Automatic adjustment system for a disk wheel seed metering device

Abstract

This invention relates to the field of agricultural sowing and discloses an automatic adjustment system for the partition of a spoon-wheel seed metering device. The system includes a detection unit, a control unit, and an execution unit. The detection unit acquires the spoon wheel speed and seed passage status in real time through a speed sensor and a dual photoelectric sensor group. The control unit employs a composite control strategy combining speed feedforward and sowing quality feedback to calculate the optimal partition angle in real time. The execution unit uses a stepper motor to drive a gear that rolls along an arc-shaped rack whose center coincides with the center of the spoon wheel, thereby driving the partition to rotate precisely around the center of the spoon wheel via a transmission connector. This invention achieves adaptive dynamic adjustment of the partition angle through closed-loop control, automatically optimizing based on real-time changes in operating speed and sowing quality. It effectively solves the technical problem of high missed and reseeding rates under varying working conditions with traditional fixed or manual partitions, significantly improving the stability and uniformity of precision sowing.

Description

Technical Field

[0001] This invention relates to the field of agricultural sowing, and specifically to an automatic adjustment system for the partition of a spoon-wheel seed metering device. Background Technology

[0002] Precision seeding is a key technology in modern precision agriculture, and its quality directly affects crop emergence rate, growth uniformity, and final yield. The scoop-wheel seed metering device, due to its simple structure, low seed damage rate, and strong adaptability, is widely used in the sowing of medium-to-large-sized seeds such as corn and soybeans. The working principle of the scoop-wheel seed metering device is that the seed-grabbing scoop on the scoop wheel scoops seeds from the seed box, and during rotation, centrifugal force removes excess seeds, finally delivering individual seeds to the seed delivery tube to complete the sowing process.

[0003] In a scoop-wheel seed metering device, the baffle is one of the core components affecting sowing quality. Located between the scoop wheel and the rear housing of the metering device, the baffle's angle determines the seed's travel distance on the scoop wheel and the size of the seed-cleaning area. An excessively large baffle angle causes seeds to remain on the scoop wheel for too long, making them prone to falling off due to excessive centrifugation or vibration, resulting in missed sowing. Conversely, an excessively small baffle angle leads to incomplete seed cleaning, with excess seeds failing to dislodge in time, causing re-sowing. Therefore, the optimal baffle angle is crucial for ensuring the quality of single-seed sowing.

[0004] Currently, most seed metering machines on the market use fixed or manually adjustable baffles. Fixed baffles cannot adapt to changes in dynamic operating conditions such as different operating speeds, different seed characteristics, and different ground vibrations, resulting in large fluctuations in sowing quality. Although manually adjustable baffles can be adjusted when the machine is stopped, they cannot achieve real-time adjustment during operation and rely on the operator's experience. The adjustment accuracy and response speed cannot meet the requirements of high-speed, high-precision sowing.

[0005] In recent years, some studies have attempted to introduce electromechanical adjustment mechanisms to achieve automatic adjustment of the partitions, but the following technical problems still exist: First, most solutions rely on a single sensor or indirect parameters (such as vibration and sound) to determine sowing quality, which cannot accurately and in real time obtain the missed sowing rate and the re-sowing rate, resulting in insufficient basis for adjustment. Second, existing systems mostly use switch control, which is difficult to adapt to the nonlinear, time-varying, and large hysteresis dynamic characteristics of the spoon wheel seed meterer, especially when the operating speed changes abruptly, it is prone to overshoot or oscillation. Third, missed sowing and re-sowing often restrict each other, and existing systems have failed to establish a dynamic balance mechanism between the two, and cannot automatically find the optimal working point under complex working conditions.

[0006] Therefore, there is an urgent need for an automatic adjustment system for the partitions of a scoop wheel seed metering device that can sense the sowing quality in real time, dynamically adjust the partition angle, and adapt to high-speed and variable working conditions. Summary of the Invention

[0007] The purpose of this invention is to provide an automatic adjustment system for the partition of a spoon-wheel seed metering device, thereby solving at least one of the above-mentioned technical problems.

[0008] The objective of this invention can be achieved through the following technical solutions: An automatic adjustment system for the partition of a spoon-wheel seed metering device includes: The detection feedback unit includes a rotation speed sensing module and a seeding quality sensing module. The rotation speed sensing module is used to detect the rotation speed of the scoop wheel in real time, and the seeding quality sensing module is used to detect the seed flow status through the seed metering tube in real time and provide feedback on the seeding quality. The rotation speed sensing module includes a magnet fixed to the periphery of the scoop wheel and a Hall sensor fixed to the rear shell of the seed metering device. The rotation speed of the scoop wheel is determined by detecting the pulse signal generated by the periodic passing of the magnet.

[0009] The execution unit includes a stepper motor, a gear driven by the stepper motor, an arc-shaped rack meshing with the gear, and a transmission mechanism for connecting and driving the partition; the arc-shaped rack is fixedly installed on the rear housing of the seed meterer, and the center of the arc of the tooth profile of the arc-shaped rack coincides with the center of the spoon wheel; The control unit calculates the target partition angle based on the signals from the speed sensor module and the seeding quality sensor module, and drives the stepper motor to rotate the partition around the center of the spoon wheel to the target angle through gear and rack transmission.

