Water quality monitoring unmanned aerial vehicle

Abstract

The invention relates to the technical field of unmanned aerial vehicle design, and discloses a water quality monitoring unmanned aerial vehicle which comprises a fuselage, wings, a buoy and a vertical fin, the wings are fixed to the two sides of the fuselage, the mounting angle between the wings and the fuselage is 4-6 degrees, each wing comprises an inner wing and an outer wing which are sequentially connected from inside to outside, and the rear edge of each outer wing is connected with an aileron; the wings and the ailerons form inverted triangular combined wings, inner wings face upwards, outer wings face downwards, and gull-wing layout is formed. The buoy is connected to the outer ends of the outer wings, winglet or end plates are arranged at the top of the buoy, the two vertical tails are symmetrically and fixedly connected to the tail end of the fuselage, the tops of the vertical tails are connected with the horizontal tails, and the rear edges of the horizontal tails are connected with the elevators. According to the water quality monitoring unmanned aerial vehicle, the gull-wing layout is formed through the design that the inner wings of the wings are upwards reversed and the outer wings of the wings are downwards reversed, the combination design that the inner wings are upwards reversed and the outer wings are downwards reversed is combined, and local airflow distribution is accurately adjusted by adjusting and controlling the relative distances between different parts of the wings and the ground, so that the advantage of the ground effect is fully played.

Description

Technical Field

[0001] The invention relates to the technical field of unmanned aerial vehicle design, and in particular to a water quality monitoring unmanned aerial vehicle. Background Art

[0002] As my country's natural environment improves and transportation capacity continues to increase, problems such as offshore patrols and inland river (lake) water quality monitoring need to be solved urgently. The traditional water quality testing method requires manual driving of boats to the middle of the lake for sampling, which not only requires a lot of manpower and material resources, but also takes a long time and has low work efficiency. The use of drones for water quality monitoring and sampling can make up for these shortcomings.

[0003] Compared with traditional manual inspections, drone water inspections can not only overcome the limitations of "wide watershed, trivial patches, complex terrain" and other factors, but also fully grasp the basic situation of the water area. However, the currently widely used multi-rotor drones perform poorly in terms of cruising efficiency and endurance, and rarely consider waterproofness. Therefore, there is a demand for a drone with long-term endurance near the water surface. When flying near the water surface, drones can effectively improve the quality of monitoring visual information, while at the same time being able to take advantage of the ground effect, increase the lift-to-drag ratio, and improve cruising efficiency and time. Therefore, the use of small ground-effect drones for water quality monitoring can achieve high-quality and high-efficiency monitoring, and the ground effect provides a theoretical basis for long-term flight near the water surface.

[0004] A ground effect drone is a large-scale transport vehicle that combines the characteristics of a drone and a ship. It can fly using the ground effect and has higher aerodynamic efficiency than conventional aircraft. A ground effect drone reduces its flight altitude, compressing the air flow between the wing and the ground, thereby generating stronger lift. Although there are drones that use the ground effect principle, the wing layouts of existing ground effect drones include straight wings with a large aspect ratio, tandem wings or biplane layouts, and compound wing layouts (front wing + main wing), but there are still some problems: such as insufficient lateral stability and difficulty in transitioning to the ground effect zone. Therefore, how to further improve flight stability and aerodynamic efficiency has not been fully studied. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a water quality monitoring UAV, which makes full use of the ground effect and improves the cruising efficiency.

[0006] The present invention provides a water quality monitoring unmanned aerial vehicle, comprising: a fuselage, wings, pontoons and a vertical tail. The wings are fixed on both sides of the fuselage, and the installation angle between the wings and the fuselage is 4°-6°. The wings include an inner wing and an outer wing connected in sequence from inside to outside. Ailerons are connected to the trailing edge of the outer wing. The wings and the ailerons form an inverted triangle combined wing. The inner wing is dihedral, and the outer wing is anhedral, forming a gull-wing layout. The pontoons are connected to the outer ends of the outer wings. Winglets or end plates are provided on the tops of the pontoons. Two vertical tails are symmetrically fixedly connected to the tail end of the fuselage, and a horizontal tail is connected to the top of the vertical tail. An elevator is connected to the trailing edge of the horizontal tail.

[0007] Optionally, the inner wing is a rectangular wing, the outer wing is a trapezoidal wing, the dihedral angle of the inner wing is 5°, the anhedral angle of the outer wing is 9°, and the aspect ratio of the inner wing to the outer wing is 3:7.

[0008] Optionally, the airfoil of the wing is an inverted S-shaped airfoil, the maximum camber of the wing is 8.89%, and the position of the maximum camber of the wing is at 34.2% of the chord length.

[0009] Optionally, the leading edge of the wing is straight, the trailing edge of the wing is forward-swept, and the aspect ratio of the wing is 2-4.

[0010] Optionally, the wingspan of the wing is 1.2 meters, the aspect ratio is 3.75, the taper ratio is 9.60, the chord length at the wing root is 0.48 meters, the mean aerodynamic chord length is 0.3826 meters, the area of the wing is 0.3845 square meters, and the installation angle is 4°.

