A seeding unit with a dynamic depth limiting function and an intelligent control method thereof

Abstract

The application discloses a seeding unit with a dynamic depth-limiting function and an intelligent control method thereof, wherein the seeding unit comprises a rack, a cleaning wheel group, a furrowing wheel group and a covering wheel group arranged from front to back on the rack; the furrowing wheel group is provided with a depth-limiting wheel on the left side and the right side respectively, the depth-limiting wheel is connected with the rack through a wheel frame, and the wheel frame is rotatably installed relative to the rack; a dynamic adjusting mechanism is connected between the wheel frame and the rack; the dynamic adjusting mechanism comprises a pull rod connected with the wheel frame, a cam rotatably installed on the rack and a servo motor for driving the cam to rotate; the dynamic adjusting mechanism further comprises a connecting frame rotatably connected with the pull rod, and the relative rotation shafts of the two are perpendicular to the left-right direction; a roller in contact with the profile of the cam is installed on the connecting frame, and the connecting frame is provided with a guide groove, and the central shaft of the cam is arranged in the guide groove; the application further comprises a ground data acquisition unit, and the ground data acquisition unit and the servo motor are connected with a controller.

Description

Technical Field

[0001] This invention relates to the field of agricultural sowing technology, and in particular to a sowing unit with dynamic depth adjustment function and its intelligent control method. Background Technology

[0002] In mechanized agricultural seeding operations, seeding depth is a key factor affecting crop emergence rate and uniformity of growth. To control furrowing depth, existing seeders are typically equipped with depth-limiting wheels, which are installed on the side of the furrow opener and limit the depth of the furrow opener's penetration into the soil through contact with the ground. In actual operations, especially when dealing with undulating terrain or fields where conservation tillage (no-till, reduced tillage) is practiced, the surface is often covered with straw or stubble of varying thickness. Traditional passive contour-following depth-limiting mechanisms struggle to ensure that seeds fall to a consistent depth into firm soil.

[0003] In the current technology, patent CN113179711A discloses a trenching, seeding, and soil-covering device, which uses a first adjusting mechanism to mount a depth-limiting wheel on a machine base. In this prior art, the first adjusting mechanism mainly includes an adjusting screw, an adjusting nut seat, and a first rotating frame. The user rotates the adjusting screw, driving the adjusting nut seat to move, which in turn rotates the first rotating frame, thereby setting the height of the depth-limiting wheel relative to the machine base to limit the trenching depth. This screw-nut adjustment method is a static manual adjustment, which cannot change the depth limit height in real time according to terrain conditions during operation. This results in the inability to adaptively adjust the trenching depth when facing complex terrain. Furthermore, the harsh working environment in farmland makes the threaded joint structure of the screw and nut prone to jamming, wear, or even seizing due to dust accumulation, rust, or mud intrusion, affecting the reliability and service life of the adjustment. More importantly, most existing depth-limiting wheels are wide rubber wheels that press directly onto the surface cover (such as straw) or uneven loose soil to perform contouring. They are easily affected by straw and loose soil. This passive contouring method, which relies solely on the depth-limiting wheel, cannot perceive the actual location of the seedbed under the cover and cannot meet the requirements of high-speed and high-precision agronomy. Summary of the Invention

[0004] Purpose of the invention: In order to overcome the shortcomings of the existing technology, the present invention provides a seeding unit with dynamic depth control function and intelligent control method, which has a highly reliable dynamic adjustment mechanism and can perform intelligent feedforward control based on the real soil reference surface.

[0005] Technical Solution: To achieve the above objectives, the present invention provides a seeding unit with dynamically adjustable depth limiting function, comprising a frame on which a cleaning wheel assembly, a furrowing wheel assembly, and a soil covering wheel assembly are mounted from front to back; the furrowing wheel assembly has depth limiting wheels on its left and right sides, the depth limiting wheels being connected to the frame via wheel frames, the wheel frames being rotatably mounted relative to the frame; the cleaning wheel assembly is elastically floating relative to the frame, and the outer edge of the cleaning wheel has multiple teeth arranged in a circumferential array;

[0006] A dynamic adjustment mechanism is connected between the wheel frame and the machine frame. The dynamic adjustment mechanism includes a pull rod connected to the wheel frame, a cam rotatably mounted on the machine frame, and a servo motor driving the cam to rotate. The dynamic adjustment mechanism also includes a connecting frame rotatably connected to the pull rod, with their relative axes of rotation perpendicular to the left and right directions. A roller that contacts the profile of the cam is mounted on the connecting frame, and the connecting frame has a guide groove. The central axis of the cam is placed in the guide groove. When the servo motor rotates, the connecting frame can pull the pull rod under the combined action of the guide groove and the cam, causing the wheel frame to rotate and thus adjusting the height of the depth-limiting wheel. The cam is a disc cam, with the roller and pull rod placed on both sides of the cam. In this way, the rotation of the cam can effectively extend and retract the pull rod.

