JP7148248B2 - Bottom-of-water exploration system, bottom-of-water exploration device, and bottom-of-water exploration method - Google Patents

Description

Application of Article 30, Paragraph 2 of the Patent Law ▲1 ▼Date December 18, 2017 ▲2▼Meeting name, Venue Symposium on next-generation marine resource survey technology 5-5-15 Kitashinagawa, Shinagawa-ku, Tokyo Osaki Bright core hole

TECHNICAL FIELD The present disclosure relates to a bottom surveying system, a bottom surveying device, and a bottom surveying method.

Techniques using an electromagnetic exploration device have been proposed in the exploration of mineral resources on the bottom of the sea, such as seabed hydrothermal deposits. For example, Patent Document 1 discloses an underwater exploration system including a submersible mobile body, a towed body towed to the submersible mobile body via a towline, and an electromagnetic exploration device arranged on the towed body. It is The electromagnetic exploration device of the bottom-of-water exploration system includes a transmission coil arranged such that a transmission loop faces the bottom of the water, and a receiver arranged around the transmission coil.

JP 2017-161390 A

In the above water bottom exploration system, it is desired to explore the physical properties of the water bottom to a deeper position. In order to deepen the searchable position in the electromagnetic survey, for example, it is conceivable to increase the area of the loop-shaped transmission coil (the area of the transmission loop).

In the underwater exploration system of Patent Document 1, a foldable horizontal wing is attached and fixed to a towing body, a transmitting coil and a receiving part (receiving coil) are attached and fixed to the tip side of the horizontal wing, and the horizontal wing is attached and fixed underwater. By unfolding the transmission coil and the reception coil, the area of the transmission loop is expanded. However, in such a configuration in which the transmission coil is mechanically expanded, if an attempt is made to increase the area of the transmission loop, the device configuration inevitably becomes large-scaled, and there is a limit to the increase in the area.

An object of the present disclosure is to provide a bottom-of-water exploration system, a bottom-of-water exploration device, and a bottom-of-water exploration method capable of expanding the area of a transmission loop for electromagnetic exploration.

The bottom-of-water exploration system according to the present disclosure includes a moving body that moves underwater, an electromagnetic exploration device that explores mineral resources on the bottom of the water, and a towing body that is towed by the moving body and moves along the survey survey line of the electromagnetic exploration device. , The electromagnetic exploration device includes a transmission coil for generating a magnetic field at the bottom of the water, a transmission unit for causing a current to flow through the transmission coil, and a change in the magnetic field caused by electromagnetic induction generated by a change in the current flowing through the transmission coil. a receiving unit for receiving information, the transmitting coil is laid in a loop on the bottom of the water, and the receiving unit attached to the tow body receives information while moving relative to the transmitting coil.

According to this bottom-of-water exploration system, since the transmission coil is laid in a loop on the bottom of the water, it is possible to expand the area of the transmission loop. In addition, the transmission coil generates electromagnetic induction under the water surface, and the receiving unit receives information on changes in the magnetic field caused by the electromagnetic induction, thereby detecting changes in electrical properties under the water surface. It is possible to explore mineral resources such as seafloor hydrothermal deposits. At this time, the receiving unit receives information about changes in the magnetic field while moving relative to the transmitting coil together with the towing body. Therefore, since the transmitting coil can form a loop independent of the towing body and the receiving part, the area of the transmitting loop can be increased compared to, for example, a configuration in which the transmitting coil and the receiving part are fixed to the towing body and cannot move relative to each other. It's easy to do. Therefore, according to the bottom-of-water exploration system, it is possible to expand the area of the transmission loop and carry out electromagnetic exploration.

The underwater exploration system may further comprise a plurality of positioning units for positioning the transmitting coils on the underwater surface. In this case, since the transmission coil is positioned on the bottom surface of the water by the plurality of positioning portions, a loop-shaped transmission coil can be easily configured.

The investigation area of the electromagnetic investigation device may include an area surrounded by the loop-shaped transmission coil and an area outside the area. In this underwater exploration system, since the receiving section receives information about changes in the magnetic field while moving relative to the transmitting coil, over an area larger than the area surrounded by the loop-shaped transmitting coil, It is possible to grasp the physical properties under the water surface.

