Precise targeting variable pesticide application control system and method of plant protection unmanned aerial vehicle for prescription map grid boundary

Abstract

The invention discloses a precise targeting variable pesticide application system of a plant protection unmanned aerial vehicle for a prescription map grid boundary and a control method. The system comprises an information acquisition module, a pesticide application execution module, a pesticide application control module and a folding spray rod. Before the plant protection unmanned aerial vehicle enters an operation route, the pesticide application control system analyzes data of the laser ranging radar to obtain height information, and the folding spraying rod is unfolded after the safe operation height is reached, so that spraying control is optimized. In the operation process, the pesticide application control system obtains latitude and longitude information of the unmanned aerial vehicle through the RTK positioning unit, calculates coordinates of the folding spraying rod and compares the coordinates with grid boundaries of a prescription map. When the distance reaches a dynamic pesticide application delay compensation threshold value, the duty ratio of the peristaltic pump is adjusted, precise target variable pesticide application is achieved, the pesticide application precision is improved, and the pesticide and fertilizer dosage is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of precision pesticide application control of plant protection UAVs, and in particular relates to a system and a control method for precisely targeting variable pesticide application by a plant protection UAV based on grid boundaries of a prescription map. Background Art

[0002] Drone pesticide application technology, a key component of precision agriculture, has experienced rapid development in recent years and is widely used globally for applications such as farmland pest control and fertilizer spraying. Its core advantage lies in its ability to efficiently and accurately complete pesticide application tasks, reducing pesticide usage and environmental pollution. Currently, most crop protection drones utilize Beidou or RTK high-precision positioning technology, combined with pre-set flight paths for automated operation. Furthermore, some advanced models are equipped with multispectral sensors and AI algorithms, enabling real-time monitoring of crop health and adjusting pesticide application strategies, further enhancing the precision and intelligence of pesticide application. However, despite these technological advancements, existing drone pesticide application systems still face numerous challenges.

[0003] In existing drone-based pesticide application technology, the distance between the nozzle and the crop canopy is relatively large, increasing the time droplets spend drifting in the rotor downwash, leading to a series of significant technical problems. First, as the spray droplets fall from the nozzle to the crop canopy, they are susceptible to interference from both the drone's rotor downwash and the natural wind field, resulting in uncontrollable droplet drift distance and significant loss of pesticide solution. This not only reduces pesticide utilization and increases application costs, but can also cause the pesticide solution to drift to non-target areas, contaminating the surrounding environment or crops, and even negatively impacting the ecosystem. Second, because the droplets remain in the air for too long, some fine droplets evaporate before reaching the crop canopy, further reducing the effective deposition of the pesticide solution and affecting the control effect. Furthermore, excessive nozzle distance reduces the droplet's penetration ability, making it difficult for the pesticide solution to reach the lower and middle layers of the crop leaves. This is especially true for densely planted crops such as rice and wheat, where blind spots are likely to occur, reducing the overall effectiveness of the application. Finally, to compensate for the ineffective application caused by the nozzle being too far away, operators often increase the amount of pesticide applied or the flight speed. This not only increases operating costs but also risks pesticide damage, creating a vicious cycle. Therefore, the nozzle being too far away from the crop canopy is one of the key factors limiting the effectiveness of drone pesticide application.

[0004] In existing drone spraying operations, the fixed spray boom structure has significant technical limitations: First, the unfolded shape of the spray boom in the non-operating state makes the entire machine bulky, which is prone to collision damage during transportation and storage in complex farmland environments, especially when passing through narrow spaces such as fruit tree areas and power line areas, which poses a safety risk. Second, traditional spray booms mostly adopt an integrated design. After local damage, they need to be replaced as a whole, which has high maintenance costs and affects the continuity of operations. Third, the distance between the nozzle at the end of the traditional spray boom and the crop canopy is large. The spray droplets are affected by the superposition of the downwash airflow of the drone rotor and the natural wind field, resulting in uncontrollable droplet drift distance and large-scale loss of liquid medicine. At the same time, in order to ensure flight safety, the operating altitude cannot be further lowered, resulting in a contradictory problem between spraying accuracy and flight safety. Summary of the Invention

[0005] The present invention provides a variable-target spraying system and control method for plant protection UAVs targeting the grid boundaries of prescription maps, which can solve the technical problems of droplet deposition delay caused by the spraying response of the spraying system and the spraying droplet deposition time when existing UAVs are operating at high speed, and the insufficient spraying accuracy of plant protection UAVs targeting the grid boundaries of prescription maps.