[0011] Optionally, the bottom of the fuselage is in the shape of an inclined planing hull.

[0012] Optionally, the vertical tail is of NACA 0012 airfoil, the wingspan of the vertical tail is 0.2 meters, the chord length at the wing root of the vertical tail is 0.15 meters, the leading-edge sweep angle of the vertical tail is 42°, and the trailing-edge sweep angle is 36.87°.

[0013] Optionally, the horizontal tail is of NACA 0012 airfoil, the wingspan of the horizontal tail is 0.6-0.75 meters, the aspect ratio of the horizontal tail is 3-5, the tail volume coefficient of the horizontal tail is 0.51, and the installation angle is 3°.

[0014] Optionally, two grooves are provided at the trailing edge of the horizontal tail. The two grooves are symmetrically arranged, and an elevator is embedded in each groove. The deflection angle range of the elevator is -30°-30°.

[0015] Optionally, the total wingspan of the two elevators accounts for 70% of the wingspan of the horizontal tail, and the chord length of the elevator accounts for 30% of the chord length of the horizontal tail.

[0016] The technical solutions provided by the embodiments of the present invention have the following advantages compared with the prior art: A water quality monitoring UAV provided by an embodiment of the present invention can utilize the high lift-to-drag ratio generated by a ground effect UAV at a low flight altitude to achieve long-term stable flight. A gull-wing layout is formed by the design of the inner wing upturned and the outer wing downturned. The combined design of the inner wing upturned and the outer wing downturned is combined with the relative distance between different parts of the wing and the ground to accurately adjust the local airflow distribution, thereby giving full play to the advantages of the ground effect. The downturn of the outer wing makes the wing tip part closer to the ground at a low flight altitude, thereby enhancing the static pressure field effect of the area, reducing the induced drag and increasing the local lift coefficient. The outer wing can make full use of the airflow reflected from the ground at a low flight altitude to improve the cruising efficiency, while the upturn of the inner wing makes the wing root part appropriately away from the ground to prevent excessive concentration of the ground effect. The flow separation or pressure distribution fluctuates violently, thereby maintaining the balance of lift and drag distribution, reducing pitch moment fluctuations, and ensuring flight stability. The two work together to enable the UAV to obtain a balanced lift distribution and low aerodynamic drag in the ground effect area, while effectively suppressing the nonlinear aerodynamic effect caused by altitude changes, ensuring stability and efficient cruising during cross-altitude flight, and enabling a smooth transition in the ground effect area. The aileron is set at the trailing edge of the outer wing. By adjusting the aileron deflection angle, the rolling moment can be accurately controlled, thereby improving the lateral control ability of the UAV. Under the action of the ground effect, the lift generated by the wing changes more sensitively, and the role of the aileron is particularly critical, which enables the UAV to maintain a stable lateral balance when subjected to local airflow disturbances. By setting the buoy at the outer end of the outer wing and setting a winglet or end plate on the top of the buoy, the wingtip vortex can be reduced and the lateral stability can be improved. The vertical tail can maintain the longitudinal stability of the UAV. The horizontal tail and the elevator work together to adjust the pitch angle of the UAV to ensure the longitudinal static stability of the UAV, thereby improving flight stability. Finally, by adjusting the wing installation angle to 4°~6° and the balancing angles of the horizontal tail and elevator, the balanced angle of attack is guaranteed to be relatively stable at different flight altitudes, the pitch stability in the ground effect area is enhanced, and at the same time, instability at large angle of attack when leaving the ground effect area is avoided.

[0017] Compared with existing water quality monitoring tools, the water quality monitoring drone provided by the present invention has stronger stability and lower energy consumption, can more efficiently meet the needs of complex water area monitoring, and is particularly suitable for long-term and wide-range water quality monitoring tasks. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of the overall structure of a water quality monitoring drone provided by an embodiment of the present invention; Figure 2 A top view of a water quality monitoring drone provided by an embodiment of the present invention; Figure 3 A front view of a water quality monitoring drone provided by an embodiment of the present invention; Figure 4 The right view of a water quality monitoring unmanned aerial vehicle provided by an embodiment of the present invention; Figure 5 The structural schematic diagram of the outer wing and aileron provided by an embodiment of the present invention; Figure 6 The structural schematic diagram of the vertical tail and rudder provided by an embodiment of the present invention; Figure 7 The pressure coefficient contour map of the airfoil under ground effect in an embodiment of the present invention.

[0019] Explanation of reference numerals: 1, wing; 2, aileron; 3, winglet; 4, float; 5, fuselage; 6, vertical tail; 7, rudder; 8, horizontal tail; 9, elevator; 10, motor; 11, motor box; 12, propeller; 13, outer wing; 14, inner wing; 15, leading edge of wing; 16, trailing edge of wing. Detailed implementation manners

[0020] The following combines the drawings to describe in detail a specific implementation manner of the present invention, but it should be understood that the protection scope of the present invention is not limited by the specific implementation manner.

[0021] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the technical solutions of the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention.