[0010] A further proposed solution involves the following operation of the control unit: Based on the real-time detected rotational speed n of the spoon wheel by the rotational speed sensing module, the corresponding feedforward angle θ of the partition is obtained by querying the preset reference angle lookup table for the rotational speed of the spoon wheel partition. ff ; Based on the signal from the sowing quality sensing module, the sowing quality deviation value is calculated. By combining the feedforward angle of the partition plate with the seeding quality deviation value, a target control command is generated to adjust the partition plate to the target angle. Drive the stepper motor according to the target control command.

[0011] In a further embodiment, the seeding quality sensing module consists of a first photoelectric sensor and a second photoelectric sensor arranged sequentially up and down along the seed's falling direction. The control unit can identify missed seeding events and re-seeding events by analyzing the time difference and quantity relationship of the pulse signals generated by the first photoelectric sensor and the second photoelectric sensor triggered by the same seed, and count the number of occurrences of the two types of events.

[0012] A further step involves calculating the sowing quality deviation value as follows: Count the number of missed and replay events occurring per unit time within a preset time window; Based on the real-time rotation speed of the scoop wheel and the number of seed scoops on the scoop wheel, the current theoretical seeding frequency is calculated; according to the theoretical seeding frequency and the time window, the total theoretical seeding number within the time window is determined, and then the missed seeding rate and the reseeding rate are calculated; where the missed seeding rate is the ratio of the number of missed seeding events to the total theoretical seeding number, and the reseeding rate is the ratio of the number of reseeding events to the total theoretical seeding number. via E (t) =Reseeding rate - Missed seeding rate, and the comprehensive seeding quality deviation value is calculated.

[0013] A further proposed approach involves the following process for generating target control commands: The sowing quality deviation value E (t) Input a preset incremental PID controller and calculate the feedback angle compensation amount ∆. f The calculation formula is as follows: ∆ f =K p ×[E (t) -E (t-1) ]+K i ×E (t) +K d ×[E (t) -2E (t-1) +E (t-2) ]; Among them, K p ,K i ,K d These are preset control parameters; The feedforward angle θ of the partition ff Compensation amount ∆ for feedback angle f Adding them together, we get the final target partition angle θ. target =θ ff +∆ f The final target partition angle is sent to the execution unit as the target control command.

[0014] In a further embodiment, the execution unit also includes: an arc-shaped guide rail, a motor mounting plate, and at least two rolling bearings; The arc-shaped guide rail and the arc-shaped rack are fixedly installed on the rear shell of the seed metering device with the same center. The motor mounting plate forms a sliding pair with the arc-shaped guide rail through at least two rolling bearings; The stepper motor is fixedly mounted on the motor mounting plate.

[0015] A further proposed solution includes an extended handle and a copper sleeve in the transmission mechanism; One end of the extended handle is fixedly connected to the partition, and the other end is provided with a mounting hole; The copper sleeve is press-fitted into the mounting hole; The gear's drive shaft passes through and is fixedly fitted with the copper sleeve, allowing the rotational motion of the drive shaft to be transmitted to the extended handle via the copper sleeve, which in turn converts it into the rotation of the partition plate around the center of the spoon wheel.

[0016] A further proposed solution involves the following steps in the operation of the control unit: A theoretical motion model of the seed on the spoon wheel is preset, which is used to describe the theoretical motion L. theory The functional relationship between the partition angle θ and the angular velocity ω of the scoop wheel: ; Based on the current partition angle θ k With real-time angular velocity ω of the spoon wheel k Calculate the current theoretical distance ; Based on the signal from the seed quality sensor module, the actual average seed travel distance L is estimated by inversion. actual,k Specifically, based on the seed transit time difference ΔT detected by the first and second photoelectric sensors in the seeding quality sensing module and the known sensor spacing d, the seed velocity seed = d / ΔT is estimated. Then, the actual average travel distance L per unit time is obtained by mapping through a pre-stored calibration relationship. actual,k .

[0017] Through the formula: The travel tracking error e is calculated. k ; With the goal of minimizing future prediction errors, a constrained optimization problem is solved based on a model predictive control algorithm to obtain the optimal baffle angle increment Δθ that minimizes the objective function. * The specific expression is: J= +λ×(Δθ) 2 ; Where λ is the weighting coefficient, the solution must satisfy θ min ≤θ k +Δθ≤θ max Mechanical constraints; The optimal partition angle increment Δθ * As a target control command, drive the partition to rotate to the target angle θ. k +Δθ * .

[0018] A further proposed approach is to express the theoretical motion range model f(θ,ω) as follows: ; Where R is the radius of the scoop wheel, A(θ) is a fixed stroke component function determined by the geometry of the partition and the structural parameters of the scoop wheel, u is the equivalent friction coefficient, g is the gravitational acceleration, and B(θ) is a dynamic component function describing the centrifugal seed cleaning effect and seed movement characteristics.

[0019] The beneficial effects of this invention are: (1) By constructing a closed-loop control system based on real-time seeding quality feedback, this invention realizes the adaptive dynamic adjustment of the partition angle, effectively solving the long-standing technical problem that fixed or manually adjustable partitions cannot adapt to complex dynamic working conditions in the field, resulting in difficulty in balancing missed seeding and reseeding.

