A zero-buoyancy umbilical cable structure and its design method

Abstract

This invention discloses a zero-buoyancy umbilical cable structure and its design method. The structure includes components such as a zero-buoyancy cable, a high-pressure water pipe, and a buoyancy ball device. The cable and high-pressure water pipe are respectively fixed to the buoyancy ball device, which balances the weight of the high-pressure water pipe and the zero-buoyancy cable, achieving a balance between the total weight and total buoyancy of the zero-buoyancy umbilical cable structure. The zero-buoyancy cable mainly includes a coaxial cable for a simulated camera, a communication cable for communication between underwater and surface equipment, and a power supply cable for the underwater equipment. The buoyancy ball device mainly consists of an elliptical buoyancy ball and clips. Grooves on both sides of the elliptical buoyancy ball's long axis accommodate the high-pressure water pipe and the zero-buoyancy cable, and clips at both ends of the long axis provide fixation. Through holes on the long and short axes of the buoyancy ball allow rolled strips to pass through and fix the high-pressure water pipe and the cable respectively. This invention avoids cable dragging and water flow dragging, reduces power consumption, and improves equipment stability.

Description

Technical Field

[0001] This invention relates to the technical field of cage cleaning equipment, and in particular to a zero-buoyancy umbilical cable structure and its design method. Background Technology

[0002] In underwater operations of mesh cleaning robots, where power and high-pressure water are supplied, the dragging of the underwater robot's cable and the dragging caused by the water flow consume more power, and the additional buoyancy or gravity interferes with the equipment's posture, causing instability. Summary of the Invention

[0003] This invention provides a zero-buoyancy umbilical cable structure and its design method for a mesh cleaning robot, achieving the zero-buoyancy requirement of the underwater robot's umbilical cable.

[0004] In a first aspect, the present invention provides a zero-buoyancy umbilical cable structure, comprising: a cable, a high-pressure water pipe, and a buoyancy ball device, wherein the cable and the high-pressure water pipe are respectively fixed on the buoyancy ball device, and the buoyancy ball device balances the weight of the high-pressure water pipe and the cable, so that the total gravity and total buoyancy of the zero-buoyancy umbilical cable structure are balanced.

[0005] Secondly, the present invention provides a design method for a zero-buoyancy umbilical cable structure, which includes the following steps:

[0006] Given the length L of the high-pressure water pipe, calculate the weight of the high-pressure water pipe itself and the weight of the high-pressure water flow inside it to obtain the total weight of the high-pressure water pipe. Calculate the buoyancy of the high-pressure water pipe based on the density of seawater. ;

[0007] Given the length L of the cable, calculate the total weight of the cable. Calculate the total buoyancy of the cable based on the density of seawater. ;

[0008] Configure buoyancy balls based on the total weight of the high-pressure water pipes. Total weight of the cable And the gravity of the buoyancy ball The sum equals the buoyancy of the high-pressure water pipe buoyancy of cables buoyancy of a buoyant ball The sum of these values ​​is used to calculate the difference between the equilibrium gravity and buoyancy of the buoyancy ball device;

[0009] Design the structure of the buoyancy ball device based on the difference between the buoyancy force and the balance force of the buoyancy ball device;

[0010] The buoyancy ball device is structurally snapped into and fixed to the high-pressure water pipe and cable, completing the zero-buoyancy umbilical cable structure of the mesh cleaning robot. Beneficial effects

[0011] 1) The zero-buoyancy umbilical cable structure of this invention includes components such as a zero-buoyancy cable, a high-pressure water pipe, and a buoyancy ball device, all of which are arranged in a specific manner. The zero-buoyancy cable mainly includes a coaxial cable for the analog camera, a communication cable for communication between underwater and surface equipment, and a power supply cable for the underwater equipment. The buoyancy ball device mainly consists of an elliptical buoyancy ball and clips, primarily used to fix the high-pressure water pipe and the zero-buoyancy cable, while balancing their weight to achieve a balance between total gravity and total buoyancy, thus fulfilling the requirement of zero buoyancy. This reduces cable drag, water flow drag, power consumption, and improves equipment stability.

