A method and apparatus for adjusting a combine harvester sieve plate

Abstract

This invention provides a method and apparatus for adjusting the screen plates of a combine harvester. The method includes: S1, calibrating the screen plate motor to obtain the correspondence between the upper and lower limit ranges of the screen plate opening and the upper and lower limit position potential count value ranges of the screen plate motor; S2, acquiring the current value of the screen plate motor potentiometer, the actual expected value of the screen plate opening, and the screen plate motor control strategy; S3, converting the actual expected value of the screen plate opening into the expected value of the adjusting motor potentiometer based on the correspondence between the upper and lower limit ranges of the screen plate opening and the upper and lower limit position potential count value ranges of the screen plate motor; S4, calculating the error value between the expected value of the adjusting motor potentiometer and the current value of the screen plate motor potentiometer in real time; S5, controlling the screen plate motor according to the error value and the screen plate motor control strategy to increase or decrease the screen plate opening. By establishing the correspondence between the screen plate opening and the potentiometer value, the initial configuration is simplified, reducing the cost of manual intervention.

Description

Technical Field

[0001] This invention relates to the field of combine harvester screen adjustment technology, and in particular to a method and apparatus for adjusting combine harvester screens. Background Technology

[0002] In the field of agricultural machinery engineering, especially in the design and manufacture of grain combine harvesters, adjusting the sieve opening is crucial for improving screening efficiency and reducing losses. With the increasing level of agricultural mechanization, the requirements for automation in the grain harvesting process are also rising. Traditional methods of adjusting the sieve opening typically rely on manual operation or simple mechanical devices, which not only increases the difficulty of operation but also makes precise control difficult, thus affecting screening efficiency and crop quality.

[0003] In existing solutions, some advanced harvesting equipment has incorporated electronic control systems for adjusting the screen opening. These systems collect environmental information (such as material flow rate and humidity) through sensors installed on the harvester, and then use pre-set algorithms to automatically adjust the screen opening. However, the implementation of such systems mostly relies on complex electronic control systems, which are costly and difficult to maintain.

[0004] Although existing technologies have improved the accuracy and flexibility of sieve opening adjustment to some extent, they still have significant shortcomings:

[0005] 1. High cost: The cost of the electronic control system and its supporting components (such as electric actuators) is high, which is not conducive to large-scale promotion.

[0006] 2. Reliability issues: Due to the harsh working environment (dust, screen box swaying, etc.), the reliability and stability of the electrical control system face challenges.

[0007] 3. Screen plate control issues: For ordinary users, understanding and operating the control system is somewhat difficult. The screen plate adjustment motor needs to swing back and forth synchronously with the screen box. Under this condition, the traditional PID control method is prone to overshoot in the screen plate adjustment effect, making debugging difficult. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to provide a method and device for adjusting the screen of a combine harvester, which addresses the shortcomings of the prior art.

[0009] The technical solution of this invention to solve the above-mentioned technical problems is as follows: A method for adjusting the screen of a combine harvester, comprising: S1, calibrating the screen motor to obtain the correspondence between the upper and lower limit ranges of the screen opening and the upper and lower limit position potential count value ranges of the screen motor; S2, obtaining the current value of the screen motor potentiometer, the actual expected value of the screen opening, and the screen motor control strategy; S3, converting the actual expected value of the screen opening into the expected value of the adjusting motor potentiometer according to the correspondence between the upper and lower limit ranges of the screen opening and the upper and lower limit position potential count value ranges of the screen motor; S4, calculating the error value between the expected value of the adjusting motor potentiometer and the current value of the screen motor potentiometer in real time; S5, controlling the screen motor according to the error value and the screen motor control strategy to increase or decrease the screen opening.

[0010] The beneficial effects of adopting the technical solution of this invention are as follows: After obtaining the actual expected value of the screen opening, it is converted into the expected value of the potentiometer of the screen adjusting motor. The error between the expected value and the current value of the motor potentiometer is calculated in real time, and this potentiometer error will be used as the input variable for the screen motor positioning control. The method of converting the expected value into the potentiometer expected value achieves accurate conversion between different physical quantities. The real-time error calculation method improves control accuracy. Through the correspondence between the screen opening and the potentiometer value, the system initialization configuration is simplified, and the cost of manual intervention is reduced.

[0011] Furthermore, the control strategy for the screen plate motor is: segmented PWM signal control, PID closed-loop control, or fuzzy control.

[0012] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: The segmented PWM signal control method for the screen motor solves the overshoot problem caused by traditional PID motor control, reducing debugging difficulty. The segmented PWM signal output positioning control method ensures that the screen motor reduces overshoot during positioning control. As an alternative, PID closed-loop control optimizes proportional, integral, and derivative parameters, resulting in a smoother dynamic response. As an alternative, fuzzy control is robust to nonlinear and time-varying systems and does not require a precise mathematical model.

[0013] Further, step S1 includes: S11, pressing the screen motor decrease button to adjust the screen to the minimum opening position, pressing the "calibrate" button on the screen motor calibration interface, and recording and saving the current potentiometer value of the screen motor; S12, determining whether the HMI indicates successful calibration; S13, when the HMI indicates successful calibration, pressing the screen motor increase button to adjust the screen to the maximum opening position, pressing the "calibrate" button on the screen motor calibration interface, and recording and saving the current potentiometer value of the screen motor; S14, determining whether the HMI indicates successful calibration; S15, when the HMI indicates successful calibration, the calibration ends.

[0014] The beneficial effects of adopting the above-mentioned further technical solution are as follows: Through the above steps, the correspondence between the upper and lower limit ranges of the screen opening and the upper and lower limit position potential count value ranges of the screen motor can be obtained. The design of the automated calibration process realizes the intelligent and automated calibration of the screen motor. By calibrating the correspondence between the screen opening and the potentiometer value through the HMI interface, the system initialization configuration is simplified, and the cost of manual intervention is reduced.