The underwater exploration device according to the present disclosure includes a moving body configured to move in water, an electromagnetic exploration device configured to explore mineral resources on the water bottom, and a towline connected to the moving body. An electromagnetic exploration device comprising a towing body and an operation unit, comprising: a cable for forming a transmission coil that generates a magnetic field at the bottom of the water; a transmission unit configured to apply a current to the transmission coil; a receiver configured to receive information about changes in the magnetic field caused by electromagnetic induction caused by changes in the flowing current; A cable is configured to be layable on the bottom of the water, and a receiver attached to the tow body is configured to receive information while moving relative to the transmitting coil.

According to this bottom-of-water surveying apparatus, a loop-shaped transmission coil can be configured by laying a cable on the bottom of the water using the operation unit. Therefore, it is possible to expand the area of the transmission loop. In addition, the transmission coil generates electromagnetic induction under the water surface, and the reception unit receives information on changes in the magnetic field caused by the electromagnetic induction, making it possible to detect changes in electrical properties under the water surface. It is possible to explore mineral resources such as seafloor hydrothermal deposits. Here, the receiving unit is configured to receive information about changes in the magnetic field while moving relative to the transmitting coil together with the towing body. Therefore, since the cable can form a loop-shaped transmitting coil independent of the towing body and the receiving part, the area of the transmitting loop can is easier to expand. Therefore, the bottom-of-water surveying device contributes to the electromagnetic survey by expanding the area of the transmission loop.

The operating part may have a manipulator. In this case, the operation of laying the cable on the bottom of the water can be efficiently performed by the manipulator.

A plurality of positioning units may be further provided for positioning the cable on the bottom surface of the water so that the cable forms a loop, and the manipulator may be configured to perform an operation of setting the positioning units on the bottom surface of the water. In this case, the manipulator can efficiently perform the installation operation of the positioning part on the water bottom surface, and the cable can be positioned in a loop shape on the water bottom surface by the plurality of installed positioning parts. The efficiency of the laying operation can be further improved.

Further comprising a plurality of positioning parts for positioning the cable on the bottom surface of the water so that the cable forms a loop, and a plurality of holding parts for detachably holding each of the plurality of positioning parts, each of the plurality of positioning parts , it may have an insertion portion through which the cable can be inserted, and may be held by the holding portion in a state in which the cable is inserted through the insertion portion. In this case, the cable installation operation can be performed efficiently by releasing the holding state of the positioning portion by the holding portion. In addition, since the cable is inserted through the insertion portion of the installed positioning portion, it is possible to further improve the efficiency of the cable laying operation on the bottom surface of the water.

A water bottom exploration method according to the present disclosure is a water bottom exploration method for exploring mineral resources on the water bottom using any one of the water bottom exploration devices described above, wherein a cable is laid on the water bottom by an operation unit and looped on the water bottom. a step of forming a transmitting coil laid in a shape, a step of intermittently passing a current through the transmitting coil by a transmitting section to generate electromagnetic induction due to changes in the current flowing through the transmitting coil, and a towing body to which the receiving section is attached. is towed by a vehicle, and receiving information at the receiver while the receiver mounted on the tow is moving relative to the transmitting coil.

According to this underwater exploration method, any one of the underwater exploration devices described above is used to explore the mineral resources on the underwater bottom, so that the area of the transmission loop can be expanded for electromagnetic exploration.

The step of constructing a transmit coil looped on the water surface may include positioning the cable on the water surface such that the cable forms a loop. In this case, by positioning the cables, the cables can be efficiently laid on the bottom surface of the water.

In this water bottom exploration method, the water bottom exploration device further comprises a plurality of positioning units for positioning the cable on the bottom of the water so that the cable forms a loop, forming a transmission coil laid in a loop on the bottom of the water. In the step, the cable may be positioned at the bottom of the water by dropping the positioning part together with the cable to the bottom of the water. In this case, since the installation operation of the positioning portion and the cable laying operation are performed in parallel, the cable can be laid on the bottom surface of the water more efficiently.

Advantageous Effects of Invention According to the present disclosure, it is possible to provide a bottom-of-water exploration system, a bottom-of-water exploration device, and a bottom-of-water exploration method that enable electromagnetic exploration with a larger transmission loop area.