[0006] To solve the above problems, the present invention provides the following technical solutions:

[0007] The embodiment of the present invention provides a plant protection UAV precise target variable spraying system for the grid boundary of a prescription map, comprising an information acquisition module, a spraying execution module, a spraying control module, and a folding spray boom; the information acquisition module comprises an RTK positioning module, a flow sensor, a pressure sensor, and a data transmission module; the spraying execution module comprises a peristaltic pump, an overflow valve, a solenoid valve, a plant protection nozzle (9), and a spraying pipeline, the peristaltic pump is connected to the plant protection nozzle (9) through the spraying pipeline, the overflow valve is installed on the spraying pipeline, the plant protection nozzle (9) is installed with a solenoid valve, and the plant protection nozzle (9) is installed on the folding spray boom. The pesticide application control module calculates the real-time longitude and latitude coordinates of the folding spray boom (9) based on the longitude and latitude positioning information of the plant protection UAV collected by the RTK positioning module in the information collection module, combined with the relative position information of the folding spray boom (9) of the plant protection UAV and the RTK positioning module, and then calculates the real-time distance between the folding spray boom (9) and the corresponding variable pesticide application grid boundary using the Haversing formula according to the real-time longitude and latitude coordinates of the folding spray boom (9) and the longitude and latitude coordinates of the variable pesticide application grid boundary. When the distance reaches the corresponding dynamic pesticide application delay compensation distance, the output duty cycle of the peristaltic pump is controlled to complete the pesticide application operation at the variable pesticide application grid boundary.

[0008] In a preferred embodiment of the present invention, the folding spray boom module comprises a folding spray boom, a crossbar, a crossbar connector (1), a rotating head fixing member (2), a base (3), a rotating head support plate (4), a rotating head (5), a carbon fiber rod (6), a spray head connector (7), a clamp (8), a steering gear fixing member (10) and a folding steering gear (11); the crossbar connector (1) is connected to the base (3) by bolts, the steering gear fixing member (10) fixes the folding steering gear (11) on the base (3), and the steering gear fixing member (10) is connected to the base (3) by bolts; the rod connector (5) is connected to the steering gear plate The servo disc and the folding servo (11) are connected by threads, and torque is transmitted through gears and gear discs. The rod connecting member (5) and the rod connecting fixing member 1 (2) are connected by bearings. The first rod connecting fixing member (2) and the rod connecting fixing member 2 (4) are connected to the base (3) by bolts. The rod connecting member (5) and the carbon fiber rod (6) are connected by the clamp (8). The plant protection nozzle (9) and the carbon fiber rod (6) are connected by the nozzle connecting member (7) and fixed by the clamp (8). The folding spray rod is connected to the cross rod by the cross rod connecting member (1), so as to be carried on the plant protection UAV.

[0009] In a preferred embodiment of the present invention, the folding spray boom can reduce the distance between the nozzle and the crop canopy, thereby weakening the influence of the downwash airflow and the natural wind field on the deposition of the spraying droplets of the plant protection UAV rotor, improving the controllability of the droplet drift distance, and is a core component for reducing the delay distance of the spraying droplet deposition. Before the plant protection UAV enters the variable spraying route operation, the spraying control module receives and analyzes the laser ranging radar data to obtain the height information of the plant protection UAV. When the preset safe operating height is reached, the folding steering gear (11) is controlled to rotate 90 degrees, and the folding spray boom is deformed from the horizontal state to the unfolded state.

[0010] In a preferred embodiment of the present invention, the RTK positioning module, serving as the core component for positioning a plant protection drone, consists of a base station and a rover. The base station, fixed at a known coordinate point on the ground, receives satellite signals, calculates errors, and transmits these error correction data to the rover via wireless data transmission. The rover performs high-precision calculations based on the satellite signals it receives. The microcontroller in the pesticide application control module reads and analyzes the mobile station's high-precision positioning data to obtain the plant protection drone's real-time, high-precision latitude and longitude information.

[0011] An embodiment of the present invention provides a method for controlling variable pesticide application by a plant protection drone based on the grid boundaries of a prescription map. The method is implemented using a system for precisely applying variable pesticides to a plant protection drone based on the grid boundaries of a prescription map according to the above embodiment, and includes the following steps:

[0012] (1) Spray boom deployment stage: Before the plant protection UAV enters the starting point of the spraying operation route, the single-chip microcomputer reads and analyzes the data of the laser ranging radar to obtain the real-time flight altitude. When the safe operating altitude is reached, the folding spray boom is controlled to deform from the horizontal state to the deployed state.