[0020] (2) This invention solves the problems of adjustment lag, slow response speed and easy overshoot oscillation caused by the large inertia and nonlinearity of the system caused by a single feedback control by adopting a composite control strategy that combines fast coarse adjustment with fine adjustment by sowing quality feedback. This improves the dynamic response performance and control stability of the system.

[0021] (3) This invention solves the problems of mechanical redundancy, large transmission error, mismatch of motion trajectory and poor environmental adaptability of general linear actuators or ordinary rotary mechanisms when applied to partition adjustment by designing a special actuator with gear arc rack transmission and the center of the circle coincides with the center of the spoon wheel, and deeply couples it with the above control algorithm. It realizes efficient, accurate and reliable conversion of control commands to physical actions. Attached Figure Description

[0022] The invention will now be further described with reference to the accompanying drawings.

[0023] Figure 1 This is a flowchart of the method in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the overall structure of the spoon wheel seed metering device in this invention; Figure 3 for Figure 2 Schematic diagram of the structure of the outward-extending handle; Figure 4 for Figure 2 Schematic diagram of the transmission mechanism; Figure 5 for Figure 2 Schematic diagram of the structure of the seed guide tube; Figure 6 for Figure 2 A schematic diagram showing the positions of the rolling bearing and the arc-shaped guide rail; Figure 7 This is a schematic diagram showing the position of the magnet piece; Figure 8 This is a schematic diagram showing the location of the Hall sensor.

[0024] Figure Descriptions: 1. Seed guide wheel; 2. Rear shell of seed metering device; 3. Partition plate; 4. Spoon wheel; 5. Stepper motor; 6. Extended handle; 7. Gear; 8. Arc-shaped rack; 9. Fixing screw hole; 10. Seed guide tube; 11. First receiver; 12. Second receiver; 13. Second photoelectric sensor; 14. First photoelectric sensor; 15. Shaft hole; 16. Copper sleeve; 18. Motor fixing plate; 19. Rolling bearing; 20. Arc-shaped guide rail; 21. Screw hole; 23. Drive shaft; 24. Key; 25. Bolt; 26. Nut; 27. Support frame; 29. ​​Magnet piece; 30. Hall sensor. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] This invention is based on a spoon-wheel seed metering device. Specifically, the spoon-wheel seed metering device has a large C-shaped partition 3. By adjusting the angle of the partition 3, the position of the tail end of the partition 3 can be changed, thereby adjusting the entire seed transport stroke. This achieves the purpose of shortening or lengthening the seed transport stroke, thus changing the time that the seeds are exposed to strong centrifugal force. When the stroke is extended, the centrifugal force can be increased to throw out excess seeds, i.e., replanted seeds, for more time, reducing the replanting rate. When the stroke is shortened, the time that a single qualified seed is exposed to strong centrifugal force can be reduced, reducing the probability of accidental seed detachment, i.e., missed seed planting. Overall, by rotating the partition 3, the actual angular position of the seeding point on the circumference is moved, thereby continuously and accurately changing the arc length of the effective stroke.

[0027] Please see Figures 1-8 As shown, this invention relates to an automatic adjustment system for the partition of a spoon-wheel type seed metering device. Example 1 includes:

[0028] The detection feedback unit includes a rotation speed sensing module and a sowing quality sensing module. The rotation speed sensing module is used to detect the rotation speed of the scoop wheel in real time, and the sowing quality sensing module is used to detect the seed flow status through the seed metering tube 10 in real time and provide feedback on the sowing quality. The rotation speed sensing module includes a magnet 29 fixed to the periphery of the scoop wheel disk 4 and a Hall sensor 30 fixed to the rear shell of the seed metering device. The rotation speed of the scoop wheel is determined by detecting the pulse signal generated by the periodic passing of the magnet 29.

[0029] The execution unit includes a stepper motor 5, a gear 7 driven by the stepper motor 5, an arc-shaped rack 8 meshing with the gear 7, and a transmission mechanism for connecting and driving the partition 3; the arc-shaped rack 8 is fixedly installed on the rear shell of the seed metering device, and the center of the arc of the tooth profile of the arc-shaped rack 8 coincides with the center of the spoon wheel. The control unit calculates the angle of the target partition 3 based on the signals from the speed sensing module and the seeding quality sensing module, and drives the stepper motor 5 to rotate the partition 3 around the center of the spoon wheel to the target angle via the gear 7 and the arc rack 8.

[0030] The working process of the control unit is as follows: Based on the real-time detected rotational speed n of the spoon wheel by the rotational speed sensing module, the corresponding feedforward angle θ of the partition 3 is obtained by querying the preset reference angle lookup table for the rotational speed of the spoon wheel partition 3. ff ; Based on the signal from the sowing quality sensing module, the sowing quality deviation value is calculated. By combining the feedforward angle of partition 3 with the seeding quality deviation value, a target control command is generated to adjust partition 3 to the target angle. Drive stepper motor 5 according to the target control command.

[0031] The seeding quality sensing module consists of a first photoelectric sensor 14 and a second photoelectric sensor 13 arranged sequentially up and down along the direction of seed fall. The control unit can identify missed seeding events and replay events by analyzing the time difference and quantity relationship of the pulse signals generated by the first photoelectric sensor 14 and the second photoelectric sensor 13 triggered by the same seed, and count the number of occurrences of the two types of events.

