A wave compensation gangway that uses a wire rope to sense the relative motion of the ship

Abstract

The present invention relates to a wave compensation gangway that senses the relative movement of ships with a wire rope. A wave compensation main winch and an auxiliary induction winch are installed on the telescopic folding ladder device. During use, the telescopic folding ladder device is turned outboard and the ladder of the conventional gangway ladder assembly is extended outward to the required position by telescoping. The wire rope of the auxiliary induction winch thereon is fixed to the deck of the other ship considering the position. The auxiliary induction winch senses the change in the deck height difference between the two ships through the tightness of the wire rope, and inputs the calculated compensation speed parameter to the wave compensation main winch. The wave compensation main winch drives the conventional gangway assembly to move up and down according to the input parameter, which can ensure that a reasonable height difference is always automatically maintained between the lower platform of the conventional gangway assembly and the other ship, realizing the wave compensation function. The present invention is improved on the basis of the conventional gangway, retaining the advantages of the conventional gangway such as small volume, low cost, and simple system, while enabling it to adapt to higher sea conditions.

Description

Technical Field

[0001] The present invention relates to a gangway suitable for ships such as supply ships, personnel transport ships, salvage ships and even ordinary merchant ships that need to carry out personnel transfer operations at sea, and in particular to a gangway used for personnel transfer at sea under certain sea conditions. Background Art

[0002] 1. Maritime personnel transfer refers to the operation of transporting and receiving personnel from a ship carrying embarkation equipment (hereinafter referred to as the "mother ship") to another ship (hereinafter referred to as the "other ship"). The two ships should generally complete the docking before carrying out the personnel transfer.

[0003] 2. The common boarding equipment carried by ships includes gangways, pilot ladders and gangways. Gangways and pilot ladders are used when the freeboard difference between the two ships is large, while gangways can only be used when the freeboard difference between the two ships is small. In high sea conditions, the platform below the gangway is set up on another ship and is easily affected by the movement between the two ships, which may cause damage to the gangway and also affect the safety of boarding personnel. Therefore, if personnel transfer is required in high sea conditions, it is generally completed by pilot ladder. However, this boarding method has a high risk factor and requires a high level of physical fitness for boarding personnel.

[0004] 3. Currently, there is no simple solution to the problem of ship wave motion when transferring personnel between two ships in high sea conditions. There are two main solutions to solve the difficulty of transferring personnel or items at sea due to ship wave motion: one is to install a wave-compensating gangway on a wind turbine installation vessel, such as a wind turbine installation vessel, and then dock with the offshore wind turbine platform to transfer personnel. However, this solution occupies a large space, and the wave compensation uses motion attitude sensors to sense motion input, which has high procurement costs. For reference, patent publication number CN114872837A discloses a wave-compensating gangway system and its control method. The other is the wave-compensating crane widely used in marine operations, which also uses motion attitude sensors to sense motion input. The procurement cost is also high. Moreover, if the crane is used for lifting to transfer personnel, it needs to be certified as a man-lift crane, which complicates the ship inspection and testing procedures, and the design and construction costs will also increase dramatically.

[0005] 4. Patent publication number CN108045509A discloses a retractable gangway with wave compensation. However, the patent only describes the mechanical structure of the compensation and does not explain how the compensation signal input is obtained, which is not comprehensive enough. Therefore, it still does not solve the problem of transferring personnel when two ships are approaching each other in high sea conditions.

[0006] In summary, there is a lack of a small, low-cost, and simple solution for transferring people between two ships at sea. Existing solutions are large, low-cost, and complex.

[0007] Currently, various methods of transferring personnel at sea have various shortcomings. In comparison, the gangway occupies a moderate volume, has a high efficiency in personnel transfer, and can be used to transfer personnel between ships with large freeboard differences. However, conventional gangway personnel transfer also faces the following problems:

[0008] 1. The gangway ladder is installed on the mother ship. After the gangway ladder is deployed, the lower platform of the gangway ladder should be as close as possible to the other ship. Otherwise, it will be very strenuous for the other ship's personnel to step up and down the platform when boarding the mother ship. However, both the other ship and the mother ship are moving in the waves, and the lower platform of the gangway ladder will inevitably collide with the deck of the other ship. Therefore, it is hoped that the gangway ladder has a wave compensation function, that is, the lower platform of the gangway ladder rises and falls synchronously with the ups and downs of the other ship, and try to ensure that the lower platform of the gangway ladder and the deck of the other ship are kept equal.

