A mooring line positioning device, a ship power positioning system and a method of operation thereof

Abstract

The application discloses a kind of tensioning cable positioning device, ship power positioning system and its working method, it is related to ship positioning technical field, the device includes counterweight, it is connected with ship using flexible cable, and it can be fixed on seabed by gravity after artificial delivery;Sonar sounder is fixedly connected with the counterweight and can be isolated seawater, for continuously emitting underwater acoustic signal;Receiving module is fixedly arranged on the deck of ship, for receiving the underwater acoustic signal emitted by the sonar sounder;Data solving unit is communicatively connected with the receiving module, for collecting the underwater acoustic signal received by the receiving module, and measuring propagation time, calculating the straight-line distance from the receiving module to the sonar sounder, combined with seawater depth to solve ship coordinates and attitude angle.The tensioning cable positioning device, ship power positioning system and its working method provided by the application can eliminate the influence of steel cable deformation, simplify the structure, and adapt to complex marine environment.

Description

Technical Field

[0001] This invention relates to the field of ship positioning technology, and in particular to a ship dynamic positioning device and its working method. Background Technology

[0002] In dynamic positioning (DP) systems, tensioned cable positioning devices are commonly used for auxiliary positioning. These devices connect the ship to a seabed weight via a steel cable, measuring the cable's extension length and tilt angle to calculate the ship's relative position. Traditional dynamic positioning primarily relies on contact-based mechanical measurement methods. While this approach can achieve a certain level of accuracy under ideal conditions, it presents the following technical challenges in real-world marine environments, especially in deep-sea conditions with strong currents: First, in traditional tension cable positioning devices, the steel cable is susceptible to bending and displacement due to seawater flow. As water depth and flow velocity increase, the deviation between the actual spatial shape of the steel cable and the theoretical straight-line model increases significantly, leading to a large error between the measured and actual cable length. This, in turn, causes the positioning error to increase exponentially, severely affecting the positioning accuracy of the DP system.

[0003] Secondly, to correct for errors caused by cable deformation, traditional devices typically require an additional tension detection module to monitor cable tension changes and assist in data correction. However, this module has a complex structure, numerous components, and tension sensors are prone to failure. Furthermore, long-term use of the cable can lead to wear and even breakage, resulting in decreased system reliability and higher maintenance costs.

[0004] Furthermore, under extreme conditions such as strong water flow, the measurement error of traditional tension cable positioning devices is difficult to control effectively, and the positioning accuracy cannot meet the high stability requirements of deep-sea operations.

[0005] In summary, there is an urgent need for a technical solution that can eliminate the effects of steel cable deformation, simplify the structure, and adapt to complex marine environments. Summary of the Invention

[0006] The purpose of this invention is to provide a tension cable positioning device, a ship dynamic positioning system and its working method to solve the problems existing in the prior art, and to eliminate the influence of steel cable deformation, simplify the structure and adapt to complex marine environments.

[0007] To achieve the above objectives, the present invention provides the following solution: This invention provides a tensioning cable positioning device, including a counterweight, a sonar transmitter, a receiving module, and a data processing unit. The counterweight is connected to the ship via a flexible cable and can be fixed to the seabed by gravity after being manually deployed. The sonar transmitter is fixedly connected to the counterweight and can isolate the ship from seawater, for continuously emitting underwater acoustic signals. The receiving module is fixedly mounted on the ship's deck for receiving the underwater acoustic signals emitted by the sonar transmitter. The data processing unit is communicatively connected to the receiving module for collecting the underwater acoustic signals received by the receiving module, calculating the propagation time, calculating the straight-line distance from the receiving module to the sonar transmitter, and calculating the ship's coordinates and attitude angles in conjunction with the seawater depth.

[0008] In one embodiment, there are three receiving modules, which are rigidly fixed on the ship's deck and can form a fixed rigid triangle when connected in sequence.

[0009] In one embodiment, the counterweight has a sealed cavity, and the sonar transmitter is fixedly and sealed within the sealed cavity.

[0010] In one embodiment, the sonar transmitter includes a sealed housing and a generator body, the generator body being fixedly and sealed within the sealed housing, and one side of the sealed housing being fixedly snapped, riveted, or glued to the counterweight.

