A self-sustaining, low-power, long-endurance unmanned underwater vehicle

Abstract

This application discloses a self-sustaining, low-power, long-endurance unmanned underwater vehicle (UUV). In this technical solution, the UUV propels itself forward by underwater gliding. During underwater gliding, the effective angle of attack is small, and drag is low, making it a low-energy propulsion method; a small altitude difference can achieve a large propulsion distance. There is no mass exchange between the UUV and its surroundings, and its own weight remains essentially constant, reducing the possibility of water leakage. Furthermore, the expansion joint itself is elastic, capable of storing the compressive energy of the surrounding fluid, reducing its own energy consumption. The UUV utilizes different flapping fin positions and angles of attack to achieve forward and backward maneuvers during buoyancy, providing greater flexibility. The UUV only consumes electrical energy when the electric motor is operating; it consumes no energy for most of the gliding process. The electrical energy can be derived from the fluid energy of the surrounding water flow, allowing the UUV to achieve ultra-long endurance.

Description

Technical Field

[0001] This application relates to the technical field of unmanned underwater vehicles, and more particularly to a self-sustaining, low-power, long-endurance unmanned underwater vehicle. Background Technology

[0002] As an important member of unmanned platforms, unmanned underwater vehicles (UUVs) are currently used in fields such as intelligence reconnaissance, anti-submarine warfare and mine countermeasures, marine surveys, seabed topography surveys, and marine hydrological monitoring.

[0003] Unmanned underwater vehicles (UUVs) are characterized by low cost, flexible use, strong stealth capabilities, adaptability to complex sea conditions, and effective avoidance of personnel casualties, making them a widely applicable force multiplier at sea. UUVs are typically deployed from submarines, surface ships, or civilian vessels, and are categorized into remotely controlled and autonomous types, with fully autonomous UUVs representing the future trend.

[0004] Unmanned underwater vehicles (UUVs) have the following advantages: 1) Small size, with very small side and frontal cross-sectional areas, making them difficult to detect with active sonar. 2) Low self-noise, good acoustic concealment, making them difficult to detect with passive sonar. With the development of technologies such as artificial intelligence and underwater communication, the intelligence level of UUVs will continue to improve, enabling them to interact with the environment and effectively detect and identify underwater targets, collect samples, or perform complex tasks that are beyond human capabilities. However, most UUVs currently rely on batteries for power, and the energy density of batteries at present cannot support long-distance, long-duration travel. Most UUVs can only travel at speeds of 4 to 5 knots or even lower, and must return to the nearest port or ship at sea to recharge before their power runs out. This limits their operational range and increases the likelihood of them being detected by the enemy.

[0005] Flapping oscillations are widespread in nature. Birds, insects, fish, and marine organisms such as whales and dolphins use the flapping oscillations of their wings or fins to generate lift and thrust for locomotion. Insects were among the first organisms to evolve active flight capabilities, and their maneuverability remains unmatched by other organisms or man-made aircraft. Theoretical research shows that flapping wing propulsion is significantly more efficient than conventional propulsion systems, reaching up to 85%, demonstrating excellent aerodynamic and hydrodynamic performance. Due to its significant performance advantages and broad application prospects, flapping-wing-inspired robots have become a research hotspot for novel underwater robots. The excellent hydrodynamic performance of flapping wing propulsion has inspired researchers to mimic the buoyancy and pitching motion of flapping wings to harvest fluid energy. After more than 20 years of development, the energy harvesting efficiency of flapping wings has increased from 28% to 40%, and the movement mode of flapping wings has evolved from active to fully passive. In fact, large birds often utilize both flapping wing propulsion and energy harvesting simultaneously during flight. The inspiration from large birds for the design of unmanned underwater vehicles lies in using a gliding posture to complete most of the propulsion process. This is because the effective angle of attack is small and the drag is low during gliding, which is a low-loss propulsion method. A small height difference can achieve a large distance of propulsion, and the gravitational potential energy consumed by gliding can be converted into the kinetic energy of the Shanghai sea current.