[0022] Although there are currently unmanned aerial vehicles using the ground effect principle, the wing layouts of existing ground effect unmanned aerial vehicles include high aspect ratio straight wings, tandem wings or bi-wing layouts, compound wing layouts (front wing + main wing), etc., but there are still some problems: such as insufficient lateral stability and difficult transition in the ground effect area. Therefore, how to further improve flight stability and aerodynamic efficiency has not been fully studied.

[0023] For this reason, an embodiment of the present invention provides a water quality monitoring unmanned aerial vehicle, which can make full use of the ground effect and improve the cruise efficiency.

[0024] At least one embodiment of the present invention provides a water quality monitoring unmanned aerial vehicle, comprising: a fuselage, wings, pontoons and a vertical tail. The wings are fixed on both sides of the fuselage, and the installation angle between the wings and the fuselage is 4° - 6°. The wings include an inner wing and an outer wing connected in sequence from inside to outside. Ailerons 2 are connected to the trailing edge of the outer wing. The wings and the ailerons 2 form an inverted triangular combined wing. The inner wing is dihedral and the outer wing is anhedral, forming a gull-wing layout. The pontoons are connected to the outer ends of the outer wings, and winglets or end plates are provided on the tops of the pontoons. Two vertical tails are symmetrically fixed to the tail end of the fuselage, and a horizontal tail is connected to the top of the vertical tail. An elevator is connected to the trailing edge of the horizontal tail.

[0025] In the water quality monitoring unmanned aerial vehicle provided by the above embodiment of the present invention, by making the inner wing of the wing dihedral and the outer wing anhedral, a gull-wing layout is formed, which makes more full use of the ground effect and improves the cruise efficiency.

[0026] The present invention will be described below through several specific embodiments. To keep the description below of the embodiments of the present invention clear and concise, detailed descriptions of known functions and known components may be omitted. When any component of the embodiments of the present invention appears in more than one drawing, the component may be denoted by the same reference numeral in each drawing.

[0027] Refer to Figure 1 、 Figure 2 、 Figure 3 、 Figure 5 and Figure 7 , Figure 1 is a schematic diagram of the overall structure of a water quality monitoring unmanned aerial vehicle provided by an embodiment of the present invention, Figure 2 is a top view of a water quality monitoring unmanned aerial vehicle provided by an embodiment of the present invention, Figure 3 is a front view of a water quality monitoring unmanned aerial vehicle provided by an embodiment of the present invention, Figure 5 are the outer wing and ailerons in an embodiment of the present invention, Figure 7 is the pressure coefficient contour map of the airfoil under the ground effect in an embodiment of the present invention, as Figure 1 、 Figure 2 、 Figure 3 、 Figure 5 and Figure 7As shown in the figure, an embodiment of the present invention provides a water quality monitoring unmanned aerial vehicle, comprising: a fuselage 5, wings 1, pontoons 4 and a vertical tail 6. The fuselage 5 is made of streamlined composite material and has a cabin inside for placing a flight control system, a battery and other necessary electronic devices. The wings 1 are fixed on both sides of the fuselage 5, and the installation angle between the wings 1 and the fuselage 5 is 4° - 6°. Thus, even when flying at a small angle of attack in an emergency, a relatively large local angle of attack can be maintained, increasing the ground effect, ensuring that the fuselage is horizontal and the wings maintain the optimal angle of attack during cruising, and reducing the induced drag. The wings 1 include an inner wing 14 and an outer wing 13 connected in sequence from inside to outside. Ailerons 2 are connected to the trailing edge of the outer wing 13. The span of the ailerons 2 is 0.3 m, and the deflection angle range is -30° to 30°. The area of the ailerons 2 accounts for 20% - 30% of the trailing edge of the outer wing 13, ensuring the maneuvering response speed during low-speed water area monitoring. The design of the ailerons 2 can provide sufficient lateral control moment, improving the maneuverability and response ability of the unmanned aerial vehicle. The wings 1 and the ailerons 2 form an inverted triangle combined wing. The inner wing 14 is dihedral and the outer wing 13 is anhedral, forming a gull-wing layout. The pontoons 4 are connected to the outer ends of the outer wings 13. Winglets 3 or end plates are provided on the tops of the pontoons 4. The pontoons 4 provide additional buoyancy when the unmanned aerial vehicle takes off, lands or floats on the water surface, helping to maintain lateral balance and prevent rollover, enabling the unmanned aerial vehicle to slide smoothly on the water surface, especially reducing bumps during the high-speed sliding stage. The winglets 3 or end plates are used to reduce wingtip vortices and improve lateral stability., two vertical tails 6 are symmetrically and fixedly connected to the tail end of the fuselage 5. The top of the vertical tail 6 is connected to the horizontal tail 8, and the trailing edge of the horizontal tail 8 is connected to the elevator 9. The power system of the UAV is symmetrically distributed on both sides of the fuselage 5 and is located at the front end of the wing 1. The power device includes components such as the motor 10, the propeller 12, the electronic speed controller, and the motor box 11. The motor 10 has a stator outer diameter of 22 mm, a stator thickness of 16 mm, a rotor diameter of 27.7 mm, a motor 10 length of 34 mm, a rotor pole number of 14, a KV value of 1400, a weight of 71 g, an no-load current of 1.2 A, a motor 10 resistance of 32.2 mΩ, a maximum continuous current of 50 A (30 s), a maximum continuous power of 740 W, and is paired with a three-blade propeller of model 8040. The selected propeller 12 model is 8040, the number of blades is 3, made of PC material, the pitch is 4 inches, the propeller disk diameter is 204 mm, the center thickness is 7.5 mm, the inner diameter of the center hole is 5 mm, the maximum blade width is 20 mm, and the weight is 10.51 g. The propellers 12 on both sides are counter-rotating propellers with opposite rotation directions, ensuring the high-efficiency flight of the UAV at low flight altitudes. The selected electronic speed controller has a continuous current of 50 A, a weight of 16.5 g, and dimensions of 33×16×10 mm, which can ensure stable power supply for the UAV during long-term flight. The wing 1 is in the backward slipstream of the propeller 12, which is beneficial to increasing lift. The gull-wing layout can reduce the interference of wingtip vortices on the water surface, ensuring accurate data collection when the sensor (such as a multispectral camera, pH probe) is 1 to 3 meters above the water surface. Each motor 10 is fixed to the motor 10 box through four groups of bolt fasteners. The motor 10 box is spliced by 2-mm basswood laminates through a mortise-and-tenon structure. The motor 10 box is then connected to the fuselage 5 through a carbon fiber tube with an outer diameter of 14 mm. There is an electrical wiring port behind the interface between the fuselage 5 and the carbon fiber tube. The power device provides continuous and stable thrust through the combination of a high-efficiency motor and a propeller, ensuring that the UAV can overcome the wind resistance and aerodynamic disturbances during low-altitude flight. The bilateral counter-rotating propeller design not only balances the thrust but also reduces the yaw risk caused by thrust imbalance.

