A water-air amphibious vector drone and its cross-medium navigation control method

Abstract

The present invention is an amphibious vector drone that can fly underwater and in the air. It adopts a vector twin-rotor flying wing layout. The wing shell includes an upper wing shell and a lower wing shell, which are respectively arranged above and below the frame to form a complete aerodynamic shape. The frame is located in the middle position near the leading edge of the wing. A frame waterproof membrane is affixed to the side of the frame. A closed cavity is set between the frame waterproof membrane and the upper and lower wing shells for installing flight control hardware, electronic speed regulator, and battery. In the area outside the frame where the frame waterproof membrane is affixed, a hollow structure is formed between the upper and lower wing shells. The side and trailing edge of the wing are not sealed, allowing water to freely enter the hollow structure formed by the upper and lower wing shells. Through the special design of the wing structure and the combination of a water-air integrated vector power system, it can achieve drive and attitude control underwater and in the air, avoiding the structural redundancy caused by the combination of multiple sets of power propulsion equipment.

Description

Technical Field

[0001] The present invention relates to the field of unmanned aerial vehicles (UAVs), and in particular to a water-air amphibious vector UAV and a cross-medium navigation control method thereof. Background Art

[0002] With the advancement of aircraft and aerial vehicle technology, single-medium navigation unmanned vehicles are increasingly unable to meet diverse military and civilian needs. Amphibious, cross-medium drones (UAVs) possess cross-medium navigation capabilities, combining the high stealth of underwater unmanned vehicles with the high speed and maneuverability of aerial vehicles. This makes them highly valuable in a wide range of applications, including maritime reconnaissance, surveillance, communications relay, landing penetration, air defense, and anti-submarine warfare. Cross-medium drones can also exploit the blind spots of various detection equipment, achieving stealth operations in unconventional ways.

[0003] To achieve cross-domain navigation, existing amphibious drones are mostly equipped with multiple propulsion systems to operate in various media. Furthermore, to enable the vehicle to submerge underwater, they are also equipped with mechanical displacement mechanisms that control the vehicle's submergence by controlling the amount of displacement. Amphibious drones rely on their wings to generate lift and balance gravity during flight. These wings are generally large, resulting in increased drag during underwater navigation and limiting the drone's performance in aquatic environments. To address this issue, most current amphibious drones utilize a folding wing design. This design uses a folding mechanism to fold the wings during underwater navigation, reducing the projected area in the direction of travel and thus reducing drag. These mechanical structures increase the complexity of the drone, reduce its reliability, and impose varying degrees of limitations on its performance. Existing amphibious drones require varying degrees of structural modification to navigate different media, making cross-media navigation cumbersome and complex. These various issues significantly limit the development of amphibious drones. Therefore, designing an amphibious drone with a simple structure and high reliability has great practical value and application prospects.

[0004] Automatic control technology is key to enabling autonomous navigation for UAVs. Existing UAV controllers are primarily designed for aerial flight, limiting their application requirements. This makes it difficult to achieve unified control of amphibious drones in air, water, and during water-to-air transitions, resulting in low efficiency and poor flexibility. Therefore, it is necessary to design a control system and method tailored to the specific cross-domain navigation characteristics of amphibious drones. This approach would allow for effective control of amphibious drones in both water and air environments, while also enabling smooth transitions between water and air modes. Summary of the Invention

[0005] Technical issues to be solved:

[0006] The present invention aims to overcome the shortcomings of existing amphibious drones in terms of mechanical and control systems. It aims to design a novel amphibious vector drone and a control method for cross-medium navigation. This approach enables autonomous cross-medium navigation with a simple and reliable drone, resolving the structural redundancy and cumbersome cross-medium flight procedures of existing amphibious drones. The drone described in this invention eliminates the various additional mechanisms typically required for cross-domain navigation, nor does it require corresponding structural adjustments for cross-medium navigation, significantly improving the reliability of the amphibious drone.