[0006] This invention proposes a novel unmanned underwater vehicle (UUV) that can glide dynamically with low or even zero power consumption by utilizing the kinetic energy of surrounding fluids during propulsion, similar to large birds. Simultaneously, it can also rely on its own energy to create elevation differences through alterations in gravity / buoyancy, enabling low-power gliding. This UUV can solve the problem of real-time oceanographic information acquisition, a fundamental condition for research in areas such as ocean energy resource assessment and climate change. Furthermore, this low-power, long-range UUV can also be applied to geological mapping, resource exploration, and environmental monitoring. Summary of the Invention

[0007] In view of this, this application provides a self-sustaining, low-power, long-endurance unmanned underwater vehicle that can achieve low-power, long-distance cruising by utilizing flapping wing dynamic gliding.

[0008] This application provides a self-sustaining, low-power, long-endurance unmanned underwater vehicle, comprising:

[0009] The movable covers are linearly and movably installed at the front and rear ends of the fixed outer shell to form a deformable sealed cavity with the fixed outer shell;

[0010] Linear drive mechanisms are used to drive the linear movement of the movable cover, so as to change the volume of the deformable sealing cavity and generate a driving force for sinking or floating.

[0011] The flapping wings extend from both sides of the fixed sealing cavity surrounded by the fixed outer shell;

[0012] A swing drive mechanism is used to drive the flapping wing to swing so as to change the angle of attack of the flapping wing, thereby generating a forward or backward driving force.

[0013] Optionally, the linear drive mechanism includes a stepper motor and a screw assembly, wherein the screw assembly is fixedly connected to the movable cover and the stepper motor respectively, and the screw assembly is used to generate linear power under the rotational power input of the stepper motor.

[0014] Optionally, the movable cover is fixed to the fixed outer shell by an expansion joint.

[0015] Optionally, the outer surface of the active cover is configured to be streamlined.

[0016] Optionally, the swing drive mechanism includes a drive motor and a crankshaft, with the crankshaft fixedly connected to the drive motor and the flapping wing respectively.

[0017] Optionally, the connection between the drive motor and the crankshaft is sealed with insulating oil, and the drive motor and the crankshaft are separated into different sealed cavities.

[0018] Optionally, the end of the flapping wing is fixed with a wing tip plate.

[0019] Optionally, it also includes an electrically connected battery and a power generation mechanism, the power generation mechanism being used to convert the mechanical energy of the flapping wings driven by the water flow into electrical energy, and the battery being used to store the electrical energy.

[0020] Optionally, the battery is located at the bottom of the fixed sealed cavity.

[0021] Compared with the prior art, this application has the following beneficial effects:

[0022] 1. Submarines propel themselves by gliding underwater. Underwater gliding involves a small effective angle of attack and low drag, making it a low-energy propulsion method. A relatively small altitude difference can achieve a large propulsion distance. Submarines utilize gravitational potential energy and buoyancy potential energy for propulsion during descent and ascent, respectively, achieving uninterrupted underwater gliding propulsion.

[0023] 2. This application utilizes an expansion joint to mimic the buoyancy of fish by changing their own volume. Since there is no mass exchange between the submersible and its surroundings, its own weight remains essentially constant, reducing the possibility of leakage. Furthermore, the expansion joint itself is elastic, allowing it to store the compressive energy of the external fluid, thus reducing its own energy consumption.

[0024] 3. The submersible utilizes the different positions and angles of attack of its flapping wings to achieve forward and backward maneuvers during the buoyancy process, thus possessing greater flexibility.

[0025] 4. The submersible only consumes electrical energy when the electric motor is working. It does not consume energy for most of the time during gliding. The electrical energy can come from the fluid energy of the surrounding water flow. The submersible achieves ultra-long endurance by utilizing the fluid energy of the water flow. Attached Figure Description

[0026] The technical solution and other beneficial effects of this application will become apparent from the following detailed description of specific embodiments in conjunction with the accompanying drawings.

