Sea gangway ladder preset time autonomous lap joint control system and working method thereof

Abstract

The invention discloses a marine gangway ladder preset time autonomous lap joint control system and a working method thereof. The system comprises an inertial measurement unit and a main control computer; the binocular camera is adopted, multi-sensor fusion is not needed, accurate lap joint point position information is directly obtained, and the method is simple and easy to implement; according to the provided preset-time autonomous lap joint control method, the system adjusting time can be set in advance, and operation and maintenance ship movement caused by waves is efficiently compensated by driving the swing mechanism, the pitching mechanism and the telescopic mechanism to cooperatively move, so that the front end of the offshore gangway ladder accurately follows the expected position of an upper lap joint point in time; the offshore accommodation ladder is lapped to the offshore wind turbine platform within the set lapping time, so that efficient and autonomous lapping of the offshore accommodation ladder and the offshore fixed or floating wind turbine platform is ensured, and the lapping efficiency is improved; the front end of the offshore gangway ladder is in non-contact lap joint with the lap joint point of the offshore wind turbine platform, no special requirement for the lap joint point exists, a landing device does not need to be built, and the maintenance and manufacturing cost of the gangway ladder is reduced.

Description

Technical Field

[0001] This invention relates to equipment control technology in the field of shipbuilding and marine engineering, and in particular to a pre-set time autonomous connection control system for marine gangways and its working method. Background Technology

[0002] To ensure the power generation efficiency of offshore wind farms, regular and professional maintenance of offshore wind turbines is necessary. Offshore gangways with wave compensation capabilities are installed on maintenance vessels equipped with dynamic positioning systems. By connecting the front end of the gangway to the offshore wind turbine platform, a safe, stable, and reliable transfer channel is established between the maintenance vessel and the offshore wind turbine for personnel and material transport, facilitating offshore wind power operation and maintenance work.

[0003] Chinese invention patent CN118811013A discloses a three-degree-of-freedom active wave compensation control method for a marine gangway. The method describes a marine gangway comprising a lifting platform, a slewing mechanism, a luffing mechanism, a telescopic mechanism, and a gangway frame. The slewing mechanism employs feedforward fuzzy adaptive PID correction control, the luffing mechanism employs cross-coupling synchronous control, and the telescopic mechanism employs feedforward PID correction control. The method compensates for the movement of the maintenance vessel through the coordinated action of the slewing mechanism, luffing mechanism, and telescopic mechanism, ensuring that the front end of the marine gangway remains stable in the desired position, thus guaranteeing that the front end of the marine gangway can be connected to a fixed offshore wind turbine platform. However, this method is not applicable to connecting to floating offshore wind turbine platforms.

[0004] Chinese invention patent CN113104153B discloses a wave compensation control system for a maritime transfer pier and its working method. The maritime pier in this invention includes a heave mechanism, a slewing mechanism, a boarding platform, a pitching mechanism, a telescopic mechanism, and a pier body. An active disturbance rejection control algorithm is designed for the slewing mechanism, the pitching mechanism, and the telescopic mechanism to coordinate their movements. While ensuring that the angle between the pier body and the horizontal plane remains a safe angle, the front end of the pier moves to the desired position of the target ship's deck. However, this invention uses a method of fusing 2D lidar and laser sensors to obtain the relative motion information between the target ship's deck and the front end of the pier. The calculation is complex and cannot obtain accurate position information of the overlap point relative to the front end of the maritime gangway.

[0005] Furthermore, in the aforementioned invention, the system adjustment time required for the wave compensation control to bring the front end of the gangway or pier to the desired position is uncertain, making it impossible to guarantee efficient connection between the offshore gangway and the offshore fixed or floating wind turbine platform. Summary of the Invention

[0006] To address the aforementioned problems in existing technologies, this invention proposes a preset time autonomous connection control system for marine gangways and its operating method, enabling efficient autonomous connection between marine gangways and fixed or floating offshore wind turbine platforms.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows:

[0008] A preset time autonomous connection control system for marine gangways, the marine gangway including a gangway base, a slewing mechanism, a transfer platform, a pitching mechanism, a gangway frame, a telescopic mechanism, and a connection point detection and positioning mechanism;

[0009] The joint point detection and positioning mechanism includes a three-axis gimbal and a binocular camera; the three-axis gimbal is installed below the front end of the offshore gangway to stabilize the attitude of the binocular camera so that the camera shooting direction is downward and perpendicular to the horizontal plane; the binocular camera is used to capture the identification symbols at the joint point of the offshore wind turbine platform and obtain binocular parallax information.