[0011] The present invention also provides a ship dynamic positioning system, including a power system, a thrust system, a control system, and the aforementioned tension cable positioning device; the power system is used to provide the required power to the thrust system, the control system, and the tension cable positioning device; the thrust system is used to drive the ship to move to a set coordinate position and maintain a set angle; the control system is able to receive the output results of the data calculation unit and control the thrust system accordingly.

[0012] The present invention also provides a working method based on a ship dynamic positioning system, comprising the following steps: A counterweight connected to a sonar transmitter is dropped to the seabed and fixed by its own weight. Determine the seawater depth, establish a three-dimensional coordinate system, and calculate and store the initial coordinates and initial attitude angles of the three receiving modules; During ship operations, the sonar transmitter continuously emits signals, and three receiving modules collect the signals in real time. The data processing unit calculates the real-time distance and resolves the real-time coordinates, attitude angles, and deflection angles of the three receiving modules. The positioning data is directly transmitted to the control system to complete the closed-loop positioning feedback. The thrust system receives commands from the control system and adjusts the ship's position and attitude angle.

[0013] In one embodiment, the locations of the three receiving modules are defined as points A, B, and C, respectively; a three-dimensional rectangular coordinate system with a fixed vertical Z-axis is established with the seabed sonar transmitter as the origin and the vertical depth of the seawater as H. Points A, B, and C are all located in the horizontal plane Z=H.

[0014] In one embodiment, the acoustic propagation speed of seawater is set to a fixed value v. The time taken for the underwater acoustic signal to propagate from the origin to points A, B, and C is measured as t1, t2, and t3, respectively. The spatial straight-line distance R from points A, B, and C to the sonar transmitter is then obtained. A R B and R C : R A = v t1 R B = v t2 R C = v t3.

[0015] In one embodiment, point A is taken as the ship's reference attitude point. Combining the three-dimensional spatial distance formula and the rigid triangle side length constraint, the initial coordinates of point A are calculated by solving a simultaneous equation: + + = + + = + + = The distance AB between point A and point B is = The distance BC between point B and point C = The distance AC between point A and point C = .

[0016] In one embodiment, the initial attitude angle θ = 0° is defined as the horizontal azimuth angle of the line connecting point A and the origin when the bow of the ship is vertically upward and the counterweight is located on the right side of the ship. After the ship shifted, underwater acoustic signals were reacquired, and the real-time distances from three points to the sonar transmitter were measured. Similarly, calculate the real-time coordinates of point A. ; The formula for calculating the real-time attitude angle α is: α= Ship attitude deflection angle Δθ = α - θ; The horizontal straight-line distance D from the ship to the origin = .

[0017] The present invention achieves the following technical effects compared to the prior art: This invention employs a sonar transmitter fixed to the seabed to emit underwater acoustic signals, which are received by a receiver module fixed to the ship's hull. Ship positioning is achieved based on these underwater acoustic signals, completely eliminating positioning errors caused by cable deformation due to water flow. Positioning accuracy remains unaffected even in deep water and strong currents. The ship dynamic positioning device consists only of a counterweight, sonar transmitter, receiver module, and calculation unit, with no complex mechanical parts or easily damaged components. It operates simply by dropping the counterweight into the water, making installation and operation simple and convenient. It does not rely on any external equipment such as GPS, compass, or attitude sensors; the entire device operates independently, exhibiting strong anti-interference capabilities and avoiding the impact of external equipment failures on positioning. Three receiver modules provide rigid three-point reception, forming a complete constraint and uniquely determining the ship's position in all 360° directions, completely resolving the symmetric ambiguity problem of two-point reception. It eliminates issues such as cable wear and tension sensor failure, resulting in a long equipment lifespan and significantly reduced maintenance workload.

