CONTROL METHOD FOR SHIP MOORING STABILITY AUXILIARY STRUCTURE

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The application claims priority to Chinese patent application No. 202411911071.7, filed on Dec. 24, 2024, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to the technical field of ship mooring, and in particular to a control method for a ship mooring stability auxiliary structure.

BACKGROUND

Ships are connected to a dock via mooring equipment such as mooring cables, bollards, and winches, which ensures their stability while berthing at the dock and facilitates the loading and unloading of cargo and the boarding and disembarking of personnel. When a ship mooring area encounters severe conditions such as strong winds, swells, and long-period waves, the ship motion is significant. Relying solely on the restraint of the mooring lines is insufficient to guarantee the ship stability during loading and unloading operations, and can easily lead to excessive stress on the mooring lines, resulting in a breakage accident.

Harbor tugboats are tugboats that perform towing operations within the port area. They are mainly used to assist large ships in entering and leaving the port, entering and leaving the dock, berthing and leaving the wharf, turning around, moving berths, and towing barges. In harsh environmental conditions, the harbor tugboats are generally used to push the moored ship on the seaward side to suppress its motion. This method of assisting mooring stability plays a positive role in ensuring the stability and safety of moored ships under harsh environmental conditions. Existing harbor tugboats still have many shortcomings in assisting ship mooring methods:

• • (1) A point of action between the harbor tugboat and the moored ship is fixed near a waterline. This position cannot be adjusted, so it is impossible to optimize the mooring stability of the moored ship.
  • (2) The harbor tugboats rely on rubber products such as fenders for collision protection and buffering between themselves and the moored ship. However, there is a lot of friction between the rubber products and the ship, and they are easily damaged and fail during operation, which in turn leads to direct collision between the harbor tugboats and the moored ship.
  • (3) After working for a period of time, the harbor tugboat needs to return to a workboat dock for energy replenishment. This may lead to the interruption of the mooring assistance operation, which in turn affects the mooring stability of the moored ship.

Therefore, in order to address the problems existing in the operation of the tugboats in ensuring the mooring stability of moored ships, it is of great practical significance to design a device and method for assisting mooring that can adjust the operating position, maintain a good connection with the moored ship during operation, and recover energy during work.

SUMMARY

The objective of the present disclosure is to overcome the shortcomings of the prior art and provide a control method for a ship mooring stability auxiliary structure.

The objective of the present disclosure can be achieved through the following technical solutions:

A control method for a ship mooring stability auxiliary structure, the ship mooring stability auxiliary structure including a tugboat, a mechanical arm, and a magnetic chuck connected in sequence, the mechanical arm including a plurality of arm segments hinged in sequence, and a telescopic drive component being disposed between the two adjacent arm segments, wherein the control method includes the following specific steps:

• • S10: obtaining design breaking force of a ship mooring cable and ship dimensions;
  • S20: setting tugboat auxiliary thrust, an auxiliary quantity, and an auxiliary connection position of the magnetic chuck to a ship;
  • S30: starting the auxiliary thrust and the tugboat of the auxiliary quantity, and connecting the magnetic chuck to the ship according to the auxiliary connection position;
  • S40: calculating post-assistance maximum tension of the mooring cable according to the ship dimensions, the auxiliary thrust, the auxiliary quantity, and the auxiliary connection position;
  • S50: determining whether the ship is safe to moor according to the design breaking force and the post-assistance maximum tension of the mooring cable; and
  • S60: if the ship is not safe to moor, adjusting the auxiliary thrust and the auxiliary connection position, and repeating steps S20 to S50 until it is determined that the ship is safe to moor.

In one of embodiments, between step S10 and step S20, the control method further includes the following steps:

• • step S11: obtaining pre-assistance maximum tension of the mooring cable when the ship is moored;
  • step S12: determining whether the ship is safe to moor according to the design breaking force and the pre-assistance maximum tension of the mooring cable; and
  • step S13: if the ship is safe to moor, determining that no stability auxiliary structure is needed; otherwise, determining that the stability auxiliary structure is needed, and performing steps S20 to S60.

In one of embodiments, step S12 includes the following steps:

• • when the pre-assistance maximum tension satisfies the following relationship: F₁≤βF_s, where F_s is the design breaking force of the mooring cable, F₁ is the pre-assistance maximum tension of the mooring cable, β is a safety factor satisfying 45%≤β≤75%.

