submarine

Abstract

A submersible according to one embodiment of the present disclosure is configured to: determine a first direction which is the direction in which the position of the cross-sectional center of a pipeline is seen from a first magnetic sensor, said determination made on the basis of the magnitude of magnetic force in the Y-direction and the magnitude of magnetic force in the Z-direction as measured by the first magnetic sensor; determine a second direction which is the direction in which the position of the cross-sectional center of the pipeline is seen from a second magnetic sensor, said determination made on the basis of the magnitude of magnetic force in the Y-direction and the magnitude of magnetic force in the Z-direction as measured by the second magnetic sensor; and calculate the position of the cross-sectional center of the pipeline on the basis of the determined first direction and second direction.

Description

Technical Field

[0001] This disclosure relates to submarines.

Background Art

[0002] The exact position of a pipeline laid on the seabed can be grasped using a camera or the like mounted on a submarine. However, when the pipeline is buried in the seabed, the exact position of the pipeline cannot be grasped without using a method other than a visual method. Patent Document 1 below discloses a submarine cable exploration system that detects the presence of a submarine cable by detecting a direct current magnetic field generated from a direct current flowing through the submarine cable.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] On the other hand, it is not easy for a pipeline to flow an electric current like a submarine cable, and it is difficult to grasp the exact position of the pipeline by applying the method described in Patent Document 1. Therefore, an object of the present disclosure is to provide a submarine that can grasp the exact position of a pipeline by a simple method even when the pipeline is buried in the seabed.

Means for Solving the Problems

[0005] A submersible according to one aspect of the present disclosure comprises a hull, a propulsion system that provides thrust to the hull, a first magnetic sensor attached to the hull capable of three-dimensional measurement of magnetic force, a second magnetic sensor attached to the hull at a different position from the first magnetic sensor and capable of three-dimensional measurement of magnetic force, and a control device that moves the hull along a magnetized pipeline while calculating the cross-sectional center position of the pipeline. The control device determines, when the hull is propelled along the X direction, the direction intersecting the X direction is the Y direction, and the direction intersecting the X and Y directions is the Z direction, a first direction which is the direction of the cross-sectional center position of the pipeline as seen from the first magnetic sensor, based on the magnitude of the magnetic force in the Y direction and the magnitude of the magnetic force in the Z direction measured by the first magnetic sensor, a second direction which is the direction of the cross-sectional center position of the pipeline as seen from the second magnetic sensor, based on the magnitude of the magnetic force in the Y direction and the magnitude of the magnetic force in the Z direction measured by the second magnetic sensor, and calculates the cross-sectional center position of the pipeline based on the determined first and second directions. [Effects of the Invention]

[0006] This configuration allows for the precise location of a pipeline to be determined in a simple manner, even if the pipeline is buried on the seabed. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a plan view of the submersible. [Figure 2] Figure 2 is a block diagram of the control system of a submarine. [Figure 3] Figure 3 illustrates the magnetic properties of the pipeline. [Figure 4] Figure 4 shows the magnetic force in a plane perpendicular to the pipeline. [Figure 5] Figure 5 is a flowchart of the pipeline cross-section center position calculation program. [Figure 6] Figure 6 shows the positional relationship between the submersible and the pipeline during the execution of the pipeline cross-section center position calculation program. [Figure 7] Figure 7 shows the movement of the submersible during the execution of the pipeline cross-section center position calculation program. [Figure 8] Figure 8 shows the magnitudes of the magnetic force in the Y and Z directions plotted on a coordinate plane. [Modes for carrying out the invention]

[0008] (Overall configuration of the submarine) The embodiments will now be described. First, the overall configuration of the submersible 100 will be explained. Figure 1 is a plan view of the submersible 100. Figure 2 is a block diagram of the control system of the submersible 100. In this embodiment, the submersible 100 moves along the pipeline 101 (see Figure 6) while calculating the cross-sectional center position of the pipeline 101 (the center position of the cross-section perpendicular to the longitudinal direction of the pipeline 101). In this embodiment, the submersible 100 collects position data of the pipeline 101 while moving. However, the submersible 100 may also perform non-contact inspections of the pipeline 101 while moving.

