Wing of bionic flapping-wing aircraft capable of inhabiting perpendicular to wall surface

Abstract

The invention discloses a wing of a bionic flapping-wing aircraft capable of inhabiting in a manner of being perpendicular to a wall surface. The wing comprises a connecting component, a supporting framework and a wing membrane, the connecting component is of a four-fork branch supporting arm structure of a forked structure, the tail end of each supporting arm is provided with a long hole used for fixing the supporting framework, and the center boss is provided with a rudder arm connecting hole used for being connected with a driving component. The supporting framework comprises a main force bearing beam, sub-components distributed in a radial mode, transverse fixing wing ribs and rear wing supporting wing ribs distributed in an annular mode. The wing film is adhered to the surface of the supporting framework to form a front wing area and a rear wing area of the wing; wherein the outer contour of the front wing area is constructed to have the curvature radius which is continuously reduced from the wing root to the wing tip, and a variable curvature radius layout is formed; and the hip angle curvature radius of the rear wing area is 50mm. Through structural innovation, the aerodynamic efficiency, the structural stability and the collaboration with inhabiting components of the wing are effectively improved, and the wing is particularly suitable for a bionic flapping-wing aircraft needing to inhabit on a vertical wall surface.

Description

Technical Field

[0001] This invention relates to the field of micro bionic flapping-wing aircraft, and more particularly to a wing of a bionic flapping-wing aircraft capable of perching on a vertical wall. Background Technology

[0002] Miniature biomimetic flapping-wing aircraft, such as butterfly-inspired aircraft, have shown great application potential in military reconnaissance, disaster relief, and facility inspection due to their low noise, high maneuverability, and good stealth capabilities. Achieving stable perching on vertical walls could greatly extend their mission capabilities and endurance. However, existing biomimetic flapping-wing aircraft face core technological challenges in vertical wall perching: First, when the aircraft approaches the wall, complex aerodynamic effects (such as ground effect and vortex interference) can lead to lift fluctuations and attitude instability; second, for successful perching, the wings need to provide sufficient lift under low-frequency flapping and possess good structural strength to cushion landing impact; furthermore, the force transmission efficiency and stability of the wing-body connection structure directly affect the reliability of perching. Most current designs have failed to effectively solve these problems, exhibiting issues such as insufficient lift under low-frequency flapping, large airflow disturbances near the wall, and low perching success rates.

[0003] Therefore, there is an urgent need for an innovative wing design that can optimize aerodynamic performance, enhance structural stability, and achieve effective synergy with the hull structure. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a wing for a biomimetic flapping-wing aircraft that can perch on a vertical wall, which can effectively improve the aerodynamic efficiency, structural stability and control reliability of the aircraft during the vertical wall perch process.

[0005] The wing of a biomimetic flapping-wing aircraft capable of perching on a vertical wall, as described in this invention, includes connecting components, a supporting frame, and a wing membrane; The biomimetic connecting component adopts a four-pronged branch arm structure, with elongated holes at the ends of each arm for fixing the support frame, and a rudder arm connecting hole at the center boss for connecting the drive component. The supporting frame includes a main load-bearing beam, radially distributed sub-components, transversely fixed wing ribs, and annular rear wing support wing ribs. The layout is optimized through finite element analysis. The main load-bearing beam extends along the leading edge of the forewing. The starting points of the radially distributed sub-components are evenly distributed on the leading edge of the forewing and radiate evenly from the outer edge of the forewing. The transversely fixed wing ribs and the radially distributed sub-components form a four-node connection structure. The wing membrane is bonded to the surface of the supporting frame to form the forewing and rearwing regions of the wing, and the aspect ratio of the entire wing is 1.35; wherein, the outer contour of the forewing region is constructed to have a continuously decreasing radius of curvature from the wing root to the wingtip, forming a variable radius of curvature layout; the rearwing region has a hip angle radius of curvature of 50mm.