In one of embodiments, before step S20, the control method further includes the following specific steps:

• • obtaining a tugboat model and obtaining the auxiliary thrust of the tugboat according to the tugboat model.

In one of embodiments, in step S20, the auxiliary connection position between the magnetic chuck and the ship includes a horizontal distance and a vertical distance between a center point of the magnetic chuck and a center of gravity of the ship, as well as a distance between center points of the two adjacent tugboats.

In one of embodiments, in step S20, the ship dimensions include a ship modeled length and a ship modeled depth.

In one of embodiments, in step S40, when the tugboat quantity is 1, the post-assistance maximum tension of the mooring cable satisfies the following relationship:

F 2 = exp ⁢ ( 2.02 ) · ( 3.65 · y D - 0.06 · x L ) · f

• • where: F₂ is the post-assistance maximum tension of the mooring cable, x is the horizontal distance between the center point of the magnetic chuck and the center of gravity of the ship, y is the vertical distance between the center point of the magnetic chuck and the center of gravity of the ship, L is the ship modeled length, D is the ship modeled depth, and f is the auxiliary thrust of the tugboat.

In one of embodiments, in step S40, when the tugboat quantity is greater than 1, the post-assistance maximum tension of the mooring cable satisfies the following relationship:

F 2 = exp ⁡ ( 1 . 9 ⁢ 1 ) · { 3.65 · [ sum ( l n ) L ] - 1.13 · [ average ( x n ) L ] + 2.68 · [ average ( y n ) D ] } · f

F₂ is the post-assistance maximum tension of the mooring cable, x_n is the horizontal distance between the center point of the magnetic chuck of the n-th tugboat from left to right and the center of gravity of the ship, y_n is the horizontal distance between the center point of the magnetic chuck of the n-th tugboat from left to right and the center of gravity of the ship, l_n is the distance between the center points of the n-th tugboat and the adjacent tugboat on the right, L is the ship modeled length, D is the ship modeled depth, and f is the auxiliary thrust of the tugboat.

In one of embodiments, step S50 includes the following steps:

• • when the post-assistance maximum tension satisfies the following relationship: F₂≤βF_s, where F_s is the design breaking force of the mooring cable, F₂ is the post-assistance maximum tension of the mooring cable, β is a safety factor satisfying 45%≤β≤75%.

In one of embodiments, after step S30, the control method further includes the following steps:

• • obtaining a motion amplitude of the ship; and
  • controlling damping force of the telescopic drive component according to the motion amplitude of the ship.

Compared with the prior art, the present disclosure has the following advantages:

• • 1. The above-mentioned control method for the ship mooring stability auxiliary structure can obtain the post-assistance maximum tension of the mooring cable through the ship dimensions, auxiliary thrust, auxiliary quantity, and auxiliary connection position. By comparing the design breaking force of the mooring cable with the post-assistance maximum tension, whether the ship is safe to moor can be determined. By continuously adjusting the auxiliary thrust and auxiliary connection position, positive feedback of the ship mooring stability auxiliary structure can be achieved until the ship is safe to moor. This method is beneficial for adapting to different wind loads, wave loads, and water flow loads when the ship is moored.
  • 2. Before using the ship mooring stability auxiliary structure, the design breaking force of the mooring cable and the pre-assistance maximum tension can be used to determine whether the ship is safe to moor. If it is safe, the ship mooring stability auxiliary structure is not needed to assist in mooring, which helps to save auxiliary energy consumption. If it is not safe, then the auxiliary structure is started. The determination criteria are clear, which helps to control the ship mooring stability auxiliary structure.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic structural diagram of a ship mooring stability auxiliary structure and a tugboat in the present disclosure.

FIG. 2 is a schematic diagram of a connection structure between a ship mooring stability auxiliary structure and a tugboat and a ship in the present disclosure.

FIG. 3 is a schematic diagram of a first structure of a ship mooring stability auxiliary structure in the present disclosure.

FIG. 4 is a schematic diagram of a second structure of a ship mooring stability auxiliary structure in the present disclosure.

FIG. 5 is a schematic diagram of a connection structure between a mechanical arm and a magnetic chuck in the present disclosure.

FIG. 6 is a schematic structural diagram of a mechanical arm and a connecting bracket in the present disclosure.