[0012] 2) The present invention has the characteristics of simple structure, flexible deployment and low cost.

[0013] 3) The cable of this invention employs two twisted-pair power lines arranged symmetrically. This design increases the load-bearing capacity of the power lines while reducing signal interference from the power supply to the coaxial cable and the four-core shielded mesh cable. The coaxial cable is mainly used for transmitting video signals and other information from underwater analog cameras, and it is arranged side-by-side between the twisted-pair power lines. The four-core shielded mesh cable is mainly used for data communication and command transmission of underwater electronic equipment. The space between the two twisted-pair power lines is filled with 10 strands of imported 3000D Kevlar material, increasing the overall tensile strength of the cable to 300kg. The cable bundle is sheathed with foamed polyurethane to improve the cable's buoyancy.

[0014] 4) The buoyancy ball device of this invention has cable-holding grooves on both the upper and lower sides of the long axis of the ellipsoidal buoyancy ball. Cables and high-pressure water pipes extending from the same side of the cable-holding grooves are secured using clips. Through holes are formed on the short axis of the ellipsoidal buoyancy ball, through which a strip passes to secure the upper and lower cables and high-pressure water pipes respectively. The straight cable-holding grooves accommodate the high-pressure water pipes, reducing pressure loss. The arcuate cable-holding grooves are calculated based on the minimum bending radius of the zero-buoyancy cable, improving cable stability and reducing cable bending losses. Attached Figure Description

[0015] Figure 1 This is a front view of a zero-buoyancy umbilical cable structure for a mesh cleaning robot provided in Embodiment 1 of the present invention;

[0016] Figure 2 This is a perspective view of a zero-buoyancy umbilical cable structure for a mesh cleaning robot provided in Embodiment 1 of the present invention;

[0017] Figure 3 This is a schematic diagram illustrating the gravity and buoyancy force analysis of a zero-buoyancy umbilical cable structure for a mesh cleaning robot provided in Embodiment 1 of the present invention;

[0018] Figure 4This is a schematic diagram of the internal structure of the cable provided by the present invention;

[0019] Figure 5 This is a schematic diagram of the structure of the buoyancy ball provided by the present invention;

[0020] Figure 6 This is a top view of the buoyancy ball provided by the present invention;

[0021] Figure 7 This invention provides Figure 6 Schematic diagram of the cross section at point AA;

[0022] Figure 8 This is a right view of the buoyancy ball provided by the present invention;

[0023] Figure 9 This is a flowchart illustrating the zero-buoyancy umbilical cable structure design method for a mesh cleaning robot provided by the present invention. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0025] See Figure 1 This is a schematic diagram of a zero-buoyancy umbilical cable structure for a mesh cleaning robot according to Embodiment 1 of the present invention. The zero-buoyancy umbilical cable structure includes a zero-buoyancy cable 10, a high-pressure water pipe 20, and a buoyancy ball device 30. The zero-buoyancy cable 10 and the high-pressure water pipe 20 are respectively fixed to the buoyancy ball device 30. The buoyancy ball device 30 balances the weight of the high-pressure water pipe 20 and the zero-buoyancy cable 10, so that the total weight and total buoyancy of the zero-buoyancy umbilical cable structure are balanced. One end of the cable 10 of the zero-buoyancy umbilical cable structure is connected to the surface control equipment, and the high-pressure water pipe 20 is connected to a high-pressure water source. The other end of the cable 10 is connected to the underwater mesh cleaning robot, and the high-pressure water pipe 20 is connected to a high-pressure water gun.

[0026] The zero-buoyancy umbilical cable primarily provides buoyancy through the zero-buoyancy cable 10, the buoyancy ball 31, and the high-pressure water pipe 20. Its main weight is provided by the high-pressure water pipe 20 and the zero-buoyancy cable 10. Figure 3 As shown.

[0027] Assume the length of the high-pressure water pipe 20 is L, and the density of the high-pressure water pipe 20 is... , radius is The inner diameter is .

