Self-operation variable pesticide application pressure stabilizing system and control method

Abstract

According to the self-operation variable pesticide application pressure stabilizing system and the control method, through self-operation testing of the characteristics of the adjusting valve and the spray head electromagnetic valve, the relation between all parameters is obtained in real time; the system automatically runs to obtain the reference flow of the pesticide applying pipeline, and the parameters of the pesticide applying pump and the backwater flow are not required to be known, so that the control program is greatly simplified and errors are reduced; the opening degree of the regulating valve is determined through the flow of each variable nozzle and the regulating valve, the system directly assigns a value to the regulating valve, and the system pressure can be quickly stabilized when the flow of each grid changes; and meanwhile, the opening degree deviation of each grid is recorded, self-learning correction is carried out, and adjustment is more accurate. The problems that in the variable pesticide application technology, the pressure stabilizing time is long, the pressure fluctuation is large, and the characteristics and parameters of control equipment cannot be automatically tested and corrected are solved, good economic value and social value are achieved, and good application prospects are achieved.

Description

Technical Field

[0001] The present invention belongs to the field of agricultural plant protection machinery, and particularly relates to a self-running variable application pressure stabilizing system and a control method therefor. Background Art

[0002] With the development of technology and the improvement of environmental protection requirements, variable application technology has become an important development direction of plant protection technology. Variable application can achieve precise spraying on demand, and has the advantages of improving the utilization rate of pesticides, reducing pesticide residues, and reducing environmental pollution. The variable flow rate spraying system based on pulse width modulation (PWM) technology adjusts the actual spraying flow rate of the nozzle by changing the signal frequency and duty cycle of the nozzle solenoid valve, and has become the main application method due to advantages such as a wide flow rate adjustment range and stable droplet characteristics. However, during the variable application process, pipeline pressure fluctuations are caused by the opening and closing of some nozzles, pump source pulsation, valve body switching actions, etc., resulting in problems such as poor atomization quality and inaccurate drug dosage that need to be solved urgently. During the operation of the application system, it is necessary to maintain a constant nozzle pressure to ensure accurate application dosage. At the same time, the system pressure magnitude and stability will affect the droplet size and spraying angle. The consistency of the fan-shaped spraying angle is crucial for achieving ideal overlap of adjacent nozzles and maintaining uniform coverage. Therefore, the pressure stability of the application system is a key performance index to ensure the spraying effect.

[0003] Currently, the main method for controlling the pressure stability of the variable application system is to measure the characteristics of the application pump, solenoid valve nozzle, and regulating valve through prior experiments, and then perform pressure control according to the flow rate during actual operation. However, during actual operation, the pressure stabilizing time is long and the pressure fluctuation is large. In addition, during the operation of the application system, the characteristics of these three devices will change greatly due to factors such as wear, blockage, and return water flow rate changes, resulting in large pressure deviations and making the system unable to operate normally. Therefore, it is necessary to automatically test the characteristics of each component during operation, calibrate the flow rate of the main pipeline during each operation, and not rely on the characteristics of the pump, while being able to correct the errors during operation. Summary of the Invention

[0004] In view of the deficiencies in the prior art, the present invention provides a self-running variable application pressure stabilizing system and a control method therefor, so as to solve the problems of long pressure stabilizing time, large pressure fluctuation, and inability to automatically test and correct the characteristics and parameters of control devices in the existing variable application technology.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] In the first aspect, the present invention provides a self-running variable application pressure stabilizing system, including: a variable application system, a pressure stabilizing system, and a control system, wherein the control system controls the operation of the variable application system and the pressure stabilizing system;

[0007] The variable application system includes variable nozzles, nozzle solenoid valves, application pipelines, PWMMM controllers, pressure gauges, safety overflow valves, return water mixing valves, application pumps, and medicine tanks; several of the variable nozzles are connected to the application pipelines through corresponding nozzle solenoid valves, and the opening and closing of the nozzle solenoid valves are controlled by PWM controllers; the medicine tank is connected to the application pipeline through an application pump; a pressure gauge, a safety overflow valve, and a return water mixing valve are also installed on the application pipeline, and the return water mixing valve is used to control the return of the liquid medicine to the medicine tank;

[0008] The voltage stabilizing system includes regulating valves, flow meters, and pressure sensors; several of the regulating valves are connected to the application pipeline with tees, and the outlets of the regulating valves are connected to the medicine tank; the flow meters and pressure sensors are installed on the application pipeline.

