Wheat fertilizing device and method based on closed-loop regulation and control

Abstract

The invention relates to a wheat fertilizing device and method based on closed-loop regulation and control. The wheat fertilizing device comprises a rack, and a fertilizer box, a counter-rotating type double-helix fertilizer apparatus, a fertilizing amount monitoring device, a furrow opener and a fertilizing amount control system which are mounted on the rack, the counter-rotating type double-helix fertilizer apparatus comprises a left fertilizer apparatus shell, a right fertilizer apparatus shell, a counter-rotating type fertilizer apparatus helix and a fertilizer apparatus pipe; the rack comprises a cross beam, a fertilizer box mounting plate, a fertilizer box connecting plate, a fertilizer box supporting beam, a triangular fixing plate, a supporting beam supporting plate and a cross beam sealing plate; the fertilization furrow opener comprises a furrow opener main body, a reflection type fertilization pipe and a furrow opener plowshare; the fertilization amount monitoring device comprises a shell, a monitoring circuit board, a monitoring polar plate, a differential polar plate, a mounting bracket, a fertilizer discharge connecting pipe and a line pipe; the fertilizing amount control system comprises an electric cabinet, a controller, a stepping motor, a stepping motor driver, a chain wheel, a machine attitude sensor, a speed measuring radar, a radar mounting bracket and a motor bracket.

Description

Technical Field

[0001] The present invention belongs to the technical field of agricultural machinery, and particularly relates to a wheat fertilizing device and method based on closed-loop regulation. Background Art

[0002] Fertilization operation, as an important part of wheat planting, can provide necessary nutrients for wheat and has a direct impact on the yield and quality of wheat. Due to the heavy dependence on the input of agricultural production factors, there are still problems such as excessive application of chemical fertilizers and low utilization efficiency of fertilization in China. Therefore, it is of great significance to use chemical fertilizers reasonably, reduce the application amount of chemical fertilizers, and improve the fertilization utilization rate. Most of the current wheat fertilizing devices use open-loop control to control the fertilization amount. For example, in the "Wheat drill control device and control method" disclosed in the Chinese invention patent application "CN116649050A", the traditional ground wheel drive is changed to electric drive to control the fertilization amount. The rotation speed of the motor is obtained through a rotary encoder installed on the fertilizer discharge shaft. According to the constructed collaborative algorithm of the machine travel speed and the motor speed, the fertilization amount is changed by adjusting the motor speed, realizing the indirect adjustment of the fertilization amount. However, this method takes the motor speed as the main control object, and the fertilization amount is the result of the change in the motor speed, which will cause a certain error in the accuracy of the fertilization operation. Therefore, a method for directly regulating the fertilization amount is needed to achieve precise control of the fertilization amount. Summary of the Invention

[0003] To overcome the deficiencies of the existing electronically controlled fertilization technology and the problem of uneven fertilizer discharge of the fertilizer distributor, the purpose of the present invention is to provide a wheat fertilizing device and method based on closed-loop regulation, which can use the fertilization amount as a feedback input to control the discharged fertilizer amount, adjust the fertilization amount according to the operating speed of the machine, and achieve uniform and precise fertilization operation.

[0004] To achieve the above purpose, the present invention provides the following technical solutions:

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

[0006] The fertilizer box 1 includes a front box body plate 1-1, side plates 1-2, a rear box body plate 1-5, a front inclined bottom plate 1-6, and a rear inclined bottom plate 1-7; the two side plates 1-2 are fixedly connected to both sides of the front box body plate 1-1 and the rear box body plate 1-5; the front inclined bottom plate 1-6 and the rear inclined bottom plate 1-7 are fixedly connected to the bottom ends of the front box body plate 1-1, the rear box body plate 1-5, and the two side plates 1-2 to form a funnel-shaped box bottom; a plurality of pairs of fertilizer outlets 1-8 are arranged at equal intervals along the transverse direction of the machine on the funnel-shaped box bottom.

[0007] A pair of counter-rotating double-helix fertilizer distributors 2 fixedly connected to the bottom of the funnel-shaped box body are correspondingly arranged below each fertilizer outlet 1-8.

[0008] The counter-rotating double-helix fertilizer distributor 2 includes a left fertilizer distributor housing 2-1, a right fertilizer distributor housing 2-2, a counter-rotating fertilizer-distributing helix 2-3, and a fertilizer discharge pipe 2-6; the left fertilizer distributor housing 2-1 and the right fertilizer distributor housing 2-2 are hollow cylindrical pipe bodies; the right end of the left fertilizer distributor housing 2-1 and the left end of the right fertilizer distributor housing 2-2 are coaxially and fixedly connected to form a fertilizer discharge chamber; the counter-rotating fertilizer-distributing helix 2-3 is arranged in the fertilizer discharge chamber; the counter-rotating fertilizer-distributing helix 2-3 is composed of two fertilizer-distributing helices with the same structural parameters and opposite helix directions; fertilizer inlets 2-4 corresponding to the fertilizer outlets 1-8 are provided at the tops of both the left fertilizer distributor housing 2-1 and the right fertilizer distributor housing 2-2; a fertilizer discharge port 2-5 is provided at the bottom of the left fertilizer distributor housing 2-1, and the fertilizer discharge port 2-5 is located below the center position of the counter-rotating fertilizer-distributing helix 2-3 and is connected to the fertilizer discharge pipe 2-6.

[0009] The frame 3 includes a cross beam 3-1, a fertilizer tank mounting plate 3-2, a fertilizer tank connecting plate 3-3, a fertilizer tank supporting beam 3-4, a triangular fixing plate 3-5, a supporting beam supporting plate 3-6, and a cross beam sealing plate 3-7; the cross beam 3-1 is horizontally arranged below the fertilizer tank 1, and a cross beam sealing plate 3-7 is fixedly connected to each end; a pair of fertilizer tank mounting plates 3-2 are fixedly connected to the cross beam 3-1; two triangular fixing plates 3-5 are fixedly connected to the side plates 1-2 at the left and right ends of the fertilizer tank 1; a pair of supporting beam supporting plates 3-6 are provided on both the front inclined bottom plate 1-6 and the rear inclined bottom plate 1-7; two fertilizer tank supporting beams 3-4 are arranged below the front inclined bottom plate 1-6 and the rear inclined bottom plate 1-7 and are fixedly connected to the triangular fixing plates 3-5 and the supporting beam supporting plates 3-6; the fertilizer tank mounting plates 3-2 are fixedly connected to the two fertilizer tank supporting beams 3-4 through two fertilizer tank connecting plates 3-3; a plurality of fertilizer application furrowing devices 5 corresponding one-to-one to the counter-rotating double-helix fertilizer distributors 2 are fixedly connected to the cross beam 3-1 for opening fertilizer furrows.

[0010] The fertilizer application furrowing device 5 includes a furrowing device main body 5-1, a reflective fertilizer pipe 5-3, and a furrowing device plowshare 5-4; the furrowing device main body 5-1 is fixedly connected to the cross beam 3-1; the furrowing device plowshare 5-4 is installed at the front part of the bottom end of the furrowing device main body 5-1; the reflective fertilizer pipe 5-3 is fixedly connected to the rear end face of the furrowing device main body 5-1, and the fertilizer outlet at the bottom end of the reflective fertilizer pipe 5-3 is located at the rear part of the bottom end of the furrowing device main body 5-1.

