Vertical take-off and landing variant layout quad-rotor unmanned aerial vehicle and working method thereof

Abstract

The invention provides a vertical take-off and landing variant layout quad-rotor unmanned aerial vehicle and a working method thereof, and belongs to the technical field of aerodynamic layout design of aircrafts. The invention aims to meet the requirements of vertical take-off and landing and high-efficiency long-endurance flight at the same time. The unmanned aerial vehicle comprises a fuselage, a central wing box, variable sweepback wings, motors, empennages, rotating shafts and propellers, a central wing box and an empennage are arranged on the fuselage, the variable sweepback wings are connected with the central wing box through rotating shafts, the empennage is in an X shape, four motors are distributed on the empennage, and each motor is connected with a propeller; the propellers are defined as a first propeller, a second propeller, a third propeller and a fourth propeller clockwise, in the overlook direction, the first propeller and the third propeller rotate clockwise, and the second propeller and the fourth propeller rotate anticlockwise. By fusing the vertical take-off and landing advantages of the rotors and the low energy consumption characteristic of the fixed wings, the aircraft balances the resistance by using the lift force of the wings in the cruising stage, so that the power consumption of the rotor motors is greatly reduced, and the bottleneck of short flight time of the traditional rotors is broken through.

Description

Technical Field

[0001] The present invention relates to the technical field of aircraft aerodynamic layout design, and particularly to a vertical takeoff and landing variant layout quadrotor unmanned aircraft and its working method. Background Art

[0002] Rotorcraft and conventional fixed-wing aircraft are widely used in different fields due to their respective unique technical characteristics. Rotorcraft, relying on the significant advantage of vertical takeoff and landing, can flexibly take off and land in areas with limited space and complex terrain. However, its flight principle determines that whether in level flight or takeoff and landing, the weight of the aircraft must rely on the lift generated by the rotors to offset, which makes the rotor motors have to continuously operate at high power to maintain a stable flight altitude. The resulting high energy consumption problem leads to a generally short endurance time for rotorcraft, making it difficult to meet the requirements of long-time operations, and greatly restricting its application expansion in fields such as long-distance inspection and emergency rescue.

[0003] On the contrary, for conventional fixed-wing aircraft, according to the aerodynamic principle, its gravity is mainly balanced by the lift generated by the wings, and the power system only needs to overcome the air resistance far lower than the lift to maintain stable cruising. This relatively efficient energy utilization method gives fixed-wing aircraft the outstanding advantages of low energy consumption, long range, and long endurance. However, the characteristic of relying on a runway for takeoff and landing by sliding of conventional fixed-wing aircraft places high requirements on the takeoff and landing site, which needs to meet certain length, flatness, and openness, and it is difficult to achieve in complex terrain environments such as urban building-dense areas, mountainous areas, and water surfaces, resulting in obvious limitations in its application scenarios.

[0004] In summary, there is an urgent need to design an unmanned aircraft that can simultaneously meet the requirements of vertical takeoff and landing and efficient long-endurance flight. Summary of the Invention

[0005] A brief overview of the present invention is given below to provide a basic understanding of certain aspects of the present invention. It should be understood that this overview is not an exhaustive overview of the present invention. It is not intended to identify the key or important parts of the present invention, nor is it intended to limit the scope of the present invention. Its purpose is merely to present certain concepts in a simplified form as a prelude to the more detailed description to be discussed later.

[0006] In view of this, to simultaneously meet the requirements of vertical takeoff and landing and efficient long-endurance flight, the present invention provides a vertical takeoff and landing variant layout quadrotor unmanned aircraft and its working method.

[0007] Solution 1: A vertical takeoff and landing variant layout quadrotor unmanned aircraft, comprising a fuselage, a central wing box, variable-sweep wings, motors, a tail wing, a rotating shaft, and propellers;

[0008] The fuselage is provided with a central wing box and a tail wing. The variable-sweep wing is connected to the central wing box through a rotating shaft. The tail wing is in an X shape, and four motors are distributed on the X-shaped tail wing. Each motor is connected with a propeller.

[0009] The propellers are defined as the first propeller, the second propeller, the third propeller, and the fourth propeller in a clockwise order. In the top view direction, the first propeller and the third propeller rotate clockwise, and the second propeller and the fourth propeller rotate counterclockwise.

[0010] Further, the fuselage is a body of revolution, and the nose and the tail are blunt bodies.

[0011] Further, the central wing box and the variable-sweep wing adopt an airfoil with a flat lower wing surface.

[0012] Further, the tip chord length of the variable-sweep wing is less than the root chord length.

[0013] Further, the first propeller, the second propeller, the third propeller, and the fourth propeller are all two-blade propellers.

[0014] Solution 2: A working method of a vertical takeoff and landing variant layout four-rotor unmanned aircraft is realized as follows:

[0015] A. When the unmanned aircraft takes off and lands, the angle of attack is greater than the critical angle of attack, and the rotor control mode is adopted; the yaw attitude is controlled by the anti-torque of the first propeller, the second propeller, the third propeller, and the fourth propeller; the roll attitude is controlled by the lift difference brought by the differential speed control between the first propeller and the fourth propeller and the second propeller and the third propeller; the pitch attitude is controlled by the lift difference brought by the differential speed control between the first propeller and the second propeller and the third propeller and the fourth propeller.