[0007] It also includes a ground data acquisition unit, and both the ground data acquisition unit and the servo motor are connected to the controller.

[0008] Furthermore, the guide groove is an open groove, which facilitates disassembly and assembly.

[0009] Furthermore, the data acquired by the ground data acquisition unit can reflect the relative height between the cleaning wheel and the frame.

[0010] Furthermore, the wheel frame of the cleaning wheel assembly is rotatably mounted relative to the frame, and a telescopic elastic mechanism is connected between the frame and the wheel frame. The two ends of the telescopic elastic mechanism are respectively hinged to the wheel frame and the frame; the ground data acquisition unit is a displacement sensor, and its two ends are respectively connected to the two hinged ends of the telescopic elastic mechanism.

[0011] The intelligent control method based on the above-mentioned seeding unit with dynamic depth adjustment function includes:

[0012] The structural parameters of the seeding unit are preset in the controller, including the distance L between the cleaning wheel axis and the furrowing wheel axis in the front-to-back direction, and the nonlinear mapping function f(θ) between the rotation angle θ of the cam and the vertical displacement ΔH of the depth limiting wheel relative to the frame.

[0013] The forward speed v of the seeding unit is acquired in real time, and the real-time fluctuation data h0(t) of the cleaning wheel relative to the frame is collected by the ground data acquisition unit at a preset sampling frequency.

[0014] Feature extraction is performed on the collected real-time fluctuation data h0(t) to obtain an effective reference signal h(t);

[0015] The lag time Δt = L / v for the trenching wheel group to reach the current position of the cleaning wheel is calculated based on the spacing L and the forward speed v; and the effective reference signal h(t) corresponding to the current time t is used as the target adjustment reference for the depth limiting wheel at time t+Δt.

[0016] According to the preset target sowing depth H t The target vertical compensation amount ΔH is calculated based on the target adjustment reference. t The target angle θ of the cam is then calculated based on the nonlinear mapping function f(θ). t =f -1 (ΔH t );

[0017] According to the target angle θ t The target rotation angle of the servo motor is calculated based on the current angle of the cam and the reduction ratio between the motor shaft and the cam, and the servo motor is controlled to rotate to that angle at time t+Δt.

[0018] Further, the step of extracting features from the collected real-time fluctuation data h0(t) to obtain an effective reference signal h(t) includes:

[0019] Set a time sliding window W that is dynamically adjusted with speed v; the time period of the time sliding window W shall at least cover the time required for the cleaning wheel to rotate between the tooth pitches of the two teeth.

[0020] The effective reference signal h0(t) collected within the sliding window W is subjected to extreme value screening to identify a set of local maxima points where the cleaning wheel is furthest from the frame.

[0021] Calculate the average value of the data in the set of maximum points, compare each data point with the average value, remove data whose difference from the average value is greater than a preset difference threshold, and use the effective data to perform interpolation fitting to generate the continuous effective reference signal h(t).

[0022] Beneficial effects: The sowing unit with dynamic depth adjustment function and its intelligent control method of the present invention have the following beneficial effects:

[0023] (1) The sowing unit with dynamic depth adjustment function in this invention, on the one hand, adopts a dynamic adjustment mechanism with servo motor driving cam and pull rod transmission, which has high responsiveness, and the contact transmission between cam and roller significantly improves the reliability of the mechanism under harsh working conditions. In contrast, the screw threads commonly used in the prior art are prone to jamming failure and wear problems in the dusty environment of farmland. On the other hand, the controller realizes dynamic adjustment of the height of the depth limiting wheel by combining ground data, which can accurately control the furrowing depth according to the ground data, ensuring that the furrowing depth of the furrowing wheel group is reasonable and ensuring the sowing quality.

[0024] (2) The connection structure between the connecting frame, the cam, and the pull rod is ingenious, ensuring effective cooperation and transmission relationship, and does not impose additional restrictions on the movement of the pull rod.