[0011] A fertilizer application rate monitoring device 4 is arranged between the reflective fertilizer pipe 5-3 of each fertilizer application furrowing device 5 and the fertilizer discharge pipe 2-6 of the corresponding counter-rotating double-helix fertilizer distributor 2.

[0012] The fertilization amount monitoring device 4 includes a housing 4-1, a monitoring circuit board 4-2, monitoring electrodes 4-3, differential electrodes 4-4, a mounting bracket 4-5, a fertilizer discharging connecting pipe 4-6, and a wiring pipe 4-7.

[0013] The mounting bracket 4-5 is located inside the housing 4-1. The mounting bracket 4-5 is composed of a rectangular connecting pipe bracket and a rectangular differential electrode bracket that are fixedly connected in parallel. The rectangular connecting pipe bracket and the rectangular differential electrode bracket are composed of a top plate, a left side plate, a right side plate, and a bottom plate. The fertilizer discharging connecting pipe 4-6 vertically passes through the top plate and the bottom plate of the rectangular connecting pipe bracket and the top plate and the bottom plate of the housing 4-1. The top end of the fertilizer discharging connecting pipe 4-6 is connected to the fertilizer discharging pipe 2-6 of the counter-rotating double-screw fertilizer discharger 2, and the bottom end is connected to the reflective fertilizer application pipe 5-3 of the fertilizer application opener 5. The monitoring electrodes 4-3 are fixedly connected to the front end face and the rear end face of the rectangular connecting pipe bracket. The differential electrodes 4-4 are fixedly connected to the inner walls of the left side plate and the right side plate 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 electrodes 4-3 and the differential electrodes 4-4 respectively. The wiring pipe 4-7 is arranged on the bottom plate of the housing 4-1 and is located below the monitoring circuit board 4-2 for leading out the circuit of the monitoring circuit board 4-2 to the fertilization amount control system 6.

[0014] The monitoring circuit board 4-2 includes an STM32F103C8T6 chip, an AD7745 chip, a TJA1050 chip, and an HT7833 chip, and realizes the functions of stably powering the monitoring circuit board 4-2, collecting and processing the capacitance values measured by the monitoring electrodes 4-3 and the differential electrodes 4-4, and communicating with the fertilization amount control system 6. The monitoring circuit board 4-2 is connected to the capacitance plates of the monitoring electrodes 4-3 and the differential electrodes 4-4 in a differential mode. The first capacitance plates of the monitoring electrodes 4-3 and the differential electrodes 4-4 are respectively connected to the EXCA excitation pins of the AD7745 chip. The second capacitance plate of the monitoring electrodes 4-3 is connected to the CIN(+) pin of the AD7745 chip as the positive capacitance input. The second capacitance plate of the differential electrodes 4-4 is connected to the CIN(-) pin of the AD7745 chip as the negative capacitance input. The 5V power supply input by the fertilization amount control system 6 powers the monitoring circuit board 4-2 through capacitor filtering and the HT7833 chip. The STM32F103C8T6 chip reads the data values measured by the AD7745 chip, converts them into capacitance values, and transmits the capacitance values to the fertilization amount control system 6 through the TJA1050 chip using the CAN communication method.

[0015] The fertilization rate control system 6 includes an electric 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 measurement radar 6-7, a radar mounting bracket 6-8, and a motor bracket 6-9.

[0016] The electric control box 6-1 is installed on the outer end face of the side plate 1-2 of the fertilizer tank 1, and inside it are installed a controller 6-2, a liquid crystal display 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 liquid crystal display screen, the PWM signal amplifier, the stepper motor driver 6-4, the machine attitude sensor 6-6, and the speed measurement radar 6-7; the stepper motor 6-3 is fixedly connected to the triangular fixing plate 3-5 through the motor bracket 6-9, and the power output shaft of the stepper motor 6-3 is fixedly connected to the fertilizer discharge shaft at the end of the shaft of the counter-rotating fertilizer discharge spiral 2-3 through a sprocket 6-5 and a 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 through the PWM signal amplifier. The PWM signal amplifier can boost the 3.3V PWM pulse signal output from the IO port of the controller 6-2 to 5V to reach the drive signal voltage range of the stepper motor driver 6-4; the machine attitude sensor 6-6 is connected to the controller 6-2 and is used to monitor the attitude of the wheat fertilization device based on closed-loop regulation. The attitude of the wheat fertilization device based on closed-loop regulation includes the lifted idle state and the lowered working state; the speed measurement radar 6-7 is installed outside 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 fertilization rate monitoring device 4 through the CAN communication protocol to obtain the current actual fertilization rate, and communicates with the machine attitude sensor 6-6 through the IIC communication protocol to obtain the current working state of the machine, and obtains the current forward speed of the machine by reading the frequency of the square wave signal fed back by the speed measurement radar 6-7; and adjusts the speed of the stepper motor by outputting PWM signals of different frequencies; and displays the human-machine interaction interface through the liquid crystal display screen.

[0017] There are two box body support plates 1-3 between the front box body plate 1-1 and the rear box body plate 1-5 to make the structure of the fertilizer tank box body stable; there are at least two surplus fertilizer outlets 1-4 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 pitch S of the spiral blade is 30mm, the root fillet radius r of the tooth is 2mm, and the combined angle ɑ of the two sections of the fertilizer discharge spiral is -148°; the length l of the fertilizer discharge port 2-5 at the bottom of the left fertilizer discharge housing 2-1 is 70mm.

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

[0020] A guard plate 5-2 is provided on the front end face of the opener body 5-1, and the guard plate 5-2 is located above the opener plowshare 5-4.

[0021] The fertilizer box 1 is provided with six pairs of fertilizer discharging ports 1-8, and six counter-rotating double spiral fertilizer discharging devices 2 and six fertilizer applying openers 5 are correspondingly arranged; among them, the six counter-rotating double spiral fertilizer discharging devices 2 are arranged at equal intervals along the transverse direction of the machine at the bottom of the fertilizer box 1; the interval distance between two adjacent fertilizer applying openers 5 is 440 mm.

[0022] The outer shell 4-1 is fixedly installed on the upper end face of the cross beam 3-1 through bolts, and the material of the outer shell 4-1 is metal; the monitoring electrode plate 4-3 and the differential electrode plate 4-4 are fixedly glued on the mounting bracket 4-5; the mounting bracket 4-5 is made of steel plate; an insulating layer is provided at the bottom of the monitoring circuit board 4-2 and is fixedly installed on the mounting bracket 4-5 through screws, the mounting bracket 4-5 is fixedly connected to the outer shell 4-1 through bolts, and the GND through hole on the monitoring circuit board 4-2 is grounded together with the entire fertilizer application amount monitoring device 4 through screws.

[0023] The outer diameter of the fertilizer discharging connecting pipe 4-6 is 35 mm; the monitoring electrode plate 4-3 is composed of a pair of circuit boards PCB of 50×100 mm, the copper-clad area on it is 40×90 mm, and the interval distance is 40 mm; the differential electrode plate 4-4 is composed of a pair of circuit boards PCB of 40×50 mm, the copper-clad area on it is 40×45 mm, and the interval distance is 20 mm; a solder mask layer is provided on the copper-clad side of the circuit boards PCB of the monitoring electrode plate 4-3 and the differential electrode plate 4-4.