[0009] 2. Personnel transfers between two ships docked alongside each other differ from those to offshore platforms. During transfers, the offshore platform experiences relatively little motion in the waves, and some fixed and jack-up platforms even experience no motion. However, during docking, both vessels experience motion in the waves, requiring at least two motion sensors to detect the motion of the mother ship and the other vessel, respectively, and calculate their relative positions to provide feedback to the mother ship's boarding equipment for compensation. While this approach can achieve relatively high accuracy, it is complex and unreliable, making it unsuitable for widespread deployment.

[0010] 3. Although the wave-compensating walkway commonly used in marine engineering has been put into use, it still has problems: First, the design method of combining towers and bridges makes the entire system very large and heavy, which is only suitable for deployment on dedicated ships / platforms and is not suitable for most ships. Second, the entire system is expensive and is more prone to situations with high frequency of personnel transfers, which is not in line with the needs and purchasing capabilities of most ships.

[0011] 4. When two ships with a slightly larger displacement are berthing alongside each other, the space between the two ships is not tight and there is usually a fender. However, a conventional gangway is usually close to the side of the mother ship when operating outboard. Therefore, a conventional gangway is difficult to use for personnel transfer between ships with a slightly larger displacement.

[0012] 5. The transfer of personnel between two ships needs to pursue a certain level of efficiency. It is necessary for personnel to queue up quickly at the gangway without flow restrictions and without long waiting times. Therefore, high requirements are placed on the strength of the gangway and its supporting system. Summary of the Invention

[0013] In order to solve the technical problems of conventional gangways while avoiding the defects of large size, high cost and complex system of wave compensation gangways, the present invention proposes a wave compensation gangway that is improved on the basis of conventional gangways and uses steel wire ropes to sense the relative motion of the ship.

[0014] To achieve the above object, the technical solution of the present invention is: a wave compensation gangway that senses the relative movement of a ship with a steel wire rope, including a conventional gangway ladder assembly, a main wave compensation winch, an auxiliary induction winch, and a telescopic folding ladder device. The main wave compensation winch and the auxiliary induction winch are installed on the telescopic folding ladder device. During use, the telescopic folding ladder device is turned outboard and the ladder of the conventional gangway ladder assembly is extended outward to the required position through telescoping. The steel wire rope of the auxiliary induction winch is fixed to a suitable position on the deck of another ship. The auxiliary induction winch senses the change in the height difference between the decks of the two ships through the tightness of the steel wire rope, and inputs the calculated compensation speed parameter to the main wave compensation winch. The main wave compensation winch drives the conventional gangway assembly to move up and down according to the input parameters, which can ensure that a reasonable height is always automatically maintained between the lower platform of the conventional gangway assembly and the other ship, realizing the wave compensation function.

[0015] Furthermore, the conventional gangway assembly includes an upper platform, a ladder, a lower platform, and a pulley block. The upper platform is the link between the gangway and the mother ship. The ladder is the passage for people to go up and down. The lower platform is the last platform to board the other ship and also the first platform for the other ship to board the gangway. The pulley block is used for guiding the steel wire rope, and this steel wire rope can drive the conventional gangway assembly to move up and down.

[0016] Furthermore, the main wave compensation winch includes a main steel wire rope and a main winch body. The main steel wire rope bypasses the conventional gangway assembly through the pulley block and functions to drive the conventional gangway assembly up and down.

[0017] Furthermore, the main wave compensation winch uses a steel wire rope to bypass the pulley block on the conventional gangway assembly, and after receiving the movement instruction from the auxiliary induction winch, it winds and unwinds the steel wire rope according to an algorithm to make the conventional gangway assembly move up and down.

[0018] Furthermore, the auxiliary induction winch includes an auxiliary steel wire rope and an auxiliary winch body. After the telescopic folding ladder device is turned outboard, the auxiliary steel wire rope is connected to a firm object on the deck of the other ship and then starts to work.