[0027] Figure 1 This is a schematic diagram of the overall structure of the self-sustaining, low-power, long-endurance unmanned underwater vehicle provided in the embodiments of this application.

[0028] Figure 2 This is a schematic diagram illustrating the working state of the self-sustaining, low-power, long-endurance unmanned underwater vehicle provided in this application embodiment.

[0029] Figure 3 This is a schematic diagram illustrating the effect of water flow on a self-sustaining, low-power, long-endurance unmanned underwater vehicle provided in an embodiment of this application.

[0030] The components in the diagram are labeled as follows:

[0031] 1-Deformable sealing cavity; 2-Fixed sealing cavity; 3-Expansion joint; 4-Fixed outer shell; 5-Movable cover; 7-Screw; 9-Stepper motor; 11-Drive motor; 13-Crankshaft; 15-Flapping wing; 17-Submersible axis; 18-Battery; 19-Wing tip plate. Detailed Implementation

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

[0033] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0034] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" 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, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0035] The following disclosure provides many different embodiments or examples for implementing different structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. Of course, these are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, various specific examples of processes and materials are provided in this application, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0036] Please see Figure 1 The self-sustaining, low-power, long-endurance unmanned underwater vehicle according to embodiments of this application includes:

[0037] The movable cover 5 is linearly and movably installed at the front and rear ends of the fixed outer shell 4 to form a deformable sealing cavity 1 with the fixed outer shell 4.

[0038] Linear drive mechanisms are used to drive the linear movement of the aforementioned movable cover 5, so as to change the volume of the deformable sealing cavity 1 and generate a driving force for sinking or floating.

[0039] The flapping wings 15 extend from two sides of the fixed sealing cavity 2 surrounded by the fixed outer shell 4;

[0040] The swing drive mechanism is used to drive the flapping wing 15 to swing so that the angle of attack of the flapping wing 15 changes, thereby generating a forward or backward driving force.

[0041] The statement "the change in volume of the deformable sealing cavity 1 creates the driving force for sinking or surfacing" can be understood as follows: when the volume of the deformable sealing cavity 1 decreases, the buoyancy decreases; when the volume of the deformable sealing cavity 1 increases, the buoyancy increases. When the buoyancy of the submersible decreases to less than its own weight, the submersible will sink; when the buoyancy of the submersible increases to greater than its own weight, the submersible will surface.

[0042] The statement "the flapping wing 15 oscillates to change its angle of attack, creating a forward or backward driving force" can be understood as follows: the flapping wing 15 maintains a positive or negative angle of attack during descent and ascent. During descent, when the flapping wing 15 maintains a negative angle of attack, the horizontal hydrodynamic force exerted by the water flow propels the submersible forward; when the flapping wing 15 maintains a positive angle of attack, the horizontal hydrodynamic force exerted by the water flow propels the submersible backward. During ascent, when the flapping wing 15 maintains a negative angle of attack, the horizontal hydrodynamic force exerted by the water flow propels the submersible backward; when the flapping wing 15 maintains a negative angle of attack, the horizontal hydrodynamic force exerted by the water flow propels the submersible forward.

[0043] The term "angle of attack of flapping wing 15" here refers to the misalignment of the pitch center of flapping wing 15 with the drive shaft axis. A 360° rotation of the pitch center will change the angle of attack of flapping wing 15.

