Transverse multi-rotor plant protection unmanned aerial vehicle with double-layer vehicle arms

Abstract

The invention discloses a transverse multi-rotor plant protection unmanned aerial vehicle with double-layer vehicle arms, and belongs to the field of multi-rotor plant protection unmanned aerial vehicles, the transverse multi-rotor plant protection unmanned aerial vehicle comprises an upper vehicle arm, a lower vehicle arm and eight pairs of rotors, and the eight pairs of rotors are distributed on the upper vehicle arm and the lower vehicle arm in a transverse manner; on the right upper arm, the left lower arm and the right lower arm, the rotors are the same in size and are driven by brushless direct current motors of the same specification; the first rotor wing, the third rotor wing, the fifth rotor wing and the seventh rotor wing rotate clockwise; the second rotor wing, the fourth rotor wing, the sixth rotor wing and the eighth rotor wing rotate anticlockwise; the left spray head fixing plate and the right spray head fixing plate are installed under the rotor wings, each spray head is provided with three spray heads, pesticide in the pesticide box is pressurized through the water pump, atomized and sprayed out through the six pesticide spray heads through the liquid conveying pipe, and sprayed to farmland in an accelerated mode through downwash airflow of the eight pairs of rotor wings, and plant protection operation is completed. The transverse multi-rotor plant protection unmanned aerial vehicle with the double-layer vehicle arms is better in aerodynamic performance and plant protection efficiency.

Description

Technical Field

[0001] The invention relates to the field of multi-rotor plant protection UAVs, and in particular to a transverse multi-rotor plant protection UAV with double-layer machine arms. Background Art

[0002] A multi-rotor agricultural drone is a small unmanned aerial vehicle specially designed for agricultural plant protection tasks. It is usually equipped with multiple electric motors that drive propellers to generate lift, allowing the drone to hover, move forward, move backward, and fly sideways in the air. The main function of a multi-rotor agricultural drone is to help farmers spray pesticides, apply fertilizers, sow seeds, and other operations to increase crop yields and quality. Multi-rotor agricultural drones have the following advantages:

[0003] (1) Improved efficiency: Multi-rotor agricultural drones can quickly cover large areas of farmland, greatly improving operational efficiency. Compared with manual spraying, drones can complete operations over larger areas in a short period of time, reducing labor costs.

[0004] (2) Precision application: Using GPS positioning systems and advanced flight control systems, multi-rotor agricultural drones can achieve precise positioning, ensuring that pesticides, fertilizers, etc. can be applied accurately to the required locations, reducing waste and lowering the impact on the environment.

[0005] (3) Reduce manpower requirements: Using drones for plant protection work can significantly reduce the demand for manpower, especially when working in harsh environments such as high temperature and high humidity. It reduces the risk of farmers directly coming into contact with pesticides and ensures the safety of personnel.

[0006] (4) Strong adaptability: Multi-rotor agricultural drones are small in size and light in weight. They can flexibly move between different terrains and crops and are suitable for farmlands of various sizes and different crop types.

[0007] (5) Data collection and analysis: Modern agricultural drones are usually equipped with high-definition cameras and other sensors that can collect real-time information on farmland, such as crop growth conditions, pest and disease occurrence, etc., providing a scientific basis for decision-making in agricultural production.

[0008] (6) Environmental protection and energy saving: Precision application of pesticides can reduce the excessive use of chemicals, which not only saves resources but also helps reduce environmental pollution. In addition, the use of drones also reduces soil compaction, which helps maintain soil health.

[0009] (7) Reduce production costs: In the long run, although the initial investment may be relatively high, the application of multi-rotor agricultural drones can effectively reduce overall production costs, including labor costs, chemical costs, etc., and improve the economic benefits of agricultural production.

[0010] In summary, multi-rotor agricultural drones play an important role in improving agricultural production efficiency, ensuring the quality of agricultural products, and promoting sustainable agricultural development. With the advancement of technology, these devices will become more intelligent and efficient in the future, bringing more possibilities to modern agriculture.