[0028] A water quality monitoring UAV provided by an embodiment of the present invention can utilize the high lift-to-drag ratio generated by a ground effect UAV at a low flight altitude to achieve long-term stable flight. A gull-wing layout is formed by the design of the inner wing upturned and the outer wing downturned. The combined design of the inner wing upturned and the outer wing downturned is combined with the relative distance between different parts of the wing and the ground to accurately adjust the local airflow distribution, thereby giving full play to the advantages of the ground effect. The downturn of the outer wing makes the wing tip part closer to the ground at a low flight altitude, thereby enhancing the static pressure field effect of the area, reducing the induced drag and increasing the local lift coefficient. The outer wing can make full use of the airflow reflected from the ground at a low flight altitude to improve the cruising efficiency, while the upturn of the inner wing makes the wing root part appropriately away from the ground to prevent excessive concentration of the ground effect. The flow separation or pressure distribution fluctuates violently, thereby maintaining the balance of lift and drag distribution, reducing pitch moment fluctuations, and ensuring flight stability. The two work together to enable the UAV to obtain a balanced lift distribution and low aerodynamic drag in the ground effect area, while effectively suppressing the nonlinear aerodynamic effect caused by altitude changes, ensuring stability and efficient cruising during cross-altitude flight, and enabling a smooth transition in the ground effect area. The aileron is set at the trailing edge of the outer wing. By adjusting the aileron deflection angle, the rolling moment can be accurately controlled, thereby improving the lateral control ability of the UAV. Under the action of the ground effect, the lift generated by the wing changes more sensitively, and the role of the aileron is particularly critical, which enables the UAV to maintain a stable lateral balance when subjected to local airflow disturbances. By setting the buoy at the outer end of the outer wing and setting a winglet or end plate on the top of the buoy, the wingtip vortex can be reduced and the lateral stability can be improved. The vertical tail can maintain the longitudinal stability of the UAV. The horizontal tail and the elevator work together to adjust the pitch angle of the UAV to ensure the longitudinal static stability of the UAV, thereby improving flight stability. Finally, by adjusting the wing installation angle to 4°~6° and the balancing angles of the horizontal tail and elevator, the balanced angle of attack is guaranteed to be relatively stable at different flight altitudes, the pitch stability in the ground effect area is enhanced, and at the same time, instability at large angle of attack when leaving the ground effect area is avoided.

[0029] Compared with existing water quality monitoring tools, the water quality monitoring drone provided by the present invention has stronger stability and lower energy consumption, can more efficiently meet the needs of complex water area monitoring, and is particularly suitable for long-term and wide-range water quality monitoring tasks.

