Variable wing-shaped composite wing vertical take-off and landing unmanned aerial vehicle

Abstract

The invention provides a variable wing-shaped composite wing vertical take-off and landing unmanned aerial vehicle which is characterized in that a fuselage structure is a spatial tetrahedral structure, and the tetrahedral structure comprises a triangular bottom surface structure and a spatial triangular pyramid structure located above the triangular bottom surface structure; three bottom edges of the spatial triangular pyramid structure are three edges of the triangular bottom surface structure; the lift structure is arranged at the top of the straight line where the gravity center of the fuselage structure is located; the thrust structure provides thrust for flight of the unmanned aerial vehicle; the folding and unfolding horizontal wings can be folded and unfolded. Therefore, gravity center stability and structural strength are guaranteed through the space tetrahedron fuselage structure, the lift force structure provides lift force during vertical take-off and landing, the horizontal wings are folded to reduce interference, and the lift force structure is inclined to cooperate with the unfolded horizontal wings to improve aerodynamic efficiency during horizontal flight. The folding and unfolding horizontal wing capable of being dynamically adjusted can prevent attitude instability by actively adjusting pneumatic layout in low-altitude turbulent flow.

Description

Technical Field

[0001] The present invention relates to the technical field of unmanned aerial vehicles, and in particular, to a variable airfoil compound wing vertical takeoff and landing unmanned aerial vehicle. Background Art

[0002] Vertical takeoff and landing unmanned aerial vehicles have important application values in complex environment operations. However, the existing technologies still face prominent problems that it is difficult to balance aerodynamic efficiency and flight modes. Traditional multi-rotor unmanned aerial vehicles have flexible vertical takeoff and landing, but their aerodynamic efficiency is low during horizontal flight. Compound wing designs such as tilt-rotor wings attempt to integrate the advantages of both, but there are some flight transition blind spots. At the same time, existing compound wing unmanned aerial vehicles often adopt fixed folding wing designs, and their wingspans and aerodynamic shapes cannot be dynamically adjusted according to flight stages, which may increase aerodynamic interference during vertical takeoff and landing, and it is difficult to fully expand during horizontal flight to optimize the lift-to-drag ratio. Especially in a low-altitude turbulent flow environment, this rigid structure is likely to cause flight attitude instability. The lack of an actively adjustable aerodynamic layout in the existing technologies limits the mode switching performance.

[0003] Therefore, it is necessary to provide an unmanned aerial vehicle to solve the problems existing in the existing technologies. Summary of the Invention

[0004] The main object of the present invention is to provide a variable airfoil compound wing vertical takeoff and landing unmanned aerial vehicle, so as to at least solve the problem that the fixed folding wing in the existing technology is likely to cause flight attitude instability.

[0005] To achieve the above object, the present invention provides a variable airfoil compound wing vertical takeoff and landing unmanned aerial vehicle, including: a fuselage structure, the fuselage structure being a spatial tetrahedron structure, the tetrahedron structure including a triangular bottom surface structure and a spatial triangular pyramid structure located above the triangular bottom surface structure; three bottom edges of the spatial triangular pyramid structure being three sides of the triangular bottom surface structure; a lift structure, the lift structure being arranged at the top of the straight line where the center of gravity of the fuselage structure is located, the lift structure being used to provide lift for the unmanned aerial vehicle, and the angle of the lift structure being adjustable; a thrust structure, the thrust structure being arranged at three vertices of the triangular bottom surface structure, the thrust structure being used to provide thrust for the flight of the unmanned aerial vehicle; retractable horizontal wings, the retractable horizontal wings being symmetrically arranged on both sides of the triangular bottom surface structure, and the retractable horizontal wings being retractable and deployable.

[0006] Optionally, the triangular bottom surface structure includes three first beams, and the three first beams are sequentially connected end to end;

[0007] The described space triangular pyramid structure includes three second beams. The first ends of the three second beams are respectively connected to the first connection positions where the three first beams are pairwise connected. The second ends of the three second beams intersect at a second connection position, and the second connection position is located on a straight line perpendicular to the plane where the bottom surface structure is located and passing through the center of gravity of the bottom surface structure.

[0008] Optionally, the triangular bottom surface structure further includes three third beams. The first ends of the three third beams are commonly connected to the position where the center of gravity of the bottom surface structure is located, and the second ends of the three third beams are respectively connected to the three first connection positions.

[0009] Optionally, the lift structure includes:

[0010] A first motor, which is installed at the position where the center of gravity of the triangular bottom surface structure is located and is used to output driving force;

[0011] A clutch, the input shaft of which is connected to the output shaft of the first motor;

[0012] A universal joint, the input shaft of which is connected to the output shaft of the clutch;

[0013] A dual-rotor structure, the input shaft of the rotating shaft of which is connected to the output shaft of the universal joint. Two groups of rotors are vertically distributed on the rotating shaft, and the rotation directions of the two groups of rotors are opposite;

[0014] Wherein, the direction of the output shaft of the universal joint can be adjusted.

[0015] Optionally, the thrust structure includes:

[0016] Three second motors, which are evenly distributed around the first motor;

[0017] Three connecting shafts, each of which is correspondingly connected to the output shaft of one of the second motors; each connecting shaft is correspondingly parallel to each of the third beams;

[0018] Three propellers, each of which is correspondingly sleeved on each of the connecting shafts.