FIG. 1 is a perspective view showing a bottom-of-water exploration device according to this embodiment. FIG. 2 is a side view showing the underwater exploration device according to this embodiment. 3 is a plan view showing the transmitter unit and cable unit of FIG. 1. FIG. FIG. 4 is an enlarged view of region IV in FIG. 2, where (a) is a perspective view and (b) is a side view. FIG. 5 is a plan view schematically showing each step (installation of positioning jigs) of the underwater exploration method. FIG. 6 is a plan view schematically showing each step (cable laying) of the underwater exploration method. FIG. 7 is a perspective view schematically showing a bottom-of-water exploration system to which the bottom-of-water exploration device is applied. FIG. 8 is a diagram showing a modified example of the jig support portion and the positioning jig.

Hereinafter, embodiments according to the present disclosure will be described in detail with reference to the drawings. In the drawings, the same reference numerals are given to the same elements or elements having the same function, and redundant description may be omitted. Since the embodiments according to the present disclosure described below are examples for explaining the present invention, the present invention should not be limited to the following.

[Underwater Exploration Equipment]
A water bottom exploration device 1 according to the present embodiment will be described with reference to FIGS. 1 to 4. FIG. The seabed exploration device 1 is a device for exploring mineral resources on the seabed such as seabed hydrothermal deposits. As shown in FIGS. 1 and 2, the underwater exploration apparatus 1 includes a moving body 10, a storage unit 20 attached below the moving body 10, a towing body 30 stored in the storage unit 20, and a storage unit 20. and an electromagnetic exploration device 40 mounted on the towing body 30, an operation unit 50 attached to the storage unit 20 so as to be positioned on the front side of the underwater exploration device 1 in the propulsion direction D1, and the rear of the storage unit 20 in the propulsion direction D1. and a plurality of positioning jigs 60 (positioning portions) disposed so as to be positioned at

The moving body 10 is configured to move in water. The moving body 10 has a buoyant body 11 and a body portion 12 . The buoyant body 11 is fixed to the upper portion of the body portion 12 . The body portion 12 has, for example, a thruster (not shown). The moving body 10 is propelled in the propelling direction D1 in the water by driving the thrusters. In the following description, the front in the propulsion direction D1 of the underwater exploration apparatus 1 will be referred to as "front", and the rear in the propulsion direction D1 will be referred to as "rear". be.

The moving body 10 is, for example, an ROV (Remotely operated vehicle). The moving body 10 can be data-communicated with a mother ship (not shown) running on water via a cable or the like, so that the moving body 10 may be propelled by being remotely controlled by an operator from the mother ship. Note that the moving body 10 may be a submersible or the like operated by a crew member.

The storage unit 20 is arranged below the mobile body 10 and stores the towing body 30 . For example, the storage unit 20 is attached to the mobile body 10 . As shown in FIGS. 1 and 2, for example, the storage unit 20 is connected to the moving body 10 by a plurality of connecting members 20a. The storage unit 20 includes a body portion 21 forming a storage space S for storing the towing body 30, a connection portion 22 connecting the body portion 21 and the towing body 30 stored in the storage space S, and the underwater exploration device 1. A facility support portion 23 attached to the body portion 21 so as to be positioned on the front side, a jig support portion 24 attached to the rear side of the body portion 21, and between the body portion 21 and the moving body 10 above the body portion 21. and a towline store 25 positioned thereon.

The body portion 21 forms a substantially rectangular parallelepiped storage space S whose longitudinal direction is the propelling direction D1. The main body 21 is, for example, a frame body, and has a pair of side frames 21 a and 21 b that partition the front and rear of the storage space S, and a connection frame 21 c that partitions the upper portion of the storage space S. The side frames 21a and 21b face each other below the moving body 10 in the propelling direction D1. The side frame 21 a is located on the front side of the underwater bottom surveying device 1 , and the side frame 21 b is located on the rear side of the underwater bottom surveying device 1 . The connection frame 21c spans between the upper ends of the side frames 21a and 21b, and connects the upper ends of the side frames 21a and 21b. As a result, an area surrounded by the main body 21 and the side frames 21a and 21b is formed as a storage space S. As shown in FIG.

The connecting portion 22 connects the towing body 30 stored in the storage space S and the main body portion 21 . The connecting portion 22 has a support portion 22a and auxiliary portions 22b and 22c. The support portion 22a is attached to a substantially central portion of the connection frame 21c in the propulsion direction D1, and supports the towing body 30 in the storage space S by suspending it. The auxiliary parts 22b and 22c are attached to the lower ends of the side frames 21a and 21b, respectively, and support the towing body 30 from the front or rear.