[0044] The flapping wing 15 and the linear extension and retraction of the movable cover 5 can form different combined working states. Specifically, the flapping wing 15 can change the position of the submersible's center of gravity, and the magnitude of the change in the center of gravity position is determined by the distance from the pitch center to the drive shaft axis. When the flapping wing 15 is located in the lower and rear part of the submersible, the nose expansion joint 3 retracts, the buoyancy of the submersible decreases, and the center of buoyancy shifts to the left, causing the front half of the submersible to become heavier. The nose of the submersible sinks relative to the tail of the submersible until the center of gravity and the center of buoyancy of the submersible are repositioned to be on the same vertical line, reaching a new equilibrium. At this point, the negative angle of attack of flapping wing 15 causes the submersible to generate forward thrust during descent; when flapping wing 15 is located at the lower front of the submersible, the nose expansion joint 3 extends, the submersible's buoyancy decreases, and the center of buoyancy shifts to the right, making the rear half of the submersible heavier, causing the submersible's nose to rise relative to the tail, and the positive angle of attack of flapping wing 15 causes forward thrust during ascent; when flapping wing 15 is located at the upper front of the submersible, the tail expansion joint 3 extends, the submersible's buoyancy increases, and the center of buoyancy shifts to the left, similarly causing the submersible's nose to sink relative to the tail, and the positive angle of attack of flapping wing 15 causes forward thrust during ascent; when flapping wing 15 is located at the upper rear of the submersible, the submersible's buoyancy decreases, and the center of buoyancy shifts to the right, similarly causing the submersible's nose to rise relative to the tail, and the positive angle of attack of flapping wing 15 causes forward thrust during descent. In summary, the flapping of the flapping wing 15 can control the direction of movement of the submersible, and the extension and retraction of the movable cover 5 can control the pitch and buoyancy of the flapping wing 15, so as to reduce the surface area and drag of the submersible during its movement.

[0045] Taking flapping wing 15 as an example to illustrate the different motions at the position of flapping wing 15, please refer to [link / reference]. Figure 2In state A, when flapping wing 15 is located at the lower rear of the submersible, expansion joint 3 retracts, reducing the submersible's buoyancy and shifting the center of buoyancy to the left. This causes the front half of the submersible to become heavier (right side is the forward direction, left side is the reverse direction), and the submersible's nose sinks relative to the tail until the submersible's center of gravity and center of buoyancy are aligned on the same vertical line again, achieving a new equilibrium. At this point, the negative angle of attack of flapping wing 15 causes the submersible to generate the previous thrust during the sinking process.

[0046] Please see Figure 2 In state B, when flapping wing 15 is located at the lower front part of the submersible, expansion joint 3 extends, the buoyancy of the submersible decreases, the center of buoyancy shifts to the right, resulting in the rear half of the submersible being heavier, the head of the submersible lifting relative to the tail of the submersible, and the positive angle of attack of flapping wing 15 causing the submersible to generate forward thrust during the ascent process.

[0047] Please see Figure 2 In state C, when flapping wing 15 is located at the upper front part of the submersible, expansion joint 3 extends, the buoyancy of the submersible increases, the center of buoyancy shifts to the left, which also causes the head of the submersible to sink relative to the tail of the submersible. The rearward positive angle of attack of flapping wing 15 causes the submersible to have forward and backward thrust during the ascent process.

[0048] Please see Figure 2 In state D, when the flapping wing 15 is located at the upper rear of the submersible, the expansion joint 3 retracts, reducing the submersible's buoyancy and shifting its center of buoyancy to the right. This also causes the submersible's nose to rise relative to its tail. The positive angle of attack of the flapping wing 15 results in thrust in different directions during the submersible's descent. In summary, the flapping of the flapping wing 15 provides the submersible with propulsion in different directions, enabling a certain degree of maneuverability. The two expansion joints 3 work together to control the submersible's pitch angle, ensuring that the submersible's axis 17 is always aligned with its direction of motion, thereby reducing drag during gliding. The stepper motors 9 and 9 can operate independently, adjusting the submersible's center of gravity and the angle of attack of the flapping wing 15 while controlling the submersible's yaw angle. When the angle of attack of the flapping wing 15 is greater than that of the flapping wing 15, the forward driving force of the flapping wing 15 is also greater than that of the flapping wing 15, and the submersible will yaw towards the side of the flapping wing 15; conversely, it will yaw towards the side of the flapping wing 15 if the angle of attack of the flapping wing 15 is less than that of the flapping wing 15.

[0049] In some embodiments, the movable cover 5 is fixed to the fixed housing 4 by an expansion joint 3.