[0007] The technical solutions adopted are as follows:

[0008] In order to achieve the above objectives, the UAV of the present invention adopts a vector twin-rotor flying wing layout, a special design of the wing structure, and combined with a water-air integrated vector power system, it can realize drive and attitude control underwater and in the air, avoiding the structural redundancy brought by matching multiple sets of power propulsion equipment; the hollow structure design of the wing makes it possible to achieve suspension of the UAV in the water without equipping a mechanical drainage device, further simplifying the complexity of the system; in view of the large underwater navigation resistance, a bionic appearance design is adopted, and the plane shape of the wing is designed to be streamlined, which can reduce the pressure difference resistance of the UAV when it is sailing underwater and enhance the UAV's underwater navigation ability. And according to the characteristics of the designed water-air amphibious vector UAV, cross-media flight control is achieved by adjusting the flight attitude in different media. The specific technical solution is as follows:

[0009] A water-air amphibious vector UAV adopts a vector twin-rotor flying wing layout, comprising a frame, a frame waterproof membrane, wings, a servo, a motor, a foldable propeller, flight control hardware, a battery and an electronic speed regulator. The servo realizes vector drive, and the wing comprises an upper wing shell and a lower wing shell, which are respectively arranged above and below the frame. The frame is located in the middle of the wing shell near the leading edge to form a complete aerodynamic shape. The frame waterproof membrane is attached to the side of the frame, and a closed cavity is formed between the frame waterproof membrane and the upper and lower wing shells for installing flight control hardware, an electronic speed regulator and a battery. In the area outside the closed cavity, a hollow structure is formed between the upper and lower wing shells, and the side end surface and the trailing edge of the wing are not closed, so that water can freely enter the hollow structure formed by the upper and lower wing shells.

[0010] Furthermore, the overall shape of the wing is a structure that is slightly thicker in the middle and slightly thinner on both sides. The middle part is the middle wing section, which is thicker and has sufficient internal space to install batteries, flight control hardware and electronic speed regulator; the left and right sides of the middle wing section are outer wing sections that use thinner low Rayleigh number and high lift-to-drag ratio airfoil designs; a smooth transition is used between the middle wing section and the outer wing section.

[0011] Furthermore, the plane of the wing is a planar structure imitating a manta ray, which is a pentagon with streamlined characteristics. The leading edge of the wing is swept back on both sides, with a sweep angle between 20 and 50 degrees; the trailing edge of the wing is swept forward, with a sweep angle between 20 and 40 degrees.

[0012] Furthermore, the rack is a frame structure, the shape of which is determined by the shape of the wing and needs to be designed jointly with the wing; an electronic equipment mounting seat is provided in the rack for installing flight control hardware, batteries and electronic speed regulator.

[0013] Furthermore, the servos are installed on the motor mounting brackets on both sides of the frame and distributed at both ends of the leading edge of the middle wing section of the wing. Through vector power, the floating and sinking movement of the drone underwater and the attitude control during flight in the air can be achieved.

[0014] The cross-media navigation control method of the water-air amphibious vector UAV includes: controlling the water-air amphibious vector UAV to transition from an air flight state to a water navigation state, and controlling the water-air amphibious vector UAV to transition from a water navigation state to an air flight state, wherein the water navigation state includes surface gliding and underwater diving.

[0015] Furthermore, when the water-air amphibious vector drone transitions from an aerial flight state to a water surface navigation state, the steering gear is used to adjust the attitude of the drone to keep it in a level flight state, and the flight altitude is continuously lowered so that the belly of the drone contacts the water surface first, thereby achieving the landing of the drone on the water surface; after landing on the water surface, the steering gear adjusts the deflection angle of the propeller to keep the axis of the propeller parallel to the water surface and keep the motor rotating, so that the drone can be driven to navigate on the water surface by relying on the pulling force generated by the propeller.

[0016] Furthermore, when the water-air amphibious vector drone transitions from an aerial flight state to an underwater stealth state, the servo adjusts the drone's flight attitude so that the drone flies in a rotor mode, that is, the drone's wing chord is nearly perpendicular to the water surface; the left and right propellers maintain the same rotational speed and gradually reduce the rotational speed to slowly lower the drone's flight altitude, and eventually the drone will contact the water surface; because the angle between the drone's wing chord and the water surface is large, the trailing edge of the wing will contact the water surface first;

[0017] After the trailing edge of the wing contacts the water, water enters the hollow structure between the upper and lower wing shells through the gap between the trailing edge, thereby increasing the overall density of the wing envelope. After the drone contacts the water surface, the propeller speed is slowly reduced until the drone is completely submerged in the water, completing the transition from air to water navigation.

[0018] After the drone is completely immersed in water, the servo is used to adjust the drone's attitude again so that the angle between the drone's wing chord and the water surface is maintained within a smaller range. The drone is then driven underwater using the same driving mode and control method as when the drone is flying in the air.