[0030] In this embodiment, the inner wing 14 is a rectangular wing, a strict rectangle, with the leading and trailing edges being completely parallel to the longitudinal axis of the fuselage 5. It has a constant aspect ratio (3.2). The equal chord length design makes the stress distribution at the wing root uniform, facilitating the bearing of the high bending moment load at the fuselage connection point. The rectangular wing has a relatively large induced drag at low speeds (<100 km / h). Eddy current generators can be installed at the wing root to delay the airflow separation and improve the performance at large angles of attack (the critical angle of attack increases by 5°). The outer wing 13 is a trapezoidal wing, a linearly tapered trapezoid. The trapezoidal structure reduces the weight at the wing tip and suppresses the risk of flutter (especially suitable for carrying external sensors). The leading-edge sweep design at the trailing edge forms an aerodynamic coupling with the aileron notch, enhancing the roll response rate. The trapezoidal wing reduces the wing tip vortex, making the lift distribution elliptical along the span, and improving the cruise efficiency by 12%. The dihedral angle of the inner wing 14 is 5°. A dihedral angle of 5° means that the wing surface of the inner wing 14 makes an angle of 5 degrees upward with the horizontal line. Such a design helps to improve the low-speed stability of the aircraft, increase lift, and reduce induced drag. During the takeoff and landing phases, a lower dihedral angle helps to provide greater lift to help the aircraft overcome gravity and achieve smooth takeoff and landing. The dihedral angle of the inner wing 14 may also affect the roll characteristics of the aircraft. A smaller dihedral angle helps to improve the roll stability of the aircraft. The anhedral angle of the outer wing 13 is 9°. An anhedral angle of 9° means that the wing surface of the outer wing 13 makes an angle of 9 degrees downward with the horizontal line. Such a design helps to reduce the drag of the aircraft and improve the efficiency during high-speed flight. During high-speed flight, a larger anhedral angle helps to reduce drag and improve the cruise speed and fuel economy of the aircraft. The anhedral angle of the outer wing 13 also affects the lateral stability of the UAV. A larger anhedral angle helps to improve the lateral stability of the aircraft. The span ratio of the inner wing 14 to the outer wing 13 is 3:7. The inner wing 14 accounts for 30% of the span, and the outer wing 13 accounts for 70% of the span. The transition zone notch is located at the junction of the inner wing 14 and the outer wing 13 (accounting for 5% of the span). The aileron 2 is hinged here. The rectangular inner wing bears 35% - 40% of the total lift, and the concentrated distribution ensures the stability of the fuselage.

[0031] By designing the inner wing 14 as a rectangular wing and the outer wing 13 as a trapezoidal wing, both the structural strength and the aerodynamic performance are ensured. The dihedral angle of the inner wing 14 is 5°, and the anhedral angle of the outer wing 13 is 9°. At these angles, the lift-to-drag ratio of the UAV in the cruise condition is relatively excellent. The span ratio of the inner wing 14 to the outer wing 13 is the golden ratio of 3:7, which is the optimal lift-to-drag ratio distribution verified by wind tunnel tests and is the best ratio obtained by comprehensively considering the structure and aerodynamic performance. When the aileron deflects, differential eddies are generated using the span ratio difference, and the roll moment is increased by 40%. This design achieves a perfect balance between stability and maneuverability through precise span distribution and is particularly suitable for environmental monitoring tasks that require long-time flight close to the water surface.

[0032] Specifically, the airfoil of the wing 1 is an inverted S-shaped airfoil. The maximum camber of the wing 1 is 8.89%, and the position of the maximum camber of the wing 1 is at 34.2% of the chord length.

[0033] The wing 1 in the present invention adopts an inverted S-shaped airfoil improved based on the NACA M27 airfoil, effectively suppressing the drastic fluctuation of the pitching moment, and enabling the wing to exhibit more stable aerodynamic characteristics in the low-altitude and ground effect regions. The setting of the winglets (end plates) further reduces the wingtip vortices, reduces the induced drag, and enhances the lateral stability.

[0034] In this embodiment, the airfoil of the wing 1 is an inverted S-shaped airfoil improved based on the NACA M27 airfoil. This airfoil provides a high lift coefficient at a low angle of attack, and reduces the pitching moment change through the smooth movement of the center of pressure. This design reduces the lift mutation between the ground effect region and the conventional flight region, enabling the UAV to smoothly transition between different flight altitudes, with small non-linear aerodynamic changes, and keeping the lift and drag changes of the UAV relatively stable at different flight altitudes. The maximum camber of this airfoil is 8.89% and is located at 34.2% of the chord length, effectively reducing the pitching moment fluctuation, thereby improving the aerodynamic stability of the UAV. By configuring the installation angle of the wing and the airfoil parameters of the wing, the airflow distribution under the ground effect is made more uniform, which can suppress the instability caused by airflow separation or local disturbances and improve the overall aerodynamic performance.

[0035] Optionally, the leading edge 15 of the wing 1 is straight, the trailing edge 16 of the wing 1 is swept forward, and the aspect ratio of the wing 1 is 2 - 4, which can simplify the manufacturing process, form an inverted triangle combined wing with the swept-forward trailing edge, and the design of moving the center of gravity backward enhances the pitching stability and is suitable for carrying a head sensor payload. The vortex generator can increase the lift coefficient in a turbulent environment (Cl_max increases by 15%). The trailing edge 16 of the wing 1 is swept forward, and the aspect ratio of the wing 1 is 2 - 4, so that this short and thick airfoil is suitable for low speeds (cruise speed 50 - 80 km / h).