[0018] This invention overcomes the industry pain point of traditional tensioning cables being greatly affected by water flow and depth, providing high-precision and high-stability positioning assurance for deep-sea oil and gas extraction, offshore wind power installation, deep-sea scientific research and other projects, significantly reducing the safety risks of deep-sea operations and improving operational efficiency; it realizes the technological innovation of ship DP positioning tensioning cables, replacing the traditional mechanical solution with a steel cable acoustic solution, promoting the industry towards intelligent and contactless development, and helping to upgrade my country's marine engineering equipment technology. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the initial positioning process of the tension cable positioning device in one or more embodiments of the present invention; Figure 2 This is a schematic diagram of the repositioning process of the tension cable positioning device in one or more embodiments of the present invention.

[0021] In the picture: 1-ship, 2-sonar transmitter. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] The purpose of this invention is to provide a tension cable positioning device, a ship dynamic positioning system and its working method to solve the problems existing in the prior art, and to eliminate the influence of steel cable deformation, simplify the structure and adapt to complex marine environments.

[0024] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] Example 1 Existing ship positioning (DP) systems are equipped with traditional tension cable devices that rely on steel cables to pull weights for positioning. They use mechanical mechanisms to measure the cable's extension length and tilt angle, and then calculate the ship's relative position based on the weight's position. This is a contact-based mechanical measurement method. In practical use, seawater currents cause the steel cable to bend and shift. The deeper the water and the higher the current velocity, the more significant the cable deformation. This leads to a large deviation between the actual and measured cable lengths, directly causing a geometric increase in positioning error. To solve this problem, this invention provides a tension cable positioning device, referencing... Figure 1 and Figure 2As shown, the system includes a counterweight, a sonar transmitter 2, a receiving module, and a data processing unit. The counterweight is made of a columnar, cuboid, or polygonal structure and can be made of stainless steel or other corrosion-resistant metals. The counterweight is connected to the ship 1 by a flexible cable, which, after being manually deployed, can be fixed to the seabed by gravity. The flexible cable can be made of steel cable, tow rope, or other rope structure. The sonar transmitter 2 is fixedly connected to the counterweight and is isolated from seawater, used for continuous transmission of underwater acoustic signals. The receiving module is fixedly mounted on the deck of the ship 1. The receiving module in this embodiment is used to receive underwater acoustic signals emitted by sonar transmitter 2. The three receiving modules are rigidly fixed on the deck of the ship 1, and the three receiving modules can form a fixed rigid triangle when connected in sequence. The locations of the three receiving modules are defined as points A, B and C, respectively. The data processing unit is communicatively connected to the receiving modules and is used to collect the underwater acoustic signals received by the receiving modules, measure the propagation time, calculate the straight-line distance from the receiving module to the sonar transmitter 2, and calculate the coordinates and attitude angle of the ship 1 in combination with the seawater depth. This invention employs acoustic signal positioning, assisting traditional tensioning cables to reduce measurement errors and fundamentally eliminating positioning errors caused by cable deformation and water flow. It achieves independent calculation of the position and attitude of the vessel 1 using only a sonar transmitter 2 embedded in a weight on the seabed and three receiving modules arranged in a triangle on the deck of the vessel 1, without relying on any external sensors. The triangular arrangement of the three receiving modules solves the quadrant ambiguity problem of two-point acoustic reception, uniquely determining the coordinates of the vessel 1 in all 360° directions, adapting to complex conditions of deep-sea currents and great depths. In cases of excessively strong currents, simply placing the weight on the seabed for fixation is sufficient for operation, reducing equipment failure rates and maintenance costs, and improving the stability and accuracy of the DP positioning system.

[0026] In one embodiment, the counterweight has a sealed cavity with an access port, which is sealed with a rubber plug. This allows the sonar transmitter 2 to be fixedly and sealed within the cavity, simplifying the overall structure. In another embodiment, the sonar transmitter 2 includes a sealed housing made of plastic and a generator body. The generator body is used to emit underwater acoustic signals and is fixedly and sealed within the sealed housing. One side of the sealed housing is fixedly snapped, riveted, or glued to the counterweight, allowing the sonar transmitter and counterweight to be arranged separately, resulting in a stronger acoustic signal and reducing the shielding effect of the counterweight on the underwater acoustic signal. The specific structure and principle of the sonar transmitter are not limited, as they are all mature technologies.

