Underwater flapping wing structure and biomimetic flapping wing underwater robot

Abstract

The application discloses an underwater flapping wing structure and a bionic flapping wing underwater robot, and relates to the technical fields of underwater vehicles and bionic robots. The underwater flapping wing structure comprises a connecting member and a first skin, and the first skin is arranged on the connecting member. The connecting member is used for stretching and contracting in the span direction when deformed by water pressure. The first skin can stretch and contract with the deformation of the connecting member, and the chord width size of the first skin remains unchanged. The bionic flapping wing underwater robot comprises a base, a driving mechanism, a tail fin oscillation mechanism and the underwater flapping wing structure. The tail fin oscillation mechanism and the driving mechanism are arranged on the base, and the output end of the driving mechanism is connected with the connecting member. The first skin can realize adaptive stretching and contraction in the span direction, and the chord width size of the first skin remains unchanged, so that the robot can always maintain the most efficient standard hydrodynamic wing profile boundary in the process of stretching in the span direction and greatly changing the water sweeping area of the wing surface, the flexible variable wing span with low resistance flow is realized, and the propulsion efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of underwater vehicles and biomimetic robots, and in particular to an underwater flapping wing structure and a biomimetic flapping wing underwater robot. Background Technology

[0002] With the deepening of marine exploration, underwater resource development, and deep-sea scientific research, autonomous underwater vehicles (AUVs) and underwater robots are playing an increasingly important role in numerous military, scientific research, and industrial fields. While traditional propeller-driven underwater vehicles are technologically mature, they face performance bottlenecks in areas such as low-speed maneuverability, high-efficiency cruising, and low-noise stealth. As a new and important development direction for underwater vehicle technology, biomimetic flapping-wing underwater robots, by mimicking the swimming postures of marine organisms, have demonstrated significant advantages in improving propulsion efficiency and enhancing maneuverability in complex waters. Aquatic animals in nature, through long-term evolution, have developed the ability to actively change the span and area of ​​their fins or wings according to different swimming speeds and maneuvering needs, thereby achieving optimal hydrodynamic performance during cruising and acceleration. However, most common underwater flapping-wing structures currently employ rigid frames to fix the wingspan or simple flexible skins. When traditional flexible elastic skins stretch or contract in the spanwise direction, due to the physical limitations of the material's Poisson effect, their chordwise direction (i.e., the width direction of the wing surface) will inevitably deform or contract. This chordal contraction caused by spanwise deformation severely disrupts the standard hydrodynamic airfoil of the flapping wing surface, leading to a sharp decrease in propulsion efficiency and an increase in fluid drag. Summary of the Invention

[0003] The purpose of this invention is to provide an underwater flapping wing structure and a biomimetic flapping wing underwater robot to solve the problems existing in the prior art, protect the dynamic airfoil of the flapping wing surface, improve propulsion efficiency and reduce fluid resistance.

[0004] To achieve the above objectives, the present invention provides the following solution: The present invention provides an underwater flapping wing structure, comprising: a connecting member and a first skin, the first skin being disposed on the connecting member; the connecting member being used to deform under water pressure and undergo spanwise expansion and contraction; the first skin being able to expand and contract in the spanwise direction with the deformation of the connecting member, while its chordal width dimension remains unchanged.

[0005] In one embodiment, the connecting member includes two first connecting beams arranged in parallel and spaced apart, the first connecting beams extending longitudinally, the first connecting beams having bends to allow for longitudinal expansion and contraction when deformed by water pressure, and the first skin disposed on the two first connecting beams.

[0006] In one embodiment, the first skin includes a zero Poisson's ratio support structure and a skin body. The zero Poisson's ratio support structure is disposed on the connecting member and can expand and contract synchronously with the connecting member in the spanwise direction while its chord width dimension remains unchanged. The skin body covers the zero Poisson's ratio support structure and can expand and contract synchronously with the Poisson's ratio support structure in the spanwise direction while its chord width dimension remains unchanged.

[0007] In one embodiment, the zero Poisson's ratio support structure includes a matrix that is elastic. A geometric structure on the matrix alters the equivalent macroscopic deformation effect of the matrix. The lateral compensation effect generated by the geometric structure counteracts the chordal contraction of the matrix, enabling the zero Poisson's ratio support structure to stretch and contract with the deformation of the connecting member while maintaining a constant chordal width dimension.

