A biomimetic propulsion structure for AUVs
By using a biomimetic AUV propulsion structure designed with biomimicry, and utilizing the swaying motion of the manta ray's pectoral fins, the problem of high noise in traditional propeller propulsion is solved, achieving low-noise, low-drag, and highly efficient underwater propulsion.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- HOHAI UNIV
- Filing Date
- 2025-06-17
- Publication Date
- 2026-06-02
AI Technical Summary
The cavitation phenomenon caused by the propeller propulsion of traditional AUVs generates high noise, which has become a technical bottleneck in fields such as military reconnaissance.
The biomimetic propulsion structure of the AUV is designed using biomimetic principles. It utilizes the swaying motion of the manta ray's pectoral fins and achieves propulsion through the reciprocating swaying of two sets of pectoral fin components, avoiding the high-speed rotation of the propeller. A wing rod is designed to control the wingtip vortex.
It effectively reduces noise, eliminates the conditions for cavitation bubble generation, achieves low-noise propulsion, and improves propulsion efficiency.
Smart Images
Figure CN224311965U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of AUV propulsion structure technology, specifically relating to a biomimetic propulsion structure for AUVs. Background Technology
[0002] As marine exploration activities continue to deepen, autonomous underwater vehicles (AUVs) are becoming increasingly important in fields such as marine engineering, military defense, and ecological environmental protection.
[0003] Traditional AUVs use propellers as their propulsion system. When the propeller rotates, the fluid velocity on the blade surface increases, causing the liquid to vaporize and form cavitation bubbles, thus inducing cavitation. The shock waves generated by the collapse of these cavitation bubbles produce a significant "bursting sound," resulting in high noise levels in the propulsion system. In fields with stringent noise control requirements, such as military reconnaissance, the high noise characteristics of this propulsion method have become a significant technical bottleneck.
[0004] Bionics is a discipline that explores the structure, function, and evolutionary laws of organisms in nature. The manta ray, a typical cartilaginous fish, uses its pectoral fins as its primary propulsion organs, generating thrust and lift through undulating motion to propel its body forward. Its caudal fin possesses flexible undulating capabilities, allowing for precise control of its direction of movement by adjusting undulating parameters. This unique propulsion mechanism fundamentally solves the problem of excessive noise.
[0005] In view of this, this scheme proposes a biomimetic propulsion structure for AUVs based on the analysis of manta ray movement mechanism, aiming to avoid the application of traditional propeller propulsion methods and provide research ideas for solving the problem of underwater propulsion noise of AUVs. Utility Model Content
[0006] To address the problems in the existing technology, this utility model proposes a biomimetic propulsion structure for AUVs.
[0007] To achieve the above objectives, the present invention proposes the following technical solution:
[0008] A biomimetic propulsion structure for an AUV includes a fuselage frame assembly and two sets of pectoral fin assemblies, one large and one small. The pectoral fin assemblies are located at both ends of the fuselage frame assembly, and each set of pectoral fin assemblies contains two single-wing assemblies of the same size. The single-wing assemblies of the same size are symmetrically arranged along a plane P, which is a plane that is parallel to the forward direction X and along the vertical direction.
[0009] The body frame components include:
[0010] The support rod extends along the X direction.
[0011] Two double-wing connecting assemblies are respectively installed at both ends of the support rod; the double-wing connecting assembly includes a mounting base fixedly connected to the support rod, and two inclined brackets fixedly connected to the mounting base; two uprights are fixedly connected to the mounting base, and a gear is rotatably connected to each of the two uprights, and the two gears mesh with each other; the axis of the gears is parallel to the X direction; the gears are driven to rotate by a motor.
[0012] The single-wing assembly includes:
[0013] The pivot is rotatably connected to the inclined support, and the axis of rotation is parallel to the X direction;
[0014] The linkage is rotatably connected to the gear via shaft one. Shaft one is located at a non-center position on the plane of the gear, and the axis of shaft one is parallel to the X direction.
[0015] Both the first hinge shaft and the second hinge shaft are rotatably connected to the linkage rod, and their axes are parallel to the X direction. From the perspective of the length direction of the linkage rod, the distance between the first hinge shaft and the first shaft is set to be closer, and the distance between the second hinge shaft and the first shaft is set to be farther.
[0016] The large wing rod has one end fixedly connected to the second hinge shaft and can rotate relative to the linkage rod through the second hinge shaft; the middle part of the large wing rod passes through the pivot shaft and is fixedly connected to the pivot shaft.
