Variable pesticide application regulation and control method based on leaf density, regulation and control system thereof and spraying machine

Abstract

The invention provides a variable pesticide application regulation and control method based on leaf density, a regulation and control system thereof and a sprayer, and the method comprises the following steps: 1, collecting related parameters in the operation process of the variable pesticide application regulation and control system, and sending the collected related parameters to a central control unit; step 2, according to the relevant parameters acquired in the step 1, calculating the required pesticide application amount in unit volume of a fruit tree canopy in the operation area, fitting the relationship between the flow of a pesticide application spray head and a duty ratio signal, and constructing a variable pesticide application regulation and control model based on duty ratio signal regulation; and 3, calculating a duty ratio signal according to the operation parameters of the regulation and control system obtained in the step 1 and the variable pesticide application regulation and control model in the step 2, and regulating and controlling a flow electromagnetic valve by a central control unit according to the duty ratio signal so as to realize variable pesticide application regulation and control. The device provides a theoretical basis for precise pesticide application control by constructing a'leaf density-pesticide application amount 'regulation and control model, so that the pesticide utilization rate is improved.

Description

Technical Field

[0001] The present invention belongs to the field of precise pesticide application in orchards, and particularly relates to a variable pesticide application regulation method based on leaf density, a regulation system thereof, and a sprayer. Background Art

[0002] Spraying chemical pesticides is the main means for controlling pests and diseases in orchards. However, continuous, extensive, and excessive application has caused serious pesticide waste and environmental pollution, and the effective utilization rate of pesticides is only about 40%. Targeted variable pesticide application based on the characteristics of the fruit tree canopy is an effective means to solve pesticide waste and environmental pollution.

[0003] In related prior arts, Prior Art One (patent publication number CN110506723B) discloses a variable spray control system and method based on the leaf area index of the fruit tree canopy, which can measure the leaf area index by using an ultrasonic sensor module to achieve variable spray control. Prior Art Two (patent publication number CN110476941B) discloses an automatic target variable spray control system, a sprayer, and a control method, which can measure the volume of the tree canopy by using a lidar to achieve variable spray control. Although the above technical solutions can reduce the amount of pesticide application to a certain extent, they all ignore or simplify the asymmetric and porous irregular structure of the tree canopy. Thus, precise pesticide application still cannot be achieved, and there are still problems of pesticide application waste and environmental pollution. Summary of the Invention

[0004] The purpose of the present invention is to solve the problems existing in the above prior arts, and provide a variable pesticide application regulation method based on leaf density, a regulation system thereof, and a sprayer. The device constructs a "leaf density - pesticide application amount" regulation model to provide a theoretical basis for precise pesticide application control, thereby improving the utilization rate of pesticides.

[0005] One of the purposes of the present invention is to provide a variable pesticide application regulation method based on leaf density, including the following steps:

[0006] Step 1: Collect relevant parameters during the operation of the sprayer, and send the collected relevant parameters to the central control unit;

[0007] Step 2: Calculate the amount of pesticide required per unit volume of the fruit tree canopy in the operation area according to the relevant parameters collected in Step 1, fit the relationship between the flow rate of the pesticide spraying nozzle and the duty cycle signal, and construct a variable pesticide application regulation model based on the adjustment of the duty cycle signal;

[0008] Step 3: Calculate the duty cycle signal according to the operation parameters of the sprayer obtained in Step 1 and the variable pesticide application regulation model in Step 2. The central control unit regulates the flow solenoid valve (8) according to the duty cycle signal, thereby realizing variable pesticide application regulation.

[0009] As a preferred solution, in step one, move the sprayer to the operation area, start the sprayer for operation, measure the moving speed of the sprayer, the width and position information of the target fruit tree canopy, the leaf density of the target fruit tree, the distance between the nozzle and the target fruit tree canopy, and the spray pressure of the nozzle, and upload the collected data to the central control unit in real time.

[0010] As a preferred solution, in step two, calculate the amount of medicine required per unit volume of the fruit tree canopy in the operation area based on the relevant parameters collected in step one, which is calculated by the following formula (1):

[0011]

[0012] In the formula, Q1 is the amount of liquid medicine required per unit volume of the fruit tree canopy, n is a constant specified by the low-dose medicine application standard for fruit trees, representing the number of droplets per square meter, ρ favd is the leaf density, C v is a constant related to the nozzle, and P is the spray pressure.

[0013] As a preferred solution, in step two, calculate the amount of medicine required per unit volume of the fruit tree canopy in the operation area based on the relevant parameters collected in step one, and compensate the amount of medicine applied. Fit the relationship between the flow rate of the medicine application nozzle and the duty cycle signal, and construct a variable medicine application control model based on the regulation of the duty cycle signal;

[0014] The amount of liquid medicine required for compensating the amount of medicine applied is calculated by the following formula (2):

[0015]

[0016] In the formula, Q is the amount of liquid medicine sprayed by the nozzle, k is the correction coefficient, δ is a constant greater than 0, L d is the distance between the nozzle and the fruit tree canopy, q is the spray flow rate of the nozzle, L v is the distance traveled by the sprayer within time t, and v is the traveling speed of the sprayer.

[0017] As a preferred solution, in step two, the relationship between the flow rate of the medicine application nozzle and the duty cycle signal is fitted. Under the conditions of a certain pressure and frequency range, the spray flow rate q of the nozzle and the duty cycle x satisfy the linear relationship of formula (3), that is:

[0018] q = ax + b (3)

[0019] In the formula; a and b are constants obtained when deriving the formula for the fitting straight line, and are fitted based on the calibration result of the amount of medicine applied based on the duty cycle.

