Multi-degree-of-freedom passive vibration and attitude stabilization device for deep-sea buoy

Abstract

The application relates to a buoy technical field, in particular to a multi-degree-of-freedom passive damping and attitude stabilizing device for a deep-sea buoy, which comprises a buoyancy main body arranged above an anchorage and an anchor cable, the buoyancy main body is a double-sphere structure symmetrical in up-down direction, and a waist-shaped neck structure is arranged between the two spheres; a heave damping device is arranged in the waist-shaped neck structure and is used for bearing the static load tension of the anchor cable and providing buffer stiffness; under the action of horizontal sea current, the spheres on the upper side and the lower side of the buoyancy main body deflect around the overall gravity center of the buoyancy main body, and under the blocking action of the anchor cable on the sphere on the lower side, the spheres on the upper side and the lower side generate moments with opposite directions around the waist-shaped neck structure, so as to passively offset the overturning moment. The mooring point is arranged at the waist by arranging the double-sphere structure symmetrical in up-down direction, the fluid resistance of the spheres on the upper side and the lower side forms moments with opposite directions around the mooring point and offsets each other, and the overturning moment caused by the sea current is weakened in the structural principle; the device is obviously superior to the traditional single-sphere or streamline shell scheme.

Description

Technical Field

[0001] This invention relates to the field of buoy technology, specifically to a multi-degree-of-freedom passive vibration reduction and attitude stabilization device for deep-sea moorings. Background Technology

[0002] Submarine mooring systems are essential equipment for marine environmental monitoring, underwater target detection, and marine scientific research. They typically consist of an anchor, anchor cable, main buoy, and mounted instruments, and are deployed at a predetermined depth underwater for long-term observation operations. The underwater attitude and stress conditions of the mooring system directly affect its operational performance—the tilting of the main buoy can cause the mounted instruments to deviate from the intended measurement direction, the torsional oscillation of the cable can interfere with the pointing accuracy of the vector sensor, and the heave disturbance transmitted by surface waves through the mooring cable can introduce measurement noise.

[0003] Existing research indicates that underwater mooring systems are subject to three main types of disturbances: ocean current resistance is the primary cause of mooring tilt and horizontal deviation; the greater the current velocity, the greater the horizontal distance between the main buoy and the anchor point, and the larger the system tilt angle. Cable torque originates from the torsion generated by the flexible cable during deployment and operation, which causes the mooring to rotate and oscillate periodically along its vertical axis, interfering with the measurement accuracy of the directional sensors. Surface wave disturbances are transmitted to the underwater system through the surface marker buoy, exacerbating vibrations in the plumb bob direction and fluctuations in the node position.

[0004] To address the aforementioned problems, numerous technical solutions have been proposed. Patent application CN200810139948.X discloses a mooring device that improves the moor's attitude and prevents entanglement through a combination of rubber cable and weights. Patent application CN201410317038.1 discloses a moor attitude adjustment device that actively adjusts the center of gravity position through a controller and an oil extraction system to achieve attitude adjustment. However, these solutions either involve active control, requiring energy consumption, or only isolate a single degree of freedom, such as heave or yaw, lacking a purely passive, comprehensive solution that can simultaneously address tilt, torsional oscillation, and heave coupling problems.

[0005] To address the shortcomings of the existing technologies, this invention proposes a multi-degree-of-freedom passive vibration reduction and attitude stabilization device for deep-sea moorings. Summary of the Invention

