Bionic flexible foldable flapping-wing micro-robot

Abstract

The invention relates to the technical field of micro bionic flapping wing flying robots, in particular to a bionic flexible foldable flapping wing micro robot. Comprising a robot body and two flexible wings arranged on the left side and the right side of the robot body. The flexible wing comprises a wing root rotating shaft, a flexible wing membrane, an asymmetric micro joint, a wing leading edge and wing veins, the wing root rotating shaft is fixedly connected with one end of the wing leading edge, and one or more wing veins are arranged below the wing leading edge to jointly form a framework; the flexible wing membrane covers the framework and is connected with the framework; the asymmetric micro-joints are arranged at the joints of the front edges of the wings and veins, and the asymmetric micro-joints are of asymmetric structures, so that the flexible wings present different flexible responses in the up-down flapping movement directions. The asymmetric deformation in the upward and downward flapping directions is realized, so that the aerodynamic efficiency of the flapping wing flight is obviously improved, and the bionic flight effect of increasing the lift force and reducing the resistance can be realized without adding an additional mechanical structure.

Description

Technical Field

[0001] This invention relates to the field of micro bionic flapping-wing flying robot technology, and in particular to a bionic flexible flapping-wing micro robot. Background Technology

[0002] As a rapidly developing biomimetic aircraft in recent years, micro flapping-wing robots, inspired by insect flight mechanisms, have demonstrated unique advantages in scenarios such as small-scale flight, inspection of complex environments, and confined space missions. Existing micro flapping-wing robots primarily rely on the periodic flapping of their wings to generate lift and thrust. Their flapping motion typically employs a symmetrical flapping pattern, meaning that within a flapping cycle, the upward and downward flapping angles and deformation amplitudes of the wings are essentially the same. While symmetrical flapping-wing structures are simple to design and easy to control, they also introduce two typical limitations: first, during the return upward flapping phase, the wings need to overcome significant air resistance, leading to increased energy consumption; second, symmetrical deformation cannot fully utilize the "asymmetric deformation – efficient lift" mechanism present in nature, thus limiting the flight efficiency of microrobots.

[0003] Most currently widely used micro flapping-wing robots employ rigid or semi-rigid wing structures, resulting in fixed wing shapes and a lack of active or passive deformability. While rigid wings can maintain a stable aerodynamic profile during flight, they cannot flexibly adjust to different flight conditions, such as increasing rigidity and lift during a downward flap or reducing air resistance during an upward flap. Furthermore, rigid wings are easily damaged when encountering confined spaces, obstacles, or collisions, and their inability to fold automatically leads to a larger overall size and insufficient environmental adaptability, limiting the application of micro flapping-wing robots in confined spaces, such as inside pipes, equipment gaps, and structural cavities.

[0004] Traditional airfoil structures often employ high-rigidity materials such as carbon fiber struts and plastic frames to ensure the strength and deformation stability of flapping wings. These structures cannot bend at large angles in directions other than flapping, making them susceptible to damage or flight instability when encountering obstacles. Even though some research has attempted folding structures or deformable wing designs, these solutions typically rely on additional mechanical joints, hinges, or independent servos to achieve folding functionality. This not only complicates the structure but also increases weight, impacting the lightweight and reliability requirements of micro flapping-wing robots.

[0005] The structural characteristics of insect wings, which have evolved over a long period of time, have significant advantages. High-speed flying insects, such as dragonflies, employ a typical rigid-flexible coupling structure in their wings, especially the micro-joints system distributed at the intersection of longitudinal and transverse veins.

[0006] While existing micro flapping-wing robots are inspired by insect wings, most only mimic the flapping shape without deeply simulating the asymmetric flexible structural characteristics of insect wings. Therefore, how to introduce asymmetric flexible mechanisms similar to those of dragonflies into engineering implementation, so as to enhance lift when flapping downwards and significantly reduce drag when flapping upwards, has become an urgent technical challenge. Summary of the Invention

[0007] To address the aforementioned problems, the present invention aims to provide a biomimetic flexible flapping-wing microrobot, which solves the common problems of existing micro flapping-wing robots, such as low lift utilization efficiency due to up-and-down flapping symmetry, high drag during the return phase, and rigid wings lacking folding ability and difficulty adapting to narrow spaces.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] This invention provides a biomimetic flexible flapping-wing microrobot, comprising a robot body and two flexible wings disposed on the left and right sides of the robot body;

[0010] The flexible wing includes a wing root rotation axis, a flexible wing membrane, asymmetric microjoints, a wing leading edge, and wing veins. The wing root rotation axis is fixedly connected to one end of the wing leading edge. One or more wing veins are arranged below the wing leading edge to form a skeleton. The flexible wing membrane covers the skeleton and is connected to it. The asymmetric microjoints are located at the connection between the wing leading edge and the wing veins. The asymmetric microjoints are asymmetric structures, which make the flexible wing exhibit different flexible responses in the directions of flapping up and down.

