A wheat fertilization device and method based on closed-loop control

Abstract

This invention relates to a wheat fertilization device and method based on closed-loop control. The wheat fertilization device includes a frame and a fertilizer box, a counter-rotating double-helix fertilizer applicator, a fertilizer application monitoring device, a furrow opener, and a fertilizer application control system mounted on the frame. The counter-rotating double-helix fertilizer applicator includes a left fertilizer applicator shell, a right fertilizer applicator shell, a counter-rotating fertilizer application spiral, and a fertilizer application pipe. The frame includes a crossbeam, a fertilizer box mounting plate, a fertilizer box connecting plate, a fertilizer box support beam, a triangular fixing plate, a support beam plate, and a crossbeam sealing plate. The fertilizer furrow opener includes a furrow opener body, a reflective fertilizer application pipe, and a furrow opener plow head. The fertilizer application monitoring device includes a shell, a monitoring circuit board, a monitoring electrode plate, a differential electrode plate, a mounting bracket, a fertilizer application connecting pipe, and a wiring pipe. The fertilizer application control system includes an electrical control box, a controller, a stepper motor, a stepper motor driver, a sprocket, a implement attitude sensor, a speed measuring radar, a radar mounting bracket, and a motor bracket.

Description

Technical Field

[0001] This invention belongs to the field of agricultural machinery technology, and specifically relates to a wheat fertilization device and method based on closed-loop control. Background Technology

[0002] Fertilization is a crucial part of wheat cultivation, providing essential nutrients and directly impacting wheat yield and quality. Most current wheat fertilization devices employ open-loop control to regulate fertilizer application. For example, the "Wheat Row Seeder Control Device and Method" disclosed in Chinese invention patent application "CN116649050A" replaces traditional ground-wheel drive with electric drive to control fertilizer application. It obtains the motor's rotational speed through a rotary encoder mounted on the fertilizer discharge shaft, and uses a collaborative algorithm between the implement's travel speed and the motor's speed to indirectly regulate the fertilizer application by adjusting the motor speed. However, this method primarily controls motor speed, with the fertilizer application amount being a result of changes in motor speed. This can introduce errors into the accuracy of fertilization operations. Therefore, a method for direct regulation of fertilizer application is needed to achieve precise control. Summary of the Invention

[0003] To overcome the shortcomings of existing electronically controlled fertilization technology and the problem of uneven fertilizer discharge by fertilizer dispensers, the purpose of this invention is to provide a wheat fertilization device and method based on closed-loop control, which can use the amount of fertilizer applied as feedback input to control the amount of fertilizer discharged, and adjust the amount of fertilizer applied according to the machine's operating speed to achieve uniform and precise fertilization.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] A wheat fertilization device based on closed-loop control includes a frame 3 and a fertilizer box 1, a counter-rotating double helix fertilizer dispenser 2, a fertilizer application rate monitoring device 4, a furrow opener 5, and a fertilizer application rate control system 6 installed on the frame 3.

[0006] The fertilizer box 1 includes a front box panel 1-1, side panels 1-2, a rear box panel 1-5, a front inclined bottom panel 1-6, and a rear inclined bottom panel 1-7; the two side panels 1-2 are fixed to both sides of the front box panel 1-1 and the rear box panel 1-5; the front inclined bottom panel 1-6 and the rear inclined bottom panel 1-7 are fixed to the bottom ends of the front box panel 1-1, the rear box panel 1-5, and the two side panels 1-2, forming a funnel-shaped bottom; the bottom of the funnel-shaped box is provided with multiple pairs of fertilizer outlets 1-8 at equal intervals along the transverse direction of the machine.

[0007] Below each pair of fertilizer outlets 1-8, there is a counter-rotating double helix fertilizer discharger 2 fixed to the bottom of the funnel-shaped box.

[0008] The counter-rotating double-helix fertilizer discharger 2 includes a left fertilizer discharger shell 2-1, a right fertilizer discharger shell 2-2, a counter-rotating fertilizer discharge spiral 2-3, and a fertilizer discharge pipe 2-6. The left fertilizer discharger shell 2-1 and the right fertilizer discharger shell 2-2 are hollow cylindrical tubes. The right end of the left fertilizer discharger shell 2-1 and the left end of the right fertilizer discharger shell 2-2 are coaxially fixed to each other to form a fertilizer discharge chamber. The counter-rotating fertilizer discharge spiral 2-3 is disposed in the fertilizer discharge chamber. The counter-rotating fertilizer discharge spiral 2-3 is composed of two fertilizer discharge spirals with the same structural parameters but opposite rotation directions. The top of the left fertilizer discharger shell 2-1 and the top of the right fertilizer discharger shell 2-2 are both provided with fertilizer inlets 2-4 corresponding to fertilizer outlets 1-8. The bottom of the left fertilizer discharger shell 2-1 is provided with a fertilizer discharge port 2-5, which is located below the center of the counter-rotating fertilizer discharge spiral 2-3 and is connected to the fertilizer discharge pipe 2-6.

[0009] The frame 3 includes a crossbeam 3-1, a fertilizer tank mounting plate 3-2, a fertilizer tank connecting plate 3-3, a fertilizer tank support beam 3-4, a triangular fixing plate 3-5, a support beam support plate 3-6, and a crossbeam sealing plate 3-7; the crossbeam 3-1 is horizontally arranged below the fertilizer tank 1, with a crossbeam sealing plate 3-7 fixed to each end; a pair of fertilizer tank mounting plates 3-2 are fixed to the crossbeam 3-1; two triangular fixing plates 3-5 are fixed to the side plates 1-2 at the left and right ends of the fertilizer tank 1; the front inclined base plate 1 -6 and the rear inclined base plate 1-7 are each provided with a pair of supporting beams 3-6; two fertilizer box supporting beams 3-4 are arranged below the front inclined base plate 1-6 and the rear inclined base plate 1-7, and are fixedly connected to the triangular fixing plate 3-5 and the supporting beams 3-6; the fertilizer box mounting plate 3-2 is fixedly connected to the two fertilizer box supporting beams 3-4 through two fertilizer box connecting plates 3-3; multiple fertilizer applicators 5, which correspond one-to-one with the counter-rotating double helix fertilizer applicator 2, are fixedly connected to the crossbeam 3-1 for opening fertilizer trenches.

[0010] The fertilizer applicator 5 includes an applicator body 5-1, a reflective fertilizer applicator tube 5-3, and an applicator plow head 5-4; the applicator body 5-1 is fixedly connected to the crossbeam 3-1; the applicator plow head 5-4 is installed at the front bottom of the applicator body 5-1; the reflective fertilizer applicator tube 5-3 is fixedly connected to the rear end face of the applicator body 5-1, and the fertilizer inlet at the bottom of the reflective fertilizer applicator tube 5-3 is located at the rear bottom of the applicator body 5-1.

[0011] Each fertilizer applicator 5 has a fertilizer application monitoring device 4 installed between its reflective fertilizer application pipe 5-3 and the corresponding counter-rotating double helix fertilizer discharger 2's discharge pipe 2-6.