[0032] The process of calculating the sowing quality deviation value is as follows: Count the number of missed and replay events occurring per unit time within a preset time window; Based on the real-time rotation speed of the scoop wheel and the number of seed scoops on the scoop wheel, the current theoretical seeding frequency is calculated; according to the theoretical seeding frequency and the time window, the total theoretical seeding number within the time window is determined, and then the missed seeding rate and the reseeding rate are calculated; where the missed seeding rate is the ratio of the number of missed seeding events to the total theoretical seeding number, and the reseeding rate is the ratio of the number of reseeding events to the total theoretical seeding number. via E (t) =Reseeding rate - Missed seeding rate, and the comprehensive seeding quality deviation value is calculated.

[0033] The process of generating target control instructions is as follows: The sowing quality deviation value E (t) Input a preset incremental PID controller and calculate the feedback angle compensation amount ∆. f The calculation formula is as follows: ∆ f =Kp ×[E (t) -E (t-1) ]+K i ×E (t) +K d ×[E (t) -2E (t-1) +E (t-2) ]; Among them, K p ,K i ,K d These are preset control parameters; The feedforward angle θ of the partition ff Compensation amount ∆ for feedback angle f Adding them together, we get the final target partition angle θ. target =θ ff +∆ f The final target partition angle is sent to the execution unit as the target control command.

[0034] The execution unit also includes: an arc-shaped guide rail 20, a motor mounting plate 18, and at least two rolling bearings 19; The arc-shaped guide rail 20 and the arc-shaped rack 8 are fixedly installed on the rear shell 2 of the seed metering device with the same center. The motor mounting plate 18 forms a sliding pair with the arc-shaped guide rail 20 through at least two rolling bearings 19; The stepper motor 5 is fixedly mounted on the motor mounting plate 18.

[0035] The transmission mechanism includes an extended handle 6 and a copper sleeve 16; One end of the extended handle 6 is fixedly connected to the partition 3, and the other end is provided with a mounting hole; The copper sleeve 16 is press-fitted into the mounting hole; The drive shaft 23 of gear 7 passes through the copper sleeve 16 and is fixedly engaged with the copper sleeve 16, so that the rotational motion of the drive shaft 23 is transmitted to the extended handle 6 through the copper sleeve 16, and then converted into the rotation of the partition 3 around the center of the spoon wheel.

[0036] In this embodiment, the overall workflow is as follows: Step 1: When the spoon-wheel seed metering device starts operating, the power-driven seed guide wheel 1 rotates. At this time, the automatic adjustment system is powered on and started; the microcontroller loads preset control parameters, including PID coefficients (K... p ,K i ,K d The system includes a speed and angle feedforward lookup table, and threshold parameters for missed / replay. Each sensor (speed sensor, dual photoelectric sensor) begins self-testing and enters continuous monitoring mode.

[0037] The second step involves the magnet 29 fixed on the scoop wheel 4 rotating with the scoop wheel and periodically passing through the Hall sensor 30 fixed on the rear shell 2 of the seed metering device. The sensor generates a pulse signal proportional to the rotational speed. The microcontroller receives this pulse signal in real time and accurately calculates the instantaneous rotational speed n of the scoop wheel (in rpm). Subsequently, the microcontroller accesses the internally stored reference angle mapping table of the rotational speed partition 3. This table, calibrated through numerous experiments, describes the approximate angle of the partition 3 required to achieve optimal seed cleaning effect at different rotational speeds. Simultaneously, seeds are fed from the seed box into the seed-collecting scoop of the rotating scoop wheel. The relative position between the scoop wheel and the partition 3 determines the seed's transport distance. The initial angle of the partition 3 can be manually preset via its extended handle 6.

[0038] The microcontroller looks up a table based on the current rotational speed n to obtain a basic target angle θ. ff For example, when n=50rpm, θ is obtained by looking up the table. ff =15°. The microcontroller immediately converts this angle value into the corresponding number of stepper motor pulses and direction commands, and sends them to the motor driver.

[0039] After receiving the command, the stepper motor 5 rotates rapidly, driving the transmission shaft 23 and gear 7 to rotate via key 24. Gear 7 meshes with a fixed arc-shaped rack 8. Since the arc-shaped rack 8 is fastened to the seed metering device rear housing 2 by bolts 25 through the fixing screw hole 9 on it, and the center of its tooth profile arc is precisely designed to coincide with the center of the scoop wheel, when gear 7 rotates, it does not rotate in place, but is forced to roll in a circle along the arc-shaped rack 8. To support and guide this rolling motion, an arc-shaped guide rail 20 is provided. The arc-shaped rack 8 and the arc-shaped guide rail 20 are fixed together to the rear housing 2 of the seed metering device through screw holes 21. A motor mounting plate 18 sits on the arc-shaped guide rail 20 via four rolling bearings 19, forming a low-friction sliding pair. The stepper motor 5 is securely mounted on this mounting plate. Therefore, the circumferential rolling motion of the gear 7 is converted into the smooth sliding of the entire motor assembly (including the stepper motor 5, the motor mounting plate 18, and the gear 7) along the arc-shaped guide rail 20.

[0040] One end of the drive shaft 23 engages with the shaft hole 15 on the extended handle 6 via a copper sleeve 16. When the drive shaft 23 undergoes a spatial attitude change due to the sliding of the motor assembly, it pushes the extended handle 6 through the copper sleeve 16, ultimately causing the partition 3 to rotate to a 15° position. This step is completed in a very short time after the seeding operation speed changes (such as tractor acceleration), achieving rapid pre-compensation for the main disturbance (change in centrifugal force).