[0009] Optionally, the variable application system further includes a touch screen, a power distribution device, and a power supply; the touch screen is used for user input and display; the power distribution device is used for power distribution; the power supply is used for power supply.

[0010] Optionally, the variable application system further includes a primary filter and a secondary filter; the primary filter is located between the medicine tank and the application pump, and the secondary filter is located at the outlet of the application pump.

[0011] Optionally, the control system receives operation information, calculates the duty cycle of the nozzle solenoid valve corresponding to each variable nozzle in each grid, and sends it to the PWM controller, and at the same time controls the regulating valve to keep the pressure of the application pipeline constant; wherein, the grid refers to the basic application unit divided according to the operation information.

[0012] In a second aspect, the present invention provides a control method for a self-operating variable application voltage stabilizing system based on the first aspect, including the following steps:

[0013] Step 1: Determine the relationship between the flow rate of the regulating valve, the pressure of the application pipeline, and the opening degree of the regulating valve;

[0014] Step 2: Determine the relationship between the flow rate of the variable nozzle, the frequency and duty cycle of the nozzle solenoid valve, and the pressure of the application pipeline;

[0015] Step 3: Calculate the reference flow rate of the application pipeline under the condition of constant pressure;

[0016] Step 4: The control system calculates the flow rate of each variable nozzle during the operation of each grid, and combines the reference flow rate calculated in Step 3 and the relationships determined in Step 1 and Step 2 to obtain the flow rate, opening degree of the regulating valve, and duty cycle of the nozzle solenoid valve during operation; during the operation of each grid, the PWM controller controls the operation of the nozzle solenoid valve according to the duty cycle of the nozzle solenoid valve, the control system selects the number of opened regulating valves according to the flow rate of the regulating valve, and assigns values to the regulating valves in stages according to the opening degree of the regulating valve;

[0017] Step 5: After starting and running, the variable nozzles perform spraying operations in sequence according to the divided grids; when running in the current grid, the control system calculates in advance the flow rate, opening degree of the regulating valve, and duty cycle of the nozzle solenoid valve based on the flow rate of each variable nozzle in the next grid for use in the operation of the next grid;

[0018] Step 6: During the running stage, when the pressure of the pesticide application pipeline is stable within the set range, correct the opening degree of the regulating valve during the operation of the next grid according to the difference between the calculated opening degree and the actual opening degree of the regulating valve in the current grid;

[0019] Step 7: After completing the spraying operations for each grid, stop running and assign the opening degree corresponding to the reference flow rate to the regulating valve.

[0020] Optionally, step 1 includes:

[0021] Close the nozzle solenoid valve, open the return water stirring valve, start the pesticide application pump, and gradually change the opening degree of the regulating valve from small to large by PID control so that the pressure of the pesticide application pipeline reaches multiple set pressures in sequence, and record the flow rate of the regulating valve each time through the flow meter;

[0022] Through data fitting, the relationship between the flow rate of the regulating valve, the pressure of the pesticide application pipeline, and the opening degree of the regulating valve is as follows:

[0023] Q 阀 =f 1 (p, k);

[0024] k=f 2 (Q 阀 , p);

[0025] In the formula, Q 阀 is the flow rate of the regulating valve, p is the pressure of the pesticide application pipeline, k is the opening degree of the regulating valve, and f 1 and f 2 are relationship functions.

[0026] Optionally, step 2 includes:

[0027] Start the pesticide application pump, open the nozzle solenoid valve, the nozzle solenoid valve operates in PWM mode, and gradually change the opening degree of the regulating valve from small to large by PID control so that the pressure of the pesticide application pipeline reaches multiple set pressures in sequence, and record the flow rate of the regulating valve each time through the flow meter;

[0028] Through data fitting, the relationship between the flow rate of the variable nozzle, the frequency of the nozzle solenoid valve, the duty cycle, and the pressure of the pesticide application pipeline is as follows:

[0029] Q 喷 =f 3 (f, d, p);

[0030] d=f4 (f, d, p);

[0031] Wherein, Q 喷 is the flow rate of the variable nozzle, f and d are respectively the frequency and duty cycle when the nozzle solenoid valve operates with PWM, p is the pressure of the pesticide application pipeline, and f 3 and f 4 are relationship functions.