[0019] Furthermore, after the steel wire rope of the auxiliary induction winch is connected to a firm position on the other ship, the tension of the steel wire rope of the auxiliary induction winch is kept unchanged. Through the constant tension function, the steel wire rope is continuously wound and unwound with the waves, and its winding and unwinding speed is recorded and a movement instruction is sent to the main wave compensation winch in real time.

[0020] Furthermore, when the position of the auxiliary steel wire rope is close to that of the lower platform, the change in the length of the steel wire rope sensed at the auxiliary steel wire rope is equal to the change in the height required for compensating the position of the lower platform.

[0021] Furthermore, the telescopic folding ladder device includes a fixed arm, a movable arm, a telescopic oil cylinder, and a swing oil cylinder. The fixed arm is fixed on the deck of the mother ship and is hinged to the telescopic oil cylinder through the swing oil cylinder. The telescopic oil cylinder is connected to the movable arm.

[0022] A method for using a wave compensation gangway that senses the relative motion of a ship with a wire rope, the steps of which are as follows: (1) After the two ships are berthed and fixed with mooring ropes, the telescopic oil cylinder is driven to turn the conventional gangway assembly from the vertical position to the horizontal position, and the main winch body pays out the rope passively;

[0023] (2) The telescopic oil cylinder remains stationary, and the main winch body pays out the rope actively, gradually lowering the ladder frame to an inclined position so that the lower platform is within the allowable range from the deck of the other ship, and the angle between the ladder frame and the horizontal plane is not greater than 55°. Record the rope length L paid out at this time. S ;

[0024] (3) The auxiliary winch body starts to release the auxiliary wire rope, which is connected to a firm object on the other ship. After the connection is completed, the auxiliary winch body is driven to tension the auxiliary wire rope, maintain the tension to the set value and activate the constant tension function;

[0025] (4) Observe that the constant tension function of the auxiliary winch body is running stably and can output the pay-in and pay-out speed V3 of the winch to the system. At this time, select to activate the wave compensation function;

[0026] (5) After receiving the wave compensation instruction, the main winch body takes the pay-in and pay-out speed V3 of the auxiliary wire rope and the initial rope length L S or the initial downward inclination angle θ as the input, and calculates the working speed V2 of the wave compensation main winch body according to the established algorithm for wave compensation work;

[0027] (6) After the operation is completed, turn off the wave compensation function, first recover some main wire ropes, then disconnect the connection between the auxiliary wire rope and the firm object, and continue to recover the main wire ropes to make the standard ladder frame return to the horizontal position.

[0028] (7) Subsequently, retract the telescopic oil cylinder to the innermost position, then use the swing oil cylinder to retract the movable arm to make the ladder frame stand up, and finally use the fastening device to fasten the ladder frame.

[0029] Further, the established algorithm includes: Let the horizontal distance from the center line of the turning mechanism of the gangway to the hinge connecting the upper half platform and the ladder frame be L1, the length of the connecting line between the main winch and the ladder frame when the wave compensation is activated be L2, and the initial downward inclination angle of the ladder frame when the wave compensation is activated be θ. By solving the triangle, calculate L2 based on the length of the released wire rope and then calculate θ.

[0030]

[0031] Let the vertical speed of the lower platform position of the gangway be V1, that is, the target compensation working speed, the vertical relative speed of the platform position of the other ship measured by the auxiliary sensing winch be V3, and the total length of the ladder frame be L3. Then there is:

[0032]

[0033] Assuming the driving speed of the heave compensation main winch is V2 and the movable pulley coefficient of the pulley group is λ, the actual movement speed of the winch wire rope and the ladder frame connection point along the wire rope direction is V2 / λ. For a pulley group with only one movable pulley, λ = 2;

[0034] The relationship between the driving speed V2 of the heave compensation main winch and the speed V3 monitored by the auxiliary induction winch is obtained as follows:

[0035]

[0036] make It is called the geometric coefficient, and we have:

[0037] V2=V3·λ·K

[0038] The working speed V2 of the heave compensation main winch body is calculated accordingly.

[0039] The beneficial effects of the present invention are:

[0040] 1. The present invention is improved on the basis of the conventional gangway ladder, retaining the advantages of the conventional gangway ladder such as small size, low cost and simple system, while making it adaptable to higher sea conditions.