[0006] Existing underwater moorings typically employ a single sphere or cylindrical structure for their main buoy, with the mooring point usually located at the bottom. Under the influence of ocean currents, fluid resistance acts at the center of the sphere, while the mooring restraint is located at the bottom, resulting in a large lever arm and a significant overturning moment. This causes the mooring body to tilt continuously as the current velocity increases. Even with a streamlined hull to reduce resistance, the lever arm structure of the overturning moment remains unchanged, and the tilting problem cannot be fundamentally solved. To overcome the shortcomings of the prior art, the present invention aims to provide a multi-degree-of-freedom passive vibration reduction and attitude stabilization device for deep-sea underwater moorings, thereby addressing the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides a multi-degree-of-freedom passive vibration reduction and attitude stabilization device for deep-sea moorings, including a buoyancy body disposed above the mooring and anchor cable, the buoyancy body having a double-sphere structure with vertical symmetry and a waist-shaped constriction structure disposed between the double spheres; A heave damping device is disposed inside the waist-shaped necking structure for connecting to the upper end of the anchor cable, and the overall center of gravity of the device is vertically positioned below the waist-shaped necking structure; the heave damping device includes an elastic body for bearing the static load tension of the anchor cable and providing buffer stiffness. A hydraulic damping component, comprising a cylinder filled with a high-viscosity damping fluid and a pair of pistons and sleeves coaxially and fixedly connected to an elastomer, is used to convert the kinetic energy of the overall heave motion into heat energy through viscous damping motion. Under the action of horizontal ocean currents, the spheres above and below the buoyancy body deflect around its overall center of gravity. Under the obstruction of the anchor cable on the lower sphere, the upper and lower spheres generate torques in opposite directions around the waist-shaped constriction structure to passively counteract the overturning torque.

[0008] As a further improvement to this technical solution, the waist-shaped constriction structure is integrally formed and connected to the top of the lower float, and the buoyancy body is composed of the upper float and the waist-shaped constriction structure being detachably and fixedly connected. A counterweight is installed on the inner wall of the bottom of the lower float to increase the vertical floating stability of the buoyancy body.

[0009] As a further improvement to this technical solution, the upper and lower floating balls are both divided into upper and lower hemispherical shells and fixedly connected to form a sphere. The central axis of the lower floating ball is provided with a cylindrical channel structure, and the channel hole passes through the upper and lower ends of the central axis of the lower floating ball.

[0010] As a further improvement to this technical solution, the waist-shaped constriction structure is integrally formed and connected to the top of the lower float, and is detachably and fixedly connected to the bottom of the upper float.

[0011] As a further improvement to this technical solution, the elastomer is made of titanium-nickel alloy, the cylinder is fixedly sleeved on the top of the cylindrical channel structure, a pair of pistons are sealed and slidably sleeved with the cylinder, and a pair of sleeves are sealed and slidably sleeved with the cylinder caps at the upper and lower ends of the cylinder.

[0012] As a further improvement to this technical solution, the upper end of the anchor cable is fixedly sleeved inside the lower sleeve, and a bearing is coaxially connected to the upper sleeve through a limiting head, and the bearing is fixedly sleeved in the central groove at the bottom of the upper float; then the anchor cable can rotate freely relative to the buoyancy body around the vertical axis of the device to release the cable torque.

[0013] As a further improvement to this technical solution, the damping coefficient of the hydraulic damping component is set to 0.7 to 1.0 times the critical damping.

[0014] As a further improvement to this technical solution, a multi-dimensional damping mechanism is provided on the outer periphery of the bottom of the lower float. The multi-dimensional damping mechanism consists of several sets of porous damping discs that flip longitudinally and laterally, which are used to increase fluid damping in the pitch and roll directions.

[0015] As a further improvement to this technical solution, the multidimensional damping mechanism includes a mounting component adapted to be snapped onto the bottom of the lower float, a plurality of pitch damping plates hinged to the upper port of the mounting component, and a plurality of roll damping plates hinged to the arc sidewall of the mounting component.

[0016] As a further improvement to this technical solution, both the upper and lower buoys are integrally formed from pressure-resistant composite materials and filled with low-density buoyancy material.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This multi-degree-of-freedom passive vibration reduction and attitude stabilization device for deep-sea moorings uses a symmetrical double-sphere structure with the mooring point at the waist. This causes the fluid resistance on the upper and lower spheres to generate opposing torques around the mooring point, which cancel each other out. This structural principle weakens the overturning moment caused by ocean currents. This mechanism allows the buoy to maintain a vertical attitude even under high current conditions, which is significantly better than traditional single-sphere or streamlined shell solutions.

[0018] 2. This multi-degree-of-freedom passive vibration reduction and attitude stabilization device for deep-sea moorings is designed with a gourd-shaped buoyancy body to place the center of gravity below the mooring point. It utilizes gravity and buoyancy to automatically generate a restoring torque, making the vertical state the only stable equilibrium state of the system, and achieving attitude self-stabilization without active control.