[0006] Further optimization is achieved by constructing the outline of the forewing region as follows: the angle between its root leading edge and the horizontal direction is 60°±0.5°, and its wingtip forward sweep angle is 30°±0.5°.

[0007] Further optimization involves using 3D-printed resin material for the connecting components, with an elastic modulus of 2.1 GPa ± 0.2 GPa. The four-pronged branch support structure includes a main load-bearing support extending along the leading edge of the forewing, a transverse fixing support extending along the leading edge of the forewing about 1 / 3 of the way from the wingtip, and a hindwing support. The hindwing support is a forked structure, forming an inner support and an outer support, which extend along the leading and trailing edges of the hindwing, respectively.

[0008] Further optimization involves the following support frame: the main load-bearing beam is made of carbon fiber rod with a diameter of 1.0 mm, the front end of which is fixed in the elongated hole of the main load-bearing arm and extends from the root of the forewing to the wingtip; the radial sub-components include a first wing rib, a second wing rib, a third wing rib, and a fourth wing rib, all made of carbon fiber rod with a diameter of 0.8 mm. The front ends of all wing ribs are fixed to the main load-bearing beam. The first wing rib extends to the wingtip at an angle of -5° with the horizontal direction, forming the first support line; the second, third, and fourth wing ribs are distributed at equal arithmetic angles of 10° with the horizontal direction, with their starting points equidistantly distributed below the first wing rib and extending to the outer edge of the forewing; the fourth wing rib extends to the inflection point of the side edge; the transverse fixing wing rib is made of carbon fiber rod with a diameter of 1.6 mm, one end of which is inserted into the elongated hole of the transverse fixing arm, connecting all the radial sub-components, extending along the direction of 1 / 3 of the leading edge chord length, and forming an intersection point with the radial sub-components to construct the wing surface aerodynamic support network.

[0009] Further optimization includes the following intersection points: the first intersection point is formed by intersecting with the first rib; the second, third, and fourth intersection points are formed by intersecting with the second, third, and fourth ribs at decreasing angles of 10°; and the wing surface aerodynamic support network is constructed through four-point spatial anchoring to ensure that the wing surface maintains its natural aspect ratio during flight.

[0010] Further optimization involves using a carbon fiber rod with a diameter of 1.0 mm for the rear wing support rib. One end is fixed in the elongated hole of the inner support arm, and the other end is fixed in the elongated hole of the outer support arm, with the outline conforming to the wing membrane of the rear wing area.

[0011] Further optimization involves the following: in the biomimetic connecting component, the length of each arm's long hole is 5-7 times the diameter of the corresponding carbon fiber rod, and the axis is consistent with the installation direction; the diameter of the rudder arm connecting hole is 2.0mm ± 0.1mm, and the axis is perpendicular to the flapping wing's motion plane.

[0012] Further optimization involves using polyester film material for the wing membrane, and bonding it to the supporting frame with B7000 adhesive.

[0013] Further optimization involves connecting the carbon fiber rods in the support frame using D5604B light-cured adhesive.

[0014] The present invention also discloses a biomimetic flapping-wing aircraft, comprising the wings of the aforementioned biomimetic flapping-wing aircraft capable of perching on a vertical wall.

[0015] 1. Improved aerodynamic performance: The variable curvature radius design of the leading edge improves the leading edge vortex separation characteristics during flapping, enhances the lift generation efficiency under low-frequency flapping, and strengthens flight stability.

[0016] 2. Structural stability and efficiency: The synergistic design of the biomimetic integrated connecting components and the radial support frame enables efficient load transfer and distribution, improves the structural stiffness and fatigue life of the wing, and is also conducive to lightweighting.

[0017] 3. Habitat reliability: The optimized wing structure provides the aircraft with higher load capacity, stable flight attitude and sufficient cushioning capacity. When combined with dedicated habitat devices (such as cushioned landing devices), it can significantly improve the success rate of vertical wall habitat.