FIG. 7 is a schematic structural diagram of a magnetic chuck in the present disclosure.

FIG. 8 is a schematic structural diagram of a telescopic drive component in the present disclosure.

FIG. 9 is a schematic structural diagram of a controller and an energy storage device in the present disclosure.

FIG. 10 is a flowchart of a control method for a ship mooring stability auxiliary structure in the present disclosure.

Description of reference signs: 100. Ship mooring stability auxiliary structure; 10. Magnetic chuck; 11. Magnetic block; 12. Corner magnetic block; 13. Central control board; 20. Mechanical arm; 21. Arm segment; 22. Telescopic drive component; 221. Permanent magnet; 222. Electromagnetic coil; 23. Protective cover; 231. Hard shell; 232. Protective cloth; 233. Telescopic corrugated pipe; 30. Connecting bracket; 31. First telescopic rod; 32. Second telescopic rod; 33. Transition component; 34. First folding rod; 35. Second folding rod; 36. L-shaped bracket; 40. Controller; 41. Energy storage device; 50. Tugboat; and 60. Ship.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present disclosure will now be described in detail with reference to the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present disclosure, and provides detailed implementations and specific operation processes. However, the scope of protection of the present disclosure is not limited to the following embodiment.

As shown in FIG. 1 to FIG. 5, in one embodiment, a ship mooring stability auxiliary structure 100 is provided, including a magnetic chuck 10 and a mechanical arm 20;

the magnetic chuck 10 includes a plurality of magnetic blocks 11, which are arranged in magnetic row groups along a first direction; the plurality of magnetic row groups are arranged in a second direction; in the first direction, the two adjacent magnetic blocks 11 are hinged to each other, and in the second direction, the two adjacent magnetic blocks 11 are hinged to each other;

further, one end of the mechanical arm 20 is connected to the magnetic chuck 10, and the other end of the mechanical arm 20 is used to connect to a tugboat 50; the mechanical arm 20 includes a plurality of arm segments 21 that are hinged in sequence; a telescopic drive component 22 is provided between the two adjacent arm segments 21 to change an included angle between the two adjacent arm segments 21.

The aforementioned ship mooring stability auxiliary structure 100 is equipped with the mechanical arm 20 that connects to the magnetic chuck 10 and the tugboat 50 respectively, and the magnetic chuck 10 is connected to a ship 60, thus realizing the connection between the tugboat 50 and the ship 60. Since the tugboat 50 is connected to the ship 60 by using the magnetic chuck 10, the tightness of the connection between the tugboat 50 and the ship 60 can be changed by adjusting the magnetic force of the magnetic chuck 10. The connection or disconnection between the tugboat 50 and the ship 60 can also be controlled by on/off control of the magnetic chuck 10. Further, the mechanical arm 20 includes the plurality of arm segments 21 that are hinged in sequence, and telescopic drive component 22 is provided between the arm segments 21. Therefore, the multiple telescopic drive components 22 can control the length and height of the mechanical arm 20 by extending and retracting different lengths, thereby controlling a connection position between the magnetic chuck 10 and the ship 60. The telescopic drive components 22 can also extend and retract with a amplitude of swaying when the ship 60 sways back and forth along the water. Meanwhile, the magnetic chuck 10 includes the multiple magnetic blocks 11, which are hinged to each other to form a flexible magnetic chuck 10 with a variable shape, which can adapt to a curved shell of the ship 60 and make the connection between the magnetic chuck 10 and the ship 60 more reliable. Therefore, the ship mooring stability auxiliary structure 100 can control the connection position between the magnetic chuck 10 and the ship 60 according to a mooring situation, and adjust the shape of the magnetic chuck 10 according to the curved shell of the ship 60, so as to facilitate the tugboat 50 to assist the ship 60 in mooring, which is conducive to improving the mooring stability of the ship 60.

Specifically, in one embodiment, the second direction is perpendicular to the first direction. In the first direction, the two adjacent magnetic blocks 11 are hinged to each other, so that they can rotate around the axis of the second direction. In the second direction, the two adjacent magnetic blocks 11 are hinged to each other, so that they can rotate around the axis in the first direction.

In this specific embodiment, the first direction is a horizontal direction and the second direction is a vertical direction. The two adjacent magnetic blocks 11 in the horizontal direction can rotate around the vertical axis, and two adjacent magnetic blocks 11 in the vertical direction can rotate around the horizontal axis.