[0032] Optionally, step 3 includes:

[0033] Close the nozzle solenoid valve, control the opening of the regulating valve by PID. When the pressure of the pesticide application pipeline reaches the stable state of the set pressure, obtain the opening k 0 ;

[0034] Assign the opening k 0 -0.5 to the regulating valve, maintain for a set time, and then control the opening of the regulating valve by PID. When the pressure of the pesticide application pipeline reaches the stable state of the set pressure, record the opening k of the regulating valve, and calculate the reference flow rate according to the opening k as:

[0035] Q 基 = f 1 (p, k);

[0036] Wherein, Q 基 is the reference flow rate, and f 1 is the relationship function between the flow rate of the regulating valve and the pressure p of the pesticide application pipeline and the opening k of the regulating valve.

[0037] Optionally, step 4 includes:

[0038] The control system calculates the flow rate Q of each variable nozzle when running in each grid 喷 , and calculates the flow rate of the regulating valve during operation as:

[0039]

[0040] Wherein, Q 阀 is the flow rate of the regulating valve when the pressure of the pesticide application pipeline reaches the set pressure during operation, Q 基 is the reference flow rate, and n is the number of variable nozzles;

[0041] Obtain the opening of the regulating valve during operation from k = f 2 (Q 阀 , p), and f 2 is the relationship function between the opening k of the regulating valve and the flow rate Q 阀 of the regulating valve and the pressure p of the pesticide application pipeline;

[0042] Obtain d from d = f 4 (f, Q 喷, p) Calculate the duty cycle of each nozzle solenoid valve during operation, f 4 is the relationship function between the duty cycle d of the nozzle solenoid valve, the frequency f of the nozzle solenoid valve, the variable nozzle flow rate Q 喷 , and the pressure p of the spraying pipeline;

[0043] During the operation of each grid, the PWM controller controls the operation of the nozzle solenoid valve according to the duty cycle of the nozzle solenoid valve; the control system calculates Q 阀 The ratio to the maximum flow rate of a single regulating valve is taken as an integer N after rounding. N regulating valves are opened with the maximum flow rate of a single regulating valve, and the other 1 regulating valve is assigned an opening degree of k - 0.5, and t is maintained 1 After that, it is adjusted to be assigned k and maintained for t 2 , t 1 and t 2 are set times less than 1 s; if the pressure of the spraying pipeline is within the range of p ± 0.01, the assigned value remains unchanged. If the pressure of the spraying pipeline exceeds the range, PID control of the regulating valve is started until the pressure of the spraying pipeline is within the range of p ± 0.01.

[0044] Optionally, step 6 includes:

[0045] During the operation stage, when the pressure of the spraying pipeline is stable within the range of p ± 0.01, record the difference k 计 between the calculated opening degree k 实 of the regulating valve and the actual opening degree k 差 = k 实 - k 计 , and correct the opening degree of the regulating valve to k = k 计 + k 差 during the operation of the next grid;

[0046] After the operation of multiple grids, the difference in the opening degree of the regulating valve is averaged for the last 10 times, and the average value is used to correct the opening degree of the regulating valve during the operation of the next grid.

[0047] The beneficial effects of the present invention are as follows: Through the self-running test of the characteristics of the regulating valve and the solenoid valve nozzle, the relationship between various parameters is obtained in real time; the reference flow rate of the spraying pipeline is obtained through the automatic operation of the system, without knowing the parameters of the spraying pump and the return water flow rate, which greatly simplifies the control program and reduces errors; the opening degree of the regulating valve is determined by calculating the flow rate of each nozzle and regulating valve, and the system directly assigns a value to the regulating valve, and the system pressure can be quickly stabilized (less than 1 s) when the flow rate changes in each grid; at the same time, the opening degree deviation of each grid is recorded and self-learned and corrected to make the adjustment more accurate. The present invention solves the problems of long voltage stabilization time, large pressure fluctuation, and inability to automatically test and correct the characteristics and parameters of control equipment in variable spraying technology through the above methods, has good economic value and social value, and has good application prospects. Brief Description of the Drawings

[0048] Figure 1 It is the composition schematic diagram of the self-running variable application pressure stabilizing system of the present invention.

[0049] Figure 2 It is the control flowchart of the self-running variable application pressure stabilizing system of the present invention.

[0050] Figure 3 It is the variable application pressure change curve of the present invention.

[0051] Figure 4 It is the comparison diagram of the pressure stabilizing effect of the present invention.