[0009] As shown in Figure 1, the submersible 100 comprises a hull 11, a propulsion system 12, a first magnetic sensor 13, a second magnetic sensor 14, and a control device 15 (see Figure 2). These components will be described in order below.

[0010] <hull> The hull 11 is equipped with various devices. In Figure 1, the right and left sides of the paper represent the front and rear of the hull 11, respectively; the top and bottom of the paper represent the left and right sides of the hull 11, respectively; and the foreground and background of the paper represent the top and bottom of the hull 11, respectively. The hull 11 propels itself forward.

[0011] <Propulsion System> The propulsion system 12 is a system that provides thrust to the hull 11. The propulsion system 12 can also adjust the attitude and direction of propulsion of the hull 11. The propulsion system 12 of this embodiment has a main thruster 21 that generates forward thrust, two vertical thrusters 22 that apply vertical force to the hull 11, two horizontal thrusters 23 that apply horizontal force to the hull 11, and a rudder that changes the course of the hull 11. However, the propulsion system 12 is not limited to the above configuration, and may have, for example, a swivel thruster that can change the direction of thrust generation in addition to generating thrust.

[0012] <First Magnetic Sensor> The first magnetic sensor 13 is a sensor capable of three-dimensional measurement of magnetic force. The first magnetic sensor 13 is attached to the hull 11 via an arm 26. The first magnetic sensor 13 is located forward of the hull 11 and to the right of the center line 27 that passes through the center of the hull 11 in the left-right direction. The first magnetic sensor 13 of this embodiment can measure the magnitude of the magnetic force in the X direction (magnetic flux density on a plane perpendicular to the X direction), the magnitude of the magnetic force in the Y direction (magnetic flux density on a plane perpendicular to the Y direction), and the magnitude of the magnetic force in the Z direction (magnetic flux density on a plane perpendicular to the Z direction) at the position of the first magnetic sensor 13.

[0013] In this embodiment, the "X direction" is the longitudinal direction of the hull 11, the "Y direction" is the lateral direction of the hull 11, and the "Z direction" is the vertical direction of the hull 11. In other words, in this embodiment, the X, Y, and Z directions are orthogonal to each other. The hull 11 propels along the X direction.

[0014] <Second Magnetic Sensor> The second magnetic sensor 14 is a sensor capable of three-dimensional measurement of magnetic force. The second magnetic sensor 14 has the same configuration as the first magnetic sensor 13 except for the different arrangement. The second magnetic sensor 14 is attached to the hull 11 via the arm 26. Also, the second magnetic sensor 14 is located in front of the hull 11 and to the left of the center line 27 of the hull 11. That is, the second magnetic sensor 14 is located on the opposite side of the first magnetic sensor 13 across the center line 27 of the hull 11 in a plan view. The second magnetic sensor 14 of the present embodiment can measure the magnitude of the magnetic force in the X direction, the magnitude of the magnetic force in the Y direction, and the magnitude of the magnetic force in the Z direction at the position of the second magnetic sensor 14.

[0015] <Control device> The control device 15 is a device that performs various arithmetic processes and controls various devices. The control device 15 has a processor, a volatile memory, a non-volatile memory, an I / O interface, etc. Various programs including a pipeline cross-section center position calculation program described later are stored in the non-volatile memory of the control device 15, and the processor performs arithmetic processing using the volatile memory based on each program.

[0016] As shown in FIG. 2, the control device 15 of the present embodiment is electrically connected to the first magnetic sensor 13 and the second magnetic sensor 14, and based on the measurement signals received from these magnetic sensors 13, 14, it can obtain the magnitudes of the magnetic forces in each direction measured by each of the magnetic sensors 13, 14. Further, the control device 15 is electrically connected to the propulsion system 12, and by transmitting a control signal to the propulsion system 12, it can adjust the attitude, propulsion direction, and propulsion speed of the hull 11.

[0017] The functions of the elements disclosed in this specification can be executed using a circuit or processing circuit including a general-purpose processor, a dedicated processor, an integrated circuit, an ASIC (Application Specific Integrated Circuits), a conventional circuit, and / or a combination thereof that is configured or programmed to perform the disclosed functions. Since a processor includes transistors and other circuits, it is regarded as a processing circuit or a circuit. In the present disclosure, a circuit, a unit, or a means is hardware that performs the recited functions or hardware programmed to perform the recited functions. The hardware may be the hardware disclosed in this specification or other known hardware programmed or configured to perform the recited functions. When the hardware is a processor considered to be a type of circuit, the circuit, means, or unit is a combination of hardware and software, and the software is used for configuring the hardware and / or the processor.