[0036] Specifically, the span of the wing 1 is 1.2 meters, the aspect ratio is 3.75, the taper ratio is 9.60, the chord length at the wing root is 0.48 meters, the mean aerodynamic chord length is 0.3826 meters, the area of the wing 1 is 0.3845 square meters, and the installation angle is 4°.

[0037] In the water quality monitoring UAV provided by the embodiment of the present invention, the wingspan of the wing 1 is 1.2 meters, which is suitable for small UAVs (maximum takeoff weight ≤ 15 kg), suitable for monitoring narrow waters or urban river channels. The aspect ratio is 3.75, with a low aspect ratio design to enhance the low-speed anti-turbulence ability. The taper ratio is 9.60, with the characteristics of an extreme trapezoidal wing, reducing the induced drag but requiring prevention of wingtip stall. The chord length at the wing root is 0.48 meters, the mean aerodynamic chord length is 0.3826 meters, the area of the wing 1 is 0.3845 square meters, and the installation angle is 4°. The cruise angle of attack is matched: when the fuselage 5 is horizontal, the actual angle of attack of the wing = 4°. When encountering a downdraft suddenly, the effective angle of attack is automatically increased to maintain the altitude (without frequent pitch adjustment). The aileron 2 has a wingspan of 0.3 meters, and the deflection angle range is -30° to 30°. The design of the aileron 2 can provide sufficient lateral control moment, improving the maneuverability and response ability of the UAV, so as to improve the controllability and lateral stability of the UAV.

[0038] In the embodiment of the present invention, the bottom of the fuselage 5 is in the shape of an inclined planing bottom, and this bottom configuration can ensure that the UAV floats stably on the water surface and overcomes the nose-down moment caused by the water surface viscosity during takeoff and landing.

[0039] Reference Figure 4 , Figure 4 is the right view of a water quality monitoring UAV provided by the embodiment of the present invention. As Figure 4 shown, the vertical tail 6 is of the NACA 0012 airfoil type. The wingspan of the vertical tail 6 is 0.2 meters, the chord length at the wing root of the vertical tail 6 is 0.15 meters, the leading edge sweep angle of the vertical tail 6 is 42°, and the trailing edge sweep angle is 36.87°.

[0040] For a ground effect UAV, the area or tail moment arm of the vertical tail 6 is generally relatively large. Considering the aerodynamic effect and the performance of the control system comprehensively, the parameters of the vertical tail 6 are designed. The vertical tail 6 can adopt the NACA 0012 airfoil type or other symmetric airfoil types. The ratio of the maximum thickness to the chord length is generally between 0.08 and 0.12. The wingspan is 0.2 meters, the aspect ratio is 2.96, the chord length at the wing root is 0.15 meters, the leading edge sweep angle is 42°, and the trailing edge sweep angle is 36.87°. The design of the vertical tail 6 is used to enhance the longitudinal stability of the UAV and reduce the sideslip phenomenon during flight. The vertical tail adopts the NACA 0012 airfoil type, combined with a relatively large sweep angle design, which not only enhances the longitudinal static stability of the UAV but also reduces the sideslip effect. The rudder is located at the trailing edge of the vertical tail. Through appropriate deflection, the course adjustment is realized, ensuring that the UAV can fly precisely along the predetermined route during low-altitude cruise.

[0041] Reference Figure 6 , Figure 6 is the structural schematic diagram of the vertical tail and the rudder provided by the embodiment of the present invention. As Figure 6As shown, the horizontal tail 8 has an NACA 0012 airfoil. The span of the horizontal tail 8 is 0.6 m to 0.75 m. The aspect ratio of the horizontal tail 8 is 3 to 5. The tail volume coefficient of the horizontal tail 8 is 0.51, and the installation angle is 3°. The horizontal tail 8 and the elevator 9 work together to adjust the pitch angle of the UAV. The installation angle and size of the horizontal tail are carefully designed to meet the requirements of altitude and pitch static stability.

[0042] The horizontal tail 8 uses an NACA 0012 airfoil. The span of the horizontal tail 8 is 0.6 m to 0.75 m. The aspect ratio of the horizontal tail 8 is 3 to 5. A rudder 7 is provided at the trailing edge of each vertical tail 6. The span of the rudder 7 is 0.14 m, and the deflection angle range is -30° to 30°. The rudder 7 can rotate as the control surface of the vertical tail 6 and is used for lateral-directional control by rotation. The rudder 7 can rotate within the above range relative to the vertical tail 6, similar to left and right rotation, for realizing the heading control of the UAV and ensuring its precise cruising in a complex water environment.

[0043] In this embodiment, the span of the horizontal tail 8 is 0.68 m, the aspect ratio is 3.78, the taper ratio is 1, the tail volume coefficient of the horizontal tail 8 is 0.51, and the installation angle is 3°. The geometric parameters of the horizontal tail 8 comprehensively consider the longitudinal static stability and pitch static stability of the UAV, and optimize the response performance of the flight control system. The horizontal tail 8 in the embodiment of the present invention has a relatively large span and a relatively high position compared with a general fixed wing. The relatively large span is to provide sufficient longitudinal moment control ability within the ground effect region, and the relatively high position is to place the horizontal tail outside the ground effect region to prevent the horizontal tail from being interfered by the complex airflow within the ground effect region, thereby affecting the longitudinal moment.