[0013] (2) Coordinate calculation and dynamic delay compensation: After the plant protection UAV enters the flight line operation, the single chip parses the RTK mobile station module data, obtains the longitude and latitude coordinates of the plant protection UAV, and calculates the longitude and latitude coordinates of the folding spray boom (9) based on the relative position relationship between the folding spray boom and the RTK mobile station module; the Haversing formula is used to calculate the real-time distance between the folding spray boom (9) and the boundaries of each variable spraying grid; when the distance reaches the dynamic delay compensation distance threshold, the peristaltic pump output duty cycle is controlled to complete the variable spraying operation at the boundary of the variable spraying grid.

[0014] A preferred embodiment of the present invention uses the Haversine formula to calculate the great circle distance between two points on the Earth's surface. The great circle distance is the distance between two points along the shortest path on the Earth's surface, where this shortest path is a great circle arc on the Earth. The steps for using this formula to calculate the distance between two points are as follows:

[0015] (1) Determine the longitude and latitude of two points: Set the coordinates of the two points to point A (lat1, lon1) and point B (lat2, lon2), where latitude (lat) and longitude (lon) are angles in radians.

[0016] (2) Calculate the difference between latitude and longitude: Calculate the difference between the latitude of point A and point B Δlat = lat2-lat1 and the difference between the longitudes Δlon = lon2-lon1.

[0017] (3) Apply the Haversine formula: a = sin(Δlat / 2) 2 +cos(lat2)·cos(lat2)·sin(Δlon / 2) 2 ;calculate Calculate the average radius R of the Earth; the great circle between two points d = R·c.

[0018] A preferred embodiment of the present invention further includes the following:

[0019] (1) Determination of the relationship between flight speed and spraying delay: Under the same flight altitude of the plant protection UAV, the spraying droplet deposition delay distance corresponding to different flight speeds (1.0, 1.5, 2.0, 2.5, 3.0 m / s) was measured.

[0020] (2) Dynamic prescription map grid boundary spraying control process: The spraying control system microcontroller receives and analyzes the high-precision positioning data output by the RTK mobile station to obtain the real-time longitude and latitude coordinates of the plant protection UAV, and uses Gaussian projection to convert the real-time longitude and latitude coordinates of the plant protection UAV (L Z ,λ Z ) is converted to plane coordinates (X Z , Y Z ). According to the relative position of the spray boom and the RTK mobile station module, the offset of the spray boom relative to the RTK mobile station module (Δx, Δy, Δz) is calculated; the coordinates of the spray boom (X P =X Z +Δx,Y P =Y Z +Δy); finally, the plane coordinates of the boom are converted into longitude and latitude coordinates (L P ,λ P The real-time distance between the spray boom's real-time longitude and latitude coordinates and the preset system's variable spraying grid's boundary longitude and latitude coordinates is calculated using the Haversing formula. When the distance reaches the dynamic delay compensation distance, the peristaltic pump output's corresponding duty cycle is controlled to complete boundary spraying control.

[0021] Compared with the prior art, the embodiments of the present invention provide a system and control method for accurately targeting variable pesticide application based on the grid boundaries of a prescription map using a plant protection drone, which has the following beneficial effects:

[0022] (1) Improvements are made to the foldable spray boom. In the existing drone spraying operations, the fixed spray boom structure has significant technical limitations. The present invention proposes an innovative solution of equipping a modular foldable spray boom. The folding function of the spray boom is achieved through the design of a servo-controlled spray boom, which significantly improves the equipment's passability and usage cost. The spray boom adopts a modular structure with standardized interfaces. Any damaged component can be disassembled and replaced separately, which improves maintenance efficiency and reduces spare parts storage costs. A high-precision servo is used as the drive component, which reduces the cost by 75% compared to the traditional drive system. While ensuring precise control of the deployment angle, it has an IP65 protection level and anti-corrosion properties, and can stably cope with high humidity and high corrosion conditions in the pesticide atomization environment. Combined with the low power consumption design, the flight time is extended to 5 hours. Its core value lies in: through a simple folding mechanism, while maintaining the safe flight altitude of the plant protection UAV, the nozzle is dynamically brought close to the crop canopy to an operating distance of 50-80cm, effectively reducing the dual interference of the plant protection UAV's downwash airflow and the natural wind field on the droplets; combined with a dynamic spraying delay compensation algorithm, the impact of the liquid injection lag during the start and stop phases of the peristaltic pump is reduced, and the target variable spraying accuracy of the prescription map grid boundary is increased to 30cm, and the effective deposition rate of the liquid is also improved. Through the coordinated optimization of the mechanical structure and control algorithm, this design breaks through the technical bottleneck of "maintaining safety" and "improving precision" in traditional plant protection UAV spraying operations, providing a solution for large-scale precision variable spraying in farmland.