[0017] The small wing rod has one end fixedly connected to the first hinge shaft and can rotate relative to the linkage rod through the first hinge shaft;
[0018] The wing rod is Y-shaped, with one end of its top forked end rotatably connected to the other end of the large wing rod via shaft three, and the other end of the forked end rotatably connected to the other end of the small wing rod via shaft four; the axes of shaft three and shaft four are both parallel to the X direction;
[0019] Several airfoil frames are fixedly connected to the main wing shaft or wing shaft. The suction surface of the airfoil frames faces upward and the pressure surface faces downward. The chord of the airfoil frames makes an angle with the horizontal plane, ensuring that when swinging downward, a forward thrust is generated due to the reaction force of the water.
[0020] This propulsion structure also includes waterproof fabric, which is heat-pressed onto the surface of the airfoil skeleton and can cover the entire airfoil skeleton.
[0021] Furthermore, the mounting base is provided with a mounting position, and the motor is mounted in the mounting position.
[0022] It enables accurate installation of the motor, facilitating precise engagement (meshing) of the gears connected to the motor shaft with the gears on the support frame. This allows the two sets of pectoral fin assemblies, one large and one small, to operate in precise coordination through the cooperation of the gears.
[0023] Furthermore, a collar is integrally provided on the airfoil frame, and the collar is fixedly connected to the main wing rod or the wing rod.
[0024] It can be directly connected to the main wing or wing rod by means of fitting or interference fit, and is easy to assemble and disassemble.
[0025] Furthermore, from a top-down perspective, when observing the axis of the large wing rod and the axis of the wing rod, the size of the airfoil skeleton closer to the wing connection assembly is larger; the size of the airfoil skeleton farther away from the wing connection assembly is smaller.
[0026] The design is inspired by the biological morphology of manta rays. It fully utilizes biomimetic principles to minimize fluid obstruction.
[0027] Furthermore, the two inclined supports are symmetrically arranged along plane P, and from a perspective along the X direction, the shape of the two inclined supports and the mounting base as a whole is approximately "V" shaped.
[0028] The biomimetic design mimics the head fin of a manta ray. While the pectoral fins are the main source of propulsion for manta rays, the head fin design reduces head drag.
[0029] By adopting the above technical solutions, the following beneficial effects can be achieved:
[0030] 1. Through research on the propulsion mode of manta rays, the rotation of gears enables the two sets of pectoral fin components to swing back and forth, thereby achieving AUV propulsion. Compared with the traditional propeller propulsion method, it avoids the rapid rotation of the propeller and fundamentally avoids the generation of cavitation bubbles, that is, it avoids the noise caused by cavitation.
[0031] 2. A wing rod was designed, which is a further improvement on the manta ray prototype and can effectively control wingtip vortices. Attached Figure Description
[0032] Figure 1 This is a schematic diagram of the overall structure of this building;
[0033] Figure 2 This is a structural schematic diagram of the skeleton components of this structure;
[0034] Figure 3 This is a schematic diagram of the overall structure connecting the pectoral fin assembly and the body skeleton assembly;
[0035] Figure 4 This is a schematic diagram of the airfoil frame structure;
[0036] Figure 5 This is a schematic diagram of the structure after the airfoil frame is connected to the main wing shaft and the wing shaft;
[0037] Figure 6 This refers to the movement of a larger pectoral fin assembly. Figure 1 ;
[0038] Figure 7 This refers to the movement of a larger pectoral fin assembly. Figure 1 ;
[0039] Figure 8 This refers to the movement of a larger pectoral fin assembly. Figure 3 ;
[0040] Figure 9 This is a simulation diagram of the stress on the airfoil frame;
[0041] Figure 10 for Figure 6 Fluid simulation diagram under the corresponding state;
[0042] Figure 11 for Figure 7 Fluid simulation diagram under the corresponding state;
[0043] Figure 12 for Figure 8 Fluid simulation diagram under the corresponding state.
[0044] 1. Load-bearing rod; 2. Twin-wing connecting assembly; 21. Mounting base; 22. Angled bracket; 23. Stand; 24. Mounting position; 25. Gear; 3. Single-wing assembly; 30. Pivot; 31. Linkage rod; 32. Shaft one; 33. First hinge shaft; 34. Second hinge shaft; 35. Large wing rod; 36. Small wing rod; 37. Wing rod; 38. Shaft three; 39. Shaft four; 310. Airfoil frame; 311. Collar. Detailed Implementation
[0045] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.