[0018] 4. Manufacturability and maintainability: The structure is simple, which facilitates the manufacturing, assembly, and subsequent maintenance and replacement of the wings. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a cross-sectional view of the connecting component of the present invention; Figure 3 This is a perspective view of the connecting component of the present invention; Figure 4 This is a schematic diagram of the wing membrane of the present invention; Figure 5 This is a schematic diagram of the structure of a biomimetic flapping-wing aircraft; Figure 6 It is an isovortex surface plot of the simulation with variable sweep angle; Figure 7 It is a diagram of the aerodynamic characteristics simulated with a variable sweep angle; Figure 8 It is a wind tunnel experiment with a variable sweep angle, showing the lift and overturning moment curves. In the figure, 1-connecting component, 2-wing membrane, 3-elongated hole, 4-rudder arm connecting hole, 5-main load-bearing arm, 6-lateral fixed arm, 7-inner hindwing arm, 8-outer hindwing arm, 9-main load-bearing beam, 10-first wing rib, 11-second wing rib, 12-third wing rib, 13-fourth wing rib, 14-lateral fixed wing rib, 15-hindwing support wing rib. Detailed Implementation

[0020] The present invention will now be described in further detail with reference to the accompanying drawings: Example

[0021] like Figure 1-4 As shown, the wings of a biomimetic flapping-wing aircraft capable of perching on a vertical wall are divided into a left wing and a right wing. The left and right wings have the same structure, including a connecting component 1, a supporting frame and a wing membrane 2. The connecting component 1 adopts a four-forked branch arm structure. Each arm end is provided with an elongated hole 3 for fixing the support frame. The elongated hole is close to the plane that is in contact with the wing membrane to ensure that the wing membrane is in the same plane after it is fixed. The central boss is provided with a rudder arm connecting hole 4 for connecting the drive component. The supporting frame includes a main load-bearing beam 9, radially distributed sub-components, transverse fixed wing ribs 14, and a ring-shaped rear wing support wing rib 15. The layout is optimized through finite element analysis. The main load-bearing beam extends along the wingspan direction. The starting points of the radial sub-components are evenly distributed on the leading edge of the forewing and evenly diverge from the outer edge of the forewing. The transverse fixed wing ribs and the radial sub-components form a four-node connection structure. The wing membrane 2 is bonded to the surface of the supporting frame to form the forewing and rearwing regions of the wing, and the aspect ratio of the entire wing is 1.35. The outer contour of the forewing region is constructed to have a radius of curvature ρ (unit: mm) that decreases continuously from the wing root to the wingtip, forming a variable radius of curvature layout (e.g. Figure 3 The leading edge is designed with a variable curvature radius, which improves the leading edge vortex separation characteristics during flapping, enhances the lift generation efficiency under low-frequency flapping, and strengthens flight stability; the radius of curvature of the anal angle in the hindwing region is 50mm.

[0022] In this embodiment, further optimization is achieved by constructing the outline of the forewing region as follows: the angle between its root leading edge and the horizontal direction is 60°±0.5°, and its wingtip forward sweep angle is 30°±0.5°.

[0023] In this embodiment, further optimization is achieved by using 3D printed resin material to make the connecting component 1, which has a four-pronged branch arm structure with an elastic modulus of 2.1 GPa ± 0.2 GPa. The four-pronged branch arm structure includes a main load-bearing arm 5 extending forward along the aircraft, a transverse fixed arm 6 extending about 1 / 3 of the way along the leading edge of the forewing near the wingtip, and a rearwing arm. The rearwing arm has a forked structure, forming an inner rearwing arm 7 and an inner rearwing arm 8, which correspond to the leading and trailing edges of the rearwing, respectively.