[0019] 3. This multi-degree-of-freedom passive vibration reduction and attitude stabilization device for deep-sea moorings isolates attitude disturbances in the pitch / roll direction through a gyroscope and attenuates wave transmission in the heave direction through a composite heave damping device. It works in concert with each other for different degrees of freedom without interfering with each other, thus achieving comprehensive passive suppression of ocean current tilt angle, cable torsional vibration and surface wave disturbance.

[0020] 4. This multi-degree-of-freedom passive vibration reduction and attitude stabilization device for deep-sea moorings operates on a purely passive principle, requiring no external energy input and lacking electronic components such as sensors, controllers, and actuators. It is suitable for deep-sea high-pressure and long-term deployment applications, and has extremely high reliability and maintenance-free operation. Attached Figure Description

[0021] The accompanying drawings described herein are for illustrative purposes only. The shapes and proportions of the components in the drawings are merely schematic and intended to aid in understanding the invention. They are not intended to specifically limit the shapes and proportions of the components of the invention.

[0022] Figure 1 This is a schematic diagram of the overall assembly structure of the present invention; Figure 2 For the present invention Figure 1 Front view; Figure 3 This is a schematic diagram of the internal assembly structure of the buoyancy body of the present invention; Figure 4 For the present invention Figure 3 Front view; Figure 5 This is a schematic diagram of the assembly structure of the heave damping device and multidimensional damping mechanism of the present invention. Figure 6 This is an exploded view of the heave damping device of the present invention; Figure 7 This is a schematic diagram of the assembly structure of the cylinder and mounting parts of the present invention; The meanings of the labels in the diagram are as follows: 100. Anchoring; 200. Anchor cable; 210. Bearing; 220. Limiting head; 300. Buoyancy main body; 310. Upper buoy; 320. Lower buoy; 330. Waist-shaped constricted neck structure; 400. Heave damping device; 410. Cylinder; 420. Sleeve; 430. Piston; 431. Throttling orifice; 440. Elastomer; 500. Multidimensional damping mechanism; 510. Twist damping plate; 520. Roll damping plate; 530. Mounting component; 531. Lateral hinge sleeve; 532. Longitudinal hinge sleeve. Detailed Implementation

[0023] Under the guidance of this invention, any possible variations of this invention by those skilled in the art should be considered within its scope. The directional terms used herein are based on the orientations shown in the accompanying drawings for ease of description and simplification, and should not be construed as limiting the invention. Furthermore, in the description of this invention, "a number" means two or more, unless otherwise explicitly specified.

[0024] Please see Figures 1-7 As shown, the present invention provides a multi-degree-of-freedom passive vibration reduction and attitude stabilization device for deep-sea moorings, including a buoyancy body 300 disposed above the mooring 100 and the anchor cable 200. The buoyancy body 300 has a double-sphere structure with vertical symmetry and a waist-shaped constriction structure 330 disposed between the two spheres. The heave damping device 400 is disposed inside the waist-shaped necking structure 330 and is used to connect to the upper end of the anchor cable 200. The overall center of gravity of the device is set below the waist-shaped necking structure 330 in the vertical direction. The heave damping device 400 includes an elastic body 440 for bearing the static load tension of the anchor cable 200 and providing buffer stiffness. The hydraulic damping component includes a cylinder 410 filled with high-viscosity damping fluid and a pair of pistons 430 and sleeves 420 coaxially and fixedly connected to an elastic body 440. It is used to convert the kinetic energy of the overall heave motion into heat energy through viscous damping motion, thereby playing a vibration reduction role. Under the action of horizontal ocean currents, the spheres above and below the buoyancy body 300 deflect around its overall center of gravity. With the obstruction of the anchor cable 200 on the lower sphere, plus the resistance of the seawater, the upper and lower spheres generate torques in opposite directions around the waist-shaped constriction structure 330, which passively counteract the overturning torque and are in a multi-degree-of-freedom counteracting state.

[0025] Specifically, the waist-shaped constriction structure 330 is integrally formed and connected to the top of the lower float 320. The buoyancy body 300 is composed of an upper float 310 and a waist-shaped constriction structure 330 that are detachably and fixedly connected. The waist-shaped constriction structure 330 is detachably and fixedly connected to the bottom of the upper float, such as by a threaded connection or by a pin penetrating the side wall. A counterweight is installed on the inner wall of the bottom of the lower float 320 to increase the vertical floating stability of the buoyancy body 300, making the overall center of gravity of the device 80-100mm below the geometric center of the waist-shaped constriction structure 330. This offset center of gravity design ensures the vertical stability of the buoyancy body 300 in the water. When the buoyancy body 300 tilts, gravity and buoyancy form a restoring torque, forcing it to return to its upright position, similar to the principle of a roly-poly toy.