The facility support portion 23 is attached to the main body portion 21 and supports a part of the electromagnetic investigation device 40 (a cable unit 41 and a transmitter unit 42 which will be described later). The facility support portion 23 is arranged, for example, in front of the side frame 21a. FIG. 3 is a plan view of the transmitter unit 42 and the cable unit 41 of FIGS. 1 and 2 viewed from above, and shows that the right direction of the paper surface is the propelling direction D1. As shown in FIG. 3, the equipment support section 23 has mounting tables 23a and 23b. The mounting table 23a has a mounting plate 23c, and the cable unit 41 is mounted on the mounting plate 23c. The mounting table 23b has a mounting plate 23d, and the transmitter unit 42 is mounted on the mounting plate 23d.

The mounting plates 23c and 23d are made of grating, for example. The mounting plates 23c and 23d are formed with a large number of holes (not shown) penetrating in the direction of their thickness. The water pressure acting on the containment unit 20 is reduced.

The jig support section 24 supports a plurality of positioning jigs 60 on the rear side of the underwater exploration apparatus 1, as shown in FIGS. 1 and 4(a). The jig support portion 24 is provided behind the side frame 21b, for example. The jig support portion 24 includes fixed rods 24a that suspend and support the plurality of positioning jigs 60, horizontal members 24b that support the fixed rods 24a, and fixed frames 24c that fix the horizontal members 24b to the side frames 21b. , have The fixed frame 24c is attached to the upper end of the side frame 21b, and the horizontal member 24b is fixed to the fixed frame 24c along the upper end of the side frame 21b. A plurality of through holes (not shown) are formed in the horizontal member 24b so as to penetrate in the thickness direction (propulsion direction D1). The fixed rod 24a is supported by the horizontal member 24b by being inserted through the through hole.

The towline storage section 25 is mounted on the connection frame 21c between the main body section 21 and the moving body 10. As shown in FIG. A towline 31 for towing a towing body 30 is stored in the towline storage section 25 . The towline storage unit 25 incorporates, for example, a winch (not shown). The towline storage part 25 stores the towline 31 in a state in which the towline 31 is wound around the winch.

A tow body 30 is connected to the mobile body 10 via a towline 31 . That is, the remaining end of the towline 31 is connected to the tow body 30 . The tow body 30 has a bottom plate 32 , a cover 33 and a towing section 34 . The bottom plate 32 has, for example, a rectangular shape, and is arranged along an imaginary line connecting the lower end of the side frame 21a and the lower end of the side frame 21b. The bottom plate 32 is composed of grating, for example. The bottom plate 32 is formed with a large number of holes penetrating in its thickness direction, and when the underwater exploration device 1 is submerged, the water pressure acting on the towing body 30 is increased by the water passing through the large number of holes. reduced.

The cover 33 is attached to the bottom plate 32 so as to cover the front end of the bottom plate 32 . The cover 33 is provided so that its thickness becomes thinner toward the front in a side view. This reduces the water resistance acting on the tow body 30 as it moves in the direction of propulsion D1. The towing part 34 has an upper plate 34 a to which the towline 31 is attached and a fixing part 34 b that fixes the upper plate 34 a to the bottom plate 32 . Thereby, the towing body 30 and the towline 31 are connected.

The electromagnetic exploration device 40 is configured to explore mineral resources on the bottom of the water (for example, the bottom of the sea). As shown in FIG. 3, the electromagnetic surveying device 40 includes a cable unit 41 and a transmitter unit 42 (transmitting section) arranged adjacent to each other on the front side of the underwater surveying device 1, and a bottom plate 32 of the towing body 30. It has a receiver 43 (receiving section) attached to the top surface.

The cable unit 41, as shown in FIGS. 1-3, has a drum 41a, a handle 41b, and a cable 41c. The drum 41a winds and houses the cable 41c. The drum 41a is mounted on the mounting plate 23c of the equipment support portion 23 connected to the side frame 21a so as to protrude forward of the underwater exploration device 1. As shown in FIG. The drum 41a is rotatably arranged around a rotation axis Ax intersecting the driving direction D1 so that the cable 41c can be unwound in the driving direction D1. The handle 41b is installed in front of the drum 41a on the mounting table 23a. The handle 41b is connected to the drum 41a via, for example, a chain. Drum 41a is rotated by handle 41b to unwind and wind cable 41c.

