Variable irrigation control method for large sprinkler

Abstract

The invention discloses a variable irrigation control method for a large sprinkler, which comprises the following steps of: installing a variable irrigation controller on each sprinkler head of the sprinkler to adjust the irrigation amount of the sprinkler head, forming a network by adopting wireless communication among the variable irrigation controllers, and adjusting the irrigation amount of the sprinkler head through a valve opening degree adjusting algorithm built in the variable irrigation controller. The opening degree of the valve is adjusted in real time, and the water yield of the spray head is rapidly stabilized on the target water yield required by an irrigation prescription map. The variable irrigation controller is used for controlling the valves to adjust the flow of each nozzle of the sprinkler, meanwhile, a cooperative control network is formed among the valves, the opening degree of each valve is calculated through an artificial intelligence algorithm, and therefore variable irrigation of the sprinkler with the valves independently adjusted is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of agricultural irrigation, and particularly to a variable irrigation control method for a large-scale sprinkler irrigation machine. Background Art

[0002] Irrigation is the most important link in agricultural production. As a modern irrigation technology carrier with a relatively high degree of intensification of modern agricultural water-saving and efficient irrigation technology equipment, the large-scale sprinkler irrigation machine will play a major role in the development of intensive and large-scale agricultural production and the construction of ecological farmland in China due to its advantages of good irrigation quality and effect, wide application range, and high degree of automation.

[0003] There are two common structures for large-scale sprinkler irrigation machines: the pointer-type large-scale sprinkler irrigation machine and the moving-type large-scale sprinkler irrigation machine. The large pointer-type sprinkler irrigation machine is also called the center pivot sprinkler irrigation machine. It is provided with sprinkler heads on a bracket that can automatically move. During operation, the machine rotates around the center point equipped with a water supply system while sprinkling irrigation. Because its walking mode is like the pointer of a clock, it is called the pointer-type sprinkler irrigation machine, also known as the center pivot sprinkler irrigation machine or the circular sprinkler irrigation machine. The height of the truss from the ground is usually 2 - 3m, and the span of the truss is usually 30 - 65m. A sprinkler irrigation machine can consist of more than 10 spans at most. The large moving-type sprinkler irrigation machine is composed of a lateral pipe, sprinkler heads, traveling wheels, and a truss, and is a sprinkler irrigation system that moves along the direction perpendicular to the lateral pipe. Its lateral pipe is the same as that of the clockwise sprinkler irrigation system and is also supported on a truss that can automatically move. However, the truss moves in a straight line and sprinkles irrigation while moving. This sprinkler irrigation system is supplied with water by an open channel perpendicular to the lateral pipe, or can also be supplied with water by a water hydrant on the main pipe through a hose. The sprinkler irrigation area is rectangular. The structures of the truss and the tower truck are similar to those of the pointer-type sprinkler irrigation machine, and the longest moving length of the moving-type sprinkler irrigation machine can reach 1000 meters.

[0004] However, due to the long truss of the sprinkler and factors such as undulating terrain, the sprinkler irrigation is uneven, resulting in problems such as the decline in crop quality and the waste of water resources, which affects the full play of the sprinkler in improving agricultural production efficiency. Researchers have tried to adopt automatic control technology to control the spraying amount in different areas of the sprinkler according to the growth of crops and the undulation of the terrain, so as to improve the uniformity of sprinkler irrigation. Variable rate irrigation (VRI) technology originated in the early 21st century and has become an important research direction for large sprinkler irrigation machines. So far, the application research of foreign variable rate irrigation technology in precision irrigation has made great progress to a large extent. The control strategies based on realizing variable rate irrigation (VRI) can be divided into three types: SPEED-VRI, ZONE-VRI, and IS-VRI. The early VRI technology mainly achieved variable control of different areas by controlling the walking speed of the sprinkler. Although this method realized the adjustment of irrigation amount in the traveling direction, due to the large span of the sprinkler, the irrigation amount in the sprinkler direction was the same, which limited the further adjustment of irrigation uniformity. Subsequently, the emerging ZONE-VRI technology divided the nozzles on the sprinkler into several groups, and the flow rate of each group was adjusted uniformly, successfully solving the problem of uneven irrigation in the sprinkler direction. The fineness of this method depends on the grouping, and variable control cannot be achieved within the group. At present, the IS-VRI (Individual Sprinkler VRI) method with more flexible control and higher irrigation uniformity has gradually become the main direction of variable control of sprinklers. This method takes individual nozzles as the object of variable control, and the flow rate of each nozzle can be adjusted. The plot can be divided into smaller management units to maximize the irrigation uniformity. Chinese Patent - Method, System, Medium and Equipment for Obtaining the Water Depth Below the Working Area of a Large Variable Rate Sprinkler (Publication No. CN116384195A) gives a method for calculating the required prescription for each area in the sprinkler irrigation area, which can calculate the water volume required at different positions in the sprinkler irrigation area according to factors such as terrain. The calculation results are as Figure 1 ; Chinese Patent - Large PWM Variable Rate Sprinkler Valve Front Signal Integration System and Equipment (Publication No. CN116649189A) gives a method for adjusting the flow rate of nozzles based on PWM control, such as Figure 2 , to achieve the flow rate adjustment of the nozzles. At the same time, Chinese Patent - Single Valve Pulse Width Modulation Controller for Large Variable Rate Sprinklers (Publication No. CN110161912A) gives the design method of this controller.