[0024] The installation height of the speed measurement radar 6-7 is 40 cm, and the included angle with the ground is 35°.

[0025] A wheat fertilization adjustment method using the wheat fertilization device based on closed-loop regulation described above includes the following steps:

[0026] S1. System initialization and setting of the fertilization amount per mu;

[0027] The controller 6-2 is initialized, the fertilizer application amount monitoring device 4, the machine attitude sensor 6-6, the speed measurement radar 6-7 and the stepping motor 6-3 are started, and the fertilization amount per mu is set through the human-computer interaction interface.

[0028] S2. Judging the operation state of the wheat fertilization device;

[0029] When the implement attitude sensor 6-6 detects that the wheat fertilizing device is in the raised idle state, the stepping motor 6-3 is turned off and the fertilizing operation is paused; when the implement attitude sensor 6-6 detects that the wheat fertilizing device is in the lowered working state, the stepping motor 6-3 is started and the fertilizing operation begins.

[0030] S3. Closed-loop regulation of fertilization amount;

[0031] The controller 6-2 closes the loop to adjust the rotation speed of the stepping motor 6-3 according to the forward speed of the implement measured by the speed radar 6-7, the set fertilization amount per mu, and the actual fertilization amount measured by the fertilization amount monitoring device.

[0032] S3.1. The fertilization amount monitoring device measures the actual fertilization amount at the current forward speed of the implement and transmits it to the controller 6-2;

[0033]

[0034]

[0035]

[0036] In Formulas 1 to 3, DATA is the actual measured value of the AD7745 chip during the fertilization amount monitoring process; ε0 is the permittivity of vacuum medium, with the unit of pF / mm; V 肥料 is the volume occupied by the fertilizer in the space directly opposite to the monitoring electrode plate 4-3, in unit of mm 3 ; d 监测 is the distance between the first capacitor electrode plate and the second capacitor electrode plate of the monitoring electrode plate 4-3, with the unit of mm; ε 肥料 is the relative permittivity of the fertilizer; ε 空气 is the relative permittivity of air; C is the capacitance value measured by the fertilization amount monitoring device, with the unit of pF; 0x800000 is a hexadecimal number, which is the intermediate value of the chip's capacitance measurement range of -4 pF to 4 pF and the measurement value of 0x000000 to 0xFFFFFF, equivalent to the decimal number 0; Q 实际 is the actual fertilization amount, with the unit of g / s;

[0037] S3.2. The controller 6-2 combines the set fertilization amount per mu and calculates the theoretical fertilization amount at the current forward speed of the implement according to Formula 4;

[0038]

[0039] In Formula 4, Q 理论$Q_0$ is the theoretical fertilization amount at the current forward speed of the implement, with the unit of g / s; M is the set fertilization amount per mu, with the unit of kg; v is the forward speed of the implement, with the unit of m / s; L is the working width of the implement, with the unit of m; N is the number of the counter-rotating double-helix fertilizer distributors 2.

[0040] S3.3. The controller 6-2 compares the actual fertilization amount and the theoretical fertilization amount at the current forward speed of the implement. If the actual fertilization amount does not match the theoretical fertilization amount, the rotation speed of the stepper motor 6-3 is PID-controlled according to Formula 5.

[0041]

[0042] In Formula 5, n is the rotation speed of the stepper motor, with the unit of r / min; $Q$ n is the fertilization amount at the rotation speed n of the stepper motor, with the unit of g / s.

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

[0044] 1. A wheat fertilization device based on closed-loop regulation of the present invention realizes real-time adjustment of the fertilization amount through a counter-rotating double-helix fertilizer distributor, a fertilization amount monitoring device based on a capacitance sensor, and a fertilization amount control system based on closed-loop control. It realizes taking the measured actual fertilization amount as feedback and inputting it into the control system to adjust the fertilization amount, avoiding the reduction of fertilization accuracy by the fertilization amount control system composed of closed-loop control of the motor rotation speed, reducing labor intensity, and improving operation efficiency.

[0045] 2. The counter-rotating double-helix fertilizer distributor of the present invention is provided with a counter-rotating fertilizer discharge helix composed of two sections of fertilizer discharge spiral blades with the same structural parameters and opposite rotation directions, which can compensate for the fertilization amount fluctuation effect caused by a single fertilizer discharge spiral, enabling fertilizer particles to be evenly discharged from the fertilizer distributor and improving the utilization rate of chemical fertilizer resources.

[0046] 3. The fertilization amount monitoring device based on a capacitance sensor of the present invention measures the fertilization amount in a differential mode, which can resist the influence of external environments such as temperature changes, operation vibrations, and electromagnetic interference, improving the measurement accuracy of the fertilization amount; and this device has high measurement accuracy and sensitive response to the fertilization amount, and is applicable to monitoring different types of fertilizers.

[0047] 4. The fertilizer application rate control system based on closed-loop control of the present invention realizes intelligence and automation through electronic control technology. By collecting information such as the speed and attitude of the implement measured by sensors, the actual fertilizer application rate data measured by the fertilizer application rate monitoring device is transmitted as feedback data to the controller. The controller combines the sensor measurement data and the actual fertilizer application rate data, and uses PID to adjust the rotational speed of the stepping motor in real time to achieve uniform and precise fertilizer application operations. This fertilizer application rate control system measures the falling fertilizer application rate and adjusts the fertilizer application rate in real time, realizing closed-loop control of the fertilizer application rate adjustment. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 is the overall structural schematic diagram of the wheat fertilizer application device based on closed-loop regulation of the present invention;

[0049] Figure 2 is the top view structural schematic diagram of the wheat fertilizer application device based on closed-loop regulation of the present invention;

[0050] Figure 3 is the front view structural schematic diagram of the wheat fertilizer application device based on closed-loop regulation of the present invention;

[0051] Figure 4a is the left view structural schematic diagram of the wheat fertilizer application device based on closed-loop regulation of the present invention;

[0052] Figure 4b is the left view structural schematic diagram of the wheat fertilizer application device based on closed-loop regulation of the present invention;

[0053] Figure 5 is the overall structural schematic diagram of the counter-rotating double-helix fertilizer distributor 4;

[0054] Figure 6a is the structural schematic diagram of the counter-rotating fertilizer distribution screw;

[0055] Figure 6b is the structural schematic diagram of the counter-rotating fertilizer distribution screw;

[0056] Figure 7 is the overall structural schematic diagram and internal structural schematic diagram of the fertilizer application rate monitoring device;

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

[0058] Figure 9 is the PID control scheme diagram of the stepping motor of the wheat fertilizer application device based on closed-loop regulation of the present invention;

[0059] Figure 10 is the system flow chart of the wheat fertilizer application device based on closed-loop regulation of the present invention.