[0023] (2) Improvement of the precision spraying algorithm based on dynamic delay compensation. In order to improve the spraying accuracy of the spraying system at the grid boundary of the prescription map, the present invention proposes a precision spraying algorithm based on dynamic delay compensation. The algorithm divides the spraying operation area into several grid units and measures the spraying droplet deposition delay distance of the plant protection UAV at different flight speeds in advance. Combined with real-time speed monitoring and dynamic compensation mechanism, it significantly improves the spraying accuracy and operation efficiency. Specifically, the algorithm first divides the operation area into regular grid units according to system parameters (such as spray width, medicine box capacity, etc.) and marks the boundary coordinates of each unit. Subsequently, by dynamically measuring the spraying deposition delay distance of the plant protection UAV, a mapping relationship between it and the flight speed and a database is established. In actual operation, the algorithm dynamically calculates the compensation distance according to the real-time speed, and sends the start-stop control command in advance before reaching the preset grid boundary to ensure the accurate execution of the spraying action. The core advantage of this algorithm lies in its dynamic compensation mechanism and real-time feedback calibration capability. By integrating the RTK positioning module, inertial measurement unit and flow sensor, the algorithm can monitor the equipment status in real time and automatically adjust the compensation parameters to adapt to different operating environments.

[0024] (3) The present invention provides an automatically foldable spray boom design, and in combination with an improved variable spraying algorithm based on the grid boundary of a prescription map, introduces dynamic spraying delay distance compensation to offset the spraying delay, thereby improving the grid boundary variable spraying accuracy. The folding function of the foldable spray boom facilitates the takeoff and landing of the plant protection UAV in a non-operating state, ensuring the operational safety of the UAV when operating with the spray boom. The improved variable spraying algorithm for the target of the grid boundary of the prescription map dynamically adjusts the issuance time of the spraying instruction by calculating the flight speed of the plant protection UAV and the corresponding spraying delay in real time, that is, issuing the spraying instruction in advance before reaching the target position, thereby offsetting the error caused by the spraying delay.

[0025] (4) Through the droplet deposition delay distance experiment, a database of droplet delay distances at different flight speeds is established. In plant protection operations, by monitoring the flight speed and target distance of the drone, the constructed database is used to calculate the advance amount of pesticide application required for target application, ensuring the accuracy of pesticide application by the plant protection drone at the boundary position of the prescription map grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 Schematic diagram of the partial structure of the folding spray boom module of the plant protection drone provided in an embodiment of the present application for the precise target variable spraying system based on the grid boundary of the prescription map.

[0028] Figure 2 Schematic diagram of a system method for accurately targeting variable pesticide application based on the grid boundaries of a prescription map by a plant protection drone provided in an embodiment of the present application.

[0029] Figure 3 This is a main program flow chart of the method for accurately controlling the target variable spraying of a plant protection drone based on the grid boundaries of a prescription map provided in an embodiment of the present application. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application. The "upper", "lower", "front", "back", "left", "right", etc. used in the installation position or direction of the structure or parts of the present embodiment are based on the orientation of the given drawings. They are only for the convenience of expression to distinguish the relative positions of the various parts or directions, and do not represent the orientation of the system or parts of the present embodiment when in use.

[0031] The present invention discloses a variable spraying system and control method for a plant protection UAV that precisely targets the grid boundaries of a prescription map. The system includes an information acquisition module, a spraying execution module, a spraying control module, and a folding spray boom. Before the plant protection UAV enters the starting point of the spraying operation route, the spraying control system reads and analyzes the laser ranging radar data to obtain the altitude information of the plant protection UAV. When the safe operating altitude is reached, the folding spray boom is controlled to unfold, shortening the distance between the plant protection nozzle and the crop canopy, thereby improving the controllability of the spraying droplet drift distance. During the spraying operation of the plant protection UAV, the spraying control system calculates the latitude and longitude coordinates of the folding spray boom online based on the latitude and longitude information of the plant protection UAV collected by the RTK positioning unit in the information acquisition module and the relative position relationship between the folding spray boom of the plant protection UAV and the RTK positioning unit. The distance between the folding spray boom and the grid boundary of the prescription map is obtained by combining the latitude and longitude coordinates of the grid boundary of the prescription map. When the distance reaches the dynamic spraying delay compensation distance threshold, the duty cycle of the peristaltic pump in the spraying execution module is feedback-adjusted to complete the precise target variable spraying operation at the grid boundary of the prescription map, thereby improving the spraying accuracy and reducing the amount of pesticide and fertilizer used.