[0046] Example 1: As Figure 1 and Figure 2 As shown, a biomimetic propulsion structure for an AUV includes a body frame assembly and two sets of pectoral fin assemblies connected to both ends of the body frame assembly.
[0047] like Figure 2 The body skeleton assembly includes the following structure:
[0048] Bearing rod 1, as the main load-bearing component of the entire propulsion structure, possesses high strength to ensure the overall structural strength. Its length direction is defined along... Figure 2 The X-direction is the forward direction of the entire propulsion structure.
[0049] Two wing-shaped connecting assemblies 2, one large and one small, are fixedly connected to both ends of the support rod 1. The end facing the X direction is larger, and the other end is smaller. Each wing-shaped connecting assembly 2 includes:
[0050] Mounting base 21 is fixedly connected to bearing rod 1 by bolts. In a top view, for ease of description, the centerline of the upper surface of mounting base 21 in the X direction is set as line L, and the surface passing through line L and along the vertical direction is set as surface P.
[0051] Two inclined brackets 22 are integrally mounted on the mounting base 21 and are symmetrically arranged along surface P for connection with the pectoral fin assembly. From a view along the X direction, the shape of the two inclined brackets 22 and the mounting base 21 as a whole is approximately "V" shaped.
[0052] Two uprights 23 are integrally mounted on the upper surface of the mounting base 21; each of the two uprights 23 is equipped with a gear 25 (see...). Figure 3 Two gears 25 are symmetrically arranged along plane P. Both gears 25 can rotate relative to the support frame 23, and their axes are parallel to the X direction. The two gears 25 mesh with each other. In practice, the two gears 25 are located in the housing. The large wing rod 35 and the small wing rod 36 (described later) need to extend out of the housing. The extension points are sealed with flexible waterproof cloth. The motor shaft (described later) also needs to extend into the housing and transmit power to the two gears 25 through the driving gear. A rubber plug is used between the motor shaft and the housing to ensure a seal, ensuring that the housing cavity is closed and that the meshing of the gears 25 is not affected by the water environment. The mounting base 21 has a reserved mounting position 24 for installing the motor. While the motor is waterproof, the driving gear connected to the motor shaft can drive one of the gears 25 to rotate actively, and the other gear 25 rotates passively through the meshing design, thereby enabling the pectoral fin assembly on the mounting base 21 to push water and achieve propulsion. The motors on both mounting bases 21 can make the meshing gears 25 rotate completely (see Figure 6 , Figure 7 and Figure 8 The pectoral fin assembly has an amplitude of approximately 60 degrees (30 degrees downward and 30 degrees upward). Furthermore, the two pectoral fin assemblies move sequentially; when the pectoral fin assembly facing forward swings downward, the other pectoral fin assembly swings upward, and vice versa, allowing the two pectoral fin assemblies to propel water in sequence. When a single pectoral fin assembly swings, the wing rod 37 swings relative to the large wing rod 35 through the cooperation of the large wing rod 35 and the small wing rod 36 (described later). The motors driving the movement of both pectoral fin assemblies are servo motors, capable of precisely controlling the speed (frequency), rotation angle, and timing to achieve precise coordination of the pectoral fin assembly movements and reciprocating swings.
[0053] The two sets of pectoral fin assemblies are designed with one large and one small size. Each set of pectoral fin assemblies contains two single-wing assemblies 3 of the same size. The large and small pectoral fin assemblies are respectively installed on the two large and small double-wing connecting assemblies 2.
[0054] In a set of pectoral fin assemblies, two single-wing assemblies 3 are respectively mounted on two inclined supports 22, and the two single-wing assemblies 3 are symmetrically arranged along surface P. For example... Figure 3 As shown, the single-wing assembly 3 includes the following structure:
[0055] Pivot 30 is rotatably connected to inclined bracket 22 via bearing, and its axis is parallel to the X direction.
[0056] Linkage rod 31 (see) Figure 3 and Figure 6 One end of the shaft is rotatably connected to the gear 25 via a shaft 32. The shaft 32 is located at a non-center position on the plane of the gear 25, and the axis of the shaft 32 is parallel to the X direction.
[0057] Both the first hinge shaft 33 and the second hinge shaft 34 are rotatably connected to the linkage rod 31, with their axes parallel to the X direction. From a perspective along the length of the linkage rod 31, the distance between the first hinge shaft 33 and the first shaft 32 is set to be relatively large, while the distance between the second hinge shaft 34 and the first shaft 32 is relatively small.