[0012] The fertilizer application monitoring device 4 includes a housing 4-1, a monitoring circuit board 4-2, a monitoring electrode plate 4-3, a differential electrode plate 4-4, a mounting bracket 4-5, a fertilizer discharge connecting pipe 4-6, and a wiring pipe 4-7.

[0013] The mounting bracket 4-5 is located inside the outer casing 4-1. The mounting bracket 4-5 consists of a rectangular connecting pipe bracket and a rectangular differential plate bracket fixed in parallel. Each rectangular connecting pipe bracket and rectangular differential plate bracket is composed of a top plate, a left side plate, a right side plate, and a bottom plate. The fertilizer discharge connecting pipe 4-6 vertically passes through the top and bottom plates of the rectangular connecting pipe bracket and the top and bottom plates of the outer casing 4-1. The top end of the fertilizer discharge connecting pipe 4-6 connects to the fertilizer discharge pipe 2-6 of the counter-rotating double-helix fertilizer discharger 2, and the bottom end connects to the reflective fertilizer discharge pipe of the fertilizer ditch opener 5. 5-3 Connection; The monitoring electrode 4-3 is fixedly connected to the front and rear faces of the rectangular connecting pipe bracket; The differential electrode 4-4 is fixedly connected to the inner walls of the left and right sides of the rectangular differential electrode bracket; The monitoring circuit board 4-2 is fixedly connected to the outer surface of the side plate of the rectangular connecting pipe bracket and is electrically connected to the monitoring electrode 4-3 and the differential electrode 4-4 respectively; The line tube 4-7 is set on the bottom plate of the outer casing 4-1, located below the monitoring circuit board 4-2, and is used to lead the line of the monitoring circuit board 4-2 to the fertilizer application control system 6.

[0014] The monitoring circuit board 4-2 includes an STM32F103C8T6 chip, an AD7745 chip, a TJA1050 chip, and an HT7833 chip. It provides stable power to the monitoring circuit board 4-2, collects and processes the capacitance values ​​measured by the monitoring plate 4-3 and the differential plate 4-4, and communicates with the fertilizer application control system 6. The monitoring circuit board 4-2 connects the capacitor plates of the monitoring plate 4-3 and the differential plate 4-4 in a differential mode. The first capacitor plate of the monitoring plate 4-3 and the first capacitor plate of the differential plate 4-4 are respectively connected to the EXCA excitation pin of the AD7745 chip. The second capacitor plate of monitoring plate 4-3 is connected to the CIN(+) pin of the AD7745 chip as a positive capacitor input; the second capacitor plate of differential plate 4-4 is connected to the CIN(-) pin of the AD7745 chip as a negative capacitor input; the 5V power supply input from the fertilizer application control system 6 is filtered by capacitors and powered by the HT7833 chip to the monitoring circuit board 4-2; the STM32F103C8T6 chip reads the data value measured by the AD7745 chip and converts it into a capacitance value; the capacitance value is then transmitted to the fertilizer application control system 6 via CAN communication through the TJA1050 chip.

[0015] The fertilizer application control system 6 includes an electrical control box 6-1, a controller 6-2, a stepper motor 6-3, a stepper motor driver 6-4, a sprocket 6-5, a machine attitude sensor 6-6, a speed measuring radar 6-7, a radar mounting bracket 6-8, and a motor bracket 6-9.

[0016] The electrical control box 6-1 is installed on the outer end face of the side plate 1-2 of the fertilizer tank 1. It houses a controller 6-2, an LCD screen, a stepper motor driver 6-4, a machine attitude sensor 6-6, and a PWM signal amplifier. The controller 6-2 is an STM32F407ZGT6 development board, connected to the LCD screen, PWM signal amplifier, stepper motor driver 6-4, machine attitude sensor 6-6, and speed radar 6-7. The stepper motor 6-3 is fixed to the triangular fixing plate 3-5 via a motor bracket 6-9. The power output shaft of the stepper motor 6-3 is connected to the fertilizer discharge shaft fixed to the end of the counter-rotating fertilizer discharge spiral 2-3 via a sprocket 6-5 and a chain. The stepper motor 6-3 is connected to the stepper motor driver 6-4, which is connected to the controller 6-2 via a PWM signal amplifier. The PWM signal amplifier can output a 3.3V PWM signal from the I / O port of the controller 6-2. The M-pulse signal is boosted to 5V, reaching the drive signal voltage range of the stepper motor driver 6-4; the implement posture sensor 6-6 is connected to the controller 6-2 to monitor the posture of the wheat fertilization device based on closed-loop control, including the raised idle state and the lowered working state; the speed measuring radar 6-7 is mounted on the outside of the crossbeam sealing plate 3-7 via the radar mounting bracket 6-8; the controller 6-2 communicates with the monitoring circuit board 4-2 in the fertilizer application monitoring device 4 through the CAN communication protocol to obtain the current actual fertilizer application, and communicates with the implement posture sensor 6-6 through the IIC communication protocol to obtain the current working status of the implement, and obtains the current forward speed of the implement by reading the square wave signal frequency fed back by the speed measuring radar 6-7; and adjusts the stepper motor speed by outputting PWM signals of different frequencies; the human-machine interface is displayed on the LCD screen.

[0017] Two box support plates 1-3 are provided between the front box plate 1-1 and the rear box plate 1-5 to stabilize the fertilizer box structure; at least two fertilizer outlets 1-4 are provided on the rear inclined bottom plate 1-7 for discharging the remaining fertilizer after the fertilization operation is completed.

[0018] The total length L of the counter-rotating fertilizer discharge spiral 2-3 is 300mm, the outer diameter D of the spiral blade is 55mm, the outer diameter d of the spiral shaft is 25mm, the spiral blade pitch S is 30mm, the tooth root radius r is 2mm, and the combined angle α of the two fertilizer discharge spirals is -148°; the length l of the fertilizer discharge port 2-5 at the bottom of the left fertilizer discharger shell 2-1 is 70mm.

[0019] The shaft end of the counter-rotating fertilizer discharge spiral 2-3 has a square cross-section and is connected to the square fertilizer discharge shaft as a power input.

[0020] The front end face of the furrow opener body 5-1 is provided with a guard plate 5-2, which is located above the furrow opener plow head 5-4.

[0021] The fertilizer box 1 is provided with six pairs of fertilizer outlets 1-8, and six counter-rotating double helix fertilizer dispensers 2 and six fertilizer ditch openers 5 are provided accordingly; the six counter-rotating double helix fertilizer dispensers 2 are arranged at equal intervals along the horizontal direction of the machine at the bottom of the fertilizer box 1; the interval between two adjacent fertilizer ditch openers 5 is 440mm.

[0022] The outer casing 4-1 is fixedly mounted on the upper end face of the crossbeam 3-1 by bolts. The outer casing 4-1 is made of metal. The monitoring electrode 4-3 and the differential electrode 4-4 are fixed to the mounting bracket 4-5 by glue. The mounting bracket 4-5 is made of steel plate. The bottom of the monitoring circuit board 4-2 is provided with an insulating layer and is fixed to the mounting bracket 4-5 by screws. The mounting bracket 4-5 is fixed to the outer casing 4-1 by bolts. The GND through hole on the monitoring circuit board 4-2 is grounded to the entire fertilizer application monitoring device 4 by screws.