[0027] Example 2 This embodiment provides a dynamic positioning system for a ship 1, including the tension cable positioning device of Embodiment 1 above, as well as a power system, thrust system, and control system, which are mature existing technologies. The power system in this embodiment provides the necessary power to the thrust system, control system, and tension cable positioning device. The thrust system drives the ship 1 to move to a set coordinate position and maintain a set angle. The control system receives the output results of the data processing unit and controls the thrust system accordingly. Specifically, the power system provides power to the entire ship 1 and its dynamic positioning system, and is usually powered by the ship 1's power station, requiring redundancy and other special requirements. In large DP ships 1, closed-loop power grid technology is often used to improve power supply reliability and operating efficiency. The thruster system, as the actuator of the ship 1's dynamic positioning system, commonly uses electric motors or diesel engines to drive propellers to achieve thrust output. The main propulsion device (including its rudder system) can also serve as the thruster for the ship 1's dynamic positioning system. The dynamic positioning control system includes existing position reference sensors (such as GPS, acoustic beacons, etc.), environmental sensors (anemometers, motion sensors, current meters, etc.), and a DP controller (i.e., the system brain), which is responsible for data acquisition, filtering and estimation, thrust distribution, and control command output.

[0028] Example 3 This embodiment provides a working method based on the dynamic positioning system of a ship 1, including the following steps: like Figure 1 and Figure 2 In this embodiment, the locations of the three receiving modules are defined as points A, B, and C, respectively. A counterweight connected to sonar transmitter 2 is deployed to the seabed and fixed by its own weight, requiring no steel cable traction or tension detection; the device automatically powers on and initializes. The seawater depth H is measured, and a three-dimensional coordinate system is established. The origin O (0, 0, 0) is the sonar transmitter within the counterweight on the seabed, the vertical depth of the seawater is H (Z-axis fixed), the vertical direction is the Z-axis, and the two horizontal directions are the X and Y axes. A three-dimensional rectangular coordinate system is established, and the initial coordinates and initial attitude angles of the three receiving modules are calculated and stored, i.e., the initial coordinates of point A. With the initial attitude angle θ, the initial coordinates of point B With initial attitude angle Initial coordinates of point C With initial attitude angle During the operation of vessel 1, sonar transmitter 2 continuously transmits signals, and three receiving modules collect signals in real time. The data processing unit calculates the real-time distance and resolves the real-time coordinates, attitude angles, and deflection angles of the three receiving modules, namely, the real-time coordinates, attitude angle α, and deflection angle Δθ of point A, and the real-time coordinates, attitude angle α, and deflection angle Δθ of point B. Real-time coordinates of point C, real-time attitude angle α, and deflection angle Δ The positioning data is directly transmitted to the control system to complete the closed-loop positioning feedback; the thrust system receives commands from the control system and adjusts the position and attitude angle of the ship.

[0029] With the underwater sonar transmitter 2 as the origin and the vertical depth of the seawater as H, a three-dimensional rectangular coordinate system with a fixed vertical Z-axis is established. Points A, B, and C are all located in the horizontal plane Z=H.

[0030] In one embodiment, the acoustic propagation speed of seawater is set to a fixed value v, and the time taken for the underwater acoustic signal to propagate from the origin to points A, B, and C is measured as t1, t2, and t3, respectively. The spatial straight-line distance R from points A, B, and C to the sonar transmitter 2 is then obtained. A R B and R C : R A = v t1 R B = v t2 R C = v t3.

[0031] Taking point A as the reference attitude point of ship 1, and combining the three-dimensional spatial distance formula with the rigid triangle side length constraint, the initial coordinates of point A are calculated by solving the simultaneous equations: + + = + + = + + = The distance AB between point A and point B is = The distance BC between point B and point C = The distance AC between point A and point C = Define the initial attitude angle θ = 0°: the horizontal azimuth angle of the line connecting point A and the origin when the bow of ship 1 is vertically upward and the counterweight is located on the right side of ship 1; After the vessel 1 shifted, underwater acoustic signals were reacquired, and the real-time distances from three points to sonar transmitter 2 were measured. Similarly, calculate the real-time coordinates of point A. ; The formula for calculating the real-time attitude angle α is: α= Ship 1 attitude deflection angle Δθ=α-θ; The horizontal straight-line distance D from ship 1 to the origin = .