[0032] like Figure 1 and Figure 2As shown, an embodiment of the present invention provides a plant protection drone system for precisely targeting variable spraying at the grid boundaries of a prescription map. The system includes a plant protection drone, an information collection module, a spray execution module, a spray control module, and a folding boom module. The information collection module includes an RTK positioning module, a flow sensor, a pressure sensor, and a data transmission module. The spray execution module includes a peristaltic pump, a relief valve, a solenoid valve, a plant protection nozzle 9, and a spray pipe. The peristaltic pump is connected to the plant protection nozzle 9 via the spray pipe, which is equipped with a relief valve. The plant protection nozzle 9 is also equipped with a solenoid valve, and the plant protection nozzle 9 is mounted at the end of the folding boom module. The spray control module calculates the longitude and latitude coordinates of the folding boom 9 based on the longitude and latitude positioning information of the plant protection drone collected by the RTK positioning unit in the information collection module and the relative position information between the folding boom 9 of the plant protection drone and the RTK positioning module. Based on the real-time longitude and latitude coordinates of the folding boom 9 and the longitude and latitude coordinates of the target variable spraying boundary, the Haversing formula is used to calculate the distance between each folding boom 9 and the corresponding grid boundary. When the distance reaches the dynamic dosing delay compensation distance, the output duty cycle of the peristaltic pump is controlled to complete the variable dosing operation at the grid boundary.

[0033] like Figure 1 As shown, the folding spray boom module includes a folding spray boom, a cross bar, a cross bar connector 1, a rotating head fixing member 2, a base 3, a rotating head support plate 4, a rotating head 5, a carbon fiber rod 6, a nozzle connector 7, a hoop 8, a servo fixing member 10 and a folding servo 11; the cross bar connector 1 is connected to the base 3 by bolts, the servo fixing member 10 fixes the folding servo 11 on the base 3, and the servo fixing member 10 is connected to the base 3 by bolts; the rod connector 5 is connected to the servo disk by threads, and the servo disk and the folding servo 11 transmit torque through gears and gear disks, the rod connector 5 and the first rod connecting fixing member 2 are connected by bearings, the first rod connecting fixing member 2 and the second rod connecting fixing member 4 are connected to the base 3 by bolts, and the rod connector 5 and the carbon fiber rod 6 are connected by a hoop 8; the plant protection nozzle 9 is connected to the carbon fiber rod 6 by the nozzle connector 7 and fixed by the hoop 8; the folding spray boom is connected to the cross bar through the cross bar connector 1, so as to be carried on the plant protection drone. A plant protection drone of this embodiment uses a precise variable spraying control system for precise targeting of prescription map grid boundaries, which is controlled by a precise variable spraying algorithm equipped with a folding spray boom and combined with dynamic spraying delay distance compensation.

[0034] The folding spray boom is a core component used to reduce the impact of rotor downwash and natural wind on pesticide droplet deposition, improve the controllability of droplet drift distance, and reduce the delay distance of pesticide droplet deposition. Before the pesticide drone enters its spraying route, the spraying control module reads and analyzes laser ranging radar data to determine the drone's flight altitude. When the altitude reaches a safe operating altitude, it controls the folding servo 11 to rotate 90 degrees, causing the folding spray boom to transform from a horizontal position to an extended position.

[0035] like Figure 2 As shown in the figure, the RTK positioning module, the core component of the agricultural drone positioning, consists of a base station and a rover. The base station is fixed at a known coordinate point on the ground, receives satellite signals, calculates errors, and transmits these error correction data to the rover via wireless data transmission. The rover combines the received satellite signals with the mobile station to perform high-precision calculations. The microcontroller in the pesticide control module receives and analyzes the mobile station's high-precision positioning data to obtain the agricultural drone's real-time latitude and longitude information.

[0036] refer to Figure 3 The embodiment of the present invention provides a method for controlling variable spraying of a plant protection drone precisely targeting the grid boundaries of a prescription map. The method is implemented using a system for precisely targeting variable spraying of a plant protection drone precisely targeting the grid boundaries of a prescription map as in the above embodiment, and includes the following steps: the plant protection drone enters the starting point of the route, the single-chip microcomputer receives and parses the data of the laser ranging radar, obtains the corresponding height of the plant protection drone, and when the height reaches the safe operating height, controls the folding spray boom to deform from a horizontal state to an unfolded state; during the operation of the plant protection drone entering the route, the single-chip microcomputer parses the RTK mobile station data to obtain the real-time longitude and latitude coordinates of the plant protection drone. Based on the relative position relationship between the folding spray boom and the RTK mobile station module, the longitude and latitude coordinates of the folding spray boom 9 are calculated, and the Haversing formula is used to calculate the real-time distance between the folding spray boom 9 and each grid boundary. When the distance reaches the dynamic delay compensation distance, the output duty cycle of the peristaltic pump is controlled.