[0026] Furthermore, both the upper float 310 and the lower float 320 are divided into upper and lower hemispherical shells and fixedly connected to form a sphere. The lower float 320 has a cylindrical channel structure along its central axis, with the channel hole penetrating both the upper and lower ends of the central axis. Both the upper and lower hemispherical shells of the upper float 310 and the lower float 320 are integrally molded from pressure-resistant composite materials and filled with low-density buoyancy materials, such as hollow glass microsphere composite foam. Figure 3 and Figure 4As shown, since the upper float 310 houses a gyroscope and the lower float 320 has a cylindrical channel structure, they need to be manufactured in two halves for installation. The upper float 310 is a sphere composed of two hemispherical shells, both with the same diameter of 800mm. The lower float 320 is also a sphere composed of two hemispherical shells, both with the same diameter of 800mm. The minimum diameter of the waist-shaped constriction structure 330 between the upper float 310 and the lower float 320 is 300mm, and the net buoyancy is designed to be 500kg. Through holes are provided in the solid part of the waist-shaped constriction structure 330, penetrating the spherical cavity, for passing signal cables or power cables to achieve electrical connection with the instruments below.

[0027] Furthermore, the upper buoy 310 is equipped with a gyroscope, which is rotatably connected to the inner wall of the upper buoy 310 through at least two orthogonal horizontal axes, and is used to carry measuring instruments, such as vector hydrophones or attitude sensors; when the buoyancy body 300 tilts under the action of ocean currents, the gyroscope and the measuring instruments it carries always maintain a vertical attitude under the action of gravity.

[0028] The gyroscope comprises an outer ring, an inner ring, and an instrument mount. The outer ring is rotatably connected to the inner wall of the upper float 310 via a first horizontal axis, allowing it to rotate freely around the first horizontal axis. The inner ring is rotatably connected to the outer ring via a second horizontal axis, which is orthogonal to the first horizontal axis. The instrument mount is fixed at the center of the inner ring and is used to mount the measuring instrument. A gyroscope is a device that uses the angular momentum of a high-speed rotating body to sense the angular velocity of its housing relative to inertial space around one or two axes orthogonal to its rotation axis. This scheme, which mounts the measuring instrument inside the gyroscope and utilizes its automatic stabilization function to resist the effects of ocean currents, is existing technology and will not be elaborated further here.

[0029] When the buoyancy body pitches or rolls under the influence of ocean currents, the outer and inner rings rotate sequentially, ensuring that the instrument rack and the mounted measuring instruments remain vertical under the influence of gravity. This design achieves passive attitude decoupling between the pitch and roll degrees of freedom, ensuring that the measuring instruments always point in the predetermined direction and are not affected by the tilting of the buoyancy body.

[0030] A counterweight can be added to the bottom of the instrument mount to lower the center of gravity of the suspension system and enhance the gravity recovery effect. Low-friction bearings, such as ceramic ball bearings or self-lubricating bearings, can be installed at each rotating axis of the gyroscope to reduce the impact of frictional torque on attitude decoupling accuracy.

[0031] Specifically, the elastomer 440 is made of titanium-nickel alloy, and its elastic modulus and geometric dimensions are designed according to the working water depth and cable tension of the underwater glider system; the cylinder 410 is fixedly sleeved on the top of the cylindrical channel structure, a pair of pistons 430 are sealed and slidably sleeved with the cylinder 410, and a pair of sleeves 420 are sealed and slidably sleeved with the cylinder caps at the upper and lower ends of the cylinder 410.

[0032] The upper end of the anchor cable 200 is fixedly sleeved inside the lower sleeve 420. The upper sleeve 420 is coaxially connected to the bearing 210 via a limiting head 220, and the bearing 210 is fixedly sleeved in the central groove at the bottom of the upper float 310. The anchor cable 200 is made of steel wire rope, and the limiting head 220 is another steel wire rope with its upper end upset to form a limiting structure. The anchor cable 200 can then rotate freely relative to the buoyancy body 300 around the vertical axis of the device to release the cable torque.