[0025] (3) The ground data acquisition unit can collect data that reflects the relative height of the cleaning wheel and the frame, and can reflect the height of the solid soil. Combined with the layout of the trenching wheel group that is slightly behind the depth limiting wheel in this invention, the depth limiting wheel can be adjusted in real time through the dynamic adjustment mechanism, so as to change the trenching depth in a timely manner to adapt to the terrain changes. Attached Figure Description

[0026] Figure 1 This is a side view of the structure of a seeding unit;

[0027] Figure 2 A three-dimensional structural diagram of a seeding unit;

[0028] Figure 3 for Figure 2 Enlarged structural diagram of section A;

[0029] Figure 4 This is a structural diagram of the cam section.

[0030] In the diagram: 1-Frame; 2-Cleaning wheel assembly; 21-Cleaning wheel; 21a-Toothed part; 22-Wheel frame; 23-Telescopic elastic mechanism; 3-Ditching wheel assembly; 4-Covering wheel assembly; 5-Depth limiting wheel; 6-Wheel frame; 7-Tie rod; 8-Cam; 8a-Central shaft; 9-Servo motor; 10-Connecting frame; 10a-Guide groove; 11-Roller; 12-Ground data acquisition unit; 13-Seed pressing wheel; 14-Seed feeding tube. Detailed Implementation

[0031] The invention will now be further described with reference to the accompanying drawings.

[0032] like Figure 1 and Figure 2The seeding unit shown includes a frame 1, on which a cleaning wheel assembly 2, a furrowing wheel assembly 3, and a soil covering wheel assembly 4 are mounted from front to back. The furrowing wheel assembly 3 has depth-limiting wheels 5 on its left and right sides, and the depth-limiting wheels 5 are connected to the frame 1 through wheel frames 6, which are rotatably mounted relative to the frame 1. The cleaning wheel assembly 2 can elastically float relative to the frame 1, and the outer edge of the cleaning wheel 21 has multiple teeth 21a arranged in a circumferential array.

[0033] A dynamic adjustment mechanism is connected between the wheel frame 6 and the frame 1; the dynamic adjustment mechanism includes a pull rod 7 connected to the wheel frame 6, a cam 8 rotatably mounted on the frame 1, and a servo motor 9 driving the cam 8 to rotate; the dynamic adjustment mechanism also includes a connecting frame 10 rotatably connected to the pull rod 7, the relative rotation axes of the two being perpendicular to the left and right directions; Figure 3 and Figure 4 As shown, a roller 11 is installed on the connecting frame 10, which contacts the profile of the cam 8, and the connecting frame 10 has a guide groove 10a. The central shaft 8a of the cam 8 is placed in the guide groove 10a. When the servo motor 9 rotates, the connecting frame 10 can pull the pull rod 7 under the combined action of the guide groove 10a and the cam 8, so that the wheel frame 6 rotates, thereby adjusting the height of the depth limiting wheel 5. The cam 8 is a disc cam, and the roller 11 and the pull rod 7 are placed on both sides of the cam 8. In this way, the rotation of the cam 8 can effectively extend and retract the pull rod 7.

[0034] It also includes a ground data acquisition unit 12, and both the ground data acquisition unit 12 and the servo motor 9 are connected to the controller.

[0035] In addition, there is a seed pressing wheel 13 between the two depth limiting wheels 5. Furthermore, the seeding unit also includes a seed feeding tube 14 placed between the two furrowing wheels of the furrowing wheel group 3. The seeds fed out by the seed feeding tube 14 are pressed down by the seed pressing wheel 13 in time to prevent the seeds from bouncing.

[0036] The sowing unit with dynamic depth adjustment function in this invention employs a dynamic adjustment mechanism using a servo motor 9 driving a cam 8 and transmitting power via a pull rod 7. This mechanism offers high responsiveness, and the contact transmission between the cam 8 and the roller 11 significantly improves the reliability of the mechanism under harsh working conditions. In contrast, the screw threads commonly used in existing technologies are prone to jamming, failure, and wear in dusty farmland environments. Furthermore, the controller dynamically adjusts the height of the depth-limiting wheel 5 based on ground data, enabling precise control of the furrowing depth and ensuring a reasonable furrowing depth for the furrowing wheel assembly 3, thus guaranteeing sowing quality.

[0037] The connection structure between the connecting frame 10, the cam 8, and the pull rod 7 is ingenious, ensuring effective cooperation and transmission without imposing additional restrictions on the movement of the pull rod 7.

[0038] Preferably, the guide groove 10a is an open groove, which facilitates disassembly and assembly.

[0039] Preferably, the data acquired by the ground data acquisition unit 12 can reflect the relative height between the cleaning wheel 21 and the frame 1.