[0015] Further, step S3 includes: S31, obtaining the current value of the sieve motor potentiometer; S32, converting the current value of the sieve motor potentiometer into the actual value of the sieve opening, and displaying it on the HMI.

[0016] The beneficial effect of adopting the above-mentioned further technical solution is that the current value of the potentiometer is converted into the actual value of the sieve opening in real time for HMI display, thereby achieving the purpose of human-computer interaction.

[0017] Furthermore, when the screen motor control strategy is segmented PWM signal control, step S2 includes: when the actual expected value of the screen opening input by the HMI is obtained, the system is initialized to prepare for motor control, and a 0% PWM control signal is output to the screen motor to keep the screen motor stationary.

[0018] The beneficial effects of adopting the above-mentioned further technical solution are as follows: When the "target value transmission" button is triggered from the HMI terminal, the control device will immediately start the screen motor positioning control. The system is initialized in preparation for screen motor control. In the initial state, a 0% PWM control signal is output to the screen motor, keeping it stationary. The HMI sets the actual expected value of the screen opening and the transmission mechanism to ensure the accurate transmission of the target value.

[0019] Furthermore, when the screen motor control strategy is segmented PWM signal control, step S5 includes: S51, calculating the absolute value of the error; S52, determining whether the absolute value of the error is greater than 30; S53, when the absolute value of the error is greater than 30, determining the sign of the error; S54, when the error is greater than 0 and not less than 30, adjusting the duty cycle of the PWM output signal segmentally according to the magnitude of the error to control the screen motor to increase the screen opening; S55, when the error is less than 0 and not greater than -30, adjusting the duty cycle of the PWM output signal segmentally according to the magnitude of the error to control the screen motor to decrease the screen opening.

[0020] The beneficial effects of adopting the above-mentioned further technical solution are as follows: The error input of the control device is the potentiometer error. The error value is monitored in real time, and its absolute value Abs (error) is calculated. If Abs (error) > 30, the sign of the error value is further determined: if the error > 0 and the error ≥ 30, the screen opening increase control method is entered; if the error < 0 and the error ≤ -30, the screen opening decrease control method is entered. According to the magnitude of Abs (error), the duty cycle of the PWM output signal is adjusted in segments. The positioning accuracy of the screen motor can be controlled within ±30Mv of the potentiometer error monitored by the potentiometer. The development of the error correction algorithm further improves the calibration accuracy and stability. The real-time error calculation method improves the control accuracy. During the adjustment process, the error direction (positive / negative) is monitored in real time, and the control logic is dynamically switched to increase or decrease, avoiding overshoot and improving the adaptiveness of the error direction.

[0021] Further, when the screen motor control strategy is segmented PWM signal control, step S54 includes: if the absolute value of the error is greater than 400, the PWM output is +100% control signal; if the absolute value of the error is greater than 200 and not greater than 400, the PWM output is +65% control signal; if the absolute value of the error is greater than 100 and not greater than 200, the PWM output is +40% control signal; if the absolute value of the error is greater than 30 and not greater than 100, the PWM output is +30% control signal; if the absolute value of the error is not greater than 30, the PWM output is... M outputs a 0% control signal, ending the process; Step S55 includes: if the absolute value of the error is greater than 400, PWM outputs a -100% control signal; if the absolute value of the error is greater than 200 and not greater than 400, PWM outputs a -65% control signal; if the absolute value of the error is greater than 100 and not greater than 200, PWM outputs a -40% control signal; if the absolute value of the error is greater than 30 and not greater than 100, PWM outputs a -30% control signal; if the absolute value of the error is not greater than 30, PWM outputs a 0% control signal, ending the process.

[0022] The beneficial effects of adopting the above-mentioned further technical solution are as follows: The segmented PWM signal control method for the screen motor solves the overshoot problem caused by traditional PID motor control, reducing debugging difficulty. The segmented PWM signal output positioning control method ensures that the screen motor reduces overshoot during positioning control. The duty cycle of the PWM output signal is adjusted segmentally according to the magnitude of the Abs (error). Through segmented PWM control, the positioning accuracy of the screen motor can be controlled within ±30Mv of the potentiometer error, meeting the accuracy requirements for screen opening adjustment. Error compensation algorithms and system self-calibration functions ensure the long-term stability and control accuracy of the system. The PWM duty cycle is set segmentally according to the absolute value of the error (±100% / ±65% / ±40% / ±30%), achieving dynamic switching between coarse and fine adjustment, balancing adjustment speed and accuracy.

[0023] Furthermore, when the screen motor control strategy is segmented PWM signal control, in step S54, if the error value is not greater than -30, step S54 is immediately exited and step S52 is executed; in step S55, if the error value is not less than 30, step S55 is immediately exited and step S52 is executed.

[0024] The beneficial effects of adopting the above-mentioned further technical solution are as follows: During the positioning control process in step 54, when "error ≤ -30" is monitored, step 54 is immediately exited and the process proceeds to step 42; during the positioning control process in step 55, when "error ≥ 30" is monitored, step 55 is immediately exited and the process proceeds to step 52. This allows the positioning accuracy of the screen motor to be controlled within ±30 Mv of the potentiometer error, which is the monitored quantity. When the error direction changes abruptly (error ≤ -30 or ≥ 30), the current control process is immediately interrupted and the error is reassessed to prevent system oscillation.

[0025] Furthermore, the present invention also provides a combine harvester screen adjustment device for performing a combine harvester screen adjustment method as described in any of the above claims. The combine harvester screen adjustment device includes: a screen motor, a screen adjustment linkage, a screen adjustment crankshaft, a screen, an HMI, a vehicle controller, and a drive module. The screen motor is connected to the screen adjustment linkage, the screen adjustment linkage has a groove, the screen adjustment crankshaft is installed in the groove on the screen adjustment linkage, the screen is connected to the screen adjustment crankshaft, the vehicle controller is connected to the HMI, the drive module, and the screen motor, and the drive module is connected to the screen motor.