[0028] Cable density 10 , radius is The stress analysis of the high-pressure water pipe 20 is as follows:

[0029] (1)

[0030] (2)

[0031] in It is the acceleration due to gravity. For the weight of the high-pressure water pipe 20, For the buoyancy of the high-pressure water pipe 20, This is the density of seawater.

[0032] The stress analysis of cable 10 is as follows:

[0033] (3)

[0034] (4)

[0035] Where is the acceleration due to gravity. , The weight of cable 10, For the buoyancy of cable 10, Let be the density of seawater. The force analysis of buoyancy ball 31 is as follows:

[0036] (5)

[0037] (6)

[0038] in The volume of water displaced Let the mass of buoyancy ball 31 be... For the buoyancy of buoyancy ball 31, The weight of buoyancy ball 31 Let be the density of seawater. According to formulas (1) to (6), the zero buoyancy requirement is met when the following conditions are met during installation.

[0039] (7)

[0040] The zero-buoyancy cable 10 includes two twisted-pair power lines 11, a four-core shielded mesh cable 12, two coaxial cables 13, and tensile filler 14. The two twisted-pair power lines 11 are symmetrically arranged on the left and right sides, and the four-core shielded mesh cable 12 is symmetrically arranged with the two coaxial cables 13 on the same side. The tensile filler 14 is in the middle. The two twisted-pair power lines 11, the four-core shielded mesh cable 12, the two coaxial cables 13, and the tensile filler 14 are wrapped with non-woven fabric 15 to form a complete cable bundle. The cable is surrounded by foamed polyurethane 16 to form a sheath, and the sheath is wrapped with waterproof polyurethane 17.

[0041] The two twisted-pair power cables 11 are mainly used to carry high-voltage power. Their conductor cross-sectional area is 1.5mm², the conductor structure is 84 / 0.15 (84 copper wires, each copper wire is 0.15mm), the twisted outer diameter is 1.6mm, the insulation material is PE material, the insulation thickness is 0.5mm, the insulation outer diameter is 2.6mm, and they are twisted in red / black and white / blue pairs respectively. To improve the flexibility of the zero-buoyancy cable 10, two twisted-pair power lines 11 are arranged symmetrically. This design increases the load-bearing capacity of the power lines while reducing signal interference from the power supply to the coaxial cable 13 and the four-core shielded mesh cable 12. The coaxial cable 13 consists of two coaxial signal lines with a conductor cross-sectional area of ​​2 mm², a characteristic impedance of 75 Ω, a conductor structure of 7 / 0.15 (7 wires with a diameter of 0.15 mm twisted together), a twisted outer diameter of 0.45 mm, and PE insulation material with an insulation thickness of 0.5 mm and an insulation outer diameter of 1.5 mm. Its overall structure mainly consists of bare copper wire (8 / 0.1, composed of 8 fine bare copper wires with a diameter of 0.1 mm twisted together) + 80% braiding density (referring to the coverage density of the cable's metal braided shielding layer (usually tinned copper wire or bare copper wire) of 80%) + PE transparent sheath. The final diameter of this cable after adding the sheath is between 2.95 mm and 3.0 mm. Primarily used for transmitting video signals and other information from underwater simulation cameras, it is arranged in a side-by-side configuration and distributed between twisted-pair power cables 11, such as... Figure 4 As shown; the four-core shielded cable 12 is mainly composed of four copper wires, each with a conductor cross-sectional area of ​​0.2 mm², a conductor structure of 7 / 0.2, a twisted outer diameter of 0.6 mm, and PE insulation material with an insulation thickness of 0.2 mm and an insulation outer diameter of 1.0 mm. It consists of aluminum foil + 80% tin-plated wire braiding density + PE sheath, with the sheath outer diameter being 4.1-4.3 mm. It is mainly used for data communication and command transmission of underwater electronic equipment. Secondly, to improve the overall tensile strength of the cable to 300 kg, the two twisted power wires 11 are filled with 10 strands of imported 3000D Kevlar material. Finally, to improve the cable's buoyancy, the outer sheath of the wire bundle is formed by foamed polyurethane 16, with a sheath thickness of 9 mm and a yellow color. The outer sheath is wrapped with waterproof polyurethane 17, with a thickness of 1 mm. The final product, the zero-buoyancy cable 10, has an outer diameter of 30 mm.