[0041] 2. The present invention solves the problem that when two ships need to use a gangway to transfer personnel after docking, the gap between the platform under the gangway and the deck of the other ship changes drastically due to the inconsistent movement response of the two ships in the waves, which may cause a safety accident.

[0042] 3. The present invention uses the steel wire rope pulled by the winch to transmit the height difference between the two ship decks, and uses this as input information to drive the main winch to retract and release the cable, avoiding the process of installing motion attitude sensors on the decks of the mother ship and the other ship and then solving the height difference change through complex mathematical calculations.

[0043] 4. The present invention can rotate the gangway ladder outward by a certain angle so as to accommodate different gaps between two ships when docking.

[0044] 5. The telescopic device of the turnover mechanism of the present invention is driven by a hydraulic cylinder, so all the winches in the present invention can be selected from conventional electric winches or hydraulic winches.

[0045] 6. The ladder frame design of the present invention is the same as the design of the load-bearing part of the ladder turning device of the conventional gangway ladder, and does not affect its normal load level.

[0046] 7. The turning motion of the ladder device of this invention is driven by a hydraulic cylinder, rather than the winch-driven scheme of a conventional gangway ladder. This allows for a more rational winch layout and allows for a better focus on the wave compensation function. It also eliminates the need for a large amount of steel wire rope on the deck, resulting in a simpler layout.

[0047] 8. The ladder turning device and the ladder frame assembly of the present invention are similar to conventional accommodation ladders. Each step can bear a load of 735 N, meeting the requirements for a large flow of personnel to go up and down the accommodation ladder.

[0048] 9. Components such as the winch and the oil cylinder used in the present invention are all common open-air equipment in the shipbuilding industry, and no precision instruments such as high-precision sensors are used. Therefore, it has higher reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 is a simplified diagram of the wave compensation accommodation ladder of the present invention;

[0050] Figure 2 is Figure 1 the top view of

[0051] Figure 3 is Figure 1 the A-A cross-sectional view of

[0052] Figure 4 is the front view of the whole accommodation ladder;

[0053] Figure 5 is the top view of the whole accommodation ladder;

[0054] Figure 6 is Figure 4 the A-A sectional view of

[0055] Figure 7 is Figure 4 the A-A sectional view of

[0056] Figure 8 the geometric and motion relationship diagram of the accommodation ladder. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0057] The present invention will be further described below in conjunction with the drawings and embodiments.

[0058] As Figures 1 to 8 shown, a wave compensation accommodation ladder of the present invention that senses the relative motion of the ship with a steel wire rope includes:

[0059] a conventional accommodation ladder assembly 1, adopting the same form and material as the conventional accommodation ladder;

[0060] a wave compensation main winch 2, which can be driven by hydraulic pressure or an electric motor, has a larger torque than the winch of the conventional accommodation ladder, and can receive the signal of the wave compensation main winch to take in or pay out after the wave compensation mode is turned on. The winch has a function of counting the cable length;

[0061] The auxiliary induction winch 3 can be driven by hydraulic pressure or an electric motor, and has a constant tension function and a cable length counting function. It is fixed at a firm place on the deck of another ship (such as the ground ring 6) to sense the relative displacement between the two ships. When the height difference between the decks of the two ships is close, which tends to loosen the wire rope and reduce the winch tension, the auxiliary induction winch automatically takes in the rope and records the rope-taking speed; when the height difference between the decks of the two ships widens, which tends to tighten the wire rope and increase the winch tension, the auxiliary induction winch automatically pays out the rope and records the rope-paying speed.

[0062] The telescopic folding ladder device 4 is hydraulically driven, and the wave compensation main winch 2 and the auxiliary induction winch 3 are installed on the folding ladder device. It has two actions of flipping and telescoping, and is used to turn out the conventional accommodation ladder assembly 1 outside the ship for work. When recovering the accommodation ladder, the telescopic folding ladder device is retracted first, and then the conventional accommodation ladder assembly 1 is received to the horizontal position by the wave compensation main winch 2. Then the telescopic folding ladder device 4 is flipped so that its movable arm and the component 1 are both in the vertical position, and then the conventional accommodation ladder assembly 1 is fastened by the fastening device 5 to complete the work.

