respectively, and e(k), Δe(k), and Δ 2 e(k) represents the error, the first increment of the error, and the second increment of the error, respectively, and is calculated using the following formula:

[0095] e(k) = r(k) - y(k)

[0096] Δe(k)=e(k)-e(k-1)

[0097] Δ 2 e(k)=Δe(k)-Δe(k-1)=e(k)-2e(k-1)+(k-2)

[0098] Where r(k) is the reference signal and y(k) is the output signal.

[0099] The formula for calculating the driving signal at the current moment is as follows:

[0100] u(k)=u(k-1)+Δu(k).

[0101] See Figures 1-3 The harvesting mechanism also includes a frequency converter 10, and the PLC controller 9 is connected to the drive motor 503 through the frequency converter 10. By setting the frequency converter 10, the drive motor 503 can be controlled.

[0102] See Figures 1-3 The frequency converter 10 is an ATV320 frequency converter. The PLC controller 9 is a PLCS7-1200 controller.

[0103] See Figures 1-3 and Figure 8 The PLC controller 9 and the frequency converter 10 communicate via the CAN protocol.

[0104] The microcontroller unit (MCU) processes the data from the CAN controller. The CAN controller and the CAN transceiver transmit data by sending and receiving specific electrical signals. Different CAN nodes transmit data differentially through the CAN bus. CANHigh (high-order data line) and CANLow (low-order data line) together form a set of differential signal lines. Differential data transmission can effectively reduce the interference of external electromagnetic noise on the signal, especially common-mode noise. When the bus is interfered with, both buses will be affected simultaneously, but their differential voltage will not be affected, ensuring the stability of data transmission.

[0105] By adjusting the control parameters of the PID controller, the output signal can track the input signal, and finally the three parameter setpoints of the PID are obtained.

[0106] By setting an integral limit, the maximum vertical displacement of the left and right ends of the harvesting blade 4 is limited. By setting an integral separation, when the harvesting device resets its movement distance midway through harvesting, the control parameters of the PID controller from the previous control cycle are used for this calculation, avoiding control system disorder that could cause the displacement of the two ends of the harvesting blade 402 to become uncontrollable. The height data of the tobacco leaves and the height of the two ends of the harvesting blade 402 in each control cycle are obtained by the laser radar sensor 6, and the tracking error of that cycle is calculated. Combined with the error increment and based on the three control parameters of the PID controller, the output signal of the control system is adjusted, thereby controlling the harvesting height and angle of the harvesting blade 402.

[0107] The above are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above content. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. An adaptive control method for the harvesting height and angle of a tobacco leaf harvesting device, characterized in that, The tobacco leaf harvesting device includes a frame, a harvesting mechanism, a lidar sensor assembly, and a control system. The harvesting mechanism and lidar sensor assembly are both mounted on the frame. The harvesting mechanism includes two oppositely arranged harvesting blades for harvesting tobacco leaves and two adjustment modules for driving the harvesting blades to adjust their harvesting height and angle. Each adjustment module corresponds to one of the harvesting blades. Each harvesting blade includes a blade base and harvesting blades rotatably mounted on the blade base. Each adjustment module includes two power components respectively located at the front and rear ends of the frame. Each power component includes a rotatably mounted screw rod on the frame, a lifting platform mounted on and connected to the screw rod, and a drive motor for driving the screw rod to rotate. The two lifting platforms in each adjustment module are movably connected to the front and rear ends of the blade base. The lidar sensor assembly and drive motor are connected to the control system. The adaptive control method includes the following steps: (1) Data acquisition: The lidar sensor assembly acquires the height data of the tobacco leaves and the current height data of the harvesting table in real time; (2) Data processing: The data collected by the lidar sensor components is transmitted to the control system for processing; (3) Control system calculation: The control system calculates the required harvesting height and angle based on the height data of the tobacco leaves and the current height data of the harvesting table; (4) Harvesting knife adjustment: The control system controls four drive motors, which output power to drive the screw rod to rotate, thereby driving each lifting platform to rise or fall, so as to adjust the height and angle of the knife base, and thus adjust the height and angle of the harvesting knife until the harvesting knife reaches the required harvesting height and angle. (5) Movement of the picking device: The control system controls the movement of the picking device so that the picking device can accurately contact the tobacco leaves; (6) Harvesting operation: The harvesting knife harvests the tobacco leaves according to the calculated harvesting height and angle; (7) Feedback adjustment: The control system dynamically adjusts the harvesting height and angle of the harvesting blades according to the actual situation during the harvesting process; (8) Repeat the operation: Repeat steps (2)-(7) to achieve adaptive control of the harvesting knife; The tobacco leaf picking device also includes a plant straightener and a guiding and separating mechanism; the plant straightener is located at the front end of the frame; the plant straightener is used to straighten the tobacco plants and guide them into the picking mechanism; the guiding and separating mechanism is located on the picking mechanism to prevent the tobacco plants from shaking during picking and to separate tobacco leaves that do not need to be picked. The guiding and separating mechanism includes two guiding and separating plates, which are respectively arranged in one-to-one correspondence with the harvesting cutter table, and the guiding and separating plates are fixedly installed on the cutter base; The guide partition plate includes a triangular guide frame at the front end and a flat plate at the rear end; the flat plate is connected to the tool base by a metal cylinder; The lidar sensor assembly includes multiple lidar sensors, which are respectively installed on the upper middle part of the front end of the frame and on the lifting platform. The control system includes a PLC controller. The PLC controller controls the height and angle of the harvesting blade through an adaptive PID control strategy. The adaptive PID control strategy is applied to the PID controller, which includes a proportional unit, an integral unit, and a derivative unit. The harvesting mechanism also includes a frequency converter, and the PLC controller is connected to the drive motor through the frequency converter; By setting an integral limit, the maximum vertical displacement of the left and right ends of the harvesting blade is limited; by setting integral separation, when the harvesting device resets its movement distance midway through harvesting, the control parameters of the PID controller from the previous control cycle are used for this calculation; by acquiring the height data of the tobacco leaves and the height of both ends of the harvesting blade in each control cycle through the lidar sensor, the tracking error of that cycle is calculated, and combined with the error increment and based on the three control parameters of the PID controller, the output signal of the control system is adjusted to control the harvesting height and angle of the harvesting blade; the three control parameters are the proportional coefficient, integral coefficient, and derivative coefficient.

2. The adaptive control method for the harvesting height and angle of a tobacco leaf harvesting device according to claim 1, characterized in that, The harvesting knife is made of plastic, and the blade edges on both sides of the harvesting knife are sinusoidal curves.

3. The adaptive control method for the harvesting height and angle of a tobacco leaf harvesting device according to claim 1, characterized in that, The lifting device includes two lifting plates disposed at the front end of the frame, with a funnel-shaped guide groove formed between the two lifting plates.

4. The adaptive control method for the harvesting height and angle of a tobacco leaf harvesting device according to claim 1, characterized in that, The tool base is provided with movable connecting grooves at both ends, and the lifting platform is provided with bolts, which are movably connected to the movable connecting grooves.

5. The adaptive control method for the harvesting height and angle of a tobacco leaf harvesting device according to claim 1, characterized in that, The PLC controller and the frequency converter communicate via the CAN protocol.

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