[0020] As a preferred solution, constructing the variable medicine application control model based on the regulation of the duty cycle signal is to calculate the relationship between the leaf density of the fruit tree and the variable medicine application control signal, which is calculated by the following formula (4):

[0021]

[0022] where x is the duty cycle, n is a constant specified by the low-dose pesticide application standard for fruit trees, k is a correction factor, v is the traveling speed of the sprayer, ρ favd is the leaf density, C v is a constant related to the nozzle, δ is a constant greater than 0, L d is the distance between the nozzle and the fruit tree canopy, P is the spray pressure, L v is the traveling distance of the sprayer within time t, a and b are constants obtained when deriving the formula for the fitting straight line, and a and b are obtained by fitting the calibration results of the pesticide application amount based on the duty cycle.

[0023] As an optimal solution, in the second step, the following test method is adopted to fit the relationship between the flow rate of the pesticide application nozzle and the duty cycle signal to establish a variable pesticide application control model:

[0024] Step 21: Adjust the opening and closing angle of the flow rate solenoid valve, set the opening and closing angle of the first group of tests, and collect the liquid output of the nozzle using a specific container.

[0025] Step 22: Open the flow rate solenoid valve and the pump, continuously collect the water output of the nozzle under a specific spray pressure and within a specific time. When the collection time arrives, close the flow rate solenoid valve and the pump.

[0026] Step 23: After a group of tests, adjust the flow rate solenoid valve to the next opening and closing angle, repeat the above process of collecting the water output of the nozzle. The opening and closing angle of the flow rate solenoid valve increases step by step with a first specific amount, and count the liquid output of the nozzle at a specific opening and closing angle.

[0027] Step 24: According to the liquid output of the nozzle at each specific opening and closing angle of the flow rate solenoid valve counted in Step 23, select a specific opening and closing angle range of the flow rate solenoid valve, and conduct supplementary tests within the specific opening and closing angle range of the flow rate solenoid valve. The supplementary test method is: open the flow rate solenoid valve and the pump, continuously collect the liquid output of the nozzle under a specific spray pressure and within a specific time. When the collection time arrives, close the flow rate solenoid valve and the pump. After a group of tests, adjust to the next opening and closing angle, repeat the above process of collecting the liquid output of the nozzle. The opening and closing angle of the flow rate solenoid valve increases with a second specific amount, and count the liquid output of the nozzle at this opening and closing angle. The value of the second specific amount is less than the value of the first specific amount.

[0028] The second object of the present invention is to provide a variable application regulation system based on leaf density, which includes a data acquisition unit, a central control unit, a target execution mechanism, and a variable application unit. The data acquisition unit is signal-connected to the central control unit. The data acquisition unit includes a lidar, a leaf density detection module, and an ultrasonic sensor. The lidar is used to detect the canopy width and position information of the target fruit tree; the leaf density detection module is used to measure the leaf density information of the canopy of the target fruit tree, and the ultrasonic sensor is used to measure the distance from the nozzle to the canopy of the target fruit tree;

[0029] The central control unit is respectively signal-connected to the target execution mechanism and the variable application unit, and is used to receive the data information of the data acquisition unit, calculate the application amount according to the collected data information, and send control instructions to the target execution mechanism and the variable application unit according to the application amount;

[0030] The target execution mechanism is used to control and adjust the height and spray angle of the nozzle;

[0031] The variable application unit is used to control the spray flow rate of the nozzle.

[0032] As a preferred solution, the variable application unit includes a pump, a flow solenoid valve, a pressure sensor, and a flow meter; the pump, the flow regulating valve, the pressure sensor, and the flow meter are arranged on the application connection pipeline. The pressure sensor is used to measure the spray pressure of the nozzle, the flow meter is used to obtain the spray flow rate of the nozzle, the flow regulating valve is used to adjust the spray flow rate of the nozzle, the inlet end of the pump is connected to the liquid medicine tank, and the outlet end of the pump is connected to the nozzle through the application connection pipeline.

[0033] The third object of the present invention is to provide a sprayer, which is characterized in that it includes a walking chassis and any one of the above-mentioned variable application regulation systems based on leaf density, and the variable application regulation system based on leaf density is installed on the walking chassis.

[0034] In this solution, the leaf area volume density (hereinafter referred to as "leaf density") mentioned refers to the sum of the canopy leaf areas per unit volume (m 2 / m 3 ), which can better characterize the growth characteristics of the canopy. Leaf density has a significant impact on both the droplet deposition inside the fruit tree canopy and the droplet drift behind the canopy. Therefore, using leaf density as a variable decision condition for target variable spraying is of great significance for improving the utilization rate of pesticides and achieving precise application.

[0035] Compared with the prior art, the present invention has at least the following beneficial effects:

[0036] First, the present invention provides a variable pesticide application regulation method based on the leaf density of fruit tree canopies. By constructing a leaf density - pesticide application amount regulation model, this solution can effectively provide a theoretical basis for precise pesticide application control, thereby improving the utilization rate of pesticides; and effectively reducing the risk of environmental pollution. This solution can achieve precise pesticide application. By real - time detecting the leaf density (leaf area per unit volume) of fruit tree canopies and combining multi - source data such as lidar and ultrasonic sensors, a dynamic regulation model of "leaf density - pesticide application amount" is constructed to achieve precise pesticide application on demand. Compared with the traditional extensive pesticide application method, the effective utilization rate of pesticides in the pesticide application regulation method of this solution has been significantly improved. It can not only reduce the waste caused by excessive pesticide application; but also reduce the risk of environmental pollution (variable regulation based on leaf density can avoid excessive deposition and droplet drift of pesticides, reduce soil, water source and air pollution, meeting the sustainable development needs of green agriculture).