[0024] In this embodiment, further optimization is achieved. The main load-bearing beam 8 supporting the frame is made of carbon fiber rod with a diameter of 1.0 mm. The front end is fixed in the elongated hole of the main load-bearing arm and extends from the root of the forewing to the wingtip. The radial sub-components include a first wing rib 9, a second wing rib 10, a third wing rib 11, and a fourth wing rib 12, all made of carbon fiber rod with a diameter of 0.8 mm. The front ends of all wing ribs are fixed to the main load-bearing beam. The first wing rib extends to the wingtip at an angle of -5° with the horizontal direction, forming the first support line. The second, third, and fourth wing ribs are all distributed at equal arithmetic angles of 10° with the horizontal direction. Their starting points are equidistantly distributed below the first wing rib and extend to the outer edge of the forewing. The fourth wing rib extends to the inflection point of the side edge. The transverse fixing wing rib 13 is made of carbon fiber rod with a diameter of 1.6 mm. One end is inserted into the elongated hole of the transverse fixing arm 6, connecting all the radial sub-components. It extends along the direction of 1 / 3 of the leading edge chord length and forms an intersection point with the radial sub-components, constructing an aerodynamic support network for the wing surface.

[0025] In this embodiment, the intersection points of the lateral fixed ribs include: intersecting with the first rib to form a first intersection point, and intersecting with the second, third, and fourth ribs in descending order of 10° to form a second, third, and fourth intersection point. The wing surface aerodynamic support network is constructed through four-point spatial anchoring to ensure that the wing surface maintains its natural aspect ratio during flight.

[0026] Without increasing the overall weight, a lightweight carbon fiber skeleton structure was designed using topology optimization algorithms to maintain a balance between high stiffness and low mass in the wing surface during flapping. The skeleton design needs to consider the coupled response of flapping frequency and wing deformation to ensure that the wing surface maintains its morphological integrity during flapping motion, thereby improving lift efficiency. The distribution and density of the skeleton were optimized using finite element analysis to give it good structural stiffness and flapping compliance, adapting to the complex airflow environment near the vertical wall.

[0027] In this embodiment, further optimization is achieved by using a carbon fiber rod with a diameter of 1.0 mm for the rear wing support rib. One end is fixed in the elongated hole of the inner support arm, and the other end is fixed in the elongated hole of the outer support arm, with the contour conforming to the wing membrane of the rear wing area.

[0028] In this embodiment, further optimization is achieved by having the length of each arm's long hole in the connecting component be 5-7 times the diameter of the corresponding carbon fiber rod, with the axis aligned with the installation direction; the diameter of the rudder arm connecting hole is 2.0mm ± 0.1mm, with the axis perpendicular to the flapping wing's motion plane.

[0029] In this embodiment, further optimization is achieved by using polyester film material for the wing membrane and bonding it to the supporting frame with B7000 adhesive.

[0030] In this embodiment, further optimization is achieved by using D5604B light-cured adhesive to connect the carbon fiber rods in the support frame.

[0031] During assembly, the wing membrane 2 and connecting member 1 are first roughly positioned. Then, each carbon fiber rod is installed and glued to the corresponding position on the wing membrane and connecting member (such as inside the elongated hole 3) according to the design layout. Finally, overall adjustment and reinforcement are performed. The wing structure of this invention, through the multi-branch design of the connecting members and the radial shape of the carbon fiber skeleton, achieves a unified approach of precise aerodynamic shape control, minimal structural weight, and optimized mechanical performance. It is particularly suitable for micro biomimetic flapping-wing aircraft with vertical wall-dwelling capability that require high maneuverability and high load capacity. Example

[0032] like Figure 5 As shown, a biomimetic flapping-wing aircraft includes the wings of a biomimetic flapping-wing aircraft capable of perching on a vertical wall, as described in Example 1. Example