[0019] Optionally, the retractable horizontal wing includes:

[0020] A horizontal shaft, which is symmetrically arranged at one of the first connection positions;

[0021] Two rotating pin shafts, which are respectively arranged at both ends of the horizontal shaft;

[0022] Two sets of triangular wing surfaces are respectively arranged on both sides of the two first beams that form the first connection position; the top ends of each set of triangular wing surfaces are correspondingly connected to a rotating pin shaft; each set of triangular wing surfaces includes a triangular skin and a plurality of rib beams that support the skin; the first ends of the plurality of rib beams are sequentially connected to a rotating pin shaft, so that the plurality of rib beams rotate around the rotating pin shaft in the plane where the triangular bottom surface structure is located and unfold into a fan shape;

[0023] Two sets of push rod drive structures, each set of push rod drive structures is connected to a set of triangular wing surfaces and is used to control the unfolding and retracting of the corresponding triangular wing surfaces.

[0024] Optionally, the push rod drive structure includes:

[0025] A first push rod mechanism, the push rod of the first push rod mechanism is connected to the outermost rib beam of the corresponding triangular wing surface. When the first push rod mechanism is pushed out, the corresponding triangular wing surface unfolds and the triangular wing surface is coplanar with the triangular bottom surface structure; when the first push rod mechanism is retracted, the corresponding triangular wing surface retracts to one side of the corresponding first beam;

[0026] A second push rod mechanism, the push rod of the second push rod mechanism is connected to the second end of the innermost rib beam of the corresponding triangular wing surface. When the push rod of the second push rod mechanism is pushed out, the push rod of the second push rod mechanism inclines downward to the triangular bottom surface structure, so that the corresponding triangular wing surface faces the wind.

[0027] Optionally, the length of the second beam is less than or equal to the length of the first beam.

[0028] Optionally, the length of the rotating shaft is 1 / 5 to 1 / 3 times the distance from the center of gravity to the second connection position;

[0029] The diameter of the circle formed by the rotation trajectory of the rotor blade tip is 0.9 to 1.2 times the length of the first beam.

[0030] Optionally, the length of the connecting shaft is 1 / 5 to 1 / 3 times the distance from the center of gravity to the first connection position;

[0031] The diameter of the circle formed by the rotation trajectory of the propeller blade tip is 1.5 to 2 times the length of the connecting shaft.

[0032] A variable-wing composite-wing vertical takeoff and landing unmanned aerial vehicle according to the solution of the present invention includes: a fuselage structure, the fuselage structure is a spatial tetrahedron structure, and the tetrahedron structure includes a triangular bottom surface structure and a spatial triangular pyramid structure located above the triangular bottom surface structure; the three bottom edges of the spatial triangular pyramid structure are the three sides of the triangular bottom surface structure; a lift structure, the lift structure is arranged at the top of the straight line where the center of gravity of the fuselage structure is located, and the lift structure is used to provide lift for the unmanned aerial vehicle, and the angle of the lift structure is adjustable; a thrust structure, the thrust structure is arranged at the three vertices of the triangular bottom surface structure, and the thrust structure is used to provide thrust for the flight of the unmanned aerial vehicle; retractable horizontal wings, the retractable horizontal wings are symmetrically arranged on both sides of the triangular bottom surface structure, and the retractable horizontal wings can be retracted and deployed. Thus, the center-of-gravity stability and structural strength are ensured by the spatial tetrahedron fuselage structure. The lift structure with variable angle located at the top of the center of gravity works in cooperation with the retractable horizontal wings. When taking off and landing vertically, the lift structure provides lift and the horizontal wings are retracted to reduce interference. When flying horizontally, the lift structure is tilted to cooperate with the deployed horizontal wings to improve the aerodynamic efficiency. The dynamically adjustable retractable horizontal wings can prevent attitude instability by actively adjusting the aerodynamic layout in low-altitude turbulence. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0034] Figure 1 is a schematic diagram of the fuselage structure of a variable-wing composite-wing vertical takeoff and landing unmanned aerial vehicle according to an optional embodiment of the present invention;

[0035] Figure 2 is a top view schematic diagram of the deployed retractable horizontal wings of a variable-wing composite-wing vertical takeoff and landing unmanned aerial vehicle according to an optional embodiment of the present invention;

[0036] Figure 3 is a front view schematic diagram of the deployed retractable horizontal wings of a variable-wing composite-wing vertical takeoff and landing unmanned aerial vehicle according to an optional embodiment of the present invention;

[0037] Figure 4 is a front view schematic diagram of the tilted rotor of a variable-wing composite-wing vertical takeoff and landing unmanned aerial vehicle according to an optional embodiment of the present invention;

[0038] Figure 5 is a top view schematic diagram of the retracted retractable horizontal wings of a variable-wing composite-wing vertical takeoff and landing unmanned aerial vehicle according to an optional embodiment of the present invention;

[0039] Figure 6 is a front view schematic diagram of the retracted retractable horizontal wings of a variable-wing composite-wing vertical takeoff and landing unmanned aerial vehicle according to an optional embodiment of the present invention.

[0040] Reference numerals:

[0041] 10. Airframe structure; 11. First beam; 12. Second beam; 13. Third beam; 20. Retractable horizontal wing; 21. Horizontal axis; 22. Rotating pin shaft; 23. Triangular wing surface; 231. Skin; 232. Bone beam; 24. Push rod drive structure; 241. First push rod mechanism; 242. Second push rod mechanism; 30. Lift structure; 31. Twin-rotor structure; 311. Rotor; 312. Rotating shaft; 32. Universal joint; 40. Thrust structure; 41. Connecting shaft; 42. Propeller. Detailed implementation mode

[0042] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the drawings and in conjunction with the embodiments.