[0033] The cylinder 410 is filled with high-viscosity silicone oil, and the piston 430 has several throttling holes 431 on its end face for oil passage. When the seawater causes the buoyancy body 300 to sway, the piston 430 is pulled by the anchor cable 200 and reciprocates in the cylinder 410. The silicone oil flows through the several throttling holes 431 and generates viscous resistance, which converts the kinetic energy of the swaying motion into heat energy and achieves rapid vibration damping.

[0034] Furthermore, the heave damping device 400 constitutes a spring-damping system, whose natural frequency is much lower than the wave frequency, forming a "low-pass filtering effect" on the rapid undulating pull of the surface buoy, thus attenuating the force amplitude transmitted to the underwater buoy; the damping coefficient of the hydraulic damping component is set to 0.7 to 1.0 times the critical damping to resist the dynamics of seawater flow.

[0035] Specifically, a multi-dimensional damping mechanism 500 is provided on the outer periphery of the bottom of the lower float 320. The multi-dimensional damping mechanism 500 consists of several sets of porous damping discs that flip longitudinally and laterally, which are used to increase fluid damping in the pitch and roll directions.

[0036] The multidimensional damping mechanism 500 includes a mounting component 530 adapted to be snapped onto the bottom of the lower float 320, a plurality of pitch damping plates 510 hinged to the upper port of the mounting component 530, and a plurality of roll damping plates 520 hinged to the arcuate sidewall of the mounting component 530; a connecting rod is provided on the central axis of the mounting component 530 and the connecting rod is inserted into the cylindrical channel structure of the lower float 320 and fixedly connected to the cylinder 410; a plurality of transverse hinge sleeves 531 are fixedly provided in an annular pattern at equal intervals at the edge of the upper port of the mounting component 530 for hinged to the pitch damping plates 510; a plurality of pairs of longitudinal hinge sleeves 532 are fixedly provided on the longitudinal line of the arcuate sidewall of the mounting component 530 for hinged to the roll damping plates 520.

[0037] When the buoyancy body 300 undergoes pitching or rolling motion, the porous damping disc cuts through the water. As the fluid flows through the through-holes, viscous resistance is generated, increasing fluid damping in the pitching and rolling directions and causing the oscillations to decay rapidly. The through-hole design significantly increases the resistance of the porous damping disc during high-speed oscillations, providing high damping.

[0038] The multi-degree-of-freedom passive vibration reduction and attitude stabilization device for deep-sea moorings of the present invention constructs the buoyancy body 300 into a symmetrical double-sphere structure, and sets the anchor cable 200 mooring point at the geometric center of the waist of the buoyancy body 300. This allows the fluid resistance generated by the upper and lower spheres in the ocean current to generate opposing moments around the mooring point, which cancel each other out, thereby eliminating most of the capsizing moment. Simultaneously, the center of gravity is positioned below the mooring point, utilizing gravity and the tension of the anchor cable 200 to achieve passive vertical stability. Based on this, more than 500 passive vibration reduction modules, including a gyroscope, an elastic-damped composite heave damping device 400, and a multi-dimensional damping mechanism 500, are integrated to suppress vibrations in the pitch / roll, yaw, and heave degrees of freedom, forming a complete multi-degree-of-freedom passive attitude stabilization and vibration reduction system.

[0039] It should be noted that in the actual deployment of the deep-sea mooring system, multiple attitude stabilization devices can be connected in series at different depths along the anchor cable 200mm, forming a multi-node observation network, depending on the needs of the observation mission. Each device operates independently and does not interfere with the others.

[0040] The terms "fixed connection" and "fixed installation" in this invention should be interpreted broadly, and can be achieved using conventional fixing methods such as bolting, welding, bonding, or integral molding, which are compatible with each other. The specific connection relationship between the components is based on the ability to achieve the function of this invention. The above are existing technologies and will not be elaborated further. The above embodiments are only for illustrating the technical concept and features of this invention, and are intended to enable those skilled in the art to understand the content of this invention and implement it accordingly. They should not be used to limit the scope of protection of this invention. All equivalent changes or modifications made according to the spirit and essence of this invention should be covered within the scope of protection of this invention.