[0052] The reference numerals in the drawings are: 1, variable nozzle; 2, nozzle solenoid valve; 3, application pipeline; 4, PWM controller; 5, control system; 6, touch screen; 7, power distribution device; 8, power supply; 9, regulating valve; 10, flow meter; 11, pressure sensor; 12, pressure gauge; 13, safety overflow valve; 14, return water stirring valve; 15, secondary filter; 16, application pump; 17, primary filter; 18, medicine tank. Detailed Description of the Invention

[0053] Now, the present invention will be further described in detail with reference to the drawings.

[0054] Embodiment 1

[0055] This embodiment provides a self-running variable application pressure stabilizing system, as Figure 1 shown, which includes a variable application system, a pressure stabilizing system and a control system. The variable application system consists of a variable nozzle 1, a nozzle solenoid valve 2, an application pipeline 3, a PWM controller 4, a touch screen 6, a power distribution device 7, a power supply 8, a pressure gauge 12, a safety overflow valve 13, a return water stirring valve 14, a secondary filter 15, an application pump 16, a primary filter 17, a medicine tank 18, etc.; the pressure stabilizing system consists of a regulating valve 9, a flow meter 10, a pressure sensor 11, etc.

[0056] In the variable application system, the variable nozzle 1 and the nozzle solenoid valve 2 are connected by a pipeline to spray the liquid medicine onto the field at a certain flow rate and particle size to prevent and control pests and diseases. The nozzle solenoid valve 2 is respectively connected to the variable nozzle 1 and the application pipeline 3, and controls the liquid medicine spraying of the variable nozzle 1 by opening and closing. The working mode is PWM, and the working frequency is generally 10 - 30 Hz. The application pipeline 3 is connected to the application pump 16, the nozzle solenoid valve 2, and the variable nozzle 1, and is responsible for transporting the liquid medicine with a certain pressure. The application pump 16 is connected to the application pipeline 3 and the medicine tank 18, and is used to pressurize the liquid medicine and transport it through the application pipeline 3 to the variable nozzle 1 for spraying onto the field. The medicine tank 18 is used to store the prepared liquid medicine. The pressure gauge 12 is installed on the application pipeline 3 to display the pressure of the application pipeline. The return water mixing valve 14 is installed on the application pipeline 3 at the outlet of the application pump 16 to control a part of the liquid medicine to flow back to the medicine tank 18 to stir the liquid medicine, making the liquid medicine more uniform. The primary filter 17 is located between the medicine tank 18 and the application pump 16 and is used to perform primary filtration on the liquid medicine. The secondary filter 15 is located at the outlet of the application pump 16 to perform fine filtration on the liquid medicine, with a precision greater than 80 mesh, to prevent blockage of the solenoid valve, nozzle, etc. The safety overflow valve 13 is installed on the application pipeline 3 and is used to automatically open and relieve pressure when the pipeline pressure exceeds the set value (generally 0.5 MPa) to ensure the safety of each component of the application system.

[0057] The control system is respectively connected to the PWM controller 4, the touch screen 6, the power distribution device 7, the regulating valve 9, the flow meter 10, and the pressure sensor 11 through control cables, collects the information of each sensor, receives real-time or prescription map operation information, calculates the duty cycle of each variable nozzle 1 corresponding to the nozzle solenoid valve 2 in the grid, and sends it to the PWM controller 4. At the same time, it controls the regulating valve 9 to quickly maintain the set pressure value constant. Among them, the prescription map is made before the operation, the real-time operation information refers to the processed information collected by the on-board camera, etc., and the grid is the basic application unit divided by the prescription map.

[0058] The PWM controller 4 is connected to the control system, receives the nozzle solenoid valve switching frequency and duty cycle parameters sent by the control system, and controls the operation of the nozzle solenoid valve 2. The touch screen 6 is used for users to input setting information and display the control interface and real-time data. The power supply 8 is used to provide energy for each electrical device in the system. The power distribution device 7 is used to distribute power to each device and play a protective role.

[0059] In the voltage stabilizing system, the regulating valve 9 is connected to the application pipeline 3 with a tee, and the outlet is connected to the medicine tank 18, and is used to adjust the pressure of the spraying system. Multiple ones can be installed according to the system flow rate. The flow meter 10 is installed on the application pipeline 3, located between the regulating valve 9, the variable nozzle 1, and the application pump 16, and is used to collect the real-time flow rate. The pressure sensor 11 is installed on the application pipeline 3, located between the regulating valve 9, the variable nozzle 1, and the application pump 16, and is used to collect the real-time pressure of the application pipeline.