[0040] Preferably, the wheel frame 22 of the cleaning wheel set 2 is rotatably mounted relative to the frame 1, and a telescopic elastic mechanism 23 is connected between the frame 1 and the wheel frame 22. The two ends of the telescopic elastic mechanism 23 are respectively hinged to the wheel frame 22 and the frame 1; the ground data acquisition unit 12 is a displacement sensor, and its two ends are respectively connected to the two hinged ends of the telescopic elastic mechanism 23.

[0041] During operation, the cleaning wheel 21 rotates actively, and the teeth 21a on its edge can not only clear weeds and stubble from the ground, but also penetrate deep into the loose soil, so that the teeth 21a of the cleaning wheel 21 can come into contact with the firm soil.

[0042] The ground data acquisition unit 12 can collect data that reflects the relative height between the cleaning wheel 21 and the frame 1, and can reflect the height of the solid soil. Combined with the layout of the trenching wheel group 3 being slightly rearward relative to the depth limiting wheel 5 in this invention, the depth limiting wheel 5 can be adjusted in real time through the dynamic adjustment mechanism, so as to change the trenching depth in a timely manner to adapt to the terrain changes.

[0043] The intelligent control method based on the above-mentioned seeding unit with dynamic depth adjustment function includes the following steps S1-S6:

[0044] Step S1: Preset the structural parameters of the seeding unit in the controller, including the distance L between the axis of the cleaning wheel 21 and the axis of the furrowing wheel group 3 in the front-to-back direction, and the nonlinear mapping function f(θ) between the rotation angle θ of the cam 8 and the vertical displacement ΔH of the depth limiting wheel 5 relative to the frame 1.

[0045] Step S2: The forward speed v of the seeding unit is acquired in real time, and the real-time fluctuation data h0(t) of the cleaning wheel 21 relative to the frame 1 is collected by the ground data acquisition unit 12 at a preset sampling frequency.

[0046] Step S3: Extract features from the collected real-time fluctuation data h0(t) to obtain an effective reference signal h(t);

[0047] Step S4: Calculate the lag time Δt=L / v of the trenching wheel group 3 reaching the current position of the cleaning wheel 21 based on the spacing L and the forward speed v; and use the effective reference signal h(t) corresponding to the current time t as the target adjustment reference of the depth limiting wheel 5 at time t+Δt.

[0048] Step S5, according to the preset target sowing depth H t The target vertical compensation amount ΔH is calculated based on the target adjustment reference. t The target angle θ of the cam 8 is calculated based on the nonlinear mapping function f(θ). t =f -1 (ΔH t );

[0049] Step S6, based on the target angle θ t The current angle of the cam 8 and the reduction ratio between the motor shaft and the cam 8 are used to calculate the target rotation angle of the servo motor 9, and the servo motor 9 is controlled to rotate to that angle at time t+Δt.

[0050] The intelligent control method establishes a lag model by using the distance and speed between the cleaning wheel 21 and the trenching wheel group 3. By calculating the lag time, it performs feedforward prediction and adjustment, which overcomes the response lag under high-speed operation and ensures that the adjustment action is aligned with the ground undulation. At the same time, it combines the nonlinear mapping relationship function fθ corresponding to the cam for inverse solution, which ensures the accuracy of trenching depth under complex terrain.

[0051] Preferably, the step S3 above, which involves extracting features from the collected real-time fluctuation data h0(t) to obtain an effective reference signal h(t), includes the following steps S31-S33:

[0052] Step S31: Set a time sliding window W that is dynamically adjusted with speed v; the time period of the time sliding window W shall at least cover the time required for the cleaning wheel 21 to rotate between the tooth pitch of the two teeth 21a.

[0053] Step S32: The effective reference signal h0(t) collected within the sliding window W is subjected to extreme value screening to identify a set of local maxima points where the cleaning wheel 21 is furthest from the frame 1.

[0054] Step S33: Calculate the average value of the data in the set of maximum points, compare each data with the average value, remove data whose difference from the average value is greater than a preset difference threshold, and use the effective data to perform interpolation fitting to generate the continuous effective reference signal h(t).

[0055] In response to the high-frequency oscillation characteristics of the toothed cleaning wheel 21 operating on straw-covered surfaces, by extracting local maxima and removing shallow abnormal data, false height noise caused by straw or soil clods can be effectively filtered out. The solid seedbed can be effectively used as the real reference surface. Combined with the continuous signal generated by interpolation fitting, the interference of surface residues on trenching depth is eliminated.