[0010] The state equation form of the dynamic model of the sea gangway is as follows:

[0011]

[0012] In the formula, X1 is the three-dimensional position vector of the front end of the sea gangway in the inertial coordinate system, and X2 is the three-dimensional velocity vector of the front end of the sea gangway in the inertial coordinate system. and denoted as the first derivatives of X1 and X2, respectively; M0(X1) is the nominal value of the 3×3 gangway inertia matrix; τ is the three-dimensional control input vector; Let M(X1) be the three-dimensional total disturbance vector consisting of parameter uncertainties and external disturbances, where M(X1) is the 3×3 dimensional gangway inertia matrix, and τ is the total disturbance vector. d Let X1 be the three-dimensional external disturbance vector caused by the waves, G(X1) be the three-dimensional gangway gravity vector, and C(X1,X2) be the 3×3 gangway Coriolis centripetal force matrix.

[0013] The preset-time autonomous connection control system includes an inertial measurement unit (IMU) and a main control computer. The IMU is installed on the maintenance vessel to measure its motion and attitude. The main control computer is also installed on the maintenance vessel and is configured with a connection point detection and positioning algorithm and a preset-time autonomous connection control algorithm. The connection point detection and positioning algorithm detects and identifies the markers at the connection point location. Based on the position information of the binocular camera and the disparity information of the center point of the markers detected by the connection point detection and positioning algorithm, the main control computer calculates the three-dimensional position of the connection point relative to the front end of the offshore gangway. Based on this, according to the three-dimensional position of the connection point relative to the front end of the offshore gangway, the motion and attitude of the maintenance vessel measured by the IMU, and the three-dimensional position of the front end of the offshore gangway in the inertial coordinate system, the desired three-dimensional position vector X for the connection between the front end of the offshore gangway and the offshore wind turbine platform is calculated through coordinate transformation. 1,d The preset time autonomous connection control algorithm is used to obtain the three-dimensional desired position vector X that makes the front end of the sea gangway follow the desired position vector. 1,dThe required three-dimensional control input vector τ drives the gangway rotation mechanism, pitch mechanism, and telescopic mechanism to move in a coordinated manner.

[0014] Furthermore, the preset time autonomous overlap control algorithm includes the following steps:

[0015] S1. Design the preset time function of the preset time extension state observer.

[0016] The preset time function for the preset time-expanded state observer is designed as follows:

[0017]

[0018] In the formula, sec is the trigonometric secant function, and T o This is the preset estimated time.

[0019] S2. Construct a preset time-dilation state observer.

[0020] To estimate the total disturbance W, a preset time-dilation state observer is constructed according to equations (1)-(2) as follows:

[0021]

[0022] In the formula, and These are the three-dimensional estimation vectors of X1, X2, and W respectively for the preset time-dilation state observer; The error vector for estimating the three-dimensional position of the front end of the sea gangway in the inertial coordinate system; β i and K i The matrix represents a 3×3 positive definite diagonal design parameter matrix, i = 1, 2, 3; Δ is a 3×3 positive definite diagonal constant matrix, where each diagonal element is greater than the 2-norm of the total perturbation W; κ is a piecewise time function, which is defined when t ∈ [0, T]. o When t∈[T], κ=0, and when t∈[T] o When , +∞), κ=1. The state estimation error of the preset time-dilation state observer is within the preset estimation time T. o It converges to zero.

[0023] S3. Design a preset time function for preset time autonomous overlap control.

[0024] The preset time function for the preset time autonomous overlap control is designed as follows:

[0025]

[0026] In the formula, T s T is the preset adjustment time. s >T o .

[0027] S4. Design a preset time-based autonomous three-dimensional control input vector.

[0028] First, the intermediate control vector for X2 is designed as follows:

[0029]

[0030] In the formula, γ1 and μ1 are both 3×3 positive definite diagonal design parameter matrices; Z1=X1-X 1,d This is the three-dimensional position error vector between the front end of the sea gangway and its desired position.

[0031] Then, a new error vector is defined as follows:

[0032] Z2=X2-α (6)

[0033] Based on equations (3) to (6), the preset time autonomous overlapping three-dimensional control input vector is designed as follows:

[0034]

[0035] In the formula, γ2 and μ2 are both 3×3 positive definite diagonal design parameter matrices. The preset time autonomously connects the three-dimensional control input vector to compensate for the motion and total disturbance of the maintenance vessel caused by waves, ensuring that the positional error between the front end of the offshore gangway and its desired position is within the preset adjustment time T. s It converges to zero.