[0060] Example 2

[0061] This embodiment proposes a control method for the self - running variable - dosing pressure - stabilizing system based on Embodiment 1. As Figure 2 shown, the method includes the following steps:

[0062] Step 1: Determine the relationship between the flow rate, pressure, and opening of the regulating valve.

[0063] Close the nozzle solenoid valve, manually open the return - water mixing valve to an appropriate opening, start the dosing pump by the control system, and change the opening of the regulating valve from small to large by PID control so that the pipeline pressure reaches the set pressure. Automatically record the flow rate value each time through the flowmeter. The pressure values are taken as 0.2, 0.3, 0.4 MPa, and the opening values are taken from 0 - 100%, with an interval of 5%. Through data fitting, obtain the relationship formulas between the flow rate of the regulating valve, pressure, and opening:

[0064] Q 阀 =f 1 (p, k);

[0065] k = f 2 (Q 阀 , p);

[0066] In the formula, Q 阀 is the flow rate of the regulating valve, L / min; p is the pressure of the dosing pipeline, MPa; k is the opening of the regulating valve, with the minimum value of 0 and the maximum value of 100, which is automatically adjusted to the corresponding opening by an electrical signal. The electrical - signal range is 0 - 10V, %.

[0067] Since small - flow valves have higher adjustment accuracy, when the dosing system has a large flow rate, configure multiple small - flow regulating valves to improve the response speed and accuracy of the system. If there are multiple regulating valves, determine the relationship formulas between the flow rate, pressure, and opening for each regulating valve according to the above process.

[0068] Step 2: Self - running to determine the relationship between the flow rate of the variable nozzle, the frequency and duty cycle of the nozzle solenoid valve, and the pressure of the dosing pipeline.

[0069] Through the self - learning operation of the dosing system, obtain the relationship formulas between the flow rate of the variable nozzle, the frequency and duty cycle of the nozzle solenoid valve, and the pressure of the dosing pipeline.

[0070] The control system starts the chemical pump and opens the nozzle solenoid valve. The nozzle solenoid valve operates in PWM mode, with an operating frequency range of 10 - 30 Hz, an adjustment interval of 5, a duty cycle range of 10 - 90%, an interval of 10, and pressure values of 0.2, 0.3, and 0.4 MPa. The PID control changes the opening of the regulating valve to make the pressure in the chemical application pipeline reach the set pressure. The flowmeter automatically records the flow value each time, and through data fitting, the relationship formula between the variable nozzle flow rate and the frequency, duty cycle of the nozzle solenoid valve, and the pressure in the chemical application pipeline is automatically obtained:

[0071] Q 喷 =f 3 (f, d, p);

[0072] d=f 4 (f, d, p);

[0073] In the formula, Q 喷 is the flow rate of the variable nozzle, L / min; f is the frequency when the nozzle solenoid valve operates in PWM mode, Hz; d is the duty cycle when the nozzle solenoid valve operates in PWM mode, with a minimum of 0 and a maximum of 100, %; p is the pressure in the chemical application pipeline, MPa.

[0074] After the variable nozzle has run for a certain period of time, due to pressure wear or blockage, the aperture size will change, and the flow rate will also change. At this time, run step 2 again to correct the relationship formula between the variable nozzle flow rate and the frequency, duty cycle of the nozzle solenoid valve, and the pressure in the chemical application pipeline.

[0075] Step 3: Automatically calculate the reference flow rate of the chemical application pipeline during self - operation.

[0076] Under the condition of constant pressure, the flow rate through the fixed pipeline is also constant. Since the flow rate of the pump and the return water mixing flow rate will change, the reference flow rate in the chemical application pipeline needs to be calibrated each time it runs or when the flow rate changes.

[0077] During calibration, the nozzle solenoid valve is closed, and the PID control adjusts the opening of the regulating valve. When the set pressure stable state is reached (stable for 5 s within p ± 0.01), the opening k 0 of the regulating valve is obtained. Assign a value of k 0 - 0.5 to the regulating valve and maintain it for 0.1 s. Then, the PID control adjusts the opening of the regulating valve again. When the set pressure stable state is reached (stable for 5 s within p ± 0.01), the opening value k of the regulating valve is obtained, and the reference flow rate is calculated based on this opening value. The reference flow rate formula:

[0078] Q 基 =f 1 (p, k);

[0079] In the formula, Q 基 is the reference flow rate, L / min.