Specifically, as shown in FIG. 5 and FIG. 6, in one embodiment, the ship mooring stability auxiliary structure 100 further includes a connecting bracket 30, which is hinged to one end of the mechanical arm 20. The magnetic block 11 located at the corner of the magnetic chuck 10 is a corner magnetic block 12, and the connecting bracket 30 is connected to the corner magnetic block 12 respectively.

The connecting bracket 30 has a first telescopic rod 31 and a second telescopic rod 32. The first telescopic rod 31 can extend and retract in the first direction, and the second telescopic rod 32 can extend and retract in the second direction.

The ship mooring stability auxiliary structure 100 has the connecting bracket 30 between the mechanical arm 20 and the magnetic chuck 10. The connecting bracket 30 is equipped with the first telescopic rod 31 and the second telescopic rod 32. The first telescopic rod 31 can extend and retract in the first direction and interact with the plurality of magnetic blocks 11 that are hinged to each other in the first direction, so that the magnetic blocks 11 hinged to each other in the first direction can rotate relative to each other, thereby changing the curvature of the magnetic chuck 10 in the first direction. At the same time, the second telescopic rod 32 can extend and retract in the second direction and interact with a plurality of magnetic blocks 11 that are hinged to each other in the second direction, so that the magnetic blocks 11 hinged to each other in the second direction can rotate relative to each other, thereby changing the curvature of the magnetic chuck 10 in the second direction, and thus changing the shape of a magnetic surface of the magnetic chuck 10. This structure is used to adapt to the curved shell of the ship 60 and improve the connection tightness of the magnetic chuck 10.

Further, as shown in FIG. 5, in one embodiment, a transition component 33 is provided between the connecting bracket 30 and the corner magnetic block 12. One end of the transition component 33 is ball-connected to the connecting bracket 30, and the other end of the transition component 33 is ball-connected to the corner magnetic block 12.

The transition component 33 is provided between the connecting bracket 30 and the corner magnetic block 12, realizing a double spherical connection. When the curvature of the magnetic chuck 10 in the first and second directions is changed, the connection angle between the transition component 33 and the corner magnetic block 12 can be changed, and the connection angle between the transition component 33 and the connecting bracket 30 can be changed. This is beneficial to improving the flexibility of the curvature change of the magnetic chuck 10 in the first and second directions, and can adapt to a large-angle curved surface of the ship 60 during mooring.

Further, as shown in FIG. 6, in one embodiment, the connecting bracket 30 further includes a first folding rod 34 and a second folding rod 35, one end of the first folding rod 34 being hinged to one end of the first telescopic rod 31, and one end of the second folding rod 35 being hinged to one end of the second telescopic rod 32.

The connecting bracket 30 has the first folding rod 34 hinged to one end of the first telescopic rod 31 and a second folding rod 35 hinged to one end of the second telescopic rod 32. Therefore, when the curvature of the magnetic chuck 10 in the first and second directions is changed, the first folding rod 34 can be rotated and folded relative to the first telescopic rod 31, and the second folding rod 35 and the second telescopic rod 32 can be rotated and folded, further increasing the space for the curvature change of the magnetic chuck 10 in the first and second directions.

Further, as shown in FIG. 6, in one embodiment, the connecting bracket 30 includes four L-shaped brackets 36. Each L-shaped bracket 36 includes the first telescopic rod 31 and the second telescopic rod 32 that are connected to each other. Two ends of the first folding rod 34 are respectively connected to the first telescopic rod 31 and the corner magnetic block 12. The two ends of the second folding rod 35 are respectively connected to the second telescopic rod 32 and the mechanical arm 20. The four L-shaped brackets 36 form an I-shaped bracket.

Specifically, as shown in FIG. 7, in one embodiment, the magnetic chuck 10 includes a central control board 13, the magnetic block 11 is an electromagnetic chuck, and the central control board 13 is electrically connected to the magnetic block 11 to control the magnetic force of the magnetic block 11.

The central control board 13 is located at the center of the magnetic chuck 10. The multiple magnetic blocks 11 are arranged around the central control board 13 along the first and second directions. The multiple magnetic blocks 11 adjacent to the central control board 13 are hinged to the central control board 13. The central control board 13 is ball-connected to the mechanical arm 20.