[0060] The reference numerals therein are:

[0061] 1. Fertilizer box

[0062] 1-1. Front box plate 1-2. Side plate

[0063] 1-3. Box support plate 1-4. Leftover fertilizer opening

[0064] 1-5. Rear box plate 1-6. Front inclined bottom plate

[0065] 1-7. Rear inclined bottom plate 1-8. Fertilizer outlet

[0066] 2. Counter-rotating double-screw fertilizer distributor

[0067] 2-1. Left fertilizer distributor housing 2-2. Right fertilizer distributor housing

[0068] 2-3. Counter-rotating fertilizer-distributing screw 2-4. Fertilizer inlet

[0069] 2-5. Fertilizer outlet 2-6. Fertilizer discharge pipe

[0070] 3. Frame

[0071] 3-1. Cross beam 3-2. Fertilizer box mounting plate

[0072] 3-3. Fertilizer box connecting plate 3-4. Fertilizer box supporting beam

[0073] 3-5. Triangular fixing plate 3-6. Supporting beam support plate

[0074] 3-7. Cross beam cover plate

[0075] 4. Fertilizer application monitoring device

[0076] 4-1. Outer shell 4-2. Monitoring circuit board

[0077] 4-3. Monitoring electrode plate 4-4. Differential electrode plate

[0078] 4-5. Mounting bracket 4-6. Fertilizer discharge connecting pipe

[0079] 4-7. Wiring pipe

[0080] 5. Fertilizer application furrow opener

[0081] 5-1. Furrow opener body 5-2. Guard plate

[0082] 5-3. Reflective fertilizer application pipe 5-4. Furrow opener plowshare

[0083] 6. Fertilizer application rate control system

[0084] 6-1. Electric control box 6-2. Controller

[0085] 6-3, Stepper motor 6-4, Stepper motor driver

[0086] 6-5, Sprocket 6-6, Implement attitude sensor

[0087] 6-7, Speed measurement radar 6-8, Radar mounting bracket

[0088] 6-9, Motor bracket Detailed implementation manner

[0089] The present invention will be further described below in conjunction with the accompanying drawings and examples.

[0090] As Figure 1 shown, a wheat fertilizing device based on closed-loop regulation of the present invention includes a frame 3 and a fertilizer tank 1, a counter-rotating double-helix fertilizer distributor 2, a fertilizing amount monitoring device 4, a furrow opener 5, and a fertilizing amount control system 6 based on closed-loop control, which are installed on the frame 3.

[0091] As Figure 2 shown, the fertilizer tank 1 includes a front box body plate 1-1, side plates 1-2, box body support plates 1-3, surplus fertilizer ports 1-4, a rear box body 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 fixedly connected to both sides of the front box body plate 1-1 and the rear box body plate 1-5; the front inclined bottom plate 1-6 and the rear inclined bottom plate 1-7 are fixedly connected to the bottom ends of the front box body plate 1-1, the rear box body plate 1-5, and the two side plates 1-2 to form a funnel-shaped box body bottom; the two box body support plates 1-3 are fixedly connected between the front box body plate 1-1 and the rear box body plate 1-5 by bolts to make the structure of the fertilizer tank box body stable; a plurality of pairs of fertilizer outlets 1-8 are arranged at equal intervals along the transverse direction of the implement on the funnel-shaped box body bottom; at least two surplus fertilizer ports 1-4 are provided on the rear inclined bottom plate 1-7 for discharging the remaining fertilizer after the fertilizing operation is completed.

[0092] As Figure 1 and Figure 3 shown, a counter-rotating double-helix fertilizer distributor 2 fixedly connected to the funnel-shaped box body bottom is correspondingly arranged below each pair of fertilizer outlets 1-8.

[0093] As Figure 5As shown in the figure, the counter-rotating double-helix fertilizer distributor 2 includes a left fertilizer distributor housing 2-1, a right fertilizer distributor housing 2-2, a counter-rotating fertilizer-distributing helix 2-3, a fertilizer inlet 2-4, a fertilizer outlet 2-5, and a fertilizer discharge pipe 2-6; the left fertilizer distributor housing 2-1 and the right fertilizer distributor housing 2-2 are hollow cylindrical tubes; the right end of the left fertilizer distributor housing 2-1 and the left end of the right fertilizer distributor housing 2-2 are coaxially connected to each other by bolts to form a fertilizer discharge chamber; the counter-rotating fertilizer-distributing helix 2-3 is arranged in the fertilizer discharge chamber; the counter-rotating fertilizer-distributing helix 2-3 is composed of two fertilizer-distributing helices with the same structural parameters and opposite helix directions; fertilizer inlets 2-4 corresponding to the fertilizer outlet 1-8 are provided at the tops of both the left fertilizer distributor housing 2-1 and the right fertilizer distributor housing 2-2; a fertilizer outlet 2-5 is provided at the bottom of the left fertilizer distributor housing 2-1, and the fertilizer outlet 2-5 is located below the center position of the counter-rotating fertilizer-distributing helix 2-3 and is connected to the fertilizer discharge pipe 2-6.

[0094] Restricted by the unique structural type, the traditional single-helix fertilizer distributor will inevitably produce a flow fluctuation effect, resulting in poor fertilizer discharge uniformity of the fertilizer distributor. Therefore, in the present invention, a fertilizer-distributing helix with the same structural parameters and opposite helix directions is added to form a counter-rotating fertilizer-distributing helix, which is used to mutually compensate for the fertilizer application amount fluctuation effect caused by the single helix and improve the fertilizer discharge uniformity of the fertilizer distributor.

[0095] The fertilizer discharge performance of the helix fertilizer distributor is analyzed through discrete element simulation, and the structural parameters of the counter-rotating double-helix fertilizer distributor are optimized. As Figure 6a and Figure 6b shown, the total length L of the counter-rotating fertilizer-distributing helix 2-3 is 300 mm, the outer diameter D of the helical blade is 55 mm, the outer diameter d of the helical shaft is 25 mm, the pitch S of the helical blade is 30 mm, the fillet radius r at the tooth root is 2 mm, and the combined angle ɑ of the two fertilizer-distributing helices is -148°. As Figure 5 shown, the length l of the fertilizer outlet 2-5 at the bottom of the left fertilizer distributor housing 2-1 is 70 mm.

[0096] Preferably, the axial end cross-section of the counter-rotating fertilizer-distributing helix 2-3 is square and is connected to a square fertilizer-distributing shaft as power input.

[0097] As Figure 3 and Figure 4bAs shown in the figure, the frame 3 includes a cross beam 3-1, a fertilizer tank mounting plate 3-2, a fertilizer tank connecting plate 3-3, a fertilizer tank supporting beam 3-4, a triangular fixing plate 3-5, a supporting beam support plate 3-6, and a cross beam sealing plate 3-7; the cross beam 3-1 is horizontally arranged below the fertilizer tank 1, and a cross beam sealing plate 3-7 is fixedly connected to each of the two ends; a pair of fertilizer tank mounting plates 3-2 are fixedly connected to the cross beam 3-1; two triangular fixing plates 3-5 are fixedly connected to the side plates 1-2 at the left and right ends of the fertilizer tank 1; a pair of supporting beam support plates 3-6 are provided on both the front inclined bottom plate 1-6 and the rear inclined bottom plate 1-7; two fertilizer tank supporting beams 3-4 are arranged below the front inclined bottom plate 1-6 and the rear inclined bottom plate 1-7, and are fixedly connected to the triangular fixing plates 3-5 and the supporting beam support plates 3-6; the fertilizer tank mounting plate 3-2 is fixedly connected to the two fertilizer tank supporting beams 3-4 through two fertilizer tank connecting plates 3-3. A plurality of fertilizing furrow openers 5 corresponding to the counter-rotating double spiral fertilizer distributors 2 one by one are fixedly connected to the cross beam 3-1 for opening fertilizer furrows.