[0008] In one embodiment, the geometric structure is a cross-shaped cutout, which is composed of two intersecting slits, and the angle between each slit and the longitudinal direction is an acute angle. In another embodiment, the connecting member is made of carbon fiber.

[0009] In one embodiment, the system further includes a second skin and a second connecting beam, the second connecting beam being disposed on the rear side of the connecting member; the second connecting beam extends in a direction away from the first connecting beam, and the second connecting beam is covered with the second skin.

[0010] The present invention also provides a biomimetic flapping-wing underwater robot, including a base, a drive mechanism, a tail fin swing mechanism and the above-mentioned underwater flapping-wing structure. The tail fin swing mechanism and the drive mechanism are both disposed on the base, and the output end of the drive mechanism is connected to the connecting member.

[0011] In one embodiment, the tail fin swinging mechanism includes a first power member and a tail fin. The first power member is disposed on the base and the output end of the first power member is connected to the tail fin for driving the tail fin to swing.

[0012] In one embodiment, the driving mechanism further includes a second power component and a transmission assembly, both of which are disposed on the base. The output end of the second power component is drively connected to the transmission assembly, and the transmission assembly is hinged to the first connecting beam.

[0013] The present invention achieves the following technical effects compared to the prior art: This invention discloses an underwater flapping wing structure and a biomimetic flapping wing underwater robot. The first skin can adaptively extend and retract in the spanwise direction while its chord width remains constant. This ensures that the robot can maintain the most efficient standard hydrodynamic airfoil boundary during spanwise stretching and significant changes in the wing surface sweeping water area, achieving flexible variable wing span with low flow resistance and thus improving propulsion efficiency. The connecting components are both rigid and flexible, meeting the requirements of deformation motion while possessing reliable support strength. They fully retain the standard hydrodynamic airfoil shape, reducing fluid resistance and significantly improving the underwater flapping wing's propulsion performance and structural stability. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the structure of the biomimetic flapping-wing underwater robot in Example 2; Figure 2 This is a schematic diagram of the first skin of the underwater flapping wing structure in Embodiment 1; In the diagram: 1. Tail fin; 2. Second skin; 3. Second connecting beam; 4. Second power component; 5. First connecting beam; 6. First skin; 7. Gear; 8. Support frame; 9. Transmission gear shaft; 10. First power component; 11. Base; 12. Connecting component. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] The purpose of this invention is to provide an underwater flapping wing structure and a biomimetic flapping wing underwater robot to solve the problems existing in the prior art, protect the dynamic airfoil of the flapping wing surface, improve propulsion efficiency and reduce fluid resistance.

[0018] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] Example 1 like Figures 1-2As shown, this embodiment provides an underwater flapping wing structure, including: a connecting member 12 and a first skin 6, the first skin 6 being disposed on the connecting member 12; the connecting member 12 is used to undergo spanwise expansion and contraction when deformed by water pressure; the first skin 6 can achieve spanwise expansion and contraction with the deformation of the connecting member 12, while its chordal width dimension remains unchanged.

[0020] The first skin 6 can achieve adaptive expansion and contraction in the spanwise direction, while its chord width dimension remains constant. This ensures that the robot can maintain the most efficient standard hydrodynamic airfoil boundary during the process of spanwise stretching and significant changes in the wing surface sweeping water area, achieving flexible variable wing span with low flow resistance and thus improving propulsion efficiency. The connecting component 12 is both rigid and flexible, meeting the requirements of deformation motion while having reliable support strength. It fully retains the standard hydrodynamic airfoil shape, reduces fluid resistance, and significantly improves the underwater flapping wing propulsion performance and structural stability.

[0021] In one embodiment, the connecting member 12 includes two first connecting beams 5, which are arranged in parallel and spaced apart. The first connecting beams 5 extend along the spanwise direction and have bends to allow spanwise expansion and contraction when deformed by water pressure. A first skin 6 is disposed on the two first connecting beams 5.

[0022] Two parallel connecting beams 5 are arranged at intervals to form a regular load-bearing frame, providing stable installation support for the first skin 6. The overall structure is symmetrical and regular. The first connecting beams 5 have a bent structure, which can achieve spanwise expansion and contraction when deformed by the force of pressurized water, effectively releasing deformation stress and avoiding the problem of stress concentration in the structure. The spanwise extended beam structure can evenly distribute the external water pressure load, enhancing the overall pressure-bearing stability and structural service life. The first connecting beams 5 at the front are relatively robust, bearing the main water resistance and responsible for cutting the water flow, generating dynamic lift to maintain the depth of the biomimetic underwater robot.