[0037] Second, the present invention also discloses a variable pressure regulation system using the above - mentioned variable pressure regulation method, which mainly consists of a walking unit, a data acquisition unit, a central control unit, a target - oriented execution mechanism, a fan and a variable pesticide application unit, etc. The data acquisition unit obtains data related to the operation environment and relevant parameters of the variable pressure regulation system itself, and feeds the acquired data back to the central control unit. The central control unit controls the walking unit, the target - oriented execution mechanism, the fan and the variable pesticide application unit to execute corresponding control instructions according to the received relevant parameters, so as to realize the spraying operation in different working modes. This solution can use the leaf density as the key regulation parameter, combine multi - sensor fusion, dynamic delay compensation and closed - loop control technologies, break through the limitations of the traditional pesticide application system on the simplification of the canopy structure, and realize the precision, intelligence and environmental friendliness of orchard pesticide application. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0039] Figure 1 It is a schematic diagram of the overall structure of the sprayer of the present invention;

[0040] Figure 2 It is a schematic diagram of the target - oriented execution mechanism structure of the sprayer of the present invention;

[0041] Figure 3 It is a block diagram of the variable pesticide application regulation system of the present invention;

[0042] Figure 4 It is a flowchart of the operation of the variable pesticide application regulation system of the present invention;

[0043] Figure 5 This is the control flowchart of the variable application regulation system in the present invention;

[0044] Markings in the figure: 1. Chassis, 2. Pump, 3. LiDAR, 4. Electric control box, 5. Leaf density detection module, 6. Fan, 7. Target execution mechanism, 8. Flow solenoid valve, 9. Ultrasonic sensor, 10. Electric push rod, 11. Lifting mechanism, 12. Nozzle, 13. Fixed frame, 14. Air box housing, 15. Movable frame, 16. Air duct opening, 17. Liquid medicine tank, 18. Installation base frame. Specific embodiments

[0045] The present invention will be specifically described below through exemplary embodiments. However, it should be understood that without further description, the elements, structures, and features in one embodiment can also be beneficially combined with those in other embodiments.

[0046] It should be noted that: Unless otherwise defined, the technical terms or scientific terms used herein should have the ordinary meaning understood by those of ordinary skill in the art to which the present invention pertains. The words such as "a", "one", or "the" used in the specification and claims of this patent application for the invention do not express a limitation of quantity, but rather indicate the existence of at least one. Words such as "comprising" or "including" and the like indicate that the elements or objects appearing before "comprising" or "including" cover the elements or objects listed after "comprising" or "including" and their equivalents, but do not exclude other elements or objects having the same function.

[0047] As shown in the figure, this embodiment provides a variable application regulation method based on the leaf density of fruit tree canopies, including the following steps:

[0048] Step 1: Move the sprayer to the operation area and start the operation, collect relevant parameters during the operation of the sprayer, and send the collected relevant parameters to the central control unit.

[0049] Specifically, move the sprayer to the orchard operation area and start the system for operation. The variable application regulation system of the sprayer includes a walking unit and a data collection unit. The walking unit includes a speed sensor for measuring the moving speed of the sprayer; the data collection unit includes a LiDAR 3, a leaf density detection module 5, and an ultrasonic sensor 9. The LiDAR 3 is used to measure the width of the target fruit tree canopy as the system operation moving distance L v , the leaf density detection module 5 is used to measure the leaf density ρ of the target fruit tree canopy favd , and the ultrasonic sensor 9 is used to measure the distance L between the nozzle 12 and the target fruit tree canopy d, the pressure sensor of the variable dosing unit measures the spray pressure P of the nozzle. The collected data is uploaded to the host computer of the central control unit in real time for calculating the variable dosing control signal.

[0050] Step 2: The central control unit calculates the required amount of medicine per unit volume of the fruit tree canopy in the operation area according to the relevant parameters collected in Step 1, compensates the amount of medicine, fits the relationship between the flow rate of the dosing nozzle and the PWM duty cycle signal, and constructs a variable dosing control model based on the PWM duty cycle signal regulation.

[0051] In this Step 2, a method for constructing a variable dosing control model based on leaf density is designed. The lower computer of the central control unit adjusts the flow solenoid valve 8 according to the PWM duty cycle signal to achieve the adjustment of the nozzle flow rate. First, a relationship model between the nozzle flow rate and the leaf density is constructed, and then a calibration test is carried out to analyze the nozzle flow rate under different PWM duty cycle signals, obtain the functional relationship between the nozzle flow rate and the duty cycle signal, and further obtain the dosing control model based on the duty cycle signal.

[0052] The standard for low-dose spraying of fruit trees is that the number of droplets per square meter on the leaves is not less than n drops. Based on this, a variable dosing control model for leaf density is established according to the following steps:

[0053] Calculation of the effective spraying demand per unit volume of the fruit tree canopy. Assume the leaf density is ρ favd , for fruit tree spraying, both the front and back sides of the leaves need to be sprayed, so the leaf area per unit volume is 2ρ favd , simplifying the droplets into spherical shapes, the required amount of liquid medicine per unit volume of the fruit tree canopy is:

[0054]

[0055] In formula (5), Q1 is the required amount of liquid medicine per unit volume of the fruit tree canopy, D v is the droplet diameter;

[0056] The droplet diameter D v has the following relationship with the spray pressure of the nozzle:

[0057]

[0058] In formula (6), C v is a constant, C v specifically a constant related to the nozzle, related to the surface tension coefficient of the liquid, air density, etc., and P is the spray pressure;

[0059] During the process of droplets reaching the fruit tree canopy from the nozzle, some droplets will volatilize or be lost, so the amount of liquid medicine sprayed by the nozzle 12 satisfies formula (7);

[0060] Q = k·Q1 + Q2 (7)

[0061] In Equation (7), Q is the amount of liquid medicine sprayed by the nozzle, Q2 is the amount of liquid medicine lost, k is the correction coefficient, and k = 2 is taken in this solution;

[0062] Ignoring the influence of environmental factors, Q2 and the distance L between the nozzle and the fruit tree canopy d Satisfy:

[0063] Q2 = δL d ·Q (8)

[0064] In Equation (8), δ is a constant greater than 0, and δ = 0.1 is taken in this solution;

[0065] The relationship between the amount of liquid medicine Q sprayed by the nozzle and the nozzle flow rate q satisfies Equation (9):

[0066] Q = q·t

[0067]

[0068] In Equation (9), t is the time required for the nozzle to spray the liquid medicine amount Q, which is related to the traveling speed v of the sprayer, and L v Is the moving distance of the system operation within time t;

[0069] Therefore, the spray flow rate of the nozzle satisfies Equation (10):

[0070]

[0071] Under certain pressure and frequency range conditions, there is a linear relationship between the spray flow rate q of the nozzle and the PWM duty cycle x, that is:

[0072] q = ax + b (11)

[0073] In Equation (11), a and b are constants obtained when deriving the equation for fitting the straight line, and are obtained by fitting the calibration results of the chemical application amount based on the duty cycle.