[0044] Considering that the control surface with too large a span is prone to deformation, the embodiment of the present invention provides a water quality monitoring UAV. Two grooves are opened at the trailing edge of the horizontal tail 8. The two grooves are symmetrically arranged. Each of the two grooves is inlaid with an elevator 9. The deflection angle range of the elevator 9 is -30° to 30°, which is used to finely adjust the pitch attitude of the UAV. The horizontal tail 8 and the elevator 9 work together to adjust the pitch angle of the UAV to ensure the longitudinal static stability of the UAV.

[0045] Since in the embodiment of the present invention, the span of the horizontal tail 8 of the UAV is relatively large, if the elevator 9 is only arranged in one section, it is easy to cause relatively large deformation. Therefore, it is divided into two sections and arranged in a symmetric distribution structure. The inlaid structure of the elevator 9 is simple and reliable. The segmented symmetric design of the elevator helps to control the deformation of the control surface while realizing fine pitch control, ensuring that the UAV maintains a stable attitude within the ground effect region.

[0046] Specifically, the total span of the elevator 9 is 0.476 m. The total span of the two elevators 9 accounts for 70% of the span of the horizontal tail 8. The chord length of the elevator 9 accounts for 30% of the chord length of the horizontal tail 8. The spanwise relative positions are 10% - 45% and 55% - 90% respectively. The chord length of the elevator 9 is 0.054 m, accounting for 30% of the chord length of the horizontal tail 8, and the deflection angle is -30° to 30°.

[0047] 10% and 90% mean that the elevator 9 starts to be arranged at 10% positions on both the left and right sides of the horizontal tail 8. According to the elevator span accounting for 70% of the horizontal tail span, due to symmetric arrangement, so 10% + 35% = 45%, 90% - 35% = 55%. The elevator chord length accounting for 30% of the horizontal tail chord length is obtained based on the design and manufacturing experience of the UAV. In the embodiments of the present invention, the fuselage 5, the wing 1, the horizontal tail 8 and the vertical tail 6 are manufactured by the foam cutting method to ensure the light weight and strength of the UAV. After each component is cut, it is bonded with epoxy resin. The structural connections use materials such as carbon fiber tubes and aluminum alloy parts to enhance the bending strength and stability. The design of the control surface and the control system considers the control surface deflection angle and deformation problems, and uses high-precision servos and self-tapping screws for fixation to ensure reliable control response. The surface of the UAV is covered with fiberglass cloth and epoxy resin to enhance the durability and aerodynamic performance of the surface structure. All electrical circuits are arranged through the electrical hatches inside the fuselage, and the electrical system of the UAV is ensured to be stably connected.

[0048] The wing 1, the fuselage 5, the horizontal tail 8 and the vertical tail 6 are separately cut, and several process separation surfaces are divided for each part according to the actual situation. After cutting, they are bonded with epoxy resin. The specific process is as follows: The wing 1 is divided into two sections on the left and right, connected by two carbon fiber tubes, and a process separation surface is set on each side. The upper and lower parts of the wing 1 on both sides are separately cut and then bonded. Two carbon fiber tubes are placed inside the wing 1 to enhance the bending strength, and a laser rangefinder is installed in the middle of the lower side of the inner wing 14.

[0049] The fuselage 5 is divided into the bottom, the head and the wing-body connection part. The motor 10 is installed at the head of the fuselage 5. A carbon fiber tube penetrates through the head of the fuselage 5 and is connected to the motor box 11 and the motor 10 at both ends, and is fixed with glue and epoxy resin. Laminates are added for fixation at key points. The boat-shaped part on the lower surface of the fuselage 5 and the rest of the chamfered parts are all polished. The opening cover on the upper surface of the fuselage 5 is used to place electronic devices.

[0050] The vertical tail 6 is bonded to the fuselage 5, and the horizontal tail 8 is placed on the vertical tail 6. The end face of the wing tip of the vertical tail 6 is cut into the cross-sectional shape of the horizontal tail 8 for easy bonding. The fuselage 5 is grooved for wiring.

[0051] The fiberglass cloth is laid on the surface of the UAV, and the prepared epoxy glue is brushed on the fiberglass to make it adhere to the surface of the UAV through the action of the glue.

[0052] The position where the control surface is connected to the wing 1 is polished to the designed deflection angle. Grooves are cut at the wing 1 and the horizontal and vertical stabilizer 6. A control surface cabin is made of laminates and fixed to the wing 1 with self-tapping screws. Wooden strips are placed and bonded to the wing surface with foam glue. The servo and the wooden strips are fixed with self-tapping screws. The control horn is bonded to the control surface with epoxy resin. The control horn and the servo rocker arm are connected by a wire tie rod and a quick adjuster.