[0043] As Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 6 shown, a variable-wing composite wing vertical takeoff and landing unmanned aerial vehicle includes: an airframe structure 10, the airframe structure 10 is a space tetrahedron structure, the tetrahedron structure includes a triangular bottom surface structure and a space triangular pyramid structure located above the triangular bottom surface structure; the three bottom edges of the space triangular pyramid structure are the three sides of the triangular bottom surface structure; a lift structure 30, the lift structure 30 is arranged at the top of the straight line where the center of gravity of the airframe structure 10 is located, the lift structure 30 is used to provide lift for the unmanned aerial vehicle, and the angle of the lift structure 30 is adjustable; a thrust structure 40, the thrust structure 40 is arranged at the three vertices of the triangular bottom surface structure, the thrust structure 40 is used to provide thrust for the flight of the unmanned aerial vehicle; retractable horizontal wings 20, the retractable horizontal wings 20 are symmetrically arranged on both sides of the triangular bottom surface structure, and the retractable horizontal wings 20 can be retracted and deployed.

[0044] Specifically, the airframe structure 10 of the unmanned aerial vehicle in this application is a space tetrahedron structure, composed of a triangular bottom surface and a space triangular pyramid above. This structure makes the center of gravity of the unmanned aerial vehicle stable, can evenly disperse the forces during flight, enhance the overall structural strength, and ensure safe and reliable flight.

[0045] The lift structure 30 of the unmanned aerial vehicle is located directly above the center of gravity of the airframe. It provides the main lift during vertical takeoff and landing, and cooperates with the horizontal wings to provide lift during horizontal flight; the thrust structure 40 is installed at the three vertices of the triangular bottom surface structure and is responsible for providing thrust in the horizontal direction, enabling the unmanned aerial vehicle to fly forward. The two work together to ensure the power requirements of the unmanned aerial vehicle at different flight stages.

[0046] The retractable horizontal wings 20 are symmetrically arranged on both sides of the triangular bottom structure and can be switched between the retracted and deployed states. When retracted, they are attached to the side of the fuselage to reduce air resistance during flight; when deployed, they are deployed forward to form a fan shape, increasing the wing area, enhancing the lift effect, and improving the performance of the UAV during horizontal flight.

[0047] For the UAV in this application, the spatial tetrahedron fuselage structure 10 ensures the center of gravity stability and structural strength. The lift structure 30 with variable angle located at the top of the center of gravity works in coordination with the retractable horizontal wings 20. During vertical takeoff and landing, the lift structure 30 provides lift and the horizontal wings are retracted to reduce interference. During horizontal flight, the lift structure 30 tilts to cooperate with the deployed horizontal wings to improve the aerodynamic efficiency, solving the problem of low aerodynamic efficiency of traditional multi-rotors 311 during horizontal flight. The dynamically adjustable retractable horizontal wings 20 avoid the disadvantages of traditional composite wings with fixed folding wings, which increase aerodynamic interference during vertical takeoff and landing and cannot be fully deployed during horizontal flight to optimize the lift-to-drag ratio. Moreover, it can prevent attitude instability by actively adjusting the aerodynamic layout in low-altitude turbulence.

[0048] In a possible implementation manner, the triangular bottom structure includes three first beams 11, and the three first beams 11 are sequentially connected end to end.

[0049] The spatial triangular pyramid structure includes three second beams 12. The first ends of the three second beams 12 are respectively connected to the first connection positions where the three first beams 11 are pairwise connected. The second ends of the three second beams 12 intersect at the second connection position, and the second connection position is located on the straight line perpendicular to the plane where the bottom structure is located and passing through the center of gravity of the bottom structure.

[0050] Specifically, the triangular bottom structure is composed of three first beams 11 sequentially connected end to end to form an equilateral triangle framework, providing stable basic support and balanced load distribution. The spatial triangular pyramid structure connects the three vertices of the equilateral triangle framework to the top center of gravity position through three second beams 12. The second beams 12 intersect at the second connection position directly above the center of gravity of the bottom surface, enabling the lift generated by the lift structure 30 to be directly transmitted to the bottom framework through the triangular pyramid structure, effectively reducing structural torsion and vibration. At the same time, the shortened force transmission path reduces energy loss. Among them, each vertex is the first connection position.

[0051] In a possible implementation manner, the triangular bottom structure further includes three third beams 13. The first ends of the three third beams 13 are commonly connected to the position where the center of gravity of the bottom structure is located, and the second ends of the three third beams 13 are respectively connected to the three first connection positions.

[0052] Specifically, one end of the three third beams 13 converges at the bottom surface center of gravity, and the other end is connected to the connection position of each first beam 11 and the second beam 12, that is, the first connection position, forming a central radial support structure, so that the center of gravity of the fuselage and the lift center are accurately aligned, ensuring that the lift generated by the lift structure 30 is directly transmitted to the bottom surface center of gravity through the spatial triangular pyramid structure and the second beam 12, greatly reducing the risk of fuselage torsion caused by moment imbalance. At the same time, the third beam 13 acts as a reinforcing rib to strengthen the overall rigidity of the triangular bottom surface structure, so that the horizontal thrust generated by the thrust structure 40 can be efficiently transmitted to the entire fuselage structure 10; in the process of retracting and unfolding the retractable horizontal wing 20, the synergistic effect of the third beam 13 and the spatial triangular pyramid structure ensures the stability of the center of gravity position.