[0074] According to Equation (10) and Equation (11), Equation (12) can be obtained:

[0075]

[0076] In Equation (12), x is the duty cycle, n is the constant specified by the low-dose chemical application standard for fruit trees, k is the correction coefficient, v is the traveling speed of the sprayer, ρfavd is the leaf density, Cv is a constant related to the nozzle, δ is a constant greater than 0, and L dis the distance between the nozzle and the fruit tree canopy, P is the spraying pressure, Lv is the driving distance of the sprayer within time t, and a and b are constants obtained when deriving the formula for the fitting straight line. a and b are obtained by fitting the calibration results of the chemical application rate based on the duty cycle.

[0077] In this solution, the following calibration test method is adopted to fit the relationship between the flow rate of the chemical application nozzle and the duty cycle signal, so as to establish a variable chemical application control model:

[0078] The steps of the calibration test method are as follows:

[0079] Step 21: Adjust the opening and closing angle of the flow control solenoid valve 8, set the opening and closing angle of the first group of tests, and collect the liquid output of the nozzle using a specific container.

[0080] Step 22: Open the flow control solenoid valve 8 and the pump 2, continuously collect the liquid output of the nozzle 12 under a specific spraying pressure and within a specific time. When the collection time arrives, close the flow control solenoid valve 8 and the pump 2.

[0081] Step 23: After a group of tests, adjust the flow control solenoid valve 8 to the next opening and closing angle, repeat the above process of collecting the liquid output of the nozzle 12. The opening and closing angle of the flow control solenoid valve 8 increases step by step with a first specific amount, and count the liquid output of the nozzle 12 at a specific opening and closing angle.

[0082] Step 24: According to the liquid output of the nozzle at each specific opening and closing angle of the flow control solenoid valve 8 counted in Step 23, select a specific opening and closing angle range of the flow control solenoid valve 8, and conduct supplementary tests within the range of the specific opening and closing angle of the flow control solenoid valve 8. The supplementary test method is: open the flow control solenoid valve 8 and the pump 2, continuously collect the liquid output of the nozzle 12 under a specific spraying pressure and within a specific time. When the collection time arrives, close the flow control solenoid valve 8 and the pump 2. After a group of tests, adjust to the next opening and closing angle, repeat the above process of collecting the liquid output of the nozzle 12. The opening and closing angle of the flow control solenoid valve 8 increases with a second specific amount, and count the liquid output of the nozzle 12 at this opening and closing angle. The value of the second specific amount is less than the first specific amount.

[0083] Specifically, the purpose of calibrating the chemical application rate based on PWM is to obtain the corresponding relationship between the opening and closing angle of the flow solenoid valve 8 and the nozzle flow rate. The main test equipment includes a weighing device, a timer, a variable spraying unit, etc. The weighing device is used to weigh the container during the test, and the liquid medium used for measurement is water. The timer is used to calculate the collection time of the water output during the test. The opening and closing angle of the flow solenoid valve 8 is controlled by the lower computer of the central control unit sending a PWM duty cycle signal. The duty cycle signals of 0-100% respectively correspond to the opening and closing angles of 0-100% of the flow solenoid valve 8. Among them, the opening and closing angle of 0% of the flow solenoid valve 8 means that the flow solenoid valve 8 is completely closed, and the opening and closing angle of 100% of the flow solenoid valve 8 means that the flow solenoid valve 8 is completely open. The test method is as follows: Adjust the opening and closing angle of the flow solenoid valve 8. In the first group of tests, set the opening and closing angle of the flow solenoid valve 8 to 5%. Use a water-containing container to collect the water output of the nozzle (weigh the weight of the empty container itself before the test starts). Open the flow solenoid valve 8 and the pump 2, where the spraying pressure is P. After continuously collecting the water output for 60 s, close the flow solenoid valve 8 and the pump 2. Use the weighing device to weigh the total weight of the container at this time and calculate the net water output (the total weight of the water-containing container minus the weight of the container itself). Repeat the above process 3 times at each opening and closing angle of the flow solenoid valve 8, and take the average value of the 3 times. After a group of tests, adjust the opening and closing angle and repeat the above process. The opening and closing angle first increases by 5% to observe the overall change law of the spraying flow rate. According to the overall change law, select a suitable opening and closing angle interval of the flow solenoid valve 8, and then conduct supplementary tests. In the supplementary tests, the opening and closing angle of the flow solenoid valve 8 increases by 2% for a total of 30 groups.

[0084] Based on the above test result data, a corresponding relationship model between the duty cycle and the nozzle spraying flow rate is established by using the single-factor linear fitting method:

[0085] The spraying flow rate first increases rapidly (the first stage), then increases steadily (the second stage), and finally tends to be stable (the third stage) as the duty cycle signal (the opening and closing angle of the flow solenoid valve 8) increases. Since the spraying flow rate increases too fast in the first stage and the control difficulty is relatively large, and the adjustment of the duty cycle has little effect on the spraying flow rate in the third stage, for the convenience of constructing the subsequent chemical application rate control model, this solution takes the second stage for fitting construction, that is, the stage from x1 to x2 of the duty cycle, and fits this stage. The values of a and b in the function relationship formula (11) between the spraying flow rate q and the duty cycle x can be calculated, and the relationship between the leaf density and the duty cycle x satisfies formula (12). Therefore, combined with the actual chemical application requirements and the characteristics of the target variable spraying, the variable chemical application control model based on the PWM duty cycle x is shown in formula (13):

[0086]

[0087] In Equation (13), x1 is the minimum duty cycle required for the flow solenoid valve to open, and x2 is the minimum duty cycle for the flow solenoid valve to be fully open.

