CN119497692A

CN119497692A - Mooring Line Tension Monitoring System

Info

Publication number: CN119497692A
Application number: CN202380055205.7A
Authority: CN
Inventors: 风间英辉; 野田嵩; 大江启司; 森下笃志
Original assignee: Kawasaki Jukogyo KK
Current assignee: Kawasaki Motors Ltd
Priority date: 2022-08-04
Filing date: 2023-06-13
Publication date: 2025-02-21
Also published as: JP2024021895A; KR20250037551A; WO2024029205A1

Abstract

The mooring line tension monitoring system (1) of one embodiment is a system for monitoring the tension of a mooring line (10), the mooring line (10) being mounted on at least one mooring metal member (22) on a hull (21) and being tethered at the tip to a mooring post (31) of a fixed structure (3), the system comprising a mooring machine (4) comprising a reel around which the mooring line (10) is wound, and a control device (9). A control device (9) calculates the roll side tension P of a mooring rope (10), determines the tension attenuation rate R of the mooring rope (10) when the mooring rope is erected on at least one mooring metal piece (22), and calculates the column side tension P0 of the mooring rope (10) by multiplying the roll side tension P by the tension attenuation rate R or dividing the roll side tension P by the tension attenuation rate R.

Description

Mooring line tension monitoring system

Technical Field

The present disclosure relates to a mooring line tension monitoring system.

Background

When a ship is tied to a fixed structure such as a shore or an offshore base, a mooring line is mounted on at least one mooring metal on the hull, and the tip end of the mooring line is tied to a mooring post of the fixed structure. The mooring line is reeled in or unreeled by a mooring machine (strander) provided on the hull.

In the case of mooring, since the tension of the mooring line varies depending on the tide level, load capacity, wind, tide, and the like, it is desirable to monitor the tension of the mooring line. For example, patent document 1 describes a mooring machine including a drum around which a mooring line is wound, and a band brake that switches between a restrained state in which rotation of the drum is prohibited and an released state in which rotation of the drum is permitted, wherein when the band brake is in the restrained state, the tension of the mooring line is calculated from a detection value of a load sensor provided to the band brake and a tension application radius on the drum.

Patent document 2 describes using a fiber rope as a mooring line, twisting an elongation sensor at a tip end portion of the fiber rope, and calculating a tension of the mooring line from a detection value of the elongation sensor.

Prior art literature:

Patent literature:

patent document 1 Japanese patent laid-open publication No. 2002-211478

Patent document 2 International publication No. 2020/110902

Disclosure of Invention

Problems to be solved by the invention:

As described in patent document 1, when the tension of the mooring line is calculated based on the detection value of the load sensor provided to the band brake and the tension application radius on the drum, the calculated tension is the tension of the vicinity of the drum in the mooring line. As described above, since the mooring line is mounted to at least one of the mooring line pieces on the hull, the tension of the mooring line is different before and after the mooring line piece. That is, in the structure described in patent document 1, the tension at the portion between the dolphin and the dolphin in the most important dolphin cable, that is, the dolphin side tension cannot be detected.

In contrast, in the structure described in patent document 2, the dolphin side tension of the dolphin can be detected, but the elongation sensor must be twisted into the fiber rope.

It is therefore an object of the present disclosure to provide a hawser tension monitoring system that is capable of detecting the dolphin side tension of a hawser without the use of an elongation sensor.

Means for solving the problems:

a system for monitoring the tension of a mooring line which is supported by at least one mooring metal member on a ship body and whose tip is tied to a mooring post of a fixed structure, the system comprising a mooring machine which includes a drum around which the mooring line is wound, and a control device which calculates the tension of a portion between the mooring machine and the at least one mooring metal member in the mooring line, that is, drum side tension, and determines the tension attenuation rate of the mooring line which is supported by the at least one mooring metal member, and calculates the tension of the portion between the at least one mooring metal member and the mooring post in the mooring line, that is, the drum side tension, by dividing the drum side tension by the tension attenuation rate by the drum side tension.

The invention has the following effects:

according to the present disclosure, a hawser tension monitoring system is provided that is capable of detecting a dolphin side tension of a hawser without using an elongation sensor.

Drawings

FIG. 1 is a schematic block diagram of a mooring line tension monitoring system of one embodiment;

FIG. 2 is a front view of the ship lock;

Fig. 3 is a schematic configuration diagram of the band brake.

Detailed Description

A mooring line tension monitoring system 1 of one embodiment is shown in fig. 1. The mooring line tension monitoring system 1 monitors the tension of a mooring line 10 when a ship 2 is moored to a fixed structure 3 such as a shore wall or an offshore base by the mooring line 10.