[0041] Third, after the seeds are discharged from the scoop wheel, they fall through the seed guide tube 10. Below the outlet of the seed guide tube 10, the first photoelectric sensor 14 and its corresponding first receiver 11 are fixed by the support frame 27. 12cm below it, the second photoelectric sensor 13 and its second receiver 12 are also fixed. When the seeds pass through, they will block the two sensors in turn, generating two pulse signals with a definite time relationship.

[0042] The microcontroller analyzes these pulse signals in real time. Under normal conditions, a seed triggers two sensors sequentially, generating a standard time difference ΔT. When multiple seeds are too close together or fall simultaneously, the sensor signals may overlap or the time difference may be abnormally short. The system will identify this as a re-seeding event. If neither sensor has a valid trigger signal at the expected seeding time, the system will identify this as a missed seeding event.

[0043] The microcontroller counts the number of missed events N at a fixed period (e.g., per second). miss and the number of replay events N multi By combining the current scoop wheel speed and the number of seed-taking scoops to calculate the theoretical number of seed rows, the real-time missed seeding rate P is obtained. miss and replay rate P multi Then, the overall deviation value E is calculated. (t) =P multi -P miss The value E (t) The sign and magnitude of the value quantitatively reflect the current angle of the partition 3 as E. (t) >0, too small, leading to replays being the primary mode of playback or E. (t) <0 indicates that a value that is too high is the main reason for missed broadcasts.

[0044] Step 4: The microcontroller calculates the overall deviation value E. (t) Input incremental PID controller. The controller is based on E... (t) The current value, historical value, and trend of change are calculated according to the formula: ∆ f =K p ×[E (t) -E (t-1) ]+K i ×E (t) +K d ×[E (t) -2E (t-1) +E (t-2) The calculation is performed, and a precise angle compensation amount ∆ is output. f This compensation amount may be only a few degrees or even less, and its purpose is to refine the position after coarse feedforward adjustment. The microcontroller will use the feedforward base angle θ ff With feedback compensation amount ∆ f Perform algebraic superposition to generate the final target angle command θ. target =θff +∆ f .

[0045] The control unit drives the stepper motor 5 again. The stepper motor 5 drives the drive shaft 23 and gear 7 to rotate slightly via key 24. Since gear 7 meshes with the fixed arc-shaped rack 8, this slight rotation is converted into a small sliding displacement of the motor assembly on the arc-shaped guide rail 20. This displacement is transmitted to the extended handle 6 through the drive shaft 23 and the cooperating copper sleeve 16, ultimately causing a precise adjustment of the angle of the partition 3. Bolts 25 and nuts 26 are used to lock the connection between the fixing plate and the bearing, ensuring that the entire drive chain remains rigid after adjustment.

[0046] Fifth, steps two through four above are not executed sequentially once and then end, but are continuously repeated at a very high frequency (such as every 100 milliseconds) throughout the entire sowing process.

[0047] The speed sensor continuously monitors the speed, and the feedforward channel responds immediately to any speed change, readjusting the speed.

[0048] The dual photoelectric sensors continuously count, and the feedback channel continuously calculates the latest seeding quality deviation E(t).

[0049] The PID controller continuously outputs fine-tuning instructions based on the latest E(t) value.

[0050] Through the above cycle, in a constantly changing operating environment (speed, vibration, seed characteristics), the system dynamically searches for and locks onto the factor that minimizes the missed seeding rate P. miss and replay rate P multi At the same time, it is reduced to the lowest optimal partition angle of 3; even if external conditions are disturbed, it can quickly return to a stable state through rapid adjustment, thereby maintaining a high-precision and uniform seeding effect throughout the entire operation.

[0051] This embodiment uses a coarse adjustment based on rotational speed feedforward and a fine adjustment based on incremental PID feedback for seeding quality as the core control strategy. The rotational speed of the spoon wheel is detected in real time by Hall sensor 30, and the feedforward reference angle of the partition 3 is obtained from a table to achieve rapid pre-compensation. Dual photoelectric sensors arranged along the seed descent direction are used to detect the seed flow status, identify and count missed and reseeded events, and calculate the comprehensive seeding quality deviation value E. (t) The feedback angle compensation amount is calculated by incremental PID algorithm, and the feedforward angle and the compensation amount are superimposed to obtain the target partition 3 angle. Through a dedicated actuator consisting of stepper motor 5, gear 7, and arc rack 8 (the center of which coincides with the center of the spoon wheel), the partition 3 is driven to rotate precisely around the center of the spoon wheel. The entire adjustment process is carried out in a high-frequency closed-loop cycle to achieve adaptive dynamic adjustment of the partition 3 angle.

