A longitudinal axis flow threshing intensity grading rotary control screen and automatic control method

Abstract

The present application is suitable for the technical field of threshing and separating of combine harvester and self-adaptive control, and specifically provides a longitudinal axial flow threshing intensity grading rotary control screen, which comprises a grading control execution mechanism, a sensing system, a controller, a motor driver and a liquid crystal display; the grading control execution mechanism comprises a rotary control screen, a boss, a connecting rod, a pin shaft and an electric push rod. The present application also provides an automatic control method. On the basis of the existing threshing mechanism of the combine harvester, a grading rotary control screen is designed, working information collected by the sensing system is input into the single-chip microcomputer controller for processing by a multi-information fuzzy control algorithm and a prediction algorithm, a corresponding control strategy is selected to drive the execution mechanism to work, so as to realize the automatic control of changing the threshing intensity and grading according to different working conditions, avoid blockage and display the working state of the unit in real time.

Description

Technical Field

[0001] This invention belongs to the field of combine harvester threshing and adaptive control technology, and particularly relates to a longitudinal axial flow threshing intensity grading rotary control screen and automatic control method. Background Technology

[0002] With the rapid development of technology, the agricultural sector is also undergoing unprecedented changes.

[0003] Intelligentization has become an important symbol of modern agriculture. The application of intelligent technologies can effectively improve the yield, quality and efficiency of agricultural production, and greatly improve the working conditions of farmers.

[0004] The threshing and separating device is a core component of the combine harvester. Its function is to separate the grains from the stalks, and its performance directly determines the working performance of the combine harvester.

[0005] Currently, longitudinal axial flow threshing devices often suffer from problems such as insufficient threshing, incomplete separation, and clogging when crop feed fluctuates significantly. For example, Chinese invention patent application number 201810558496.2 discloses an adjustable longitudinal axial flow threshing and separation screen, which adds a side arc plate under the concave plate screen and changes the threshing intensity by opening and closing the side arc plate. However, this is insufficient to provide graded control of the threshing intensity according to different operating conditions, affecting the threshing intensity accuracy and working efficiency of the combine harvester. Summary of the Invention

[0006] The purpose of this invention is to provide a longitudinal axial flow threshing intensity grading rotary control screen and an automatic control method, which aims to solve the technical problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides a longitudinal axial flow threshing intensity grading rotary control screen and an automatic control method. By detecting the crop pressure at the bridge outlet through sensors to estimate the feed rate, the rotary control screen is adjusted to achieve graded control of threshing intensity. At the same time, the torque of the threshing drum is monitored by sensors to avoid clogging and maintain optimal threshing intensity and good adaptability.

[0008] In a first aspect of the present invention, a longitudinal axial flow threshing intensity grading rotary control screen is provided, comprising a grading control actuator, a sensing system, a controller, a motor driver, and a liquid crystal display.

[0009] The graded control actuator includes a rotary control screen, a boss, a connecting rod, a pin, and an electric push rod;

[0010] The rotary control screen is rotatably mounted on the matching track of the support. The rotary control screen is equipped with a boss, which is hinged to the connecting rod. The connecting rod is hinged to the moving joint of the electric push rod through a pin. The electric push rod is connected to the motor.

[0011] As a further embodiment of the present invention, one end of the rotary control screen is provided with a spiral feed head, which can rotate and feed the grains in.

[0012] It also includes an upper end cover, the end of which is fixedly installed with a front end baffle by bolts and nuts, the upper front end of the support screen is fixedly connected to the front end mounting plate, and the front end mounting plate is fixedly connected to the front end baffle.

[0013] It also includes a threshing drum shaft, which is connected to a screw feed head. When the threshing drum shaft rotates, it drives the screw feed head to rotate.

[0014] It also includes a tongue plate, which is fixedly connected to the lower front end of the support screen by bolts.

[0015] As a further aspect of the present invention, it also includes a push-button switch and a status indicator light, wherein the push-button switch, status indicator light, motor driver and liquid crystal display are installed in the cab of the rice and wheat combine harvester.

[0016] As a further embodiment of the present invention, the push-button switch is connected to the power supply, the status indicator light, and the motor driver respectively;

[0017] The motor driver is connected to the motors in the controller and the hierarchical control actuator, respectively.

[0018] The controller is connected to both the LCD display and the sensing system.

[0019] The sensing system includes sensors and conditioning circuitry for measuring the current pressure at the bridge outlet and the torque of the threshing drum.