[0080] Step 4: The dosing system starts and operates with rapid pressure stabilization.

[0081] Before variable dosing, the flow rate Q of each variable nozzle during operation is obtained from the prescription map or real-time calculation. 喷 During operation, the flow rate of the regulating valve can be calculated by the following formula:

[0082]

[0083] In the formula, Q 阀 is the flow rate of the regulating valve when the set pressure is reached during operation, in L / min; Q 基 is the reference flow rate obtained from testing, in L / min; Q 喷 is the flow rate of each variable nozzle, in L / min; n is the number of variable nozzles.

[0084] From k = f 2 (Q 阀 , p), the opening value of the regulating valve during operation is calculated.

[0085] From d = f 4 (f, Q 喷 , p), the duty cycle of each nozzle solenoid valve during operation is calculated.

[0086] During operation, the PWM controller controls the operation of the nozzle solenoid valve according to the duty cycle, the variable nozzles perform dosing and spraying, and at the same time, the state of the regulating valve is controlled to achieve rapid pressure stabilization.

[0087] Calculate the ratio of Q 阀 to the maximum flow rate of a single regulating valve, and after rounding, the number N is obtained. The system opens N regulating valves at the maximum flow rate, and at the same time, the calculated opening value k - 0.5 is assigned to another regulating valve. After maintaining for 0.1 s, then assign k and maintain for 0.3 s. If the pressure remains unchanged within the range of p ± 0.01 for the regulating valve, the PID stops. If it exceeds the range, the PID starts and adjusts the pressure to within the range of p ± 0.01.

[0088] Through this step, the pressure of the dosing system can be quickly adjusted to within the range of p ± 0.01 after the variable nozzles are opened, achieving rapid pressure stabilization, and the time is generally less than 1 s.

[0089] Step 5: The spray grid is switched for rapid pressure stabilization.

[0090] After the dosing system starts and operates, it sprays according to the set grid. According to the prescription map or real-time results, the flow rates of the variable nozzles in each grid are different.

[0091] When the current grid is running, given the flow rate of each variable nozzle in the next grid, calculate the flow rate, opening degree of the regulating valve, and duty cycle of each nozzle solenoid valve respectively according to the process in step 4. When reaching the next grid, the PWM controller controls the operation of the nozzle solenoid valve according to the duty cycle, and the variable nozzle sprays pesticides. At the same time, assign the calculated opening degree k - 0.5 to the regulating valve, keep it for 0.1 s, then assign k and keep it for 0.3 s. If the pressure is within the range of p ± 0.01, the regulating valve assignment remains unchanged and the PID stops. If it exceeds the range, the PID starts and adjusts the pressure to within the range of p ± 0.01.

[0092] Keep running in this way in a loop, and the system pressure can be kept stable all the time.

[0093] Step 6: Self-learning opening degree deviation correction.

[0094] During the grid running stage, when the pressure is stable within the range of p ± 0.01, record the opening degree k of the regulating valve calculated each time 计 and the actual opening degree k 实 The difference k 差 = k 实 - k_calculated, and correct this value at the next grid: k = k 计 + k 差 . Among them, the actual opening degree refers to the opening degree adjusted by the PID when reaching the steady state, and the calculated opening degree is the opening degree calculated according to the flow rate and assigned. After assignment, the pressure is not necessarily the set pressure. At this time, the PID will adjust to the set pressure and there will be a corresponding opening degree.

[0095] After running in multiple grids, take the average of the last 10 times of the opening degree difference of the regulating valve, and use the average value to correct the opening degree of the regulating valve when running in the next grid.

[0096] By this method, the pressure value deviation is smaller, closer to the set value, and the voltage stabilizing effect is better.

[0097] Step 7: Quick voltage stabilization when stopping running.

[0098] When the pesticide application system stops running, if the regulating valve is not controlled in a timely and accurate manner, the system pressure will rise sharply, causing system damage. Therefore, when stopping spraying, assign the opening degree corresponding to the reference flow rate to the regulating valve, so that the system pressure can be quickly stabilized at the set pressure p.

