A micro air vehicle powered by a seed of a plant of the family Lauraceae

Abstract

This invention discloses a non-powered micro-aircraft modeled after the seeds of Dipterocarpaceae plants, belonging to the field of micro-aircraft technology. The micro-aircraft of this invention includes a payload bay and at least two seed fins. The roots of the at least two seed fins are evenly distributed circumferentially on the top of the payload bay. The at least two seed fins have identical shapes. Along the centerline of the seed fins in the spanwise direction, from the root to the tip, the fins are constructed in a continuous or discontinuous curved shape, first extending upwards along the central vertical axis of the payload bay, and then obliquely upwards away from the central vertical axis. This curved shape causes stable vortices to form when airflow passes over the upper surface of the seed fins, providing lift for the micro-aircraft and reducing its descent speed during descent, enabling longer flight time. Furthermore, this invention has a simple structure and is lightweight, making it suitable for applications such as airdrop deployment, environmental detection, and special operations.

Description

Technical Field

[0001] This invention belongs to the field of micro-aircraft technology, specifically relating to a non-powered micro-aircraft modeled after the seeds of Dipterocarpaceae plants. Background Technology

[0002] Unpowered micro-aircraft, due to their outstanding advantages such as not requiring a continuous energy supply, simple structure, low cost, and large-scale deployment, have shown broad application prospects in fields such as environmental monitoring, meteorological detection, ecological surveys, and aerial sensor deployment. In recent years, researchers have developed a series of micro-aircraft by mimicking the aerodynamic characteristics of plant seeds, hoping to achieve long-endurance and highly stable unpowered flight.

[0003] Among existing technologies, dandelion seed-inspired aircraft are among the earliest and most mature types of unpowered aircraft. These aircraft can achieve a slow descent. However, they suffer from inherent technical limitations: First, they require extremely low Reynolds numbers, necessitating very small dimensions, which severely restricts payload capacity, making it difficult to carry payloads such as sensors and communication modules with sufficient mass. Second, these aircraft rely on wind for drift, lack rotational motion during flight, exhibit poor self-stability, and their descent trajectory is significantly affected by airflow disturbances, resulting in highly random flight direction.

[0004] Another representative design is the bamboo-dragonfly-inspired rotorcraft. This type of aircraft utilizes lift generated by the flow attached to the rotor surface to achieve spin-based gliding, exhibiting a certain degree of attitude stability. However, its lift generation mechanism relies solely on the flow attached to the rotor surface, resulting in a low lift coefficient; furthermore, it is extremely sensitive to flow separation. Once surface flow separation occurs, lift drops rapidly, leading to a narrow effective operating range. Especially under complex weather conditions or when encountering crosswind interference, flow separation easily occurs on the rotor surface, causing a sudden drop in lift and attitude instability, making reliable flight difficult to guarantee.

[0005] In summary, existing unpowered micro-aircraft still have shortcomings in terms of payload capacity, flight stability, and adaptability to different operating conditions, making it difficult to meet the technical requirements of future special operations for aircraft with appropriate payload, stable control, and strong adaptability to different operating conditions. Therefore, developing an unpowered micro-aircraft that combines appropriate payload capacity, high stability, and wide adaptability to different operating conditions has significant research value and application prospects. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a non-powered micro-aircraft modeled after the seeds of Dipterocarpaceae plants. It has the advantages of low cost, moderate weight, high stability, and long flight time, making it suitable for future special operations.

[0007] This invention discloses a non-powered micro-aircraft modeled after the seeds of Dipterocarpaceae plants, comprising:

[0008] The payload compartment; and at least two fruit wings, the roots of which are evenly distributed circumferentially on the top of the payload compartment;

[0009] At least two fruit wings have the same shape;

[0010] Along the span of the fruit wing, the centerline of the fruit wing, from the root of the fruit wing to the tip of the fruit wing, is constructed to present a continuous or discontinuous curved shape that first extends upward along the central vertical axis of the payload compartment, and then extends obliquely upward away from the central vertical axis. The curved shape causes the airflow to form a stable vortex when it flows over the upper surface of the fruit wing, providing lift for the micro-aircraft.