[0019] Furthermore, when the water-air amphibious vector drone transitions from surface navigation to air flight, the propeller axis is controlled by the servo to be in a vertical position and in the direction of the propeller pull, and then the speed of the motors on the left and right sides is increased synchronously. The drone leaves the water surface under the action of the propeller pull, then takes off vertically, and after reaching the specified height, it switches to a level flight state.

[0020] Furthermore, when the water-air amphibious vector drone transitions from underwater stealth to airborne flight, the propeller's pull is directed vertically upward by controlling the servo. Under the action of the propeller's pull, the drone continuously rises, and the drone's wing chord becomes nearly perpendicular to the water surface, with the nose pointing upward.

[0021] When the propeller leaves the water, the motor speed is reduced, causing the drone to slowly leave the water. Under the action of gravity, the water flows out of the hollow structure of the drone through the gaps between the side end surface and the trailing edge of the wing.

[0022] When the trailing edge of the drone leaves the water, it takes off using a rotor takeoff method, thus completing the transition of the drone from underwater navigation to air flight mode.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The integrated structure and function design results in a simple and reliable amphibious drone.

[0025] 2. The use of binary vector power, located on the left and right sides of the leading edge of the middle wing section, enables the UAV to be controlled underwater and in the air, avoiding the redundant design of multiple power sets of traditional amphibious UAVs and increasing the UAV's payload capacity. At the same time, the use of vector power eliminates the need for traditional rudders, improving the UAV's aerodynamic efficiency.

[0026] 3. Realize the integrated control of water-air amphibious cross-medium UAV; by controlling the landing posture of the UAV, the UAV can float on the water surface or dive underwater. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 This is a schematic diagram of the water-air amphibious vector UAV of the present invention;

[0029] Figure 2 This is a perspective view of the water-air amphibious vector UAV of the present invention;

[0030] Figure 3 This is the main view of the water-air amphibious vector UAV of the present invention;

[0031] Figure 4 This is a left view of the water-air amphibious vector UAV of the present invention;

[0032] Figure 5 This is a top view of the water-air amphibious vector UAV of the present invention;

[0033] Figure 6 This is a schematic diagram of the air-water amphibious vector UAV frame of the present invention;

[0034] Figure 7 This is a front view of the air-water amphibious vector UAV frame of the present invention;

[0035] Figure 8 It is a schematic diagram of the upper wing surface of the water-air amphibious vector UAV of the present invention.

[0036] Description of reference numerals:

[0037] 1-Upper wing shell, 2-Frame, 3-Servo motor, 4-Brushless DC motor, 5-Foldable propeller, 6-Rechargeable battery, 7-Servo motor support, 8-Flight control hardware, 9-Lower wing shell, 10-Wire hole, 11-Electronic equipment mounting seat, 12-Exhaust hole DETAILED DESCRIPTION

[0038] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making any creative efforts shall fall within the scope of protection of the present invention.

[0039] This example is an amphibious vector drone. The specific implementation plan is as follows:

[0040] like Figure 1 and Figure 2 As shown, the present invention's amphibious vector drone utilizes a rudderless, dual-rotor flying wing layout. It consists of a frame 2, wings, two brushless DC motors 4, two servo motors 3 serving as steering gears, a rechargeable battery 6, flight control hardware 8, an electronic speed regulator, and two foldable propellers 5. The servo motors provide vector drive, adjusting the propeller axis's deflection direction. Specifically, the steering gears can change the direction of propeller tension, thereby providing vector power to the drone. The brushless DC motors 4 control the propeller's speed. The wings are divided into an upper wing shell 1 and a lower wing shell 9. The wing's planar shape is designed to mimic the shape of a manta ray, and its streamlined shape effectively reduces pressure differential drag during drone flight. The wing has a root chord length of 200 mm, a span of 260 mm, and a tip-toe ratio of 3.6.