[0020] The LCD screen displays the feed rate, torque information, and working status of the rotary control screen in real time. The feed rate and torque are monitored by a sensor system, and the rotation of the motor is controlled by a controller and motor driver to drive the rotation of the rotary control screen.

[0021] In a second aspect of the present invention, an automatic control method is provided, the control method comprising:

[0022] A multi-information fuzzy control model is established, and the pressure and torque information collected by the sensing system is input to the controller.

[0023] The controller selects the appropriate control strategy based on the established multi-information fuzzy control model to control the motor driver. The motor driver drives the electric push rod to make linear motion, which in turn drives the rotary control screen to rotate.

[0024] As a further aspect of the present invention, the pressure information acquisition step includes: acquiring pressure information at the bridge outlet using a sensor; the torque information acquisition includes acquiring torque information of the threshing drum using a sensor.

[0025] As a further aspect of the present invention, the process by which the controller selects the appropriate control strategy to control the motor driver based on the established multi-information fuzzy control model includes:

[0026] The feed rate across the bridge is estimated based on the pressure information at the bridge outlet.

[0027] Based on the grading results of the estimated bridge feed rate, the rotary control screen is subjected to graded control.

[0028] The rotary control screen is subjected to preset PID control based on the drum torque information.

[0029] As a further aspect of the present invention, the control strategy for graded control of the rotary control screen based on the grading results of the estimated bridge feed rate is as follows:

[0030] When the feed rate is less than or equal to 5 kg / s, the rotary control screen is fully closed, and the threshing intensity is the maximum.

[0031] When the feed rate is between 5 kg / s and 8 kg / s, the rotary control screen is opened to 1 / 3 to slightly reduce the threshing intensity.

[0032] When the feed rate is greater than or equal to 8 kg / s, the rotary control screen opens to 2 / 3 to reduce the threshing intensity and decrease the probability of grain breakage.

[0033] As a further aspect of the present invention, the step of performing preset PID control on the rotary control screen based on drum torque information includes:

[0034] When the torque is not overloaded, do not interfere with the rotary control screen;

[0035] When the torque is overloaded, the rotary control screen opens to prevent clogging.

[0036] As a further aspect of the present invention, in the process of collecting pressure information at the bridge outlet using a sensor, considering that the grain inside the bridge is very likely to interfere with the pressure sensor and the force-bearing surface of the sensor is too small, a force-bearing plate is added to the sensor so that both ends of the force-bearing plate are tangent to the inclined plate surface of the bridge, so as to increase the force-bearing surface and isolate the grain interference.

[0037] Compared with the prior art, the beneficial effects of the present invention are:

[0038] First, the longitudinal axial flow threshing intensity grading rotary control screen of the present invention, activated by a push-button switch, causes the push rod of the electric pusher to extend and retract linearly, pulling the rotary control screen to swing around the support screen via a connecting rod, thus achieving automatic grading control of threshing intensity. When the program selection switch is not activated, the rectangular screen holes of the rotary control screen coincide with the screen holes of the support screen, i.e., the rotary control screen is fully open, avoiding clogging; the LCD display shows the feed rate, torque information, and the working status of the rotary control screen in real time. The feed rate and torque are monitored by a sensor system, and the rotation of the motor is controlled by the controller and motor driver to drive the rotation of the rotary control screen, thereby achieving automatic grading control of threshing intensity, while the unit's working status is displayed on the LCD screen.

[0039] Secondly, the automatic control method of the present invention achieves automatic graded control of threshing intensity under the condition that the longitudinal axial flow threshing intensity grading rotary control screen is blocked. Specifically, the feed amount is estimated by detecting the crop pressure at the bridge outlet through the sensor, and then the rotary control screen is adjusted to achieve graded control of threshing intensity. At the same time, the torque of the threshing drum is monitored by the sensor to avoid blockage and maintain the best threshing intensity and good adaptability.

[0040] In summary, based on the existing threshing mechanism of the combine harvester, a graded rotary control screen was designed. The working information collected by the sensing system is fed into the microcontroller for processing by multi-information fuzzy control algorithm and prediction algorithm. The appropriate control strategy is selected to drive the actuator to work, thereby realizing the change of threshing intensity and graded automatic control for different working conditions. At the same time, it can avoid blockage and display the unit's working status in real time. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention.