[0058] The large wing rod 35 has one end fixedly connected to the first hinge shaft 33 and can rotate relative to the linkage rod 31 through the first hinge shaft 33. The middle part of the large wing rod 35 passes through the pivot shaft 30, and the large wing rod 35 and the pivot shaft 30 are fixedly connected by an interference fit and then reinforced by adhesive.
[0059] The small wing rod 36 has one end fixedly connected to the second hinge shaft 34 and can rotate relative to the linkage rod 31 through the second hinge shaft 34.
[0060] The wing rod 37 is Y-shaped, and one end of its forked top is fixedly connected to shaft 38 (see...). Figure 6 Shaft 38 is rotatably connected to the other end of the large wing rod 35, allowing wing rod 37 to rotate relative to the large wing rod 35; the other end of the forked end is fixedly connected to shaft 4 39 (see...). Figure 6 The fourth shaft 39 is rotatably connected to the other end of the small wing rod 36, while the wing rod 37 can rotate relative to the small wing rod 36. The axes of the third shaft 38 and the fourth shaft 39 are both parallel to the X direction. From the perspective of the X direction, the first hinge shaft 33, the second hinge shaft 34, the third shaft 38, and the fourth shaft 39 form a quadrilateral structure.
[0061] Several airfoil frames 310 (see) Figure 4The airfoil frame 310 is fixedly connected to the main wing rod 35 or the wing rod 37. To facilitate the connection between the airfoil frame 310 and the main wing rod 35 or the wing rod 37, it is integrally provided with a collar 311, which is used to fit onto the middle of the main wing rod 35 or the wing rod 37 and is fixedly connected to it by an interference fit, and then further fixed by glue. When the airfoil frame 310 is arranged, the suction surface of the airfoil frame 310 faces upward and the pressure surface faces downward; the chord of the airfoil frame 310 has an angle with the horizontal plane, ensuring that when swinging downward, it will move in the X direction due to the reaction force of the water. The airfoil frames 310 have different sizes. When viewed from above along the axis of the main wing rod 35 and the wing rod 37, the airfoil frame 310 closer to the twin-wing connecting assembly 2 is larger; conversely, the airfoil frame 310 further away from the twin-wing connecting assembly 2 is smaller.
[0062] This structure also includes a waterproof fabric made of polymer materials (polyurethane) and thermoplastic elongation polymer (TPE), with a smooth surface and good tensile strength (elongation at break ≥500%) and water resistance (IPX8). It is simultaneously bonded to the surface of all airfoil frames 310 using a thermo-sealing technique. A cavity formed by a single layer of waterproof fabric simultaneously encloses all airfoil frames 310 (all airfoil frames 310 on the two sets of pectoral fin assemblies) and the steering mechanism at the tail of the structure, ensuring the cavity's airtightness. With the coordinated movement of the large wing rod 35, small wing rod 36, and wing rod 37, water propulsion is successfully completed. The waterproof fabric is analogous to the skin of a manta ray, covering all the frame structures.
[0063] The stress distribution in this design is optimized so that the main loads are located on each airfoil frame 310, and not on the surface of the waterproof fabric (see detailed stress analysis). Figure 9 Therefore, there is no need to worry about the waterproof fabric being damaged by excessive load, and the airfoil frame 310 is made of aluminum alloy. Figure 9 This indicates that under the ultimate load (simulating a manta ray, the ultimate load is 135 N / m), 2 The airfoil frame 310 showed no obvious bending deformation or damage, with a deformation rate of only about 0.05.
[0064] The principle of this structure is:
[0065] When the larger pectoral fin assembly swings upward, the smaller pectoral fin assembly swings downward; conversely, when the larger pectoral fin assembly swings downward, the smaller pectoral fin assembly swings upward. In this process, the smaller pectoral fin assembly first generates a backward pushing motion, followed by the larger pectoral fin assembly generating the same backward pushing motion. This continuous process creates a continuous pushing motion, ensuring the water flow is constantly pushed backward. According to Newton's third law, the pectoral fin assemblies receive a continuous forward reaction force, counteracting the local drag of a single pectoral fin assembly swinging upward. Furthermore, the interaction between the airfoil surface and the water flow generates lift. By designing the airfoil curvature, this lift can counteract the combined force of gravity and buoyancy in the operating environment, achieving propulsion in the X direction. Since this design does not address the AUV's steering, the steering structure is not described. All materials used in this design are corrosion-resistant.