[0011] However, traditional multi-rotor agricultural drones mainly adopt quad-rotor, hex-rotor or oct-rotor designs, which arrange rotors at four, six or eight diagonal positions of the drone to form a square, hexagonal or octagonal layout. This layout makes the airflow between the rotors significantly affect each other, which not only weakens the aerodynamic performance of the drone and reduces the effective pesticide load it can carry, but also leads to overlap during the spraying process, shortening the effective spraying width of the drone, thereby reducing the efficiency and quality of plant protection operations. Summary of the invention

[0012] In view of the difficult problems faced by the above-mentioned traditional multi-rotor plant protection UAV, the present invention designs a transverse multi-rotor plant protection UAV with double-layer arms.

[0013] The present invention is achieved in that:

[0014] A double-layer arm horizontal multi-rotor plant protection drone, the horizontal multi-rotor plant protection drone includes an upper and lower arm, and eight rotors, the eight rotors are distributed on the upper and lower arms in a horizontal row; the upper and lower arms include a left upper arm, a right upper arm, a left lower arm, and a right lower arm; the eight rotors include a first rotor, a second rotor, a third rotor, a fourth rotor, a fifth rotor, a sixth rotor, a seventh rotor, and an eighth rotor; the first rotor, the second rotor, the third rotor, the fourth rotor, the fifth rotor, the sixth rotor, the seventh rotor, and the eighth rotor are a total of eight rotors The upper layer is distributed in a horizontal row on the left upper arm, the right upper arm, the left lower arm, and the right lower arm. Each rotor is the same size and is driven by a brushless DC motor of the same specification; the first rotor, the third rotor, the fifth rotor, and the seventh rotor rotate clockwise; the second rotor, the fourth rotor, the sixth rotor, and the eighth rotor rotate counterclockwise; the left nozzle fixing plate and the right nozzle fixing plate are installed directly below the rotors, and each has three nozzles. The pesticide in the pesticide box is pressurized by a water pump, sprayed out in atomization by six pesticide nozzles through an infusion pipe, and accelerated by the downwash airflow of the eight rotors to spray onto the farmland, completing the plant protection operation.

[0015] Furthermore, the rotors installed on the upper and lower arms are respectively clamped and fixed with the upper mounting plate and the lower mounting plate, and the left upper arm and the right upper arm are consistent and symmetrical in shape; the left lower arm and the right lower arm are tightened and fixed by the upper body mounting plate and the lower body mounting plate, and the left lower arm and the right lower arm are consistent and symmetrical in shape.

[0016] Furthermore, the upper mounting plate is used to place the avionics equipment of the UAV; at the same time, the upper fuselage mounting plate is used to place batteries to provide power for the brushless DC motor, nozzle and avionics equipment of the rotor.

[0017] Furthermore, the landing gear is fixed to the bottom surface of the lower body mounting plate, and a pesticide box and a nozzle fixing plate are installed on the landing gear. The nozzle fixing plate is divided into a left nozzle fixing plate and a right nozzle fixing plate, each of which is equipped with three nozzles for spraying pesticides. The nozzle fixing plate reinforcement (left nozzle fixing plate reinforcement, right nozzle fixing plate reinforcement) connects the landing gear and the nozzle fixing plate, which can reduce the degree of bending of the nozzle fixing plate due to gravity.

[0018] Furthermore, the upper arm (left upper arm and right upper arm) and the lower arm (left lower arm and right lower arm) are connected by four arm connecting rods and four mounting plate fixing rods. The left arm reinforcement plate and the right arm reinforcement plate are respectively installed at the left and right ends of the arm, which play the role of connecting the upper arm and the lower arm, and at the same time prevent the upper arm from breaking due to excessive bending moment.