The size of the central control board 13 can be the same as or slightly larger than that of the magnetic block 11. The central control board 13 also serves as the center for changing the curved shape of the magnetic chuck 10. After the central control board 13 is connected to the mechanical arm 20, the connection angle between the central control board 13 and the mechanical arm 20 can be changed, that is, the angle between the magnetic chuck 10 and the shell of the ship 60 can be changed, further improving the fit between the magnetic chuck 10 and the shell of the ship 60.

Optionally, in one embodiment, the magnetic block 11 located at the center of the magnetic chuck 10 is a central magnetic block 11, and one end of the mechanical arm 20 is ball-connected to the magnetic block 11 located at the center of the magnetic chuck 10.

Specifically, as shown in FIG. 8 and FIG. 9, in one embodiment, the ship mooring stability auxiliary structure 100 includes an energy storage device 41, a permanent magnet 221 and an electromagnetic coil 222 sleeved on the permanent magnet 221 are disposed on the telescopic drive component 22, the energy storage device 41 is connected to the electromagnetic coil 222 and the telescopic drive component 22 respectively, and used to store electrical energy generated by the electromagnetic coil 222 and supply the stored electrical energy to the telescopic drive component 22.

Since the telescopic drive component 22 is equipped with the permanent magnet 221 and the electromagnetic coil 222, when the ship 60 sways back and forth along the water, the telescopic drive component 22 extends and retracts with the amplitude of sway. At this time, the electromagnetic coil 222 cuts a magnetic field lines generated by the permanent magnet 221, thereby generating electrical energy which is transmitted to the energy storage device 41. The energy storage device 41 then uses the stored electrical energy to drive the telescopic drive component 22, realizing energy recovery and reuse, and saving energy consumption of the ship mooring stability auxiliary structure 100.

In this specific embodiment, the controller 40 is electrically connected to the energy storage device 41 and the telescopic drive component 22, and is used to control the charging and discharging of the energy storage device, while controlling the driving force of the telescopic drive component.

Specifically, as shown in FIG. 9, in one embodiment, the magnetic chuck 11 is equipped with a pressure sensor, and the ship mooring stability auxiliary structure 100 includes a controller 40. The controller 40 is connected to the pressure sensor and the magnetic chuck 10 respectively, and is used to control opening and closing of the magnetic chuck 10 according to a detection value of the pressure sensor.

In this specific embodiment, the controller 40 is electrically connected to the central control board 13.

Specifically, as shown in FIG. 4, in one embodiment, the mechanical arm 20 is equipped with a protective cover 23. The protective cover 23 includes hard shells 231 sleeved on the different arm segments 21, protective cloth 232 connecting the multiple adjacent hard shells 231, and a telescopic corrugated pipe 233 sleeved on the telescopic drive component 22.

The hard shell 231 covers the outside of the mechanical arm 20 to protect the main body of each arm segment 21; the telescopic corrugated pipe 233 is wrapped around the outside of each telescopic drive component 22 and can extend and retract accordingly with the extension and retraction of the telescopic drive component 22; the protective cloth 232 is set at the connection parts of different arm segments 21 of the mechanical arm 20 to protect the connection mechanism and can deform with the relative rotation between the arm segments 21.

As shown in FIG. 1 and FIG. 2, in one embodiment, a harbor tugboat 50 is provided, including the tugboat 50 and the ship mooring stability auxiliary structure 100. The mechanical arm 20 of the ship mooring stability auxiliary structure 100 is connected to the tugboat 50, and the magnetic chuck 10 of the ship mooring stability auxiliary structure 100 is used for magnetic connection with the moored ship 60.