[0033] In this invention, such as Figure 6 As shown, the visualization of isovorticity (vorticity isosurface) from a comparative experiment with varying sweep angles demonstrates the flow field evolution under different sweep angle configurations within a complete flapping cycle: the horizontal axis represents the normalized time (t / T) of the flapping cycle, covering the continuous process from the starting point (t / T=0) to the ending point (t / T=1), corresponding to the phases of wing flapping down and up; the vertical axis compares different sweep angle designs, highlighting the differences in gradient angle of attack layouts. Vorticity values ​​are represented by color gradients or contour lines, with red / warm areas typically corresponding to high vorticity regions (such as leading-edge vortices LEV), and blue / cool areas corresponding to low vorticity regions. The figure clearly shows the formation, development, and dissipation processes of the vortex core. Combined with... Figure 6 As shown, the relationship between simulation variables (sweep angle 0 to 40°) and physical quantities (lift, drag) is analyzed: Through comparative experiments with gradient sweep angles, the advantages of sweep angles (20° to 30°) in improving the aerodynamic efficiency of low-frequency flapping were observed. Specifically, the vortex residence time is prolonged. Under a certain sweep angle configuration, the leading-edge vortex (LEV) maintains a more stable shape during the flapping cycle, and the vortex core breakup is delayed (compared to other angles). This is directly related to the lift generation mechanism. Vorticity is a physical quantity that measures the intensity of fluid rotation. High vorticity residence means a more sustained low-pressure region, thereby enhancing lift. The figure shows that at the midpoint of the cycle (e.g., t / T=0.5), the vorticity distribution is more uniform with sweep angles of 20° and 30°, avoiding local flow separation. This verifies that a certain sweep angle can optimize the spanwise flow field.

[0034] A prototype was then built, and the forward sweep angle parameters were refined (increasing by 5° every 5° from 20° to 35°) before wind tunnel testing was conducted.

[0035] like Figure 8 As shown in the wind tunnel test lift and overturning moment curves with varying sweep angles, the 30° sweep angle design can still maintain a strong vortex structure at low frequencies (1.72Hz to 3Hz). Averaging the results, it can be seen that the average lift coefficient of a 30° sweep angle is increased by 11% (compared to 20°) during low-frequency flapping, while the overturning moment is at an intermediate level. The overturning moment is a key parameter for adjusting the pitch attitude of an aircraft; both excessively large and small pitch moments will increase the difficulty of attitude adjustment.

[0036] Combination Figure 6 , Figure 7 , Figure 8 As shown, these elements together constitute the core experimental evidence for verifying aerodynamic performance. Visualized images and intuitive data curves directly demonstrate the significant advantages of the forward-swept angle design (30°) of this invention in improving low-frequency flapping aerodynamic efficiency, solving the problem of insufficient lift during low-frequency flapping in traditional designs. This is crucial for vertical wall occupancy, as occupancy requires precise low-speed control. The forward-swept angle effectively delays boundary layer separation, increases the lift coefficient at low Reynolds numbers, and enhances the dynamic lift performance of the wing surface during the flapping phase. Combined with wind tunnel experiments verifying aerodynamic efficiency, the wing developed in this invention enables the aircraft to maintain a stable aerodynamic response when approaching a wall, reducing lift attenuation caused by near-wall effects.

[0037] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements can be made without departing from the principle of the present invention, and these improvements should also be considered within the scope of protection of the present invention.

Claims

1. A wing of a biomimetic flapping-wing aircraft capable of perching on a vertical wall, characterized in that, Includes connecting components, supporting frame, and wing membrane; The connecting component adopts a four-branched support arm structure with a bifurcated configuration. Each support arm has an elongated hole at its end for fixing the support frame, ensuring that the wing membrane is bonded on the same plane. The central boss has a rudder arm connection hole for connecting the drive component. The supporting frame includes a main load-bearing beam, radially distributed sub-components, transverse fixed wing ribs, and a ring-shaped rear wing support wing rib. The layout is optimized through finite element analysis. The main load-bearing beam extends along the leading edge of the forewing, the starting points of the radial sub-components are evenly distributed on the leading edge of the forewing and radiate evenly from the outer edge of the forewing, and the transverse fixed wing ribs and radial sub-components form a four-node connection structure. The wing membrane is bonded to the surface of the supporting frame to form the forewing and rearwing regions of the wing, and the aspect ratio of the entire wing is 1.35; wherein, the outer contour of the forewing region is constructed to have a continuously decreasing radius of curvature from the wing root to the wingtip, forming a variable radius of curvature layout; the rearwing region has a hip angle radius of curvature of 50mm.