[0053] In a possible embodiment, the lift structure 30 includes: a first motor, which is installed at the center of gravity of the triangular bottom structure and is used to output driving force; a clutch, the input shaft of the clutch is connected to the output shaft of the first motor; a universal joint 32, the input shaft of the universal joint 32 is connected to the output shaft of the clutch; a dual-rotor structure 31, the input shaft of the rotating shaft 312 of the dual-rotor structure 31 is connected to the output shaft of the universal joint 32, and two groups of rotors 311 distributed vertically are installed on the rotating shaft 312, and the two groups of rotors 311 rotate in opposite directions; wherein the output shaft direction of the universal joint 32 is adjustable.

[0054] Specifically, the first motor is installed at the center of gravity of the triangular bottom structure to ensure the balance and stability of the power output. Its output shaft is directly connected to the input shaft of the clutch, forming the starting link of power transmission. The clutch is fully engaged during the vertical take-off and landing phase, allowing the power of the motor to be transmitted to subsequent components through itself; it is separated in time during the horizontal flight phase to create conditions for the adjustment of the power transmission path.

[0055] The universal joint 32 is connected to the output shaft of the clutch, and its input shaft is closely matched with the clutch to receive power from the clutch. The direction of the output shaft of the universal joint 32 can be flexibly adjusted according to the flight state, so that the drone can accurately match the required aerodynamic requirements in different flight modes, keep the output shaft horizontal during vertical take-off and landing, and provide stable power input for the dual rotor structure 31; the universal joint 32 changes its output shaft direction during horizontal flight, allowing the rotor 311 to generate a horizontal component force to push the drone forward.

[0056] The universal joint 32 can change the direction of the output shaft driven by the steering gear, and the angle is not greater than 10°. The output shaft of the universal joint 32 is a sleeve shaft, and the rotation direction is converted by a gear mechanism. The rotation direction of its core shaft is opposite to that of the sleeve shaft. The core shaft and the sleeve shaft of the output shaft of the universal joint 32 are respectively connected to the core shaft and the sleeve shaft of the rotating shaft 312. The upper rotor 311 in the dual-rotor structure 31 is installed at the top of the sleeve shaft, and the lower rotor 311 is installed at the top of the core shaft, and the two are vertically distributed. When the power of the first motor is transmitted to the universal joint 32, it is adjusted by the universal joint 32 and then transmitted to the rotating shaft 312. Driven by the power, the core shaft and the sleeve shaft of the rotating shaft 312 start to rotate in opposite directions. The reverse rotation of the two groups of rotors 311 effectively cancels out the torque generated by the rotors 311 on the one hand, avoiding the problem of the fuselage torsion caused by the torque imbalance of the drone, and ensuring the stability of the drone during flight.

[0057] During the vertical takeoff and landing stage, the clutch is in the engaged state, and the power is transmitted from the first motor through the clutch and the universal joint 32 to the dual-rotor structure 31. At this time, the universal joint 32 keeps the output shaft horizontal. Driven by the power, the two groups of rotors 311 generate vertical lift in coordination with the rotation of the sleeve shaft and the core shaft, enabling the drone to take off vertically stably or land safely. During the horizontal flight stage, the clutch is disengaged, and the power transmission path changes. The universal joint 32 adjusts the direction of the output shaft driven by the steering gear, making the rotor 311 tilt relative to the triangular bottom structure and form a certain angle of attack with the horizontal flight direction. At this time, during the rotation of the rotor 311, in addition to its own rotational lift, a lift component with an angle of attack with the flight direction will also be generated. This component and the horizontal thrust generated by the bottom thrust structure 40 act together to provide power for the drone to fly forward, thus realizing efficient forward flight. By dynamically adjusting the angle and rotation mode of the rotor 311, the problem of power interruption existing in the traditional compound-wing drone during mode switching is solved, the smooth transition between vertical takeoff and landing and horizontal flight is realized, and at the same time, the flight stability of the drone in a complex aerodynamic environment is ensured.

[0058] In a possible implementation manner, the thrust structure 40 includes: three second motors, which are evenly distributed around the first motor; three connecting shafts 41, each of the connecting shafts 41 is correspondingly connected to the output shaft of one of the second motors; each of the connecting shafts 41 is correspondingly parallel to each of the third beams 13; three propellers 42, each of the propellers 42 is correspondingly sleeved on each of the connecting shafts 41.

[0059] Specifically, the three second motors are evenly distributed around the first motor. Each second motor drives the corresponding propeller 42 through an independent connecting shaft 41, forming three groups of horizontally thrust units symmetrically distributed. The parallel arrangement of the connecting shaft 41 and the third beam 13 enables precise control of the thrust direction. The horizontal thrusts generated by the three propellers 42 constitute a stable planar force system, which can not only achieve precise heading adjustment (front-back, left-right movement) of the UAV in the horizontal plane through differential control, but also provide efficient forward flight power through synchronous acceleration, reducing the risk of single-point failure. When a certain motor fails, the other motors can compensate for the deflection torque through vector thrust. The composite layout of the three groups of thrust units and the top lift enables the UAV to have multi-directional maneuverability (vertical takeoff and landing + horizontal flight + hovering in place) and precise controllability, solving the problem of insufficient horizontal thrust of traditional multi-rotors 311. At the same time, the parallel beam structure enhances the torsional stiffness of the fuselage, ensuring the stability of thrust transmission in a complex aerodynamic environment.