Claims

1. A multi-degree-of-freedom passive vibration reduction and attitude stabilization device for deep-sea moorings, characterized in that: It includes a buoyancy body set above the anchor and anchor cable, the buoyancy body having a symmetrical double sphere structure and a waist-shaped constriction structure set between the two spheres; A heave damping device is disposed inside the waist-shaped necking structure for connecting to the upper end of the anchor cable, and the overall center of gravity of the device is vertically positioned below the waist-shaped necking structure; the heave damping device includes an elastic body for bearing the static load tension of the anchor cable and providing buffer stiffness. A hydraulic damping component, comprising a cylinder filled with a high-viscosity damping fluid and a pair of pistons and sleeves coaxially and fixedly connected to an elastomer, is used to convert the kinetic energy of the overall heave motion into heat energy through viscous damping motion. Under the action of horizontal ocean currents, the spheres above and below the buoyancy body deflect around its overall center of gravity. Under the obstruction of the anchor cable on the lower sphere, the upper and lower spheres generate torques in opposite directions around the waist-shaped constriction structure to passively counteract the overturning torque.

2. The multi-degree-of-freedom passive vibration reduction and attitude stabilization device for deep-sea moorings according to claim 1, characterized in that: The waist-shaped constricted structure is integrally formed and connected to the top of the lower float. The buoyancy body is composed of an upper float and a waist-shaped constricted structure that are detachably and fixedly connected. A counterweight is installed on the inner wall of the bottom of the lower float to increase the vertical floating stability of the buoyancy body.

3. The multi-degree-of-freedom passive vibration reduction and attitude stabilization device for deep-sea moorings according to claim 2, characterized in that: The upper and lower floats are both divided into upper and lower hemispherical shells and are fixedly connected to form a sphere. The central axis of the lower float has a cylindrical channel structure, and the channel hole passes through the upper and lower ends of the central axis of the lower float.

4. The multi-degree-of-freedom passive vibration reduction and attitude stabilization device for deep-sea moorings according to claim 3, characterized in that: The waist-shaped constricted structure is integrally formed and connected to the top of the lower float, and is detachably and fixedly connected to the bottom of the upper float.

5. The multi-degree-of-freedom passive vibration reduction and attitude stabilization device for deep-sea moorings according to claim 4, characterized in that: The elastomer is made of titanium-nickel alloy. The cylinder is fixedly sleeved on the top of the cylindrical channel structure. A pair of pistons are sealed and slidably sleeved with the cylinder. A pair of sleeves are sealed and slidably sleeved with the cylinder caps at the upper and lower ends of the cylinder.

6. The multi-degree-of-freedom passive vibration reduction and attitude stabilization device for deep-sea moorings according to claim 5, characterized in that: The upper end of the anchor cable is fixedly sleeved inside the lower sleeve, and a bearing is coaxially connected above the upper sleeve via a limiting head, with the bearing fixedly sleeved in the central groove at the bottom of the upper buoy; then the anchor cable can rotate freely relative to the buoyancy body around the vertical axis of the device to release the cable torque.

7. The multi-degree-of-freedom passive vibration reduction and attitude stabilization device for deep-sea moorings according to claim 6, characterized in that: The damping coefficient of the hydraulic damping component is set to 0.7 to 1.0 times the critical damping.

8. The multi-degree-of-freedom passive vibration reduction and attitude stabilization device for deep-sea moorings according to claim 7, characterized in that: The bottom outer periphery of the lower float is provided with a multi-dimensional damping mechanism, which consists of several sets of porous damping discs that flip longitudinally and laterally to increase fluid damping in the pitch and roll directions.

9. The multi-degree-of-freedom passive vibration reduction and attitude stabilization device for deep-sea moorings according to claim 8, characterized in that: The multidimensional damping mechanism includes a mounting component adapted to be snapped onto the bottom of the lower float, a plurality of pitch damping plates hinged to the upper port of the mounting component, and a plurality of roll damping plates hinged to the arcuate sidewall of the mounting component.

10. The multi-degree-of-freedom passive vibration reduction and attitude stabilization device for deep-sea moorings according to claim 9, characterized in that: Both the upper and lower buoys are integrally formed from pressure-resistant composite materials and filled with low-density buoyancy material.

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