[0018] (Magnetic characteristics of the pipeline) As described above, the submarine 100 according to this embodiment moves along the pipeline 101 while calculating the cross-sectional center position of the pipeline 101. Here, the magnetic characteristics of the pipeline 101 will be described. FIG. 3 is a diagram for explaining the magnetic characteristics of the pipeline 101. The pipeline 101 of this embodiment is formed by connecting a plurality of individual pipes 102 made of a magnetic material. The manufacturing process of the individual pipe 102 includes a rolling process, and through the rolling process, the individual pipe 102 becomes magnetic.

[0019] Therefore, as shown in Figure 3, each individual pipe 102 can be considered a magnet with one end being a north pole and the other end being a south pole. A magnetic field is formed around the individual pipe 102, and magnetic field lines can be drawn from the north pole to the south pole as shown in Figure 3. Note that if two adjacent individual pipes 102 are connected by north pole to north pole or south pole to south pole, each individual pipe 102 can be considered as a single magnet. On the other hand, if multiple individual pipes 102 are connected by south pole to north pole, the entire group of these individual pipes 102 can be considered as a single magnet.

[0020] Here, as shown in Figure 3, we consider the direction of the magnetic force in the α plane, which is a plane perpendicular to the longitudinal direction of the individual pipe 102. Figure 4 shows the direction of the magnetic force at point A in the α plane. As shown in Figure 4, if we define the line extending vertically through the center of the cross-section of the individual pipe 102 as the "reference line," then point A is located on the "A-slope line," which is inclined at θ degrees relative to the reference line and passes through the center of the cross-section of the individual pipe 102. The direction of the magnetic force at point A coincides with the direction of extension of the A-slope line. Therefore, if we know the direction of the magnetic force at point A, that is, if we know the ratio of the vertical component to the horizontal component of the magnetic force at point A, we can determine the direction of the center of the cross-section of the pipeline 101 as seen from point A. Note that the magnetic properties of the pipeline 101 described above are the same even if the pipeline 101 is buried on the seabed.

[0021] (Program for calculating the center position of a pipeline cross-section) Next, the pipeline cross-sectional center position calculation program (hereinafter referred to as the "calculation program") performed by the control device 15 will be described. Figure 5 is a flowchart of the calculation program. The calculation program is a program that calculates the cross-sectional center position of the pipeline 101.

[0022] Figure 6 is a front view of the submersible 100 and pipeline 101, showing the positional relationship between the submersible 100 and pipeline 101 during the execution of the calculation program. As shown in Figure 6, at the start of the calculation program, the submersible 100 is positioned above pipeline 101. Furthermore, the control device 15 assumes that the submersible 100 moves along pipeline 101 while the calculation program is being executed, as shown in Figure 7. During this time, the control device 15 controls the propulsion system 12 based on the calculated cross-sectional center position of pipeline 101 so that the positional relationship between the submersible 100 and pipeline 101 remains constant. Therefore, during the execution of the calculation program, the relative positions of the first magnetic sensor 13 and the second magnetic sensor 14 and the cross-sectional center of pipeline 101 remain constant in a plane perpendicular to pipeline 101.

[0023] As shown in Figure 5, when the calculation program is started, the control device 15 first receives a measurement signal from the first magnetic sensor 13 and obtains the magnitude of the magnetic force in the Y direction and the magnitude of the magnetic force in the Z direction at the position of the first magnetic sensor 13 (step S1).

[0024] Next, the control device 15 receives a measurement signal from the second magnetic sensor 14 and obtains the magnitude of the magnetic force in the Y direction and the magnitude of the magnetic force in the Z direction at the position of the second magnetic sensor 14 (step S2).

[0025] Next, the control device 15 determines whether steps S1 and S2 described above have been performed a predetermined number of times or more (step S3). If it is determined that steps S1 and S2 have been performed a predetermined number of times or more (YES in step S3), the process proceeds to step S4. On the other hand, if it is determined that steps S1 and S2 have not been performed a predetermined number of times or more (NO in step S3), the process returns to step S1 and steps S1 and S2 are repeated.