[0053] Compared with traditional water quality monitoring tools, the water quality monitoring UAV provided by the embodiments of the present invention makes more full use of the ground effect and improves the cruise efficiency. Compared with existing water quality monitoring tools, it has higher endurance, stronger stability, lower energy consumption and higher monitoring accuracy, and can more efficiently meet the needs of complex water area monitoring, especially suitable for long-term and wide-range water quality monitoring tasks. This design makes the lift and drag changes of the UAV at different flight altitudes remain relatively stable, and can effectively cope with the common non-linear aerodynamic changes of ground effect UAVs, ensuring that the UAV has good stability. Compared with traditional surface ships or multi-rotor UAVs, the UAV of the present invention can work in a wider range of water area environments, including conditions such as broad basins, fragmented patches, and complex terrains. This enables the UAV to cover a wider monitoring area, especially suitable for remote waters that are difficult to reach by traditional means.

[0054] The UAV of the present invention is configured with multiple control surface components such as ailerons, horizontal stabilizers, vertical stabilizers and rudders to ensure the longitudinal static stability and control response of the UAV. The ailerons are installed at the trailing edge of the wings, with an extension length of 0.3 m and adjustable deflection angles. The designs of the vertical stabilizer and the rudder combine aerodynamic effects and control system performance requirements. The vertical stabilizer uses the NACA 0012 airfoil, with an extension length of 0.2 m and an aspect ratio of 2.96, and works together with the horizontal stabilizer and the elevator to ensure the stability and maneuverability of the UAV.

[0055] The above are only several specific embodiments of the present invention. However, the embodiments of the present invention are not limited thereto, and any changes that can be thought of by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. A water quality monitoring drone, characterized in that: include: Fuselage (5); The wing (1) is fixed on both sides of the fuselage (5), the installation angle between the wing (1) and the fuselage (5) is 4° to 6°, the wing (1) comprises an inner wing (14) and an outer wing (13) connected in sequence from the inside to the outside, the trailing edge of the outer wing (13) is connected to an aileron (2), the wing (1) and the aileron (2) form an inverted triangle combined wing, the inner wing (14) is reversed upwards, and the outer wing (13) is reversed downwards, forming a gull-wing layout; A buoy (4) connected to the outer end of the outer wing (13), wherein a winglet (3) or an end plate is provided on the top of the buoy (4); Two vertical tails (6) are symmetrically fixed to the tail end of the fuselage (5); the top of the vertical tail (6) is connected to a horizontal tail (8); and the trailing edge of the horizontal tail (8) is connected to an elevator (9).

2. A water quality monitoring drone as claimed in claim 1, characterized in that: The inner wing (14) is a rectangular wing, the outer wing (13) is a trapezoidal wing, the upper inclination angle of the inner wing (14) is 5°, the lower inclination angle of the outer wing (13) is 9°, and the aspect ratio of the inner wing (14) to the outer wing (13) is 3:

7.

3. A water quality monitoring drone as claimed in claim 1, characterized in that: The airfoil of the wing (1) is an inverted S-shaped airfoil, the maximum camber of the wing (1) is 8.89%, and the position of the maximum camber of the wing (1) is located at 34.2% of the chord length.

4. A water quality monitoring drone as claimed in claim 1, characterized in that: The leading edge (15) of the wing (1) is straight, the trailing edge (16) of the wing (1) is swept forward, and the aspect ratio of the wing (1) is 2-4.

5. A water quality monitoring drone as claimed in claim 1, characterized in that: The wing (1) has a span of 1.2 meters, an aspect ratio of 3.75, a root-to-tip ratio of 9.60, a wing root chord length of 0.48 meters, an average aerodynamic chord length of 0.3826 meters, an area of ​​0.3845 square meters, and an installation angle of 4 degrees.

6. A water quality monitoring drone as claimed in claim 1, characterized in that: The bottom of the fuselage (5) is in the shape of an obliquely rising ship bottom.

7. A water quality monitoring drone according to any one of claims 1 to 6, characterized in that: The vertical tail (6) is a NACA0012 airfoil, the span of the vertical tail (6) is 0.2 meters, the root chord length of the vertical tail (6) is 0.15 meters, the leading edge sweep angle of the vertical tail (6) is 42 degrees, and the trailing edge sweep angle is 36.87 degrees.

8. A water quality monitoring drone according to any one of claims 1 to 6, characterized in that: The horizontal tail (8) is a NACA0012 airfoil, the span of the horizontal tail (8) is 0.6 m to 0.75 m, the aspect ratio of the horizontal tail (8) is 3 to 5, the tail capacity coefficient of the horizontal tail (8) is 0.51, and the installation angle is 3°.

9. A water quality monitoring drone as claimed in claim 8, characterized in that: The rear edge of the horizontal tail (8) is provided with two grooves, the two grooves are symmetrically arranged, each groove is inlaid with an elevator (9), and the deflection angle range of the elevator (9) is -30° to 30°.

10. A water quality monitoring drone as claimed in claim 9, characterized in that: The total length of the two elevators (9) accounts for 70% of the length of the horizontal tail (8), and the chord length of the elevators (9) accounts for 30% of the chord length of the horizontal tail (8).

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