[0063] Furthermore, the conventional accommodation ladder assembly 1 can be subdivided into an upper platform 11, a ladder frame 12, a lower platform 13 and a pulley block 14. The upper platform 11 is the link between the accommodation ladder and the mother ship. The ladder frame 12 is the ladderway for people to go up and down. The lower platform 13 is the last platform to board another ship and also the first platform for another ship to board the accommodation ladder. The pulley block 14 is used for wire rope guiding, and the wire rope can drive the conventional accommodation ladder assembly 1 to move up and down.

[0064] The reference standards for the conventional accommodation ladder are: "GB / T 11701-2021 Basic Requirements for Marine Accommodation Ladders" and "CB / T 3976-2008 Double-section Fixed Arc-step Aluminum Accommodation Ladders".

[0065] Furthermore, the wave compensation main winch can be subdivided into a main wire rope 21 and a main winch body 22. The main wire rope 21 bypasses the conventional accommodation ladder assembly 1 through the pulley block 14 and functions to drive the conventional accommodation ladder assembly 1 up and down.

[0066] Furthermore, the auxiliary induction winch can be subdivided into an auxiliary wire rope 31 and an auxiliary winch body 32. After the telescopic folding ladder device is turned out of the ship, the auxiliary wire rope 31 is connected to the ground ring 6 on the deck of another ship and then starts to work.

[0067] Furthermore, since the position of the auxiliary wire rope 31 is close to that of the lower platform 13, it can be considered that the change in the wire rope length sensed at the auxiliary wire rope 31 is equal to the height change value required to compensate the position of the lower platform 13.

[0068] Furthermore, the telescopic ladder device 4 can be subdivided into a fixed arm 41, a movable arm 42, a telescopic cylinder 43 and a swing cylinder 44. The fixed arm 41 is fixed on the deck of the mother ship and is hinged to the telescopic cylinder 43 through the swing cylinder 44, and the telescopic cylinder 43 is connected to the movable arm 42.

[0069] Furthermore, a section perpendicular to the horizontal plane of the gangway ladder frame is made, such as Figure 8 As shown in the figure, the horizontal distance from the center line of the gangway's turnover mechanism to the hinge connecting the upper half of the platform and the ladder frame is L1. When wave compensation is turned on, the length of the line connecting the main winch and the ladder frame is L2. When wave compensation is turned on, the initial downward tilt angle of the ladder frame is θ. By solving the triangle, L2 and then θ can be calculated based on the length of the paid-out wire rope. Alternatively, an angle sensor can be installed to directly measure θ.

[0070]

[0071] Furthermore, assuming that the vertical velocity of the platform under the gangway is V1 (i.e., the target compensation working speed), the vertical relative velocity of the platform of the other ship measured by the auxiliary induction winch is V3, and the total length of the ladder is L3, then:

[0072]

[0073] Furthermore, assuming the heave compensation main winch's drive speed is V2 and the pulley coefficient of the pulley assembly is λ, the actual speed of the winch wire rope at the connection point with the ladder frame along the wire rope direction is V2 / λ. For a pulley assembly with only one movable pulley, λ = 2.

[0074] Furthermore, the relationship between the driving speed V2 of the heave compensation main winch and the speed V3 monitored by the auxiliary induction winch can be obtained as follows:

[0075]

[0076] Further, let It is called the geometric coefficient, and we have:

[0077] V2=V3·λ·K

[0078] Furthermore, when the movable arm 42 is leveled, the horizontal distance A between the center of the ladder frame and the rotating axis must be maintained. This ensures that the centerline of the ladder frame 12 maintains a safe distance B from the side of the mother ship to prevent the ladder from scraping against the side. Driving the telescopic cylinder 43 extends the center of the ladder frame outward by a horizontal distance C. At this point, the inner side of the lower platform 13 is at a distance D from the side of the mother ship, which should be greater than the distance between the two ships. Furthermore, according to standards, the inner width E of the ladder frame 12 should be no less than 0.6 meters.