[0042] The buoyancy ball device 30 includes a buoyancy ball 31 and a buckle 32. The buoyancy ball is ellipsoidal in shape, with cable-holding grooves on both sides of its major axis. One groove is a straight groove 311 for accommodating the high-pressure water pipe 20, and the other is an arc-shaped groove 312 for accommodating the zero-buoyancy cable 10. The high-pressure water pipe 20 and the zero-buoyancy cable 10 are fixed on the same side by buckles 32 at both ends of the major axis of the buoyancy ball. A through hole 310 is provided on the minor axis of the ellipsoidal buoyancy ball for flexible connectors such as cable ties to pass through and fix the high-pressure water pipe 20 and the zero-buoyancy cable 10 respectively.

[0043] The width of the cable clamping groove can be adjusted according to the outer diameter of the cable 10 and the high-pressure water pipe 20. Preferably, the buoyancy ball 31 has a 5mm through hole 310 in the middle, mainly used for fixing the high-pressure water pipe 20 and the zero-buoyancy cable 10 after cable ties or similar items pass through. To prevent the high-pressure water pipe 20 from bending during the binding process, which would lead to pressure loss, the cable clamping groove 311 accommodating the high-pressure water pipe 20 is straight. The cable clamping groove 312 accommodating the zero-buoyancy cable 10 is arc-shaped, and the arc is calculated based on the minimum bending radius of the zero-buoyancy cable 10.

[0044] Since the sum of the weights of the zero-buoyancy cable 10 and the high-pressure water pipe 20 must be greater than the sum of the buoyancy of the cable and the buoyancy of the high-pressure water pipe, it can be seen from formula (7) that the buoyancy ball device 30 balances the difference between the weight and the buoyancy, thereby achieving the desired zero-buoyancy state when the weights of the cable 10 and the high-pressure water pipe 20 are balanced with the buoyancy of the high-pressure water pipe and the cable 10.

[0045] See Figure 9 This is a flowchart illustrating the zero-buoyancy umbilical cable structure design method for a mesh cleaning robot provided by the present invention.

[0046] S1: Set the length L of the high-pressure water pipe 20, calculate the weight of the high-pressure water pipe 20 itself and the weight of the high-pressure water flow inside it; combine with Seawater density, calculate the buoyancy of the high-pressure water pipe. .

[0047] In this step, the length of the underwater high-pressure water pipe is L, and the density of the high-pressure water pipe 20 is... , radius is The inner diameter is The cable density is 10. , radius is The stress analysis of the high-pressure water pipe 20 is as follows:

[0048] (1)

[0049] (2)

[0050] in It is the acceleration due to gravity. For the weight of the high-pressure water pipe 20, For the buoyancy of the high-pressure water pipe 20, This represents the density of the high-pressure water flow.

[0051] S2: Length L of cable 10, calculate the total weight of cable 10. ; Calculate the total buoyancy of cable 10 based on seawater density. .

[0052] In this step, since the high-pressure water pipe 20 and cable 10 for the underwater net robot are fixed together, both have a length of L during underwater operation. The stress analysis of cable 10 is as follows:

[0053] (3)

[0054] (4)

[0055] in It is the acceleration due to gravity. The weight of cable 10, The buoyancy of cable 10.

[0056] S3: Configure buoyancy ball 31, based on the total weight of high-pressure water pipe 20. Total weight of cable 10 The total weight of buoyancy ball 31 The sum equals the buoyancy of the high-pressure water pipe 20. buoyancy of cable 10 buoyancy of buoyancy ball 31 Calculate the difference F between the equilibrium gravity and buoyancy of the buoyancy ball device.