[0042] Figure 1 This is a schematic diagram of the actuator of the threshing intensity grading control device in the longitudinal axial flow threshing intensity grading rotary control screen of the present invention;

[0043] Figure 2 This is a schematic diagram of the structural connection of the threshing intensity grading control device;

[0044] Figure 3 for Figure 2 Schematic diagram of multi-information fuzzy control principle of the controller;

[0045] Figure 4 for Figure 2 Flowchart of the main program of controller 22;

[0046] Figure 5 for Figure 4 Flowchart of the multi-information fuzzy control algorithm subroutine for controller 22.

[0047] In the attached diagram: 1. Front mounting plate; 2. Bolts and nuts; 3. Front baffle; 4. Top cover; 5. Threshing drum shaft; 6. Screw feed head; 7. Tongue plate; 8. Support screen; 9. Boss; 10. Connecting rod; 11. Pin; 12. Motor; 13. Electric push rod; 14. Rotary control screen; 15. Track; 16. Power supply; 17. Push button switch; 18. Status indicator light; 19. Motor driver; 20. Grading control actuator; 21. Sensing system; 22. Controller; 23. LCD display. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0049] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.

[0050] like Figure 2 As shown, in a first aspect of the present invention, a longitudinal axial flow threshing intensity grading rotary control screen is provided, including a grading control actuator 20, a sensing system 21, a controller 22, a motor driver 19, and a liquid crystal display 23.

[0051] It also includes a push-button switch 17 and a status indicator light 18. The push-button switch 17, status indicator light 18, motor driver 19 and LCD display 23 are installed in the cab of the rice and wheat combine harvester.

[0052] Specifically, such as Figure 1 As shown, the graded control actuator 20 of the present invention includes a rotary control screen 14, a boss 9, a connecting rod 10, a pin 11, and an electric push rod 13;

[0053] The rotary control screen 14 is rotatably mounted on the mating track 15 of the support 8. The rotary control screen 14 is equipped with a boss 9, which is hinged to the connecting rod 10. The connecting rod 10 is hinged to the moving joint of the electric push rod 13 through the pin 11. The electric push rod 13 is connected to the motor 12.

[0054] Furthermore, the diameter of the rotary control screen 14 is slightly larger than that of the concave plate screen; there is an arc guide rail inside the track 15, which is used to fix the position of the rotary control screen 14.

[0055] Preferably, the boss 9 on the rotary control screen 14 is connected to two connecting rods 10.

[0056] Furthermore, a spiral feed head 6 is provided at one end of the rotary control screen 14, which can feed the grains in a rotary manner.

[0057] It also includes an upper end cover 4, the end of which is fixedly installed with a front end baffle 3 by bolts and nuts 2, the upper front end of the support screen 8 is fixedly connected to the front end mounting plate 1, and the front end mounting plate 1 and the front end baffle 3 are fixedly connected.

[0058] Furthermore, it also includes a threshing drum shaft 5, which is connected to a screw feed head 6. When the threshing drum shaft 5 rotates, it drives the screw feed head 6 to rotate.

[0059] Furthermore, it also includes a tongue plate 7, which is fixedly connected to the lower front end of the support screen 8 by bolts.

[0060] When the operator is operating the rice and wheat combine harvester, the controller 22 is activated by the push button switch 17, causing the push rod of the electric push rod 13 to extend and retract linearly. This, through the connecting rod 10, pulls the rotary control screen 14 to swing around the support screen 8, achieving automatic control of threshing intensity grading. When the program selection switch is not activated, the rectangular screen holes of the rotary control screen 14 coincide with the screen holes of the support screen 8, meaning the rotary control screen 14 is fully open, preventing clogging.

[0061] like Figure 2 The push button switch 17 of the present invention is connected to the power supply 16, the status indicator light 18 and the motor driver 19 respectively.

[0062] The motor driver 19 is connected to the controller 22 and the motor 12 in the hierarchical control actuator 20.

[0063] The controller 22 is connected to the LCD display 23 and the sensing system 21. The controller 22 consists of a microcontroller and its peripheral circuits. The sensing system 21 includes sensors and conditioning circuits for measuring the pressure at the current bridge outlet and the torque of the threshing drum. The two types of sensors are installed in corresponding parts of the combine harvester.

[0064] The LCD display 23 displays the feed rate, torque information, and working status of the rotary control screen in real time. The feed rate and torque are monitored by the sensor system 21. The rotation of the motor 12 is controlled by the controller 22 and the motor driver 19 to drive the rotation of the rotary control screen 14, thereby realizing automatic control of threshing intensity grading. At the same time, the working status of the unit is displayed on the LCD display 23.

[0065] In a second aspect of the invention, an automatic control method is also provided, which is based on the longitudinal axial flow threshing intensity grading rotary control screen provided in the first aspect of the invention.