[0023] like Figure 1 As shown, in one embodiment, the first skin 6 includes a zero Poisson's ratio support structure and a skin body. The zero Poisson's ratio support structure is disposed on the connecting member 12. The zero Poisson's ratio support structure can expand and contract synchronously with the connecting member 12 in the longitudinal direction, while its chordal width dimension remains unchanged. The skin body covers the zero Poisson's ratio support structure. The skin body can expand and contract synchronously with the Poisson's ratio support structure in the longitudinal direction, while its chordal width dimension remains unchanged.

[0024] The zero Poisson's ratio support structure can maintain motion coordination with the connecting member 12, achieving synchronous expansion and contraction along the spanwise direction, while its dimensions remain constant in the chordwise direction, thus exhibiting excellent deformation coordination performance. This zero Poisson's ratio support structure can provide stable and effective support for the skin body and drive the skin body to deform synchronously, thereby effectively avoiding failure problems such as tension, wrinkling, and cracking caused by uneven local stress or mismatched deformation.

[0025] In one embodiment, the zero Poisson's ratio support structure includes a matrix that is elastic. A geometric structure on the matrix alters the equivalent macroscopic deformation effect of the matrix. The lateral compensation effect generated by the geometric structure counteracts the chordal contraction of the matrix, enabling the zero Poisson's ratio support structure to achieve spanwise expansion and contraction with the deformation of the connecting member 12, while maintaining a constant chordal width. The elastic matrix, combined with the geometric structure, can adapt to the deformation of the connecting member 12 to complete the spanwise expansion and contraction. The chordal dimension remains constant during deformation, effectively maintaining the stability of the structural outline. The elastic material possesses deformation buffering capabilities, which can dissipate deformation stress and prevent structural damage. Relying on the special structural deformation characteristics, the expansion and contraction actions are ensured to be smooth and synchronous, adapting to the deformation requirements of hydraulic conditions.

[0026] In one embodiment, the geometric structure is a cross-shaped perforation, which is composed of two intersecting slits, with each slit forming an acute angle with the spanwise direction. The cross-shaped perforation slits are arranged at acute angles with the spanwise direction, optimizing the structural stress distribution and alleviating stress concentration at corners during deformation; it also improves the flexibility of the zero Poisson's ratio structure in terms of expansion and contraction, ensuring smooth expansion and contraction in the spanwise direction, while suppressing chordal dimensional anomalies and enhancing the structure's resistance to water pressure fatigue deformation.

[0027] In one embodiment, the connecting member 12 is made of carbon fiber.

[0028] The connecting component 12 is made of carbon fiber, which has the characteristics of being lightweight, high-strength, and highly elastic; it effectively reduces the overall weight of the flapping wing, reduces drive energy consumption, and at the same time withstands underwater water pressure impact and repeated bending deformation, thus extending the service life of the structure.

[0029] In one embodiment, it further includes a second skin 2 and a second connecting beam 3, the second connecting beam 3 being disposed on the rear side of the connecting member 12; the second connecting beam 3 extends in a direction away from the first connecting beam 5, and the second connecting beam 3 is covered with the second skin 2.

[0030] The addition of a second connecting beam 3 and a second skin 2 on the rear side extends the flapping wing's aspect ratio coverage; expands the force-bearing area of ​​the wing surface, enhancing underwater propulsion power; the segmented skin structure at the front and rear is clearly layered, further optimizing the conformity to the water flow and improving swimming flexibility; the second connecting beam 3 has a certain degree of flexible adaptability, guiding the trailing edge to displace water backward under the action of flapping phase difference, thereby generating a stable and continuous forward thrust. The second skin 2 undergoes passive flexible deformation in response to the water flow, working together with the first skin to complete a closed hydrodynamic cycle.

[0031] Example 2 like Figure 2 As shown, this embodiment provides a biomimetic flapping-wing underwater robot, including a base 11, a drive mechanism, a tail fin swing mechanism, and an underwater flapping-wing structure as described in Embodiment 1. The tail fin swing mechanism and the drive mechanism are both mounted on the base 11, and the output end of the drive mechanism is connected to the connecting member 12.