[0060] In a possible implementation manner, the deployable horizontal wing 20 includes: a transverse shaft 21 symmetrically disposed at one of the first connection positions; two rotating pin shafts 22 respectively disposed at both ends of the transverse shaft 21, and the rotating pin shafts 22 can rotate in the plane where the triangular bottom surface structure is located; two groups of triangular wing surfaces 23 respectively disposed on both sides of the two first beams 11 constituting the first connection position; the top end of each group of triangular wing surfaces 23 is correspondingly connected to one of the rotating pin shafts 22; each group of triangular wing surfaces 23 includes a triangular skin 231 and a plurality of rib beams 232 supporting the skin 231; the first ends of the plurality of rib beams 232 are sequentially connected to one of the rotating pin shafts 22, so that the plurality of rib beams 232 rotate around the rotating pin shaft 22 in the plane where the triangular bottom surface structure is located and unfold in a fan shape; two groups of push rod driving structures 24, each group of push rod driving structures 24 is connected to one group of triangular wing surfaces 23 and is used to control the deployment and retraction of the corresponding triangular wing surfaces 23.

[0061] Specifically, a transverse axis 21 is symmetrically installed at one of the first connection positions (i.e., the intersection of the first beam 11 and the third beam 13), and a rotating pin 22 is installed at both ends of the transverse axis 21. Two groups of triangular wing surfaces 23 are unfolded or retracted around the corresponding rotating pin 22. The triangular wing surface 23 adopts a composite structure of a triangular skin 231 and a frame beam 232. One end of the frame beam 232 is connected to the rotating pin 22 to form a fan-shaped support system. When unfolded, the frame beam 232 is radially unfolded along the bottom plane, and the skin 231 forms an inverted triangular wing shape, which increases the wing area and effectively improves the lift-drag ratio during low-speed flight; when retracted, the frame beam 232 is attached to the bottom of the triangular bottom structure, and the skin 231 is folded to reduce air resistance. Each group of first push rod mechanisms 241 controls the retraction and unfolding of the corresponding triangular wing surface 23 through a connecting rod mechanism. In the vertical take-off and landing stage, the horizontal wing is folded to reduce aerodynamic interference, and the wing surface is unfolded during horizontal flight to enhance lift stability. In particular, attitude fine-tuning can be achieved by partial unfolding in complex airflow. The skin 231 is made of high-strength, high-density, lightweight, and flexible fabric.

[0062] In a possible implementation, the push rod driving structure 24 includes:

[0063] A first push rod mechanism 241, wherein a push rod of the first push rod mechanism 241 is connected to the outermost bone beam 232 of the corresponding triangular wing surface 23. When the first push rod mechanism 241 is pushed out, the corresponding triangular wing surface 23 is unfolded, and the triangular wing surface 23 is coplanar with the triangular bottom surface structure; when the first push rod mechanism 241 is retracted, the corresponding triangular wing surface 23 is retracted to one side of the corresponding first beam 11;

[0064] The second push rod mechanism 242, the push rod of the second push rod mechanism 242 is connected to the second end of the innermost frame beam 232 of the corresponding triangular wing surface 23, and when the push rod of the second push rod mechanism 242 is pushed out, the push rod of the second push rod mechanism 242 is tilted downward of the triangular bottom surface structure, so that the corresponding triangular wing surface 23 faces the wind.

[0065] Specifically, the first push rod mechanism 241 is connected to the outermost spar 232 of the triangular wing surface 23. Its horizontal pushing action causes the wing surface to unfold along the plane of the triangular bottom structure until it is coplanar with the triangular bottom structure. At this time, the wingspan is maximized to increase the cruise lift; when retracted, the wing surface fits against the fuselage to reduce drag. The second push rod mechanism 242 acts on the end of the innermost spar 232. Its vertical pushing causes the wing surface to tilt downward to form a windward angle of attack, enhancing the lift efficiency during low-speed flight. Through the coordinated control of the push rod stroke, the aerodynamic shape can be dynamically adjusted under complex weather conditions - the wing surface is retracted during vertical takeoff and landing to reduce interference, the wing surface is unfolded and the angle of attack is adjusted during horizontal flight to optimize the lift-to-drag ratio, and the wing surface can be actively tilted to form aerodynamic damping when encountering turbulence, ensuring both the aerodynamic stability during high-speed cruising and endowing the UAV with the maneuverability and adaptability in the low-altitude complex environment, solving the drawbacks of traditional fixed-wing UAVs relying on runways for takeoff and landing and the low aerodynamic efficiency of compound-wing models, making the aircraft have both the flexibility of vertical takeoff and landing and the characteristics of efficient cruising.