[0066] The advantages of this structure are:
[0067] This structure is driven by fluid pressure difference, eliminating the need for high-speed rotation to cut the water flow, thus fundamentally eliminating the conditions for cavitation bubble generation and effectively reducing noise.
[0068] Example 2: In addition, the two pectoral fin components of this solution, one large and one small, and the tail steering part of this structure are three parts that can be abstractly compared to three rigid plates with variable connection relationships, with polymer waterproof material attached to their surfaces.
[0069] Figure 10 , Figure 11 and Figure 2 This scheme has three typical states (and) Figure 6 , Figure 7 and Figure 8 The surface fluid simulation diagram (corresponding to the state in the diagram).
[0070] Based on the above-described preferred embodiments of this utility model, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the technical concept of this utility model. The technical scope of this utility model is not limited to the contents of the specification, but must be determined according to the scope of the claims.
Claims
1. A bionic propulsion structure of an AUV, characterized in that, It includes a fuselage frame assembly and two sets of pectoral fin assemblies, one large and one small. The pectoral fin assemblies are located at both ends of the fuselage frame assembly. Each set of pectoral fin assemblies contains two single-wing assemblies of the same size. The single-wing assemblies of the same size are symmetrically arranged along surface P, which is a surface that is parallel to the forward direction X and along the vertical direction. The body frame components include: The support rod extends along the X direction. Two double-wing connecting assemblies are respectively installed at both ends of the support rod; the double-wing connecting assembly includes a mounting base fixedly connected to the support rod, and two inclined brackets fixedly connected to the mounting base; two uprights are fixedly connected to the mounting base, and a gear is rotatably connected to each of the two uprights, and the two gears mesh with each other; the axis of the gears is parallel to the X direction; the gears are driven to rotate by a motor. The single-wing assembly includes: The pivot is rotatably connected to the inclined support, and the axis of rotation is parallel to the X direction; The linkage is rotatably connected to the gear via shaft one. Shaft one is located at a non-center position on the plane of the gear, and the axis of shaft one is parallel to the X direction. Both the first hinge shaft and the second hinge shaft are rotatably connected to the linkage rod, and their axes are parallel to the X direction. From the perspective of the length direction of the linkage rod, the distance between the first hinge shaft and the first shaft is set to be greater, and the distance between the second hinge shaft and the first shaft is set to be closer. The large wing rod has one end fixedly connected to the first hinge axis and can rotate relative to the linkage rod through the first hinge axis; the middle part of the large wing rod passes through the pivot and is fixedly connected to the pivot axis. The small wing rod has one end fixedly connected to the second hinge shaft and can rotate relative to the linkage rod through the second hinge shaft; The wing rod is Y-shaped, with one end of its top forked end rotatably connected to the other end of the large wing rod via shaft three, and the other end of the forked end rotatably connected to the other end of the small wing rod via shaft four; the axes of shaft three and shaft four are both parallel to the X direction; Several airfoil frames are fixedly connected to the main wing shaft or wing shaft. The suction surface of the airfoil frames faces upward and the pressure surface faces downward. The chord of the airfoil frames makes an angle with the horizontal plane, ensuring that when swinging downward, a forward thrust is generated due to the reaction force of the water. This propulsion structure also includes waterproof fabric, which is heat-pressed onto the surface of the airfoil skeleton and can cover the entire airfoil skeleton.
2. The biomimetic propulsion structure for an AUV according to claim 1, characterized in that, The mounting base has a mounting position, and the motor is mounted in the mounting position.
3. The biomimetic propulsion structure for an AUV according to claim 1, characterized in that, A collar is integrally provided on the airfoil frame, and the collar is fixedly connected to the main wing rod or the wing rod.
4. The biomimetic propulsion structure for an AUV according to claim 1, characterized in that, From a top-down perspective, the axis of the main wing shaft coincides with the axis of the wing shaft. When viewed along both axes, the closer to the biplane connection assembly, the larger the size of the airfoil frame; the farther away from the biplane connection assembly, the smaller the size of the airfoil frame.
5. The biomimetic propulsion structure for an AUV according to claim 1, characterized in that, The two inclined supports are symmetrically arranged along plane P. From the perspective of the X direction, the two inclined supports and the mounting base form an integral shape that is approximately "V".