[0019] The present invention provides a double-layer arm horizontal multi-rotor plant protection UAV, characterized in that the flight control method of the horizontal multi-rotor plant protection UAV is as follows:

[0020] 1) Forward flight: The second and fifth rotors increase their rotation speed (increase the pulling force), while the first and sixth rotors decrease their rotation speed (decrease the pulling force). At this time, the drone generates a nose-down moment. The drone flies with its head down, and the rotors generate a forward component force to overcome the forward resistance of the drone and achieve forward flight.

[0021] 2) Backward flight: The second and fifth rotors reduce their rotation speed (thrust decreases), while the first and sixth rotors increase their rotation speed (thrust increases). At this time, the drone generates a nose-up moment, the drone flies upward, and the rotors generate a backward component force to overcome the drone's backward resistance and achieve backward flight;

[0022] 3) Left-side flight: The first and second rotors reduce their rotation speed (thrust decreases), while the fifth and sixth rotors increase their rotation speed (thrust increases). At this time, the drone generates a counterclockwise rolling moment, the drone rolls counterclockwise, and the rotor generates a left component force to overcome the left resistance of the drone, thus achieving left-side flight.

[0023] 4) Right-side flight: The first and second rotors increase their rotation speed (increase the pulling force), and the fifth and sixth rotors decrease their rotation speed (decrease the pulling force). At this time, the drone generates a clockwise rolling moment, the drone rolls clockwise, and the rotor generates a right component force to overcome the right resistance of the drone and achieve left-side flight;

[0024] 5) Clockwise yaw: The speed of the second rotor, the fourth rotor, the sixth rotor, and the eighth rotor increases (the clockwise anti-torque increases), the anti-torque balance of the drone is broken, and the drone generates a clockwise torque, resulting in clockwise yaw motion;

[0025] 6) Counterclockwise yaw: The rotation speeds of the first rotor, the third rotor, the fifth rotor, and the seventh rotor increase (the counterclockwise anti-torque increases), the anti-torque balance of the drone is broken, and the drone generates a counterclockwise torque, resulting in a counterclockwise yaw motion;

[0026] 7) Ascent: The eight rotors simultaneously increase the rotor speed (increase the pulling force), the total pulling force of the rotors increases, overcoming the gravity and resistance of the drone, and the drone flies upwards;

[0027] 8) Descending: The eight rotors reduce the rotor speed at the same time (thrust decreases), the total rotor thrust decreases, and if it is less than the gravity of the drone, it will fly downward.

[0028] Furthermore, the eight rotors of the horizontal multi-rotor plant protection UAV have the same initial rotation speed; the first rotor, the third rotor, the fifth rotor, and the seventh rotor rotate clockwise; and the second rotor, the fourth rotor, the sixth rotor, and the eighth rotor rotate counterclockwise.

[0029] Compared with the prior art, the present invention adopts the above technical solution and has the following technical effects:

[0030] (1) Improved aerodynamic efficiency: The double-layer arm design can optimize the airflow distribution between the rotors and reduce the airflow interference between the rotors, thereby improving the aerodynamic efficiency of the entire system. This helps to improve the flight performance of the drone, including endurance and load capacity.

[0031] (2) Increase effective spraying width: Since the double-layer design can more effectively manage the rotor layout and reduce the problem of uneven spraying caused by airflow interference between rotors, it can achieve a wider effective spraying width and improve the coverage and efficiency of plant protection operations.

[0032] (3) Enhanced stability and controllability: The double-layer arm structure provides the UAV with better stability, especially in strong winds or complex environments. This not only improves the operational safety of the UAV, but also enables the operator to more accurately control the UAV for plant protection operations.

[0033] (4) Optimizing space utilization: The double-layer design can accommodate more rotors or larger rotor diameters without increasing the overall volume, which is very beneficial for improving the lift and carrying capacity of the UAV.

[0034] (5) Adapting to diverse operational needs: Due to the above advantages, the double-layer arm horizontal multi-rotor agricultural drone can better adapt to the operational needs of different crop types and field conditions, providing more flexible and efficient agricultural solutions.