[0066] Among them, the first push rod mechanism 241 is a first sleeve structure. The first movable member in the first sleeve structure is retractably arranged in the first fixed member and is driven by electricity to extend or retract. There are shafts perpendicular to its radial direction at both ends of the first sleeve structure, which are respectively connected to the triangular bottom structure and the outermost spar 232 of the corresponding retractable horizontal wing 20 through bearings. When the first movable member of the first push rod mechanism 241 fully extends, the axis of the first sleeve structure is perpendicular to the corresponding connected first beam 11, and the corresponding connected retractable horizontal wing 20 is fully unfolded, and the wing surface of the retractable horizontal wing 20 is coplanar with the triangular bottom structure. The second push rod mechanism 242 is a second sleeve structure. The second movable member in the second sleeve structure is retractably arranged in the second fixed member and is driven by electricity to extend or retract. There are shafts perpendicular to its radial direction at both ends of the second sleeve structure, which are respectively connected to the triangular bottom structure and the innermost spar 232 of the corresponding retractable horizontal wing 20 through bearings. When the second movable member of the second push rod mechanism 242 is fully retracted, the axis of the second sleeve structure is perpendicular to the corresponding connected first beam 11, and the corresponding connected retractable horizontal wing 20 is fully retracted to one side of the corresponding first beam 11; when the second movable member of the second push rod mechanism 242 fully extends, the second movable member drives the bottom of the corresponding connected innermost spar 232 to tilt downward towards the plane where the triangular bottom structure is located, and the tilted spar 232 makes the corresponding retractable horizontal wing 20 in a windward state.

[0067] In a possible implementation manner, the length of the second beam 12 is less than or equal to the length of the first beam 11.

[0068] Specifically, from the perspective of structural mechanics, the shorter second beam 12 significantly shortens the lever arm from the second connection position to the center of gravity, enabling the lift generated by the lift structure 30 to be transmitted to the bottom triangular bottom structure more directly and efficiently, reducing the torque amplification effect and structural torsion risk caused by the long lever arm, and enhancing flight stability. Secondly, in terms of aerodynamic performance, the shorter second beam 12 reduces the overall height of the fuselage, decreases the aerodynamic interference between the downwash airflow of the rotor 311 and the fuselage during vertical takeoff and landing, and improves the lift efficiency. Thirdly, in terms of spatial layout, the compact spatial triangular pyramid structure makes the center of gravity distribution of the drone more reasonable. Coupled with the retractable horizontal wing 20 and the thrust structure 40, a smooth transition between vertical takeoff and landing and horizontal flight modes is achieved. Moreover, while ensuring structural strength, the fuselage weight is reduced, which has significant value for extending the endurance time and improving the energy utilization efficiency.

[0069] In a possible implementation manner, the length of the rotation axis 312 is 1 / 5 to 1 / 3 times the distance from the center of gravity to the second connection position;

[0070] The diameter of the circle formed by the tip rotation trajectory of the rotor 311 is 0.9 to 1.2 times the length of the first beam 11.

[0071] Specifically, the reasonable length of the rotation axis 312 ensures that the lift direction generated by the main rotor 311 during vertical takeoff and landing is accurately matched with the center of gravity position, avoiding both the lift offset caused by an overly long axis (which may cause the fuselage to pitch forward or backward) and the insufficient lift caused by an overly short axis (requiring a higher rotation speed for compensation), achieving a balance between lift efficiency and structural stability. Secondly, the tip trajectory diameter of the rotor 311 being 0.9 to 1.2 times the length of the first beam 11 ensures that the rotor 311 can provide sufficient horizontal component force during horizontal flight (by adjusting the tilt angle of the rotor 311) without generating aerodynamic interference with the retractable horizontal wing 20 due to an overly large rotor 311 size. In addition, the shorter rotation axis 312 reduces the mechanical losses of the transmission system, while the moderate rotor 311 size ensures the maximum lift-to-drag ratio under limited power. Generally speaking, the reasonable matching of geometric parameters improves the lift efficiency of the drone, reduces energy consumption, and decreases the flight control difficulty in a complex aerodynamic environment while ensuring flight stability.

[0072] In a possible implementation manner, the length of the connecting shaft 41 is 1 / 5 to 1 / 3 times the distance from the center of gravity to the first connection position;

[0073] The diameter of the circle formed by the tip rotation trajectory of the propeller 42 is 1.5 to 2 times the length of the connecting shaft 41.

[0074] Specifically, the length of the connecting shaft 41 is set to be 1 / 5 to 1 / 3 times the distance from the center of gravity to the first connection position. This not only ensures that the horizontal thrust direction generated by the thrust propeller 42 accurately acts on the center of gravity area, ensuring flight stability, but also avoids structural strength problems and thrust loss caused by an overly long shaft. The tip path diameter of the propeller 42 is set to be 1.5 to 2 times the length of the connecting shaft 41. While avoiding aerodynamic interference with components such as the wing, it ensures that the thrust action range covers the entire fuselage width, enabling the horizontal thrust to be effectively transmitted to the center of gravity of the UAV. In cooperation with the retractable horizontal wing 20 and the thrust structure 40, it realizes the efficient conversion of lift and thrust during vertical takeoff and landing and stable forward flight propulsion during horizontal flight, improving the flight stability and control performance of the UAV.

[0075] The present application is further illustrated by the following embodiments:

[0076] Three identical first beams 11 are respectively detailedly connected to three points A, B, and C, forming an equilateral triangle bottom surface structure of a triangular prism, and point O is the center of gravity. Points A, B, and C are respectively provided with third beams 13 inward along the angle bisectors of the equilateral triangle, corresponding to AO, BO, and CO respectively, and the common connection point of the three third beams 13 is O.