[0011] Optionally, the fruit wings have a preset twist angle; and at least two of the fruit wings have the same twist angle direction.

[0012] Optionally, at the base of the fruit wing, the tangent along the extension direction of the center line of the fruit wing and the central vertical axis form a first tangent angle;

[0013] At the midpoint of the fruit wing centerline along the span direction, the tangent of the fruit wing centerline along the span direction and the central vertical axis form a second tangent angle.

[0014] At the tip of the fruit wing, the tangent along the spanning direction of the center line of the fruit wing and the central vertical axis form a third tangent angle;

[0015] The three tangent angles begin at the base of the fruit wing and increase continuously along the direction of extension.

[0016] Optionally, the range of the first tangent angle is -15° to 20°; the range of the second tangent angle is 20° to 80°; and the range of the third tangent angle is 80° to 180°.

[0017] Optionally, the cross-section of the fruit wing is configured as an upwardly convex or horizontal airfoil.

[0018] Optionally, the relative curvature of the fruit wing cross section is 0% to 30%, and the relative thickness is 1% to 20%.

[0019] Optionally, the chord length of the fruit wing gradually widens from the root of the fruit wing along the span direction towards the tip of the fruit wing, reaching its widest point at 0.5 to 0.9 times the span, and then gradually decreases to the tip of the fruit wing, with the aspect ratio of the fruit wing being 5 to 15.

[0020] Optionally, the payload compartment has a streamlined shape.

[0021] Optionally, the fruit wing and the load chamber are connected in the direction of airflow.

[0022] Optionally, the payload compartment includes an outer shell and internal electronic components.

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

[0024] (1) The aircraft of the present invention has a high flight Reynolds number, moderate size, certain load capacity, and can rotate during flight, with good flight stability.

[0025] (2) The aircraft of the present invention utilizes a special aerodynamic configuration to generate an attachment vortex on the upper surface of the fruit wing, thereby increasing lift and expanding the range of flight conditions. Even if a separation flow occurs above the fruit wing, lift can still be generated. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the embodiments will be briefly introduced below. The features and advantages of the present invention can be more clearly understood by referring to the accompanying drawings. The accompanying drawings are schematic and should not be construed as limiting the present invention in any way. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a front view of the micro-aircraft of the present invention;

[0028] Figure 2 This is a top view of the micro-aircraft of the present invention;

[0029] Figure 3 This is a front view of the micro-aircraft of the present invention;

[0030] Figure 4 This is a schematic diagram of the torsion angle of the micro-aircraft of the present invention;

[0031] Figure 5 This is a schematic diagram of the aerodynamic forces acting on the fruit wings of the micro-aircraft of the present invention before they begin to rotate during descent.

[0032] Figure 6 This is a schematic diagram of the aerodynamic forces acting on the fruit-wing of the micro-aircraft of the present invention during descent and rotation;

[0033] Figure 7 This is a schematic diagram of the first tangent angle of the micro-aircraft of the present invention;

[0034] Figure 8 This is a schematic diagram of the second tangent angle of the micro-aircraft of the present invention;

[0035] Figure 9This is a schematic diagram of the third tangent angle of the micro-aircraft of the present invention;

[0036] Figure 10 This is a schematic diagram of the suction zone above the fruit wing of the micro-aircraft of the present invention;

[0037] Figure 11 This is a schematic diagram of the attachment vortex above the fruit wing of the micro-aircraft of the present invention;

[0038] Figure 12 The simulation results show the attached vortices above the fruit wings of the micro-aircraft of this invention.