[0032] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A tension cable positioning device, characterized in that: include: The counterweight is connected to the ship by flexible cables and can be fixed to the seabed by gravity after being deployed by humans. A sonar transmitter, which is fixedly connected to the counterweight and can isolate seawater, is used to continuously emit underwater acoustic signals; The receiving module is fixedly installed on the deck of the ship and is used to receive underwater acoustic signals emitted by the sonar transmitter. as well as The data processing unit is communicatively connected to the receiving module and is used to collect underwater acoustic signals received by the receiving module, measure the propagation time, calculate the straight-line distance from the receiving module to the sonar transmitter, and calculate the ship's coordinates and attitude angles in combination with the seawater depth.

2. The tension cable positioning device according to claim 1, characterized in that: The receiving module is provided in three parts. The three receiving modules are rigidly fixed on the ship deck, and the three receiving modules can form a fixed rigid triangle when connected in sequence.

3. The tension cable positioning device according to claim 1, characterized in that: The counterweight has a sealed cavity, and the sonar transmitter is fixedly and sealed within the sealed cavity.

4. The tension cable positioning device according to claim 1, characterized in that: The sonar transmitter includes a sealed housing and a generator body. The generator body is fixedly and sealed inside the sealed housing. One side of the sealed housing is fixedly snapped, riveted, or glued to the counterweight.

5. A ship dynamic positioning system, characterized in that: The system includes a power system, a thrust system, a control system, and a tension cable positioning device as described in any one of claims 1 to 4; the power system is used to provide the required power to the thrust system, the control system, and the tension cable positioning device; the thrust system is used to drive the vessel to move to a set coordinate position and maintain a set angle; the control system is able to receive the output results of the data processing unit and control the thrust system accordingly.

6. A method for operating the ship dynamic positioning system according to claim 5, characterized in that: Includes the following steps: A counterweight connected to a sonar transmitter is dropped to the seabed and fixed by its own weight. Determine the seawater depth, establish a three-dimensional coordinate system, and calculate and store the initial coordinates and initial attitude angles of the three receiving modules; During ship operations, the sonar transmitter continuously emits signals, and three receiving modules collect the signals in real time. The data processing unit calculates the real-time distance and resolves the real-time coordinates, attitude angles, and deflection angles of the three receiving modules. The positioning data is directly transmitted to the control system to complete the closed-loop positioning feedback. The thrust system receives commands from the control system and adjusts the ship's position and attitude angle.

7. The working method according to claim 6, characterized in that: The locations of the three receiving modules are defined as points A, B, and C, respectively. A three-dimensional rectangular coordinate system with a fixed vertical Z-axis is established with the seabed sonar transmitter as the origin and the vertical depth of the seawater as H. Points A, B, and C are all located in the horizontal plane Z=H.

8. The working method according to claim 7, characterized in that: Assuming the acoustic propagation speed in seawater is a fixed value v, the time taken for the underwater acoustic signal to propagate from the origin to points A, B, and C is measured as t1, t2, and t3, respectively. The spatial straight-line distance R from points A, B, and C to the sonar transmitter is then obtained. A R B and R C : R A = v t1 R B = v t2 R C = v t3。 9. The working method according to claim 8, characterized in that: Using point A as the ship's reference attitude point, and combining the three-dimensional spatial distance formula with the rigid triangle side length constraint, the initial coordinates of point A are calculated by solving the simultaneous equations: + + = + + = + + = The distance AB between point A and point B is = The distance BC between point B and point C = The distance AC between point A and point C = .

10. The working method according to claim 9, characterized in that: Define the initial attitude angle θ=0°: the horizontal azimuth angle of the line connecting point A and the origin when the bow of the ship is vertically upward and the counterweight is located on the right side of the ship; After the ship shifted, underwater acoustic signals were reacquired, and the real-time distances from three points to the sonar transmitter were measured. Similarly, calculate the real-time coordinates of point A. ; The formula for calculating the real-time attitude angle α is: α= Ship attitude deflection angle Δθ = α - θ; The horizontal straight-line distance D from the ship to the origin = .

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