[0066] The automatic control method includes a signal detection process implemented by a signal detection program, a multi-information fuzzy control process implemented by a multi-information fuzzy control algorithm, and a motor control process implemented by a motor control program.

[0067] Specifically, in this invention, when the button switch 17 is not pressed, the status indicator light 18 is off, the hierarchical control actuator 20 is fully open, and the LCD display 23 shows its working status. When the button switch 17 is pressed, the power supply to the motor driver 19 is turned on, the status indicator light 18 lights up, the hierarchical control actuator 20 starts, and the LCD display 23 shows its working status.

[0068] Specifically, the control method of the present invention includes:

[0069] A multi-information fuzzy control model is established, and the pressure and torque information collected by the sensing system is input to the controller.

[0070] The controller selects the appropriate control strategy based on the established multi-information fuzzy control model to control the motor driver. The motor driver drives the electric push rod to make linear motion, which in turn drives the rotary control screen to rotate.

[0071] The pressure information acquisition step includes: acquiring pressure information at the bridge outlet using a sensor; the torque information acquisition includes acquiring torque information of the threshing drum using a sensor.

[0072] The process by which the controller selects the appropriate control strategy to control the motor driver based on the established multi-information fuzzy control model includes:

[0073] The feed rate across the bridge is estimated based on the pressure information at the bridge outlet.

[0074] Based on the grading results of the estimated bridge feed rate, the rotary control screen is subjected to graded control.

[0075] The rotary control screen is subjected to preset PID control based on the drum torque information.

[0076] Furthermore, based on the grading results of the estimated feed rate across the bridge, the control strategy for grading the rotary control screen is as follows:

[0077] When the feed rate is less than or equal to 5 kg / s, the rotary control screen is fully closed, and the threshing intensity is the maximum.

[0078] When the feed rate is between 5 kg / s and 8 kg / s, the rotary control screen is opened to 1 / 3 to slightly reduce the threshing intensity.

[0079] When the feed rate is greater than or equal to 8 kg / s, the rotary control screen opens to 2 / 3 to reduce the threshing intensity and decrease the probability of grain breakage.

[0080] Furthermore, the steps for pre-setting PID control of the rotary control screen based on drum torque information include:

[0081] When the torque is not overloaded, do not interfere with the rotary control screen;

[0082] When the torque is overloaded, the rotary control screen opens to prevent clogging.

[0083] During the process of collecting pressure information at the bridge outlet using sensors, considering that the grain inside the bridge is very likely to interfere with the pressure sensor and the sensor's force-bearing surface is too small, a force-bearing plate was added to the sensor so that both ends of the force-bearing plate are tangent to the inclined plate of the bridge, in order to increase the force-bearing surface and isolate the grain interference.

[0084] When the graded control actuator 20 is in automatic control, it collects pressure information at the bridge outlet and torque information of the threshing drum shaft through the sensing system 21. After the collected signals are filtered and stabilized by the conditioning circuit, they are input to the controller 22 for processing. After the controller 22 processes the control algorithm, it selects the corresponding control strategy to control the motor driver 19 to work. The motor driver 19 drives the motor 12 to rotate, which drives the connecting rod 10 to drive the rotating control screen 14 to swing, thereby achieving the purpose of graded control of threshing intensity.

[0085] Furthermore, the purpose of graded control of threshing intensity is to achieve automatic graded control of threshing intensity under conditions of blockage and different feed rates. The threshing process is a complex system, and the performance status of each component, as well as the properties of the crop and the ground conditions, are constantly changing, which brings great difficulties to the application of traditional control theory.

[0086] Fuzzy control theory is based on expert experience, rules, and self-learning capabilities. It infers from the measured values ​​and changes of the controlled object to keep the control target stable near the expected value.

[0087] like Figure 3 As shown, this invention applies fuzzy control technology to a threshing intensity grading control system. This system is a dual-input control system, and a multi-information fuzzy control model is established. Pressure and torque signals measured by two sensors are preprocessed and compared with their respective setpoints to establish a fuzzy controller. Figure 3 The preset controller in the system uses the feed rate as the main input control quantity and overload blockage as the monitoring quantity. Through optimization and judgment, it controls the threshing intensity in a graded manner.