[0037] The folding boom module consists of multiple precision mechanical components, including the folding boom, crossbar, crossbar connector 1, swivel head mount 2, base 3, swivel head support plate 4, swivel head 5, carbon fiber rod 6, nozzle connector 7, clamp 8, servo mount 10, and folding servo 11. The crossbar connector 1 is rigidly connected to the base 3 via high-strength bolts, ensuring structural stability. The servo mount 10 securely mounts the folding servo 11 to the base 3 using bolts, providing a reliable driving foundation. The swivel head 5 is connected to the servo disc via precision threads. Torque is transmitted between the servo disc and the folding servo 11 through the meshing of gears. High-precision bearings connect the swivel head 5 to the swivel head mount 2, ensuring smooth and durable rotation. The swivel head mount 2 and swivel head support plate 4 are bolted to the base 3, forming a stable support structure. The swivel head 5 is connected to the carbon fiber rod 6 via the clamp 8, which provides a reliable clamping force and ensures the stability of the carbon fiber rod 6. The plant protection nozzle 9 is connected to the carbon fiber rod 6 via the nozzle connector 7 and secured by the clamp 8 to ensure the nozzle's positioning accuracy and spraying stability. The entire folding spray boom module is connected to the crossbar via the crossbar connector 1 and ultimately mounted on the plant protection drone, achieving overall structural integration.

[0038] The folding boom is driven by a folding servo 11. The angle of the rotating head 5 is adjusted through the precise meshing of the servo disc, gears, and gear plate. When the servo receives a control signal, it rotates the servo disc, which in turn transmits torque to the rotating head 5. This rotation of the rotating head 5 around the bearings of the rotating head mount 2 drives the carbon fiber rod 6 and the crop protection nozzle 9 at its end to fold or unfold. This design allows the boom to be folded and stored during transport or when not in operation, minimizing space usage. It can then be quickly deployed during operation, ensuring both coverage and efficiency.

[0039] In order to achieve precise variable spraying, the system adopts a dynamic spraying delay compensation algorithm. The spraying control module receives the RTK positioning data provided by the information acquisition module in real time to obtain the real-time longitude and latitude coordinates of the plant protection UAV. Combined with the relative position relationship between the folding spray boom and the RTK positioning module, the real-time longitude and latitude coordinates of the end of the folding spray boom (i.e., the plant protection nozzle 9) are calculated. By comparing the real-time coordinates of the nozzle with the preset prescription map grid boundary coordinates, the real-time distance between the nozzle and the grid boundary is calculated. When the distance reaches the preset dynamic spraying delay compensation distance threshold, the spraying control module sends a control signal to the spraying execution module to adjust the output duty cycle of the peristaltic pump, accurately control the spraying amount and spraying timing of the liquid medicine, and ensure uniform coverage and effective utilization of the liquid medicine in the target area.

[0040] In actual operations, a plant protection drone equipped with a folding boom module flies to the target operation area. The information collection module monitors the drone's flight status and position data in real time. The pesticide application control module uses this data, combined with information from the prescription map, to calculate and adjust application parameters in real time. In response to control signals, the pesticide application execution module precisely controls the operating status of components such as the peristaltic pump and solenoid valve, ensuring accurate spraying according to the predetermined variable application plan. The folding boom design not only improves the drone's maneuverability and operational efficiency, but also, through a precise control system, enables precise variable application of pesticides within the prescription map grid, improving pesticide utilization and operational effectiveness.

[0041] Through the coordinated work of the above parts, the folding spray boom module of the plant protection drone realizes a complete functional chain from mechanical structure, drive control to intelligent spraying, meeting the needs of modern agriculture for precise and efficient plant protection operations.

[0042] Use the Haversing formula to calculate the great circle distance between two points on the Earth's surface. The great circle distance is the distance between two points along the shortest path on the Earth's surface, which is a great circle arc. To use this formula to calculate the distance between two points, follow these steps:

[0043] (1) Determine the longitude and latitude of two points: Set the coordinates of the two points to point A (lat1, lon1) and point B (lat2, lon2), where latitude (lat) and longitude (lon) are angles in radians.

[0044] (2) Calculate the difference between latitude and longitude: Calculate the difference between the latitude of point A and point B Δlat = lat2-lat1 and the difference between the longitudes Δlon = lon2-lon1.

[0045] (3) Apply the Haversine formula: a = sin(Δlat / 2) 2 +cos(lat2)·cos(lat2)·sin(Δlon / 2) 2 ;calculate Calculate the average radius R of the Earth; the great circle between two points d = R·c.

