A miniature biomimetic folding flapping wing system and its aircraft

Abstract

This invention discloses a miniature biomimetic folding flapping wing system and its aircraft, belonging to the field of flapping wing aircraft. It includes a flapping wing, comprising wing veins and a wing membrane adhered to the wing veins. The wing veins are arranged radially, with gaps between adjacent veins, forming a flexible hinge with the wing membrane. A horizontal rod is provided on the spandex side of the folding wing to apply torque to the wing veins for unfolding and contraction, and a vertical rod is provided on the chordal side of the folding wing for connection to the fuselage of the flapping wing aircraft. The flexible hinge formed by the wing veins and wing membrane ensures the regular folding of the wing without adding extra mass.

Description

Technical Field

[0001] This disclosure pertains to the field of flapping-wing aircraft, specifically relating to a micro biomimetic folding flapping-wing system and its aircraft. Background Technology

[0002] The concept of micro air vehicles was first proposed by the RAND Corporation in the United States. Micro flapping-wing aircraft have become a research hotspot in the field of micro air vehicles because they can hover under conditions of small size and low Reynolds number, and have advantages such as low aerodynamic noise, high maneuverability, good stealth, high energy efficiency and high safety. They have broad application prospects in both military and civilian fields.

[0003] To further improve the overall performance and reduce the size of micro flapping-wing aircraft, some researchers are looking to solutions from Coleoptera (such as beetles). The wing-folding mechanism of beetles offers a way to reduce the size of aircraft, protecting the structure on the ground and unfolding to provide aerodynamics during flight. However, existing biomimetic foldable wings often fail to meet the requirements of practical flight due to their complex folding process or excessive weight.

[0004] Currently, most micro flapping-wing aircraft lack folding capabilities, are bulky, and inconvenient to carry. Existing biomimetic foldable wings are difficult to apply in actual flight due to their complex design, small folding ratio, or heavy weight. These problems urgently need to be solved in order to develop a biomimetic folding wing system that can reduce the size of the aircraft while possessing excellent flight performance.

[0005] Based on the above problems, a micro-bionic folding flapping wing system and its aircraft are proposed. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the purpose of this disclosure is to provide a micro-bionic folding flapping-wing system and its aircraft, which solves the problem that flapping-wing aircraft in the prior art do not have folding functionality.

[0007] The objective of this disclosure can be achieved through the following technical solutions:

[0008] A miniature biomimetic folding flapping wing system includes flapping wings, the flapping wings including wing veins and wing membranes adhered to the wing veins;

[0009] The wing veins are arranged radially, and there is a gap between two adjacent wing veins, forming a flexible hinge with the wing membrane;

[0010] The folding wing has a horizontal rod on its spandex side that applies torque to the wing veins to expand and contract, and a vertical rod on its chord side for connecting to the fuselage of the flapping wing aircraft.

[0011] In some cases, it can also be achieved in the following way;

[0012] An aircraft comprising a micro-bionic folding flapping wing system;

[0013] Miniature biomimetic folding flapping wing system;

[0014] This includes flapping wings, which consist of wing veins and wing membranes attached to the wing veins;

[0015] The wing veins are arranged radially, and there is a gap between two adjacent wing veins, forming a flexible hinge with the wing membrane;

[0016] The folding wing has a horizontal rod on its spandex side that applies torque to the wing veins to expand and contract, and a vertical rod on its chord side for connecting to the fuselage of the flapping wing aircraft.

[0017] The beneficial effects of this disclosure are:

[0018] 1. The hinge mechanism enhances the stability of the folding wing after it is deployed. The rotation direction of the hinge mechanism is perpendicular to the flapping direction of the wing. The hinge ensures the stiffness in the flapping direction, so that no folding will occur during flapping, ensuring that the wings can generate maximum lift when flapping.

[0019] 2. Ultra-thin carbon fiber plates are used as wing veins and are bonded to the wing membrane by hot pressing, which ensures the strength of the wings while controlling the quality.

[0020] 3. The wing veins and wing membrane form a flexible hinge, which ensures the regular folding of the wings without adding extra mass;

[0021] 4. A temperature-controlled nickel-titanium alloy spring is used to control the folding and unfolding of the wings, making the mechanism lightweight and easy to control.