[0005] The existing methods do not consider that when the nozzles on the sprinkler pipeline are opened simultaneously, the actual flow rate between the nozzles will be affected due to the limitation of the water pump pressure. In the existing patents, the method of using the PWM method to control the flow rate of each nozzle of the sprinkler is to control the flow rate of each nozzle by controlling the opening time of the nozzle. It is very difficult to predict and control the situation where the nozzles are opened simultaneously. When considering the pressure change caused by the change of the pipeline flow rate after the nozzle is opened, the control accuracy will decrease significantly, and it is very difficult to achieve the expected control result in actual applications.

[0006] Therefore, how to provide a variable irrigation method suitable for large-scale translational sprinklers has become a technical problem that needs to be solved urgently by those skilled in the art. Summary of the Invention

[0007] In view of this, the purpose of the present invention is to provide a variable irrigation control method for large-scale sprinklers, which uses a variable irrigation controller to control the valves to adjust the flow rate of each nozzle of the sprinkler. At the same time, a cooperative control network is formed between each valve, and an artificial intelligence algorithm is used to calculate the opening degree of each valve, so as to realize the variable irrigation of the sprinkler with independent valve adjustment.

[0008] The present invention adopts the following technical solutions to solve the technical problems:

[0009] A variable irrigation control method for a large-scale sprinkler, including: adjusting the irrigation water volume of the nozzle by installing a variable irrigation controller on each nozzle of the sprinkler, and using wireless communication to form a network between the variable irrigation controllers. Through the valve opening adjustment algorithm built in the variable irrigation controller, the real-time adjustment of the valve opening is realized, so that the water output of the nozzle can be quickly and stably set at the target water output required by the irrigation prescription map.

[0010] Further, the variable irrigation controller (1) is installed on each nozzle (3) branch pipe on the truss (2); the variable irrigation controller (1) realizes Internet access by accessing the irrigation gateway (4) installed on the main tower vehicle (5).

[0011] Further, the variable irrigation controller mainly consists of a ball valve for controlling the opening and closing of the sprinkler branch pipe, a ball valve control component with adjustable opening degree, a pressure sensor and a control circuit; among them, the ball valve for controlling the branch pipe switch is connected to the truss and the nozzle branch pipe, and opening the ball valve can deliver water to the nozzle; the opening and closing of the ball valve is controlled by the ball valve control component with adjustable opening degree; the pressure sensor is arranged in the nozzle branch pipe for real-time measurement of the water pressure in the nozzle branch pipe; the control circuit is respectively communicatively connected to the ball valve control component and the pressure sensor.

[0012] Furthermore, the ball valve control assembly is mainly composed of a motor, a reduction gear and a position sensor; wherein the output end of the motor is connected to the ball valve through the reduction gear, and the opening of the ball valve is adjusted by the rotation of the motor; the position sensor is used to feedback the opening of the ball valve.

[0013] Furthermore, the control circuit adopts ARM M4 series chips as the core MCU, embedded with a real-time operating system and a lightly simplified AI component.

[0014] Furthermore, a valve opening calculation model is provided on each core MCU, and the input of the valve opening calculation model is the target flow of other nozzles and the target flow of the valve, and the opening of the valve is output through the calculation of the model.

[0015] Furthermore, in the valve opening calculation model, the forget gate controls information removal, the input gate controls the addition of new information, and the output gate determines the next state output.