[0052] Through the above technical solutions, on the one hand, the speed feedforward channel performs real-time coarse adjustment of the scoop wheel speed change. When the seeder's operating speed changes abruptly (such as when a tractor accelerates / decelerates), it can adjust the baffle to an approximate angle suitable for the speed in a very short time, completing rapid pre-compensation for changes in centrifugal force. This avoids the problem of untimely adjustment caused by the large inertia and large lag of single feedback control. On the other hand, based on the precise detection of dual photoelectric sensors, the missed seeding rate and reseeding rate can be directly obtained and the comprehensive deviation can be calculated. The incremental PID algorithm can output fine compensation based on the current value, historical value and changing trend of the deviation, performing micro-adjustment of the three angles of the baffle. This solves the technical problem of the mutual constraint between missed seeding and reseeding in traditional systems and the inability to automatically find the optimal solution, achieving a dynamic balance between the two. Meanwhile, the actuator employs a gear 7 meshing with a concentric arc-shaped rack 8 for transmission, coupled with an arc-shaped guide rail 20 and a rolling bearing 19 for guidance. This converts the rotational motion of the stepper motor 5 into pure rotation of the partition 3 around the center of the spoon wheel, eliminating the mechanical redundancy and transmission errors of general linear actuators. The conversion from control commands to physical actions is highly efficient and precise, and the adjustment accuracy of the partition angle 3 can reach several degrees or even smaller. Finally, the entire adjustment process requires no manual intervention, cycling at a high frequency of 100 milliseconds. It can adapt to complex dynamic conditions such as operating speed, ground vibration, and seed characteristics in real time, solving the problems of fixed / manual partition 3 adjustment requiring machine stoppage and reliance on operator experience, and adapting to high-speed, high-precision sowing requirements. Furthermore, dual photoelectric sensors directly detect the seed flow status within the seed guide tube 10. Compared to traditional detection methods that rely on indirect parameters such as vibration and sound, this can directly and accurately identify missed sowing and re-sowing events, providing real and reliable sowing quality data support for partition angle adjustment. Example 2:

[0053] The working process of the control unit includes: A theoretical motion model of the seed on the spoon wheel is preset, which is used to describe the theoretical motion L. theory The functional relationship between the partition angle θ and the angular velocity ω of the scoop wheel: ; Based on the current partition angle θ k With real-time angular velocity ω of the spoon wheel k Calculate the current theoretical distance ; Based on the signal from the seed quality sensor module, the actual average seed travel distance L is estimated by inversion. actual,k Specifically, based on the seed transit time difference ΔT detected by the first and second photoelectric sensors in the seeding quality sensing module and the known sensor spacing d, the seed velocity seed = d / ΔT is estimated. Then, the actual average travel distance L per unit time is obtained by mapping through a pre-stored calibration relationship. actual,k .

[0054] Through the formula: The travel tracking error e is calculated. k ; With the goal of minimizing future prediction errors, a constrained optimization problem is solved based on a model predictive control algorithm to obtain the optimal baffle angle increment Δθ that minimizes the objective function. * The specific expression is: J= +λ×(Δθ) 2 ; Where λ is the weighting coefficient, the solution must satisfy θ min ≤θ k +Δθ≤θ max Mechanical constraints; Δθ is the angular change (in degrees) to be optimized at time k for adjusting the angle of partition 3, i.e., the change in the angle of partition 3 from the current angle θ. k The change value adjusted to the new angle; The smaller the value of J, the better the corresponding Δθ, which can minimize the prediction error of the future movement of the seed and minimize the adjustment of the partition angle. This represents the seed motion range prediction and tracking error at time k+1; that is, based on the current working condition data at time k (current partition angle θ). k Real-time angular velocity ω of the spoon wheel k Current travel tracking error e k The difference between the theoretical seed movement distance and the actual seed movement distance at the next sampling time (k+1) predicted by the seed theory movement distance model; the weight coefficient λ is a positive constant (dimensionless) calibrated in advance through field experiments, and is the core parameter for balancing the prediction error cost term and the angle increment regularization term in the objective function; Model predictive control, as a forward-looking control algorithm, does not compensate for errors that have already occurred, but rather adjusts the baffle angle in advance by predicting future errors, while simultaneously using λ×(Δθ). 2 The limitation on the adjustment range not only solves the lag of single feedback control, but also avoids the mechanical instability of unconstrained adjustment, making it suitable for the complex dynamic conditions of field sowing.

[0055] The optimal partition angle increment Δθ * As a target control command, drive the partition to rotate to the target angle θ. k +Δθ * .

[0056] A further proposed approach is to express the theoretical motion range model f(θ,ω) as follows: ; Where R is the radius of the scoop wheel, A(θ) is a fixed stroke component function determined by the geometry of the partition and the structural parameters of the scoop wheel, u is the equivalent friction coefficient, g is the gravitational acceleration, and B(θ) is a dynamic component function describing the centrifugal seed cleaning effect and seed movement characteristics.

[0057] In this embodiment, the optimal adjustment of the partition angle is achieved by using a model predictive control algorithm based on the theoretical motion path model of the seed. First, the theoretical motion path model of the seed on the spoon wheel is preset. The actual average distance L of seed movement was obtained by inverting the time difference of seed detection using dual photoelectric sensors. actual,k Calculate travel tracking error The objective is to minimize the future prediction error, and to solve for θ with mechanical constraints. min ≤θ k +Δθ≤θ max The optimization problem yields the optimal baffle angle increment Δθ. * The drive actuator rotates the partition to the target angle θ. k +Δθ * This enables proactive and optimal regulation based on seed movement trajectory.