[0088] Furthermore, the controller 22 selects the appropriate control strategy to control the motor driver 19 based on the established multi-information fuzzy control model. The basic control strategy is:

[0089] Feed rate information is obtained from the processed pressure information. When the feed rate is less than or equal to 5 kg / s, the extension distance of the electric push rod 13 is controlled to make the rotary control screen 14 fully closed, that is, the solid part of the rotary control screen 14 completely blocks the screen holes of the support screen 8. At this time, the threshing intensity is the maximum, increasing the rubbing force between the threshing teeth and the grain, which is conducive to grain separation. When the feed rate is between 5 kg / s and 8 kg / s, the extension distance of the electric push rod 13 is controlled to make the rotary control screen 14 rotate to the position where 1 / 3 of the screen hole area of ​​the support screen 8 is exposed, slightly reducing the threshing intensity. When the feed rate is greater than or equal to 8 kg / s, the extension distance of the electric push rod 13 is controlled to make the rotary control screen 14 rotate to the position where 2 / 3 of the screen hole area of ​​the support screen 8 is exposed, reducing the threshing intensity and reducing the probability of grain breakage. The load information of the threshing drum shaft is obtained from the processed torque information. When overload occurs at any stage, the controller 22 interferes with the rotary control screen 14. Based on the overload ratio, the controller controls the extension distance of the electric push rod 13 to rotate the rotary control screen 14 to a position where a certain area of ​​the support screen 8 screen holes is exposed, so that the threshing drum shaft is in the optimal state of safe load operation. The graded control of threshing intensity is determined by a multi-information fuzzy control algorithm.

[0090] The following is the design process of the fuzzy controller for the shaft torque of the threshing drum:

[0091] The torque control strategy for the threshing drum shaft is a two-dimensional fuzzy controller. The inputs are the load deviation FE and the rate of change of deviation FEC, and the output is the extension and retraction of the electric push rod 13, U. The fuzzy sets of the load deviation FE and the rate of change of load deviation FEC of the threshing drum shaft are defined as {NB, NM, NS, ZO, PS, PM, PB}. The basic universes of discourse for FE and FEC are [-6,6], and the basic universe of discourse for U is [0,1]. The membership function is a triangular function. The fuzzy control rules are established as shown in Table 1. The output is sent to the controlled object after fuzzification, fuzzy inference and defuzzification of the fuzzy control.

[0092]

[0093] Table 1

[0094] like Figure 4 As shown, after the main program of the threshing strength grading controller initializes the system, it controls the electric push rod 13 to return to center so that the rectangular screen holes of the rotary control screen 14 are completely aligned with the screen holes of the support screen 8. First, it calls the data acquisition program and the LCD display program to collect data and display the working status. Then, it selects whether to start the control program. If the automatic control mode is selected, it calls the multi-information fuzzy control algorithm program.

[0095] like Figure 5As shown, the multi-information fuzzy control algorithm program sequentially calls the input fuzzification program, the rule base and database, the fuzzy inference program, the output defuzzification program, and the control strategy. Then, based on the algorithm results, it determines whether the extension / retraction of the electric push rod 13 needs adjustment. If adjustment is required, the motor control program is called to reasonably regulate the extension / retraction of the electric push rod 13, thereby driving the connecting rod to drive the rotation of the rotary control screen 14 to achieve automatic graded control of threshing intensity.

[0096] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. It can be applied to various fields suitable for the present invention. Other modifications can be readily made by those skilled in the art. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and examples shown and described herein.

Claims

1. A longitudinal axial flow threshing intensity grading rotary control screen, comprising a grading control actuator (20), a sensing system (21), a controller (22), a motor driver (19), and a liquid crystal display (23). The graded control actuator (20) includes a rotary control screen (14), a boss (9), a connecting rod (10), a pin (11), and an electric push rod (13). Its features are: The rotary control screen (14) is rotatably mounted on the matching track (15) of the support screen (8). The rotary control screen (14) is equipped with a boss (9). The boss (9) is hinged to the connecting rod (10). The connecting rod (10) is hinged to the moving joint of the electric push rod (13) through the pin (11). The electric push rod (13) is connected to the motor (12). The solid part of the rotary control screen (14) is used to block the screen holes of the support screen (8). The push rod of the electric push rod (13) makes a telescopic linear motion, and pulls the rotary control screen (14) around the support screen (8) through the connecting rod (10). The threshing intensity is automatically controlled by the overlapping area of ​​the rectangular screen holes of the rotary control screen (14) and the screen holes of the support screen (8). Hierarchical automatic control strategies include: When the feed rate is less than or equal to 5 kg / s, the push distance of the electric push rod (13) is controlled to make the rotary control screen (14) reach a fully closed state, and the solid part of the rotary control screen (14) completely covers the screen hole of the support screen (8). When the feed rate is between 5 kg / s and 8 kg / s, the push distance of the electric push rod (13) is controlled to make the rotary control screen (14) rotate to the position where 1 / 3 of the screen hole area of ​​the support screen (8) is exposed. When the feed rate is greater than or equal to 8 kg / s, the push distance of the electric push rod (13) is controlled to make the rotary control screen (14) rotate to the position where 2 / 3 of the screen hole area of ​​the support screen (8) is exposed; The load information of the threshing drum shaft is obtained from the torque information. When the load is overloaded, the controller (22) interferes with the rotary control screen (14). According to the overload ratio, the push distance of the electric push rod (13) is controlled so that the rotary control screen (14) rotates to a position where a certain area of ​​the support screen (8) screen hole is exposed, so that the threshing drum shaft is in the best state of safe load operation. The graded control of threshing intensity is determined by the multi-information fuzzy control algorithm.