[0016] Furthermore, the irrigation gateway is a gateway device with two communication functions, supporting Internet access and LAN wireless communication; connecting to various variable irrigation controllers through LAN wireless communication, issuing irrigation volume targets for each plot, and obtaining current pressure data for each sprinkler head; receiving irrigation prescription maps from the network platform through Internet access, and the information in the irrigation prescription maps is the irrigation volume for each plot to be irrigated.

[0017] The variable irrigation control method of a large sprinkler disclosed in the present invention has the following beneficial effects:

[0018] (1) The variable irrigation control method for large sprinkler irrigation machines of the present invention takes into account the mutual influence between the flow rates of all nozzles on the sprinkler irrigation machine, and constructs a decision network using wireless communication and edge computing methods, which can quickly stabilize the flow rates of each nozzle on the entire sprinkler irrigation machine at the target value.

[0019] (2) The present invention adopts an independent artificial intelligence control solution of edge computing, eliminating the limitation on the number of devices. That is, when the number of sprinklers is increased or decreased, only the corresponding independent variable irrigation controller needs to be added, and there is no need to rebuild the overall control method and control model. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the calculation results of the irrigation volume of the traditional sprinkler irrigation area;

[0021] Figure 2 This is a flow chart of the traditional nozzle flow regulation method based on PWM control.

[0022] Figure 3 It is a schematic diagram of the device installation structure of the present invention;

[0023] Figure 4 This is a schematic structural diagram of the variable irrigation controller of the present invention;

[0024] Figure 5 This is a schematic structural diagram of the intelligent calculation model for the valve opening of the present invention.

[0025] Among them, in the figure:

[0026] 1 - Variable irrigation controller; 2 - Truss; 3 - Sprinkler head; 4 - Irrigation gateway; 5 - Main tower vehicle. Specific implementation manners

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0028] Refer to Figure 3 , a variable irrigation control method for a large-scale sprinkler disclosed by the present invention includes: adjusting the irrigation water volume of each sprinkler head by installing a variable irrigation controller on each sprinkler head of the sprinkler, forming a network among the variable irrigation controllers through wireless communication, and realizing real-time adjustment of the valve opening through the valve opening adjustment algorithm built in the variable irrigation controller, so that the water output of the sprinkler head quickly and stably reaches the target water output required by the irrigation prescription map.

[0029] Further optimizing the technical solution, the variable irrigation controller 1 is installed on each sprinkler branch pipe on the truss 2; the variable irrigation controller 1 realizes Internet access by accessing the irrigation gateway 4 installed on the main tower vehicle 5.

[0030] Further optimizing the technical solution, refer to Figure 4 , the variable irrigation controller mainly consists of a ball valve for controlling the opening and closing of the irrigation branch pipe, a ball valve control component with adjustable opening, a pressure sensor, and a control circuit; among them, the ball valve for controlling the opening and closing of the branch pipe is connected to the truss and the sprinkler branch pipe, and opening the ball valve can deliver water to the sprinkler head; the opening and closing of the ball valve are controlled by the ball valve control component with adjustable opening; the pressure sensor is arranged in the sprinkler branch pipe for real-time measurement of the water pressure in the sprinkler branch pipe; the control circuit is respectively communicatively connected to the ball valve control component and the pressure sensor.

[0031] To further optimize the technical solution, the ball valve control assembly is mainly composed of a motor, a reduction gear and a position sensor; wherein, the output end of the motor is connected to the ball valve through the reduction gear, and the opening of the ball valve is adjusted by the rotation of the motor; the position sensor is used to feedback the opening of the ball valve, and the opening degree of the ball valve can be accurately controlled by the position sensor.

[0032] To further optimize the technical solution, the control circuit in the variable irrigation controller is the core unit of the entire variable irrigation controller. It adopts a lightly simplified artificial intelligence embedded framework design. The control circuit adopts the ARM M4 series chip as the core MCU, embedded with a real-time operating system and a lightly simplified AI component. It can perform edge computing and realize edge computing of artificial intelligence algorithms. It also has acquisition, control, communication and intelligent computing functions. The acquisition function mainly acquires position sensors and pressure sensors. The control function adjusts the opening of the ball valve by controlling the rotation of the motor. The valve opening and pressure obtained in the acquisition function can be used as feedback for the control function, thereby realizing precise opening control of the ball valve. The communication function realizes the interaction of data between controllers through a local wireless network. Each variable irrigation controller can obtain data such as the current target flow rate and the current pressure of each nozzle calculated on the irrigation treatment map. The intelligent computing function calculates the control opening of the ball valve using the valve opening intelligent calculation model by obtaining the target flow rate and the current pressure of each nozzle.