[0088] Step 3: Calculate the PWM duty cycle signal based on the operating parameters of the control system obtained in Step 1, the target fruit tree canopy leaf density, and the variable spraying control model in Step 2. The central control unit regulates the flow solenoid valve 8 according to this signal, thereby realizing variable spraying control.

[0089] In this Step 3, by combining the real-time feedback of the flow meter with the PWM duty cycle adjustment, a closed-loop control is formed to dynamically calibrate the opening degree of the flow solenoid valve 8, making the actual flow rate consistent with the target flow rate, and enhancing the anti-interference ability and long-term operating stability of the system.

[0090] The control method of this solution constructs a relationship model between the nozzle flow rate and the leaf density by designing a construction method for a variable spraying control model based on leaf density. Then, a calibration test is carried out to analyze the flow rate of the nozzle 12 under different duty cycle signals, obtain the functional relationship between the flow rate of the nozzle 12 and the duty cycle signal, and further obtain a spraying amount control model based on the duty cycle signal. The flow control valve is adjusted according to the duty cycle, and then the adjustment of the nozzle flow rate is realized.

[0091] In this solution, it is considered that the control variable system can further compensate for the delay of the spraying calculation time of the nozzle. The reason is that the lidar 3 and the leaf density detection module 5 are installed in front of the walking chassis 1, while the nozzle 12 is installed behind the walking chassis 1, and there is a position delay between the detection end and the response end;

[0092] Assume that the time required from detecting the target to the nozzle to start spraying is T0, the traveling speed of the sprayer is V0, and the horizontal distance between the detection system and the nozzle is L0, which satisfies Equation (14).

[0093]

[0094] It can be seen from Equation (14) that the greater the traveling speed of the sprayer, the shorter the delay time.

[0095] However, considering the speed of the electric push rod 10 to adjust the spray elevation angle, the traveling speed of the sprayer cannot be too large. The delay time has a minimum value T 0min , and the corresponding walking chassis 1 has a maximum traveling speed V 0max . Assume that the maximum adjustment speed of the electric push rod 10 is v max , the maximum spray elevation angle is α max The corresponding stroke of the electric push rod is l max , the minimum spray elevation angle is α min The corresponding stroke of the electric push rod is l min , and the spray elevation angle adjustment limit is that the spray elevation angle ranges from α minAdjust to α max , the minimum delay time T 0min should be greater than or equal to the time required for the spray elevation angle adjustment limit to ensure that the spray elevation angle adjustment requirements are met. The calculation formula is:

[0096]

[0097] In addition, considering that the flow solenoid valve 8 and the nozzle 12 are installed at different positions, there must be a certain distance between the nozzle 12 and the flow solenoid valve 8, and there will also be a certain time lag between the opening and closing of the flow solenoid valve 8 and the opening and closing of the nozzle 12. Therefore, the control system needs to compensate for this part of the delay time.

[0098] Assume that the velocity of the liquid medicine in the pipeline is v0, assume that the distance between the pipeline between the nozzle and the flow solenoid valve 8 is L1, and ignore the influence of the pipeline bending on the velocity. Then the time T1 required for the liquid medicine to flow from the flow solenoid valve 8 to the nozzle satisfies formula (16).

[0099]

[0100] To sum up, the compensation of the delay time by the control system is as shown in formula (17), and it is necessary to compare the magnitudes of T1 and T 0min , and the compensation time Tˊ is set to the larger value between the two.

[0101]

[0102] After calculating the compensation time T’, the time compensation is carried out by adjusting the traveling speed of the sprayer. T’ is the minimum value of T0 in formula (10), L0 is a fixed value, and the time compensation is carried out by adjusting V0 to ensure that T0 is greater than or equal to T’.

[0103] As Figure 4 shown, the control process of the sprayer includes at least the following three modes: remote control operation mode, semi-automatic operation mode, and automatic operation mode; the following is an introduction to the three modes respectively:

[0104] The control process of the remote control operation mode is as follows:

[0105] After the control unit is powered on and initialized, when the remote-controlled sprayer reaches the spraying area, it first determines whether the sprayer has reached the predetermined area to be sprayed. If it has reached the predetermined area to be sprayed, it further adjusts the height of the lifting mechanism 11 (raising or lowering the height of the nozzle 12 through the lifting mechanism 11) and the angle of the target-facing actuator 7 (adjusting the spraying angle of the nozzle 12 through the angle of the target-facing actuator 7), and determines whether the nozzle 12 is facing the spraying area. If it is facing the spraying area, the flow solenoid valve is opened; if the nozzle 12 is not facing the area to be sprayed, the angle of the nozzle 12 of the target-facing actuator 7 is continuously adjusted until the nozzle 12 is facing the spraying area.

[0106] Then, the fan 6 and the pump 2 are started. The sprayer remotely advances along the rows of fruit trees and starts continuous spraying until the spraying is completed. If the spraying operation is not completed, the sprayer can remotely continue to advance along the rows of fruit trees and continuously spray; subsequently, components such as the pump 2, the fan 6, and the flow solenoid valve 8 are closed, and the target-facing actuator 7 is reset, then the spraying operation ends.