The aforementioned harbor tugboat 50 is connected to the magnetic chuck 10 and the tugboat 50 by the mechanical arm 20 disposed in the ship mooring stability auxiliary structure 100, and the magnetic chuck 10 is connected to the ship 60, thus realizing the connection between the tugboat 50 and the ship 60. Since the tugboat 50 is connected to the ship 60 by using the magnetic chuck 10, the tightness of the connection between the tugboat 50 and the ship 60 can be changed by adjusting the magnetic force of the magnetic chuck 10. The connection or disconnection between the tugboat 50 and the ship 60 can also be controlled by on/off control of the magnetic chuck 10. Further, the mechanical arm 20 includes the plurality of arm segments 21 that are hinged in sequence, and telescopic drive component 22 is provided between the arm segments 21. Therefore, the multiple telescopic drive components 22 can control the length and height of the mechanical arm 20 by extending and retracting different lengths, thereby controlling a connection position between the magnetic chuck 10 and the ship 60. The telescopic drive components 22 can also extend and retract with a amplitude of swaying when the ship 60 sways back and forth along the water. Meanwhile, the magnetic chuck 10 includes the multiple magnetic blocks 11, which are hinged to each other to form a flexible magnetic chuck 10 with a variable shape, which can adapt to a curved shell of the ship 60 and make the connection between the magnetic chuck 10 and the ship 60 more reliable. Therefore, the ship mooring stability auxiliary structure 100 can control the connection position between the magnetic chuck 10 and the ship 60 according to a mooring situation, and adjust the shape of the magnetic chuck 10 according to the curved shell of the ship 60, so as to facilitate the tugboat 50 to assist the ship 60 in mooring, which is conducive to improving the mooring stability of the ship 60.

As shown in FIG. 10, in one embodiment, a control method for a ship mooring stability auxiliary structure 100 is provided, the ship mooring stability auxiliary structure 100 including a tugboat 50, a mechanical arm 20, and a magnetic chuck 10 connected in sequence, the mechanical arm 20 including a plurality of arm segments 21 hinged in sequence, a telescopic drive component 22 being disposed between the two adjacent arm segments 21, and a controller being electrically connected to the tugboat 50, the telescopic drive component 22 and the magnetic chuck 10, wherein the control method of the controller 40 includes the following specific steps:

• • S10: obtaining design breaking force of a ship 60 mooring cable and ship 60 dimensions;
  • S20: setting tugboat 50 auxiliary thrust, an auxiliary quantity, and an auxiliary connection position of the magnetic chuck 10 to a ship 60;
  • S30: starting the auxiliary thrust and the tugboat 50 of the auxiliary quantity, and connecting the magnetic chuck 10 to the ship 60 according to the auxiliary connection position;
  • S40: calculating post-assistance maximum tension of the mooring cable according to the ship 60 dimensions, the auxiliary thrust, the auxiliary quantity, and the auxiliary connection position;
  • S50: determining whether the ship 60 is safe to moor according to the design breaking force and the post-assistance maximum tension of the mooring cable; and
  • S60: if the ship 60 is not safe to moor, adjusting the auxiliary thrust and the auxiliary connection position, and repeating steps S20 to S50 until it is determined that the ship 60 is safe to moor.

The aforementioned control method for the ship mooring stability auxiliary structure 100 can obtain the post-assistance maximum tension of the mooring cable through the ship dimensions, auxiliary thrust, auxiliary quantity, and auxiliary connection position. By comparing the design breaking force of the mooring cable with the post-assistance maximum tension, whether the ship 60 is safe to moor can be determined. By continuously adjusting the auxiliary thrust and auxiliary connection position, positive feedback of the ship mooring stability auxiliary structure 100 can be achieved until the ship 60 is safe to moor. This method is beneficial for adapting to different wind loads, wave loads, and water flow loads when the ship 60 is moored.

Specifically, in one embodiment, in step S40, the auxiliary quantity of tugboats 50 is set according to port environmental load conditions, ship model, draft, load, and other conditions. Among them, the port environmental load conditions mainly include wind loads, wave loads and water flow loads.

Specifically, in one embodiment, step S60 further includes the following steps:

• • adjusting the auxiliary connection position by controlling the telescopic drive component 22. That is, by controlling the length of the telescopic drive component 22 between different arm segments 21, the relative distance, horizontal position, and height position of the magnetic chuck 10 and the ship 60 can be adjusted.

Specifically, in one embodiment, between step S10 and step S20, the control method further includes the following steps:

• • step S11: obtaining pre-assistance maximum tension of the mooring cable when the ship 60 is moored;
  • step S12: determining whether the ship 60 is safe to moor according to the design breaking force and the pre-assistance maximum tension of the mooring cable; and
  • step S13: if the ship 60 is safe to moor, determining that no stability auxiliary structure is needed; otherwise, determining that the stability auxiliary structure is needed, and performing steps S20 to S60.