[0036] Furthermore, the gangway base is installed on the port deck near the maintenance vessel;

[0037] The slewing mechanism is located above the gangway base and is used to drive the transfer platform and gangway frame to rotate.

[0038] The transfer platform is fixedly connected to the rotary mechanism and is used to carry personnel and materials;

[0039] The pitching mechanism is hinged to the transfer platform and the slewing mechanism, and is used to drive the gangway ladder frame to pitch.

[0040] The gangway ladder frame includes a fixed ladder frame, a telescopic ladder frame, and an inclined ladder;

[0041] The fixed ladder is hinged to the transfer platform;

[0042] The telescopic mechanism is located at the connection between the fixed ladder frame and the telescopic ladder frame, and is used to drive the telescopic ladder frame to telescopically move along the fixed ladder frame.

[0043] A method for operating a marine gangway preset-time autonomous connection control system includes the following steps:

[0044] A. Before autonomous docking, the maintenance vessel approaches the offshore wind turbine platform and activates its dynamic positioning system. At this time, the maintenance vessel maintains a safe working distance from the offshore wind turbine platform. The staff then manipulates the front end of the offshore gangway to move to a suitable initial position above the offshore wind turbine platform.

[0045] B. Set the preset adjustment time T s and overlap time T f,d The staff initiated the autonomous connection control command, and the binocular cameras began to operate. Based on the binocular camera's position information and the parallax information of the center point of the marker detected by the connection point detection and positioning algorithm, the main control computer output the required three-dimensional control input vector through the preset time autonomous connection control algorithm. This ensures that the front end of the sea gangway adjusts within a preset time T. s The internal position follows the Shanghai wind turbine platform's connection point at a height h above the initial position. f Position, and maintain that position for a period of time T f .

[0046] C. Based on the overlap time T f,d The performance requirements of the offshore gangway, the three-dimensional position vector of the offshore gangway's front end in the inertial coordinate system, and the three-dimensional position of the lap point relative to the offshore gangway's front end are determined by the main control computer, which plans the height h of the offshore gangway's front end from the lap point above the floating offshore wind turbine platform. f Position moved to the desired height h above the overlap point d The desired three-dimensional position vector is obtained, and the required three-dimensional control input vector is output; the front end of the offshore gangway will be at a height h above the joint point of the floating offshore wind turbine platform. f The position moves smoothly to the desired height h above the overlap point. d The position, and always follows the desired height h above the overlap point. d Position, keep the relative position of the front end of the sea ladder and the joint point unchanged.

[0047] D. The inclined ladder at the front of the sea gangway is lowered and automatically assembled.

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] 1. This invention uses a binocular camera, eliminating the need for multi-sensor fusion, and directly acquires accurate overlap point location information, making it simple and easy to implement. The proposed preset time autonomous overlap control method can pre-set the system adjustment time, and through the coordinated movement of the driving rotation mechanism, pitch mechanism and telescopic mechanism, efficiently compensate for the movement of the maintenance vessel caused by waves, so that the front end of the offshore gangway can follow the desired position of the overlap point in a timely and accurate manner, and overlap with the offshore wind turbine platform within the set overlap time, thereby ensuring the efficient autonomous overlap of the offshore gangway with the offshore fixed or floating wind turbine platform and improving the overlap efficiency.

[0050] 2. The present invention features a non-contact connection between the front end of the offshore gangway and the connection point of the offshore wind turbine platform. There are no special requirements for the connection point, and the connection can be made without contacting the offshore wind turbine platform. There is no need to build a landing device, which reduces the maintenance and manufacturing costs of the gangway. In case of emergencies, the gangway frame can be quickly raised to detach from the connection turntable, which improves the safety of the connection.

[0051] 3. In summary, this invention utilizes a binocular camera to obtain accurate position information of the overlap point relative to the front end of the offshore gangway in real time. Based on this, the gangway's rotation mechanism, pitch mechanism, and telescopic mechanism are driven to move in coordination through preset time autonomous overlap control. This actively, quickly, and accurately compensates for the disturbance to the position of the front end of the offshore gangway caused by the movement of the maintenance vessel. This allows the front end of the offshore gangway to follow the desired position above the overlap point of the fixed or floating offshore wind turbine platform in a timely manner, and to quickly and accurately overlap with the overlap point of the offshore wind turbine platform within the preset overlap time, thus achieving efficient autonomous overlap between the offshore gangway and the fixed or floating offshore wind turbine platform. Attached Figure Description

[0052] Figure 1 This is a schematic diagram of a ship's gangway structure at sea.