[0098] As Figure 4a and Figure 4b shown in the figure, the fertilizing furrow opener 5 includes a furrow opener body 5-1, a reflective fertilizer application pipe 5-3, and a furrow opener plowshare 5-4; the furrow opener body 5-1 is fixedly connected to the cross beam 3-1; the furrow opener plowshare 5-4 is installed at the front part of the bottom end of the furrow opener body 5-1 through bolts; the reflective fertilizer application pipe 5-3 is fixedly connected to the rear end face of the furrow opener body 5-1, and the fertilizer application port at the bottom end of the reflective fertilizer application pipe 5-3 is located at the rear part of the bottom end of the furrow opener body 5-1.

[0099] 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 plowshare 5-4.

[0100] In the embodiment of the present invention, the fertilizer tank 1 is provided with six pairs of fertilizer outlet openings 1-8, corresponding to six counter-rotating double spiral fertilizer distributors 2 and six fertilizing furrow openers 5; among them, the six counter-rotating double spiral fertilizer distributors 2 are arranged at equal intervals along the transverse direction of the machine at the bottom of the fertilizer tank 1. The interval distance between two adjacent fertilizing furrow openers 5 is 440 mm.

[0101] A fertilizer application rate monitoring device 4 is provided between the reflective fertilizer application pipe 5-3 of each fertilizing furrow opener 5 and the fertilizer discharge pipe 2-6 of the corresponding counter-rotating double spiral fertilizer distributor 2.

[0102] As Figure 7 shown in the figure, the fertilizer application rate 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 line pipe 4-7;

[0103] The mounting bracket 4-5 is located inside the housing 4-1. The mounting bracket 4-5 is composed of a rectangular connecting pipe bracket and a rectangular differential electrode bracket that are fixedly connected in parallel. The rectangular connecting pipe bracket and the rectangular differential electrode bracket are composed of a top plate, a left side plate, a right side plate, and a bottom plate. The fertilizer discharging connecting pipe 4-6 vertically passes through the top plate and the bottom plate of the rectangular connecting pipe bracket and the top plate and the bottom plate of the housing 4-1. The top end of the fertilizer discharging connecting pipe 4-6 is connected to the fertilizer discharging pipe 2-6 of the counter-rotating double spiral fertilizer discharger 2, and the bottom end is connected to the reflective fertilizer applying pipe 5-3 of the fertilizer applying opener 5. The monitoring electrode plate 4-3 is fixedly connected to the front end face and the rear end face of the rectangular connecting pipe bracket. The differential electrode plate 4-4 is fixedly connected to the inner walls of the left side plate and the right side plate 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 plate 4-3 and the differential electrode plate 4-4 respectively. The wiring pipe 4-7 is arranged on the bottom plate of the housing 4-1 and is located below the monitoring circuit board 4-2 for leading out the circuit of the monitoring circuit board 4-2 to the fertilizer application rate control system 6.

[0104] The housing 4-1 is fixedly installed on the upper end face of the cross beam 3-1 by bolts. The fertilizer discharging connecting pipe 4-6 is vertically installed to reduce the monitoring error caused by fertilizer collision. The housing 4-1 is made of metal, which can shield external signals and reduce the influence of electromagnetic interference on the measurement of fertilizer application rate. The monitoring electrode plate 4-3 and the differential electrode plate 4-4 are fixed on the mounting bracket 4-5 by glue. To reduce the mutual influence between the monitoring electrode plate 4-3 and the differential electrode plate 4-4 when monitoring the fertilizer application rate, the mounting bracket 4-5 is made of steel plate.

[0105] An insulating layer is provided at the bottom of the monitoring circuit board 4-2, and it is fixed on the mounting bracket 4-5 by screws. The mounting bracket 4-5 is fixedly connected to the housing 4-1 by bolts. The GND through hole on the monitoring circuit board 4-2 is grounded with the entire fertilizer application rate monitoring device 4 by screws to enhance the anti-interference ability and avoid vibration inside the fertilizer application rate monitoring device 4 during the fertilizer application operation.

[0106] As Figure 8As shown, the monitoring circuit board 4-2 includes an STM32F103C8T6 chip, an AD7745 chip, a TJA1050 chip, and an HT7833 chip, which realize the functions of stably powering the monitoring circuit board 4-2, collecting and processing the capacitance values measured by the monitoring electrode plate 4-3 and the differential electrode plate 4-4, and communicating with the fertilization amount control system 6; the monitoring circuit board 4-2 is connected to the capacitance plates of the monitoring electrode plate 4-3 and the differential electrode plate 4-4 in a differential mode. The first capacitance plates of the monitoring electrode plate 4-3 and the differential electrode plate 4-4 are respectively connected to the EXCA excitation pins of the AD7745 chip; the second capacitance plate of the monitoring electrode plate 4-3 is connected to the CIN(+) pin of the AD7745 chip as the positive capacitance input; the second capacitance plate of the differential electrode plate 4-4 is connected to the CIN(-) pin of the AD7745 chip as the negative capacitance input; measuring the fertilization amount in a differential mode can suppress the influence of environmental temperature changes, power fluctuations, and electromagnetic interference on the capacitance value measurement, and can improve the measurement sensitivity. The 5V power supply input by the fertilization amount 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, converts it into a capacitance value, and transmits the capacitance value to the fertilization amount control system 6 using CAN communication through the TJA1050 chip.

[0107] In the embodiment of the present invention, the outer diameter of the fertilizer discharge connecting pipe 4-6 is 35mm. The monitoring electrode plate 4-3 is composed of a pair of circuit boards PCB with dimensions of 50×100mm, the copper-clad area thereon is 40×90mm, and the spacing distance is 40mm. The differential electrode plate 4-4 is composed of a pair of circuit boards PCB with dimensions of 40×50mm, the copper-clad area thereon is 40×45mm, and the spacing distance is 20mm; a solder mask layer is added to the copper-clad side of the circuit boards PCB of the monitoring electrode plate 4-3 and the differential electrode plate 4-4, which not only insulates but also protects the copper foil from oxidation, corrosion, and damage.

[0108] As Figure 4a shown, the fertilization amount control system 6 based on closed-loop control includes an electric control box 6-1, a controller 6-2, a stepping motor 6-3, a stepping motor driver 6-4, a sprocket 6-5, a machine attitude sensor 6-6, a speed radar 6-7, a radar mounting bracket 6-8, and a motor mounting bracket 6-9;