Before using the ship mooring stability auxiliary structure 100, the design breaking force of the mooring cable and the pre-assistance maximum tension can be used at first to determine whether the ship is safe to moor. If it is safe, the ship mooring stability auxiliary structure 100 is not needed to assist in mooring, which helps to save auxiliary energy consumption. If it is not safe, the auxiliary structure will be started. The determination criteria are clear, which helps to control the ship mooring stability auxiliary structure 100.

Specifically, in one embodiment, step S12 includes the following steps:

• • when the pre-assistance maximum tension satisfies the following relationship: F₁≤βF_s, where F_s is the design breaking force of the mooring cable, F₁ is the pre-assistance maximum tension of the mooring cable, β is a safety factor satisfying 45%≤β≤75%.
  • β is the safety factor, which is related to the material of the mooring cable and user requirements. Different users have different requirements. For example, the MEG4 published by OCIMF requires 55% for steel cables, 50% for syn-thetic fiber cables, and 45% for polymer cables. The users can choose the value of the safety factor β according to their own needs.

Specifically, in one embodiment, before step S20, the control method further includes the following specific steps:

• • obtaining a tugboat model and obtaining the auxiliary thrust of the tugboat 50 according to the tugboat model.

The tugboat model determines the maximum and minimum auxiliary thrust that the tugboat 50 can have. Therefore, when setting the auxiliary thrust of the tugboat 50, suitable auxiliary thrust can be selected within the range of the maximum and minimum auxiliary thrust.

Specifically, in one embodiment, in step S20, the auxiliary connection position between the magnetic chuck 10 and the ship 60 includes a horizontal distance and a vertical distance between a center point of the magnetic chuck 10 and a center of gravity of the ship 60, as well as a distance between center points of the two adjacent tugboats 50.

Specifically, in one embodiment, in step S20, the ship 60 dimensions include a ship modeled length and a ship modeled depth.

Further, in one embodiment, in step S40, when the tugboat 50 quantity is 1, the post-assistance maximum tension of the mooring cable satisfies the following relationship:

F 2 = exp ⁢ ( 2.02 ) · ( 3.65 · y D - 0.06 · x L ) · f

• • where: F₂ is the post-assistance maximum tension of the mooring cable, x is the horizontal distance between the center point of the magnetic chuck 10 and the center of gravity of the ship 60, y is the vertical distance between the center point of the magnetic chuck 10 and the center of gravity of the ship 60, L is the ship modeled length, D is the ship modeled depth, and f is the auxiliary thrust of the tugboat 50.

Further, in one embodiment, in step S40, when the tugboat 50 quantity is greater than 1, the post-assistance maximum tension of the mooring cable satisfies the following relationship:

F 2 = exp ⁡ ( 1 . 9 ⁢ 1 ) · { 3.65 · [ sum ( l n ) L ] - 1.13 · [ average ( x n ) L ] + 2.68 · [ average ( y n ) D ] } · f

F₂ is the post-assistance maximum tension of the mooring cable, x_n is the horizontal distance between the center point of the magnetic chuck 10 of the n-th tugboat 50 from left to right and the center of gravity of the ship 60, y_n is the horizontal distance between the center point of the magnetic chuck 10 of the n-th tugboat 50 from left to right and the center of gravity of the ship 60, l_n is the distance between the center points of the n-th tugboat and the adjacent tugboat 50 on the right, L is the ship 60 modeled length, D is the ship 60 modeled depth, and f is the auxiliary thrust of the tugboat 50.

Specifically, in one embodiment, step S50 includes the following steps:

• • when the post-assistance maximum tension satisfies the following relationship: F₂≤βF_s, where F_s is the design breaking force of the mooring cable, F₂ is the post-assistance maximum tension of the mooring cable, β is a safety factor satisfying 45%≤β≤75%.
  • β is the safety factor, which is related to the material of the mooring cable and user requirements. Different users have different requirements. For example, the MEG4 published by OCIMF requires 55% for steel cables, 50% for syn-thetic fiber cables, and 45% for polymer cables. The users can choose the value of the safety factor β according to their own needs.

Further, in one embodiment, after step S30, the control method further includes the following steps:

• • obtaining a motion amplitude of the ship 60; and
  • controlling damping force of the telescopic drive component 22 according to the motion amplitude of the ship 60.

The motion amplitude of ship 60 may include the maximum distance of forward and backward, and left and right swaying of the ship 60. The greater the motion amplitude, the smaller the damping force of the telescopic drive component 22.