[0107] The control process of the semi-automatic operation mode is as follows:

[0108] After the control unit is powered on and initialized, when the remote-controlled sprayer reaches the area to be sprayed, it first determines whether the sprayer has reached the predetermined area to be sprayed. If it has reached the predetermined area to be sprayed, it further adjusts the height of the lifting mechanism 11, then resets the target-facing actuator 7, starts the fan 6 and the pump 2, and controls the sprayer to travel along the rows of fruit trees by remote control. The variable application control of the sprayer automatically determines whether there is a target. If a corresponding target is found, the electric push rod 10 adjusts the spraying angle of the nozzle 12, and the flow solenoid valve 8 is opened. Then, the variable spraying is automatically controlled through the variable application control system, and it is determined whether the spraying is completed. If the spraying is not completed, the sprayer continues to travel along the rows of fruit trees in the remote control mode. If the spraying has been completed, the pump 2, the fan 6, and the flow solenoid valve 8 are closed, and the target-facing actuator 7 is reset, then the spraying operation ends.

[0109] The control process of the automatic operation mode is as follows:

[0110] After the control unit is powered on and initialized, when the remote-controlled sprayer reaches the area to be sprayed, it first determines whether the sprayer has reached the predetermined area to be sprayed. If it has reached the predetermined area to be sprayed, the height of the lifting mechanism 11 is further adjusted. Then, the target execution mechanism 7 is reset, the fan 6 and the pump 2 are started, and the automatic navigation between rows is enabled. The sprayer advances automatically along the rows. The variable application control of the sprayer automatically determines whether there is a target. If the corresponding target is found, the electric push rod 10 adjusts the angle of the nozzle, and the flow solenoid valve 8 is opened. Then, the variable application control system starts to automatically control the variable spraying, and determines whether the spraying is completed. If the spraying is not completed, the sprayer continues to travel along the fruit tree rows in the remote control mode. If the spraying has been completed, the pump 2, the fan 6 and the flow solenoid valve 8 are closed, and the target execution mechanism 7 is reset, then the spraying operation ends.

[0111] As described above, the semi-automatic operation mode is to remotely control the movement of the sprayer, and the automatic operation mode is to automatically navigate between rows. The automatic operation mode is suitable for orchards with regular planting or less obvious canopy closure between rows. When encountering the situation of canopy closure between rows, it can be randomly switched to the semi-automatic mode to remotely adjust the driving track between rows to ensure the uniform application of pesticides on both sides of the fruit trees. The control of the target is realized by the central control unit driving the lifting mechanism 11 and the electric push rod 10 according to the position information of the target fruit tree canopy collected by the lidar 6, and adjusting the nozzle 12 to the optimal height and angle for spraying operation. The control of variable application is realized by the slave computer of the central control unit driving the flow solenoid valve 8 according to the calculated PWM duty cycle signal, and adjusting the spraying flow by adjusting the opening and closing angle of the flow solenoid valve 8. At the same time, the flow meter real-time detects the actual flow, and the central control unit finely adjusts the opening and closing angle of the flow solenoid valve 8 by calculating the difference between the actual flow and the target flow to ensure that the actual flow is consistent with the target flow, so as to realize the variable application control.

[0112] The above multi-mode flexibly adapts to complex scenarios and supports three operation modes: remote control, semi-automatic, and automatic, adapting to different orchard environments (such as the degree of canopy closure between rows and the degree of planting standardization). The automatic navigation mode is suitable for standardized orchards, and the semi-automatic mode can cope with complex terrains through manual intervention, which can effectively improve the adaptability of the system.

[0113] This solution also provides a variable application control system based on leaf density, including a traveling unit, a data acquisition unit, a central control unit, a target execution mechanism, a fan, and a variable application unit;

[0114] The data acquisition unit is signal-connected to the central control unit. The data acquisition unit includes a lidar 3, a leaf density detection module 5, and an ultrasonic sensor 9. The lidar 6 is used to detect the width and position information of the fruit tree canopy; the leaf density detection module 5 is used to measure the leaf density information of the target fruit tree canopy, and the ultrasonic sensor 9 is used to measure the distance from the pesticide spraying nozzle to the target fruit tree canopy; the lidar 3, the leaf density detection module 5, and the pump 2 are arranged at the front end of the sprayer. The ultrasonic sensor 9 is arranged on the target spraying actuator 7 and is used to measure the distance between the nozzle 12 and the target fruit tree canopy. The system components of this solution (such as lidar, leaf density detection module, electric control box, etc.) adopt a modular layout, with standardized interfaces reserved, which is convenient for installation, debugging, later upgrade and maintenance, and reduces the use cost.

[0115] In this solution, the central control unit is respectively signal-connected to the target spraying actuator 7 and the variable pesticide application unit, and is used to receive the data information of the data acquisition unit, calculate the pesticide application amount according to the collected data information, and send control instructions to the target spraying actuator 7 and the variable pesticide application unit according to the pesticide application amount; the central control unit includes a host computer and a slave computer, the host computer and the slave computer are signal-connected, and both the host computer and the slave computer are encapsulated inside the electric control box 4 and are arranged above the front end of the walking chassis 1 of the sprayer. The host computer and the slave computer reserve a power supply interface and a data transmission interface. The slave computer is respectively signal-connected to the drive motor, the lifting mechanism (lifting motor) 11, the electric push rod 10, the fan 6, the flow solenoid valve 8, and the flow meter to obtain the spray flow information and send corresponding execution instructions. The host computer is used to obtain the corresponding data information, calculate the required pesticide application amount, and at the same time send corresponding signal instructions to the slave computer.