[0109] The electric control box 6-1 is installed on the outer end face of the side plate 1-2 of the fertilizer box 1, and a controller 6-2, a liquid crystal display screen, a stepper motor driver 6-4, a machine attitude sensor 6-6, and a PWM signal amplifier are installed therein; the controller 6-2 is an STM32F407ZGT6 development board, which is connected to the liquid crystal display screen, the PWM signal amplifier, the stepper motor driver 6-4, the machine attitude sensor 6-6, and the speed measurement radar 6-7; the stepper motor 6-3 is fixedly connected to the triangular fixing plate 3-5 through a motor bracket 6-9, and the power output shaft of the stepper motor 6-3 is fixedly connected to the fertilizer discharge shaft at the end of the counter-rotating fertilizer discharge screw 2-3 through a sprocket 6-5 and a 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 through the PWM signal amplifier. The PWM signal amplifier can boost the 3.3V PWM pulse signal output by the IO port of the controller 6-2 to 5V to reach the drive signal voltage range of the stepper motor driver 6-4; the machine attitude sensor 6-6 is connected to the controller 6-2 and is used to monitor the attitude of the wheat fertilizer application device based on closed-loop control. The attitude of the wheat fertilizer application device based on closed-loop control includes the lifted idle state and the lowered working state; the speed measurement radar 6-7 is installed outside the crossbeam sealing plate 3-7 through a radar mounting bracket 6-8 to reduce the influence of machine vibration on radar measurement; the installation height of the speed measurement radar 6-7 is 40 cm, and the angle with the ground is 35°. Since the speed measurement radar 6-7 is very sensitive to any error in the angle with the ground, the radar mounting bracket 6-8 connected by bolts can adjust the angle between the speed measurement radar 6-7 and the ground; the controller 6-2 communicates with the monitoring circuit board 4-2 in the fertilizer application amount monitoring device 4 through the CAN communication protocol to obtain the current actual fertilizer application amount, and communicates with the machine attitude sensor 6-6 through the IIC communication protocol to obtain the current working state of the machine, and obtains the current forward speed of the machine by reading the frequency of the square wave signal fed back by the speed measurement radar 6-7; and adjusts the speed of the stepper motor by outputting PWM signals with different frequencies; and displays a human-machine interaction interface through the liquid crystal display screen.

[0110] As Figure 9 and Figure 10 shown, a wheat fertilizer application adjustment method using the wheat fertilizer application device based on closed-loop control described above includes the following steps:

[0111] S1. System initialization and setting of the fertilizer application amount per mu;

[0112] The controller 6-2 is initialized, the fertilizer application amount monitoring device 4, the machine attitude sensor 6-6, the speed measurement radar 6-7, and the stepper motor 6-3 are started, and the fertilizer application amount per mu is set through the human-machine interaction interface.

[0113] S2. Judging the operating state of the wheat fertilizer application device;

[0114] When the implement attitude sensor 6-6 detects that the wheat fertilizing device is in the lifted idle state, the stepper motor 6-3 is turned off and the fertilizing operation is paused; when the implement attitude sensor 6-6 detects that the wheat fertilizing device is in the lowered working state, the stepper motor 6-3 is started and the fertilizing operation begins;

[0115] S3. Closed-loop regulation of fertilizing amount;

[0116] The controller 6-2 closed-loop adjusts the rotation speed of the stepper motor 6-3 according to the forward speed of the implement measured by the speed radar 6-7, the set fertilizing amount per mu, and the actual fertilizing amount measured by the fertilizing amount monitoring device;

[0117] S3.1. The fertilizing amount monitoring device measures the actual fertilizing amount at the current forward speed of the implement and transmits it to the controller 6-2;

[0118]

[0119]

[0120]

[0121] In Formula 1 to Formula 3, DATA is the actual measured value of the AD7745 chip during the fertilizing amount monitoring process; ε0 is the vacuum dielectric constant, with the unit of pF / mm; V 肥料 is the volume occupied by the fertilizer in the space facing the monitoring electrode plate 4-3, in units of mm 3 ; d 监测 is the distance between the first capacitor electrode plate and the second capacitor electrode plate of the monitoring electrode plate 4-3, in units of mm; ε 肥料 is the relative dielectric constant of the fertilizer; ε 空气 is the relative dielectric constant of air; C is the capacitance value measured by the fertilizing amount monitoring device, in units of pF; 0x800000 is a hexadecimal number, which is the middle value of the chip's capacitance measurement range of -4 pF to 4 pF and the measurement value of 0x000000 to 0xFFFFFF, equivalent to 0 in decimal; Q 实际 is the actual fertilizing amount, in units of g / s;

[0122] Under the action of the counter-rotating double-helix fertilizer distributor 2, the fertilizer falls from the fertilizer box 1 to the monitoring area of the fertilizer application rate monitoring device 4. Since under the same environmental conditions, the capacitance values measured by the monitoring electrode plate 4-3 and the differential electrode plate 4-4 are equal, and the capacitance value measured by the fertilizer application rate monitoring device 4 is the difference between the capacitance values measured by the monitoring electrode plate 4-3 and the differential electrode plate 4-4. When the fertilizer falls to the monitoring area of the fertilizer application rate monitoring device 4, the medium and dielectric constant between the first capacitance electrode plate and the second capacitance electrode plate of the monitoring electrode plate 4-3 change, resulting in a change in the capacitance value measured by the monitoring electrode plate 4-3. At this time, the actual measurement value of the AD7745 chip during the fertilizer application rate monitoring process is calculated by formula 1; furthermore, the capacitance value of the fertilizer passing through the monitoring area can be calculated by formula 2; from formula 1 and formula 2, it can be seen that when the installation position of the monitoring electrode plate is fixed, that is, d 监测 remains unchanged, ε0, ε 肥料 , ε 空气 are constants and do not change either. Therefore, the capacitance value measured by the fertilizer application rate monitoring device 4 during the fertilizer application operation has a linear relationship with the volume of the fertilizer in the space facing the monitoring electrode plate; the fertilizer application rate monitoring device 4 uses the recursive average filtering method for the measured capacitance value data to remove the noise signal or interference signal in the capacitance value data, ensuring the stability and reliability of the measured capacitance value; the capacitance value data obtained under different fertilizer application rates is measured by bench test, and a mathematical model relationship formula, that is, formula 3, is established between the measured capacitance value and the fertilizer application rate. Through the capacitance value measured by the fertilizer application rate monitoring device 4, the actual fertilizer application rate under the current machine forward speed is obtained according to the established mathematical model;

[0123] S3.2. The controller 6-2 combines the set mu fertilizer application rate and calculates the theoretical fertilizer application rate under the current machine forward speed according to formula 4;

[0124]

[0125] In formula 4, Q 理论 is the theoretical fertilizer application rate under the current machine forward speed, with the unit of g / s; M is the set mu fertilizer application rate, with the unit of kg; v is the forward speed of the machine, with the unit of m / s; L is the working width of the machine, L = 2.7m; N is the number of counter-rotating double-helix fertilizer distributors 2, N = 6;

[0126] S3.3. The controller 6-2 compares the actual fertilizer application rate and the theoretical fertilizer application rate under the current machine forward speed. If the actual fertilizer application rate does not match the theoretical fertilizer application rate, the rotation speed of the stepper motor 6-3 is PID controlled according to formula 5;

[0127]

[0128] In formula 5, n is the rotation speed of the stepper motor, with the unit of r / min; Q nThe fertilization amount at the stepping motor speed of n, with the unit of g / s.

[0129] In the example of the present invention, the fertilization amounts at different stepping motor speeds are measured through bench tests, and a mathematical model relationship between the stepping motor speed and the fertilization amount, that is, Formula 5, is established; the controller 6-2 uses the Figure 9 stepping motor control method in to stably and quickly adjust the actual fertilization amount to the size of the theoretical fertilization amount by using PID control, realizing the closed-loop control of the fertilization amount; and finally realizing the uniform and precise fertilization operation.