[0079] Furthermore, the working sequence of the heave compensation gangway is as follows:

[0080] 1) Two ships are alongside each other, using fenders to prevent collision. After the mooring and cable guiding are completed, the telescopic oil cylinder 43 is driven to turn the conventional gangway assembly 1 from the vertical position to the horizontal position, and the main winch body 22 pays out the rope passively.

[0081] 2) The telescopic oil cylinder 43 remains stationary, and the main winch body 22 pays out the rope actively, gradually lowering the ladder frame 12 to the inclined position. Generally, it is appropriate that the distance between the lower platform 13 and the deck of the other ship is within about 0.6 meters. When the sea conditions are relatively rough, this clearance can be increased appropriately. However, the angle between the ladder frame 12 and the horizontal plane is generally not greater than 55°. Record the rope length L paid out at this time. S ;

[0082] 3) The auxiliary winch body 32 starts to release the auxiliary wire rope 31 and connects it to a firm object on the other ship, such as the deck eye 6. After the connection is completed, the auxiliary winch body 32 is driven to tension the auxiliary wire rope 31, maintain the tension to the set value, and activate the constant tension function.

[0083] 4) Observe that the constant tension function of the auxiliary winch body 32 is running stably and can output the pay-in and pay-out speed V3 of the winch to the system. At this time, select to activate the wave compensation function.

[0084] 5) After receiving the wave compensation command, the main winch body 22 takes the pay-in and pay-out speed V3 of the auxiliary wire rope 31 and the initial rope length L2 (or the initial downward inclination angle θ) as inputs, and calculates the working speed V2 of the main winch body 22 according to the established algorithm to perform wave compensation work.

[0085] 6) After the operation is completed, turn off the wave compensation function, and appropriately recover some of the main wire rope 21 as appropriate. Then, disconnect the connection between the auxiliary wire rope 31 and the deck eye 6, and continue to recover the main wire rope 21 to make the part 12 return to the horizontal position.

[0086] 7) Subsequently, retract the telescopic oil cylinder 43 to the innermost position, and then use the swing oil cylinder 44 to retract the movable arm 42, causing the ladder frame 12 to be erected. Finally, use the fastening device 5 to fasten the ladder frame 12.

Claims

1. A wave-compensating gangway that uses a steel wire rope to sense relative motion of a ship, characterized by: The utility model comprises a conventional gangway ladder frame assembly, a wave compensation main winch, an auxiliary inductive winch, and a telescopic ladder turning device. The wave compensation main winch and the auxiliary inductive winch are installed on the telescopic ladder turning device. During use, the telescopic ladder turning device is turned overboard and the ladder frame of the conventional gangway ladder frame assembly is moved outward to the required position through telescoping. The auxiliary inductive winch wire rope on the gangway ladder frame assembly is fixed to the deck of the other ship in a balanced position. The auxiliary inductive winch senses the change of the deck height difference between the two ships through the tightness of the wire rope, and inputs the calculated compensation speed parameter to the wave compensation main winch. The wave compensation main winch drives the conventional gangway ladder assembly up and down according to the input parameter, which can ensure that the lower platform of the conventional gangway ladder assembly and the other ship always automatically maintain a reasonable height difference, thereby realizing the wave compensation function; the wave compensation main winch The vehicle includes a main wire rope and a main winch body, wherein the main wire rope passes around the conventional gangway ladder assembly through a pulley block and drives the conventional gangway ladder assembly up and down; the wave compensation main winch uses a wire rope to pass around the pulley block on the conventional gangway ladder assembly, and after receiving the motion command from the auxiliary induction winch, it retracts and extends the wire rope according to the algorithm to make the conventional gangway ladder assembly move up and down; the auxiliary induction winch includes an auxiliary wire rope and an auxiliary winch body. After the telescopic ladder device is flipped outboard, the auxiliary wire rope is connected to a solid object on the deck of the other ship and then starts working; after the wire rope of the auxiliary induction winch is connected to a solid position on the other ship, the wire rope tension of the auxiliary induction winch is maintained unchanged. Through the constant tension function, the wire rope is continuously retracted and extended with the waves, and its retraction and extension speed is recorded, and the motion command is issued to the wave compensation main winch in real time.