[0053] Figure 2 A schematic diagram of the autonomous assembly of a sea gangway;

[0054] Figure 3 A schematic diagram illustrating the autonomous assembly of a sea gangway.

[0055] Figure 4 This is a schematic diagram of the autonomous connection control principle for a preset time.

[0056] In the diagram: 1. Gangway base; 2. Rotation mechanism; 3. Transfer platform; 4. Pitching mechanism; 5. Fixed ladder frame; 6. Telescopic mechanism; 7. Telescopic ladder frame; 8. Inclined ladder; 9. Overlap point detection and positioning mechanism; 10. Offshore wind turbine platform; 11. Overlap point; 12. Front end of offshore gangway; 13. Maintenance vessel. Detailed Implementation

[0057] The invention will now be further described with reference to the accompanying drawings. Figure 1-4 As shown, a preset time autonomous connection control system for a marine gangway is disclosed. The marine gangway includes a gangway base 1, a slewing mechanism 2, a transfer platform 3, a pitching mechanism 4, a gangway frame, a telescopic mechanism 6, and a connection point detection and positioning mechanism 9.

[0058] The overlap point detection and positioning mechanism 9 includes a three-axis gimbal and a binocular camera; the three-axis gimbal is installed below the front end 12 of the offshore gangway to stabilize the attitude of the binocular camera so that the camera shooting direction is downward and perpendicular to the horizontal plane; the binocular camera is used to capture the identification symbols at the overlap point of the offshore wind turbine platform 10 and obtain binocular parallax information.

[0059] The state equation form of the dynamic model of the sea gangway is as follows:

[0060]

[0061] In the formula, X1 is the three-dimensional position vector of the front end 12 of the sea gangway in the inertial coordinate system, and X2 is the three-dimensional velocity vector of the front end 12 of the sea gangway in the inertial coordinate system. and denoted as the first derivatives of X1 and X2, respectively; M0(X1) is the nominal value of the 3×3 gangway inertia matrix; τ is the three-dimensional control input vector; Let M(X1) be the three-dimensional total disturbance vector consisting of parameter uncertainties and external disturbances, where M(X1) is the 3×3 dimensional gangway inertia matrix, and τ is the total disturbance vector. d Let X1 be the three-dimensional external disturbance vector caused by the waves, G(X1) be the three-dimensional gangway gravity vector, and C(X1,X2) be the 3×3 gangway Coriolis centripetal force matrix.

[0062] The preset-time autonomous connection control system includes an inertial measurement unit (IMU) and a main control computer. The IMU is installed on the maintenance vessel 13 and is used to measure the motion and attitude of the maintenance vessel 13. The main control computer is installed on the maintenance vessel 13 and is configured with a connection point detection and positioning algorithm and a preset-time autonomous connection control algorithm. The connection point detection and positioning algorithm is used to detect and identify the markers at the connection point location. Based on the position information of the binocular camera and the disparity information of the center point of the markers detected by the connection point detection and positioning algorithm, the main control computer calculates the three-dimensional position of the connection point 11 relative to the front end 12 of the offshore gangway. Based on this, according to the three-dimensional position of the connection point 11 relative to the front end 12 of the offshore gangway, the motion and attitude of the maintenance vessel 13 measured by the IMU, and the three-dimensional position of the front end 12 of the offshore gangway in the inertial coordinate system, the three-dimensional expected position vector X of the connection between the front end 12 of the offshore gangway and the offshore wind turbine platform 10 is calculated through coordinate transformation. 1,d The preset time autonomous connection control algorithm is used to obtain the desired three-dimensional position vector X for the front end 12 of the sea gangway. 1,d The required three-dimensional control input vector τ drives the gangway rotation mechanism, pitch mechanism, and telescopic mechanism to move in a coordinated manner.

[0063] Furthermore, the preset time autonomous overlap control algorithm includes the following steps:

[0064] S1. Design the preset time function of the preset time extension state observer.