2. The wing of a biomimetic flapping-wing aircraft capable of perching on a vertical wall, as described in claim 1, is characterized in that... The outline of the forewing region is constructed such that the angle between its root leading edge and the horizontal direction is 60°±0.5°, and its wingtip forward sweep angle is 30°±0.5°.

3. The wing of a biomimetic flapping-wing aircraft capable of perching on a vertical wall, as described in claim 2, is characterized in that... The connecting component is made of 3D printed resin material with an elastic modulus of 2.1GPa±0.2GPa; the four-pronged branch support structure includes a main load-bearing support extending along the leading edge of the forewing, a transverse fixing support extending along the direction of the leading edge of the forewing near the wingtip 1 / 3, and a hindwing support, wherein the hindwing support is a forked structure, forming an inner support and an outer support, which are respectively along the leading and trailing edges of the hindwing.

4. The wing of a biomimetic flapping-wing aircraft capable of perching on a vertical wall, as described in claim 3, is characterized in that... In the supporting frame, the main load-bearing beam is made of carbon fiber rod with a diameter of 1.0 mm. The front end is fixed in the elongated hole of the main load-bearing arm and extends from the root of the forewing to the wingtip. The radial sub-components include a first wing rib, a second wing rib, a third wing rib, and a fourth wing rib, all made of carbon fiber rod with a diameter of 0.8 mm. The front ends of all wing ribs are fixed to the main load-bearing beam. The first wing rib extends to the wingtip at an angle of -5° with the horizontal direction, forming the first support line. The second, third, and fourth wing ribs are all distributed at equal arithmetic angles of 10° with the horizontal direction. The starting points are equidistantly distributed below the first wing rib and extend to the outer edge of the forewing. The fourth wing rib extends to the inflection point of the side edge. The transverse fixed wing rib is made of carbon fiber rod with a diameter of 1.6 mm. One end is fixed in the elongated hole of the transverse fixed arm and connects all the radial sub-components. It extends along the direction of 1 / 3 of the leading edge chord length and forms an intersection point with the radial sub-components to construct the aerodynamic support network of the wing surface.

5. The wing of a biomimetic flapping-wing aircraft capable of perching on a vertical wall, as described in claim 4, is characterized in that... The intersection points of the lateral fixed ribs include: a first intersection point formed by intersecting with the first rib; a second intersection point, a third intersection point, and a fourth intersection point formed by intersecting with the second, third, and fourth ribs at decreasing angles of 10°; and a wing surface aerodynamic support network constructed through four-point spatial anchoring to ensure that the wing surface remains naturally deployed during flight.

6. The wing of a biomimetic flapping-wing aircraft capable of perching on a vertical wall, as described in claim 5, is characterized in that... The rear wing support rib is made of carbon fiber rod with a diameter of 1.0 mm. One end is fixed in the long hole of the inner support arm, and the other end is fixed in the long hole of the outer support arm. The outline fits the wing membrane of the rear wing area.

7. The wing of a biomimetic flapping-wing aircraft capable of perching on a vertical wall, as described in claim 6, is characterized in that... In the biomimetic connecting component, the length of each arm's long hole is 5-7 times the diameter of the corresponding carbon fiber rod, and the axis is consistent with the installation direction; the diameter of the rudder arm connecting hole is 2.0mm±0.1mm, and the axis is perpendicular to the flapping wing's motion plane.

8. The wing of a biomimetic flapping-wing aircraft capable of perching on a vertical wall, as described in claim 7, is characterized in that... The wing membrane is made of polyester film material and is bonded to the supporting frame with B7000 adhesive.

9. The wing of a biomimetic flapping-wing aircraft capable of perching on a vertical wall, as described in claim 8, is characterized in that... The carbon fiber rods in the support frame are connected by D5604B light-cured adhesive.

10. A biomimetic flapping-wing aircraft, characterized in that, The wing of a biomimetic flapping-wing aircraft capable of perching on a vertical wall, as described in any one of claims 1-9.

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