[0023] The outer diameter of the fertilizer discharge connecting pipe 4-6 is 35mm; the monitoring electrode 4-3 consists of a pair of 50×100mm circuit boards (PCBs), with a copper-clad area of ​​40×90mm and a spacing of 40mm; the differential electrode 4-4 consists of a pair of 40×50mm circuit boards (PCBs), with a copper-clad area of ​​40×45mm and a spacing of 20mm; both the monitoring electrode 4-3 and the differential electrode 4-4 have a solder resist layer on the copper-clad side of their PCBs.

[0024] The speed measuring radar 6-7 is installed at a height of 40cm and at an angle of 35° to the ground.

[0025] A wheat fertilization regulation method utilizing the aforementioned closed-loop control-based wheat fertilization device includes the following steps:

[0026] S1. System initialization, setting fertilizer application rate per acre;

[0027] The controller 6-2 is initialized, and the fertilizer application monitoring device 4, the implement attitude sensor 6-6, the speed measuring radar 6-7 and the stepper motor 6-3 are started. The fertilizer application rate per mu is set through the human-machine interface.

[0028] S2. Determine the operating status of the wheat fertilization device;

[0029] When the machine posture sensor 6-6 detects that the wheat fertilizer is in a raised idle state, the stepper motor 6-3 is turned off, pausing the fertilization operation; when the machine posture sensor 6-6 detects that the wheat fertilizer is in a lowered working state, the stepper motor 6-3 is started, and the fertilization operation begins.

[0030] S3. Closed-loop control of fertilizer application rate;

[0031] The controller 6-2 adjusts the speed of the stepper motor 6-3 in a closed loop based on the machine's forward speed measured by the speed measuring radar 6-7, the set fertilizer application rate per acre, and the actual fertilizer application rate measured by the fertilizer application rate monitoring device.

[0032] S3.1 The fertilizer application monitoring device measures the actual fertilizer application rate at the current forward speed of the machine and transmits it to the controller 6-2;

[0033] Formula 1

[0034] Formula 2

[0035] Formula 3

[0036] In Formulas 1 to 3, DATA represents the actual measured value of the AD7745 chip during the fertilizer application monitoring process. is the dielectric constant of the vacuum medium, expressed in pF / mm; To monitor the volume of fertilizer in the space directly opposite electrode 4-3, to the unit mm 3 ;d 监测 The distance between the first capacitor plate and the second capacitor plate of electrode 4-3 is measured in mm. The relative permittivity of the fertilizer; is the relative permittivity of air; C is the capacitance value measured by the fertilizer application monitoring device, in pF; 0x800000 is a hexadecimal number, the midpoint of the chip's capacitance measurement range of -4pF to 4pF and the measured value of 0x000000 to 0xFFFFFF, equivalent to the decimal number 0; Q 实际 This represents the actual amount of fertilizer applied, expressed in g / s.

[0037] S3.2, Controller 6-2, combined with the set fertilizer application rate per mu, calculates the theoretical fertilizer application rate at the current machine forward speed according to Formula 4;

[0038] Formula 4

[0039] In formula 4, Q 理论 The theoretical fertilizer application rate at the current machine forward speed is expressed in g / s; M is the set fertilizer application rate per acre, expressed in kg; v is the forward speed of the machine, expressed in m / s; L is the working width of the machine, expressed in m; N is the number of counter-rotating double helix fertilizer applicators 2.

[0040] S3.3, Controller 6-2 compares the actual fertilizer application rate with the theoretical fertilizer application rate at the current machine forward speed. If the actual fertilizer application rate does not match the theoretical fertilizer application rate, then the speed of stepper motor 6-3 is controlled by PID according to formula 5.

[0041] Formula 5

[0042] In Formula 5, n is the stepper motor speed, in r / min; Q n This represents the fertilizer application rate when the stepper motor speed is n, expressed in g / s.

[0043] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0044] 1. The present invention provides a wheat fertilization device based on closed-loop control, which adjusts the fertilization amount in real time through a counter-rotating double helix fertilizer dispenser, a fertilizer amount monitoring device based on a capacitive sensor, and a fertilizer amount control system based on closed-loop control. This realizes that the measured actual fertilizer amount is used as feedback input to the control system to adjust the fertilizer amount, avoiding the reduction of fertilization accuracy and labor intensity caused by the fertilizer amount control system composed of motor speed closed-loop control, and improving the work efficiency.

[0045] 2. The counter-rotating double helix fertilizer applicator of the present invention is configured with two fertilizer applicator spiral blades with the same structural parameters but opposite rotation directions to form a counter-rotating fertilizer applicator spiral. This can compensate for the fertilizer application fluctuation effect caused by a single fertilizer applicator spiral, so that fertilizer particles are evenly discharged from the fertilizer applicator and the utilization rate of fertilizer resources is improved.

[0046] 3. The fertilizer application monitoring device based on capacitive sensors of the present invention uses differential mode to measure fertilizer application, which can resist the influence of external environment such as temperature changes, operation vibration, electromagnetic interference, etc., and improve the accuracy of fertilizer application measurement; moreover, the device has high accuracy and sensitive response in measuring fertilizer application, and is suitable for monitoring different types of fertilizers.

[0047] 4. The fertilizer application control system based on closed-loop control of this invention achieves intelligent and automated operation through electronic control technology. By collecting information such as machine speed and posture measured by sensors, the actual fertilizer application data measured by the fertilizer application monitoring device is transmitted as feedback data to the controller. The controller combines the sensor measurement data and the actual fertilizer application data, and uses PID control to adjust the stepper motor speed in real time, achieving uniform and precise fertilization. This fertilizer application control system adjusts the fertilizer application rate in real time by measuring the falling fertilizer amount, realizing closed-loop control of fertilizer application rate adjustment. Attached Figure Description

[0048] Figure 1 This is a schematic diagram of the overall structure of the wheat fertilization device based on closed-loop control according to the present invention.

[0049] Figure 2 This is a top view schematic diagram of the wheat fertilization device based on closed-loop control according to the present invention;

[0050] Figure 3This is a front view schematic diagram of the wheat fertilization device based on closed-loop control according to the present invention.

[0051] Figure 4a This is a schematic diagram of the left-side structure of the wheat fertilization device based on closed-loop control according to the present invention;

[0052] Figure 4b This is a schematic diagram of the left-side structure of the wheat fertilization device based on closed-loop control according to the present invention;

[0053] Figure 5 A schematic diagram of the overall structure of the counter-rotating double-helix fertilizer applicator 4;

[0054] Figure 6a This is a schematic diagram of a counter-rotating fertilizer discharge spiral.

[0055] Figure 6b This is a schematic diagram of a counter-rotating fertilizer discharge spiral.