[0041] The wing is slightly thicker in the middle and thinner on both sides. The wing is divided into a middle wing section and outer wing sections on the left and right sides, a total of three sections. Among them, the middle wing section is located in the middle of the wing, and the outer wing sections are located on the left and right sides of the middle wing section of the wing. Figure 5 or Figure 8 As shown, the center wing section has a straight leading edge and no sweep angle, and is 128mm long. The length of the center wing section is determined by the selected propeller size. The motors are mounted on the left and right sides of the center wing section. Therefore, the center wing section length needs to be slightly larger than the selected propeller diameter to ensure that the left and right propellers do not interfere with each other during operation. Compared to the outer wing sections, the center wing section is thicker, providing ample space for mounting onboard electronics such as flight control hardware, batteries, and the electronic speed controller. The outer wing sections utilize a thinner, low-Reynolds-number, high-lift-to-drag airfoil, which improves the overall aerodynamic efficiency and enhances the performance of the drone. The outer wing section has a root chord length of 160mm, a follow-to-tip ratio of 2.8, no setback angle, and no twist angle. The upper wing surface is smoothly tangent to the lower wing surface at the transition between the inner and outer sections, while the lower wing surface has a smooth transition. The outer wing section has a swept leading edge, with a continuously variable sweep angle between 20° and 50°. Because the lower half of the chord line of the middle wing section is thicker, when the drone floats on the water, water will not enter the hollow structure between the upper and lower wings through the gaps at the side end surface and the trailing edge of the wing, and the drone can remain floating on the water.

[0042] The schematic diagram of the frame 2 of the water-air amphibious vector UAV of the present invention is as follows Figure 6As shown. The frame 2 is designed as a frame structure. By designing the shape of the frame 2, the overall drainage quality of the drone can be adjusted, thereby achieving sinking and floating in the water. The frame 2 is set in the middle position of the wing near the front end, and is used to support the upper and lower wing shells and install flight control hardware 8 and servo motor 3. An electronic equipment mounting seat 11 is provided inside the frame 2 for installing flight control hardware 8, battery 6 and electronic speed regulator and other airborne electronic equipment; a frame waterproof membrane is pasted on the side of the frame structure of the frame 2, and a complete closed cavity is formed between the frame waterproof membrane and the upper and lower wing shells. When the drone is sailing underwater, the cavity remains dry, which can effectively protect the safety of the flight control hardware 8 and battery 6. The design of the side of the wing and the frame depends on the choice of the wing plane shape and airfoil. The frame of the frame should be completely in fit with the inner surface of the upper and lower shells of the wing to achieve effective support and waterproofing.

[0043] In the area outside the closed cavity formed with the waterproof membrane of the frame, a hollow structure is formed between the upper and lower wing surfaces. The side end surfaces of the wing are not sealed, and a 2mm gap is left at the trailing edge. Water can enter the hollow structure between the upper and lower wing surfaces through the gap between the side end surfaces and the trailing edge of the wing, achieving the effect of the traditional amphibious UAV displacement mechanism. The ridgeline of the frame needs to be designed according to the overall mass and density of the UAV, so as to adjust the overall density of the UAV to be equivalent to the density of the water body during operation, so that the UAV can be completely submerged in water. The ridgeline of the frame should not exceed 40% of the distance from the leading edge to the trailing edge to ensure that the center of gravity of the UAV is before the aerodynamic center and to ensure the static stability of the entire machine. Since there is a gap between the upper and lower wing shells at the trailing edge, in order to maintain the structural strength at the trailing edge and reduce the deformation of the trailing edge induced by aeroelasticity, a plastic block of the same height as the gap is pasted at intervals of 20mm at the trailing edge to connect the upper and lower wing shells, thereby increasing the stiffness at the trailing edge. Figure 7 As shown, two exhaust holes are symmetrically opened at the transition between the inner and outer sections of the upper wing surface to facilitate air circulation when the amphibious vector drone enters and exits the water. The inner surface of the wing is coated with a hydrophobic material. When the drone transitions from the water environment to the air, it can speed up the discharge of water from the hollow structure between the upper and lower wing shells and prevent water from remaining in the hollow structure. The leading edge positions on both sides of the frame are reserved for installing servo motors. Figure 8 As shown, a hole is opened in the base of the rack servo motor installation position. This hole is reserved for the wires of the brushless DC motor and the servo motor. The hole diameter is 4mm to ensure that 5 power supply wires can pass through.

[0044] The above-mentioned cross-medium navigation control scheme of the water-air amphibious vector UAV is as follows:

[0045] The amphibious vector drone of the present invention operates in two different modes in aquatic environments: surface navigation and underwater stealth. Depending on the drone's operating mode in aquatic environments, different control methods are adopted, allowing the drone to contact the water surface in different postures to achieve transitions from air to water and vice versa.

