Hybrid heave compensation system and method

Abstract

The invention relates to the technical field of hybrid heave compensation systems, and provides a hybrid heave compensation system and method, which have the advantages that the control logic is simple, an umbilical cable winch can realize quick response, active compensation and passive compensation combined action, the compensation precision is improved, and the power consumption is reduced. Comprising an active heave compensation device, a passive heave compensation device and a control system used for controlling the active heave compensation device and the passive heave compensation device, and further comprises a cable ROV, an A-shaped frame crane and a cable, the active heave compensation device comprises a winch and a vertical acceleration sensor, and the passive heave compensation device comprises a pulley block. And the cable sequentially bypasses the winch, the pulley block and the A-shaped frame crane and then is connected with the cable ROV.

Description

Technical Field

[0001] The present invention relates to the technical field of hybrid heave compensation systems, and in particular to a hybrid heave compensation system. Background Art

[0002] With my country's exploration and development of deep-sea areas, heavy-load and long-travel underwater robots are used in deep-sea operations. Under high sea conditions, affected by ship movement (especially heave and pitch), waves, currents, etc., the cabled underwater robot as a load will experience significant heave and sink during deployment and recovery and in-water or underwater operations due to the movement of the ship, which directly affects the accuracy of the underwater robot's depth determination operation and the detection accuracy of the detection equipment.

[0003] At present, the commonly used heave compensation devices are mainly: passive heave compensation device and active heave compensation device. Passive heave compensation device is widely used in offshore equipment heave compensation due to its mature technology, simple maintenance and low cost. However, its technical parameters are set according to work experience and cannot match the complex and changeable offshore environment, resulting in low compensation accuracy and low universality. Active heave compensation device uses MRU to measure the heave, pitch and roll motion of the ship, and controls the winch to compensate for the heave motion of the ship. Due to its high compensation accuracy, fast response speed and high safety, it is suitable for motion compensation of offshore equipment with high compensation accuracy requirements. However, since active compensation achieves rapid response of motion through control technology, it has high requirements for equipment response capability, drive capability, control technology, etc., so its development is not yet mature. Summary of the invention

[0004] One of the purposes of the present invention is to provide a hybrid heave compensation system with simple control logic, rapid response of the umbilical winch, and the combined effect of active compensation and passive compensation to improve the compensation accuracy.

[0005] The technical solution of the present invention is as follows: A hybrid heave compensation system comprises an active heave compensation device, a passive heave compensation device and a control system for controlling the active heave compensation device and the passive heave compensation device, comprising a cable ROV, an A-frame crane and a cable, wherein the active heave compensation device comprises a winch and a vertical acceleration sensor, and the passive heave compensation device comprises a pulley block, and the cable is connected to the cable ROV after passing through the winch, the pulley block and the A-frame crane in sequence.

[0006] Furthermore, the passive heave compensation device includes a frame, a compensation cylinder, an accumulator and a guide column, the pulley block includes a fixed pulley and a movable pulley, the fixed pulley is rotatably connected to the top of the frame, the movable pulley is rotatably connected to the bottom of the fixed pulley, and the rotating shaft of the movable pulley is slidably connected to the guide column through a roller, and the frame is also fixedly connected to a compensation cylinder for driving the movable pulley to move up and down along the guide column; The sensor assembly comprises a pin stress sensor for monitoring the cable tension and a displacement sensor for compensating the oil cylinder displacement monitoring.

[0007] Furthermore, the passive heave compensation device includes an accumulator and a pressure sensor for monitoring the accumulator pressure, and the accumulator is connected to the compensation cylinder.

[0008] Another object of the present invention is to provide a hybrid heave compensation method, the steps of which are as follows: S100: The control system determines the working depth of the cabled ROV; S200: When the tethered ROV is located on the ship deck through the splash zone to 20-40 meters below the sea surface, the hybrid working mode is used; When the tethered ROV is 40 meters below the sea surface and continues to be deployed to the seabed until it touches the bottom, the passive working mode is used; When the tethered ROV is operating underwater, the active compensation mode is used.

[0009] Furthermore, the active compensation mode in step S200 includes: S211: The vertical acceleration sensor installed at the stern measures the vertical acceleration of the ship; S212: The control system obtains the acceleration signal of the vertical acceleration sensor and performs digital processing and filtering; S213: performing a second integration on the filtered acceleration signal to obtain a displacement signal; S213: The control system drives the winch to quickly retract and release the cable according to the established control strategy, thereby achieving heave compensation.