[0039] Explanation of reference numerals in the attached figures:

[0040] 1. Fruit wing; 2. Load chamber; 3. Cross section of the fruit wing; 4. Starting point of the fruit wing along its span; 5. First tangent angle; 6. Midpoint of the centerline of the fruit wing along its span; 7. Second tangent angle; 8. Ending point of the fruit wing along its span; 9. Third tangent angle; 10. Low-pressure area on the upper surface of the fruit wing; 11. Rotation direction of the fruit wing; 12. Attached vortices on the upper surface of the fruit wing. Detailed Implementation

[0041] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other.

[0042] A specific embodiment of the present invention, such as Figures 1-2 As shown, a non-powered micro-aircraft modeled after the seeds of Dipterocarpaceae plants is disclosed, comprising a payload compartment 2 and fruit-shaped wings 1. The payload compartment 2 consists of an outer shell and internal electronic components. At least two identical fruit-shaped wings 1 are provided, with the starting point 4 (i.e., the root of the fruit-shaped wing) along the span direction fixedly connected to the top of the payload compartment 2. Figure 7 As shown, the starting point 4 of the fruit wing along the span direction is connected to the load compartment 2 in the direction of the airflow.

[0043] In an optional embodiment, the centerline of the fruit wing 1 along its span direction, from the root to the tip, is configured to exhibit a continuous or discontinuous curved shape that first extends upward along the central vertical axis of the payload compartment 2, and then extends obliquely upward away from the central vertical axis. This curved shape causes stable vortices to form when airflow passes over the surface of the fruit wing, providing lift for the micro-aircraft.

[0044] Preferably, two fruit wings 1 are provided.

[0045] During operation, as the aircraft descends, the fruit wings 1, influenced by aerodynamics, cause the unpowered micro-aircraft, modeled after Dipterocarpus seeds, to rotate around the central vertical axis of the payload compartment 2. Under the combined effects of descent and rotation, the two fruit wings 1 generate upward lift due to relative airflow. Furthermore, vortices adhere above the fruit wings 1, creating suction on their upper surfaces, further increasing the aircraft's total upward lift and thus slowing its descent, thereby increasing its loiter time. Compared to conventional aircraft, this aircraft boasts advantages such as light weight, no power required, and low cost.

[0046] In an optional embodiment, the load chamber 2 has a symmetrical streamlined shape and an overall outline that is a smoothly transitioned curved surface structure. Preferably, the load chamber 2 is spherical or ellipsoidal.

[0047] Further, see Figure 5 The payload compartment 2 is divided into a lower spherical or lower ellipsoidal shape and an upper spherical or upper ellipsoidal shape. The overall outline of the lower spherical or lower ellipsoidal shape is larger than the overall outline of the upper spherical or upper ellipsoidal shape.

[0048] Through the above design, the present invention enables air to flow smoothly through the load chamber 2, reducing airflow separation and making the airflow continuing to flow upward through the fruit wing 1 more stable.

[0049] In an optional embodiment, the material of the fruit wing 1 is a carbon fiber composite elastic material.

[0050] Through the above design, the present invention enables the overall fruit wing 1 to have the advantages of being lightweight and low cost.

[0051] In an optional embodiment, see Figure 4 and Figure 10 The fruit wing 1 has a twist angle torsion angle The range is between 0° and 30°, preferably, the torsion angle is... The angle is 5°, and at least two fruit wings have the same shape, the same twist angle direction, and the same fruit wing rotation direction 11.

[0052] Understandably, the twist angle The angle between the projection of the chord of the fruit wing cross section onto the fruit wing cross section 3 and the intersection of the fruit wing cross section 3 and the horizontal plane.

[0053] Through the above design, the present invention enables the fruit wing 1 to generate a stable rotational force when air flows over it, so that the aircraft can rotate stably.

[0054] Before the fruit wings begin to rotate during descent, i.e., at the initial moment of descent, the aircraft is affected by airflow during its descent, such as... Figure 5 As shown, where, Representing the direction of airflow, the normal aerodynamic force acting on wing 1. Under the influence of the torsion angle, it has two components in two directions: a vertical aerodynamic component. and the aerodynamic components in the horizontal direction Horizontal aerodynamic components This caused the aircraft to begin rotating.