[0046] When the drone transitions from aerial flight mode to surface navigation mode, it maintains a level flight attitude, gradually reducing the speed of the brushless DC motor 4 and lowering the drone's altitude. Before contacting the water surface, the servo motor 3 controls the angle between the propeller 5 axis and the drone's wing chord to control the drone's attitude, ensuring its angle of attack is no greater than 30°, ensuring that the drone's belly first contacts the water surface. Upon contact with the water surface, the resistance experienced by the drone suddenly increases, causing a sudden change in the drone's acceleration along the horizontal plane. This sudden change in horizontal acceleration can be read by the onboard accelerometer in the flight control hardware. After reading this, power to the brushless DC motor 4 is stopped. After the drone loses power, its horizontal speed rapidly decreases, and its lift plummets. Because the drone's center of mass is located 25% of the chord line of the middle wing section, gravity pulls the drone's belly near the leading edge into contact with the water, keeping the drone's trailing edge above the water. This prevents water from entering the hollow structure between the upper and lower wing shells from the trailing edge. Furthermore, because the middle wing section is thicker below the chord line, the belly below the middle wing section generates sufficient buoyancy to keep the drone afloat, preventing water from flowing into the hollow structure through the gaps in the wing's side surfaces. Therefore, the drone can remain afloat while navigating.

[0047] When the drone transitions from aerial flight mode to underwater stealth mode, servo motor 3 adjusts the drone's attitude, allowing it to fly in rotor mode. This ensures that the angle between the drone's wing chord and the horizontal is greater than 70°, with the flight maintained by the force generated by propeller 5. The speed of brushless DC motor 4 is gradually reduced, causing the drone's flight altitude to slowly descend. The trailing edge first contacts the water surface. Because the wing's side end faces are not sealed and there are pre-existing vents at the leading edge of the upper wing, water can enter the hollow structure between the upper and lower wing shells through the gap between the trailing edge and the side end faces. As water continues to enter the hollow structure between the upper and lower wing shells, the density within the drone's wing envelope gradually increases. When the water completely fills the cavity, the transition from aerial flight to underwater stealth is complete. At this point, the drone's overall density is comparable to the density of the water, allowing it to float in the water.

[0048] When the water-air amphibious vector drone transitions from surface navigation to air flight, the servo motor 3 is controlled so that the axis of the propeller 5 is in a vertical position and in the direction of the propeller 5 pulling force, and then the speed of the left and right brushless DC motors 4 is increased synchronously. Under the action of the propeller 5 pulling force, the drone leaves the water surface, takes off vertically, and after reaching the specified height, it switches to a level flight state.

[0049] When the amphibious vector drone transitions from underwater navigation to aerial flight, the servo motor 3 controls the propeller 5 to exert a vertical upward force. Under the force of the propeller 5, the drone continuously rises, with the chord of the drone's wings nearly perpendicular to the water surface, and the nose of the drone pointing upward. Once the propeller 5 clears the water, the speed of the brushless DC motor 4 is reduced, allowing the drone to slowly leave the water. Under the influence of gravity, water flows out of the drone's hollow structure through the gaps between the wing end faces and the trailing edge. Once the trailing edge of the drone clears the water, it takes off using a rotor takeoff, completing the transition from underwater navigation to aerial flight.

[0050] The aforementioned control method for the drone can be implemented by establishing a six-degree-of-freedom dynamic model for the drone. This model incorporates the drone's gravity, buoyancy and the torque it exerts on its center of mass when navigating underwater, vector dynamic forces and torques, as well as the aerodynamic forces in mid-flight and the hydrodynamic forces underwater. Based on this dynamic model, an effective control ratio is designed to achieve integrated control of the drone across both air and water.

[0051] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A water-air amphibious vector drone, characterized in that: The invention adopts a vector twin-rotor flying wing layout, including a frame, a frame waterproof membrane, wings, a steering gear, a motor, a foldable propeller, flight control hardware, a battery and an electronic speed regulator. The steering gear provides vector drive, and the wings include an upper wing shell and a lower wing shell. The upper and lower wing shells are respectively arranged above and below the frame, and the frame is located in the middle of the wing shell near the leading edge to form a complete aerodynamic shape. The frame waterproof membrane is attached to the side of the frame, and a closed cavity is formed between the frame waterproof membrane and the upper and lower wing shells for installing flight control hardware, electronic speed regulator and battery. In the area outside the closed cavity, a hollow structure is formed between the upper and lower wing shells, and the side end surface and trailing edge of the wing are not sealed, so that water can freely enter the hollow structure formed by the upper and lower wing shells. The overall shape of the wing is a structure that is slightly thicker in the middle and thinner on both sides. The middle section is thicker, with sufficient internal space to install batteries, flight control hardware and electronic speed controllers. The left and right sides of the middle section are outer wing sections with thinner low-Rayleau number and high lift-to-drag ratio airfoils. A smooth transition is used between the middle section and the outer wing sections. The plane of the wing is a planar structure imitating a manta ray, and is a pentagon with streamlined characteristics, and both sides of the leading edge of the wing are swept back.

