An elongated flexible flapping wing

Abstract

A new type of flexible flapping wing, one end of the flexible flapping wing is a fixed end, the other end is a free end, the fixed end is connected with the aircraft, the connection position is between the leading edge of the flapping wing and the chordwise midpoint of the flapping wing, the flapping wing comprises a spanwise beam, a chordwise beam, a skin, the spanwise beam and the chordwise beam are connected through a rigid joint or a flexible joint to form a framework, the skin is wrapped outside the framework and is fixed on the framework by an adhesive or a rivet, the flexible joint comprises a four-bar mechanism and a limiting rod, the limiting rod is located on the spanwise beam, and the four-bar mechanism is located on the chordwise beam.

Description

Technical Field

[0001] This invention relates primarily to the field of flapping-wing aircraft, and more particularly to a slender, flexible flapping wing. Background Technology

[0002] Ornithoptering aircraft possess high aerodynamic efficiency and excellent maneuverability, providing both lift and thrust through flapping motion. Traditional ornithoptering aircraft mostly employ rigid wings, which have limited functionality due to insufficient flexibility and invariant shape. The developing intelligent, actively controlled morphing ornithoptering aircraft involves complex technologies such as intelligent materials and control, making its implementation highly challenging. Summary of the Invention

[0003] A slender flexible flapping wing, wherein one end of the flexible flapping wing is a fixed end and the other end is a free end. The fixed end is connected to the aircraft, and the connection point is located at any position between the leading edge of the flapping wing and the midpoint of the flapping wing in the chord direction. The flapping wing includes spanwise beams, chordwise beams, and skin. The spanwise beams and chordwise beams are connected by rigid joints and / or flexible joints to form a skeleton. The skin surrounds the skeleton and is fixed to the skeleton with adhesive or rivets. The flexible joints are hinged connections. The flexible joints also include a four-bar linkage mechanism and a limiting member. The four-bar linkage mechanism is located on the chordwise beam, and the limiting member is located on the spanwise beam.

[0004] The drive signal can be transmitted from the aircraft to the flapping wing through the connection point to control the flapping of the wing.

[0005] In some preferred embodiments, the aspect ratio of the elongated airfoil is greater than or equal to 3.

[0006] In some preferred embodiments, the number of spanwise beams is an odd number and greater than or equal to 3, preferably 5.

[0007] The spanwise beams serve as the main supporting structure, and the specific number of spanwise beams can be listed as follows: 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37, 39, 41, 43, 45, 47, 49, 51, 53, 55, 57, 59, 61, 63, 65, 67, 69, 71, 73, 75, 77, 79, 81, 83, 85, 87, 89, 91, 93, 95, 97, 99.

[0008] In some preferred embodiments, the span beams are parallel to each other, and the chord beams are parallel to each other.

[0009] In some preferred embodiments, the spanwise beam at the leading edge is connected to the chordwise beam by a rigid joint, and the spanwise beam at the trailing edge is connected to the chordwise beam by a rigid joint.

[0010] Flexible joints enable relative rotation between chordal and spanwise beams, with the range of rotation limited by limiting members.

[0011] In some preferred embodiments, the rigid joint is connected by one of the following methods: bolt and nut connection, welding, riveting, socket connection, snap-fit ​​connection, flange connection, and threaded connection.

[0012] The connection method of the rigid joint is not limited to the above connection forms.

[0013] In some preferred embodiments, the four-bar linkage includes link one, link two, link three, link four, hinge one, hinge two, hinge three, and hinge four. Link one and link two are connected by hinge one, link two and link three are connected by hinge two, link three and link four are connected by hinge three, and link four and link one are connected by hinge four.

[0014] In some preferred embodiments, the four-bar linkage is fixed to the chordal beam via hinge one and hinge four, and link one is connected to the chordal beam via hinge one and hinge four.

[0015] A second aspect of the present invention provides a four-bar linkage for the above-described elongated flexible flapping wing, the four-bar linkage comprising a first linkage, a second linkage, a third linkage, a fourth linkage, a first hinge, a second hinge, a third hinge, and a fourth hinge, wherein the first linkage and the second linkage are connected by the first hinge, the second linkage and the third linkage are connected by the second hinge, the third linkage and the fourth linkage are connected by the third hinge, and the fourth linkage and the first linkage are connected by the fourth hinge.

[0016] Working principle and beneficial effects: The flexible joint consists of a four-bar linkage and limiting links. By adjusting the four-bar linkage, the amplitude of the relative rotation between the spanwise and chordwise beams can be adjusted, thereby achieving different levels of flexibility. By setting the distribution of the flexible joints and adjusting their flexibility, the flexible flapping wing can flexibly adjust to the optimal structure under different operating loads to meet both aerodynamic and structural performance requirements.