[0058] The above scheme achieves two main advantages. First, it models the movement of seeds based on their inherent nature, resulting in more scientific and precise regulation. It breaks through the post-hoc compensation logic of Example 1, which relies on seed quality deviation. Instead, it establishes a mathematical model based on the seed's movement on the scoop wheel and the centrifugal seed-cleaning effect, directly linking the partition angle to the actual seed movement state. This fundamentally controls seed quality and reduces tracking errors. Second, model predictive control predicts and optimizes future tracking errors, providing the optimal partition angle adjustment in advance. Compared to the post-hoc feedback of PID controllers, this is more suitable for the nonlinear, time-varying, and large-lag dynamics of the scoop wheel seed meterer. It exhibits no overshoot or oscillation when operating speed changes frequently or seed characteristics (size, specific gravity) change, significantly improving regulation stability. Furthermore, when solving for the optimal angle increment, a mechanical limit constraint (θ) on the partition angle is added. min θ maxThis design avoids mechanical collisions between the partition and the scoop wheel / seed metering device rear shell due to over-adjustment, while also preventing a sudden drop in sowing quality caused by the partition angle exceeding the effective adjustment range, thus achieving a safe fit between the control algorithm and the mechanical structure. Finally, in the theoretical motion stroke model, the dynamic component function B(θ) can be calibrated according to the centrifugal seed-cleaning effect and motion characteristics of different seeds (corn, soybeans, peanuts, etc.). Only the model parameters need to be updated to adapt to the sowing needs of different medium and large-sized seeds, solving the problem of poor adaptability to seed characteristics in traditional adjustment systems. Furthermore, by precisely controlling the seed transport stroke on the scoop wheel by adjusting the partition angle 3, the centrifugal force's seed-cleaning effect on excess seeds and the effect of preventing single-seed loss are optimally balanced, ensuring thorough seed cleaning while preventing the accidental loss of qualified seeds. This is suitable for demanding conditions such as high-speed sowing (scoop wheel speed ≥ 100 rpm).

[0059] Specific examples: For precision seeding operations in soybean and peanut rotation plots, the seeder needs to continuously complete the sowing of both soybean and peanut seeds. The scoop wheel seed metering device has a scoop wheel radius of 12cm, an equivalent coefficient of friction u=0.3, and a gravitational acceleration g=9.8m / s². 2 Mechanical constraint θ of the partition angle min =8°, θ max =30°.

[0060] Soybean planting stage: The system loads soybean-specific travel model parameters; A(θ) is a fixed stroke function related to the partition angle, and B(θ) is the appropriate soybean particle size (5-8 mm, specific gravity 0.78 g / cm³). 3 The dynamic component function; Real-time angular velocity ω of the scoop wheel during seeder operation k =8rad / s; Current partition angle θ k =18°, substituting into the model, we obtain the theoretical stroke L. theory =25.6cm.

[0061] The dual photoelectric sensors detected a time difference ΔT = 0.08s for the soybean to pass through the sensors. The sensor spacing d = 12cm, and the seed velocity v = 150cm / s was calculated. The actual average travel distance L was obtained by mapping through calibration. actual,k =27.2cm, travel tracking error e k =25.6-27.2=-1.6cm (actual travel is greater than theoretical travel, which can easily lead to missed seeding).

[0062] The system aims to minimize future prediction errors by solving the optimization problem J= of model predictive control. +λ×(Δθ) 2The weighting coefficient λ = 0.05; The optimal angle increment Δθ is obtained by combining mechanical constraints. * =-1.5°; Target angle θ target =18°-1.5°=16.5°, the stepper motor 5 drives the partition 3 to complete the adjustment.

[0063] Switching to the peanut planting stage: Simply update the peanut-specific model parameters in the system, namely, peanut particle size of 10-15mm and specific gravity of 0.85g / cm³. 3 The corresponding B(θ) parameter can be adjusted without modifying the hardware structure; At this moment, the angular velocity of the spoon wheel is ω k =7 rad / s, current partition angle θ k =16.5∘, the theoretical travel distance L is calculated. theory =23.4cm, actual stroke L retrieved by dual photoelectric sensors actual,k =22.1cm, travel tracking error e k =1.3cm (actual travel is less than theoretical travel, which may lead to replay); the optimal angle increment Δθ is obtained by model predictive control. * =+1.2°, the partition is adjusted to 17.7° to achieve the optimal match between seed cleaning effect and seed shedding prevention effect.

[0064] It should be noted that the calculation formulas and all parameters involved in the calculations in this invention have been dimensionless beforehand. The process of dimensionless processing is well known in the industry and will not be described here.

[0065] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. An automatic adjustment system for the partition of a spoon-wheel type seed metering device, characterized in that, include: The detection feedback unit includes a rotation speed sensing module and a seeding quality sensing module. The rotation speed sensing module is used to detect the rotation speed of the spoon wheel in real time, and the seeding quality sensing module is used to detect the seed flow status through the seed metering tube in real time and provide feedback on the seeding quality. The execution unit includes a stepper motor, a gear driven by the stepper motor, an arc-shaped rack meshing with the gear, and a transmission mechanism for connecting and driving the partition; the arc-shaped rack is fixedly installed on the rear housing of the seed meterer, and the center of the arc of the tooth profile of the arc-shaped rack coincides with the center of the spoon wheel; The control unit calculates the target partition angle based on the signals from the speed sensor module and the seeding quality sensor module, and drives the stepper motor to rotate the partition around the center of the spoon wheel to the target angle through gear and rack transmission.