[0046] The method for controlling the precise target variable pesticide application of a plant protection UAV according to the grid boundary of a prescription map provided by an embodiment of the present invention further includes:

[0047] (1) Determination of the relationship between flight speed and spraying delay: Under the same flight altitude of the plant protection UAV, the spraying droplet deposition delay distance corresponding to different flight speeds (1.0, 1.5, 2.0, 2.5, 3.0 m / s) was measured.

[0048] (2) Dynamic prescription map grid boundary spraying control process: The spraying control system microcontroller receives and analyzes the high-precision positioning data output by the RTK mobile station to obtain the real-time longitude and latitude coordinates of the plant protection UAV, and uses Gaussian projection to convert the real-time longitude and latitude coordinates of the plant protection UAV (L Z ,λ Z ) is converted to plane coordinates (X Z , Y Z ). According to the relative position of the spray boom and the RTK mobile station module, the offset of the spray boom relative to the RTK mobile station module (Δx, Δy, Δz) is calculated; the coordinates of the spray boom (X P =X Z +Δx,Y P =Y Z +Δy); finally, the plane coordinates of the boom are converted into longitude and latitude coordinates (L P ,λ P The real-time distance between the spray boom's real-time longitude and latitude coordinates and the preset system's variable spraying grid boundary longitude and latitude coordinates is calculated using the Haversing formula. When the distance reaches the dynamic delay compensation distance, the peristaltic pump output corresponding duty cycle is controlled to complete the grid boundary spraying control.

[0049] Specific implementation cases and effects: In this example, a folding spray boom was designed and combined with a precise spraying algorithm with dynamic delay compensation to improve the precision of target variable spraying at the grid boundary of the prescription map. The plant protection drone equipped with a folding spray boom can minimize the distance between the plant protection nozzle and the crop canopy while ensuring a safe flight altitude, reducing the droplet deposition and drift distance caused by the unstable external environment. The precise spraying algorithm with dynamic delay compensation adjusts the spraying deposition compensation distance according to the real-time flight speed of the plant protection drone, thereby improving the spraying accuracy based on the spraying boundary of the prescription map.

[0050] Although the present invention has been disclosed above in terms of preferred embodiments, the above preferred embodiments are not intended to limit the present invention. Those skilled in the art may make various modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the scope defined in the claims.

Claims

1. A plant protection drone system for precise variable-target spraying based on the grid boundaries of a prescription map, characterized by: include: A plant protection drone, integrated with the following components: a folding spray boom module, including a crossbar, a crossbar connector, a rotating head fixture, a base, a rotating head support plate, a rotating head, a carbon fiber rod, a nozzle connector, a clamp, a servo fixture, and a folding servo. The folding spray boom is connected to the crossbar via a crossbar connector and is mounted on the plant protection drone. Information collection module, including: RTK positioning module, used to obtain the longitude and latitude coordinates of the plant protection drone in real time; Flow sensor, used to monitor the flow rate of the application liquid; Pressure sensor, used to detect the pressure of the spraying system; Data transmission module, used for wireless transmission of data; Pesticide application execution module, including: The peristaltic pump is connected to the plant protection nozzle through the pesticide application pipeline and is used to transport the pesticide liquid; Overflow valve, installed on the application pipeline, is used to control the pressure in the pipeline; Solenoid valve, installed on the plant protection nozzle, is used to control the opening and closing of the spraying; The plant protection nozzle is fixed to the end of the folding spray boom module and is used to spray pesticides; The spraying control module calculates the real-time longitude and latitude coordinates of the folding spray boom based on the longitude and latitude information of the plant protection UAV obtained by the RTK positioning module and the relative position of the folding spray boom and the RTK positioning module. It also calculates the real-time distance between the folding spray boom and the grid boundary of the prescription map based on the real-time longitude and latitude coordinates of the folding spray boom and the longitude and latitude coordinates of the grid boundary of the prescription map. When the distance reaches the dynamic spraying delay compensation distance threshold, the peristaltic pump in the spraying execution module is controlled to adjust the output duty cycle to achieve variable spraying operations.

2. The system according to claim 1, wherein: The folding servo of the folding spray boom module is connected to the rotating head support plate through the servo fixing piece, and the rotating head support plate is fixed to the cross bar through the rotating head fixing piece. The folding servo drives the rotating head to rotate around the rotating head fixing piece, thereby realizing the folding and unfolding of the carbon fiber rod to adapt to different operation requirements.