Specifically, the mooring line tension monitoring system 1 includes a plurality of ship-tying machines 4 provided on the hull 21 of the ship 2, and a control device 9 that controls the ship-tying machines 4. Each ship lock 4 winds and unwinds the corresponding mooring line 10. In the present embodiment, four ship-tying machines 4 are arranged on the port and starboard sides on the bow side and the port and starboard sides on the stern side, but the number and positions of the ship-tying machines 4 may be changed as appropriate.

The hull 21 is provided with a plurality of anchor members 22, and the fixed structure 3 is provided with a plurality of anchor posts 31. When mooring, each mooring line 10 is mounted to at least one mooring metal member 22, and the tip end of mooring line 10 is tied to mooring post 31. In fig. 1, all of the mooring lines 10 are installed in two mooring line members 22, but the number of the mooring line members 22 installed in each of the mooring lines 10 may be one or three or more.

The dolphin metal 22 is, for example, a stand roller, a fairlead (fairlead), deck rollers (deck roller), bearing blocks (chock), etc. Bollard 31 is, for example, a bollard (bitt), a bollard (bollard), a quick release (quick release hook), or the like. The mooring line 10 may be a fiber rope or a metal wire. Examples of the material of the fiber rope include nylon, ultra high molecular weight polyethylene (HMPE), and the like. The mooring line 10 may also be formed with a fiber rope at the tip end and a wire for the most part.

As shown in fig. 2, each of the dolphins 4 includes a drum 7 around which a mooring line 10 is wound, and a motor 51 that rotates the drum 7. In fig. 2, the drawing of the mooring line 10 is omitted for simplicity of the drawing. The spool 7 is rotatably supported by a support table 25. In the present embodiment, a speed reducer 52 is provided between the motor 51 and the spool 7, and a clutch 53 and a band brake 6 are provided between the speed reducer 52 and the spool 7. That is, the motor 51 rotates the spool 7 via the speed reducer 52 and the clutch 53.

Motor 51 rotates in a first direction where mooring line 10 is reeled into drum 7 and in a second direction where mooring line 10 is unreeled from drum 7. In the present embodiment, the motor 51 is a hydraulic motor, and the hydraulic oil is supplied and discharged through the control valve 55. The control valve 55 is controlled by the control device 9, and thereby the stop of the motor 51, the rotation in the first direction, and the rotation in the second direction are switched. However, the motor 51 may be an electric motor and may be directly controlled by the control device 9.

The motor 51 is provided with a torque detector 50 for detecting the torque of the motor 51. In the present embodiment, since the motor 51 is a hydraulic motor, a pressure sensor that measures the inflow pressure of the hydraulic oil supplied to the hydraulic motor is used as the torque detector 50, and the inflow pressure measured by the pressure sensor is converted into the torque of the motor 51. Instead of the pressure sensor, a torque sensor that directly measures the torque of the motor 51 may be employed. Alternatively, in the case where the motor 51 is an electric motor, the current flowing to the electric motor may be converted into a torque.

The clutch 53 is switched between a fitted state in which the spool 7 is coupled to the speed reducer 52 and a disengaged state in which the spool 7 is separated from the speed reducer 52. In the present embodiment, the clutch 53 includes a hydraulic cylinder. The hydraulic cylinder is connected to a solenoid valve 81, and the solenoid valve 81 is controlled by the control device 9, whereby the clutch 53 is switched from the engaged state to the disengaged state or vice versa. However, instead of a hydraulic cylinder, the clutch 53 may also comprise an electric cylinder, which is controlled directly by the control device 9.

The band brake 6 is switched between a restrained state in which rotation of the spool 7 is prohibited and an opened state in which rotation of the spool 7 is permitted. In the present embodiment, as shown in fig. 3, the band brake 6 includes a hydraulic cylinder 66. The hydraulic cylinder 66 is connected to a solenoid valve 82 (see fig. 2), and the solenoid valve 82 is controlled by the control device 9, whereby the band brake 6 is switched from the restrained state to the opened state or vice versa. However, instead of the hydraulic cylinder 66, the band brake 6 may also comprise an electric cylinder, which is controlled directly by the control device 9.

More specifically, the band brake 6 includes a brake drum 61 that rotates together with the spool 7, and a pair of arcuate bands 62, 63 that extend along the brake drum 61. One ends of the belts 62 and 63 are connected via pins 64, and the other ends of the belts 62 and 63 are connected to the hydraulic cylinder 66 via a link mechanism 65. When the hydraulic cylinders 66 move the other ends of the belts 62 and 63 away from each other via the link mechanism 65, a small gap is formed between the belts 62 and 63 and the brake drum 61, and the band brake 6 is opened. Conversely, when the hydraulic cylinders 66 approach the other ends of the belts 62 and 63 via the link mechanism 65, the belts 62 and 63 fasten the brake drum 61, and the band brake 6 is in the restrained state.