[0050] The design considerations for the expansion joint 3 are as follows: the expansion joint 3 itself has a certain degree of elasticity, which can store the compression work applied by the external fluid during the sinking process and release it during the buoyancy process, thereby reducing the energy consumption within a sinking and buoyancy cycle.

[0051] The aforementioned deformable sealing cavity 1 and fixed sealing cavity 2 are located on the underwater vehicle as follows: The underwater vehicle has two sealing cavities. The two large sealing cavities, namely the deformable sealing cavity 1, are located at the tail end, while the small sealing cavity enclosed by the fixed outer shell 4 in the middle is the fixed sealing cavity 2. Each of the two deformable sealing cavities 1 is equipped with an expansion joint 3, which is fixedly connected to the aforementioned movable cover 5.

[0052] The expansion joint 3 can be welded to the deformable sealing cavity 1 of the submersible, forming a completely sealed cavity and reducing the risk of air leakage.

[0053] As one exemplary implementation of the outer surface of the movable cover 5, it is configured in a streamlined shape. The movable cover 5 is machined into a streamlined shape to reduce flow resistance.

[0054] As an exemplary implementation of a linear drive mechanism, it includes a stepper motor 9 and a screw 7 assembly, the screw 7 assembly being fixedly connected to the movable cover 5 and the stepper motor 9 respectively, the screw 7 assembly being used to generate linear power under the rotational power input of the stepper motor 9.

[0055] The movable cover 5 is interconnected with a stepper motor 9. The screw 7 and the stepper motor 9 form a through-type linear motor, driving the movable cover 5 to move in a straight line. Taking the stepper motor 9 as an example, we can explain how the stepper motor 9 controls the volume of the deformable sealing cavity 1 of the submersible. When the stepper motor 9 rotates forward, it drives the screw 7 and the movable cover 5 to move to the left, thereby causing the expansion joint 3 to contract, and the volume of the deformable sealing cavity 1 of the submersible decreases. When the stepper motor 9 rotates in reverse, it drives the screw 7 and the movable cover 5 to move to the right, thereby causing the expansion joint 3 to extend, and the volume of the deformable sealing cavity 1 of the submersible increases. The change in the volume of the deformable sealing cavity 1 of the submersible will cause a change in its buoyancy. When the buoyancy of the submersible decreases to less than its own weight, the submersible will sink; when the buoyancy of the submersible increases to more than its own weight, the submersible will rise. The expansion joint 3 itself has a certain degree of elasticity. During the descent, the water pressure gradually increases, compressing the deformable cavity to reduce its volume and doing work on the cavity. The expansion joint 3 stores the compression work applied by the external fluid using its elastic potential energy and releases it during the ascent, reducing energy consumption within a single buoyancy cycle. The stepper motor 9 only operates at the highest and lowest positions during the buoyancy process, remaining inactive for most of the time to minimize power consumption. The stepper motors 9 and 9 can operate independently, adjusting the submersible's buoyancy and center of gravity simultaneously.

[0056] As an exemplary implementation of the oscillating drive mechanism, it includes a drive motor and a crankshaft 13, wherein the crankshaft 13 is fixedly connected to the drive motor and the flapping wing 15 respectively.

[0057] Here, the use of crankshaft 13 causes the pitch center of flapping wing 15 to not coincide with the axis of the motor, forming a oscillating component. The rotation of crankshaft 13 will cause the pitch center of flapping wing 15 to rotate arbitrarily, while changing the angle of attack of flapping wing 15. Crankshaft 13 can be formed by a drive shaft and a telescopic rod fixedly connected together, and the drive shaft is fixedly connected to the power output shaft of the drive motor.

[0058] The drive motor can be located inside the fixed sealed cavity 2. The connection between the drive motor and the crankshaft 13 is sealed with insulating oil. The drive motor and the crankshaft 13 are separated into different sealed cavities, thus preventing external water from entering the sealed chamber.