The telescopic drive component 22 can be a pneumatic telescopic cylinder or a hydraulic telescopic cylinder. This paper chooses a hydraulic telescopic cylinder, which has stronger telescopic driving force. Therefore, different damping forces can be obtained by controlling the hydraulic pressure of the telescopic drive component 22, thereby achieving the swaying that follows the motion amplitude of the ship 60.

Further, in one embodiment, the magnetic chuck 10 includes an electromagnetic chuck 10 and a pressure sensor. In step S30, connecting the magnetic chuck 10 to the ship 60 according to the auxiliary connection position includes the following steps:

• • moving, by the mechanical arm 20, the magnetic chuck 10 to the auxiliary connection position;
  • obtaining a detection value of the pressure sensor; and
  • when the detection value of the pressure sensor tends to be stable, determining that the magnetic chuck 10 has made contact with the ship 60, starting the magnetic chuck 10, allowing the magnetic chuck 10 to adhere to and connect with the ship 60.

In this specific embodiment, the magnetic chuck 10 is an electromagnetic chuck, with a central control board disposed at the center position. The central control board controls opening and closing of magnetic force of the magnetic chuck 10 and size adjustment of the magnetic force.

In one embodiment, a mooring condition is a polymer mooring cable with design breaking force (F_s) of 1600 kN. Taking the moored ship 60 as an example, which is a 15 KTEU outfitting container ship with a molded length (L) of 367 m and a molded depth (D) of 29.9 m, the pre-assistance maximum tension F₁ of the mooring cable is as high as 1393.29 kN, which exceeds 75% of the breaking force, i.e., 1200 kN. There is a risk of cable breakage, and the mooring of ship 60 is unsafe. To ensure the safety of the moored ship 60, if three harbor tugboats 1 are dispatched to assist in the mooring of ship 60, the spacing (l_n) between each harbor tugboat should be l₁=l₂=10 m. The horizontal distance (x_n) between the midpoint of the line connecting the magnetic chucks 10 on each harbor tugboat from left to right and the center of gravity of the moored ship 60 should be x₁=20 m, x₂=0 m, and x₃=20 m respectively, and the vertical distance (y_n) should be y₁=y₂=y₃=4 m. The auxiliary thrust of tugboat 50 on the moored ship 60 is f=600 kN. At this time, the post-assistance maximum tension F₂ of the mooring cable is calculated to be 1046.16 kN, which is far below 75% of the breaking force, and the mooring of ship 60 is safe.

In the description of the present disclosure, it should be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “upper”, “lower”, “front”, “rear”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inner”, “outer”, “clockwise”, “counterclockwise”, “axial”, “radial”, and “circumferential” indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present disclosure.

Further, 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 at least one of those features. In the description of the present disclosure, “a plurality of” means at least two, such as two, three, etc., unless otherwise explicitly specified.

In the present disclosure, unless otherwise explicitly specified and limited, the terms “installation”, “connection”, “linking”, “fixing”, etc., should be interpreted broadly. For example, they may refer to fixed connection, detachable connection, or an integral part, may be mechanical connection or electrical connection, may be direction connection or indirect connection through an intermediate medium, and may be internal connection between two components or interactions between two components, unless otherwise explicitly defined. Those of ordinary skill in the art can understand the specific meaning of the above terms in the present disclosure according to the specific circumstances.

In the present disclosure, unless otherwise explicitly specified and limited, the first feature being “on” or “below” the second feature may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being “above”, “above” or “on top” of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. The first feature being “below”, “under”, or “below” the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

It should be noted that when a component is referred to as “fixed to” or “set on” another component, it can be directly on the other component or it can be located in between the component. When a component is considered to be “connected” to another component, it can be directly connected to the other component or there may be an intervening component present. The terms “vertical”, “horizontal”, “up”, “down”, “left”, “right”, and similar expressions used in this document are for illustrative purposes only and do not represent the only possible implementation.

The preferred embodiments of the present disclosure have been described in detail above. It should be understood that those of ordinary skill in the art can make numerous modifications and variations based on the concept of the present disclosure without creative effort. Therefore, any technical solution that can be obtained by those skilled in the art based on the concept of the present disclosure and through logical analysis, reasoning, or limited experimentation on the basis of the prior art should be within the scope of protection defined by the claims.