The band brake 6 is provided with a load sensor (load cell) 60 that detects the band tension F applied to the bands 62 and 63 in the restrained state. In the present embodiment, a pin-type load cell 60 is used. The link mechanism 65 includes a tension rod 67, and the tension rod 67 is coupled to a bracket 23 provided on the hull 21 via a load sensor 60.

An operation signal is inputted to the control device 9 for each ship lock 4. Based on the input operation signal, control device 9 controls control valve 55 and solenoid valves 81 and 82 of corresponding dolphin 4. For example, the control valve 55 includes an operation lever so that the crew member can manually operate the ship lock 4, and an operation signal corresponding to the tilting direction is input to the control device 9 when the operation lever is tilted. Alternatively, in the case of automatic steering, the control device 9 may generate an operation signal itself.

The functions of the elements disclosed in the present specification can be executed using a circuit or a processing circuit including a general-purpose processor, an Application-specific processor, an integrated circuit, an ASIC (Application SPECIFIC INTEGRATED Circuits), an existing circuit, and/or a combination thereof, which are configured or programmed to execute the disclosed functions, with respect to the control device 9. The processor includes transistors and other circuitry and so may be considered processing circuitry or circuitry. In this disclosure, a circuit, unit, or means is hardware that performs the recited function or is hardware programmed to perform the recited function. The hardware may be the hardware disclosed in this specification or may be other known hardware programmed or configured to perform the recited functions. When hardware is a processor that is considered to be one of the circuits, a circuit, means, or unit is a combination of hardware and software, the software being used for the construction of the hardware and/or the processor.

The control device 9 is electrically connected to the torque detector 50 and the load sensor 60. In the present embodiment, the control device 9 is also electrically connected to the roll layer number detector 70 and the two cameras 91 (see fig. 1). The number of layers of the rolls of the hawser 10 on the drum 7 is detected by the number of layers of the rolls detector 70. For example, the number of winding layers detector 70 converts the position of the outermost peripheral surface of the mooring line 10 wound around the drum 7 into the number of winding layers.

One of the two cameras 91 captures an area including two dolphins 4 arranged on the bow side and all of the dolphin metal pieces 22 that the dolphins 10 extending from these dolphins 4 may be erected, and the other camera 91 captures an area including two dolphins 4 arranged on the stern side and all of the dolphin metal pieces 22 that the dolphins 10 extending from these dolphins 4 may be erected.

Based on the detection results of torque detector 50, load sensor 60, and number of winding layers detector 70, and the image of camera 91, control device 9 calculates a tension at a portion between dolphin metal 22 and dolphin 31 in each dolphin cable 10, that is, a dolphin side tension P0.

First, control device 9 calculates spool-side tension P, which is the tension at the portion between dolphin 4 and dolphin metal 22 in each hawser 10. Specifically, the control device 9 calculates the spool-side tension P based on the torque T of the motor 51 detected by the torque detector 50 and the number of winding layers N detected by the winding-layer-number detector 70 when the band brake 6 is in the open state. For example, the control device 9 calculates the roll-side tension P using the following equation (1).

[ Mathematics 1]

,

R reduction ratio of speed reducer 52 [ - ]

Eta W mechanical efficiency of the mooring machine 4 [ - ]

DR diameter of hawser 10 [ mm ]

DD diameter of the reel 7 [ mm ].

Conversely, when the band brake 6 is in the restrained state, the control device 9 calculates the roll-side tension P based on the band tension F detected by the load sensor 60 and the number of winding layers N detected by the winding-layer-number detector 70. For example, the control device 9 calculates the roll-side tension P using the following equation (2).

[ Math figure 2]

,

L-horizontal distance [ mm ] from the centre of the reel 7 to the load cell 60.

Next, control device 9 determines a tension attenuation rate R generated by erecting mooring line 10 on mooring metal fitting 22 for each mooring line 10. In the determination of the tension attenuation rate R, the image of the camera 91 is used.

Control device 9 determines, based on the image captured by camera 91, which mooring line 10 is to be mounted on, and the angle at which mooring line 10 is to be wound around each mooring line 22. Then, the control device 9 calculates the individual attenuation rate Ri for each of the dolphin fittings 22 on which each of the dolphins 10 is mounted. In addition, "i" refers to the number of the dolphin fitting 22 on which one dolphin cable 10 is mounted. For example, the control device 9 calculates the individual attenuation ratio Ri using the following equation (3).