[0022] 5. The structural components are made of nylon 3D printing, and the carbon fiber rods and carbon fiber plates can be directly cut and manufactured. All other components can be purchased directly. The hinges adopt a nested installation structure, and the wings are formed by hot pressing and bonding. The overall system is lightweight, low in cost, and easy to process and assemble. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a flapping wing assembly diagram of a miniature flapping-wing aircraft according to the present invention;

[0025] Figure 2 This is a schematic diagram of the wire drive of the present invention;

[0026] Figure 3 This is an exploded view of the assembly of the one-way hinge mechanism of the present invention;

[0027] Figure 4 This is an exploded view of the assembly of the biomimetic foldable wings of the present invention;

[0028] Figure 5 This is a schematic diagram of the biomimetic foldable wing of the present invention;

[0029] Figure 6 This is an exploded view of the assembly of the nickel-titanium alloy spring drive mechanism of the present invention;

[0030] Figure 7 This is a schematic diagram of the folding wing folding process of the present invention;

[0031] The components include: 1. Hinge mechanism; 2. Bionic foldable wing; 3. Nickel-titanium alloy spring drive mechanism; 4. Pull wire; 1-1 Hinge outer shell; 1-2 Miniature torsion spring; 1-3 Pin; 1-4 Hinge inner shell; 2-1 Wing membrane; 2-2 First wing vein; 2-3 Second wing vein; 2-4 Third wing vein; 2-5 Fourth wing vein; 2-6 Fifth wing vein; 2-7 Wing vertical rod; 2-8 Wing horizontal rod; 3-1 Drive mechanism frame; 3-2 Spring pressure plate; 3-3 Temperature-controlled nickel-titanium alloy spring; 3-4 Slider; 3-5 Carbon fiber rod. Detailed Implementation

[0032] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0033] like Figures 1-7 As shown, a miniature biomimetic folding flapping wing system includes;

[0034] A foldable flapping wing, comprising wing veins and a wing membrane 2-1 adhered to the wing veins;

[0035] The flapping wing has multiple radially arranged wing veins, and the wing veins and wing membrane 2-1 form a flexible hinge. Thus, when the flapping wing needs to be folded, a torque is applied to the wing veins so that the flapping wing will fold in a regular fan shape from the center point of the radial arrangement of the wing veins.

[0036] The wing veins can be sheet-like, fan-shaped, net-like, etc. In some embodiments, the specific structure of the flapping wing is as follows: Figure 1 , Figure 2 and Figure 4 As shown;

[0037] The biomimetic foldable wing 2 includes a wing membrane 2-1, a first wing vein 2-2, a second wing vein 2-3, a third wing vein 2-4, a fourth wing vein 2-5, and a fifth wing vein 2-6;

[0038] The wing membrane 2-1 is made of 0.05-0.2mm polyimide material, which has good mechanical properties and high heat resistance. It can withstand the aerodynamic force generated by flapping and is suitable for subsequent hot pressing processing. A thickness of 0.1mm is preferred.

[0039] All five wing veins are laser-cut from 0.1mm to 0.3mm carbon fiber plates. Each wing vein includes two vertical rods with a horizontal rod between them. The included angle between the two vertical rods of the first wing vein 2-2, the second wing vein 2-3, the fourth wing vein 2-5, and the fifth wing vein 2-6 is 22.5 degrees, which sums to 90 degrees. The two vertical rods of the third wing vein 2-4 are horizontal to each other. The end side lengths of the first, second, third, and fourth wing veins are similar to those of the third wing vein 2-4, and a thickness of 0.2mm is preferred.

[0040] Five wing veins are alternately bonded to both sides of the wing membrane 2-1 by PET hot adhesive through a 120-degree hot pressing process. A gap of about 0.1 to 0.3 mm is left between each wing vein. The wing veins and the wing membrane 2-1 form a flexible hinge, which allows the wings to fold in a regular fan shape. The recommended gap is 0.2 mm.

[0041] The folding process of the folding wing is as follows Figure 6 As shown, in the folded state, the wing membrane 2-1 overlaps with the third wing vein 2-4 under the influence of the first wing vein 2-2, the second wing vein 2-3, the fourth wing vein 2-5, and the fifth wing vein 2-6. In the folded state, the order of the wing veins from top to bottom is the third wing vein 2-4, the second wing vein 2-3, the fourth wing vein 2-5, the first wing vein 2-2, and the fifth wing vein 2-6.

[0042] In some implementation schemes

[0043] The biomimetic foldable wing 2 has a spread length of 120mm and a chord length of 35mm when unfolded, and a spread length of 27mm when folded.