[0057] In this step, the force analysis of the buoyancy ball 31 is as follows:

[0058] (5)

[0059] (6)

[0060] in The volume of water displaced by the buoyant sphere is 31. Let the mass of buoyancy ball 31 be... For the buoyancy of buoyancy ball 31, The weight of buoyancy ball 31.

[0061] According to formulas (1) to (6), the zero buoyancy requirement is met when the following conditions are met for the installation layout.

[0062] (7)

[0063] S4: Design the structure of the buoyancy ball device based on the difference F between the buoyancy force and the buoyancy force of the buoyancy ball device.

[0064] In this step, because the sum of the weights of cable 10 and high-pressure water pipe 20 is greater than the sum of the buoyancy of cable 10 and high-pressure water pipe 20, the density of the buoyancy ball 31 is designed to be relatively small; conversely, because the sum of the weights of cable 10 and high-pressure water pipe 20 is less than the sum of the buoyancy of cable 10 and high-pressure water pipe 20, the density of the buoyancy ball is designed to be relatively large. Based on the difference... Design the structure of the buoyancy ball device and obtain the volume of the buoyancy ball 31. The density of the buoyancy ball is determined to achieve the desired zero buoyancy state when the weight of the cable and the weight of the high-pressure water pipe are balanced with the buoyancy of the high-pressure water pipe and the cable.

[0065] The weight of the buckle 32 of the buoyancy ball device 30 is negligible.

[0066] S5: The structure of the buoyancy ball device 30 is snapped into and fixed to the high-pressure water pipe 20 and the cable 10, completing the zero-buoyancy umbilical cable structure of the net cleaning robot.

[0067] In this step, specifically, the buoyancy ball 31 of the buoyancy ball device 30 is ellipsoidal in shape. The ellipsoidal buoyancy ball has cable-holding grooves on both the upper and lower sides of its major axis. One groove is a straight groove 311, used to accommodate the high-pressure water pipe 20 and prevent it from bending during binding. The other groove is an arc-shaped groove 312, used to accommodate the zero-buoyancy cable 10, calculated based on the minimum bending radius of the zero-buoyancy cable 10. A through hole 310 is provided on the minor axis of the ellipsoidal buoyancy ball 31, allowing flexible connectors such as cable ties to pass through and secure the high-pressure water pipe 20 and the zero-buoyancy cable 10 respectively.

[0068] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A zero-buoyancy umbilical cable structure, characterized in that, It includes a cable, a high-pressure water pipe, and a buoyancy ball device. The cable and the high-pressure water pipe are respectively fixed on the buoyancy ball device. The buoyancy ball device balances the weight of the high-pressure water pipe and the cable, so that the total weight and total buoyancy of the zero-buoyancy umbilical cable structure are balanced. The buoyancy ball device includes a buoyancy ball and a buckle, and the cable and high-pressure water pipe are fixed to the buoyancy ball by the buckle; The buoyancy ball is ellipsoidal in shape. The long axis of the ellipsoidal buoyancy ball has cable-holding grooves on both the top and bottom. One groove is a straight groove for accommodating the high-pressure water pipe, and the other is an arc-shaped groove for accommodating the cable. The high-pressure water pipe and the cable on the same side are fixed by buckles at both ends of the long axis of the buoyancy ball. The short axis of the ellipsoidal buoyancy ball is provided with through holes for flexible connectors to pass through and fix the high-pressure water pipe and the cable respectively.

2. The zero-buoyancy umbilical cable structure as described in claim 1, characterized in that, The weight of the high-pressure water pipe The weight of the cable The gravity of a buoyant sphere The sum of these equals the buoyancy of the high-pressure water pipe. buoyancy of cables buoyancy of a buoyant ball sum.

3. The zero-buoyancy umbilical cable structure as described in claim 1, characterized in that, The length of the high-pressure water pipe is L, and the density of the high-pressure water pipe is... , radius is The inner diameter is The forces acting on the high-pressure water pipe are as follows: （1） （2） in It is the acceleration due to gravity. The weight of the high-pressure water pipe, The buoyancy of the high-pressure water pipe, The density of the working liquid environment for a zero-buoyancy umbilical cable structure.