[0026] In step S3, the "predetermined number of times" is set to two or more, for example, 20 or more times. If the predetermined number of times is small, the cross-sectional center position of pipeline 101 can be calculated in a short time, and if the predetermined number of times is large, the cross-sectional center position of pipeline 101 can be calculated with high accuracy.

[0027] Next, the control device 15 plots points (hereinafter referred to as "first coordinate points") whose coordinates are the magnitude of the magnetic force in the Y direction and the magnitude of the magnetic force in the Z direction at the position of the first magnetic sensor 13 acquired in step S1, on a coordinate plane (hereinafter referred to as "first coordinate plane") (step S4). Figure 8(a) shows the first coordinate points plotted on the first coordinate plane. In Figure 8(a), the first coordinate points for the most recent predetermined number of measurements (each with a different measurement position by the first magnetic sensor 13) are plotted.

[0028] As mentioned above, during the execution of the calculation program, the relative position of the first magnetic sensor 13 and the center of the cross-section of the pipeline 101 remains constant in a plane perpendicular to the pipeline 101. In such a case, as shown in Figure 8(a), each first coordinate point plotted on the first coordinate plane lies almost in a straight line. This is because the ratio of the magnitude of the magnetic force in the Y direction to the magnitude in the Z direction is approximately the same for each first coordinate point.

[0029] Next, the control device 15 determines the direction of the center of the cross-section of the pipeline 101 as seen from the first magnetic sensor 13 (hereinafter referred to as the "first direction") (step S5). Here, the alignment direction of each first coordinate point coincides with the direction of the magnetic force at the position of the first magnetic sensor 13. Furthermore, the direction of the magnetic force at the position of the first magnetic sensor 13 is directly opposite to the direction of the center of the cross-section of the pipeline 101 as seen from the first magnetic sensor 13 (see Figure 4). Therefore, in this embodiment, the first direction is defined as the direction that coincides with the alignment direction of the multiple first coordinate points and points downward. For example, an approximate straight line of multiple first coordinate points may be determined, and the direction that coincides with the extension direction of that approximate straight line and points downward may be defined as the first direction.

[0030] Next, the control device 15 plots points (hereinafter referred to as "second coordinate points") whose coordinates are the magnitude of the magnetic force in the Y direction and the magnitude of the magnetic force in the Z direction at the position of the second magnetic sensor 14 acquired in step S2, on a coordinate plane (hereinafter referred to as "second coordinate plane") (step S6). Figure 8(b) shows the second coordinate points plotted on the second coordinate plane. In Figure 8(b), the second coordinate points for the most recent predetermined number of times are plotted.

[0031] Next, the control device 15 determines the direction of the center position of the cross-section of the pipeline 101 as seen from the second magnetic sensor 14 (hereinafter referred to as the "second direction") (step S7). In this embodiment, as with determining the first direction, the second direction is defined as the direction that overlaps with the arrangement direction of the multiple second coordinate points plotted on the second coordinate plane and points downward.

[0032] Finally, the control device 15 calculates the cross-sectional center position of the pipeline 101 based on the first direction determined in step S5 and the second direction determined in step S7 (step S8). Specifically, the point located on both the first and second directions is defined as the cross-sectional center position of the pipeline 101. After step S8, the process returns to step S1 and steps S1 to S8 are repeated.

[0033] As described above, according to the submersible 100 of this embodiment, even when the pipeline 101 is buried on the seabed, the cross-sectional center position of the pipeline 101, that is, the position of the pipeline 101, can be accurately determined by a simple method without performing any work such as applying an electric current to the pipeline 101. Furthermore, the accuracy of calculating the cross-sectional center position of the pipeline 101 can be improved by using multiple first coordinate points and multiple second coordinate points, as in this embodiment.

[0034] (modified version) In the above embodiment, the first direction is determined based on the arrangement direction of a plurality of first coordinate points plotted on the first coordinate plane (step S5), and the second direction is determined based on the arrangement direction of a plurality of second coordinate points plotted on the second coordinate plane (step S7). However, the method for determining the first and second directions is not limited to the method described above.