[0130] The above is only the preferred specific implementation manner of the present invention, but the protection scope of the patent is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A wheat fertilization device based on closed-loop regulation, characterized in that, The wheat fertilizing device includes a frame (3), a fertilizer box (1) installed on the frame (3), a counter-rotating double-helix fertilizer distributor (2), a fertilizer application rate monitoring device (4), a furrow opener (5), and a fertilizer application rate control system (6); The fertilizer box (1) includes a front box body plate (1-1), side plates (1-2), a rear box body plate (1-5), a front inclined bottom plate (1-6), and a rear inclined bottom plate (1-7); the two side plates (1-2) are fixedly connected to both sides of the front box body plate (1-1) and the rear box body plate (1-5); the front inclined bottom plate (1-6) and the rear inclined bottom plate (1-7) are fixedly connected to the bottom ends of the front box body plate (1-1), the rear box body plate (1-5), and the two side plates (1-2), forming a funnel-shaped box bottom; a plurality of pairs of fertilizer outlets (1-8) are arranged at equal intervals along the transverse direction of the machine on the funnel-shaped box bottom; A counter-rotating double-helix fertilizer distributor (2) fixedly connected to the funnel-shaped box bottom is correspondingly arranged below each pair of fertilizer outlets (1-8); The counter-rotating double-helix fertilizer distributor (2) includes a left fertilizer distributor housing (2-1), a right fertilizer distributor housing (2-2), a counter-rotating fertilizer-distributing helix (2-3), and a fertilizer discharge pipe (2-6); the left fertilizer distributor housing (2-1) and the right fertilizer distributor housing (2-2) are hollow cylindrical tubes; the right end of the left fertilizer distributor housing (2-1) is coaxially and fixedly connected to the left end of the right fertilizer distributor housing (2-2) to form a fertilizer distribution chamber; the counter-rotating fertilizer-distributing helix (2-3) is arranged in the fertilizer distribution chamber; the counter-rotating fertilizer-distributing helix (2-3) is composed of two fertilizer-distributing helices with the same structural parameters and opposite helix directions; fertilizer inlets (2-4) corresponding to the fertilizer outlets (1-8) are provided at the tops of both the left fertilizer distributor housing (2-1) and the right fertilizer distributor housing (2-2); a fertilizer discharge port (2-5) is provided at the bottom of the left fertilizer distributor housing (2-1), and the fertilizer discharge port (2-5) is located below the center position of the counter-rotating fertilizer-distributing helix (2-3) and is connected to the fertilizer discharge pipe (2-6); The frame (3) includes a cross beam (3-1), a fertilizer box mounting plate (3-2), a fertilizer box connecting plate (3-3), a fertilizer box supporting beam (3-4), a triangular fixing plate (3-5), a supporting beam support plate (3-6), and a cross beam sealing plate (3-7); the cross beam (3-1) is horizontally arranged below the fertilizer box (1), and a cross beam sealing plate (3-7) is fixedly connected to each end; a pair of fertilizer box mounting plates (3-2) are fixedly connected to the cross beam (3-1); two triangular fixing plates (3-5) are fixedly connected to the side plates (1-2) at the left and right ends of the fertilizer box (1); a pair of supporting beam support plates (3-6) are provided on both the front inclined bottom plate (1-6) and the rear inclined bottom plate (1-7); two fertilizer box supporting beams (3-4) are arranged below the front inclined bottom plate (1-6) and the rear inclined bottom plate (1-7) and are fixedly connected to the triangular fixing plates (3-5) and the supporting beam support plates (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); a plurality of fertilizer application and furrow opening devices (5) corresponding to the counter-rotating double-helix fertilizer distributors (2) one by one are fixedly connected to the cross beam (3-1); The fertilizer application and ditching implement (5) includes a ditching implement main body (5-1), a reflective fertilizer application pipe (5-3), and a ditching implement plowshare (5-4); the ditching implement main body (5-1) is fixedly connected to the cross beam (3-1); the ditching implement plowshare (5-4) is installed at the front part of the bottom end of the ditching implement main body (5-1); the reflective fertilizer application pipe (5-3) is fixedly connected to the rear end face of the ditching implement main body (5-1), and the fertilizer application opening at the bottom end of the reflective fertilizer application pipe (5-3) is located at the rear part of the bottom end of the ditching implement main body (5-1). A fertilizer application amount monitoring device (4) is provided between the reflective fertilizer application pipe (5-3) of each fertilizer application and ditching implement (5) and the fertilizer discharge pipe (2-6) of the corresponding counter-rotating double-helix fertilizer distributor (2). The fertilizer application amount monitoring device (4) includes a housing (4-1), a monitoring circuit board (4-2), monitoring electrodes (4-3), differential electrodes (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 housing (4-1). The mounting bracket (4-5) is composed of a rectangular connecting pipe bracket and a rectangular differential electrode bracket fixedly connected in parallel. The rectangular connecting pipe bracket and the rectangular differential electrode 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) vertically passes through the top plate and the bottom plate of the rectangular connecting pipe bracket and the top plate and the bottom plate of the housing (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 distributor (2), and the bottom end is connected to the reflective fertilizer application pipe (5-3) of the fertilizer application and ditching implement (5); the monitoring electrodes (4-3) are fixedly connected to the front end face and the rear end face of the rectangular connecting pipe bracket; the differential electrodes (4-4) are fixedly connected to the inner walls of the left side plate and the right side plate 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 electrodes (4-3) and the differential electrodes (4-4) respectively; the wiring pipe (4-7) is arranged on the bottom plate of the housing (4-1) and is located below the monitoring circuit board (4-2) for leading out the circuit of the monitoring circuit board (4-2) to the fertilizer application amount control system (6). The monitoring circuit board (4-2) includes an STM32F103C8T6 chip, an AD7745 chip, a TJA1050 chip, and an HT7833 chip, and realizes the functions of stably powering the monitoring circuit board (4-2), collecting and processing the capacitance values measured by the monitoring electrode plate (4-3) and the differential electrode plate (4-4), and communicating with the fertilization amount control system (6); the monitoring circuit board (4-2) is connected to the capacitance plates of the monitoring electrode plate (4-3) and the differential electrode plate (4-4) in a differential mode. The first capacitance plate of the monitoring electrode plate (4-3) and the first capacitance plate of the differential electrode plate (4-4) are respectively connected to the EXCA excitation pins of the AD7745 chip; the second capacitance plate of the monitoring electrode plate (4-3) is connected to the CIN(+) pin of the AD7745 chip as the positive capacitance input; the second capacitance plate of the differential electrode plate (4-4) is connected to the CIN(-) pin of the AD7745 chip as the negative capacitance input; the 5V power supply input by the fertilization amount control system (6) powers the monitoring circuit board (4-2) through capacitance filtering and the HT7833 chip. The STM32F103C8T6 chip reads the data values measured by the AD7745 chip, converts them into capacitance values, and transmits the capacitance values to the fertilization amount control system (6) using CAN communication through the TJA1050 chip; The fertilization amount control system (6) includes an electric control box (6-1), a controller (6-2), a stepping motor (6-3), a stepping motor driver (6-4), a sprocket (6-5), a machine attitude sensor (6-6), a speed measurement radar (6-7), a radar mounting bracket (6-8), and a motor mounting bracket (6-9); The electric control box (6-1) is installed on the outer end face of the side plate (1-2) of the fertilizer box (1), and a controller (6-2), a liquid crystal display screen, a stepper motor driver (6-4), a tool attitude sensor (6-6) and a PWM signal amplifier are installed therein; the controller (6-2) is an STM32F407ZGT6 development board, which is connected to the liquid crystal display screen, the PWM signal amplifier, the stepper motor driver (6-4), the tool attitude sensor (6-6) and the speed measurement radar (6-7); the stepper motor (6-3) is fixedly connected to the triangular fixing plate (3-5) through a motor bracket (6-9), and the power output shaft of the stepper motor (6-3) is fixedly connected to the fertilizer discharge shaft at the end of the counter-rotating fertilizer discharge screw (2-3) through a sprocket (6-5) and a 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) through a PWM signal amplifier. The PWM signal amplifier can boost the 3.3V PWM pulse signal output by the IO port of the controller (6-2) to 5V to reach the driving signal voltage range of the stepper motor driver (6-4); the tool attitude sensor (6-6) is connected to the controller (6-2) and is used to monitor the attitude of the wheat fertilizer application device based on closed-loop control. The attitude of the wheat fertilizer application device based on closed-loop control includes the lifted idle state and the lowered working state; the speed measurement radar (6-7) is installed outside the crossbeam sealing plate (3-7) through a radar mounting bracket (6-8); the controller (6-2) communicates with the monitoring circuit board (4-2) in the fertilizer application amount monitoring device (4) through the CAN communication protocol to obtain the current actual fertilizer application amount, and communicates with the tool attitude sensor (6-6) through the IIC communication protocol to obtain the current working state of the tool, and obtains the current forward speed of the tool by reading the frequency of the square wave signal fed back by the speed measurement radar (6-7); and adjusts the speed of the stepper motor by outputting PWM signals with different frequencies; and displays a human-machine interaction interface through the liquid crystal display screen.