2. The water-air amphibious vector drone according to claim 1, characterized in that: The sweep angle is between 20 and 50 degrees; the trailing edge of the wing is swept forward, with a sweep angle between 20 and 40 degrees.

3. The water-air amphibious vector drone according to claim 2, characterized in that: The frame is a frame structure, the shape of which is determined by the shape of the wing and needs to be designed in conjunction with the wing; an electronic equipment mounting seat is provided in the frame for installing flight control hardware, batteries and an electronic speed regulator.

4. The water-air amphibious vector drone according to claim 3, characterized in that: The left and right servos are installed on the motor mounting brackets on both sides of the frame and are distributed at both ends of the leading edge of the wing. Through vector power, the drone can be controlled to float and sink underwater, as well as to control its attitude during flight in the air.

5. A cross-medium navigation control method for an amphibious vector drone according to any one of claims 1 to 4, characterized in that: include: Control the water-air amphibious vector drone to transition from an air flight state to a water navigation state, and control the water-air amphibious vector drone to transition from a water navigation state to an air flight state, wherein the water navigation state includes surface gliding and underwater diving.

6. The control method according to claim 5, characterized in that: When the water-air amphibious vector drone transitions from an aerial flight state to surface navigation, the drone's attitude is adjusted by a servo to keep it in a level flight state, and the flight altitude is continuously lowered so that the belly of the drone contacts the water surface first, thereby achieving the drone's landing on the water surface; after landing on the water surface, the servo adjusts the propeller's deflection angle to keep the propeller's axis parallel to the water surface and the motor rotating, thereby enabling the drone to sail on the water surface by relying on the pulling force generated by the propeller.

7. The control method according to claim 5, characterized in that: When the water-air amphibious vector drone transitions from an aerial flight state to an underwater dive, the servo adjusts the drone's flight attitude so that the drone flies in a rotor mode, that is, the drone's wing chord is nearly perpendicular to the water surface; the left and right propellers maintain the same rotational speed and gradually reduce the rotational speed to slowly lower the drone's flight altitude until the drone eventually contacts the water surface; because the angle between the drone's wing chord and the water surface is large, the trailing edge of the wing contacts the water surface first; After the trailing edge of the wing contacts the water surface, water enters the hollow structure between the upper and lower wing shells through the gap between the upper and lower wing shells at the trailing edge, thereby increasing the overall density of the wing envelope; After the drone contacts the water surface, the propeller speed is slowly reduced until the drone is completely submerged in the water, completing the transition from air to water navigation. After the drone is completely immersed in water, the vector motor is used again to adjust the drone's posture so that the angle between the drone's wing chord and the water surface is maintained within a smaller range. The drone is then driven underwater using the same driving mode and control method as when the drone is flying in the air.

8. The control method according to claim 5, characterized in that: When the water-air amphibious vector drone transitions from surface navigation to air flight, the propeller axis is controlled by the servo to be in a vertical position and in the direction of the propeller pull, and then the speed of the motors on the left and right sides is increased synchronously. The drone leaves the water surface under the action of the propeller pull, then takes off vertically, and after reaching the specified height, it switches to a level flight state.

9. The control method according to claim 5, characterized in that: When the water-air amphibious vector drone transitions from underwater stealth to aerial flight, the propeller pull is vertically upward by controlling the servo. Under the action of the propeller pull, the drone continuously rises, and the chord line of the drone's wings becomes nearly perpendicular to the water surface, with the drone's nose pointing upward. When the propeller leaves the water, the motor speed is reduced, causing the drone to slowly leave the water. Under the action of gravity, water flows out of the hollow structure of the drone through the gaps between the side end surface and the trailing edge of the wing; When the trailing edge of the drone leaves the water, it takes off using a rotor takeoff method, thus completing the transition of the drone from underwater navigation to air flight mode.

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