[0011] The asymmetric microjoint includes a connecting part and a limiting part disposed on one side of the connecting part. The connecting part is fixedly connected to the leading edge of the wing, and the limiting part is located on the outside of the flexible wing membrane, so that the flexible wing maintains high rigidity when it flaps down and can fold or bend when it flaps up.

[0012] The leading edge of the wing has a rectangular cross-section, and the width of the rectangular cross-section in the flapping direction is greater than the thickness in the non-flapping direction, which makes the bending stiffness of the leading edge of the wing large in the flapping direction and small in the non-flapping direction.

[0013] The leading edge of the wing is made of nickel-titanium alloy.

[0014] The wing root rotation shaft is fixedly connected to the leading edge of the wing by means of a plug-in adhesive connection.

[0015] The flexible wing membrane is connected to the leading edge of the wing and the wing veins by adhesive bonding, and the flexible wing membrane serves as the main aerodynamic surface.

[0016] The flexible wing membrane is provided with a wing root sleeve at its root, which is used for rotatable connection with the robot body.

[0017] The robot body includes a frame and a flapping mechanism and an attitude control mechanism mounted on the frame. The flapping mechanism is connected to the wing root rotation axis of the flexible wings on both sides, and the flapping mechanism drives the flexible wings on both sides to flap up and down. The attitude control mechanism is used to adjust the robot's flight attitude during flight.

[0018] The robot body also includes a flight control board and a battery respectively located at the top and bottom of the frame.

[0019] The advantages and beneficial effects of this invention are:

[0020] This invention significantly improves the wing's aerodynamic performance, structural adaptability, and environmental interaction capabilities by introducing an asymmetric flexible deformation structure and a rectangular cross-section nickel-titanium alloy leading edge into the wing design of a micro flapping-wing robot. The specific beneficial effects are as follows:

[0021] 1. This invention, by arranging asymmetric microjoints with dorsal-ventral differences in the wing structure, enables the wing to maintain high rigidity and fully deploy during the drooping phase, thereby obtaining a larger effective force-bearing area and lift output; during the up-drooping phase, the wing can fold or bend along the direction of greater flexibility, significantly reducing the frontal area and air resistance. This asymmetric deformation in the up-drooping and down-drooping directions, achieved through the material and structural body, significantly improves the aerodynamic efficiency of flapping wing flight, achieving a biomimetic flight effect of "increased lift and reduced drag" without the need for additional mechanical structures.

[0022] 2. The leading edge of the wing is made of a rectangular cross-section nickel-titanium alloy, giving it high bending stiffness in the flapping direction and large-angle elastic folding capability in the non-flapping direction. This "directional stiffness-flexibility distribution" allows the wing to maintain a stable airfoil during normal flight. When the robot traverses narrow spaces, flies close to walls, or collides with other objects, the wing can actively bend and fold along the non-flapping direction, significantly reducing its profile and avoiding structural damage. Utilizing the superelastic properties of the nickel-titanium alloy, the wing can automatically return to its preset unfolded shape after the external force is removed, eliminating the need for additional folding, locking, or recovery mechanisms, resulting in a lightweight and highly reliable overall structure.

[0023] 3. The foldable wing of this invention significantly enhances the robot's adaptability to complex environments. The flexible wing membrane and the nickel-titanium leading edge deform collaboratively under stress, allowing the wing to conform to the shape of the environment by bending locally or folding entirely. This enables the robot to move freely through confined environments such as inside equipment, structural gaps, and pipe corners. In the event of a sudden collision, the wing can flexibly yield, thus avoiding damage to the wing and drive mechanism and improving the system's durability over long-term use.

[0024] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings.