[0056] Figure 7 A schematic diagram of the overall structure and internal structure of the fertilizer application monitoring device;

[0057] Figure 8 A schematic diagram of the circuit connection for monitoring circuit board 4-2;

[0058] Figure 9 This is a diagram of the stepper motor PID control scheme for the wheat fertilization device based on closed-loop regulation according to the present invention.

[0059] Figure 10 This is a system flowchart of the wheat fertilization device based on closed-loop control according to the present invention.

[0060] The reference numerals in the attached figures are:

[0061] 1-1. Front box panel 1-2, Side panels 1-3. Box support plate 1-4, Yufeikou 1-5. Rear box panel 1-6. Forward tilted base plate 1-7. Rear-sloping base plate 1-8. Fertilizer outlet 2. Counter-rotating double helix fertilizer applicator 2-1. Left-side fertilizer container casing 2-2, Right-side fertilizer container casing 2-3. Counter-rotating fertilizer discharge spiral 2-4. Fertilizer Inlet 2-5. Fertilizer discharge outlet 2-6. Fertilizer discharge pipe 3. Rack 3-1, Crossbeam 3-2. Fertilizer tank mounting plate 3-3. Fertilizer box connecting plate 3-4. Fertilizer box support beam 3-5. Triangular fixing plate 3-6. Support plate for beam 3-7. Beam sealing plate 4. Fertilizer application monitoring device 4-1. Outer shell 4-2 Monitoring Circuit Board 4-3. Monitoring plates 4-4. Differential plates 4-5. Install the bracket 4-6. Fertilizer discharge connecting pipe 4-7. Conduit for wiring 5. Fertilizer trencher 5-1. Main body of the trencher 5-2, Protective Plate 5-3. Reflective Fertilizer Application Pipe 5-4. Furrow opener plow head 6. Fertilizer application control system 6-1 Electrical control box 6-2, Controller 6-3. Stepper Motor 6-4. Stepper motor driver 6-5, Sprocket 6-6. Machine attitude sensor 6-7. Speed ​​measuring radar 6-8. Radar mounting bracket 6-9. Motor bracket Detailed Implementation

[0062] The present invention will be further described below with reference to the accompanying drawings and examples.

[0063] like Figure 1 As shown, a wheat fertilization device based on closed-loop control according to the present invention includes a frame 3 and a fertilizer box 1, a counter-rotating double helix fertilizer dispenser 2, a fertilizer application monitoring device 4, a furrow opener 5, and a fertilizer application control system 6 based on closed-loop control, all installed on the frame 3.

[0064] like Figure 2As shown, the fertilizer box 1 includes a front box plate 1-1, side plates 1-2, box support plates 1-3, excess fertilizer inlets 1-4, a rear box plate 1-5, a front inclined bottom plate 1-6, a rear inclined bottom plate 1-7, and a fertilizer outlet 1-8; the two side plates 1-2 are fixed to the two sides of the front box plate 1-1 and the rear box plate 1-5; the front inclined bottom plate 1-6 and the rear inclined bottom plate 1-7 are fixed to the bottom ends of the front box plate 1-1, the rear box plate 1-5, and the two side plates 1-2, forming a funnel-shaped bottom of the box; the two box support plates 1-3 are fixed between the front box plate 1-1 and the rear box plate 1-5 by bolts, so that the fertilizer box structure is stable; the bottom of the funnel-shaped box is provided with multiple pairs of fertilizer outlets 1-8 at equal intervals along the transverse direction of the machine; the rear inclined bottom plate 1-7 is provided with at least two excess fertilizer inlets 1-4 for discharging excess fertilizer after the fertilization operation is completed.

[0065] like Figure 1 and Figure 3 As shown, a counter-rotating double helix fertilizer dispenser 2, which is fixed to the bottom of the funnel-shaped box, is installed below each pair of fertilizer outlets 1-8.

[0066] like Figure 5 As shown, the counter-rotating double-helix fertilizer discharger 2 includes a left fertilizer discharger shell 2-1, a right fertilizer discharger shell 2-2, a counter-rotating fertilizer discharge spiral 2-3, a fertilizer inlet 2-4, a fertilizer outlet 2-5, and a fertilizer discharge pipe 2-6; the left fertilizer discharger shell 2-1 and the right fertilizer discharger shell 2-2 are hollow cylindrical tubes; the right end of the left fertilizer discharger shell 2-1 and the left end of the right fertilizer discharger shell 2-2 are coaxially connected to each other by bolts to form a fertilizer discharge chamber; the counter-rotating fertilizer discharge spiral 2-3... 3. Set in the fertilizer discharge chamber; the counter-rotating fertilizer discharge spiral 2-3 is composed of two fertilizer discharge spirals with the same structural parameters but opposite rotation directions; the top of the left fertilizer discharger shell 2-1 and the top of the right fertilizer discharger shell 2-2 are both provided with fertilizer inlets 2-4 corresponding to the fertilizer outlet 1-8; the bottom of the left fertilizer discharger shell 2-1 is provided with a fertilizer discharge port 2-5, which is located below the center of the counter-rotating fertilizer discharge spiral 2-3 and is connected to the fertilizer discharge pipe 2-6.

[0067] Traditional single-spiral fertilizer applicators, due to their unique structural design, inevitably experience flow fluctuations, resulting in poor fertilizer uniformity. Therefore, this invention adds a counter-rotating fertilizer applicator spiral with identical structural parameters but opposite rotation direction. This counter-rotating spiral compensates for the fertilizer application fluctuations caused by the single spiral, improving the fertilizer uniformity of the applicator.

[0068] The fertilizer discharge performance of the spiral fertilizer dispenser was analyzed using discrete element method (DEM) simulation, and the structural parameters of the counter-rotating double spiral fertilizer dispenser were optimized. For example... Figure 6a and Figure 6bAs shown, the total length L of the counter-rotating fertilizer discharge spiral 2-3 is 300mm, the outer diameter D of the spiral blades is 55mm, the outer diameter d of the spiral shaft is 25mm, the spiral blade pitch S is 30mm, the tooth root fillet radius r is 2mm, and the combined angle α of the two fertilizer discharge spiral sections is -148°. Figure 5 As shown, the length l of the fertilizer outlet 2-5 at the bottom of the left fertilizer outlet shell 2-1 is 70mm.

[0069] Preferably, the shaft end cross-section of the counter-rotating fertilizer discharge spiral 2-3 is square, and it is connected to the square fertilizer discharge shaft as a power input.