[0010] Furthermore, the passive working mode in step S200 includes: S221: adopt multi-stroke constant tension compensation mode, divide it into multiple strokes according to the deployment water depth, and set the pressure value and cable tension value under different strokes; S222: When the ship is affected by waves and moves upward, the cable tension increases, the compensation cylinder shortens, and the movable pulley moves toward the fixed pulley along the guide column under the action of the cylinder. The cable wrapped around the pulley block is released, slowing down the ascent of the cabled ROV. When the ship is affected by waves and moves downward, the cable force decreases, the compensation cylinder extends, and the fixed pulley moves away from the fixed pulley along the guide column under the action of the cylinder. The cable at the end of the cabled ROV is wound in, slowing down the descent of the cabled ROV.

[0011] Furthermore, the hybrid working mode in step S200 includes: S231: The active compensation mode and the passive working mode operate simultaneously.

[0012] The working principle and beneficial effects of the present invention are: The present invention includes an active compensation (winch) device and a passive heave compensation device. The active heave compensation device collects the vertical acceleration of the ship through a vertical acceleration sensor installed at the stern of the ship, and can calculate the heave amount of the ship through secondary integration. The control strategy is used to control the drive motor to achieve the retraction and release of the cable, thereby achieving heave compensation for the ship's movement; the passive heave compensation device achieves single-stroke constant tension heave compensation through the extension and retraction of the hydraulic cylinder through multi-stroke air pressure regulation; when the two work together, high-precision heave compensation can be achieved, and when the two are used separately, different deployment and recovery scenarios can be applied.

[0013] The control system of the hybrid heave compensation has a simple control logic, the cable winch can achieve rapid response, and the active compensation and passive compensation work together to improve the compensation accuracy; the system can meet the deployment and recovery requirements of different water depths; the system adopts a vertical structure, and the fixed pulley is installed on the top to ensure that the cable output angle remains unchanged, effectively reducing the cable variable angle retraction and extension, and improving the cable life. At the same time, the structure is simple and compact, the cost is low, and it is easy to maintain. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0015] Figure 1 is a logic diagram of active heave compensation in this embodiment; Figure 2 is a schematic diagram of a dynamic heave compensation device and a passive heave compensation device in this embodiment; Figure 3 Schematic diagram of the structure of the passive heave compensation device in this embodiment.

[0016] In the figure: 1. Cabled ROV; 2. Cable; 3. A-frame crane; 4. Passive heave compensation device; 5. Pin stress sensor; 6. Winch; 7. Vertical acceleration sensor; 8. Ship; 9. Base; 12. Accumulator; 13. Gas cylinder; 15. Displacement sensor; 16. Pressure sensor; 17. Compensation cylinder; 18. Guide column; 19. Roller; 20. Frame; 21. Pump station; 22. Fixed pulley; 23. Moving pulley; 24. Support column. DETAILED DESCRIPTION

[0017] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0018] Embodiment 1

[0019] like Figure 2-3 As shown, a hybrid heave compensation system mainly includes an active heave compensation device, a passive heave compensation device 4 and a control system for controlling the active heave compensation device and the passive heave compensation device 4. The hardware of the control system is preferably a PLC controller. The rest also includes a cabled ROV 1, an A-frame crane 3 (fixedly connected to its own base 9 by bolts) and a cable 2. The active heave compensation device includes a winch 6 (fixedly connected to its own base 9 by bolts) and a vertical acceleration sensor. The passive heave compensation device 4 includes a pulley block. The cable 2 passes through the winch 6, the pulley block and the A-frame crane 3 in sequence and then connects to the cabled ROV 1.

[0020] Specifically, the passive heave compensation device 4 in this embodiment includes a frame 20 (fixedly connected to its own base 9 by bolts), a compensation cylinder 17, an accumulator 12 and a guide column 18, and the pulley block includes a fixed pulley 22 and a movable pulley 23, the fixed pulley 22 is rotatably connected to the top of the frame 20, the movable pulley 23 is rotatably connected to the lower part of the fixed pulley 22, and the rotating shaft of the movable pulley 23 is rotatably connected to a mounting seat, and a roller 19 is provided on the mounting seat, and the roller 19 is slidably connected to the guide column 18, and the guide column 18 acts as a slide rail. The frame 20 is also fixedly connected to a compensation cylinder 17 for driving the movable pulley 23 to move up and down along the guide column 18, and the compensation cylinder 17 is fixed to the frame 20 through a support column 24, and a pump station 21 is provided on one side of the frame 20.