[0017] like Figure 4 The four-bar linkage includes link one, link two, link three, link four, hinge one, hinge two, hinge three, and hinge four. Link one and link two are connected by hinge one, link two and link three are connected by hinge two, link three and link four are connected by hinge three, and link four and link one are connected by hinge four. The positions of hinge one and hinge four are fixed on the chordal beam, while the positions of hinge two and hinge three can be adjusted as needed.

[0018] By adjusting the positions of hinge two and hinge three, the rotation of the chord beam to both sides of the span beam can be restricted to different degrees.

[0019] Figure 4This is one of the general cases of a four-bar linkage. When the chordal beam rotates upward toward the longitudinal beam, the second link stops when it contacts the limiting link; when the chordal beam rotates downward toward the longitudinal beam, the third link stops when it contacts the limiting link.

[0020] Figure 5 and Figure 6 Two special cases are shown.

[0021] like Figure 5 As shown, when link two is parallel to the limiting member and located above link one, the rotation of the chordal beam to the upper side of the spanwise beam is completely restricted.

[0022] like Figure 6 As shown, when link two is parallel to the limiting member and located below the link, the rotation of the chord beam to the lower side of the spanwise beam is completely restricted.

[0023] Thus, by changing the connecting rods of different lengths and adjusting the position of the hinges, the rotation amplitude of the chordal beam to the spanning beam on one side can be limited. By changing the connecting rods of different lengths and adjusting the position of the hinges, the rotation amplitude of the chordal beam to the spanning beam on both sides can be limited, achieving the effect of the two sides having the same or different rotation amplitudes.

[0024] The slender, flexible flapping wing provided by this invention is a passively deformable wing structure. It not only solves the contradiction between load-bearing capacity and deformation in existing flapping wings, but also features a simple structure and is easy to maneuver. In the process of developing this invention, the inventors discovered that the flexible flapping wing provides sufficient load-bearing capacity and bending stiffness due to the spanwise beams as the main supporting structure; the presence of both flexible and rigid joints achieves a balance between rigidity and flexibility, while also providing necessary but not excessive passive deformation to meet aerodynamic performance requirements.

[0025] Furthermore, the inventors made an unexpected discovery: by setting up a four-bar linkage and limiting rods at the flexible joints, the chordal and spanwise beams of the flexible flapping wing can rotate within a certain range at the connection point, facilitating the adjustment of the flexibility of the joints at different positions according to different conditions. This achieves flapping wing deformation through "large rotation and small deformation," improving aerodynamic and structural efficiency. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of an elongated flexible flapping wing provided in some embodiments of the present invention;

[0027] Figure 2 This is a schematic diagram of an elongated flexible flapping wing provided in some embodiments of the present invention;

[0028] Figure 3 This is a schematic diagram of a flexible joint provided in some embodiments of the present invention;

[0029] Figure 4 This is a schematic diagram of a four-bar linkage provided in some embodiments of the present invention;

[0030] Figure 5 This is a schematic diagram of a four-bar linkage provided in some embodiments of the present invention;

[0031] Figure 6 This is a schematic diagram of a four-bar linkage provided in some embodiments of the present invention;

[0032] The markings in the diagram are as follows: 1 is the fixed end, 2 is the spanwise beam, 3 is the chordwise beam, 4 is the skin, 5 is the flexible joint, 6 is the rigid joint, 7 is the four-bar linkage, 8 is the hinge, 9 is the limiting member, 10 is the link one, 11 is the link two, 12 is the link three, 13 is the link four, 14 is the hinge one, 15 is the hinge two, 16 is the hinge three, and 17 is the hinge four. Detailed Implementation

[0033] In this invention, a slender airfoil refers to an airfoil with an aspect ratio greater than or equal to 3.

[0034] Example 1

[0035] like Figure 1 A slender flexible flapping wing, wherein one end of the flexible flapping wing is a fixed end 1 and the other end is a free end. The fixed end is connected to the aircraft, and the connection point is located at any position between the leading edge of the flapping wing and the midpoint of the flapping wing in the chord direction. The flapping wing includes a spanwise beam 2, a chord beam 3, and a skin 4. The spanwise beam and the chord beam are connected by a rigid joint 6 and a flexible joint 5 to form a skeleton. The skin surrounds the skeleton and is fixed to the skeleton with adhesive. The flexible joint is connected by a hinge 8. The flexible joint also includes a four-bar linkage 7 and a limiting member 9. The four-bar linkage is located on the chord beam, and the limiting member is located on the spanwise beam.

[0036] The number of spanwise beams is 3. The first spanwise beam is the leading edge of the flapping wing, and the third spanwise beam is the trailing edge of the flapping wing.

[0037] The span beams are parallel to each other, and the chord beams are parallel to each other.

[0038] The spanwise beam at the leading edge is connected to the chordwise beam via a rigid joint, and the spanwise beam at the trailing edge is also connected to the chordwise beam via a rigid joint. The second spanwise beam is connected to the chordwise beam via a flexible joint.