[0065] The preset time function for the preset time-expanded state observer is designed as follows:

[0066]

[0067] In the formula, sec is the trigonometric secant function, and T o This is the preset estimated time.

[0068] S2. Construct a preset time-dilation state observer.

[0069] To estimate the total disturbance W, a preset time-dilation state observer is constructed according to equations (1)-(2) as follows:

[0070]

[0071] In the formula, and These are the three-dimensional estimation vectors of X1, X2, and W respectively for the preset time-dilation state observer; The error vector for estimating the three-dimensional position of the front end 12 of the sea gangway in the inertial coordinate system; β i and K i The matrix represents a 3×3 positive definite diagonal design parameter matrix, i = 1, 2, 3; Δ is a 3×3 positive definite diagonal constant matrix, where each diagonal element is greater than the 2-norm of the total perturbation W; κ is a piecewise time function, which is defined when t ∈ [0, T]. o When t∈[T], κ=0, and when t∈[T] o When , +∞), κ=1. The state estimation error of the preset time-dilation state observer is within the preset estimation time T. o It converges to zero.

[0072] S3. Design a preset time function for preset time autonomous overlap control.

[0073] The preset time function for the preset time autonomous overlap control is designed as follows:

[0074]

[0075] In the formula, T s T is the preset adjustment time. s >T o .

[0076] S4. Design a preset time-based autonomous three-dimensional control input vector.

[0077] First, the intermediate control vector for X2 is designed as follows:

[0078]

[0079] In the formula, γ1 and μ1 are both 3×3 positive definite diagonal design parameter matrices; Z1=X1-X 1,d This is the three-dimensional position error vector between the front end 12 of the sea gangway and its desired position.

[0080] Then, a new error vector is defined as follows:

[0081] Z2=X2-α (6)

[0082] Based on equations (3) to (6), the preset time autonomous overlapping three-dimensional control input vector is designed as follows:

[0083]

[0084] In the formula, γ2 and μ2 are both 3×3 positive definite diagonal design parameter matrices. The preset time autonomously connects the three-dimensional control input vector to compensate for the motion and total disturbance of the maintenance vessel 13 caused by waves, ensuring that the positional error between the front end 12 of the offshore gangway and its desired position is within the preset adjustment time T. s It converges to zero.

[0085] Furthermore, the gangway base 1 is installed on the port deck near the maintenance vessel 13;

[0086] The slewing mechanism 2 is located above the gangway base 1 and is used to drive the transfer platform 3 and the gangway frame to rotate.

[0087] The transfer platform 3 is fixedly connected to the rotary mechanism 2 and is used to carry personnel and materials;

[0088] The pitching mechanism 4 is hinged to the transfer platform 3 and the slewing mechanism 2, and is used to drive the gangway ladder frame to pitch.

[0089] The gangway ladder frame includes a fixed ladder frame 5, a telescopic ladder frame 7, and an inclined ladder 8;

[0090] The fixed ladder 5 is hinged to the transfer platform 3;

[0091] The telescopic mechanism 6 is located at the connection between the fixed ladder frame 5 and the telescopic ladder frame 7, and is used to drive the telescopic ladder frame 7 to telescopically move along the fixed ladder frame 5.

[0092] A method for operating a marine gangway preset-time autonomous connection control system includes the following steps:

[0093] A. Before autonomous docking, the maintenance vessel 13 approaches the offshore wind turbine platform 10 and activates the dynamic positioning system of the maintenance vessel 13. At this time, the maintenance vessel 13 maintains a safe working distance from the offshore wind turbine platform 10. The staff manipulates the front end 12 of the offshore gangway to move to a suitable initial position above the offshore wind turbine platform 10.

[0094] B. Set the preset adjustment time T s and overlap time T f,dThe staff initiated the autonomous connection control command, and the binocular camera began to work. Based on the binocular camera's position information and the parallax information of the center point of the marker detected by the connection point detection and positioning algorithm, the main control computer output the required three-dimensional control input vector through the preset time autonomous connection control algorithm, so that the front end 12 of the sea gangway is adjusted within the preset time T. s From its initial position, it follows the Shanghai wind turbine platform 10 above the joint point 11 at a height h. f Position, and maintain that position for a period of time T f .