[0099] In the specific application process of this embodiment, the variable pesticide application pressure change curve is as Figure 3 shown, and the voltage stabilizing effect is as Figure 4 shown. It can be seen from this that compared with the non-voltage stabilization measures or the existing voltage stabilization technologies, the control method proposed in this embodiment has a short voltage stabilization time and small pressure fluctuation, and has the function of automatically testing and correcting specific parameters, and has good application prospects.

[0100] The above are only the preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions falling within the concept of the present invention belong to the protection scope of the present invention. It should be noted that for those of ordinary skill in the art, several improvements and refinements made without departing from the principle of the present invention should be regarded as within the protection scope of the present invention.

Claims

1. A self-operating variable-rate pesticide application and pressure stabilization system, characterized in that: include: A variable-rate application system, a voltage stabilization system and a control system, wherein the control system controls the operation of the variable-rate application system and the voltage stabilization system; The variable spraying system comprises a variable spray head (1), a spray head electromagnetic valve (2), a spraying pipeline (3), a PWM controller (4), a pressure gauge (12), a safety overflow valve (13), a return water stirring valve (14), a spraying pump (16) and a medicine box (18); a plurality of the variable spray heads (1) are connected to the spraying pipeline (3) via corresponding spray head electromagnetic valves (2), and the spray head electromagnetic valves (2) are controlled to open and close via the PWM controller (4); the medicine box (18) is connected to the spraying pipeline (3) via the spraying pump (16); the spraying pipeline (3) is also equipped with a pressure gauge (12), a safety overflow valve (13) and a return water stirring valve (14), and the return water stirring valve (14) is used to control the return of the medicine solution to the medicine box (18); The pressure stabilizing system comprises a regulating valve (9), a flow meter (10) and a pressure sensor (11); a plurality of the regulating valves (9) are connected to a drug application pipeline (3) by means of a tee, and the outlet of the regulating valve (9) is connected to a medicine box (18); the flow meter (10) and the pressure sensor (11) are installed on the drug application pipeline (3).

2. A self-operating variable-rate pesticide application and pressure-stabilizing system as claimed in claim 1, characterized in that: The variable-variable dosage system further comprises a touch screen (6), a power distribution device (7) and a power supply (8); the touch screen (6) is used for user input and display; the power distribution device (7) is used for distributing power; and the power supply (8) is used for supplying power.

3. A self-operating variable-rate pesticide application and pressure-stabilizing system as claimed in claim 1, characterized in that: The variable-volume drug application system further comprises a primary filter (17) and a secondary filter (15); the primary filter (17) is located between the drug box (18) and the drug application pump (16), and the secondary filter (15) is located at the outlet of the drug application pump (16).

4. A self-operating variable-rate pesticide application and pressure-stabilizing system as claimed in claim 1, characterized in that: The control system receives operation information, calculates the duty cycle of the nozzle solenoid valve (2) corresponding to each variable nozzle (1) in each grid, and sends it to the PWM controller (4), while controlling the regulating valve (9) to keep the pressure of the drug application pipeline (3) constant; wherein the grid refers to a basic drug application unit divided according to the operation information.

5. A control method based on the self-operating variable-rate pesticide application and pressure-stabilizing system as claimed in claim 4, characterized in that: The steps include: Step 1: Determine the relationship between the regulating valve flow rate, the application pipeline pressure, and the regulating valve opening; Step 2: Determine the relationship between the variable nozzle flow rate and the nozzle solenoid valve frequency, duty cycle and application pipeline pressure; Step 3: Calculate the baseline flow rate of the application pipeline under constant pressure; Step 4: The control system calculates the flow rate of each variable nozzle when each grid is running, and combines the reference flow rate calculated in step 3 and the relationship determined in steps 1 and 2 to obtain the flow rate, opening degree and duty cycle of the control valve during operation; when each grid is running, the PWM controller controls the operation of the control valve according to the duty cycle of the control valve, and the control system selects the opening number of the control valve according to the flow rate of the control valve, and assigns the control valve in stages according to the opening degree of the control valve; Step 5: After starting the operation, the variable nozzles perform spraying operations in sequence according to the divided grids; when the current grid is running, the control system calculates the flow rate, opening degree and duty cycle of the regulating valve and the nozzle solenoid valve in advance according to the flow rate of each variable nozzle in the next grid, which are used for the operation of the next grid; Step 6: During the operation phase, when the pressure in the application pipeline is stable within the set range, the opening of the regulating valve calculated in the current grid and the actual opening are used to correct the opening of the regulating valve during the next grid operation; Step 7: After completing the spraying operation of each grid, stop the operation and assign the opening corresponding to the reference flow to the regulating valve.