[ Math 3]

,

Μi coefficient of friction associated with ith dolphin metal piece 22

Θi-angle of wrap of hawser 10 relative to ith hawser 22

That is, the individual damping rate Ri of the ith dolphin 22 is calculated using the friction coefficient μi and the winding angle θi.

The coefficient of friction μi is a coefficient corresponding to the type of the ith dolphin metal 22 and the type of the dolphin cable 10 to be mounted on the ith dolphin metal 22. The control device 9 stores in advance a friction coefficient table defining a correspondence relation between the type of the mooring metal fitting 22 and the type (material and diameter) of the mooring line 10 and the friction coefficient, and the control device 9 determines the friction coefficient μi of the ith mooring metal fitting 22 based on the type of the mooring line 10 stored in advance and the image of the camera 91 using the friction coefficient table. The friction coefficient table in the case where the dolphin metal 22 is a bearing housing is shown in table 1, for example.

TABLE 1

。

When there is one of the dolphin fittings 22 to be installed in the dolphin 10, the control device 9 determines the individual damping rate Ri of the dolphin fitting 22 as the tension damping rate R generated when the dolphin 10 is installed in the dolphin fitting 22. When there are a plurality of dolphin fittings 22 to which the dolphin 10 is attached, the control device 9 multiplies the individual attenuation rates Ri of the dolphin fittings 22, and determines the multiplied value as a tension attenuation rate R generated when the dolphin 10 is attached to the dolphin fittings 22. That is, the control device 9 determines the tension attenuation rate R of the entire hawser 10 using the following equation (4).

[ Mathematics 4]

,

N the total number of dolphin pieces 22 erected by one dolphin 10.

Then, when the mooring line 10 is wound around the drum 7, the control device 9 multiplies the drum side tension P by the tension attenuation ratio R to calculate the dolphin side tension P0 (p0=p×r), and divides the drum side tension P by the tension attenuation ratio R when the mooring line 10 is unwound from the drum 7 and when the drum 7 is stopped to calculate the dolphin side tension P0 (p0=p/R). Therefore, by simply switching whether to multiply or divide the spool-side tension P by the tension attenuation ratio R, the dolphin-side tension P0 at the time of reeling in the dolphin and the dolphin-side tension P0 at the time of unreeling the dolphin and at the time of stopping the spool can be calculated.

As described above, in the hawser tension monitoring system 1 of the present embodiment, since the roll side tension P is converted into the dolphin side tension P0 using the tension attenuation rate R, the dolphin side tension P0 of the hawser 10 can be detected without using an elongation sensor.

In the present embodiment, since the tension attenuation ratio R is determined using the equation (4), the tension attenuation ratio R of the entire mooring line 10 can be calculated by calculating only the individual attenuation ratio Ri of each mooring metal member 22.

Further, since the individual damping rate Ri of each of the dolphin fittings 22 is calculated using the friction coefficient μi and the winding angle θi, the individual damping rate Ri can be calculated using the same mathematical expression.

(Modification)

The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

For example, instead of using the number of winding layers detector 70, a split reel including a storage reel and a tension reel may be used as the reel 7, and the mooring line 10 may be wound around the tension reel at the time of mooring, so that the radius of the acting line from the center of the reel 7 to the tension is constant. However, in this case, the operation of winding the mooring line 10 around the tension drum is required at the time of mooring. In contrast, if the number of winding layers of the hawser 10 on the reel 7 is detected by the winding layer number detector 70, no special work is required at the time of the mooring operation, as in the case of using a split reel.

Further, depending on the vessel 2, the mooring metal member 22 to which the mooring line 10 is mounted may be predetermined. In this case, the camera 91 may not be required, and the winding angle of the mooring line 10 with respect to each of the mooring pieces 22 other than the mooring piece 22 located near the outline of the ship 2 may be stored in advance in the control device 9.

Further, regarding the winding angle of the mooring line 10 with respect to the mooring metal piece 22 located in the vicinity of the outline of the vessel 2, in other words, the closest mooring metal piece 22 to the dolphin 31 in the mooring metal piece 22 where the mooring line 10 is installed, the control device 9 may calculate the winding angle of the mooring line 10 with respect to the closest mooring metal piece 22 to the dolphin 31 based on the GPS information (latitude and longitude) of the vessel 2 and the terrain information (including latitude and longitude of the mooring post 31) of the fixed structure 3 stored in advance in the control device 9.