The cable 41c is an electric wire for configuring the transmission coil 44 (see FIG. 7). The cable 41c constitutes the transmission coil 44 by being laid in a loop on the bottom of the water (for example, the bottom of the sea 90s shown in FIG. 7). For example, the cable 41c is composed of a conductor (not shown) covered with an insulating film (not shown). As a result, when the transmission coil 44 is installed underwater (for example, in the sea), the transmission coil 44 can be reliably insulated from seawater.

The transmission coil 44 is configured to generate a magnetic field (hereinafter referred to as "primary magnetic field") on the seabed (for example, the seabed 90 shown in FIG. 7) by applying an electric current. The number of turns of the transmission coil 44 may be, for example, one or multiple. The transmission coil 44 is laid on the seabed 90s in a loop shape, and a portion surrounded by the looped transmission coil 44 (hereinafter referred to as "coil surface") faces the seabed 90s. Specifically, the transmission coil 44 is laid in a loop on the seabed 90s so that the normal direction of the coil surface is on the seabed 90s. Note that the loop shape means a ring shape forming a closed region, and may be, for example, a rectangular ring shape, a circular ring shape, or a shape forming a polygonal outline.

Returning to FIG. 3, transmitter unit 42 is configured to energize transmit coil 44 . As shown in FIG. 3, the transmitter unit 42 has a transmission power supply 42a, a controller 42b, a switch 42c and a connector 42d. The transmission power source 42a, the control device 42b, and the switch 42c are mounted on the mounting plate 23d of the equipment support portion 23. As shown in FIG. The transmission power supply 42 a is a source of current that flows through the transmission coil 44 . The current supplied to the transmission coil 44 by the transmission power supply 42a is, for example, several tens of amperes to several hundred amperes, and may be changed according to the purpose of the search.

The control device 42b controls the transmission power source 42a. For example, the control device 42b controls the transmission power source 42a so as to change the current that flows from the transmission power source 42a to the transmission coil 44. FIG. The control device 42b controls the transmission power source 42a, for example, so as to repeat a state in which the current is supplied to the transmission coil 44 and a state in which the current is suddenly interrupted. The transmission power supply 42a generates electromagnetic induction under the seabed 90s by changing the current flowing through the transmission coil 44 .

Returning to FIGS. 1 to 3, the switch 42c switches between activation and deactivation of the control device 42b for controlling the current flowing from the transmission power supply 42a to the transmission coil 44. FIG. The connector 42d electrically connects the transmission coil 44 and the transmission power source 42a when the transmission coil 44 is configured by the cable 41c.

A receiver 43 mounted on the upper surface of the bottom plate 32 of the tow body 30 is configured to receive information regarding changes in the magnetic field. Receiver 43 is, for example, a magnetic field sensor. As described above, electromagnetic induction is generated by changing the current that the transmission power supply 42a supplies to the transmission coil 44. FIG. The receiver 43 receives information about changes in the magnetic field due to this electromagnetic induction. The information about changes in the magnetic field is information about changes in the magnetic field over time, and may be, for example, the amount of change in the magnetic field (time differential value) or the magnitude of the magnetic field itself at a plurality of points in time. The receiver 43 is mounted on the top surface of the bottom plate 32 of the tow body 30 as shown in FIGS.

The operation section 50 is connected to the main body section 21 of the storage unit 20 on the front side of the underwater exploration device 1 . The operation unit 50 is configured such that the cable 41c can be laid on the bottom of the water (for example, the bottom of the sea 90s shown in FIG. 7) so that the cable 41c forms a loop-shaped transmission coil 44 . As shown in FIGS. 1 and 2, the operation unit 50 has a pair of manipulators 51, for example. Each manipulator 51 is remotely operated, for example, to perform an operation of laying the cable 41c on the seabed 90s, an operation of installing the positioning jig 60 on the seabed 90s, and an operation of switching the start and stop of the control device 42b by the switch 42c. is configured to perform Note that the operation unit 50 may include a motor or the like for driving the rotation of the drum 41a.