[0035] The double-layer arm horizontal multi-rotor plant protection drone of the present invention has a special double-layer horizontal rotor distribution, which can install more rotors and reduce the airflow interference between each pair of rotors, so the effective spraying width of the pesticide becomes longer. Compared with the traditional multi-rotor plant protection drone, the aerodynamic performance and plant protection efficiency of the double-layer arm horizontal multi-rotor plant protection drone of the present invention are better. Through experiments and theoretical calculations, it is measured that the lift of the horizontal multi-rotor plant protection drone with double-layer arms of the same size in the hovering state is 14% higher than that of the traditional multi-rotor plant protection drone, while the required power is reduced by 7%, and the effective spray width of the pesticide is increased by 50%, indicating that the aerodynamic performance and plant protection operation efficiency of the double-layer arm horizontal multi-rotor plant protection drone are better than those of the traditional multi-rotor plant protection drone. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a general diagram of a double-layer arm horizontal multi-rotor agricultural drone;

[0037] Figure 2 This is a side view of a double-layered arm horizontal multi-rotor agricultural drone;

[0038] Figure 3 This is the main view of a double-layer arm horizontal multi-rotor agricultural drone;

[0039] Figure 4 This is a top view of a double-layered multi-rotor agricultural drone.

[0040] In the figure, 1-the first rotor, 2-the second rotor, 3-the third rotor, 4-the fourth rotor, 5-the fifth rotor, 6-the sixth rotor, 7-the seventh rotor, 8-the eighth rotor, 9-the left arm reinforcement plate, 10-the right arm reinforcement plate, 11-the left upper arm, 12-the right upper arm, 13-the left lower arm, 14-the right lower arm, 15-the left nozzle fixing plate, 16-the right nozzle fixing plate, 17-the nozzle, 18-the arm connecting rod, 19-the left nozzle fixing plate reinforcement, 20-the right nozzle fixing plate reinforcement, 21-the pesticide box, 22-the infusion pipe, 23-the water pump, 24-the landing gear, 25-the mounting plate fixing rod, 26-the upper mounting plate, 27-the lower mounting plate, 28-the upper body mounting plate, 29-the lower body mounting plate. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail by enumerating examples below. It should be noted that the specific implementation described here is only used to explain the present invention and is not used to limit the present invention.

[0042] The invention provides a double-layer arm horizontal multi-rotor plant protection drone, which is mainly composed of rotors, a left arm reinforcement plate 9, a right arm reinforcement plate 10, a left upper arm 11, a right upper arm 12, a left lower arm 13, a right lower arm 14, a left nozzle fixing plate 15, a right nozzle fixing plate 16, a nozzle 17, an arm connecting rod 18, a left nozzle fixing plate reinforcement 19, a right nozzle fixing plate reinforcement 20, a pesticide box 21, an infusion pipe 22, a water pump 23, a landing gear 24, a mounting plate fixing rod 25, an upper mounting plate 26, a lower mounting plate 27, an upper body mounting plate 28, a lower body mounting plate 29, etc. The main feature is that eight rotors are distributed in a horizontal row on the upper and lower arms, each rotor is the same size, and is driven by a brushless DC motor of the same specification. Six pesticide spray heads 17 are installed under the rotors. The pesticide in the pesticide box 21 is pressurized by the water pump 23, sprayed out by the six pesticide spray heads 17 through the infusion pipe 22, and sprayed on the farmland by the downwash airflow of the eight rotors. The upper and lower arms are respectively equipped with four rotors. The upper left arm 11 and the right upper arm 12 are clamped and fixed by the upper mounting plate 26 and the lower mounting plate 27. The left upper arm 11 and the right upper arm 12 are consistent and symmetrical in shape. The upper body mounting plate 28 and the lower body mounting plate 29 tighten the left lower arm 13 and the right lower arm 14. The left lower arm 13 and the right lower arm 14 are consistent and symmetrical in shape. The upper arm (left upper arm 11 and right upper arm 12) and the lower arm (left lower arm 13 and right lower arm 14) are connected by four arm connecting rods 18 and four mounting plate fixing rods 25. The left arm reinforcement plate 9 and the right arm reinforcement plate 10 are respectively installed at the left and right ends of the arm, which play the role of connecting the upper arm and the lower arm, and at the same time prevent the upper arm from breaking due to excessive bending moment. The upper mounting plate 26 is used to place the avionics equipment of the unmanned aerial vehicle (such as flight control computer, navigation equipment, data transmission radio, etc.). At the same time, the upper body mounting plate 28 can be placed with batteries to provide power for the brushless DC motor, nozzle 17 and avionics equipment of the rotor. The landing gear 24 is fixed to the bottom surface of the lower body mounting plate 29. The pesticide box 21 and the nozzle fixing plate are installed on the landing gear 24. The nozzle fixing plate is divided into a left nozzle fixing plate 15 and a right nozzle fixing plate 16, each of which is installed with three nozzles 17 for spraying pesticides. The nozzle fixing plate reinforcement connects the landing gear 24 and the nozzle fixing plate, which can reduce the degree of bending of the nozzle fixing plate due to gravity.