[0033] To further optimize the technical solution, the irrigation gateway is a gateway device with two communication functions, supporting Internet access and LAN wireless communication; connecting to various variable irrigation controllers through LAN wireless communication, issuing irrigation volume targets for each plot, and obtaining the current pressure data of each sprinkler; receiving irrigation prescription maps from the network platform through Internet access, and the information in the irrigation prescription map is the irrigation volume for each plot to be irrigated. It also has the function of adjusting the operating speed of the sprinkler. When the current operating speed cannot meet the irrigation volume demand, it can adjust the forward speed of the sprinkler to ensure that the irrigation volume demand is met.

[0034] The opening of each valve in the variable irrigation control method of a large sprinkler of the present invention adopts a distributed edge computing method. Each valve independently calculates its own opening according to the irrigation volume requirement of the irrigation prescription map, and finally realizes the overall irrigation volume requirement of the sprinkler. First, it is necessary to establish the relationship between pressure and flow, convert the flow of the sprinkler into the pressure of the sprinkler branch pipe, and then adjust the branch pipe pressure by adjusting the valve opening to achieve the regulation of irrigation volume. The flow rate is the product of the flow rate and the sprinkler time, and the sprinkler time is the length of the plot divided by the travel speed of the sprinkler. The relationship between different sprinklers and flow rates follows different models, and the relationship between pressure and flow rate can be expressed by formula (1). The coefficients a and b can be obtained through experiments according to the different sprinklers used.

[0035] F=aPb (1)

[0036] Where F is the flow rate and P is the pressure of the sprinkler branch pipe.

[0037] Since there is a strong correlation between the branch pipe pressure and the valve opening on the same sprinkler machine, that is, at the same valve opening, the actual pressure of the sprinkler branch pipe is affected by the valve openings of other sprinkler branch pipes on the sprinkler machine. It is very difficult to obtain the actual required flow rate by using the traditional method of calculating the valve opening. The present invention provides an artificial intelligence calculation model based on a bidirectional long short-term memory network (BiLSTM), that is, a valve opening calculation model. A valve opening calculation model is provided on each core MCU. The input of the valve opening calculation model is the target flow rates of other nozzles and the target flow rate of this valve. The opening of this valve is output through the calculation of the valve opening calculation model. Since the number of nozzles simultaneously regulated on a sprinkler machine is huge, using the flow rates of all these nozzles as the input of the valve opening calculation model will result in a huge model scale. However, by using the valve opening calculation model, some nozzles with little influence on the current valve can be removed, thereby reducing the model scale and realizing lightweight edge computing. In the valve opening calculation model, the forget gate controls information removal, the input gate controls the addition of new information, and the output gate determines the output of the next state. This gating mechanism enables BiLSTM to selectively retain or ignore information, thereby improving the learning ability. Its structure is as Figure 5 shown.

[0038] The forget gate is responsible for determining which information should be discarded, removing redundant nozzle flow rate information. The forget gate f t The calculation formula is shown in formula (2):

[0039] f t =σ(W f ·[h t-1 ,x t +b f ) (2)

[0040] Where σ is the sigmoid function, W f is the forget gate weight matrix, h t-1 is the previous input of the cell, x t is the current input of the cell, and b f is the forget gate bias term.

[0041] The input gate determines which nozzle flow rate information is added to the cell state, as shown in formulas (3) and (4):

[0042] i t =σ(W i ·[h t-1 ,x t +b i) (3)

[0043]

[0044] Among them, σ is the sigmoid function, and W i is the weight matrix of the input gate, h t-1 is the previous input of the cell, x t is the input of the current cell, b i is the bias term of the input gate, W C is the weight matrix for calculating the cell state, b C is the bias term for calculating the cell state.

[0045] The current cell state C t is the previous cell state C t-1 multiplied by the output of the forget gate, plus the new candidate value multiplied by the output of the input gate i t , as shown in formula (5):

[0046]

[0047] The output gate controls the information flow from the cell state to the hidden state, and the calculation formulas are as shown in formulas (6) and (7):

[0048] o t = σ(W o ·[h t-1 , x t +b o ) (6)

[0049] h t = o t *tanh(C t ) (7)

[0050] Among them, o t is the current output, W o is the weight matrix of the output gate, b o is the bias term of the output gate.