[0059] In some embodiments, the submersible further includes an electrically connected battery 18 and a power generation mechanism. The power generation mechanism converts the mechanical energy of the flapping fins 15 driven by water flow into electrical energy, and the battery 18 stores the electrical energy. Thus, the motor can function as both a motor and a generator. When water flow is present around the submersible, the motor enters generator mode, and the flapping fins 15 reciprocate under the combined action of the water flow and their own buoyancy, thereby generating electricity and storing it in the battery 18.

[0060] Specifically, please refer to Figure 3 When the submersible is anchored or otherwise secured in the water flow, the expansion joint 3 extends to its maximum length and then retracts to its minimum length. At this time, the flapping fin 15 maintains a large angle of attack, and the water flow cannot adhere to the surface of the flapping fin 15, resulting in periodic flow separation. The periodic shedding vortices drive the pitching motion, thereby driving the motor to generate electricity, which is then stored in the battery 18. By converting the fluid energy in the ambient water flow into electrical energy, the submersible of this invention can achieve underwater self-sustaining, low-power, long-endurance operation.

[0061] The submersible's battery 18 can be located at the bottom of the fixed sealed cavity 2, ensuring that the submersible's center of buoyancy is always located above the center of gravity, thus improving the submersible's stability in the pitch and roll directions.

[0062] In some embodiments, wingtip plates 19 are installed at the wingtips of the flapping wing 15, thereby improving the stability of the submersible's yaw direction, reducing the flow around the tip of the flapping wing 15, and enhancing the propulsion performance of the flapping wing 15. When there is water flow around the submersible, the water flow can act on the flapping wing 15 to generate electricity from the power generation components.

[0063] The above description is merely a preferred embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A self-sustaining, low-power, long-endurance unmanned underwater vehicle, characterized in that, include: The movable covers are linearly and movably installed at the front and rear ends of the fixed outer shell to form a deformable sealed cavity with the fixed outer shell; Linear drive mechanisms are used to drive the linear movement of the movable cover, so as to change the volume of the deformable sealing cavity and generate a driving force for sinking or floating. The flapping wings extend from both sides of the fixed sealing cavity surrounded by the fixed outer shell; A swing drive mechanism is used to drive the flapping wing to swing so as to change the angle of attack of the flapping wing, thereby generating a forward or backward driving force; the swing drive mechanism includes a drive motor and a crankshaft, the crankshaft is fixed to the drive motor and the flapping wing respectively, and the crankshaft makes the pitch center of the flapping wing not coincide with the axis of the drive motor.

2. The self-sustaining, low-power, long-endurance unmanned underwater vehicle according to claim 1, characterized in that, The linear drive mechanism includes a stepper motor and a screw assembly. The screw assembly is fixedly connected to the movable cover and the stepper motor respectively. The screw assembly is used to generate linear power under the rotational power input of the stepper motor.

3. The self-sustaining, low-power, long-endurance unmanned underwater vehicle according to claim 1, characterized in that, The movable cover is fixed to the fixed outer shell by an expansion joint.

4. The self-sustaining, low-power, long-endurance unmanned underwater vehicle according to claim 1, characterized in that, The outer surface of the movable cover is configured in a streamlined shape.

5. The self-sustaining, low-power, long-endurance unmanned underwater vehicle according to claim 1, characterized in that, The connection between the drive motor and the crankshaft is sealed with insulating oil, and the drive motor and the crankshaft are separated into different sealed cavities.

6. The self-sustaining, low-power, long-endurance unmanned underwater vehicle according to claim 1, characterized in that, The flapping wing is fixed with a wing end plate at its end.

7. The self-sustaining, low-power, long-endurance unmanned underwater vehicle according to claim 1, characterized in that, It also includes an electrically connected battery and a power generation mechanism, the power generation mechanism being used to convert the mechanical energy of the flapping wings driven by the water flow into electrical energy, and the battery being used to store the electrical energy.

8. The self-sustaining, low-power, long-endurance unmanned underwater vehicle according to claim 7, characterized in that, The battery is located at the bottom of the fixed sealed cavity.

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