(Summary)

As a first aspect, the present disclosure provides a mooring line tension monitoring system that monitors a tension of a mooring line that is mounted on at least one mooring metal piece on a hull and whose tip is tied to a mooring post of a fixed structure, the system including a mooring line including a drum around which the mooring line is wound, and a control device that calculates a drum side tension, which is a tension of a portion between the mooring line and the at least one mooring metal piece, and determines a tension attenuation rate by which the mooring line is mounted on the at least one mooring metal piece, and calculates a tension of a portion between the at least one mooring metal piece and the mooring post in the mooring line, which is a mooring line side tension, by multiplying the drum side tension by the tension attenuation rate or dividing the drum side tension by the tension attenuation rate.

According to the above configuration, since the roll-side tension is converted into the dolphin-side tension using the tension attenuation rate, the dolphin-side tension of the hawser can be detected without using an elongation sensor.

In the second aspect, in the first aspect, the at least one mooring line metal piece may include a plurality of mooring line metal pieces, and the control device may calculate individual attenuation rates for the plurality of mooring line metal pieces, and may determine the tension attenuation rate generated when the mooring line is installed in the plurality of mooring line metal pieces by multiplying the individual attenuation rates of the plurality of mooring line metal pieces. According to this configuration, the individual damping rate of each of the mooring line fittings can be calculated, so that the tension damping rate of the entire mooring line can be calculated.

In a third aspect, in the second aspect, the control device may calculate the individual attenuation rate using a coefficient of friction corresponding to types of the mooring line and the mooring line fitting and a winding angle of the mooring line with respect to the mooring line fitting. According to this configuration, the individual attenuation ratio can be calculated using the same numerical expression.

In a fourth aspect, in any one of the first to third aspects, the control device may calculate the dolphin side tension by multiplying the roll side tension by the tension attenuation rate when the dolphin is wound around the roll, and calculate the dolphin side tension by dividing the roll side tension by the tension attenuation rate when the dolphin is unwound from the roll and when the roll is stopped. According to this configuration, the dolphin side tension at the time of reeling the dolphin cable and the dolphin side tension at the time of unreeling the dolphin cable and the time of stopping the reel can be calculated by simply switching whether the reel side tension is multiplied or divided by the tension attenuation rate.

In a fifth aspect, for example, in any one of the first to fourth aspects, the ship-mooring machine may include a motor that rotates the reel, and a band brake that switches between a restrained state in which rotation of the reel is prohibited and an open state in which rotation of the reel is permitted, wherein the control device calculates the reel side tension based on a torque of the motor when the band brake is in the open state, and calculates the reel side tension based on a band tension of the band brake when the band brake is in the restrained state.

Claims

1. A mooring line tension monitoring system, characterized in that,

Is a system for monitoring the tension of a mooring line that is mounted to at least one mooring metal member on the hull and is tethered at its tip to a mooring post of a fixed structure,

The system is provided with:

A ship lock comprising a drum around which the mooring line is wound, and

And a control device that calculates a roll-side tension, which is a tension of a portion between the at least one dolphin and the at least one dolphin in the dolphin, and determines a tension attenuation rate at which the dolphin is installed on the at least one dolphin, and calculates a dolphin-side tension, which is a tension of a portion between the at least one dolphin and the dolphin in the dolphin, by multiplying the roll-side tension by the tension attenuation rate or dividing the roll-side tension by the tension attenuation rate.

2. The hawser tension monitoring system of claim 1, wherein,

The at least one dolphin metal piece comprises a plurality of dolphin metal pieces,

The control device calculates individual damping rates for the plurality of dolphin metal pieces, and multiplies the individual damping rates for the plurality of dolphin metal pieces to determine the tension damping rate generated when the dolphin cable is installed on the plurality of dolphin metal pieces.

3. The hawser tension monitoring system of claim 2, wherein,

The control device calculates the individual attenuation rate using a coefficient of friction corresponding to the type of the mooring line and the mooring metal piece and a winding angle of the mooring line with respect to the mooring metal piece.

4. A mooring line tension monitoring system according to any of claims 1-3, wherein,

The control device calculates the dolphin side tension by multiplying the roll side tension by the tension attenuation rate when the dolphin is wound around the roll, and calculates the dolphin side tension by dividing the roll side tension by the tension attenuation rate when the dolphin is unwound from the roll and when the roll is stopped.

5. A mooring line tension monitoring system according to any of claims 1-3, wherein,

The bollard includes a motor that rotates the spool, and a band brake that switches between a restrained state that inhibits rotation of the spool and an open state that allows rotation of the spool,

The control device calculates the spool-side tension based on the torque of the motor when the band brake is in the open state, and calculates the spool-side tension based on the band tension of the band brake when the band brake is in the restrained state.