[0026] The beneficial effects of adopting the technical solution of this invention are as follows: the screen plate adjusting linkage moves parallel under the axial drive of the motor output shaft. Through the groove structure of the screen plate adjusting linkage, it drives the screen plate adjusting crankshaft to rotate, thereby realizing the angle adjustment of the screen plates and thus the opening adjustment between adjacent screen plates. By driving the screen plate adjusting linkage with the motor, the axial motion of the motor is converted into the rotation angle adjustment of the screen plates. The mechanical structure is compact, the transmission efficiency is high, and there is no need for complex gear sets. By utilizing the groove structure of the screen plate adjusting linkage in cooperation with the crankshaft, the precise conversion from linear motion to rotational motion is achieved, meeting the continuous adjustment requirements of the screen plate opening.

[0027] Furthermore, the screen motor is a DC brushless geared motor, a stepper motor, or a servo motor; the screen motor is connected to a motor output shaft, the motor output shaft is connected to a motor transition link, the motor transition link is connected to the screen adjustment link by bolts, and a manual adjustment knob is installed at the tail end of the screen motor; the HMI is connected to the vehicle controller via a CAN bus, the vehicle controller is connected to the drive module via CAN communication, and the drive module is connected to the screen motor via a hard-wired signal; when the screen motor is a DC brushless geared motor, the DC brushless geared motor has a built-in potentiometer, and the potentiometer is connected to the vehicle controller via a hard-wired signal; when the screen motor is a servo motor, the servo motor is connected to an encoder.

[0028] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: The use of a brushless geared motor as the drive component for screen adjustment significantly reduces costs compared to the electric control system using an electric actuator. The use of a DC brushless geared motor offers greater adaptability to the working environment compared to an electric actuator. The manual adjustment knob at the end of the DC brushless geared motor retains the basic function of manual adjustment. The manual adjustment knob at the end of the screen motor retains a mechanical redundancy design, ensuring that the screen opening can still be adjusted manually in the event of a screen motor failure or power outage, thus improving system reliability. The potentiometer signal built into the DC brushless geared motor is connected to the vehicle controller via a hard-wired signal, providing feedback on the current position of the DC brushless geared motor to the vehicle controller as a potentiometer signal. Utilizing the real-time position signal feedback from the built-in potentiometer of the screen motor forms a closed-loop control, ensuring the accuracy and stability of the screen opening adjustment. The DC brushless geared motor drives a linkage mechanism, converting the axial motion of the motor into the rotation angle adjustment of the screen, resulting in a compact mechanical structure, high transmission efficiency, and eliminating the need for complex gear sets. By utilizing the grooved structure of the screen adjustment linkage in conjunction with the crankshaft, precise conversion from linear motion to rotary motion is achieved, meeting the requirement for continuous adjustment of the screen opening. A hierarchical control architecture of HMI → vehicle controller → drive module → motor is adopted, with signal transmission via CAN bus. The system boasts strong scalability and is easy to integrate into the vehicle control system. As an alternative, a stepper motor + open-loop control is used, eliminating the need for potentiometer feedback and achieving position control through pulse counting, resulting in lower costs. As yet another alternative, a servo motor + encoder feedback is employed. The encoder's resolution is significantly higher than that of a potentiometer, making it suitable for scenarios requiring higher precision.

[0029] The advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0030] Figure 1 This is one of the schematic flowcharts of a combine harvester screen adjustment method provided in an embodiment of the present invention;

[0031] Figure 2 This is a second schematic flowchart of a combine harvester screen adjustment method provided in an embodiment of the present invention.

[0032] Figure 3 The third illustrative flowchart of the combine harvester screen adjustment method provided in the embodiments of the present invention;

[0033] Figure 4 The fourth schematic flowchart of the combine harvester screen adjustment method provided in the embodiments of the present invention;

[0034] Figure 5 This is one of the structural schematic diagrams of the combine harvester screen adjustment device provided in an embodiment of the present invention;

[0035] Figure 6 This is the second schematic diagram of the structure of the combine harvester screen adjustment device provided in the embodiment of the present invention.

[0036] Reference numerals: 101, Screen adjustment crankshaft; 102, Screen adjustment connecting rod; 103, Screen; 104, Bolt; 105, Motor transition connecting rod; 106, Motor output shaft; 107, Screen motor; 108, Manual adjustment knob; 109, HMI; 110, Vehicle controller; 111, Drive module. Detailed Implementation

[0037] The principles and features of the present invention are described below with reference to the accompanying drawings. The embodiments described are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0038] like Figure 1 As shown, this embodiment of the invention provides a method for adjusting the screen of a combine harvester, including: S1, calibrating the screen motor to obtain the correspondence between the upper and lower limit ranges of the screen opening and the upper and lower limit position potential count value ranges of the screen motor; S2, acquiring the current value of the screen motor potentiometer, the actual expected value of the screen opening, and the screen motor control strategy; S3, converting the actual expected value of the screen opening into the expected value of the adjusting motor potentiometer based on the correspondence between the upper and lower limit ranges of the screen opening and the upper and lower limit position potential count value ranges of the screen motor; S4, calculating the error value between the expected value of the adjusting motor potentiometer and the current value of the screen motor potentiometer in real time; S5, controlling the screen motor according to the error value and the screen motor control strategy to increase or decrease the screen opening.