[0056] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A seeding unit with dynamic depth adjustment function, comprising a frame (1), wherein a cleaning wheel assembly (2), a furrowing wheel assembly (3), and a soil covering wheel assembly (4) are mounted on the frame (1) from front to back; the furrowing wheel assembly (3) has depth limiting wheels (5) on its left and right sides respectively, the depth limiting wheels (5) being connected to the frame (1) via wheel frames (6), the wheel frames (6) being rotatably mounted relative to the frame (1); the cleaning wheel assembly (2) is elastically floating relative to the frame (1), and the outer edge of the cleaning wheel (21) therein has a plurality of teeth (21a) arranged in a circumferential array; characterized in that: A dynamic adjustment mechanism is connected between the wheel frame (6) and the frame (1); the dynamic adjustment mechanism includes a pull rod (7) connected to the wheel frame (6), a cam (8) rotatably mounted on the frame (1), and a servo motor (9) driving the cam (8) to rotate; the dynamic adjustment mechanism also includes a connecting frame (10) rotatably connected to the pull rod (7), the relative rotation axes of the two being perpendicular to the left and right directions; a roller (11) that contacts the profile of the cam (8) is mounted on the connecting frame (10), and the connecting frame (10) has a guide groove (10a), the central shaft (8a) of the cam (8) is placed in the guide groove (10a); It also includes a ground data acquisition unit (12), and both the ground data acquisition unit (12) and the servo motor (9) are connected to the controller.

2. The seeding unit with dynamic depth adjustment function according to claim 1, characterized in that, The guide groove (10a) is an open groove.

3. The seeding unit with dynamic depth adjustment function according to claim 1, characterized in that, The data acquired by the ground data acquisition unit (12) can reflect the relative height between the cleaning wheel (21) and the frame (1).

4. The seeding unit with dynamic depth adjustment function according to claim 3, characterized in that, The wheel frame (22) of the cleaning wheel set (2) is rotatably mounted relative to the frame (1). A telescopic elastic mechanism (23) is connected between the frame (1) and the wheel frame (22). The two ends of the telescopic elastic mechanism (23) are respectively hinged to the wheel frame (22) and the frame (1). The ground data acquisition unit (12) is a displacement sensor, and its two ends are respectively connected to the two hinged ends of the telescopic elastic mechanism (23).

5. The intelligent control method for a seeding unit with dynamic depth adjustment function as described in claim 3, characterized in that the method... include: The structural parameters of the seeding unit are preset in the controller, including the distance L between the axis of the cleaning wheel (21) and the axis of the furrowing wheel group (3) in the front-to-back direction, and the nonlinear mapping function f(θ) between the rotation angle θ of the cam (8) and the vertical displacement ΔH of the depth limiting wheel (5) relative to the frame (1). The forward speed v of the seeding unit is obtained in real time, and the real-time fluctuation data h0(t) of the cleaning wheel (21) relative to the frame (1) is collected by the ground data acquisition unit (12) at a preset sampling frequency; Feature extraction is performed on the collected real-time fluctuation data h0(t) to obtain an effective reference signal h(t); The lag time Δt = L / v of the trenching wheel group (3) reaching the current position of the cleaning wheel (21) is calculated based on the distance L and the forward speed v; and the effective reference signal h (t) corresponding to the current time t is used as the target adjustment reference of the depth limiting wheel (5) at time t+Δt. According to the preset target sowing depth H t The target vertical compensation amount ΔH is calculated based on the target adjustment reference. t And the target angle θ of the cam (8) is solved according to the nonlinear mapping function f(θ). t =f -1 (ΔH t ); According to the target angle θ t The current angle of the cam (8) and the reduction ratio between the motor shaft and the cam (8) are used to calculate the target rotation angle of the servo motor (9) and control the servo motor (9) to rotate to that angle at time t+Δt.

6. The intelligent control method according to claim 1, characterized in that, The step of extracting features from the collected real-time fluctuation data h0(t) to obtain an effective reference signal h(t) includes: Set a time sliding window W that dynamically adjusts with velocity v; The effective reference signal h0(t) collected within the sliding window W is subjected to extreme value screening to identify a set of local maxima points where the cleaning wheel (21) is furthest from the frame (1). Calculate the average value of the data in the set of maximum points, compare each data point with the average value, remove data whose difference from the average value is greater than a preset difference threshold, and use the effective data to perform interpolation fitting to generate the continuous effective reference signal h(t).

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