[0077] Three identical second beams 12, corresponding to AT, BT, and CT respectively. The first ends of the three second beams 12 are inclinedly connected to points A, B, and C and form a certain angle with the plane of triangle ABC. The second ends of the three second beams 12 are commonly connected at point T. The three second beams 12 and the three first beams 11 form a spatial triangular pyramid structure.

[0078] Along the OT direction, a short shaft TM of a sleeve shaft structure, that is, the rotating shaft 312, is vertically provided upward from point T. Near point T and point M on the rotating shaft 312, a set of identical three-blade rotors 311 are respectively installed. The rotor 311 near point T is driven by the sleeve shaft of the rotating shaft 312, and the rotor 311 near point M is driven by the core shaft of the rotating shaft 312. That is, the coaxial contra-rotating dual-rotor structure 31 form.

[0079] On the bottom surface with point O as the center of gravity, a first motor is installed. The output shaft of the first motor is perpendicular to the bottom surface upward and is connected to the input shaft of the clutch. The output shaft of the clutch is perpendicular upward to point T, and at this point, it is connected to the input shaft of the universal joint 32. The universal joint 32 can change the output shaft direction driven by the servo, and the angle is not greater than 10°. The output shaft of the universal joint 32 is a sleeve shaft, and the rotation direction is converted through a gear mechanism. The rotation direction of its core shaft is opposite to that of the sleeve shaft. The core shaft and the sleeve shaft of the output shaft of the universal joint 32 are respectively connected to the core shaft and the sleeve shaft of the rotating shaft 312.

[0080] At points A, B, and C, a horizontal connecting shaft 41 is connected in the directions of OA, OB, and OC respectively, and a propeller 42 is coaxially installed at the position where the top of the horizontal connecting shaft 41 is located. Around the first motor, three second motors are evenly distributed and installed. The output shaft of each second motor is in the horizontal direction and is respectively connected to the three connecting shafts 41. The output shaft of the second motor is coaxial with the connecting shaft 41.

[0081] A horizontal shaft 21 perpendicular to the third beam 13 is installed at point A. The horizontal shaft 21 is parallel to the first beam 11 corresponding to BC, and the length of the horizontal shaft 21 is less than 1 / 5 of the length of the first beam 11. There is a shaft for horizontal rotation at each end of the horizontal shaft 21, and a number of bone beams 232 in the same horizontal plane as AB and AC are respectively installed on the two shafts. A high-strength, high-density, lightweight, and flexible fabric skin 231 (similar to an umbrella surface or a silk folding fan) is installed on the bone beams 232. The outermost bone beam 232 has the highest strength, and a first push rod mechanism 241 is respectively installed at the corresponding positions of the bone beam 232 and AB, AC; the tail ends (the far ends from point A) of the innermost bone beams 232 are respectively installed with a second push rod mechanism 242 at the corresponding positions of AB and AC. When the push rod contracts, a group of bone beams 232 pushed by it contract to a position close to AB or AC. When the push rod of the first push rod mechanism 241 extends, multiple bone beams 232 on the corresponding side gradually unfold outward with the shaft as the center until the outermost skeleton reaches a position close to being perpendicular to AO. When the push rod of the second push rod mechanism 242 extends, it pushes the innermost bone beam to tilt downward to the lower part of the triangular bottom structure to form a windward wing surface.

[0082] In this application, when the drone is used for hoisting operations, the dual-rotor structure 31 is power-coupled with the first motor through a clutch. The first motor drives the dual-rotor structure 31 to rotate horizontally through the clutch to generate vertical lift, realizing operations such as ascending, descending, and hovering. At the same time, the three thrust propellers 42 achieve thrust vector control through independent speed regulation, precisely adjusting the attitude and displacement of the drone on the horizontal plane. When the drone switches to the load-carrying flight mode, during the takeoff and ascent stage, the lift mode of the rotor 311 during hoisting is still adopted. After reaching the predetermined level flight altitude, the clutch disengages to cut off the power of the rotor 311. At this time, the first motor drives the universal joint 32 to adjust the direction of the dual-rotor structure 31 under the control of the servo, causing it to tilt at a specific angle of attack to generate a horizontal component force, which, combined with the forward thrust generated by the three thrust propellers 42 at the bottom, jointly propels the drone to fly horizontally. At the same time, the push rod drive mechanism unfolds and retracts the horizontal wing 20 to increase the wing area and improve the cruise lift-drag ratio. Through the intelligent switching of the power system and the dynamic adjustment of the aerodynamic shape, the efficient transition and stable flight of the drone between different flight tasks are realized. Through the coordinated cooperation of the dual-rotor structure 31 system and the thrust propellers 42, as well as the dynamic adaptation of the aerodynamic shape and the power system, the drone is capable of performing hoisting and load-carrying flight tasks in complex environments, ensuring both the vertical takeoff and landing ability and precise hovering performance during hoisting, improving the propulsion efficiency and energy utilization rate of horizontal flight, and at the same time, the design of the retractable horizontal wing 20 effectively reduces the air resistance during the cruise stage and improves the endurance ability.