[0032] After the drive mechanism is activated, it drives the connecting member 12 to move, causing the underwater flapping fin structure to flap up and down or swing. Because the flapping fin uses a zero Poisson's ratio support structure, its spanwise dimension can expand and contract synchronously with the connecting member 12 while its chordal dimension remains constant. Therefore, the flapping fin is stable in shape during flapping and will not experience localized stretching or wrinkling. Simultaneously, the tail fin swinging mechanism on the base 11 independently controls the left and right swinging of the tail fin, playing a role in balance and auxiliary steering. The drive mechanism and the tail fin swinging mechanism work together to give the robot thrust similar to that of a biological fish, thereby achieving flexible and controllable underwater movement such as forward movement, turning, surfacing, and diving. The overall structure is compact and reliable, with good flapping fin deformation coordination, effectively avoiding the problem of skin cracking and failure due to uneven stress. It provides smooth and efficient swimming, is easy to control, and can adapt to various underwater operation requirements. In one embodiment, a control mechanism is also included. The control mechanism is signal-connected to the drive mechanism and the tail fin swinging mechanism to control their movement. This control mechanism is signal-connected to the drive mechanism and the tail fin swinging mechanism to coordinate the control of their movement. During operation, the control mechanism sends action signals to the drive mechanism according to the preset program or external instructions. The drive mechanism drives the connecting components to move, causing the underwater flapping fin structure to flap up and down or swing in a regular manner. At the same time, the control mechanism also sends instructions to the tail fin swinging mechanism, so that the tail fin swings left and right as needed.

[0033] In one embodiment, the tail fin swinging mechanism includes a first power member 10 and a tail fin 1. The first power member 10 is disposed on the base 11 and the output end of the first power member 10 is connected to the tail fin 1 for driving the tail fin 1 to swing.

[0034] The tail fin oscillation mechanism enhances the flexibility of the biomimetic flapping-wing underwater robot. In actual swimming conditions, when the robot needs to avoid obstacles or change course, the control mechanism sends a PWM pulse signal to the first power unit 10. The first power unit 10 precisely controls the tail fin 1 to oscillate left or right to a preset angle based on the signal. The tail fin 1 disrupts the original wake balance in the flow field, generating a powerful lateral hydrodynamic yaw moment. By superimposing the lateral oscillation steering of the tail with the continuous forward thrust of the underwater flapping wing structure, the entire flapping-wing underwater robot can complete smooth, rapid, and highly maneuverable three-dimensional spatial yaw and turning maneuvers within a very small turning radius.

[0035] In one embodiment, the drive mechanism further includes a second power component 4 and a transmission assembly. Both the second power component 4 and the transmission assembly are disposed on the base 11. The output end of the second power component 4 is connected to the transmission assembly, and the transmission assembly is hinged to a first connecting beam 5.

[0036] The base 11 is provided with a second power component 4 and a support frame 8. The second power component 4 is connected to a gear 7. The gear 7 is connected to other gears 7 through a transmission gear shaft 9. The gear 7 meshes with a set of symmetrically arranged gears and is rotatably connected to the support frame 8. The gear 7 is hinged to a first connecting beam 5.

[0037] After the second power unit 4 is activated, it drives the gear 7 on its output end to rotate. The gear 7 transmits power to other gears 7 connected to it through the transmission gear shaft 9, thereby driving a set of symmetrically arranged gears to rotate synchronously. These gears are all rotatably connected to the support frame 8 to ensure smooth movement. Since the first connecting beam 5 is hinged to the gear 7, when the gear 7 rotates, the hinge point will drive the first connecting beam 5 to produce reciprocating oscillation or push-pull action with the circumferential motion of the gear. Through the symmetrically arranged gear set, the first connecting beams 5 on both sides can achieve synchronous and symmetrical movement, thereby converting the continuous rotational motion of the second power unit 4 into the required periodic oscillation or linear reciprocating motion, providing driving force for the subsequently connected underwater flapping wing or other actuators. This structure has reliable transmission and good motion symmetry, which is beneficial to improving the motion coordination and stability of the biomimetic flapping wing robot.