[0070] like Figure 3 and Figure 4b As shown, the frame 3 includes a crossbeam 3-1, a fertilizer box mounting plate 3-2, a fertilizer box connecting plate 3-3, a fertilizer box support beam 3-4, a triangular fixing plate 3-5, a support beam plate 3-6, and a crossbeam sealing plate 3-7. The crossbeam 3-1 is horizontally arranged below the fertilizer box 1, with a crossbeam sealing plate 3-7 fixed to each end. A pair of fertilizer box mounting plates 3-2 are fixed to the crossbeam 3-1. Two triangular fixing plates 3-5 are fixed to the side plates 1-2 at the left and right ends of the fertilizer box 1. A pair of support beam plates 3-6 are provided on both the front inclined base plate 1-6 and the rear inclined base plate 1-7. Two fertilizer box support beams 3-4 are arranged below the front inclined base plate 1-6 and the rear inclined base plate 1-7, and are fixed to the triangular fixing plate 3-5 and the support beam plate 3-6. The fertilizer box mounting plate 3-2 is fixed to the two fertilizer box support beams 3-4 through two fertilizer box connecting plates 3-3. Multiple fertilizer applicators 5, each corresponding to the counter-rotating double helix fertilizer applicator 2, are fixed to the crossbeam 3-1 and used to open fertilizer furrows.

[0071] like Figure 4a and Figure 4b As shown, the fertilizer applicator 5 includes an applicator body 5-1, a reflective fertilizer applicator tube 5-3, and an applicator plow head 5-4; the applicator body 5-1 is fixedly connected to the crossbeam 3-1; the applicator plow head 5-4 is installed at the front bottom of the applicator body 5-1 by bolts; the reflective fertilizer applicator tube 5-3 is fixedly connected to the rear end face of the applicator body 5-1, and the fertilizer inlet at the bottom end of the reflective fertilizer applicator tube 5-3 is located at the rear bottom of the applicator body 5-1.

[0072] Preferably, a guard plate 5-2 is provided on the front end face of the furrow opener body 5-1, and the guard plate 5-2 is located above the furrow opener plow head 5-4.

[0073] In this embodiment of the invention, the fertilizer box 1 is provided with six pairs of fertilizer outlets 1-8, corresponding to six counter-rotating double-helix fertilizer dispensers 2 and six fertilizer applicator 5; wherein, the six counter-rotating double-helix fertilizer dispensers 2 are arranged at equal intervals along the transverse direction of the machine at the bottom of the fertilizer box 1. The interval between two adjacent fertilizer applicators 5 is 440mm.

[0074] Each fertilizer applicator 5 has a fertilizer application monitoring device 4 installed between its reflective fertilizer application pipe 5-3 and the corresponding counter-rotating double helix fertilizer discharger 2's discharge pipe 2-6.

[0075] like Figure 7 As shown, the fertilizer application monitoring device 4 includes a housing 4-1, a monitoring circuit board 4-2, a monitoring electrode plate 4-3, a differential electrode plate 4-4, a mounting bracket 4-5, a fertilizer discharge connecting pipe 4-6, and a wiring pipe 4-7.

[0076] The mounting bracket 4-5 is located inside the outer casing 4-1. The mounting bracket 4-5 consists of a rectangular connecting pipe bracket and a rectangular differential plate bracket fixed in parallel. Each rectangular connecting pipe bracket and rectangular differential plate bracket is composed of a top plate, a left side plate, a right side plate, and a bottom plate. The fertilizer discharge connecting pipe 4-6 vertically passes through the top and bottom plates of the rectangular connecting pipe bracket and the top and bottom plates of the outer casing 4-1. The top end of the fertilizer discharge connecting pipe 4-6 connects to the fertilizer discharge pipe 2-6 of the counter-rotating double-helix fertilizer discharger 2, and the bottom end connects to the reflective fertilizer discharge pipe of the fertilizer ditch opener 5. 5-3 Connection; The monitoring electrode 4-3 is fixedly connected to the front and rear faces of the rectangular connecting pipe bracket; The differential electrode 4-4 is fixedly connected to the inner walls of the left and right sides of the rectangular differential electrode bracket; The monitoring circuit board 4-2 is fixedly connected to the outer surface of the side plate of the rectangular connecting pipe bracket and is electrically connected to the monitoring electrode 4-3 and the differential electrode 4-4 respectively; The line tube 4-7 is set on the bottom plate of the outer casing 4-1, located below the monitoring circuit board 4-2, and is used to lead the line of the monitoring circuit board 4-2 to the fertilizer application control system 6.

[0077] The outer casing 4-1 is bolted to the upper end of the crossbeam 3-1, and the fertilizer discharge connecting pipe 4-6 is installed vertically to reduce monitoring errors caused by fertilizer collisions. The outer casing 4-1 is made of metal, which can shield external signals and reduce the impact of electromagnetic interference on fertilizer application measurement. The monitoring electrode 4-3 and the differential electrode 4-4 are fixed to the mounting bracket 4-5 with glue; to reduce mutual interference between the monitoring electrode 4-3 and the differential electrode 4-4 when monitoring fertilizer application, the mounting bracket 4-5 is made of steel plate.

[0078] The bottom of the monitoring circuit board 4-2 is provided with an insulating layer and is fixed to the mounting bracket 4-5 by screws. The mounting bracket 4-5 is fixed to the outer shell 4-1 by bolts. The GND through hole on the monitoring circuit board 4-2 is grounded with the entire fertilizer application monitoring device 4 by screws, which enhances the anti-interference ability and avoids vibration inside the fertilizer application monitoring device 4 during the fertilization operation.

[0079] like Figure 8As shown, the monitoring circuit board 4-2 includes an STM32F103C8T6 chip, an AD7745 chip, a TJA1050 chip, and an HT7833 chip. It provides stable power to the monitoring circuit board 4-2, collects and processes the capacitance values ​​measured by the monitoring plate 4-3 and the differential plate 4-4, and communicates with the fertilizer application control system 6. The monitoring circuit board 4-2 connects the capacitor plates of the monitoring plate 4-3 and the differential plate 4-4 in a differential mode. The first capacitor plate of the monitoring plate 4-3 and the differential plate 4-4... The first capacitor plate of the differential plate 4-4 is connected to the EXCA excitation pin of the AD7745 chip; the second capacitor plate of the monitoring plate 4-3 is connected to the CIN(+) pin of the AD7745 chip as a positive capacitor input; the second capacitor plate of the differential plate 4-4 is connected to the CIN(-) pin of the AD7745 chip as a negative capacitor input. Using differential mode to measure fertilizer application can suppress the influence of ambient temperature changes, power fluctuations, and electromagnetic interference on capacitance measurement, and can improve measurement sensitivity. The 5V power supply input from the fertilizer application control system 6 powers the monitoring circuit board 4-2 through capacitor filtering and the HT7833 chip. The STM32F103C8T6 chip reads the data value measured by the AD7745 chip and converts it into a capacitance value. The capacitance value is then transmitted to the fertilizer application control system 6 via CAN communication through the TJA1050 chip.

[0080] In this embodiment of the invention, the outer diameter of the fertilizer discharge connecting pipe 4-6 is 35mm. The monitoring electrode 4-3 consists of a pair of 50×100mm PCBs, with a copper-clad area of ​​40×90mm and a spacing of 40mm. The differential electrode 4-4 consists of a pair of 40×50mm PCBs, with a copper-clad area of ​​40×45mm and a spacing of 20mm. Solder resist layers are added to the copper-clad side of the PCBs of the monitoring electrode 4-3 and the differential electrode 4-4, respectively, which serve to insulate and protect the copper foil from oxidation, corrosion, and damage.