[0083] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, various changes and modifications can be made to the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A variable-wing composite-wing vertical takeoff and landing unmanned aerial vehicle, characterized in that, Comprising: A fuselage structure, the fuselage structure being a spatial tetrahedron structure, the tetrahedron structure including a triangular bottom surface structure and a spatial triangular pyramid structure located above the triangular bottom surface structure; The three bottom edges of the spatial triangular pyramid structure are the three sides of the triangular bottom surface structure; A lift structure, the lift structure being provided at the top of the straight line where the center of gravity of the fuselage structure is located, the lift structure being used to provide lift for the unmanned aerial vehicle, and the angle of the lift structure being adjustable; A thrust structure, the thrust structure being provided at the three vertices of the triangular bottom surface structure, the thrust structure being used to provide thrust for the flight of the unmanned aerial vehicle; Retractable horizontal wings, the retractable horizontal wings being symmetrically provided on both sides of the triangular bottom surface structure, and the retractable horizontal wings being retractable and deployable.

2. The variable airfoil composite wing vertical takeoff and landing unmanned aerial vehicle according to claim 1, wherein The triangular bottom surface structure includes three first beams, and the three first beams are sequentially connected end to end; The spatial triangular pyramid structure includes three second beams, the first ends of the three second beams are respectively connected to the first connection positions where the three first beams are pairwise connected, and the second ends of the three second beams intersect at a second connection position, and the second connection position is located on the straight line perpendicular to the plane where the bottom surface structure is located and passing through the center of gravity of the bottom surface structure.

3. The variable airfoil composite wing vertical takeoff and landing unmanned aerial vehicle according to claim 2, wherein, The triangular bottom surface structure further includes three third beams, the first ends of the three third beams are commonly connected to the position where the center of gravity of the bottom surface structure is located, and the second ends of the three third beams are respectively connected to the three first connection positions.

4. The variable airfoil composite wing vertical takeoff and landing unmanned aerial vehicle according to claim 3, characterized in that, The lift structure includes: A first motor, the first motor being installed at the position where the center of gravity of the triangular bottom surface structure is located, and being used to output driving force; A clutch, the input shaft of the clutch being connected to the output shaft of the first motor; A universal joint, the input shaft of the universal joint being connected to the output shaft of the clutch; A dual-rotor structure, the input shaft of the rotating shaft of the dual-rotor structure being connected to the output shaft of the universal joint, and two sets of rotors distributed vertically being installed on the rotating shaft, and the two sets of rotors rotate in opposite directions; Wherein, the output shaft direction of the universal joint is adjustable.

5. The variable airfoil composite wing vertical take-off and landing unmanned aerial vehicle according to claim 4, characterized in that, The thrust structure includes: Three second motors, the three second motors being evenly distributed around the first motor; Three connecting shafts, each connecting shaft being correspondingly connected to the output shaft of one of the second motors; each connecting shaft is correspondingly parallel to each of the third beams; Three propellers, each propeller being correspondingly sleeved on each connecting shaft.

6. The variable airfoil composite wing vertical takeoff and landing unmanned aerial vehicle according to claim 2, wherein, The retractable horizontal wings include: A transverse shaft, the transverse shaft being symmetrically provided at one of the first connection positions; Two rotating pin shafts, the two rotating pin shafts being respectively provided at both ends of the transverse shaft; Two sets of triangular wing surfaces, the two sets of triangular wing surfaces being respectively provided on both sides of the two first beams that form the first connection position; the top end of each set of triangular wing surfaces is correspondingly connected to one of the rotating pin shafts; each set of triangular wing surfaces includes a triangular skin and a plurality of bone beams for supporting the skin; the first ends of the plurality of bone beams are sequentially connected to one of the rotating pin shafts, so that the plurality of bone beams rotate around the rotating pin shaft in the plane where the triangular bottom surface structure is located and unfold in a fan shape; Two sets of push rod drive structures, each set of the push rod drive structures is connected to a set of the triangular wing surfaces and is used to control the deployment and retraction of the corresponding triangular wing surfaces.

7. The variable airfoil composite wing vertical take-off and landing unmanned aerial vehicle according to claim 6, wherein, The push rod drive structure includes: A first push rod mechanism, the push rod of the first push rod mechanism is connected to the outermost bone beam of the corresponding triangular wing surface. When the first push rod mechanism extends, the corresponding triangular wing surface deploys and the triangular wing surface is coplanar with the triangular bottom surface structure. When the first push rod mechanism retracts, the corresponding triangular wing surface retracts to one side of the corresponding first beam. A second push rod mechanism, the push rod of the second push rod mechanism is connected to the second end of the innermost bone beam of the corresponding triangular wing surface. When the push rod of the second push rod mechanism extends, the push rod of the second push rod mechanism inclines downward to the triangular bottom surface structure, so that the corresponding triangular wing surface faces the wind.

8. The variable airfoil composite wing vertical take-off and landing unmanned aerial vehicle according to claim 2, characterized in that, The length of the second beam is less than or equal to the length of the first beam.

9. The variable airfoil composite wing vertical takeoff and landing unmanned aerial vehicle according to claim 4, characterized in that The length of the rotating shaft is 1 / 5 to 1 / 3 times the distance from the center of gravity to the second connection position. The diameter of the circle formed by the rotation trajectory of the rotor blade tip is 0.9 to 1.2 times the length of the first beam.

10. The variable airfoil composite wing vertical takeoff and landing unmanned aerial vehicle according to claim 5, characterized in that, The length of the connecting shaft is 1 / 5 to 1 / 3 times the distance from the center of gravity to the first connection position. The diameter of the circle formed by the rotation trajectory of the propeller blade tip is 1.5 to 2 times the length of the connecting shaft.

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