[0039] The beneficial effects of adopting the technical solution of this invention are as follows: After obtaining the actual expected value of the screen opening, it is converted into the expected value of the potentiometer of the screen adjusting motor. The error between the expected value and the current value of the motor potentiometer is calculated in real time, and this potentiometer error will be used as the input variable for the screen motor positioning control. The method of converting the expected value into the potentiometer expected value achieves accurate conversion between different physical quantities. The real-time error calculation method improves control accuracy. Through the correspondence between the screen opening and the potentiometer value, the system initialization configuration is simplified, and the cost of manual intervention is reduced.

[0040] Furthermore, the control strategy for the screen plate motor is: segmented PWM signal control, PID closed-loop control, or fuzzy control.

[0041] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: The segmented PWM signal control method for the screen motor solves the overshoot problem caused by traditional PID motor control, reducing debugging difficulty. The segmented PWM signal output positioning control method ensures that the screen motor reduces overshoot during positioning control. As an alternative, PID closed-loop control optimizes proportional, integral, and derivative parameters, resulting in a smoother dynamic response. As an alternative, fuzzy control is robust to nonlinear and time-varying systems and does not require a precise mathematical model.

[0042] Control Algorithm Alternatives

[0043] Option 1: PID closed-loop control. Advantages: Smoother dynamic response through optimization of proportional, integral, and derivative parameters.

[0044] Option 2: Fuzzy control. Advantages: Strong robustness to nonlinear and time-varying systems, no need for precise mathematical models.

[0045] Further, step S1 includes: S11, pressing the screen motor decrease button to adjust the screen to the minimum opening position, pressing the "calibrate" button on the screen motor calibration interface, and recording and saving the current potentiometer value of the screen motor; S12, determining whether the HMI indicates successful calibration; S13, when the HMI indicates successful calibration, pressing the screen motor increase button to adjust the screen to the maximum opening position, pressing the "calibrate" button on the screen motor calibration interface, and recording and saving the current potentiometer value of the screen motor; S14, determining whether the HMI indicates successful calibration; S15, when the HMI indicates successful calibration, the calibration ends.

[0046] The beneficial effects of adopting the above-mentioned further technical solution are as follows: Through the above steps, the correspondence between the upper and lower limit ranges of the screen opening and the upper and lower limit position potential count value ranges of the screen motor can be obtained. The design of the automated calibration process realizes the intelligent and automated calibration of the screen motor. By calibrating the correspondence between the screen opening and the potentiometer value through the HMI interface, the system initialization configuration is simplified, and the cost of manual intervention is reduced.

[0047] Further, step S3 includes: S31, obtaining the current value of the sieve motor potentiometer; S32, converting the current value of the sieve motor potentiometer into the actual value of the sieve opening, and displaying it on the HMI.

[0048] The beneficial effect of adopting the above-mentioned further technical solution is that the current value of the potentiometer is converted into the actual value of the sieve opening in real time for HMI display, thereby achieving the purpose of human-computer interaction.

[0049] Furthermore, when the screen motor control strategy is segmented PWM signal control, step S2 includes: when the actual expected value of the screen opening input by the HMI is obtained, the system is initialized to prepare for motor control, and a 0% PWM control signal is output to the screen motor to keep the screen motor stationary.

[0050] The beneficial effects of adopting the above-mentioned further technical solution are as follows: When the "target value transmission" button is triggered from the HMI terminal, the control device will immediately start the screen motor positioning control. The system is initialized in preparation for screen motor control. In the initial state, a 0% PWM control signal is output to the screen motor, keeping it stationary. The HMI sets the actual expected value of the screen opening and the transmission mechanism to ensure the accurate transmission of the target value.

[0051] Furthermore, when the screen motor control strategy is segmented PWM signal control, step S5 includes: S51, calculating the absolute value of the error; S52, determining whether the absolute value of the error is greater than 30; S53, when the absolute value of the error is greater than 30, determining the sign of the error; S54, when the error is greater than 0 and not less than 30, adjusting the duty cycle of the PWM output signal segmentally according to the magnitude of the error to control the screen motor to increase the screen opening; S55, when the error is less than 0 and not greater than -30, adjusting the duty cycle of the PWM output signal segmentally according to the magnitude of the error to control the screen motor to decrease the screen opening.

[0052] The beneficial effects of adopting the above-mentioned further technical solution are as follows: The error input of the control device is the potentiometer error. The error value is monitored in real time, and its absolute value Abs (error) is calculated. If Abs (error) > 30, the sign of the error value is further determined: if the error > 0 and the error ≥ 30, the screen opening increase control method is entered; if the error < 0 and the error ≤ -30, the screen opening decrease control method is entered. According to the magnitude of Abs (error), the duty cycle of the PWM output signal is adjusted in segments. The positioning accuracy of the screen motor can be controlled within ±30Mv of the potentiometer error monitored by the potentiometer. The development of the error correction algorithm further improves the calibration accuracy and stability. The real-time error calculation method improves the control accuracy. During the adjustment process, the error direction (positive / negative) is monitored in real time, and the control logic is dynamically switched to increase or decrease, avoiding overshoot and improving the adaptiveness of the error direction.

[0053] Further, when the screen motor control strategy is segmented PWM signal control, step S54 includes: if the absolute value of the error is greater than 400, the PWM output is +100% control signal; if the absolute value of the error is greater than 200 and not greater than 400, the PWM output is +65% control signal; if the absolute value of the error is greater than 100 and not greater than 200, the PWM output is +40% control signal; if the absolute value of the error is greater than 30 and not greater than 100, the PWM output is +30% control signal; if the absolute value of the error is not greater than 30, the PWM output is... M outputs a 0% control signal, ending the process; Step S55 includes: if the absolute value of the error is greater than 400, PWM outputs a -100% control signal; if the absolute value of the error is greater than 200 and not greater than 400, PWM outputs a -65% control signal; if the absolute value of the error is greater than 100 and not greater than 200, PWM outputs a -40% control signal; if the absolute value of the error is greater than 30 and not greater than 100, PWM outputs a -30% control signal; if the absolute value of the error is not greater than 30, PWM outputs a 0% control signal, ending the process.