[0016] B. When the unmanned aircraft is in level flight, the angle of attack is less than the critical angle of attack, and the fixed-wing control mode is adopted; the yaw attitude is controlled by the lift difference brought by the differential speed control between the first propeller and the fourth propeller and the second propeller and the third propeller; the roll attitude is controlled by the anti-torque of the first propeller, the second propeller, the third propeller, and the fourth propeller; the pitch attitude is controlled by the lift difference brought by the differential speed control between the first propeller and the second propeller and the third propeller and the fourth propeller.

[0017] Further, when the unmanned aircraft takes off and lands, the sweep angle of the wing is 90°; when the unmanned aircraft is in level flight, the sweep angle of the wing is 15° - 70°.

[0018] The present invention has the following beneficial effects compared with the prior art:

[0019] 1. The device of the present invention combines the advantages of vertical takeoff and landing of rotors with the low energy consumption characteristics of fixed wings, enabling the aircraft to utilize wing lift to balance drag during the cruise phase, significantly reducing the power consumption of rotor motors, extending the hovering time, and breaking through the bottleneck of short flight time of traditional rotors.

[0020] 2. The device of the present invention enables the power system to output as required in different stages by switching flight modes: relying on four rotors to provide instantaneous pulling force during takeoff and landing, and reducing power loss through the fixed-wing aerodynamic layout during cruise, achieving the maximum energy utilization efficiency.

[0021] 3. The device of the present invention combines the long flight time ability of fixed wings with the vertical takeoff and landing flexibility of rotors, getting rid of the dependence on the "special takeoff and landing site" of traditional fixed wings, and can achieve takeoff, landing and long-time operation in scenarios such as narrow spaces and complex terrains, expanding the applicable range of the aircraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings described herein are used to provide a further understanding of the present invention and form a part 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:

[0023] Figure 1 It is a schematic structural diagram of a vertical takeoff and landing variant layout four-rotor unmanned aircraft and its working method;

[0024] Figure 2 It is a top view during flight in fixed-wing mode;

[0025] Figure 3 It is for Figure 2 View A of;

[0026] Figure 4 It is for Figure 2 View B of rotated 90° counterclockwise;

[0027] Figure 5 It is a top view during flight in rotor mode.

[0028] In the figure: 1 - fuselage, 2 - central wing box, 3 - variable-sweep wing, 4 - motor, 5 - tail wing, 6 - rotating shaft, 7 - first propeller, 8 - second propeller, 9 - third propeller, 10 - fourth propeller. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] In order to make the technical solutions and advantages in the embodiments of the present invention clearer and more understandable, the following further details the exemplary embodiments of the present invention with reference to the drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than an exhaustive list of all embodiments. It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0030] Example 1, reference Figures 1-5 This embodiment will be described. A vertical takeoff and landing variant layout quadrotor unmanned aircraft includes a fuselage 1, a central wing box 2, a variable-sweep wing 3, motors 4, a tail 5, a rotating shaft 6, and propellers;

[0031] The central wing box 2 and the tail 5 are arranged on the fuselage 1. The variable-sweep wing 3 is connected to the central wing box 2 through the rotating shaft 6. The tail 5 is in an X shape. Four motors 4 are distributed on the X-shaped tail 5, and each motor 4 is connected to a propeller;

[0032] The propellers are defined as the first propeller 7, the second propeller 8, the third propeller 9, and the fourth propeller 10 in a clockwise order. In the top view direction, the first propeller 7 and the third propeller 9 rotate clockwise, and the second propeller 8 and the fourth propeller 10 rotate counterclockwise.

[0033] Further, the fuselage 1 is a body of revolution, and the nose and the tail are blunt bodies.

[0034] Further, the central wing box 2 and the variable-sweep wing 3 adopt an airfoil with a flat lower wing surface.

[0035] Further, the tip chord length of the variable-sweep wing 3 is less than the root chord length.

[0036] Further, the first propeller 7, the second propeller 8, the third propeller 9, and the fourth propeller 10 are all two-blade propellers.

[0037] Example 2, A working method of a vertical takeoff and landing variant layout quadrotor unmanned aircraft is as follows:

[0038] A. When the unmanned aircraft takes off and lands, the angle of attack is greater than the critical angle of attack, and the rotor control mode is adopted; the yaw attitude is controlled by the counter-torque of the first propeller 7, the second propeller 8, the third propeller 9, and the fourth propeller 10; the roll attitude is controlled by the lift difference brought by the differential speed control between the first propeller 7, the fourth propeller 10 and the second propeller 8, the third propeller 9; the pitch attitude is controlled by the lift difference brought by the differential speed control between the first propeller 7, the second propeller 8 and the third propeller 9, the fourth propeller 10;

[0039] B. When the unmanned aircraft is in level flight, the angle of attack is less than the critical angle of attack, and the fixed-wing control mode is adopted; the yaw attitude is controlled by the lift difference brought by the differential speed control between the first propeller 7, the fourth propeller 10 and the second propeller 8, the third propeller 9; the roll attitude is controlled by the counter-torque of the first propeller 7, the second propeller 8, the third propeller 9, and the fourth propeller 10; the pitch attitude is controlled by the lift difference brought by the differential speed control between the first propeller 7, the second propeller 8 and the third propeller 9, the fourth propeller 10.