[0043] The present invention is described below with reference to specific embodiments:

[0044] like Figure 1As shown, a double-layer arm horizontal multi-rotor agricultural drone, which is mainly characterized by a first rotor 1, a second rotor 2, a third rotor 3, a fourth rotor 4, a fifth rotor 5, a sixth rotor 6, a seventh rotor 7, and an eighth rotor 8, a total of eight rotors are arranged in a horizontal arrangement on the upper left arm 11, the upper right arm 12, the lower left arm 13, and the lower right arm 14. Each rotor is the same size and is driven by a brushless DC motor of the same specification. The first rotor 1, the third rotor 3, the fifth rotor 5, and the seventh rotor 7 rotate clockwise, and the second rotor 2, the fourth rotor 4, the sixth rotor 6, and the eighth rotor 8 rotate counterclockwise. The left nozzle fixing plate 15 and the right nozzle fixing plate 16 are installed directly below the rotor, and each has three nozzles 17. The pesticide in the pesticide box 21 is pressurized by the water pump 23, sprayed out by the six pesticide nozzles 17 through the infusion pipe 22, and accelerated by the downwash airflow of the eight rotors to spray to the farmland to achieve plant protection operations.

[0045] like Figures 2-3 As shown, the upper mounting plate 26 and the lower mounting plate 27 are used to clamp and fix the left upper arm 11 and the right upper arm 12, and the left upper arm 11 and the right upper arm 12 have the same shape and are symmetrical. The upper body mounting plate 28 and the lower body mounting plate 29 are used to tighten and fix the left lower arm 13 and the right lower arm 14, and the left lower arm 13 and the right lower arm 14 have the same shape and are symmetrical. The upper arm (the left upper arm 11 and the right upper arm 12) and the lower arm (the left lower arm 13 and the right lower arm 14) are connected by four arm connecting rods 18 and four mounting plate fixing rods 25. The left arm reinforcement plate 9 and the right arm reinforcement plate 10 are respectively installed at the left and right ends of the arm, which play the role of connecting the upper arm and the lower arm, and at the same time prevent the upper arm from breaking due to excessive bending moment.

[0046] like Figures 3-4 As shown, the upper mounting plate 26 is used to place the avionics equipment of the UAV (such as flight control computers, navigation equipment, data transmission radios, etc.). At the same time, the upper body mounting plate 28 can be used to place batteries to provide power for the brushless DC motor, nozzles and avionics equipment of the rotor. The landing gear 24 is fixed to the bottom surface of the lower body mounting plate. The landing gear 24 is equipped with a pesticide box 21 and a nozzle fixing plate (left nozzle fixing plate 15 and right nozzle fixing plate 16). The nozzle fixing plate is equipped with a total of six nozzles for spraying pesticides. The nozzle fixing plate reinforcement (left nozzle fixing plate reinforcement 19, right nozzle fixing plate reinforcement 20) connects the landing gear and the nozzle fixing plate, which can reduce the degree of bending of the nozzle fixing plate due to gravity.