[0054] The beneficial effects of adopting the above-mentioned further technical solution are as follows: The segmented PWM signal control method for the screen motor solves the overshoot problem caused by traditional PID motor control, reducing debugging difficulty. The segmented PWM signal output positioning control method ensures that the screen motor reduces overshoot during positioning control. The duty cycle of the PWM output signal is adjusted segmentally according to the magnitude of the Abs (error). Through segmented PWM control, the positioning accuracy of the screen motor can be controlled within ±30Mv of the potentiometer error, meeting the accuracy requirements for screen opening adjustment. Error compensation algorithms and system self-calibration functions ensure the long-term stability and control accuracy of the system. The PWM duty cycle is set segmentally according to the absolute value of the error (±100% / ±65% / ±40% / ±30%), achieving dynamic switching between coarse and fine adjustment, balancing adjustment speed and accuracy.

[0055] Furthermore, when the screen motor control strategy is segmented PWM signal control, in step S54, if the error value is not greater than -30, step S54 is immediately exited and step S52 is executed; in step S55, if the error value is not less than 30, step S55 is immediately exited and step S52 is executed.

[0056] The beneficial effects of adopting the above-mentioned further technical solution are as follows: During the positioning control process in step 54, when "error ≤ -30" is monitored, step 54 is immediately exited and the process proceeds to step 42; during the positioning control process in step 55, when "error ≥ 30" is monitored, step 55 is immediately exited and the process proceeds to step 52. This allows the positioning accuracy of the screen motor to be controlled within ±30 Mv of the potentiometer error, which is the monitored quantity. When the error direction changes abruptly (error ≤ -30 or ≥ 30), the current control process is immediately interrupted and the error is reassessed to prevent system oscillation.

[0057] Technical solution for controlling the motor of the sieve plate adjustment

[0058] 1. Calibration method for the sieve plate adjusting motor (sieve plate motor 107), such as... Figure 2 As shown:

[0059] Calibration begins. Step 1: Press the screen motor reduce button to adjust the screen to the minimum opening (5mm). On the screen motor calibration interface, press the "Calibrate" button to record and save the current potentiometer value of the screen motor.

[0060] Step 2: Determine if the HMI indicates successful calibration. If it indicates successful calibration, proceed to the next step; otherwise, repeat Step 1.

[0061] Step 3: Press the screen motor increase button to adjust the screen to the maximum opening (25mm). On the screen motor calibration interface, press the "calibrate" button to record and save the current potentiometer value of the screen motor.

[0062] Step 4: Determine if the HMI indicates successful calibration. If it indicates successful calibration, the calibration ends; otherwise, repeat step 3.

[0063] Step 5: Through the above four steps, the correspondence between the upper and lower limits (unit: mm) of the screen opening and the upper and lower limit position potential count values ​​(unit: mV) of the screen motor can be obtained. Using this correspondence K, the following two effects can be achieved:

[0064] ① The control system (control device) converts the current value of the potentiometer into the actual value of the screen opening in real time for HMI display, achieving human-machine interaction; ② The technical solution for transmitting the target value of the screen motor, such as... Figure 3As shown, after setting the actual expected value of the screen opening at the HMI terminal, when the "Target Value Send" button is pressed at the HMI terminal, under the system architecture of the technical solution (screen adjustment control system technical solution), the control system can obtain the actual expected value (unit: mm) input by the HMI and convert it into the expected value of the screen adjustment motor potentiometer. The control system will calculate the error between the expected value of the motor potentiometer and the current value of the motor potentiometer in real time. This potentiometer error will be used as the input variable for the positioning control of the screen adjustment motor.

[0065] like Figure 3 As shown, the process begins with: 1. Setting the HMI to the actual expected value of the sieve opening (actual expected value, unit mm, actual value range 5mm-25mm); 2. Determining whether the HMI has issued the actual expected value; 3. When the HMI has issued the actual expected value, converting the expected value into the potentiometer expected value based on the potentiometer calibration value corresponding to the calibrated sieve opening (5mm-25mm); 4. Determining whether the potentiometer expected value is not equal to the potentiometer current value; 5. When the potentiometer expected value is not equal to the potentiometer current value, calculating the error value in real time: Potentiometer error value = Potentiometer expected value - Potentiometer current value (hereinafter referred to as "error", unit mV), and ending.

[0066] Technical solution for segmented PWM positioning control of screen motor, such as Figure 4 As shown.

[0067] In step 5 of the above scheme (technical scheme for controlling the screen plate adjustment motor), when the "target value release" button is triggered from the HMI terminal, the control system will immediately start the screen plate motor positioning control. The specific steps are as follows.

[0068] Step 1: Initialize the system to prepare for motor (screen motor 107) control. In the initial state, output a 0% PWM control signal to the motor to keep it stationary.

[0069] Step 2: The error input of the control system is the potentiometer error described in Step 5 of the technical solution (screen plate adjustment motor control method). The error value is monitored in real time, and its absolute value Abs (error) is calculated.

[0070] If Abs(error) > 30: Further determine the sign of the error value.

[0071] If the error is greater than 0 and the error is greater than or equal to 30, proceed to step 3, the screen opening increase control method.

[0072] If the error is less than 0 and less than or equal to -30, proceed to step 4, the screen opening reduction control method.

[0073] Step 3: Method for controlling the increase of sieve opening

[0074] Adjust the duty cycle of the PWM output signal in segments according to the magnitude of Abs(error).

[0075] If Abs(error) > 400, the PWM outputs a +100% control signal.

[0076] If 200 < Abs(error) ≤ 400, the PWM outputs a +65% control signal; otherwise, the PWM outputs a +100% control signal.