[0039] The rigid joint is connected by bolts and nuts.

[0040] like Figure 4The four-bar linkage includes link 10, link 21, link 312, link 413, hinge 14, hinge 215, hinge 316, and hinge 417. Link 1 and link 2 are connected by hinge 1, link 2 and link 3 are connected by hinge 2, link 3 and link 4 are connected by hinge 3, and link 4 and link 1 are connected by hinge 4.

[0041] The four-bar linkage is fixed to the chordal beam via hinge one and hinge four, and link one is rotatably connected to the chordal beam via hinge one and hinge four.

[0042] The position of the four-bar linkage at the flexible joint is as follows: Figure 4 Links 2 and 4 are located on both sides of link 1, respectively, limiting the rotation amplitude of the chord beam to both sides of the spanwise beam, so that the chord beam and spanwise beam of the flexible flapping wing have a bidirectional rotational effect at the connection point, and the rotation amplitude can be adjusted.

[0043] Example 2

[0044] like Figure 1 A slender flexible flapping wing, wherein one end of the flexible flapping wing is a fixed end 1 and the other end is a free end. The fixed end is connected to the aircraft, and the connection point is located at any position between the leading edge of the flapping wing and the midpoint of the flapping wing in the chord direction. The flapping wing includes a spanwise beam 2, a chord beam 3, and a skin 4. The spanwise beam and the chord beam are connected by a rigid joint 6 and a flexible joint 5 to form a skeleton. The skin surrounds the skeleton and is fixed to the skeleton with rivets. The flexible joint is connected by a hinge 8. The flexible joint also includes a four-bar linkage 7 and a limiting member 9. The four-bar linkage is located on the chord beam, and the limiting member is located on the spanwise beam.

[0045] The number of spanwise beams is 3. The first spanwise beam is the leading edge of the flapping wing, and the third spanwise beam is the trailing edge of the flapping wing.

[0046] The span beams are parallel to each other, and the chord beams are parallel to each other.

[0047] The spanwise beam at the leading edge is connected to the chordwise beam via a rigid joint, and the spanwise beam at the trailing edge is also connected to the chordwise beam via a rigid joint. The second spanwise beam is connected to the chordwise beam via a flexible joint.

[0048] The rigid joint is connected by bolts and nuts.

[0049] like Figure 4 The four-bar linkage includes link 10, link 21, link 312, link 413, hinge 14, hinge 215, hinge 316, and hinge 417. Link 1 and link 2 are connected by hinge 1, link 2 and link 3 are connected by hinge 2, link 3 and link 4 are connected by hinge 3, and link 4 and link 1 are connected by hinge 4.

[0050] The four-bar linkage is fixed to the chordal beam via hinge one and hinge four, and link one is rotatably connected to the chordal beam via hinge one and hinge four.

[0051] The position of the four-bar linkage at the flexible joint is as follows: Figure 5 Link 2 is parallel to the limiting member and located above link 1, completely restricting the rotation of the chordal beam to the upper side of the spanwise beam. This allows the chordal and spanwise beams of the flexible flapping wing to have a unidirectional rotatable effect at the connection point, and the rotation amplitude is adjustable.

[0052] Example 3

[0053] like Figure 2 A slender flexible flapping wing, wherein one end of the flexible flapping wing is a fixed end 1 and the other end is a free end. The fixed end is connected to the aircraft, and the connection point is located at any position between the leading edge of the flapping wing and the midpoint of the flapping wing in the chord direction. The flapping wing includes a spanwise beam 2, a chord beam 3, and a skin 4. The spanwise beam and the chord beam are connected by a rigid joint 6 and a flexible joint 5 to form a skeleton. The skin surrounds the skeleton and is fixed to the skeleton with adhesive. The flexible joint is connected by a hinge 8. The flexible joint also includes a four-bar linkage 7 and a limiting member 9. The four-bar linkage is located on the chord beam, and the limiting member is located on the spanwise beam.

[0054] The number of spanwise beams is 5. The first spanwise beam is the leading edge of the flapping wing, and the fifth spanwise beam is the trailing edge of the flapping wing.

[0055] The span beams are parallel to each other, and the chord beams are parallel to each other.

[0056] The spanwise beam at the leading edge is connected to the chordwise beam via a rigid joint, and the spanwise beam at the trailing edge is also connected to the chordwise beam via a rigid joint. The second spanwise beam is connected to the chordwise beam via a flexible joint.

[0057] The rigid joint is connected by rivets.

[0058] like Figure 4 The four-bar linkage includes link 10, link 21, link 312, link 413, hinge 14, hinge 215, hinge 316, and hinge 417. Link 1 and link 2 are connected by hinge 1, link 2 and link 3 are connected by hinge 2, link 3 and link 4 are connected by hinge 3, and link 4 and link 1 are connected by hinge 4.