[0025] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0026] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0027] Figure 1 This is a schematic diagram of the structure of a biomimetic flexible foldable flapping-wing microrobot of the present invention;

[0028] Figure 2 This is a schematic diagram of the flexible wing structure in this invention;

[0029] Figure 3 for Figure 2 Enlarged view of a portion of point A in the middle;

[0030] Figure 4 This is a schematic diagram of the connection of the wing leading edge in this invention;

[0031] Figure 5 This is a schematic diagram of the unbent state of the wing leading edge in this invention;

[0032] Figure 6 This is a schematic diagram of the bending state of the leading edge of the wing in this invention.

[0033] Among them: 1. Flight control board; 2. Flexible wing; 3. Yaw servo; 4. Flapping mechanism; 5. Pitch servo; 6. Roll servo; 7. Battery; 2-1. Wing root rotation shaft; 2-2. Flexible wing membrane; 2-3. Wing root sleeve; 2-4. Asymmetric microjoint; 2-5. Wing leading edge; 2-6. Wing vein. Detailed Implementation

[0034] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0035] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0036] See Figures 1 to 6 As shown, this invention provides a biomimetic flexible flapping-wing microrobot, comprising a robot body and two flexible wings 3 disposed on the left and right sides of the robot body. The flexible wings 3 include a wing root rotation shaft 2-1, a flexible wing membrane 2-2, an asymmetric microjoint 2-4, a wing leading edge 2-5, and wing veins 2-6. The wing root rotation shaft 2-1 is fixedly connected to one end of the wing leading edge 2-5. The wing leading edge 2-5, as the main load-bearing component of the flexible wing 3, extends through the entire wingspan. One or more wing veins 2-6 are arranged below it to form a skeleton, providing support for wing deformation. The flexible wing membrane 2-2 covers and connects to the skeleton. The asymmetric microjoint 2-4 is disposed at the connection between the wing leading edge 2-5 and the wing veins 2-6. The asymmetric microjoint 2-4 has an asymmetric structure, allowing the flexible wing 3 to exhibit different flexible responses in the flapping directions.

[0037] See Figure 2 and Figure 3 As shown, in an embodiment of the present invention, the asymmetric microjoint 2-4 includes a connecting portion and a limiting portion disposed on one side of the connecting portion. The connecting portion is fixedly connected to the leading edge 2-5 of the wing, and the limiting portion is located outside the flexible wing membrane 2-2 and the wing veins 2-6, so that the flexible wing 3 maintains high stiffness when flapping downwards and can fold or bend when flapping upwards, resulting in different flexible responses of the flexible wing 3 in the flapping and upward movement directions. Specifically, when the flexible wing 3 flaps downwards, the limiting portion of the asymmetric microjoint 2-4 maintains high stiffness of the flexible wing 3, thereby achieving full deployment and enhancing lift; while when flapping upwards, the flexibility in the ventral direction is greater, allowing the flexible wing 3 to fold or bend, reducing the frontal area and significantly reducing air resistance. In other words, the asymmetric microjoint 2-4 enables the flexible wing 3 to produce differentiated deformation in the flapping and upward movement directions. Without relying on additional servos or mechanisms, the flexible wing 3 can automatically achieve a biomimetic motion mode of "increasing lift when flapping downwards and reducing drag when flapping upwards," greatly improving the aerodynamic performance and adaptability of the flapping-wing robot.

[0038] Preferably, the leading edge 2-5 of the wing is made of nickel-titanium alloy material. Nickel-titanium alloy has significant superelasticity and good fatigue performance, and can automatically recover its original shape after large bending deformation.

[0039] Furthermore, the leading edge 2-5 of the wing has a rectangular cross-section, and the width of the rectangular cross-section in the flapping direction is greater than its thickness in the non-flapping direction. This gives the leading edge 2-5 high bending stiffness in the flapping direction, providing sufficient structural support and ensuring that the flexible wing 3 maintains a stable leading edge shape during downward and upward flapping movements, guaranteeing effective lift generation. In the non-flapping direction, the bending stiffness is low. When the flexible wing 3 is subjected to lateral compression, collision, or enters a confined space, the leading edge 2-5 can undergo large-angle elastic bending in that direction, causing the flexible wing 3 to passively fold closer to the fuselage, thereby significantly reducing its overall dimensions. (See [reference]). Figure 5 and Figure 6 As shown, the wing leading edge 2-5 can automatically return to its preset unfolded shape after the external force is removed, without the need for additional folding or unfolding mechanisms. During flight, flapping inertia and aerodynamic forces can assist the wing leading edge 2-5 in naturally unfolding the flexible wing 3, ensuring a good airfoil during the descent phase. During descent, wall-hugging, or gap-crossing conditions, the flexibility of the wing leading edge 2-5 in the ventral direction allows the flexible wing 3 to fold or bend directionally, reducing frontal area and aerodynamic drag. Through the design of the rectangular cross-section nickel-titanium alloy leading edge described above, this invention simultaneously achieves high-rigidity support in the flapping direction and large-deformation flexibility in the non-flapping direction on the same component, and endows the wing with folding and impact resistance under the premise of extremely simplified structure, providing the core material and structural foundation for flexible asymmetric flapping wings.