[0095] C. Based on the overlap time T f,d The performance requirements of the offshore gangway, the three-dimensional position vector of the offshore gangway front end 12 in the inertial coordinate system, and the three-dimensional position of the overlap point 11 relative to the offshore gangway front end 12, the main control computer plans the height h of the offshore gangway front end 12 above the overlap point 11 of the floating offshore wind turbine platform 10. f Position moved to the desired height h above the overlap point 11 d The desired three-dimensional position vector is obtained, and the required three-dimensional control input vector is output; the front end 12 of the offshore gangway will be at a height h above the joint point 11 of the floating offshore wind turbine platform 10. f The position moves smoothly to the desired height h above the overlap point 11. d The position, and always follows the desired height h above the overlap point 11. d Position, keep the relative position of the front end 12 of the sea gangway and the joint point 11 unchanged.

[0096] D. The inclined ladder 8 is lowered down from the front end 12 of the sea gangway and automatically assembled.

[0097] This invention is not limited to this embodiment. Any equivalent concept or modification within the technical scope disclosed in this invention shall be included within the protection scope of this invention.

Claims

1. A preset-time autonomous connection control system for marine gangways, characterized in that: The sea gangway includes a gangway base (1), a slewing mechanism (2), a transfer platform (3), a pitching mechanism (4), a gangway frame, a telescopic mechanism (6), and a joint point detection and positioning mechanism (9); The overlap point detection and positioning mechanism (9) includes a three-axis gimbal and a binocular camera; the three-axis gimbal is installed below the front end (12) of the offshore gangway to stabilize the attitude of the binocular camera so that the camera shooting direction is downward and perpendicular to the horizontal plane; the binocular camera is used to capture the identification symbols at the overlap point of the offshore wind turbine platform (10) and obtain binocular parallax information. The state equation form of the dynamic model of the sea gangway is as follows: In the formula, X1 is the three-dimensional position vector of the front end (12) of the sea gangway in the inertial coordinate system, and X2 is the three-dimensional velocity vector of the front end (12) of the sea gangway in the inertial coordinate system. and denoted as the first derivatives of X1 and X2, respectively; M0(X1) is the nominal value of the 3×3 gangway inertia matrix; τ is the three-dimensional control input vector; Let M(X1) be the three-dimensional total disturbance vector consisting of parameter uncertainties and external disturbances, where M(X1) is the 3×3 dimensional gangway inertia matrix, and τ is the total disturbance vector. d Let G(X1) be the three-dimensional external disturbance vector caused by waves, G(X1) be the three-dimensional gangway gravity vector, and C(X1,X2) be the 3×3 gangway Coriolis centripetal force matrix. The preset time autonomous connection control system includes an inertial measurement unit (IMU) and a main control computer. The IMU is installed on the maintenance vessel (13) and is used to measure the motion posture of the maintenance vessel (13). The main control computer is installed on the maintenance vessel (13) and is configured with a connection point detection and positioning algorithm and a preset time autonomous connection control algorithm. The connection point detection and positioning algorithm is used to detect and identify the symbols at the connection point. The main control computer calculates the three-dimensional position of the connection point (11) relative to the front end (12) of the offshore gangway based on the position information of the binocular camera and the disparity information of the center point of the symbol detected by the connection point detection and positioning algorithm. Based on this, according to the three-dimensional position of the connection point (11) relative to the front end (12) of the offshore gangway, the motion posture of the maintenance vessel (13) measured by the IMU, and the three-dimensional position of the front end (12) of the offshore gangway in the inertial coordinate system, the three-dimensional expected position vector X of the connection between the front end (12) of the offshore gangway and the offshore wind turbine platform (10) is calculated by coordinate transformation. 1,d The preset time autonomous connection control algorithm is used to obtain the desired three-dimensional position vector X so that the front end (12) of the sea gangway follows the desired position vector X. 1,d The required three-dimensional control input vector τ drives the gangway rotation mechanism, pitch mechanism, and telescopic mechanism to move in coordination.