[0038] The second power component 4 serves as the power source, outputting rotational power to directly drive gear 7, which transmits the power to gears 7 on both sides. The gears 7 on both sides mesh precisely with each other through standard involute tooth profiles. This purely mechanical gear meshing transmission method not only withstands complex underwater variable load impacts but also ensures that the flapping phases of the left and right flapping wing structures remain strictly synchronized at any frequency, ensuring that the robot does not experience unexpected roll or yaw instability during straight-line cruising. The continuous rotational motion of gear 7 is smoothly converted into a large-stroke, high-frequency reciprocating oscillation of the connecting component 12 in the vertical direction through the eccentric structure or linkage mechanism on its end face.

[0039] Work process: In actual swimming operations, when the robot needs to avoid obstacles or change course, the control mechanism sends a PWM pulse signal to the first power unit 10. The first power unit 10 precisely controls the tail fin 1 to swing left or right to a preset angle according to the signal. After the second power unit 4 is started, it drives the gear 7 on its output end to rotate. The gear 7 transmits power to other gears 7 connected to it through the transmission gear shaft 9, thereby driving a set of symmetrically arranged gears to rotate synchronously. When the gear 7 rotates, the hinge point will drive the first connecting beam 5 to produce a reciprocating swing or push-pull action with the circular motion of the gear.

[0040] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. An underwater flapping wing structure, comprising: A connecting member and a first skin, wherein the first skin is disposed on the connecting member; The connecting member is used to undergo spanwise expansion and contraction when deformed by water pressure; characterized in that: the first skin can achieve spanwise expansion and contraction with the deformation of the connecting member, while its chordal width dimension remains unchanged.

2. The underwater flapping wing structure according to claim 1, characterized in that: The connecting member includes two first connecting beams, which are arranged in parallel and spaced apart. The first connecting beams extend longitudinally and are bent to allow for longitudinal expansion and contraction when deformed by water pressure. The first skin is disposed on the two first connecting beams.

3. The underwater flapping wing structure according to claim 2, characterized in that: The first skin includes a zero Poisson's ratio support structure and a skin body. The zero Poisson's ratio support structure is disposed on the connecting member. The zero Poisson's ratio support structure can expand and contract synchronously with the connecting member in the longitudinal direction, while its chordal width dimension remains unchanged. The skin body covers the zero Poisson's ratio support structure, and the skin body can expand and contract synchronously with the Poisson's ratio support structure in the longitudinal direction, while its chordal width dimension remains unchanged.

4. The underwater flapping wing structure according to claim 3, characterized in that: The zero Poisson's ratio support structure includes a matrix that is elastic. The geometric structure on the matrix alters the equivalent macroscopic deformation effect of the matrix. The lateral compensation effect generated by the geometric structure counteracts the chordal contraction of the matrix, enabling the zero Poisson's ratio support structure to achieve spanwise expansion and contraction with the deformation of the connecting member, while keeping the chordal width dimension unchanged.

5. The underwater flapping wing structure according to claim 4, characterized in that: The geometric structure is a cross-shaped cutout, which is composed of two intersecting slits, and the angle between each slit and the longitudinal direction is an acute angle.

6. The underwater flapping wing structure according to claim 1, characterized in that: The connecting component is made of carbon fiber.

7. The underwater flapping wing structure according to claim 1, characterized in that: It also includes a second skin and a second connecting beam, the second connecting beam being disposed on the rear side of the connecting member; the second connecting beam extends in a direction away from the first connecting beam, and the second connecting beam is covered with the second skin.

8. A biomimetic flapping-wing underwater robot, characterized in that: The device includes a base, a drive mechanism, a tail fin swing mechanism, and an underwater flapping fin structure as described in any one of claims 1-7. The tail fin swing mechanism and the drive mechanism are both disposed on the base, and the output end of the drive mechanism is connected to the connecting member.

9. The biomimetic flapping-wing underwater robot according to claim 8, characterized in that: The tail fin swinging mechanism includes a first power component and a tail fin. The first power component is disposed on the base and the output end of the first power component is connected to the tail fin to drive the tail fin to swing.

10. The biomimetic flapping-wing underwater robot according to claim 9, characterized in that: The driving mechanism further includes a second power component and a transmission assembly. Both the second power component and the transmission assembly are mounted on the base. The output end of the second power component is connected to the transmission assembly, and the transmission assembly is hinged to the first connecting beam.

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