[0055] like Figure 6 As shown, after the aircraft begins to rotate, the relative velocity of the incoming flow to the wing 1 is... The local angle of attack of the fruit wing 1 is The lift force on wing 1 is Lift The component in the vertical direction is The vertical component of lift Under the influence of rotation, the aircraft can slow down its descent and maintain flight stability.

[0056] In an optional embodiment, the cross section 3 of the fruit wing is configured as an upwardly convex or horizontal airfoil, and its relative curvature and relative thickness are defined according to the relative curvature and relative thickness of the airfoil, with the relative curvature ranging from 0% to 30% and the relative thickness ranging from 1% to 20%.

[0057] Preferably, the relative curvature is 10% and the relative thickness is 3%.

[0058] Through the above design, the present invention enables the fruit wing 1 to generate lift during descent and rotation, thereby providing conditions for the fruit wing to induce attachment vortices, allowing the aircraft to obtain additional lift and extend its loiter time during descent.

[0059] In an optional embodiment, the chord length of the cross section 3 of the fruit wing is shorter at the root and gradually widens outward along the span (towards the wingtip), reaching its widest point at approximately 0.5 to 0.9 times the span, and then gradually decreases outward until the wingtip, with the aspect ratio of the fruit wing being in the range of 5 to 15.

[0060] Preferably, the chord length of the fruit wing (1) gradually widens outward from the root of the fruit wing along the span direction, reaching its widest point at 0.75 times the span, and then gradually decreases outward until the wingtip, and the aspect ratio of the fruit wing is 12.

[0061] Through the above design, the present invention enables the fruit wing 1 to achieve a higher lift-to-drag ratio during descent and rotation, and has a larger force-bearing area in the region where lift is mainly generated, thereby improving the lift of the aircraft.

[0062] In an optional embodiment, such as Figure 3 , Figure 7 , Figure 8 and Figure 9 As shown, the overall shape of the fruit wing 1, viewed from the front view, is an inwardly and upwardly convex arc-shaped outline. This arc-shaped outline is represented by the centerline of the fruit wing along its span direction. The centerline is a smooth curve with a continuous first derivative. Furthermore, at the midpoint 6 of the centerline along its span direction, the angle between the tangent to the centerline and the central vertical axis is the second tangent angle. The angle is within the range of 20° to 80°, preferably, the second tangent angle 7 is 45°; at the root of the fruit wing, that is, at the starting point 4 of the fruit wing along the extension direction, the angle between the tangent of the center line of the fruit wing along the extension direction and the central vertical axis is the first tangent angle. The angle is within the range of -15° to 20°, preferably, the first tangent angle 5 is -6°; at the end point 8 of the fruit wing along the spanning direction (i.e., the tip of the fruit wing), the angle between the tangent of the center line of the fruit wing along the spanning direction and the central vertical axis, i.e., the third tangent angle 9, is within the range of 80° to 180°. The angle is 120°, and the three tangent angles increase continuously from the root along the elongation direction.

[0063] It is understandable that, such as Figure 3 , Figure 7 , Figure 8 and Figure 9 As shown, the value of the tangent angle is the angle by which the tangent increases when it rotates away from the central vertical axis along the central vertical axis. From the perspective of the viewpoint, the value of the tangent angle is positive when rotating clockwise and negative when rotating counterclockwise.

[0064] Through the above design, the present invention, due to the continuous arc shape of the fruit wing 1 convex inward and upward, enables the leading edge vortex above the fruit wing 1 to stably adhere to the surface of the fruit wing 1 and maintain the vortex without breaking. Figure 11 The attached vortex 12 on the upper surface of the middle fruit wing and Figure 12 The simulation results show the attached vortices on the upper surface of the fruit wing, which generate a low-pressure region 10, i.e., a suction region, on the upper surface of the fruit wing 1. Figure 10 As shown, this allows the fruit wing 1 to generate additional lift and expand the applicable operating conditions, without fear of flow separation, thus extending the aircraft's loiter time.