2. The automatic adjustment system for the partition of the spoon-wheel seed metering device according to claim 1, characterized in that, The working process of the control unit is as follows: Based on the real-time detected rotational speed n of the spoon wheel by the rotational speed sensing module, the corresponding feedforward angle θ of the partition is obtained by querying the preset reference angle lookup table for the rotational speed of the spoon wheel partition. ff ; Based on the signal from the sowing quality sensing module, the sowing quality deviation value is calculated. By combining the feedforward angle of the partition plate with the seeding quality deviation value, a target control command is generated to adjust the partition plate to the target angle. Drive the stepper motor according to the target control command.

3. The automatic adjustment system for the partition of the spoon-wheel seed metering device according to claim 2, characterized in that, The seeding quality sensing module consists of a first photoelectric sensor and a second photoelectric sensor arranged sequentially up and down along the direction of seed fall. The control unit can identify missed seeding events and re-seeding events by analyzing the time difference and quantity relationship of the pulse signals generated by the first photoelectric sensor and the second photoelectric sensor triggered by the same seed, and count the number of occurrences of the two types of events.

4. The automatic adjustment system for the partition of the spoon-wheel seed metering device according to claim 3, characterized in that, The process of calculating the sowing quality deviation value is as follows: Count the number of missed and replay events occurring per unit time within a preset time window; Based on the real-time rotation speed of the scoop wheel and the number of seed scoops on the scoop wheel, the current theoretical seeding frequency is calculated; according to the theoretical seeding frequency and the time window, the total theoretical seeding number within the time window is determined, and then the missed seeding rate and the reseeding rate are calculated; where the missed seeding rate is the ratio of the number of missed seeding events to the total theoretical seeding number, and the reseeding rate is the ratio of the number of reseeding events to the total theoretical seeding number. via E (t) =Reseeding rate - Missed seeding rate, and the comprehensive seeding quality deviation value is calculated.

5. The automatic adjustment system for the partition of the spoon-wheel seed metering device according to claim 2, characterized in that, The process of generating target control instructions is as follows: The sowing quality deviation value E (t) Input a preset incremental PID controller and calculate the feedback angle compensation amount ∆. f The calculation formula is as follows: ∆ f =K p ×[E (t) -E (t-1) ]+K i ×E (t) +K d ×[E (t) -2E (t-1) +E (t-2) ]; Among them, K p ,K i ,K d These are preset control parameters; The feedforward angle θ of the partition ff Compensation amount ∆ for feedback angle f Adding them together, we get the final target partition angle θ. target =θ ff +∆ f The final target partition angle is sent to the execution unit as the target control command.

6. The automatic adjustment system for the partition of the spoon-wheel seed metering device according to claim 5, characterized in that, The actuator also includes: an arc-shaped guide rail, a motor mounting plate, and at least two rolling bearings; The arc-shaped guide rail and the arc-shaped rack are fixedly installed on the rear shell of the seed metering device with the same center. The motor mounting plate forms a sliding pair with the arc-shaped guide rail through at least two rolling bearings; The stepper motor is fixedly mounted on the motor mounting plate.

7. The automatic adjustment system for the partition of the spoon-wheel seed metering device according to claim 1, characterized in that, The transmission mechanism includes an extended handle and a copper sleeve; One end of the extended handle is fixedly connected to the partition, and the other end is provided with a mounting hole; The copper sleeve is press-fitted into the mounting hole; The gear's drive shaft passes through and is fixedly fitted with the copper sleeve, allowing the rotational motion of the drive shaft to be transmitted to the extended handle via the copper sleeve, which in turn converts it into the rotation of the partition plate around the center of the spoon wheel.

8. The automatic adjustment system for the partition of the spoon-wheel seed metering device according to claim 1, characterized in that, The working process of the control unit includes: A theoretical motion model of the seed on the spoon wheel is preset, which is used to describe the theoretical motion L. theory The functional relationship between the partition angle θ and the angular velocity ω of the scoop wheel: ; Based on the current partition angle θ k With real-time angular velocity ω of the spoon wheel k Calculate the current theoretical distance ; Based on the signal from the seed quality sensor module, the actual average seed travel distance L is estimated by inversion. actual,k ; Through the formula: The travel tracking error e is calculated. k ; With the goal of minimizing future prediction errors, a constrained optimization problem is solved based on a model predictive control algorithm to obtain the optimal baffle angle increment Δθ that minimizes the objective function. * The specific expression is: J= +λ×(Δθ) 2 ; Where λ is the weighting coefficient, the solution must satisfy θ min ≤θ k +Δθ≤θ max Mechanical constraints; The optimal partition angle increment Δθ * As a target control command, drive the partition to rotate to the target angle θ. k +Δθ * .

9. The automatic adjustment system for the partition of the spoon-wheel seed metering device according to claim 8, characterized in that, The specific expression for the theoretical motion range model f(θ,ω) is as follows: ； Where R is the radius of the scoop wheel, A(θ) is a fixed stroke component function determined by the geometry of the partition and the structural parameters of the scoop wheel, u is the equivalent friction coefficient, g is the gravitational acceleration, and B(θ) is a dynamic component function describing the centrifugal seed cleaning effect and seed movement characteristics.

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