2. The wave-compensating gangway using a steel wire rope to sense relative motion of a ship according to claim 1, characterized in that: A conventional gangway ladder assembly includes an upper platform, a ladder frame, a lower platform and a pulley block. The upper platform is the link between the gangway ladder and the mother ship, the ladder frame is the stairway for people to go up and down, and the lower platform is the last platform for boarding other ships and also the first platform for boarding the gangway ladder from other ships. The pulley block is used for guiding the wire rope, and the wire rope can drive the conventional gangway ladder assembly up and down.

3. The wave-compensating gangway using a steel wire rope to sense relative motion of a ship according to claim 1, characterized in that: When the auxiliary steel wire rope and the lower platform are close, the change in the length of the steel wire rope sensed at the auxiliary steel wire rope is equal to the height change value required to compensate for the lower platform position; when there is a certain distance between the auxiliary steel wire rope and the lower platform position, the height change value required to compensate for the lower platform position is converted through geometric relationships.

4. The wave-compensating gangway using a steel wire rope to sense relative motion of a ship according to claim 1, characterized in that: The telescopic ladder device includes a fixed arm, a movable arm, a telescopic cylinder and a swing cylinder. The fixed arm is fixed on the deck of the mother ship and is hinged to the telescopic cylinder through the swing cylinder. The telescopic cylinder is connected to the movable arm.

5. A method for using a wave compensation gangway that uses a steel wire rope to sense the relative motion of a ship, characterized in that: The steps are: (1) After the two ships are tied together and fixed with cables, the telescopic cylinder is driven to flip the conventional gangway assembly from a vertical position to a horizontal position, and the main winch body is driven to release the rope; (2) The telescopic cylinder remains stationary, and the main winch body actively releases the rope, gradually lowering the ladder frame to an inclined position so that the lower platform is within the allowable range from the deck of the other ship and the angle between the ladder frame and the horizontal plane is no more than 55°. Record the length of the rope released at this time, L S ; (3) The auxiliary winch starts to release the auxiliary steel wire rope to connect it to a solid object on the ship. After the connection is completed, the auxiliary winch body is driven to tighten the auxiliary steel wire rope, maintain the tension to the set value and turn on the constant tension function; (4) Observe that the constant tension function of the auxiliary winch body is running stably and can output the winch retraction and extension speed V3 to the system. At this time, choose to turn on the heave compensation function; (5) After receiving the wave compensation instruction, the main winch body adjusts the auxiliary wire rope according to the retraction speed V3 and the initial rope length L S Alternatively, the initial downtilt angle θ is used as input, and the operating speed V2 of the main wave compensation winch body is calculated according to a predetermined algorithm to perform wave compensation. The predetermined algorithm includes: assuming that the horizontal distance from the center line of the gangway's tilting mechanism to the hinge connecting the upper half of the platform and the ladder frame is L1, the length of the line connecting the main winch and the ladder frame when wave compensation is enabled is L2, and when wave compensation is enabled, the initial downtilt angle of the ladder frame is θ. By solving the triangle, L2 is calculated based on the length of the paid-out wire rope, and then θ is calculated. Assume that the vertical velocity of the platform under the gangway is V1, that is, the target compensation working speed, the vertical relative velocity of the platform of the other ship measured by the auxiliary induction winch is V3, and the total length of the ladder is L3, then: Assuming the driving speed of the heave compensation main winch is V2 and the movable pulley coefficient of the pulley group is λ, the actual movement speed of the winch wire rope and the ladder frame connection point along the wire rope direction is V2 / λ. For a pulley group with only one movable pulley, λ = 2; The relationship between the driving speed V2 of the heave compensation main winch and the speed V3 monitored by the auxiliary induction winch is obtained as follows: make It is called the geometric coefficient, and we have: V2=V3·λ·K The working speed V2 of the main heave compensation winch body is calculated accordingly; (6) After the operation is completed, turn off the wave compensation function, first retract some of the main wire rope, then untie the connection between the auxiliary wire rope and the solid object, and continue to retract the main wire rope to return the standard ladder to the horizontal position; (7) Then, retract the telescopic cylinder to the innermost position, and then use the swing cylinder to retract the movable arm, so that the ladder frame is erected, and finally use the fastening device to fasten the ladder frame.

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