[0044] The long side of the biomimetic foldable wing 2 is bonded to the horizontal rod of wing 2-8 and connected to the drive device that applies torque to the wing veins of the flapping wing to expand and contract. The recommended diameter is 1mm and the material is carbon fiber. The long side of the chord is bonded to the vertical rod of wing 2-7 and connected to the fuselage of the flapping wing aircraft. The recommended diameter is 0.7mm and the material is carbon fiber. The hinge mechanism 1 is connected to the flapping mechanism of the aircraft to drive the flapping of the wings to generate lift.

[0045] Furthermore, the driving device is connected to a hinge mechanism 1, a micro motor, etc.;

[0046] In some embodiments, the system includes a hinge mechanism 1 for driving the bionic foldable wings 2 to unfold and fold; the fixed hinge housing of the hinge mechanism 1 is fixedly installed on the output end of the flapping mechanism of the flapping wing aircraft, and the hinge mechanism 1 is provided with a movable hinge housing that is interconnected with the 2-8 wing horizontal rods and is rotatable. The attitude of the bionic foldable wings 2 is controlled by the rotation of the movable hinge housing, and the movable hinge housing can be driven by a motor, an electric piston cylinder, or a cable.

[0047] In some embodiments, the hinge mechanism 1 has the following specific structure: Figure 3 As shown, the hinge mechanism 1 includes a hinge outer shell 1-1, a miniature torsion spring 1-2, a pin 1-3, and a hinge inner shell 1-4;

[0048] The hinge outer shell 1-1 and the hinge inner shell 1-4 are fabricated by 3D printing of nylon.

[0049] The inner hinge housing 1-4 is nested in the outer hinge housing 1-1, and the miniature torsion spring 1-2 is nested in the inner hinge housing 1-4. The two ends of the miniature torsion spring 1-2 are fixed to the inner hinge housing 1-4 and the outer hinge housing 1-1 respectively through mounting holes. The pin 1-3 is clearance-fitted with the inner hinge housing 1-4 and interference-fitted with the outer hinge housing 1-1. During installation, the pin 1-3 passes through the two housings and the miniature torsion spring 1-2 to fix them. All three serve as the pivot of the hinge.

[0050] The two housings can rotate relative to each other around the pivot pins 1-3. When in the horizontal position, they cannot continue to rotate in the opposite direction due to the upper limit. The relative rotation angle between the two housings is approximately 90 degrees.

[0051] The initial angle of the miniature torsion springs 1-2 is 180 degrees, which makes the two shells relatively parallel in their original state. When the hinges rotate relative to each other, the two shells always tend to return to being relatively parallel under the action of the torsion springs.

[0052] like Figure 1 As shown, the hinge outer shell 1-1 is connected to the output end of the flapping mechanism of the flapping wing aircraft by an interference fit, and the hinge inner shell 1-4 is connected to the bionic foldable wing 2. The two shells can only rotate relative to each other along the vertical plane and cannot rotate relative to each other along the horizontal plane, which ensures that the output of the flapping mechanism is effectively transmitted to the wings of the aircraft and that the wings do not fold during the flapping process.

[0053] The inner hinge housing 1-4 has a binding ring for connecting to the pull wire 4, and the outer hinge housing 1-1 has a guide hole for the pull wire 4 to guide it, ensuring that the tension of the pull wire 4 is correctly applied to the hinge, causing the hinge to rotate. The path of the pull wire 4 is as follows: Figure 2 As shown.

[0054] In some embodiments, the pull wire 4 is driven by a nickel-titanium alloy spring drive mechanism 3; such as Figure 5As shown, the nickel-titanium alloy spring drive mechanism 3 includes a drive mechanism frame 3-1, two spring pressure plates 3-2, a temperature-controlled nickel-titanium alloy spring 3-3, a slider 3-4, and two carbon fiber rods 3-5.

[0055] The drive mechanism frame 3-1 and slider 3-4 are made of nylon 3D printing, and the spring pressure plate 3-2 is made of 0.2mm 304 stainless steel by laser cutting.

[0056] The drive mechanism frame 3-1 is mounted on the aircraft frame via an interference fit.

[0057] The two ends of the temperature-controlled nickel-titanium alloy spring 3-3 are respectively clamped to the drive mechanism frame 3-1 and the slider 3-4 by spring pressure plates 3-2 through M1 bolts and nuts;

[0058] The carbon fiber rod 3-5 is the guide rod for the movement of the slider 3-4. It is installed on the drive mechanism frame 3-1 with an interference fit, and at the same time, it is clearance-fitted with the slider 3-4. This allows the slider 3-4 to move along the guide rod. If necessary, lubricating oil should be applied to reduce the resistance during movement.