[0047] A double-layer arm horizontal multi-rotor plant protection drone, whose special double-layer arm horizontal distribution can reduce the airflow interference between each pair of rotors, and the horizontal and double-layer design can increase the number of rotor installations, so the effective spraying width of pesticides becomes longer and the load capacity is increased. Compared with traditional multi-rotor plant protection drones, the double-layer arm horizontal multi-rotor plant protection drone of the present invention has better aerodynamic performance and plant protection efficiency.

[0048] A double-layer arm horizontal multi-rotor plant protection UAV, the flight control method of which is as follows (the eight rotors have the same initial rotation speed, the first rotor 1, the third rotor 3, the fifth rotor 5, and the seventh rotor 7 rotate clockwise, and the second rotor 2, the fourth rotor 4, the sixth rotor 6, and the eighth rotor 8 rotate counterclockwise):

[0049] 1) Forward flight: The second rotor 2 and the fifth rotor 5 increase their rotation speed (increase the pulling force), and the first rotor 1 and the sixth rotor 6 reduce their rotation speed (decrease the pulling force). At this time, the UAV generates a nose-down moment. The UAV flies with its head down, and the rotor generates a forward component force to overcome the forward resistance of the UAV and realize forward flight;

[0050] 2) Backward flight: The second rotor 2 and the fifth rotor 5 reduce their rotation speed (thrust decreases), and the first rotor 1 and the sixth rotor 6 increase their rotation speed (thrust increases). At this time, the UAV generates a nose-up moment, the UAV flies upward, and the rotor generates a backward component force to overcome the rearward resistance of the UAV and realize backward flight;

[0051] 3) Left-side flight: The first rotor 1 and the second rotor 2 reduce their rotation speed (thrust decreases), and the fifth rotor 5 and the sixth rotor 6 increase their rotation speed (thrust increases). At this time, the drone generates a counterclockwise rolling moment, the drone rolls counterclockwise, and the rotor generates a left component force to overcome the left resistance of the drone and achieve left-side flight;

[0052] 4) Right-side flight: The first rotor 1 and the second rotor 2 increase their rotation speed (increase the pulling force), and the fifth rotor 5 and the sixth rotor 6 reduce their rotation speed (reduce the pulling force). At this time, the drone generates a clockwise rolling moment, the drone rolls clockwise, and the rotor generates a right component force to overcome the right resistance of the drone and achieve left-side flight;

[0053] 5) Clockwise yaw: The speeds of the second rotor 2, the fourth rotor 4, the sixth rotor 6, and the eighth rotor 8 increase (the clockwise anti-torque increases), the anti-torque balance of the drone is broken, and the drone generates a clockwise torque, resulting in clockwise yaw motion;

[0054] 6) Counterclockwise yaw: The rotation speeds of the first rotor 1, the third rotor 3, the fifth rotor 5, and the seventh rotor 7 increase (the counterclockwise anti-torque increases), the anti-torque balance of the UAV is broken, and the UAV generates a counterclockwise torque, resulting in a counterclockwise yaw motion;

[0055] 7) Ascent: The eight rotors simultaneously increase the rotor speed (increase the pulling force), the total pulling force of the rotors increases, overcoming the gravity and resistance of the drone, and the drone flies upwards;

[0056] 8) Descending: The eight rotors reduce the rotor speed at the same time (thrust decreases), the total rotor thrust decreases, and if it is less than the gravity of the drone, it will fly downward.