[0040] Specifically, the wing root rotation shaft 2-1 is fixedly connected to the wing leading edge 2-5 by means of a plug-in adhesive connection, enabling the flexible wing 3 to complete up-and-down flapping motion. The flexible wing membrane 2-2 is connected to the wing leading edge 2-5 and wing vein 2-6 by adhesive connection. As the main aerodynamic surface, the flexible wing membrane 2-2 enables the flexible wing 3 to passively bend according to aerodynamic forces during flapping motion.

[0041] Furthermore, the flexible wing membrane 2-2 is provided with a wing root sleeve 2-3 at its root, which is used for rotatable connection with the robot body.

[0042] In embodiments of the present invention, the robot body includes a frame and a flapping mechanism 4 and an attitude control mechanism mounted on the frame. The flapping mechanism 4 is connected to the wing root rotation shaft 2-1 of the flexible wings 3 on both sides, and the flapping mechanism 4 drives the flexible wings 3 to flap up and down. The flapping mechanism 4 can adopt a combination of crank-slider mechanism and cable transmission to convert linear reciprocating motion into reciprocating rotation of the wing root rotation shaft 2-1, thereby realizing the up and down flapping motion of the flexible wings 3. The attitude control mechanism is used to adjust the robot's flight attitude during flight. Specifically, the attitude control mechanism includes a yaw servo 3, a pitch servo 5, and a roll servo 6, used to adjust the robot's yaw, pitch, and roll attitude during flight.

[0043] Furthermore, the robot body also includes a flight control board 1 and a battery 7, respectively located in the central area at the top and bottom of the frame. The flight control board 1 is used to perform attitude calculation, flapping wing control, and coordinated drive of various servos. The battery 7 provides power to the entire robot and ensures a reasonable center of gravity distribution. The overall structure adopts a lightweight layout, enabling the robot to have stable flapping wing drive and attitude adjustment capabilities, and providing a structural foundation for subsequent asymmetric flexible deformation and foldable wing functions.

[0044] This invention utilizes a rectangular cross-section nickel-titanium alloy material at the leading edge 2-5 of the wing, enabling the flexible wing 3 to achieve high bending stiffness in the flapping direction. This provides stable support for the effective airfoil during the downward phase, thereby maximizing lift generation. Simultaneously, the lateral flexibility of the leading edge 2-5 allows the wing to undergo large-angle elastic deformation in the non-flapping direction during the upward phase or when encountering external obstacles, causing the flexible wing 3 to passively fold to reduce air resistance or decrease volume. The nickel-titanium alloy exhibits significant superelasticity, automatically returning to its original shape after the external force is removed. This eliminates the need for an additional drive mechanism during the folding and unfolding of the flexible wing 3, resulting in a lightweight and highly reliable structure.

[0045] Beyond material innovation, this invention structurally mimics the micro-joint characteristics of a dragonfly's wings. By creating a flexible connection layout with different dorsal and ventral properties at the connection area between the leading edge 2-5 of the wing and the flexible wing membrane 2-2, the deformation of the flexible wing 3 exhibits asymmetry. During the downward flapping phase, the flexibility on the dorsal side is restricted, allowing the flexible wing 3 to maintain high overall stiffness and fully unfold, creating a larger stress-bearing area to enhance lift. Conversely, during the upward flapping phase, due to the greater flexibility on the ventral side, the flexible wing 3 is more prone to folding or localized bending, reducing air resistance and energy loss. This asymmetric structural characteristic of "enhanced downward flapping and unloaded upward flapping" effectively reproduces the natural mechanical mechanism of a dragonfly's wings, enabling the micro flapping-wing robot to significantly improve energy efficiency while ensuring flight stability.