[0051] Due to the limitation of the main pipeline flow rate of the sprinkler irrigation machine, in some cases, it may be impossible to reach the irrigation flow rate target. Therefore, an external attention mechanism is introduced, and the limiting conditions are used to adjust the model output of the external attention mechanism.

[0052] Finally, the valve opening calculation model is deployed on each variable irrigation controller, and each variable irrigation controller performs more accurate flow regulation through edge computing considering the flow rate targets and opening states of other valves.

[0053] The variable irrigation control method of the large-scale sprinkler of the present invention is constructed by using the method of distributed edge computing. A variable irrigation controller is installed on each valve of the sprinkler. The controller can obtain the flow rates of other valves on the same sprinkler and calculate the valve opening degree by using the intelligent method of edge computing. The present invention is designed with a lightweight artificial intelligence framework. While adopting a real-time operating system, a lightweight AI support component is added, enabling the operation of artificial intelligence algorithms on the controller. The present invention constructs a valve opening degree calculation model by using a bidirectional long short-term memory network. While ensuring accurate calculation, excessive redundant information is discarded, reducing the algorithm complexity and meeting the edge computing requirements of the algorithm on the variable irrigation controller. The present invention can realize the independent adjustment of the flow rate of a single valve, achieve the real-time adjustment of the irrigation amount of each valve according to the irrigation prescription map, and improve the uniformity of sprinkler irrigation.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements for some of the technical features. However, such modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A variable irrigation control method for a large sprinkler, characterized in that: include: The water volume of the sprinkler can be adjusted by installing a variable irrigation controller on each sprinkler. A wireless communication network is used between the variable irrigation controllers. The valve opening adjustment algorithm built into the variable irrigation controller can be used to adjust the valve opening in real time, so that the water output of the sprinkler can be quickly stabilized at the target water output required by the irrigation prescription map.

2. A variable irrigation control method for a large sprinkler according to claim 1, characterized in that: The variable irrigation controller (1) is installed on each branch pipe of a sprinkler head (3) on a truss (2); the variable irrigation controller (1) is connected to the Internet by accessing an irrigation gateway (4) installed on a main tower vehicle (5).

3. A variable irrigation control method for a large sprinkler according to claim 2, characterized in that: The variable irrigation controller is mainly composed of a ball valve for controlling the switch of the sprinkler branch pipe, a ball valve control component with adjustable opening, a pressure sensor and a control circuit; wherein the ball valve for controlling the switch of the branch pipe is connected to the truss and the sprinkler branch pipe, and opening the ball valve can deliver water to the sprinkler; the switch of the ball valve is controlled by the ball valve control component with adjustable opening; the pressure sensor is arranged in the sprinkler branch pipe for measuring the water pressure in the sprinkler branch pipe in real time; the control circuit is respectively connected to the control of the ball valve control component and the pressure sensor for communication.

4. A variable irrigation control method for a large sprinkler according to claim 3, characterized in that: The ball valve control assembly is mainly composed of a motor, a reduction gear and a position sensor; wherein the output end of the motor is transmission-connected to the ball valve through the reduction gear, and the opening of the ball valve is adjusted by the rotation of the motor; the position sensor is used to feedback the opening of the ball valve.

5. A variable irrigation control method for a large sprinkler according to claim 4, characterized in that: The control circuit adopts ARM M4 series chip as the core MCU, embedded with real-time operating system and simplified AI components.

6. A variable irrigation control method for a large sprinkler according to claim 5, characterized in that: A valve opening calculation model is provided on each core MCU. The input of the valve opening calculation model is the target flow of other nozzles and the target flow of the valve. The opening of the valve is output through the calculation of the model.

7. A variable irrigation control method for a large sprinkler according to claim 6, characterized in that: In the valve opening calculation model, the forget gate controls the removal of information, the input gate controls the addition of new information, and the output gate determines the next state output.

8. A variable irrigation control method for a large sprinkler according to claim 7, characterized in that: The irrigation gateway is a gateway device with two communication functions, supporting Internet access and LAN wireless communication; connecting to various variable irrigation controllers through LAN wireless communication, issuing irrigation volume targets for each plot, and obtaining the current pressure data of each sprinkler; receiving irrigation prescription maps from the network platform through Internet access. The information in the irrigation prescription maps is the irrigation volume for each plot to be irrigated.

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