[0057] The main parameters of the double-layer arm transverse multi-rotor plant protection drone of the present invention are shown in Table 1. Through experiments and theoretical calculations, it is measured that the transverse multi-rotor plant protection drone with the same size of double-layer arms in the hovering state is 14% higher than the traditional multi-rotor plant protection drone, while the required power is reduced by 7%, and the effective spray width of pesticides is increased by 50%, indicating that the aerodynamic performance and plant protection operation efficiency of the double-layer arm transverse multi-rotor plant protection drone are better than those of the traditional multi-rotor plant protection drone.

[0058] Table 1 Parameters of a double-layer arm horizontal multi-rotor agricultural drone

[0059]

[0060] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those generally understood by those skilled in the art in the art to which the present invention belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless defined as herein.

[0061] The above description is only a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements without departing from the principle of the present invention, and these improvements should also be regarded as within the protection scope of the present invention.

Claims

1. A double-layer arm horizontal multi-rotor plant protection drone, characterized in that: The horizontal multi-rotor agricultural drone comprises upper and lower arms, and eight rotors, wherein the eight rotors are distributed on the upper and lower arms in a horizontal arrangement; the upper and lower arms comprise a left upper arm (11), a right upper arm (12), a left lower arm (13), and a right lower arm (14); the eight rotors comprise a first rotor (1), a second rotor (2), a third rotor (3), a fourth rotor (4), a fifth rotor (5), a sixth rotor (6), a seventh rotor (7), and an eighth rotor (8); the first rotor (1), the second rotor (2), the third rotor (3) , a fourth rotor (4), a fifth rotor (5), a sixth rotor (6), a seventh rotor (7), and an eighth rotor (8), a total of eight rotors are arranged in a horizontal row on the upper left arm (11), the upper right arm (12), the lower left arm (13), and the lower right arm (14); each rotor is of the same size and driven by a brushless DC motor of the same specification; the first rotor (1), the third rotor (3), the fifth rotor (5), and the seventh rotor (7) rotate clockwise; the second rotor (2), the fourth rotor (4), the sixth rotor (6), and the eighth rotor (8) rotate counterclockwise; The left nozzle fixing plate (15) and the right nozzle fixing plate (16) are installed directly below the rotors, and each has three nozzles (17). The pesticide in the pesticide box (21) is pressurized by a water pump (23), sprayed out by six pesticide nozzles (17) through a liquid delivery pipe (22), and accelerated by the downwash airflow of the eight rotors to spray onto the farmland, thereby achieving plant protection operations.

2. The double-layer arm horizontal multi-rotor plant protection UAV according to claim 1, characterized in that: The rotors mounted on the upper and lower arms are respectively clamped and fixed by an upper mounting plate (26) and a lower mounting plate (27) to the left upper arm (11) and the right upper arm (12), and the left upper arm (11) and the right upper arm (12) are of the same shape and symmetrical; the left lower arm (13) and the right lower arm (14) are clamped and fixed by an upper body mounting plate (28) and a lower body mounting plate (29), and the left lower arm (13) and the right lower arm (14) are of the same shape and symmetrical.

3. The double-layer arm horizontal multi-rotor plant protection UAV according to claim 2, characterized in that: The upper mounting plate (26) is used to place the avionics equipment of the UAV; at the same time, the upper fuselage mounting plate (28) is used to place batteries to provide power for the brushless DC motor of the rotor, the nozzle (17) and the avionics equipment.

4. The double-layer arm horizontal multi-rotor plant protection UAV according to claim 2, characterized in that: The landing gear (24) is fixed to the bottom surface of the lower body mounting plate (29). A pesticide box (21) and a nozzle fixing plate are mounted on the landing gear (24). The nozzle fixing plate is divided into a left nozzle fixing plate (15) and a right nozzle fixing plate (16). Three nozzles (17) are respectively mounted on the left nozzle fixing plate for spraying pesticides. The nozzle fixing plate reinforcement (the left nozzle fixing plate reinforcement (19) and the right nozzle fixing plate reinforcement (20)) connect the landing gear (24) and the nozzle fixing plate, so as to reduce the degree of bending of the nozzle fixing plate due to gravity.