2. The wheat fertilization device based on closed-loop regulation according to claim 1, characterized in that, There are two box body support plates (1-3) between the front box body plate (1-1) and the rear box body plate (1-5) to make the structure of the fertilizer box body stable; there are at least two residual fertilizer outlets (1-4) 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 regulation according to claim 1, characterized in that, The total length L of the counter-rotating fertilizer discharge screw (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 pitch S of the spiral blade is 30mm, the root fillet radius r is 2mm, and the combined angle ɑ of the two sections of fertilizer discharge screws is -148°; the length l of the fertilizer discharge port (2-5) at the bottom of the left fertilizer discharge housing (2-1) is 70mm.

4. The wheat fertilization device based on closed-loop regulation according to claim 1, wherein, The end cross-section of the shaft of the counter-rotating fertilizer discharge screw (2-3) is square and is connected to the square fertilizer discharge shaft as the power input.

5. The wheat fertilization device based on closed-loop regulation according to claim 1, characterized in that, A guard plate (5-2) is provided on the front end face of the opener body (5-1), and the guard plate (5-2) is located above the opener plowshare (5-4).

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

7. The wheat fertilization device based on closed-loop regulation according to claim 1, characterized in that, The outer shell (4-1) is fixedly installed on the upper end surface of the cross beam (3-1) through bolts, and the material of the outer shell (4-1) is metal; the monitoring electrode plate (4-3) and the differential electrode plate (4-4) are fixedly glued on the mounting bracket (4-5); the mounting bracket (4-5) is made of steel plate; an insulating layer is provided at the bottom of the monitoring circuit board (4-2), and it is fixedly installed on the mounting bracket (4-5) through screws. The mounting bracket (4-5) is fixedly connected with the outer shell (4-1) through bolts, and the GND through hole on the monitoring circuit board (4-2) is grounded with the whole fertilizer application amount monitoring device (4) through screws.

8. The wheat fertilization device based on closed-loop regulation according to claim 1, characterized in that, The outer diameter of the fertilizer discharge connecting pipe (4-6) is 35 mm; the monitoring electrode plate (4-3) is composed of a pair of circuit board PCBs of 50×100 mm, the copper-clad area on it is 40×90 mm, and the interval distance is 40 mm; the differential electrode plate (4-4) is composed of a pair of circuit board PCBs of 40×50 mm, the copper-clad area on it is 40×45 mm, and the interval distance is 20 mm; a solder mask layer is provided on the copper-clad side of the circuit board PCBs of the monitoring electrode plate (4-3) and the differential electrode plate (4-4).

9. The wheat fertilization device based on closed-loop regulation according to claim 1, characterized in that, The installation height of the speed measurement radar (6-7) is 40 cm, and the included angle with the ground is 35°.

10. A wheat fertilization adjustment method using the wheat fertilization device based on closed-loop regulation according to any one of claims 1-9, characterized in that, The wheat fertilizer application adjustment method includes the following steps: S1. System initialization and setting of the fertilizer application amount per mu; The controller (6-2) is initialized, the fertilizer application amount monitoring device (4), the machine attitude sensor (6-6), the speed measurement radar (6-7) and the stepping motor (6-3) are started, and the fertilizer application amount per mu is set through the human-computer interaction interface. S2. Judging the operation state of the wheat fertilizer application device; When the machine attitude sensor (6-6) monitors that the wheat fertilizer application device is in the lifted idle state, the stepping motor (6-3) is turned off and the fertilizer application operation is paused; when the machine attitude sensor (6-6) monitors that the wheat fertilizer application device is in the lowered working state, the stepping motor (6-3) is started and the fertilizer application operation begins. S3. Closed-loop regulation of the fertilizer application amount; The controller (6-2) closed-loop adjusts the rotation speed of the stepping motor (6-3) according to the forward speed of the machine measured by the speed measurement radar (6-7), the set fertilizer application amount per mu and the actual fertilizer application amount measured by the fertilizer application amount monitoring device. S3.

1. The fertilizer application amount monitoring device measures the actual fertilizer application amount at the current forward speed of the machine and transmits it to the controller (6-2); In Formulas 1 to 3, DATA is the actual measured value of the AD7745 chip during the monitoring of the fertilization amount; ε0 is the permittivity of vacuum medium, with the unit of pF / mm; V 肥料 is the volume occupied by the fertilizer in the space directly opposite to the monitoring electrode plate (4-3), in unit of mm 3 ; d 监测 is the spacing distance between the first and second capacitor plates of the monitoring electrode plate (4-3), in mm; ε 肥料 is the relative dielectric constant of the fertilizer; ε 空气 is the relative dielectric constant of air; C is the capacitance value measured by the fertilizer application rate monitoring device, in pF; 0x800000 is a hexadecimal number, which is the middle value of the capacitance measurement range of the chip from -4 pF to 4 pF and the measurement values from 0x000000 to 0xFFFFFF, equivalent to 0 in decimal; Q 实际 is the actual fertilizer application rate, in g / s; S3.

2. The controller (6-2) combines the set fertilizer application amount per mu and calculates the theoretical fertilizer application amount at the current forward speed of the machine according to formula 4; In Formula 4, Q 理论 is the theoretical fertilization amount at the current forward speed of the implement, with the unit of g / s; M is the set fertilization amount per mu, with the unit of kg; v is the forward speed of the implement, with the unit of m / s; L is the working width of the implement, with the unit of m; N is the number of the counter-rotating double-helix fertilizer distributors (2). S3.

3. The controller (6-2) compares the actual fertilizer application amount and the theoretical fertilizer application amount at the current forward speed of the machine. If the actual fertilizer application amount does not match the theoretical fertilizer application amount, the rotation speed of the stepping motor (6-3) is PID controlled according to formula 5. In Equation 5, n is the rotational speed of the stepper motor, with the unit of r / min; Q n is the fertilization rate when the rotational speed of the stepper motor is n, with the unit of g / s.

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