[0081] like Figure 4a As shown, the fertilizer application control system 6 based on closed-loop control includes an electrical control box 6-1, a controller 6-2, a stepper motor 6-3, a stepper motor driver 6-4, a sprocket 6-5, a machine attitude sensor 6-6, a speed measuring radar 6-7, a radar mounting bracket 6-8, and a motor bracket 6-9.

[0082] The electrical control box 6-1 is installed on the outer end face of the side plate 1-2 of the fat box 1. It houses a controller 6-2, an LCD screen, a stepper motor driver 6-4, a machine attitude sensor 6-6, and a PWM signal amplifier. The controller 6-2 is an STM32F407ZGT6 development board, connected to the LCD screen, PWM signal amplifier, stepper motor driver 6-4, machine attitude sensor 6-6, and speed radar 6-7. The stepper motor 6-3 is fixed to the triangular fixing plate 3-5 via a motor bracket 6-9. The power output shaft of stepper motor 6-3 is connected to the fertilizer discharge shaft fixed to the end of the counter-rotating fertilizer discharge screw 2-3 via sprocket 6-5 and chain; stepper motor 6-3 is connected to stepper motor driver 6-4, which is connected to controller 6-2 via a PWM signal amplifier. The PWM signal amplifier can boost the 3.3V PWM pulse signal output from the I / O port of controller 6-2 to 5V, reaching the drive signal voltage range of stepper motor driver 6-4; the machine attitude sensor 6-6 is connected to controller 6-2. The system is used to monitor the posture of a wheat fertilization device based on closed-loop control. The posture of the wheat fertilization device based on closed-loop control includes a raised idle state and a lowered working state. The speed measuring radar 6-7 is mounted on the outside of the crossbeam sealing plate 3-7 via a radar mounting bracket 6-8 to reduce the impact of machine vibration on radar measurement. The installation height of the speed measuring radar 6-7 is 40cm, and the angle with the ground is 35°. Since the speed measuring radar 6-7 is very sensitive to any error in the angle with the ground, the angle between the speed measuring radar 6-7 and the ground can be adjusted via the radar mounting bracket 6-8 connected by bolts. The controller 6-2 communicates with the monitoring circuit board 4-2 in the fertilizer application monitoring device 4 through the CAN communication protocol to obtain the current actual fertilizer application amount, and communicates with the machine posture sensor 6-6 through the IIC communication protocol to obtain the current working status of the machine. It obtains the current forward speed of the machine by reading the square wave signal frequency fed back by the speed measuring radar 6-7, and adjusts the stepper motor speed by outputting PWM signals of different frequencies. The human-machine interface is displayed on the LCD screen.

[0083] like Figure 9 and Figure 10 As shown, a wheat fertilization regulation method using the aforementioned closed-loop control-based wheat fertilization device includes the following steps:

[0084] S1. System initialization, setting fertilizer application rate per acre;

[0085] The controller 6-2 is initialized, and the fertilizer application monitoring device 4, the implement attitude sensor 6-6, the speed measuring radar 6-7 and the stepper motor 6-3 are started. The fertilizer application rate per mu is set through the human-machine interface.

[0086] S2. Determine the operating status of the wheat fertilization device;

[0087] When the machine posture sensor 6-6 detects that the wheat fertilizer is in a raised idle state, the stepper motor 6-3 is turned off, pausing the fertilization operation; when the machine posture sensor 6-6 detects that the wheat fertilizer is in a lowered working state, the stepper motor 6-3 is started, and the fertilization operation begins.

[0088] S3. Closed-loop control of fertilizer application rate;

[0089] The controller 6-2 adjusts the speed of the stepper motor 6-3 in a closed loop based on the machine's forward speed measured by the speed measuring radar 6-7, the set fertilizer application rate per acre, and the actual fertilizer application rate measured by the fertilizer application rate monitoring device.

[0090] S3.1 The fertilizer application monitoring device measures the actual fertilizer application rate at the current forward speed of the machine and transmits it to the controller 6-2;

[0091] Formula 1

[0092] Formula 2

[0093] Formula 3

[0094] In Formulas 1 to 3, DATA represents the actual measured value of the AD7745 chip during the fertilizer application monitoring process. is the dielectric constant of the vacuum medium, expressed in pF / mm; To monitor the volume of fertilizer in the space directly opposite electrode 4-3, to the unit mm 3 ;d 监测 The distance between the first capacitor plate and the second capacitor plate of electrode 4-3 is measured in mm. The relative permittivity of the fertilizer; is the relative permittivity of air; C is the capacitance value measured by the fertilizer application monitoring device, in pF; 0x800000 is a hexadecimal number, the midpoint of the chip's capacitance measurement range of -4pF to 4pF and the measured value of 0x000000 to 0xFFFFFF, equivalent to the decimal number 0; Q 实际 This represents the actual amount of fertilizer applied, expressed in g / s.

[0095] Fertilizer falls from fertilizer tank 1 to the monitoring area of ​​fertilizer application monitoring device 4 under the action of counter-rotating double helix fertilizer dispenser 2. Under the same environmental conditions, the capacitance values ​​measured by monitoring plate 4-3 and differential plate 4-4 are equal, and the capacitance value measured by fertilizer application monitoring device 4 is the difference between the capacitance values ​​measured by monitoring plate 4-3 and differential plate 4-4. When fertilizer falls into the monitoring area of ​​fertilizer application monitoring device 4, the dielectric constant and dielectric constant between the first and second capacitor plates of monitoring plate 4-3 change, causing the capacitance value measured by monitoring plate 4-3 to change accordingly. At this time, the actual measurement value of the AD7745 chip during the fertilizer application monitoring process is calculated using formula 1; furthermore, the capacitance value of the fertilizer passing through the monitoring area can be calculated using formula 2. From formulas 1 and 2, it can be seen that when the monitoring plate is fixed in its installation position, i.e. When unchanged, , , Since the capacitance value remains constant, the capacitance value measured by the fertilizer application monitoring device 4 during fertilization is linearly related to the volume of fertilizer in the space directly opposite the monitoring plate. The fertilizer application monitoring device 4 uses a recursive averaging filter to remove noise or interference signals from the measured capacitance data, ensuring stable and reliable capacitance values. Bench tests are conducted to measure capacitance values ​​under different fertilizer application rates, and a mathematical model is established between the measured capacitance values ​​and the fertilizer application rate, i.e., Formula 3. Based on the established mathematical model, the actual fertilizer application rate at the current machine forward speed is obtained from the capacitance value measured by the fertilizer application monitoring device 4.

[0096] S3.2, Controller 6-2, combined with the set fertilizer application rate per mu, calculates the theoretical fertilizer application rate at the current machine forward speed according to Formula 4;

[0097] Formula 4

[0098] In formula 4, Q 理论 The theoretical fertilizer application rate at the current machine's forward speed is expressed in g / s; M is the set fertilizer application rate per acre, expressed in kg; v is the machine's forward speed, expressed in m / s; L is the machine's working width, L=2.7m; N is the number of counter-rotating double helix fertilizer applicators 2, N=6;

[0099] S3.3, Controller 6-2 compares the actual fertilizer application rate with the theoretical fertilizer application rate at the current machine forward speed. If the actual fertilizer application rate does not match the theoretical fertilizer application rate, then the speed of stepper motor 6-3 is controlled by PID according to formula 5.