5. The double-layer arm horizontal multi-rotor plant protection UAV according to claim 1, characterized in that: The upper machine arm (left upper machine arm (11) and right upper machine arm (12)) and the lower machine arm (left lower machine arm (13) and right lower machine arm (14)) are connected by four machine arm connecting rods (18) and four mounting plate fixing rods (25). The left machine arm reinforcement plate (9) and the right machine arm reinforcement plate (10) are respectively installed at the left and right ends of the machine arm to connect the upper machine arm and the lower machine arm, and at the same time prevent the upper machine arm from being broken due to excessive bending moment.

6. A double-layer arm horizontal multi-rotor plant protection UAV according to any one of claims 1 to 5, characterized in that: The flight control method of the horizontal multi-rotor plant protection UAV is as follows: 1) Forward flight: the second rotor (2) and the fifth rotor (5) increase their rotation speed (increase the pulling force), while the first rotor (1) and the sixth rotor (6) decrease their rotation speed (decrease the pulling force). At this time, the drone generates a nose-down moment. The drone flies with its head down, and the rotor generates a forward component force to overcome the forward resistance of the drone, thereby achieving forward flight. 2) Backward flight: the second rotor (2) and the fifth rotor (5) reduce their rotation speed (thrust decreases), while the first rotor (1) and the sixth rotor (6) increase their rotation speed (thrust increases). At this time, the drone generates a nose-up moment, the drone flies upward, and the rotor generates a backward component force to overcome the rearward resistance of the drone, thereby achieving backward flight; 3) Left-side flight: the first rotor (1) and the second rotor (2) reduce their rotation speed (thrust decreases), while the fifth rotor (5) and the sixth rotor (6) increase their rotation speed (thrust increases). At this time, the drone generates a counterclockwise rolling moment, the drone rolls counterclockwise, and the rotor generates a left component force to overcome the leftward resistance of the drone, thereby achieving left-side flight; 4) Right-side flight: the first rotor (1) and the second rotor (2) increase their rotation speed (increase the pulling force), while the fifth rotor (5) and the sixth rotor (6) decrease their rotation speed (decrease the pulling force). At this time, the drone generates a clockwise rolling moment, the drone rolls clockwise, and the rotor generates a right component force to overcome the rightward resistance of the drone, thus achieving left-side flight; 5) Clockwise yaw: the rotation speeds of the second rotor (2), the fourth rotor (4), the sixth rotor (6), and the eighth rotor (8) increase (the clockwise anti-torque increases), the anti-torque balance of the drone is broken, and the drone generates a clockwise torque, resulting in a clockwise yaw motion; 6) Counterclockwise yaw: the rotation speeds of the first rotor (1), the third rotor (3), the fifth rotor (5), and the seventh rotor (7) increase (the counterclockwise anti-torque increases), the anti-torque balance of the UAV is broken, and the UAV generates a counterclockwise torque, resulting in a counterclockwise yaw motion; 7) Ascent: The eight rotors simultaneously increase the rotor speed (increase the pulling force), the total pulling force of the rotors increases, overcoming the gravity and resistance of the drone, and the drone flies upwards; 8) Descending: The eight rotors reduce the rotor speed at the same time (thrust decreases), the total rotor thrust decreases, and if it is less than the gravity of the drone, it will fly downward.

7. The double-layer arm horizontal multi-rotor plant protection UAV according to claim 6, characterized in that: The eight rotors of the horizontal multi-rotor agricultural drone have the same initial rotation speed; the first rotor (1), the third rotor (3), the fifth rotor (5), and the seventh rotor (7) rotate clockwise; and the second rotor (2), the fourth rotor (4), the sixth rotor (6), and the eighth rotor (8) rotate counterclockwise.

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