[0035] For example, the first direction may be determined based on the ratio of the magnitude of the magnetic force in the Y direction to the magnitude of the magnetic force in the Z direction at the position of the first magnetic sensor 13. Similarly, the second direction may be determined based on the ratio of the magnitude of the magnetic force in the Y direction to the magnitude of the magnetic force in the Z direction at the position of the second magnetic sensor 14. According to the above method, the first and second directions can be determined with little measurement data without plotting the first and second coordinate points, and the cross-sectional center position of the pipeline 101 can be calculated in a short time.

[0036] Furthermore, although the above explanation described the case where the X, Y, and Z directions are mutually orthogonal, the X, Y, and Z directions do not necessarily have to be mutually orthogonal. For example, the Y direction may be inclined with respect to the left-right direction of the hull 11, and the Z direction may be inclined with respect to the up-down direction of the hull 11. Moreover, the Y and Z directions in the first magnetic sensor 13 do not necessarily have to coincide with the Y and Z directions in the second magnetic sensor 14. Even in such cases, the cross-sectional center position of the pipeline 101 can be calculated by correcting the measurement data of the first magnetic sensor 13 and the second magnetic sensor 14. However, if the X, Y, and Z directions are mutually orthogonal, the cross-sectional center position of the pipeline 101 can be calculated with a relatively simple calculation.

[0037] Furthermore, while the above describes the case where the submersible 100 is equipped with two magnetic sensors 13 and 14, the number of magnetic sensors that the submersible 100 may be equipped with is not limited. For example, in addition to the first magnetic sensor 13 and second magnetic sensor 14 described above, the submersible 100 may also be equipped with a third magnetic sensor and a fourth magnetic sensor. In this case, the third magnetic sensor and the fourth magnetic sensor may be located aft of the longitudinal center of the hull 11. With this configuration, the cross-sectional center position of the pipeline 101 can be calculated using the measurement data of the third magnetic sensor and the fourth magnetic sensor. This makes it possible to calculate the cross-sectional center position of the pipeline 101 based on the measurement data of magnetic sensors with different combinations. As a result, by comparing multiple calculation results, the position of the pipeline 101 can be determined more accurately. In addition, the position of the aft part of the submersible 100 relative to the pipeline 101 can also be determined, which can be used to control the attitude of the submersible 100.

[0038] (summary) The first item disclosed herein is a submersible comprising: a hull; a propulsion system that provides thrust to the hull; a first magnetic sensor attached to the hull capable of three-dimensional measurement of magnetic force; a second magnetic sensor attached to the hull at a different position from the first magnetic sensor and capable of three-dimensional measurement of magnetic force; and a control device that moves the hull along a magnetized pipeline while calculating the cross-sectional center position of the pipeline, wherein when the hull is propelled along the X direction, assuming that the direction intersecting the X direction is the Y direction and the direction intersecting the X and Y directions is the Z direction, the control device determines a first direction, which is the direction of the cross-sectional center position of the pipeline as seen from the first magnetic sensor, based on the magnitude of the magnetic force in the Y direction and the magnitude of the magnetic force in the Z direction measured by the first magnetic sensor; a second direction, which is the direction of the cross-sectional center position of the pipeline as seen from the second magnetic sensor, based on the magnitude of the magnetic force in the Y direction and the magnitude of the magnetic force in the Z direction measured by the second magnetic sensor; and calculates the cross-sectional center position of the pipeline based on the determined first and second directions.

[0039] This configuration allows for the precise location of a pipeline to be determined in a simple manner, even if the pipeline is buried on the seabed.

[0040] A second item disclosed herein is a submarine according to the first item, wherein the control device plots a plurality of points on a first coordinate plane whose coordinates are the magnitude of the magnetic force in the Y direction and the magnitude of the magnetic force in the Z direction measured by the first magnetic sensor while the hull is moving, and determines a first direction based on the arrangement direction of the plurality of points plotted on the first coordinate plane, and plots a plurality of points on a second coordinate plane whose coordinates are the magnitude of the magnetic force in the Y direction and the magnitude of the magnetic force in the Z direction measured by the second magnetic sensor while the hull is moving, and determines a second direction based on the arrangement direction of the plurality of points plotted on the second coordinate plane.