[0059] The four-bar linkage is fixed to the chordal beam via hinge one and hinge four, and link one is rotatably connected to the chordal beam via hinge one and hinge four.

[0060] The position of the four-bar linkage at the flexible joint is as follows: Figure 5Link 2 is parallel to the limiting member and located above link 1, completely restricting the rotation of the chord beam to the upper side of the spanwise beam, so that the chord beam and spanwise beam of the flexible flapping wing have a unidirectional rotatable effect at the connection, and the rotation amplitude can be adjusted.

[0061] Example 4

[0062] like Figure 2 A slender flexible flapping wing, wherein one end of the flexible flapping wing is a fixed end 1 and the other end is a free end. The fixed end is connected to the aircraft, and the connection point is located at any position between the leading edge of the flapping wing and the midpoint of the flapping wing in the chord direction. The flapping wing includes a spanwise beam 2, a chord beam 3, and a skin 4. The spanwise beam and the chord beam are connected by a rigid joint 6 and a flexible joint 5 to form a skeleton. The skin surrounds the skeleton and is fixed to the skeleton with rivets. The flexible joint is connected by a hinge 8. The flexible joint also includes a four-bar linkage 7 and a limiting member 9. The four-bar linkage is located on the chord beam, and the limiting member is located on the spanwise beam.

[0063] The number of spanwise beams is 5. The first spanwise beam is the leading edge of the flapping wing, and the fifth spanwise beam is the trailing edge of the flapping wing.

[0064] The span beams are parallel to each other, and the chord beams are parallel to each other.

[0065] The spanwise beam at the leading edge is connected to the chordwise beam via a rigid joint, and the spanwise beam at the trailing edge is also connected to the chordwise beam via a rigid joint. The second spanwise beam is connected to the chordwise beam via a flexible joint.

[0066] The rigid joint is connected by rivets.

[0067] like Figure 4 The four-bar linkage includes link 10, link 21, link 312, link 413, hinge 14, hinge 215, hinge 316, and hinge 417. Link 1 and link 2 are connected by hinge 1, link 2 and link 3 are connected by hinge 2, link 3 and link 4 are connected by hinge 3, and link 4 and link 1 are connected by hinge 4.

[0068] The four-bar linkage is fixed to the chordal beam via hinge one and hinge four, and link one is rotatably connected to the chordal beam via hinge one and hinge four.

[0069] The position of the four-bar linkage at the flexible joint is as follows: Figure 6 Link 2 is parallel to the limiting member and located on one side of the link, completely restricting the rotation of the chord beam to the upper side of the spanwise beam, so that the chord beam and spanwise beam of the flexible flapping wing have a unidirectional rotatable effect at the connection, and the rotation amplitude can be adjusted.

Claims

1. An elongate flexible flapping wing, characterized by, The flexible flapping wing has a fixed end and a free end, the fixed end is connected with the aircraft, the connection position is between the leading edge of the flapping wing and the chord midpoint of the flapping wing, the flapping wing comprises a spanwise beam, a chordwise beam and a skin, the spanwise beam and the chordwise beam are connected through rigid joints and flexible joints to form a framework, the skin is wrapped outside the framework and is fixed on the framework by an adhesive, the flexible joint is a hinge connection, the flexible joint further comprises a four-bar mechanism and a limiting rod, the limiting rod is located on the spanwise beam, the four-bar mechanism is located on the chordwise beam, the aspect ratio of the slender airfoil is greater than or equal to 3, the number of the spanwise beams is 3, the first spanwise beam is the leading edge of the flapping wing, the third spanwise beam is the trailing edge of the flapping wing, the spanwise beams are parallel to each other, the chordwise beams are parallel to each other, the spanwise beam located at the leading edge is connected with the chordwise beam through a rigid joint, the spanwise beam located at the trailing edge is connected with the chordwise beam through a rigid joint, the second spanwise beam is connected with the chordwise beam through a flexible joint, the connection mode of the rigid joint is bolt and nut connection, the four-bar mechanism comprises a link one, a link two, a link three, a link four, a hinge one, a hinge two, a hinge three and a hinge four, the link one and the link two are connected through the hinge one, the link two and the link three are connected through the hinge two, the link three and the link four are connected through the hinge three, the link four and the link one are connected through the hinge four, the four-bar mechanism is fixed on the chordwise beam through the hinge one and the hinge four, the link one is rotationally connected to the chordwise beam through the hinge one and the hinge four, the link two and the link four are located on the two sides of the link one respectively, the limiting rod limits the rotation amplitude of the chordwise beam to the two sides of the spanwise beam, so that the chordwise beam and the spanwise beam of the flexible flapping wing have a bidirectional rotation effect at the connection position, and the rotation amplitude is adjustable.

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