[0077] If 100 < Abs(error) ≤ 200, the PWM outputs a +40% control signal; otherwise, the PWM outputs a +65% control signal.

[0078] If 30 < Abs(error) ≤ 100, the PWM outputs a +30% control signal; otherwise, the PWM outputs a +40% control signal.

[0079] If Abs(error) ≤ 30, the PWM outputs a 0% control signal and the process ends; otherwise, the PWM outputs a +30% control signal.

[0080] Step 4: Control method for reducing the opening of the sieve plate

[0081] Adjust the duty cycle of the PWM output signal in segments according to the magnitude of Abs(error).

[0082] If Abs(error) > 400, the PWM outputs a -100% control signal.

[0083] If 200 < Abs(error) ≤ 400, the PWM outputs a -65% control signal; otherwise, the PWM outputs a -100% control signal.

[0084] If 100 < Abs(error) ≤ 200, the PWM outputs a -40% control signal; otherwise, the PWM outputs a -65% control signal.

[0085] If 30 < Abs(error) ≤ 100, the PWM outputs a -30% control signal; otherwise, the PWM outputs a -40% control signal.

[0086] If Abs(error) ≤ 30, the PWM outputs a 0% control signal and the process ends; otherwise, the PWM outputs a -30% control signal.

[0087] Step 5: During the positioning control process in Step 3, when "error ≤ -30" is monitored, immediately exit Step 3 and transfer to Step 2; during the positioning control process in Step 4, when "error ≥ 30" is monitored, immediately exit Step 4 and transfer to Step 2.

[0088] By using the above-mentioned segmented PWM signal output technology, the positioning accuracy of the sieve opening motor can be controlled within ±30Mv, with the potentiometer error as the monitored quantity.

[0089] This invention achieves intelligent and automated calibration of the screen motor through the design of an automated calibration process. The development of an error correction algorithm further improves calibration accuracy and stability. The HMI (Hardware Management System) sets the actual expected value of the screen opening and establishes a distribution mechanism to ensure accurate transmission of the target value. A method for converting the expected value into a potentiometer expected value is used to achieve precise conversion between different physical quantities. A real-time error calculation method improves control accuracy. The design of an error compensation algorithm and a system self-calibration function ensures long-term system stability and control accuracy. A segmented PWM signal output positioning control method is used to reduce motor overshoot during positioning control.

[0090] The design advantages of this invention's embodiment in terms of the control system are as follows: Layered network architecture: A layered control architecture is adopted, consisting of HMI → vehicle controller → drive module → motor. Signal transmission is achieved via CAN bus, resulting in strong system scalability and easy integration into the vehicle control system. Potentiometer feedback closed-loop control: Real-time feedback of position signals (in mV) from the motor's built-in potentiometer forms a closed-loop control, ensuring the accuracy and stability of the screen opening adjustment. Automated calibration process: The correspondence between the screen opening and the potentiometer value (K value) is calibrated through the HMI interface, simplifying system initialization configuration and reducing manual intervention costs.

[0091] The advantages of the control algorithm in this embodiment of the invention are as follows: segmented PWM dynamic adjustment: the PWM duty cycle (±100% / ±65% / ±40% / ±30%) is set in segments according to the absolute value of the error (Abs(error)) to realize the dynamic switching between coarse and fine adjustment, taking into account both adjustment speed and accuracy.

[0092] The advantages of this invention in terms of anti-interference and fault tolerance mechanisms are as follows: Adaptive error direction: During adjustment, the error direction (positive / negative) is monitored in real time, and the control logic is dynamically switched to increase or decrease to avoid overshoot. Rapid response to abnormal states: When the error direction changes abruptly (e.g., error ≤-30 or ≥30 in step 5), the current control flow is immediately interrupted and the error is reassessed to prevent system oscillation. High positioning accuracy: Through segmented PWM control, the potentiometer error is ultimately limited to within ±30mV, meeting the accuracy requirements for sieve opening adjustment.

[0093] like Figure 5 and Figure 6As shown, the present invention also provides a combine harvester screen adjustment device for performing a combine harvester screen adjustment method as described in any of the above claims. The combine harvester screen adjustment device includes: a screen motor 107, a screen adjustment connecting rod 102, a screen adjustment crankshaft 101, a screen 103, an HMI 109, a vehicle controller 110, and a drive module 111. The screen motor 107 is connected to the screen adjustment connecting rod 102. The screen adjustment connecting rod 102 has a groove. The screen adjustment crankshaft 101 is installed in the groove on the screen adjustment connecting rod 102. The screen is connected to the screen adjustment crankshaft. The vehicle controller is connected to the HMI 109, the drive module 111, and the screen motor 107. The drive module 111 is connected to the screen motor 107.

[0094] The beneficial effects of adopting the technical solution of this invention are as follows: the screen plate adjusting linkage moves parallel under the axial drive of the motor output shaft. Through the groove structure of the screen plate adjusting linkage, it drives the screen plate adjusting crankshaft to rotate, thereby realizing the angle adjustment of the screen plates and thus the opening adjustment between adjacent screen plates. By driving the screen plate adjusting linkage with the motor, the axial motion of the motor is converted into the rotation angle adjustment of the screen plates. The mechanical structure is compact, the transmission efficiency is high, and there is no need for complex gear sets. By utilizing the groove structure of the screen plate adjusting linkage in cooperation with the crankshaft, the precise conversion from linear motion to rotational motion is achieved, meeting the continuous adjustment requirements of the screen plate opening.