[0100] Formula 5

[0101] In Formula 5, n is the stepper motor speed, in r / min; Qn This represents the fertilizer application rate when the stepper motor speed is n, expressed in g / s.

[0102] This invention example measures the amount of fertilizer applied at different stepper motor speeds using bench tests, establishing a mathematical model relationship between stepper motor speed and fertilizer application rate, i.e., Formula 5; the controller 6-2... Figure 9 The stepper motor control method in this paper uses PID control to enable the stepper motor to stably and quickly adjust the actual fertilizer application amount to the theoretical fertilizer application amount, thereby realizing closed-loop control of the fertilizer application amount; ultimately achieving uniform and precise fertilization operations.

[0103] The above description is merely a preferred embodiment of the present invention, but the scope of patent protection is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A wheat fertilizing device based on closed-loop control, characterized by, The wheat fertilization device includes a frame (3) and a fertilizer box (1), a counter-rotating double helix fertilizer dispenser (2), a fertilizer application monitoring device (4), a furrow opener (5), and a fertilizer application control system (6) installed on the frame (3). The fertilizer box (1) includes a front box panel (1-1), side panels (1-2), a rear box panel (1-5), a front inclined bottom panel (1-6), and a rear inclined bottom panel (1-7); the two side panels (1-2) are fixed to both sides of the front box panel (1-1) and the rear box panel (1-5); the front inclined bottom panel (1-6) and the rear inclined bottom panel (1-7) are fixed to the bottom of the front box panel (1-1), the rear box panel (1-5), and the two side panels (1-2), forming a funnel-shaped bottom; the bottom of the funnel-shaped box is provided with multiple pairs of fertilizer outlets (1-8) at equal intervals along the transverse direction of the machine. Below each pair of fertilizer outlets (1-8), there is a counter-rotating double helix fertilizer discharger (2) fixed to the bottom of the funnel-shaped box. The counter-rotating double helix fertilizer discharger (2) includes a left fertilizer discharger shell (2-1), a right fertilizer discharger shell (2-2), a counter-rotating fertilizer discharge spiral (2-3), and a fertilizer discharge tube (2-6); the left fertilizer discharger shell (2-1) and the right fertilizer discharger shell (2-2) are hollow cylindrical tubes; the right end of the left fertilizer discharger shell (2-1) and the left end of the right fertilizer discharger shell (2-2) are coaxially fixed to each other to form a fertilizer discharge chamber; the counter-rotating fertilizer discharge spiral (2-3) is arranged in the fertilizer discharge chamber; The counter-rotating fertilizer discharge spiral (2-3) is composed of two fertilizer discharge spirals with the same structural parameters but opposite rotation directions; the top of the left fertilizer discharger shell (2-1) and the top of the right fertilizer discharger shell (2-2) are both provided with fertilizer inlets (2-4) corresponding to the fertilizer outlet (1-8); the bottom of the left fertilizer discharger shell (2-1) is provided with a fertilizer discharge port (2-5), which is located below the center of the counter-rotating fertilizer discharge spiral (2-3) and is connected to the fertilizer discharge pipe (2-6); The frame (3) includes a crossbeam (3-1), a fertilizer tank mounting plate (3-2), a fertilizer tank connecting plate (3-3), a fertilizer tank support beam (3-4), a triangular fixing plate (3-5), a support beam support plate (3-6), and a crossbeam sealing plate (3-7); the crossbeam (3-1) is horizontally arranged below the fertilizer tank (1), with a crossbeam sealing plate (3-7) fixed to each end; a pair of fertilizer tank mounting plates (3-2) are fixed to the crossbeam (3-1); two triangular fixing plates (3-5) are fixed to the side plates (1-2) at the left and right ends of the fertilizer tank (1); the front A pair of support beam plates (3-6) are provided on both the inclined base plate (1-6) and the rear inclined base plate (1-7); two fertilizer box support beams (3-4) are arranged below the front inclined base plate (1-6) and the rear inclined base plate (1-7) and are fixedly connected to the triangular fixing plate (3-5) and the support beam plate (3-6); the fertilizer box mounting plate (3-2) is fixedly connected to the two fertilizer box support beams (3-4) through two fertilizer box connecting plates (3-3); multiple fertilizer applicators (5) corresponding one-to-one with the counter-rotating double helix fertilizer applicator (2) are fixedly connected to the crossbeam (3-1); The fertilizer applicator (5) includes an applicator body (5-1), a reflective fertilizer applicator tube (5-3), and an applicator plow (5-4); the applicator body (5-1) is fixed to a crossbeam (3-1); the applicator plow (5-4) is installed at the front of the bottom end of the applicator body (5-1); the reflective fertilizer applicator tube (5-3) is fixed to the rear end face of the applicator body (5-1), and the fertilizer inlet at the bottom end of the reflective fertilizer applicator tube (5-3) is located at the rear of the bottom end of the applicator body (5-1). A fertilizer application monitoring device (4) is installed between the reflective fertilizer application pipe (5-3) of each fertilizer ditch opener (5) and the fertilizer discharge pipe (2-6) of the corresponding counter-rotating double helix fertilizer discharger (2). The fertilizer application monitoring device (4) includes a housing (4-1), a monitoring circuit board (4-2), a monitoring electrode plate (4-3), a differential electrode plate (4-4), a mounting bracket (4-5), a fertilizer discharge connecting pipe (4-6), and a wiring pipe (4-7). The mounting bracket (4-5) is located inside the outer shell (4-1). The mounting bracket (4-5) consists of a rectangular connecting pipe bracket and a rectangular differential plate bracket fixed in parallel. The rectangular connecting pipe bracket and the rectangular differential plate bracket are composed of a top plate, a left side plate, a right side plate, and a bottom plate. The fertilizer discharge connecting pipe (4-6) passes vertically through the top and bottom plates of the rectangular connecting pipe bracket and the top and bottom plates of the outer shell (4-1). The top end of the fertilizer discharge connecting pipe (4-6) is connected to the fertilizer discharge pipe (2-6) of the counter-rotating double helix fertilizer discharger (2), and the bottom end is connected to the reflective fertilizer discharge pipe (5) of the fertilizer ditch opener (5). -3) Connection; The monitoring electrode (4-3) is fixed to the front and rear faces of the rectangular connecting pipe bracket; The differential electrode (4-4) is fixed to the inner walls of the left and right sides of the rectangular differential electrode bracket; The monitoring circuit board (4-2) is fixed to the outer surface of the side plate of the rectangular connecting pipe bracket and is electrically connected to the monitoring electrode (4-3) and the differential electrode (4-4) respectively; The line tube (4-7) is set on the bottom plate of the outer shell (4-1), located below the monitoring circuit board (4-2), and is used to lead the line of the monitoring circuit board (4-2) to the fertilizer application control system (6). The monitoring circuit board (4-2) includes an STM32F103C8T6 chip, an AD7745 chip, a TJA1050 chip, and an HT7833 chip. It provides stable power to the monitoring circuit board (4-2), collects and processes the capacitance values ​​measured by the monitoring plate (4-3) and the differential plate (4-4), and communicates with the fertilizer application control system (6). The monitoring circuit board (4-2) connects the capacitor plates of the monitoring plate (4-3) and the differential plate (4-4) in a differential mode. The first capacitor plate of the monitoring plate (4-3) and the first capacitor plate of the differential plate (4-4) are respectively connected to the EXCA of the AD7745 chip. The excitation pin is connected; the second capacitor plate of the monitoring plate (4-3) is connected to the CIN(+) pin of the AD7745 chip as a positive capacitor input; the second capacitor plate of the differential plate (4-4) is connected to the CIN(-) pin of the AD7745 chip as a negative capacitor input; the 5V power supply input by the fertilizer application control system (6) is filtered by capacitors and powered by the HT7833 chip to the monitoring circuit board (4-2); the STM32F103C8T6 chip reads the data value measured by the AD7745 chip and converts it into a capacitance value; the capacitance value is transmitted to the fertilizer application control system (6) via CAN communication through the TJA1050 chip. The fertilizer application control system (6) includes an electrical control box (6-1), a controller (6-2), a stepper motor (6-3), a stepper motor driver (6-4), a sprocket (6-5), a machine attitude sensor (6-6), a speed measuring radar (6-7), a radar mounting bracket (6-8), and a motor bracket (6-9). The electrical control box (6-1) is installed on the outer end face of the side plate (1-2) of the fat box (1). Inside it are a controller (6-2), an LCD screen, a stepper motor driver (6-4), a machine attitude sensor (6-6), and a PWM signal amplifier. The controller (6-2) is an STM32F407ZGT6 development board, which is connected to the LCD screen, the PWM signal amplifier, the stepper motor driver (6-4), the machine attitude sensor (6-6), and the speed measuring radar (6-7). The stepper motor (6-3) is fixed to the triangular fixing plate (3-5) via the motor bracket (6-9). The power output shaft of the stepper motor (6-3) is connected to the fertilizer discharge shaft fixed to the shaft end of the counter-rotating fertilizer discharge screw (2-3) via the sprocket (6-5) and chain. The stepper motor (6-3) is connected to the stepper motor driver (6-4), and the stepper motor driver (6-4) is connected to the controller (6-2) via the PWM signal amplifier. The PWM signal amplifier can convert the I / O of the controller (6-2) into the I / O signal of the controller (6-2). The 3.3V PWM pulse signal output is boosted to 5V to reach the drive signal voltage range of the stepper motor driver (6-4); the machine posture sensor (6-6) is connected to the controller (6-2) to monitor the posture of the wheat fertilization device based on closed-loop control. The posture of the wheat fertilization device based on closed-loop control includes the raised idle state and the lowered working state; the speed measuring radar (6-7) is installed on the outside of the crossbeam sealing plate (3-7) through the radar mounting bracket (6-8); the controller (6-2) communicates with the monitoring circuit board (4-2) in the fertilizer amount monitoring device (4) through the CAN communication protocol to obtain the current actual fertilizer amount, and communicates with the machine posture sensor (6-6) through the IIC communication protocol to obtain the current working status of the machine, and obtains the current forward speed of the machine by reading the square wave signal frequency fed back by the speed measuring radar (6-7); and adjusts the stepper motor speed by outputting PWM signals of different frequencies; and displays the human-machine interface through the LCD screen.