3. The system according to claim 1, wherein: The spraying control module pre-stores the longitude and latitude coordinates of the grid boundaries of the prescription map, and calculates the dynamic spraying delay compensation distance threshold based on the flight speed of the plant protection drone and the response time of the spraying system to ensure the accuracy of the spraying position; The overflow valve in the pesticide application execution module is used to release excess pressure when the pressure in the pesticide application pipeline exceeds a preset threshold value to protect the safe operation of the pesticide application system.

4. The system according to claim 1, wherein: The foldable spray boom is used to shorten the distance between the plant protection nozzle and the crop canopy, reducing the impact of natural wind and the downwash of the plant protection drone rotor on the deposition of spray droplets; The spraying control module obtains the current altitude of the plant protection UAV by reading the laser ranging radar data. When the safe spraying operation altitude is reached, the folding servo is controlled to rotate 90 degrees, so that the folding spray boom is unfolded from a horizontal state to a vertical state.

5. The system according to claim 1, wherein: The RTK positioning module consists of a base station and a mobile station. The base station is fixed at a known coordinate point on the ground, receives satellite signals and calculates errors, and transmits error correction data to the mobile station through a wireless data transmission module. The mobile station combines the satellite signals it receives with its own high-precision positioning solution and provides centimeter-level real-time positioning data.

6. The system according to claim 1, wherein: After receiving and parsing the positioning data of the mobile station, the single-chip microcomputer in the pesticide application control module calculates the real-time coordinates of the plant protection drone, and calculates the real-time coordinates of the folding spray boom based on the relative position relationship between the plant protection drone and the folding spray boom, thereby realizing variable pesticide application control.

7. A method for controlling the precise variable spraying of pesticides by a crop protection drone based on the grid boundary of a prescription map, characterized in that: The method uses a plant protection drone, a folding spray boom module, an information collection module, a pesticide execution module, and a pesticide control module, and includes the following steps: When the plant protection drone enters the starting point of the route, the microcontroller of the pesticide application control module receives and analyzes the laser ranging radar data, obtains the altitude of the plant protection drone in real time, and controls the folding spray boom to deform from the horizontal state to the unfolded state after reaching the safe operating altitude; When the plant protection drone enters the operating route, the microcontroller of the spraying control module parses the RTK mobile station data to obtain the real-time latitude and longitude coordinates of the plant protection drone, and calculates the real-time latitude and longitude coordinates of the folding spray boom based on the relative position of the folding spray boom and the RTK mobile station; The Haversing formula is used to calculate the real-time distance between the folded boom and the grid boundary of the prescription map; When the distance reaches the dynamic dosing delay compensation threshold, the output duty cycle of the peristaltic pump is adjusted by feedback to achieve flow control and complete the variable dosing operation.

8. The method according to claim 1, characterized in that Use the Haversing formula to calculate the great-circle distance between two points on the Earth's surface. The calculation steps include: Set the coordinates of two points, point A (lat1, lon1) and point B (lat2, lon2), where latitude (lat) and longitude (lon) are expressed in radians; Calculate the latitude difference Δlat = lat2 - lat1 and the longitude difference Δlon = lon2 - lon1 between point A and point B; Calculate a = sin²(Δlat / 2) + cos(lat1)*cos(lat2)*sin²(Δlon / 2); Calculate c = 2*atan2(√a,√(1-a)); Set the average radius of the earth R and calculate the great circle distance d = R*c between two points.

9. The method according to claim 1, characterized in that The delay of spray droplet deposition at different flight speeds of plant protection drones is further analyzed, including: Measure the spray droplet deposition delay distance of the plant protection UAV at flight speeds of 1.0, 1.5, 2.0, 2.5, and 3.0 m / s; The microcontroller of the pesticide application control module analyzes the high-precision positioning data output by the RTK mobile station and converts the real-time latitude and longitude coordinates (LZ, λZ) of the plant protection drone into plane coordinates (XZ, YZ) using Gaussian projection. Calculate the offset (Δx, Δy, Δz) of the folding boom relative to the RTK positioning module and obtain the boom coordinates (XP = XZ + Δx, YP = YZ + Δy); The plane coordinates of the spray boom are converted into longitude and latitude coordinates (LP, λP) using the back projection formula; The real-time distance between the spray boom and the grid boundary of the prescription map is calculated, and the output duty cycle of the peristaltic pump is adjusted according to the distance to match the variable spraying demand.

10. The method according to claim 1, characterized in that The spraying control module adjusts the peristaltic pump output in real time to optimize the spraying flow rate based on the longitude and latitude coordinates of the spray boom and the grid boundary of the prescription map, combined with a dynamic spraying delay compensation model. It also corrects the spraying accuracy of the plant protection nozzle based on RTK positioning data to ensure that the variable spraying accuracy meets the operational requirements.

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