[0041] This configuration allows for a more precise understanding of the pipeline's location.

[0042] A third item disclosed herein is the submersible according to the first item, wherein the control device determines the first direction based on the ratio of the magnitude of the magnetic force in the Y direction to the magnitude of the magnetic force in the Z direction measured by the first magnetic sensor, and determines the second direction based on the ratio of the magnitude of the magnetic force in the Y direction to the magnitude of the magnetic force in the Z direction measured by the second magnetic sensor.

[0043] This configuration allows for more rapid determination of the precise location of the pipeline.

[0044] The fourth item disclosed herein is a submersible according to any one of the first to third items, wherein the X, Y, and Z directions are orthogonal to each other.

[0045] This configuration allows for the calculation of the pipeline's cross-sectional center position using relatively simple calculations.

[0046] The fifth item disclosed herein is a submersible according to any one of the first to fourth items, wherein the first magnetic sensor and the second magnetic sensor are located forward of the hull.

[0047] This configuration allows for the calculation of the cross-sectional center position of the pipeline located ahead of the hull, making it easier to control the hull's passage over the pipeline.

[0048] The sixth item disclosed herein is a submersible according to any one of the first to fifth items, wherein the first magnetic sensor and the second magnetic sensor are located on opposite sides of a centerline passing through the left-right center of the hull in a plan view.

[0049] This configuration allows for a larger angle at which the first and second directions intersect, enabling a more accurate determination of the pipeline's position. [Explanation of Symbols]

[0050] 11 Hull 12. Propulsion System 13. First Magnetic Sensor 14. Second Magnetic Sensor 15 Control device 27 Center line 100 submersibles 101 Pipelines

Claims

1. The hull and, A propulsion system that provides thrust to the hull, A first magnetic sensor, which is attached to the hull and capable of three-dimensional measurement of magnetic force, A second magnetic sensor is mounted on the hull at a different position from the first magnetic sensor and is capable of three-dimensional measurement of magnetic force. The system includes a control device that moves the ship along the magnetic pipeline while calculating the cross-sectional center position of the magnetic pipeline, The control device is When the aforementioned hull is propelled along the X direction, if the direction intersecting the X direction is the Y direction, and the direction intersecting both the X and Y directions is the Z direction, Based on the magnitudes of the magnetic force in the Y direction and the Z direction measured by the first magnetic sensor, a first direction is determined, which is the direction of the center position of the cross-section of the pipeline as seen from the first magnetic sensor. Based on the magnitudes of the magnetic force in the Y direction and the Z direction measured by the second magnetic sensor, a second direction is determined, which is the direction of the center position of the cross-section of the pipeline as seen from the second magnetic sensor. A submersible that calculates the cross-sectional center position of the pipeline based on the first and second directions obtained.

2. The control device is The first magnetic sensor plots multiple points on a first coordinate plane, using the magnitudes of the magnetic force in the Y direction and the Z direction measured by the first magnetic sensor while the ship is moving, and determines the first direction based on the arrangement direction of the multiple points plotted on the first coordinate plane. The submersible according to claim 1, wherein the second magnetic sensor plots a plurality of points on a second coordinate plane, with the magnitudes of the magnetic force in the Y direction and the magnitudes of the magnetic force in the Z direction measured by the second magnetic sensor while the hull is moving, and the second direction is determined based on the arrangement direction of the plurality of points plotted on the second coordinate plane.

3. The control device is The first direction is determined based on the ratio of the magnitude of the magnetic force in the Y direction to the magnitude of the magnetic force in the Z direction measured by the first magnetic sensor. The submersible according to claim 1, wherein the second direction is determined based on the ratio of the magnitude of the magnetic force in the Y direction to the magnitude of the magnetic force in the Z direction measured by the second magnetic sensor.

4. The submersible according to claim 1, wherein the X direction, the Y direction, and the Z direction are orthogonal to each other.

5. The submersible according to claim 1, wherein the first magnetic sensor and the second magnetic sensor are located forward of the hull.

6. The submersible according to claim 1, wherein the first magnetic sensor and the second magnetic sensor are located on opposite sides of a center line passing through the left-right center of the hull in a plan view.

Images