4. The zero-buoyancy umbilical cable structure as described in claim 1, characterized in that, The cable linear density is: The cable is of length L and radius is The forces acting on the cable are as follows: （3） （4） in It is the acceleration due to gravity. For the weight of the cable, For the buoyancy of the cable, The density of the working liquid environment for a zero-buoyancy umbilical cable structure.

5. The zero-buoyancy umbilical cable structure as described in claim 1, characterized in that, The forces acting on the buoyancy ball device are as follows: （5） （6） in The volume of water displaced For the mass of the buoyant sphere, The buoyancy of the buoyant ball, The weight of the buoyant sphere. The density of the working liquid environment for a zero-buoyancy umbilical cable structure. This is the acceleration due to gravity.

6. The zero-buoyancy umbilical cable structure as described in claim 1, characterized in that, The cable includes two twisted-pair power lines, a four-core shielded mesh cable, two coaxial cables, and tensile filler. The two twisted-pair power lines are symmetrically arranged on the left and right sides, and the four-core shielded mesh cable is symmetrically arranged with the two coaxial cables on the same side. The tensile filler is in the middle. The two twisted-pair power lines, the four-core shielded mesh cable, the two coaxial cables, and the tensile filler are wrapped with non-woven fabric to form a complete cable bundle. The cable is surrounded by foamed polyurethane to form a sheath, and the sheath is wrapped with waterproof polyurethane.

7. The zero-buoyancy umbilical cable structure as described in claim 6, characterized in that, The twisted-pair power cable has a conductor cross-sectional area of ​​1.5 mm², a conductor structure of 84 copper wires, each copper wire being 0.15 mm long, a twisted outer diameter of 1.6 mm, and PE insulation material with an insulation thickness of 0.5 mm and an insulation outer diameter of 2.6 mm. The coaxial conductor has a cross-sectional area of ​​2 mm², a characteristic impedance of 75 Ω, and a conductor structure consisting of 7 stranded wires with a diameter of 0.15 mm and a stranded outer diameter of 0.45 mm. The insulation material is PE material with an insulation thickness of 0.5 mm and an insulation outer diameter of 1.5 mm. The four-core shielded network cable is mainly composed of four copper wires. The conductor cross-sectional area of ​​the copper wire is 0.2mm², the conductor structure is 7 / 0.2, the outer diameter of the strand is 0.6mm, the insulation material is PE material, the insulation thickness is 0.2mm, and the insulation outer diameter is 1.0mm. The shielding layer of the four-core shielded network cable is composed of aluminum foil, 80% tin-plated wire braiding density, and PE sheath, with the outer diameter of the sheath being 4.1-4.3mm. The tensile filler is 10 strands of 3000D Kevlar material.

8. A design method for a zero-buoyancy umbilical cable structure as described in any one of claims 1-7, characterized in that, Its features are, Given the length L of the high-pressure water pipe, calculate the weight of the high-pressure water pipe itself and the weight of the high-pressure water flow inside it to obtain the total weight of the high-pressure water pipe. Calculate the buoyancy of the high-pressure water pipe based on the density of seawater. ; Given the length L of the cable, calculate the total weight of the cable. Calculate the total buoyancy of the cable based on the density of seawater. ; Configure buoyancy balls based on the total weight of the high-pressure water pipes. Total weight of the cable And the gravity of the buoyancy ball The sum equals the buoyancy of the high-pressure water pipe buoyancy of cables buoyancy of a buoyant ball The sum of these values ​​is used to calculate the difference between the equilibrium gravity and buoyancy of the buoyancy ball device; Design the structure of the buoyancy ball device based on the difference between the buoyancy force and the balance force of the buoyancy ball device; The buoyancy ball device is structurally snapped into and fixed to the high-pressure water pipe and cable, completing the zero-buoyancy umbilical cable structure of the mesh cleaning robot.

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