[0021] At the same time, it also includes a sensor component, which includes a pin stress sensor 5 for monitoring the tension of the cable 2 , a displacement sensor 15 for monitoring the displacement of the compensation cylinder 17 , and a pressure sensor 16 for monitoring the pressure of the accumulator 12 .

[0022] The passive heave compensation device 4 further comprises an accumulator 12 , which is connected to a compensation cylinder 17 and cooperates with each other to achieve heave compensation.

[0023] Embodiment 2

[0024] like Figure 1 As shown, a hybrid heave compensation method, the steps are as follows: S100: The control system determines the working depth of the cabled ROV 1; S200: When the cabled ROV 1 is located on the deck of the ship 8 through the splash zone to 20-40 meters below the sea surface (this depth is the ocean wave reference plane), the ship 8 is greatly affected by wind and waves, and the hybrid working mode is used; When the cabled ROV 1 is located 40 meters below the sea surface and continues to be deployed to the seabed until it touches the bottom, the heave and sinking movement of the ship 8 has little effect on the cabled robot, and the passive working mode is used, and the winch 6 follows; When the cabled ROV 1 is operating underwater, the heave and sinking movement of the ship 8 has little effect on the robot. To prevent the robot from dragging and damaging the cable when walking and operating, the cable tension value must be monitored at all times and the active compensation mode must be used.

[0025] In the active compensation mode in step S200, only the winch 6 is started and the compensation cylinder 17 is locked, which specifically includes: S211: The vertical acceleration sensor 7 installed at the stern measures the vertical acceleration of the ship 8; S212: The control system obtains the acceleration signal of the vertical acceleration sensor 7, and performs digital processing and filtering; S213: performing a second integration on the filtered acceleration signal to obtain a displacement signal; The acceleration signal expression is: ; Integrate the acceleration signal to get the velocity signal: ; Integrating the velocity signal gives the displacement signal: ; Among them, c 1 、c 2 is a constant term.

[0026] S213: The control system drives the winch 6 to quickly retract and release the cable 2 according to the formulated control strategy, thereby achieving heave compensation.

[0027] The passive working mode in step S200 includes: S221: adopt a multi-stroke constant tension compensation method, divide it into multiple strokes according to the laying water depth, set the pressure value and cable tension value under different strokes, the laying process load is the robot's own weight, buoyancy, and cable weight, and as the laying depth increases, the cable tension gradually increases. In order to compensate for the contraction of the compensation cylinder 17 and the release of the cable caused by the increase in the cable's own weight, a multi-stroke compensation scheme is adopted during the laying process; With every 500 meters or every 400 meters as a stroke, a single stroke releases a certain number of high-pressure gas cylinders 13 to maintain the cylinder position of the passive compensation device and the piston position of the accumulator 12 at the preset position, and sets the cable tension value accordingly. The movement of the ship 8 causes the tension of the cable 2 to change. When it exceeds the set constant tension threshold, the compensation cylinder 17 is extended and retracted, thereby achieving deep compensation. This method divides the single-stroke distance according to the target deployment water depth and the number of high-pressure gas cylinders used, and realizes single-stroke constant tension compensation by adjusting the pressure value of the high-pressure gas cylinder, which can efficiently and accurately meet the different water depth heave compensation and realize constant tension compensation.

[0028] S222: When the ship 8 is affected by the waves and moves upward, the tension of the cable 2 increases, the compensation cylinder 17 shortens, and the movable pulley 23 moves along the guide column 18 toward the fixed pulley 22 under the action of the cylinder, and the cable 2 wound on the pulley block is released, slowing down the ascent of the cabled ROV 1; When the ship 8 is affected by waves and moves downward, the force of the cable 2 decreases, the compensation cylinder 17 extends, and the fixed pulley 22 moves away from the fixed pulley 22 along the guide column 18 under the action of the cylinder. The cable 2 at the end of the cabled ROV1 is wound in, slowing down the descent of the cabled ROV1.

[0029] The hybrid working mode in step S200 includes: S231: The active compensation mode and the passive working mode operate simultaneously.