[0116] In this solution, the variable dosing unit is used to control the dosing flow rate of the nozzle 12 through the flow solenoid valve 8. The variable dosing unit includes a pump 2, a flow solenoid valve 8, a pressure sensor, and a flow meter; the pump 2, the flow solenoid valve 8, the pressure sensor, and the flow meter are arranged on the dosing connection pipeline. The pressure sensor is used to measure the spraying pressure of the nozzle 12, the flow meter is used to obtain the flow rate of the nozzle 12, the flow solenoid valve 8 is used to adjust the flow rate of the nozzle 12, the inlet end of the pump 2 is connected to the liquid medicine tank 17, and the outlet end of the pump 2 is connected to the nozzle 12 through the dosing connection pipeline. The pressure sensor, the flow meter, and the flow solenoid valve 8 are arranged on the dosing connection pipeline between the pump 2 and the nozzle 12. The pressure sensor, the flow meter, the flow solenoid valve 8, and the fan 6 are mounted on the target-facing actuator 7 and arranged at the rear end of the sprayer. Specifically, the fan 6 is arranged on the air box housing 14 and sends external air flow into the internal air cavity of the air box housing 14 and sends it out through its air duct opening 16. The target-facing actuator 7 is used to control the height and spraying angle of the nozzle 12; the target-facing actuator 7 includes a lifting mechanism 11, an electric push rod 10, and an air box housing 14. The lifting mechanism 11 is used to adjust the height of the nozzle 12. The lifting mechanism 11 adopts a telescopic lifting motor. The upper end of the lifting mechanism 11 is provided with a horizontally arranged mounting base frame 18. The flow solenoid valve 8 can be fixedly arranged on the mounting base frame 18. The inlet and outlet of the flow solenoid valve 8 are respectively connected to the dosing pipeline. The two ends of the mounting base frame 18 are rotatably provided with movable frames 15. The lower end of the lifting mechanism 11 is fixedly connected to the fixed frame 13. The electric push rod 10 is used to adjust the spraying angle of the nozzle 12. One end of the electric push rod 10 is hinged to the mounting base frame 18, and the other end of the electric push rod 10 is hinged to the movable frame 15. In this solution, the angle adjustment of the movable frame 15 can be realized by the telescopic movement of the electric push rod 10. Thus, the function of adjusting the spraying angle of the nozzle 12 is achieved.The housing of the bellows housing 14 is fixed to the upper end of the lifting mechanism 11. The nozzle 12 and its related installation and adjustment accessories, the bellows housing 14, and the blower 6 can be synchronously height-adjusted along with the lifting action of the lifting mechanism 11. A wind cavity is formed inside the bellows housing 14. The wind cavity has air outlets 16 symmetrically arranged in two opposite directions. The mounting base frame 18, the electric push rod 10, and the movable frame 15 are located inside the bellows housing 14, and the movable frame 15 is located at the air outlets 16 on both sides. The nozzle 12 and the ultrasonic sensor 9 are fixedly installed on the movable frame 15, so that the nozzles 12 arranged at both ends of the movable frame 15 are located at the air outlets 16. The electric push rod 10 is used to drive the movable frame 15 to rotate a specific angle to achieve the angle adjustment of the nozzle 12. As shown in the figure, preferably, the ultrasonic sensor 9 is located at the middle position of the movable frame 15, and the nozzles 12 are symmetrically distributed at both ends of the movable frame 15. The blower 6 is fixed on one side of the tail end of the bellows housing 14 and is used to drive the external air flow into the wind cavity of the bellows housing 14, and the air flow will be discharged through the air outlets 16 on both sides of the bellows housing 14. In this solution, the blower 6 is used to blow the fruit tree leaves to flip through the air outlets 16 and carry the droplets sprayed by the nozzle 12 to the fruit tree canopy layer (the air flow drives the nozzle droplets to the fruit tree canopy layer position), improving the uniformity of droplet coverage on the front and back sides of the leaves. By driving the leaves to flip with the blower 6, the droplet penetration is enhanced, ensuring uniform coverage of the liquid medicine on the front and back sides of the leaves and improving the pest control effect.

[0117] This solution also provides a sprayer, which includes the above variable application rate regulation system and the traveling chassis 1. The traveling chassis 1 includes a chassis, track wheels located on both sides of the chassis, a driving motor (traveling motor), and a fixed frame 13 arranged above the chassis. The driving motor can drive the traveling chassis 1 to move between fruit tree rows. Each component of the variable application rate regulation system is distributed on the fixed frame 13. Preferably, the lidar 3, the leaf density detection module 5, and the pump 2 are installed at the front end position on the fixed frame 13; the target execution mechanism 7 is arranged at the tail end position of the fixed frame 13, and the liquid medicine tank 17 and the pump 2 are both installed inside the frame of the fixed frame 13 to fully realize the rational utilization of space.

[0118] The above are only the preferred embodiments of the present invention and do not impose any form of limitation on the present invention. Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to the above-disclosed technical content to make equivalent embodiments with equivalent changes within the scope of the technical solution of the present invention. However, as long as it does not depart from the content of the technical solution of the present invention, any simple modification, equivalent change, and modification made to the above embodiments according to the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A variable rate spraying control method based on leaf density, characterized in that: The steps include: Step 1: Collect relevant parameters during the operation of the sprayer, and send the collected relevant parameters to the central control unit; Step 2: Calculate the required pesticide application amount per unit volume of the fruit tree canopy in the operation area based on the relevant parameters collected in step 1, fit the relationship between the spray nozzle flow rate and the duty cycle signal, and construct a variable spraying control model based on duty cycle signal regulation; Step 3: Calculate the duty cycle signal based on the sprayer operating parameters obtained in step 1 and the variable pesticide application control model in step 2, and the central control unit controls the flow solenoid valve (8) based on the duty cycle signal, thereby realizing variable pesticide application control.

2. The variable rate pesticide application control method based on leaf density according to claim 1, characterized in that: In the step 1, the sprayer is moved to the operating area, the sprayer is started to operate, the moving speed of the sprayer, the width and position information of the target fruit tree canopy, the target fruit tree leaf density, the distance between the nozzle and the target fruit tree canopy and the nozzle spray pressure are measured, and the collected data is uploaded to the central control unit in real time.

3. The variable rate pesticide application control method based on leaf density according to claim 1, characterized in that: In the step 2, the relevant parameters collected in the step 1 are used to calculate the required amount of pesticide to be applied per unit volume of the canopy of the fruit trees in the operation area, which is calculated by the following formula (1): Where Q1 is the amount of liquid required per unit volume of the fruit tree canopy, n is a constant specified in the standard for low-volume pesticide application for fruit trees, representing the number of droplets per square meter, and ρ favd is the leaf density, C v is a constant related to the nozzle, and P is the spray pressure.