[0095] Further, the screen motor 107 is a DC brushless geared motor, a stepper motor, or a servo motor; the screen motor 107 is connected to a motor output shaft 106, the motor output shaft 106 is connected to a motor transition link 105, the motor transition link 105 is connected to the screen adjustment link 102 by bolts 104, and a manual adjustment knob 108 is installed at the tail end of the screen motor 107; the HMI 109 is connected to the vehicle controller 110 via a CAN bus, the vehicle controller 110 is connected to the drive module 111 via CAN communication, and the drive module 111 is connected to the screen motor 107 via a hard-wired signal; when the screen motor 107 is a DC brushless geared motor, the DC brushless geared motor has a built-in potentiometer, and the potentiometer is connected to the vehicle controller 110 via a hard-wired signal; when the screen motor is a servo motor, the servo motor is connected to an encoder.

[0096] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: The use of a brushless geared motor as the drive component for screen adjustment significantly reduces costs compared to the electric control system using an electric actuator. The use of a DC brushless geared motor offers greater adaptability to the working environment compared to an electric actuator. The manual adjustment knob at the end of the DC brushless geared motor retains the basic function of manual adjustment. The manual adjustment knob at the end of the screen motor retains a mechanical redundancy design, ensuring that the screen opening can still be adjusted manually in the event of a screen motor failure or power outage, thus improving system reliability. The potentiometer signal built into the DC brushless geared motor is connected to the vehicle controller via a hard-wired signal, providing feedback on the current position of the DC brushless geared motor to the vehicle controller as a potentiometer signal. Utilizing the real-time position signal feedback from the built-in potentiometer of the screen motor forms a closed-loop control, ensuring the accuracy and stability of the screen opening adjustment. The DC brushless geared motor drives a linkage mechanism, converting the axial motion of the motor into the rotation angle adjustment of the screen, resulting in a compact mechanical structure, high transmission efficiency, and eliminating the need for complex gear sets. By utilizing the grooved structure of the screen adjustment linkage in conjunction with the crankshaft, precise conversion from linear motion to rotary motion is achieved, meeting the requirement for continuous adjustment of the screen opening. A hierarchical control architecture of HMI → vehicle controller → drive module → motor is adopted, with signal transmission via CAN bus. The system boasts strong scalability and is easy to integrate into the vehicle control system. As an alternative, a stepper motor + open-loop control is used, eliminating the need for potentiometer feedback and achieving position control through pulse counting, resulting in lower costs. As yet another alternative, a servo motor + encoder feedback is employed. The encoder's resolution is significantly higher than that of a potentiometer, making it suitable for scenarios requiring higher precision.

[0097] As an alternative to the aforementioned types of screen plate motors, users can select different types of screen plate motors according to their actual needs. Examples include, but are not limited to, the following:

[0098] Option 1: Stepper motor + open-loop control; The advantage of this option is that it does not require potentiometer feedback, and position control is achieved through pulse counting, resulting in lower cost.

[0099] Option 2: Servo motor + encoder feedback; The advantage of this option is that the encoder resolution is much higher than that of the potentiometer (e.g., 0.1° accuracy), making it suitable for scenarios requiring higher precision.

[0100] The embodiments of this invention solve the following problems existing in the prior art: 1. Cost issue: The screen adjustment involved in this invention uses a brushless geared motor as the driving component, which significantly reduces the cost compared to the electric control system of the electric push rod adjustment in the prior art. 2. Reliability issue: The present invention uses a DC brushless geared motor, which is more adaptable to the working environment than the electric push rod in the prior art. 3. Screen adjustment issue: The vehicle controller of this invention adopts a control method of segmented PWM signal control of the screen motor (DC brushless geared motor), which solves the overshoot problem caused by traditional PID control motors and reduces the debugging difficulty.

[0101] The technical solution of the sieve adjustment structure in this embodiment of the invention may include, but is not limited to:

[0102] (1) Screen adjustment structure scheme

[0103] like Figure 5 As shown, the output shaft 106 of the DC brushless geared motor (screen motor 107) is connected to the screen adjustment linkage 102 via a motor transition linkage 105 and a bolt 104. The screen adjustment linkage 102 moves parallel under the axial drive of the motor output shaft 106. Through the groove structure of the screen adjustment linkage 102, it drives the screen adjustment crankshaft 101 to rotate, thereby adjusting the angle of the screen 103 and thus adjusting the opening between adjacent screens 103. The manual adjustment knob 108 at the tail end of the DC brushless geared motor (screen motor 107) retains the basic function of manual adjustment.

[0104] (2) Technical solution for sieve adjustment and control system

[0105] Control system network structure technical solutions such as Figure 6 As shown, HMI109 is connected to vehicle controller 110 via CAN bus; vehicle controller 110 is connected to drive module 111 via CAN communication; drive module 111 is connected to screen motor 107 (DC brushless geared motor) via hard-wired signal; the potentiometer signal built into screen motor 107 (DC brushless geared motor) is connected to vehicle controller 110 via hard-wired signal, and the current position of motor (DC brushless geared motor) is fed back to vehicle controller 110 in the form of potentiometer signal.

[0106] The mechanical structure design advantages of the embodiments of the present invention may include, but are not limited to, the following:

[0107] (1) High-efficiency transmission and simplified structure: The axial motion of the motor is converted into the rotation angle adjustment of the screen plate 103 by driving the linkage mechanism (screen plate adjustment linkage 102, motor transition linkage 105 and screen plate adjustment crankshaft 101) through the DC brushless geared motor (screen plate motor 107). The mechanical structure is compact, the transmission efficiency is high, and there is no need for complex gear sets.

[0108] (2) Manual / electric dual-mode compatibility: The manual adjustment knob 108 at the end of the motor retains the mechanical redundancy design, ensuring that the screen opening can still be adjusted manually in the event of motor failure or power failure, thereby improving system reliability.

[0109] (3) Linear displacement and angle coupling: The groove structure of the sieve plate adjusting connecting rod 102 is used to cooperate with the crankshaft 101 to realize the precise conversion from linear motion to rotational motion, and meet the continuous adjustment requirements of the sieve plate opening.