[0046] The flexible, foldable structure of this invention also possesses excellent environmental adaptability. When flying in confined spaces, near walls, or during collisions, the flexible wing 3 can automatically fold along the non-flapping direction, instantly reducing the overall size of the robot and preventing damage or jamming of the flexible wing 3. Utilizing the self-healing properties of the nickel-titanium alloy, the flexible wing 3 can return to its preset airfoil after overcoming obstacles, eliminating the need for a complex mechanical folding system and ensuring lightweight and high reliability of the entire structure. The entire system coordinates flapping and attitude control via a flight control board, enabling the robot to perform tasks such as efficient biomimetic flapping flight, wall-climbing, and narrow-space traversal.

[0047] This invention provides a biomimetic flexible flapping-wing microrobot with a novel flapping wing structure featuring asymmetric flexible joint characteristics and superelastic flapping capability. This flapping wing structure draws inspiration from the biomechanical characteristics of dragonfly wings, achieving asymmetric dorsoventral deformation behavior similar to insect wings through the combination of artificial materials and engineering structures. Furthermore, the use of a rectangular nickel-titanium alloy leading edge provides sufficient stiffness in the flapping direction, while enabling large-angle flexible folding and automatic recovery in the non-flapping direction, thereby improving the microrobot's flight efficiency and environmental adaptability.

[0048] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A biomimetic flexible flapping-wing microrobot, characterized in that, Includes the robot body and two flexible wings (3) located on the left and right sides of the robot body; The flexible wing (3) includes a wing root rotation shaft (2-1), a flexible wing membrane (2-2), an asymmetric microjoint (2-4), a wing leading edge (2-5), and wing veins (2-6). The wing root rotation shaft (2-1) is fixedly connected to one end of the wing leading edge (2-5). One or more wing veins (2-6) are arranged below the wing leading edge (2-5) to form a skeleton. The flexible wing membrane (2-2) covers the skeleton and is connected. The asymmetric microjoint (2-4) is located at the connection between the wing leading edge (2-5) and the wing vein (2-6). The asymmetric microjoint (2-4) is an asymmetric structure, which makes the flexible wing (3) exhibit different flexible responses in the up-and-down flapping directions.

2. The biomimetic flexible foldable flapping-wing microrobot according to claim 1, characterized in that, The asymmetric microjoint (2-4) includes a connecting part and a limiting part disposed on one side of the connecting part. The connecting part is fixedly connected to the leading edge (2-5) of the wing, and the limiting part is located outside the flexible wing membrane (2-2), so that the flexible wing (3) maintains high rigidity when it flaps down and can fold or bend when it flaps up.

3. The biomimetic flexible foldable flapping-wing microrobot according to claim 1, characterized in that, The leading edge (2-5) of the wing has a rectangular cross-section, and the width of the rectangular cross-section in the flapping direction is greater than the thickness in the non-flapping direction, so that the leading edge (2-5) of the wing has a large bending stiffness in the flapping direction and a small bending stiffness in the non-flapping direction.

4. The biomimetic flexible foldable flapping-wing microrobot according to claim 3, characterized in that, The leading edge (2-5) of the wing is made of nickel-titanium alloy.

5. The biomimetic flexible flapping-wing microrobot according to claim 1, characterized in that, The wing root rotation shaft (2-1) is fixedly connected to the wing leading edge (2-5) by means of a plug-in adhesive connection.

6. The biomimetic flexible foldable flapping-wing microrobot according to claim 1, characterized in that, The flexible wing membrane (2-2) is connected to the leading edge of the wing (2-5) and the wing veins (2-6) by adhesive bonding, and the flexible wing membrane (2-2) serves as the main aerodynamic surface.

7. The biomimetic flexible flapping-wing microrobot according to claim 1, characterized in that, The flexible wing membrane (2-2) is provided with a wing root sleeve (2-3) at its root, which is used to rotate and connect with the robot body.

8. The biomimetic flexible foldable flapping-wing microrobot according to claim 1, characterized in that, The robot body includes a frame and a flapping mechanism and an attitude control mechanism mounted on the frame. The flapping mechanism is connected to the wing root rotation shaft (2-1) of the flexible wings (3) on both sides, and the flexible wings (3) on both sides are driven by the flapping mechanism to flap up and down. The attitude control mechanism is used to adjust the robot's flight attitude during flight.

9. The biomimetic flexible foldable flapping-wing microrobot according to claim 8, characterized in that, The robot body also includes a flight control board (1) and a battery (7) respectively located at the top and bottom of the frame.

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