2. The longitudinal axial flow threshing intensity grading rotary control screen according to claim 1, characterized in that, One end of the rotary control screen (14) is provided with a spiral feed head (6); It also includes an upper end cover (4), the end of which is fixedly installed with a front end baffle (3) by bolts and nuts (2), the upper part of the front end of the support screen (8) is fixedly connected to the front end mounting plate (1), and the front end mounting plate (1) and the front end baffle (3) are fixedly connected. It also includes a threshing drum shaft (5), which is connected to a spiral feed head (6); It also includes a tongue plate (7), which is fixedly connected to the lower front end of the support screen (8) by bolts.

3. The longitudinal axial flow threshing intensity grading rotary control screen according to claim 2, characterized in that, It also includes a push-button switch (17) and a status indicator (18), which are installed in the cab of the rice and wheat combine harvester.

4. The longitudinal axial flow threshing intensity grading rotary control screen according to claim 3, characterized in that, The push button switch (17) is connected to the power supply (16), the status indicator (18) and the motor driver (19) respectively. The motor driver (19) is connected to the controller (22) and the motor (12) in the hierarchical control actuator (20), respectively. The controller (22) is connected to the liquid crystal display (23) and the sensing system (21) respectively. The sensing system (21) includes sensors and conditioning circuitry for measuring the current pressure at the bridge outlet and the torque of the threshing drum. The LCD display (23) displays the feed amount, torque information and working status of the rotary control screen in real time. The feed amount and torque are monitored by the sensor system (21). The rotation of the motor (12) is controlled by the controller (22) and the motor driver (19) to drive the rotation of the rotary control screen (14).

5. An automatic control method for a longitudinal axial flow threshing intensity grading rotary control screen as described in any one of claims 1-4, characterized in that, The automatic control method includes: A multi-information fuzzy control model is established, and the pressure and torque information collected by the sensing system is input to the controller. The controller selects the appropriate control strategy based on the established multi-information fuzzy control model to control the motor driver. The motor driver drives the electric push rod to make linear motion, which in turn drives the rotary control screen to rotate.

6. The automatic control method according to claim 5, characterized in that, The pressure information acquisition steps include: acquiring pressure information at the bridge exit using sensors; The acquisition of torque information includes collecting torque information of the threshing drum using sensors.

7. The automatic control method according to claim 6, characterized in that, The process by which the controller selects the appropriate control strategy to control the motor driver based on the established multi-information fuzzy control model includes: The feed rate across the bridge is estimated based on the pressure information at the bridge outlet. Based on the grading results of the estimated bridge feed rate, the rotary control screen is subjected to graded control. The rotary control screen is subjected to preset PID control based on the drum torque information.

8. The automatic control method according to claim 7, characterized in that, Based on the grading results of the estimated feed rate across the bridge, the control strategy for grading control of the rotary control screen is as follows: When the feed rate is less than or equal to 5 kg / s, the rotary control screen is fully closed. When the feed rate is between 5 kg / s and 8 kg / s, the rotary control screen opens to 1 / 3. When the feed rate is greater than or equal to 8 kg / s, the rotary control screen is opened to 2 / 3.

9. The automatic control method according to claim 8, characterized in that, The steps for pre-setting PID control of the rotary control screen based on drum torque information include: When the torque is not overloaded, do not interfere with the rotary control screen; When the torque is overloaded, the rotary control screen opens.

10. The automatic control method according to claim 9, characterized in that, During the process of collecting pressure information at the bridge exit using sensors, a force plate is installed on the sensor so that both ends of the force plate are tangent to the inclined plate surface of the bridge.

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