2. The closed loop regulation based wheat fertilizing device according to claim 1, characterized in that, Two box support plates (1-3) are provided between the front box plate (1-1) and the rear box plate (1-5) to stabilize the fertilizer box structure; at least two fertilizer outlets (1-4) are provided on the rear inclined bottom plate (1-7) for discharging the remaining fertilizer after the fertilization operation is completed.

3. The wheat fertilization device based on closed-loop control according to claim 1, characterized in that, The total length L of the counter-rotating fertilizer discharge spiral (2-3) is 300mm, the outer diameter D of the spiral blade is 55mm, the outer diameter d of the spiral shaft is 25mm, the spiral blade pitch S is 30mm, the tooth root radius r is 2mm, and the combined angle α of the two fertilizer discharge spirals is -148°; the length l of the fertilizer discharge port (2-5) at the bottom of the left fertilizer discharger shell (2-1) is 70mm.

4. The wheat fertilization device based on closed-loop control according to claim 1, characterized in that, The shaft end of the counter-rotating fertilizer discharge spiral (2-3) has a square cross-section and is connected to the square fertilizer discharge shaft as a power input.

5. The wheat fertilization device based on closed-loop control according to claim 1, characterized in that, The front end face of the furrow opener body (5-1) is provided with a guard plate (5-2), which is located above the furrow opener plow head (5-4).

6. The wheat fertilization device based on closed-loop control according to claim 1, characterized in that, The fertilizer box (1) is provided with six pairs of fertilizer outlets (1-8), and six counter-rotating double helix fertilizer dispensers (2) and six fertilizer ditch openers (5) are set accordingly; among them, the six counter-rotating double helix fertilizer dispensers (2) are arranged at equal intervals along the transverse direction of the machine at the bottom of the fertilizer box (1); the interval between two adjacent fertilizer ditch openers (5) is 440mm.

7. The wheat fertilization device based on closed-loop control according to claim 1, characterized in that, The outer casing (4-1) is fixedly mounted on the upper end face of the crossbeam (3-1) by bolts. The outer casing (4-1) is made of metal. The monitoring electrode (4-3) and the differential electrode (4-4) are fixed to the mounting bracket (4-5) by glue. The mounting bracket (4-5) is made of steel plate. The bottom of the monitoring circuit board (4-2) is provided with an insulating layer and is fixed to the mounting bracket (4-5) by screws. The mounting bracket (4-5) is fixed to the outer casing (4-1) by bolts. The GND through hole on the monitoring circuit board (4-2) is grounded to the entire fertilizer application monitoring device (4) by screws.

8. The wheat fertilization device based on closed-loop control according to claim 1, characterized in that, The outer diameter of the fertilizer discharge connecting pipe (4-6) is 35mm; the monitoring electrode (4-3) is composed of a pair of 50×100mm PCBs, with a copper-clad area of ​​40×90mm and a spacing of 40mm; the differential electrode (4-4) is composed of a pair of 40×50mm PCBs, with a copper-clad area of ​​40×45mm and a spacing of 20mm; both the monitoring electrode (4-3) and the differential electrode (4-4) have a solder resist layer on the copper-clad side of their PCBs.

9. The wheat fertilization device based on closed-loop control according to claim 1, characterized in that, The speed measuring radar (6-7) is installed at a height of 40cm and at an angle of 35° to the ground.

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