6. The control method according to claim 5, characterized in that: The step 1 comprises: Close the nozzle solenoid valve, open the return water stirring valve, start the application pump, and use PID control to change the opening of the regulating valve from small to large, so that the pressure in the application pipeline reaches multiple set pressures in sequence, and the flow rate of the regulating valve is recorded each time through the flow meter; After data fitting, the relationship between the regulating valve flow rate, the application pipeline pressure, and the regulating valve opening is as follows: Q 阀 =f1(p,k); k=f2(Q 阀 ,p); In the formula, Q 阀 is the flow rate of the regulating valve, p is the pressure of the application pipeline, k is the opening of the regulating valve, and f1 and f2 are relationship functions.

7. The control method according to claim 5, characterized in that: The step 2 comprises: Start the spray pump and open the spray head solenoid valve. The spray head solenoid valve operates in PWM mode. The PID control changes the opening of the regulating valve from small to large, so that the pressure in the spray pipe reaches multiple set pressures in sequence. The flow meter records the flow of the regulating valve each time. After data fitting, the relationship between the variable nozzle flow rate and the nozzle solenoid valve frequency, duty cycle and application pipeline pressure is as follows: Q 喷 =f3(f,d,p); d = f4(f, d, p); In the formula, Q 喷 is the flow rate of the variable nozzle, f and d are the frequency and duty cycle of the nozzle solenoid valve PWM operation, p is the pressure of the application pipeline, and f3 and f4 are relationship functions.

8. The control method according to claim 5, characterized in that: The step 3 comprises: Close the nozzle solenoid valve, and use PID to control the opening of the regulating valve. When the pressure in the application pipeline reaches the stable state of the set pressure, the opening k0 of the regulating valve is obtained; Assign an opening of k0-0.5 to the regulating valve, maintain the set time, and then use PID to control the opening of the regulating valve. When the pressure in the application pipeline reaches the stable state of the set pressure, record the opening k of the regulating valve. According to the opening k, the reference flow is calculated as: Q 基 =f1(p,k); In the formula, Q 基 is the reference flow rate, f1 is the relationship function between the regulating valve flow rate and the application pipeline pressure p and the regulating valve opening k.

9. The control method according to claim 5, characterized in that: The step 4 comprises: The control system calculates the flow rate Q of each variable nozzle when each grid is running 喷 , and calculate the control valve flow rate during operation as: In the formula, Q 阀 Q is the flow rate of the regulating valve when the pressure of the application pipeline reaches the set pressure during operation. 基 is the base flow rate, n is the number of variable nozzles; From k = f2(Q 阀 , p) calculates the opening of the regulating valve during operation, f2 is the regulating valve opening k and the regulating valve flow Q 阀 , the relationship function between the pressure p of the application pipeline; From d = f4 (f, Q 喷 , p) calculates the duty cycle of each nozzle solenoid valve during operation, f4 is the duty cycle d of the nozzle solenoid valve and the nozzle solenoid valve frequency f, variable nozzle flow Q 喷 , the relationship function between the pressure p of the application pipeline; When each grid is running, the PWM controller controls the operation of the nozzle solenoid valve according to the duty cycle of the nozzle solenoid valve; the control system calculates Q 阀 The ratio of the maximum flow rate of a single regulating valve is rounded to an integer N. N regulating valves are opened at the maximum flow rate of a single regulating valve, and the opening of another regulating valve is assigned with a value of k-0.

5. After maintaining t1, the assigned value is adjusted to k and t2 is maintained. t1 and t2 are set times less than 1s. If the pressure in the application pipeline is within the range of p±0.01, the assigned value is maintained unchanged. If the pressure in the application pipeline exceeds the range, the PID control of the regulating valve is started until the pressure in the application pipeline is within the range of p±0.

01.

10. The control method according to claim 9, characterized in that: The step 6 comprises: During the operation phase, when the pressure in the application pipeline is stable within the range of p±0.01, the opening of the regulating valve k calculated in the current grid operation is recorded. 计 and the actual opening k 实 The difference k 差 =k 实 -k 计 , and correct the control valve opening to k = k when the next grid is running 计 +k 差 ; After multiple grids are run, the most recent 10 averages of the control valve opening differences are taken, and the average value is used to correct the control valve opening when the next grid is run.

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