[0040] Furthermore, when the drone takes off and lands, the sweep angle of the wing is 90°; when the drone is in level flight, the sweep angle of the wing is 15°-70°.

[0041] Through the present invention, the aircraft can utilize the wing lift to balance the drag during the cruise stage, greatly reducing the power consumption of the rotor motor, extending the hovering time, and breaking through the bottleneck of the short flight time of traditional rotors. At the same time, by switching the flight mode, the power system outputs as needed in different stages: relying on the four rotors to provide instantaneous pulling force during takeoff and landing, and reducing power loss through the fixed-wing aerodynamic layout during cruise, achieving the maximum energy utilization efficiency.

[0042] Through the present invention, the dependence on the "special takeoff and landing site" of the traditional fixed wing is eliminated, and takeoff, landing and long-term operation can be realized in scenarios such as narrow spaces and complex terrains, expanding the applicable range of the aircraft.

[0043] Although the present invention has been described based on a limited number of embodiments, those skilled in the art in this technical field will understand that other embodiments can be envisioned within the scope of the present invention thus described. In addition, it should be noted that the language used in this specification is mainly selected for readability and teaching purposes, rather than for the purpose of explaining or limiting the subject matter of the present invention. Therefore, many modifications and changes are obvious to those of ordinary skill in the art in this technical field without departing from the scope and spirit of the appended claims. For the scope of the present invention, the disclosure of the present invention is illustrative rather than restrictive, and the scope of the present invention is defined by the appended claims.

Claims

1. A vertical take-off and landing variant layout quadrotor unmanned aircraft, characterized in that, It includes a fuselage (1), a central wing box (2), a variable-sweep wing (3), motors (4), a tail (5), a rotating shaft (6) and propellers; The central wing box (2) and the tail (5) are arranged on the fuselage (1). The variable-sweep wing (3) is connected to the central wing box (2) through the rotating shaft (6). The tail (5) is in an X shape, and the four motors (4) are distributed on the X-shaped tail (5), and each motor (4) is connected with a propeller; The propellers are defined as the first propeller (7), the second propeller (8), the third propeller (9) and the fourth propeller (10) in clockwise order. In the top view direction, the first propeller (7) and the third propeller (9) rotate clockwise, and the second propeller (8) and the fourth propeller (10) rotate counterclockwise.

2. The vertical take-off and landing variant layout quadrotor unmanned aircraft according to claim 1, characterized in that, The fuselage (1) is a body of revolution, and the nose and the tail are blunt bodies.

3. The vertical takeoff and landing variant layout quadrotor unmanned aircraft according to claim 1, characterized in that The central wing box (2) and the variable-sweep wing (3) adopt an airfoil with a flat lower wing surface.

4. The vertical take-off and landing variant layout quadrotor unmanned aircraft according to claim 3, characterized in that, The chord length of the wing tip of the variable-sweep wing (3) is less than the chord length of the wing root.

5. The vertical take-off and landing variant layout quadrotor unmanned aircraft according to claim 1, characterized in that, The first propeller (7), the second propeller (8), the third propeller (9) and the fourth propeller (10) are all two-blade propellers.

6. A working method of the vertical take-off and landing variant layout quadrotor unmanned aircraft according to claim 1, characterized in that, The implementation process is as follows: A. When the unmanned aircraft takes off and lands, the angle of attack is greater than the critical angle of attack, and the rotor control mode is adopted; the yaw attitude is controlled by the anti-torque of the first propeller (7), the second propeller (8), the third propeller (9) and the fourth propeller (10); the roll attitude is controlled by the lift difference brought by the differential speed control between the first propeller (7), the fourth propeller (10) and the second propeller (8), the third propeller (9); the pitch attitude is controlled by the lift difference brought by the differential speed control between the first propeller (7), the second propeller (8) and the third propeller (9), the fourth propeller (10); B. When the unmanned aircraft is in level flight, the angle of attack is less than the critical angle of attack, and the fixed-wing control mode is adopted; the yaw attitude is controlled by the lift difference brought by the differential speed control between the first propeller (7), the fourth propeller (10) and the second propeller (8), the third propeller (9); the roll attitude is controlled by the anti-torque of the first propeller (7), the second propeller (8), the third propeller (9) and the fourth propeller (10); the pitch attitude is controlled by the lift difference brought by the differential speed control between the first propeller (7), the second propeller (8) and the third propeller (9), the fourth propeller (10).

7. The working method of a vertical takeoff and landing variant layout quadrotor UAV according to claim 6, characterized in that When the unmanned aircraft takes off and lands, the sweep angle of the wing is 90°; when the unmanned aircraft is in level flight, the sweep angle of the wing is 15° - 70°.

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