[0059] The spring pressure plate 3-2 presses the nickel-titanium alloy spring against the frame and slider 3-4 while pressing the wire against the nickel-titanium alloy, ensuring a reliable connection between the wire and the spring.

[0060] The temperature-controlled nickel-titanium alloy spring 3-3 has shape memory properties. It will return to its contracted state at high temperatures and has a large elastic modulus. At room temperature, it has a very small elastic modulus and is easily stretched and undergoes plastic deformation.

[0061] The two ends of the spring are connected to the wires. When an electric current is applied, heat is generated by Joule's law. The nickel-titanium alloy spring is heated to a high temperature, and the spring contracts, thereby driving the slider 3-4 to move.

[0062] One end of the pull wire 4 is tied and fixed to the binding ring of the inner housing 1-4 of the hinge, and the other end is tied and fixed to the slider 3-4 after passing through the guide hole of the pull wire 4 in the outer housing 1-1 of the hinge and the guide hole of the pull wire 4 in the drive mechanism frame 3-1, so as to transmit the movement of the nickel-titanium alloy spring. The path of the pull wire 4 is as follows: Figure 2 As shown;

[0063] When the temperature-controlled nickel-titanium alloy spring 3-3 is heated by electricity, the spring contracts and pulls the slider 3-4 to move. The slider 3-4 pulls the hinge mechanism 1 to rotate through the pull wire 4, and the folding wing is folded. At this time, the miniature torsion spring 1-2 of the hinge mechanism 1 is in a torsion state.

[0064] After the temperature-controlled nickel-titanium alloy spring 3-3 stops being heated, the spring returns to room temperature and its elastic modulus decreases. The miniature torsion spring 1-2 of the hinge mechanism 1 will drive the hinge mechanism 1 to rotate, the folding wing will unfold, and at the same time, the slider 3-4 will be pulled to stretch the nickel-titanium alloy spring.

[0065] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0066] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A microbionic folding flapping wing system comprising a flapping wing wing, characterized in that, Flapping wings consist of wing veins and wing membranes that adhere to the wing veins; The wing veins are arranged radially, and there is a gap between two adjacent wing veins, forming a flexible hinge with the wing membrane; The folding wing has a horizontal rod on its spandex side that applies torque to the wing veins to expand and contract, and a vertical rod on its chord side for connecting to the fuselage of the flapping wing aircraft. The flapping wing includes a first wing vein, a second wing vein, a third wing vein, a fourth wing vein, and a fifth wing vein. The angle between the two vertical bars of the first wing vein, the second wing vein, the fourth wing vein, and the fifth wing vein is 22.5 degrees, and the two vertical bars of the third wing vein are horizontal to each other. The flapping wing system includes a hinge mechanism for driving the flapping wing to unfold and fold; the fixed hinge housing of the hinge mechanism is fixedly installed on the output end of the flapping mechanism of the flapping wing aircraft, and the hinge mechanism is provided with a movable hinge housing that is interconnected with the horizontal rod and can rotate. The movable hinge housing of the hinge mechanism is driven by a nickel-titanium alloy spring with active temperature control. The flapping wing system includes a nickel-titanium alloy spring drive mechanism mounted on the aircraft frame; the nickel-titanium alloy spring drive mechanism includes; The slider is movably mounted on the guide rod and connected to the movable hinge housing via a pull line; The temperature-controlled nickel-titanium alloy spring has conductive circuits connected to both ends to drive the slider movement. The two ends are respectively mounted on the drive mechanism frame and the slider.

2. A micro bio-inspired flapping foil system according to claim 1, characterized in that, The wing membrane is made of 0.05-0.2mm polyimide.

3. A micro bio-inspired flapping foil system according to claim 1, wherein, The wing veins include two vertical rods, with a horizontal rod between the two vertical rods.

4. A miniature biomimetic folding flapping wing system according to claim 1, characterized in that, The wing veins are prepared by laser cutting of 0.1mm to 0.3mm carbon fiber plates.

5. A miniature biomimetic folding flapping wing system according to claim 1, characterized in that, The wing veins are alternately bonded to both sides of the wing membrane by PET hot adhesive through a 120-degree hot pressing process, with a gap of 0.1 to 0.3 mm between each wing vein.

6. An aircraft, characterized in that, The aircraft includes a micro-bionic folding flapping wing system as described in any one of claims 1-5.

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