4. The variable rate pesticide application control method based on leaf density according to claim 1, characterized in that: In the step 2, the required amount of pesticide application per unit volume of the canopy of the fruit trees in the operation area is calculated according to the relevant parameters collected in the step 1, and the amount of pesticide application is compensated, the relationship between the flow rate of the pesticide spray nozzle and the duty cycle signal is fitted, and a variable pesticide application control model based on duty cycle signal regulation is constructed; The amount of liquid medicine required to compensate for the amount of medicine applied is calculated by the following formula (2): In the formula, Q is the amount of liquid sprayed by the nozzle, k is the correction coefficient, δ is a constant greater than 0, and L d is the distance between the nozzle and the canopy of the fruit tree, q is the spray flow rate of the nozzle, L v is the distance traveled by the sprayer in time t, and v is the speed of the sprayer.

5. The variable rate pesticide application control method based on leaf density according to claim 1, characterized in that: In the step 2, the relationship between the fitting spray nozzle flow rate and the duty cycle signal is that under certain pressure and frequency range conditions, the nozzle spray flow rate q and the duty cycle x satisfy the linear relationship of formula (3), that is: q=ax+b(3) Wherein, a and b are constants obtained when deriving the formula for fitting the straight line, and are obtained by fitting the calibration results of the dosage based on the duty cycle.

6. The variable rate pesticide application control method based on leaf density according to claim 5, characterized in that: The variable pesticide application control model based on duty cycle signal regulation is constructed by calculating the relationship between the fruit tree leaf density and the variable pesticide application control signal, which is calculated by the following formula (4): In the formula, x is the duty cycle, n is the constant specified in the standard for low-volume spraying of fruit trees, k is the correction coefficient, v is the speed of the sprayer, and ρ favd is the leaf density, C v is a constant related to the nozzle, δ is a constant greater than 0, L d is the distance between the nozzle and the canopy of the fruit tree, P is the spray pressure, L v is the travel distance of the sprayer within time t, a and b are the constants obtained when deriving the formula for fitting the straight line, and a and b are fitted based on the calibration result of the duty cycle.

7. The variable rate pesticide application control method based on leaf density according to claim 5, characterized in that: In the step 2, the following experimental method is used to fit the relationship between the spray nozzle flow rate and the duty cycle signal to establish a variable spraying control model: Step 21, adjusting the opening and closing angle of the flow electromagnetic valve (8), setting a first set of test opening and closing angles, and using a specific container to collect the liquid output of the nozzle; Step 22, opening the flow electromagnetic valve (8) and the pump (2), continuously collecting the water output of the nozzle (12) under a specific spray pressure and within a specific time, and closing the flow electromagnetic valve (8) and the pump (2) when the collection time is up; Step 23, after a set of tests are completed, the flow electromagnetic valve (8) is adjusted to the next opening and closing angle, and the above process of collecting the water output of the nozzle (12) is repeated, the opening and closing angle of the flow electromagnetic valve (8) is increased step by step by a first specific amount, and the liquid output of the nozzle (12) at the specific opening and closing angle is counted; Step 24, based on the nozzle liquid output at each specific opening and closing angle of the flow solenoid valve (8) counted in step 23, select a specific opening and closing angle interval of the flow solenoid valve (8), and perform a supplementary test within the specific opening and closing angle interval of the flow solenoid valve (8), the supplementary test method is: open the flow solenoid valve (8) and the pump (2), continuously collect the liquid output of the nozzle (12) under a specific spray pressure and within a specific time, and when the collection time is up, close the flow solenoid valve (8) and the pump (2); after a set of tests, adjust to the next opening and closing angle, repeat the above-mentioned nozzle (12) liquid output collection process, the opening and closing angle of the flow solenoid valve (8) is increased by a second specific amount, and the nozzle (12) liquid output at the opening and closing angle is counted; the second specific amount value is less than the first specific amount value.

8. A variable rate pesticide application control system based on leaf density, characterized in that: It includes data acquisition unit, central control unit, target actuator and variable dosage unit. The data acquisition unit is connected to the central control unit by signal, and the data acquisition unit comprises a laser radar (3), a leaf density detection module (5), and an ultrasonic sensor (9). The laser radar (3) is used to detect the width and position information of the canopy of the target fruit tree; the leaf density detection module (5) is used to measure the leaf density information of the canopy of the target fruit tree; and the ultrasonic sensor (9) is used to measure the distance from the nozzle (12) to the canopy of the target fruit tree; The central control unit is respectively connected to the target actuator (7) and the variable dosage unit signal, and is used to receive data information from the data acquisition unit, calculate the dosage amount according to the acquired data information, and send control instructions to the target actuator (7) and the variable dosage unit according to the dosage amount; The target actuator (7) is used to control and adjust the height and spray angle of the nozzle (12); The variable-variable spraying unit is used to control the spray flow rate of the spray head (12).

9. The variable rate pesticide application control system based on leaf density according to claim 8, characterized in that: The variable spraying unit comprises a pump (2), a flow electromagnetic valve (8), a pressure sensor and a flow meter; the pump (2), the flow regulating valve (8), the pressure sensor and the flow meter are arranged on a spraying connection pipeline, the pressure sensor is used to measure the spray pressure of the nozzle (12), the flow meter is used to obtain the spray flow of the nozzle (12), the flow regulating valve (8) is used to adjust the spray flow of the nozzle (12), the inlet end of the pump (2) is connected to the liquid medicine tank (15), and the outlet end of the pump (2) is connected to the nozzle (12) through the spraying connection pipeline.

10. A spray machine, characterized in that: It comprises a walking chassis (1) and a variable-rate pesticide application control system based on leaf density as claimed in claim 8 or 9, wherein the variable-rate pressure control system based on leaf density is installed on the walking chassis (1).

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