[0110] Those skilled in the art will understand that all or part of the steps of the above-described method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When executed, the program performs the steps of the above-described method embodiments; and the aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks.

[0111] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for adjusting the screen plates of a combine harvester, characterized in that, include: S1. Calibrate the screen motor to obtain the correspondence between the upper and lower limit ranges of the screen opening and the upper and lower limit position potential count value ranges of the screen motor. S2. Obtain the current value of the sieve motor potentiometer, the actual expected value of the sieve opening, and the sieve motor control strategy; wherein, the sieve motor control strategy is segmented PWM signal control; S3. Based on the correspondence between the upper and lower limit ranges of the sieve opening and the upper and lower limit position potential count value ranges of the sieve motor, the actual expected value of the sieve opening is converted into the expected value of the motor potentiometer. S4. Calculate the expected value of the adjustment motor potentiometer and the error value of the current value of the sieve plate motor potentiometer in real time; S5. Based on the error value and the screen motor control strategy, control the screen motor to increase or decrease the screen opening.

2. The method for adjusting the screen of a combine harvester according to claim 1, characterized in that, Step S1 includes: S11. Press the screen motor reduce button to adjust the screen to the minimum opening position. On the screen motor calibration interface, press the "calibrate" button to record and save the current potentiometer value of the screen motor. S12. Determine if the HMI indicates successful calibration; S13. When the HMI indicates that the calibration is successful, press the screen motor increase button to adjust the screen to the maximum opening position. On the screen motor calibration interface, press the "calibrate" button to record and save the current potentiometer value of the screen motor. S14. Determine if the HMI indicates successful calibration; S15. When the HMI indicates that the calibration is successful, the calibration ends.

3. The method for adjusting the screen of a combine harvester according to claim 1, characterized in that, Step S3 includes: S31. Obtain the current value of the potentiometer for the sieve plate motor; S32. Convert the current value of the sieve motor potentiometer into the actual value of the sieve opening and display it on the HMI.

4. The method for adjusting the screen of a combine harvester according to claim 1, characterized in that, When the screen motor control strategy is segmented PWM signal control, step S2 includes: when the actual expected value of the screen opening input by the HMI is obtained, the system is initialized to prepare for motor control, and a 0% PWM control signal is output to the screen motor to keep the screen motor stationary.

5. The method for adjusting the screen of a combine harvester according to claim 1, characterized in that, When the screen motor control strategy is segmented PWM signal control, step S5 includes: S51. Calculate the absolute value of the error; S52. Determine whether the absolute value of the error is greater than 30; S53. When the absolute value of the error is greater than 30, determine whether the error is positive or negative; S54. When the error value is greater than 0 and not less than 30, the duty cycle of the PWM output signal is adjusted in segments according to the magnitude of the error to control the screen motor to increase the screen opening. S55. When the error value is less than 0 and the error value is not greater than -30, the duty cycle of the PWM output signal is adjusted in segments according to the magnitude of the error to control the screen motor to reduce the screen opening.

6. The method for adjusting the screen of a combine harvester according to claim 5, characterized in that, When the screen motor control strategy is segmented PWM signal control, step S54 includes: If the absolute value of the error is greater than 400, the PWM output will be a +100% control signal. If the absolute value of the error is greater than 200 and not greater than 400, the PWM outputs a +65% control signal; If the absolute value of the error is greater than 100 and not greater than 200, the PWM outputs a +40% control signal; If the absolute value of the error is greater than 30 and not greater than 100, the PWM outputs a +30% control signal; If the absolute value of the error is not greater than 30, the PWM outputs a 0% control signal and the process ends. Step S55 includes: If the absolute value of the error is greater than 400, the PWM output will be a -100% control signal. If the absolute value of the error is greater than 200 and not greater than 400, the PWM outputs a -65% control signal. If the absolute value of the error is greater than 100 and not greater than 200, the PWM outputs a -40% control signal; If the absolute value of the error is greater than 30 and not greater than 100, the PWM outputs a -30% control signal; If the absolute value of the error is not greater than 30, the PWM outputs a 0% control signal and the process ends.

7. A method for adjusting the screen of a combine harvester according to claim 6, characterized in that, When the screen motor control strategy is segmented PWM signal control, in step S54, if the error value is not greater than -30, immediately exit step S54 and execute step S52. In step S55, if the error value is not less than 30, immediately exit step S55 and execute step S52.

8. A screen adjustment device for a combine harvester, characterized in that, A combine harvester screen adjustment method according to any one of claims 1 to 7, the combine harvester screen adjustment device includes: a screen motor, a screen adjustment connecting rod, a screen adjustment crankshaft, a screen, an HMI, a vehicle controller, and a drive module. The screen motor is connected to the screen adjustment connecting rod, the screen adjustment connecting rod has a groove, the screen adjustment crankshaft is installed in the groove on the screen adjustment connecting rod, the screen is connected to the screen adjustment crankshaft, the vehicle controller is connected to the HMI, the drive module, and the screen motor, and the drive module is connected to the screen motor.

9. A combine harvester screen adjustment device according to claim 8, characterized in that, The screen motor is a DC brushless geared motor, a stepper motor, or a servo motor; the screen motor is connected to a motor output shaft, the motor output shaft is connected to a motor transition link, the motor transition link is connected to the screen adjustment link by bolts, and a manual adjustment knob is installed at the tail end of the screen motor; the HMI is connected to the vehicle controller via a CAN bus, the vehicle controller is connected to the drive module via CAN communication, and the drive module is connected to the screen motor via a hard-wired signal; When the screen motor is a DC brushless geared motor, the DC brushless geared motor has a built-in potentiometer, which is connected to the vehicle controller via a hard-wired signal. When the screen motor is a servo motor, the servo motor is connected to an encoder.

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