[0065] All the above-mentioned optional technical solutions can be combined in any way to form optional embodiments of the present invention, and will not be described in detail here.

[0066] In the description of this invention, it should be understood that if terms such as "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0067] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order and method of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0068] It should be understood that the foregoing only illustrates some embodiments, and changes, modifications, additions, and / or variations can be made without departing from the scope and spirit of the disclosed embodiments. These embodiments are illustrative and not restrictive. Furthermore, the described embodiments relate to those currently considered most practical and preferred, and should be understood as not being limited to the disclosed embodiments, but rather intended to cover different modifications and equivalent arrangements included within the spirit and scope of those embodiments. Moreover, the various embodiments described above can be used in conjunction with other embodiments; for example, an aspect of one embodiment can be combined with an aspect of another embodiment to achieve yet another embodiment. Additionally, individual features or components of any given component can constitute another embodiment.

[0069] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A non-powered micro air vehicle that mimics the seed of a Dipterocarp plant, characterized by, include: The load chamber (2); and at least two fruit wings (1), the root of the fruit wings (1) being circumferentially distributed on the top of the load chamber (2); At least two fruit wings (1) have the same shape; Along the span direction of the fruit wing (1), the centerline of the fruit wing, from the root of the fruit wing to the tip of the fruit wing, is constructed to present a continuous or discontinuous curved shape that first extends upward along the central vertical axis of the payload compartment (2) and then extends obliquely upward away from the central vertical axis. The curved shape causes the airflow to form a stable vortex when it flows over the upper surface of the fruit wing, providing lift for the micro aircraft. At the base of the fruit wing, the tangent to the center line of the fruit wing along the extension direction and the central vertical axis form the first tangent angle; At the midpoint (6) of the center line of the fruit wing along the spanning direction, the tangent of the center line of the fruit wing along the spanning direction and the central vertical axis form a second tangent angle; At the tip of the fruit wing, the tangent along the spanning direction of the center line of the fruit wing and the central vertical axis form a third tangent angle; The three tangent angles begin at the base of the fruit wing and increase continuously along the direction of extension.

2. The Myristicaceae seed-powered micro air vehicle of claim 1, wherein, The fruit wing (1) has a preset torsion angle; and at least two of the fruit wing (1) have the same torsion angle direction.

3. The unpowered micro-aircraft modeled after Dipterocarpaceae plant seeds according to claim 1, characterized in that, The range of the first tangent angle is -15° to 20°; the range of the second tangent angle is 20° to 80°; and the range of the third tangent angle is 80° to 180°.

4. The unpowered micro-aircraft modeled after Dipterocarpaceae plant seeds according to claim 1, characterized in that, The cross-section (3) of the fruit wing is an upwardly convex or horizontally wing-shaped configuration.

5. The unpowered micro-aircraft modeled after Dipterocarpaceae plant seeds according to claim 4, characterized in that, The relative curvature of the cross section (3) of the fruit wing is 0% to 30%, and the relative thickness is 1% to 20%.

6. The unpowered micro-aircraft modeled after Dipterocarpaceae plant seeds according to claim 1, characterized in that, The chord length of the fruit wing (1) gradually widens from the root of the fruit wing along the span direction to the tip of the fruit wing, and is widest at 0.5 to 0.9 times the span, and then gradually decreases to the tip of the fruit wing, and the aspect ratio of the fruit wing is 5 to 15.

7. The unpowered micro-aircraft modeled after Dipterocarpaceae plant seeds according to claim 1, characterized in that, The payload compartment (2) has a streamlined shape.

8. The unpowered micro-aircraft modeled after Dipterocarpaceae plant seeds according to claim 1, characterized in that, The fruit wing (1) and the load compartment (2) are connected in the direction of airflow.

9. The unpowered micro-aircraft modeled after Dipterocarpaceae plant seeds according to claim 1, characterized in that, The payload compartment (2) includes an outer shell and internal electronic components.

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