[0030] Initially, the heavy hydraulic cylinder and accumulator 12 piston of the passive compensation device are in preset positions. When the ship 8 rises, the cabled ROV1 has a large inertia, the cable tension increases, the load acting on the compensation cylinder 17 increases, the compensation cylinder 17 retracts and compresses the air to the accumulator 12, and the cable is released at the same time to achieve passive compensation; the acceleration sensor and the stress sensor transmit the monitored data to the winch 6 control unit, and the control unit sends instructions to control the winch 6 to retract and release the cable according to the set control strategy. The two systems work together to achieve heave compensation for the movement of the ship 8.

[0031] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A hybrid heave compensation system, comprising an active heave compensation device, a passive heave compensation device (4) and a control system for controlling the active heave compensation device and the passive heave compensation device (4), characterized in that: The invention comprises a cabled ROV (1), an A-frame crane (3) and a cable (2), wherein the active heave compensation device comprises a winch (6) and a vertical acceleration sensor, and the passive heave compensation device (4) comprises a pulley block, and the cable (2) is connected to the cabled ROV (1) after passing through the winch (6), the pulley block and the A-frame crane (3) in sequence; The passive heave compensation device (4) comprises a frame (20), a compensation cylinder (17), an accumulator (12) and a guide column (18); the pulley block comprises a fixed pulley (22) and a movable pulley (23); the fixed pulley (22) is rotatably connected to the top of the frame (20); the movable pulley (23) is rotatably connected to the bottom of the fixed pulley (22); and the rotating shaft of the movable pulley (23) is slidably connected to the guide column (18) via a roller (19); the frame (20) is also fixedly connected to a compensation cylinder (17) for driving the movable pulley (23) to move up and down along the guide column (18).

2. A hybrid heave compensation system according to claim 1, characterized in that: The sensor assembly comprises a pin stress sensor (5) for monitoring the tension of a cable (2) and a displacement sensor (15) for monitoring the displacement of a compensation cylinder (17).

3. A hybrid heave compensation system according to claim 2, characterized in that: The passive heave compensation device (4) comprises an accumulator (12) and a pressure sensor (16) for monitoring the pressure of the accumulator (12); the accumulator (12) is connected to a compensation cylinder (17).

4. A hybrid heave compensation method, characterized in that: The hybrid heave compensation system according to any one of claims 1 to 3 comprises the following steps: S100: The control system determines the working depth of the cabled ROV (1); S200: When the tethered ROV (1) is located on the deck of the vessel (8) through the splash zone to 20-40 meters below the sea surface, the hybrid working mode is used; When the tethered ROV (1) is located 40 meters below the sea surface and continues to be deployed toward the seabed until it touches the bottom, the passive working mode is used; When the tethered ROV (1) is operating underwater, the active compensation mode is used; The active compensation mode in step S200 includes: S211: A vertical acceleration sensor (7) installed at the stern measures the vertical acceleration of the ship (8); S212: The control system obtains the acceleration signal of the vertical acceleration sensor (7), and performs digital processing and filtering; S213: performing a second integration on the filtered acceleration signal to obtain a displacement signal; S213: The control system drives the winch (6) to quickly retract and release the cable (2) according to the formulated control strategy, thereby achieving heave compensation.

5. A hybrid heave compensation method according to claim 4, characterized in that: The passive working mode in step S200 includes: S221: adopt multi-stroke constant tension compensation mode, divide it into multiple strokes according to the deployment water depth, and set the pressure value and cable tension value under different strokes; S222: When the ship (8) is affected by the waves and moves upward, the tension of the cable (2) increases, the compensation cylinder (17) shortens, and the movable pulley (23) moves along the guide column (18) toward the fixed pulley (22) under the action of the cylinder, and the cable (2) wound on the pulley block is released, thereby slowing down the ascent of the cabled ROV (1); When the ship (8) is affected by waves and moves downward, the force of the cable (2) decreases, the compensation cylinder (17) stretches, and the fixed pulley (22) moves away from the fixed pulley (22) along the guide column (18) under the action of the cylinder, and the cable (2) at the end of the cabled ROV (1) is wound in, thereby slowing down the descent of the cabled ROV (1).

6. A hybrid heave compensation method according to claim 5, characterized in that: The hybrid working mode in step S200 includes: S231: The active compensation mode and the passive working mode operate simultaneously.

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