2. The marine gangway preset time autonomous connection control system according to claim 1, characterized in that: The preset time-based autonomous overlap control algorithm includes the following steps: S1. Design the preset time function of the preset time extension state observer. The preset time function for the preset time-expanded state observer is designed as follows: In the formula, sec is the trigonometric secant function, and T o Preset estimated time; S2. Construct a preset time-dilation state observer. To estimate the total disturbance W, a preset time-dilation state observer is constructed according to equations (1)-(2) as follows: In the formula, and These are the three-dimensional estimation vectors of X1, X2, and W respectively for the preset time-dilation state observer; The error vector for estimating the three-dimensional position of the front end (12) of the sea gangway in the inertial coordinate system; β i and K i The design parameter matrix is ​​a 3×3 positive definite diagonal matrix, i = 1, 2, 3; Δ is a 3×3 positive definite diagonal constant matrix, where each diagonal element is greater than the 2-norm of the total perturbation W; κ is a piecewise time function, which is defined when t∈[0,T]. o When t∈[T], κ=0, and when t∈[T] o When , +∞), κ=1; The state estimation error of the preset time-dilation state observer is within the preset estimation time T. o Converging inward to zero; S3. Design a preset time function for preset time autonomous overlap control. The preset time function for the preset time autonomous overlap control is designed as follows: In the formula, T s T is the preset adjustment time. s >T o ; S4. Design a preset time-based autonomous three-dimensional control input vector. First, the intermediate control vector for X2 is designed as follows: In the formula, γ1 and μ1 are both 3×3 positive definite diagonal design parameter matrices; Z1=X1-X 1,d The three-dimensional position error vector between the front end (12) of the sea gangway and its desired position; Then, a new error vector is defined as follows: Z2=X2-α (6) Based on equations (3) to (6), the preset time autonomous overlapping three-dimensional control input vector is designed as follows: In the formula, γ2 and μ2 are both 3×3 positive definite diagonal design parameter matrices; the preset time autonomously connects the three-dimensional control input vector to compensate for the motion and total disturbance of the maintenance vessel (13) caused by waves, ensuring that the position error between the front end of the offshore gangway (12) and its desired position is within the preset adjustment time T. s It converges to zero.

3. The marine gangway preset time autonomous connection control system according to claim 1, characterized in that: The gangway base (1) is installed on the port deck near the maintenance vessel (13); The slewing mechanism (2) is located above the gangway base (1) and is used to drive the transfer platform (3) and the gangway frame to rotate. The transfer platform (3) is fixedly connected to the rotary mechanism (2) and is used to carry personnel and materials; The pitching mechanism (4) is hinged to the transfer platform (3) and the slewing mechanism (2) and is used to drive the gangway ladder frame to pitch. The gangway ladder frame includes a fixed ladder frame (5), a telescopic ladder frame (7), and an inclined ladder (8); The fixed ladder (5) is hinged to the transfer platform (3); The telescopic mechanism (6) is located at the connection between the fixed ladder frame (5) and the telescopic ladder frame (7), and is used to drive the telescopic ladder frame (7) to telescopically move along the fixed ladder frame (5).

4. A method for operating a marine gangway preset time autonomous connection control system as described in any one of claims 1-3, characterized in that: Includes the following steps: A. Before autonomous docking, the maintenance vessel (13) approaches the offshore wind turbine platform (10) and activates the dynamic positioning system of the maintenance vessel (13). At this time, the maintenance vessel (13) maintains a safe working distance from the offshore wind turbine platform (10). The staff manipulates the front end (12) of the offshore gangway to move to a suitable initial position above the offshore wind turbine platform (10). B. Set the preset adjustment time T s and overlap time T f,d The staff initiated the autonomous connection control command, and the binocular camera started working. Based on the binocular camera's position information and the parallax information of the center point of the indicator detected by the connection point detection and positioning algorithm, the main control computer output the required three-dimensional control input vector through the preset time autonomous connection control algorithm, so that the front end (12) of the sea gangway is adjusted within the preset time T. s From its initial position, the inner part follows the Shanghai wind turbine platform (10) above the joint point (11) at a height h. f Position, and maintain that position for a period of time T f ; C. Based on the overlap time T f,d The performance requirements of the offshore gangway, the three-dimensional position vector of the offshore gangway front end (12) in the inertial coordinate system and the three-dimensional position of the overlap point (11) relative to the offshore gangway front end (12), the main control computer plans the height h of the offshore gangway front end (12) above the overlap point (11) of the floating offshore wind turbine platform (10). f The position moves to the desired height h above the overlap point (11). d The three-dimensional desired position vector of the location is obtained, and the required three-dimensional control input vector is output; the front end of the offshore gangway (12) will be at a height h above the joint point (11) of the floating offshore wind turbine platform (10). f The position moves smoothly to the desired height h above the overlap point (11). d The position, and always follows the desired height h above the overlap point (11). d Position, keep the relative position of the front end (12) of the sea gangway (11) unchanged; D. The inclined ladder (8) is lowered from the front end (12) of the sea gangway and automatically assembled.

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