A plurality of (for example, four) positioning jigs 60 attached to the jig support portion 24 of the storage unit 20 on the rear side of the underwater exploration apparatus 1 extend the cable 41c to the bottom of the water so that the cable 41c forms a loop. It is a positioning member. As shown in FIG. 4A, the plurality of positioning jigs 60 are arranged along the side frame 21b behind the storage unit 20. As shown in FIG. As shown in FIG. 4B, the positioning jig 60 has a wire 61, a float 62, a weight 63, and a hook 64. The wire 61 is hooked on the fixed rod 24a at its upper end. As a result, the positioning jig 60 is separated from the jig support portion 24 simply by moving the fixed rod 24 a forward by the manipulator 51 .

A float 62 is attached to one end (for example, the upper end) of the wire 61 . The weight 63 is composed of, for example, a large number of lead balls (not shown) and a containing bag 63a containing the lead balls. A weight 63 is attached to the other end (for example, the lower end) of the wire 61 . Hook 64 is attached to wire 61 between float 62 and weight 63 . The hook 64 is attached to the wire 61 so that the curved portion faces the upper end side and the tip portion faces the lower end side. As a result, the positioning jig 60 is installed so as to maintain a posture in which the weight 63 is positioned downward and the float 62 is positioned upward on the underwater surface (for example, the sea surface 90s in the sea). Therefore, the cable 41c is caught on the hook 64 when the cable 41c floats up from the bottom of the water (for example, the bottom of the sea 90s). As a result, further movement of the cable 41c above the hook 64 is restricted, and the shape of the loop-shaped transmission coil 44 can be maintained.

[Underwater Exploration Method]
Next, with reference to FIGS. 5 to 7, a water bottom exploration method for exploring mineral resources on the water bottom using the above-described water bottom exploration device 1 will be described. As an example, a case of exploring a hydrothermal deposit on the seabed 90 will be described below. The underwater exploration method is performed in a state in which the underwater exploration device 1 is submerged from the exploration area of the seabed 90s in seawater to a predetermined altitude. The underwater exploration method includes an installation process, a transmission process and a reception process.

In the installation process, as shown in FIG. 5(a), first, the positioning jig 60 is installed on the seabed 90s. Specifically, the moving body 10 moves the underwater exploration device 1 along the sea floor 90s in the retreating direction D2 opposite to the propelling direction D1, and the transmission coil 44 is laid at a position (for example, a rectangular ring laying position P). ), the positioning jig 60 is installed by the manipulator 51 (see FIGS. 1 and 2). The positioning jig 60 is installed, for example, at each corner portion C (for example, three corner portions C) at the laying position P. As shown in FIG. For example, the positioning jig 60 is separated from the jig support portion 24 (see FIGS. 1 and 2) while the bottom surveying apparatus 1 is positioned above each corner portion C. As shown in FIG. Specifically, the manipulator 51 grips the fixed rod 24a (see FIGS. 2 and 4) to move the fixed rod 24a forward. By dropping the positioning jig 60 onto the seabed 90s, the manipulator 51 performs the installation operation of the positioning jig 60 on the seabed 90s.

Next, as shown in FIG. 5(b), the transmitter unit 42 is installed on the seabed 90s. For example, the transmitter unit 42 may be installed by the manipulator 51 at one of the four corners. One end of the cable 41c is connected to the transmitter unit 42 in advance.

Next, as shown in FIGS. 5(b) and 6(a), starting from the transmitter unit 42, the operating unit 50 is moved along the sea floor 90s by the moving body 10. By laying the cable 41c on the seabed 90s, a transmission coil 44 laid in a rectangular ring shape on the seabed 90s is constructed. Specifically, the handle 41b is gripped by the manipulator 51 to rotate the drum 41a, and the cable 41c is laid on the sea floor 90s while unwinding the cable 41c. At this time, the cable 41c is laid on the sea floor 90s while being positioned by the positioning jig 60 at the corner portion C so that the cable 41c forms a rectangular loop. Specifically, the cable 41c is arranged on the sea floor 90s so that the cable 41c surrounds the corner portion C from the outside of the laying position P. As shown in FIG. As a result, the movement of the cable 41c toward the inside of the laying position P is restricted by the positioning jig 60. As shown in FIG.

After the cable 41c is laid, finally, the other end of the cable 41c is connected to the transmitter unit 42 using the connector 42d (see FIG. 3), as shown in FIG. 6(b). The connection operation is performed by, for example, the manipulator 51 (see FIGS. 1 and 2). With the above, the installation process is completed.

The transmission process is performed by operating the switch 42c (see FIG. 3) by the manipulator 51 after the installation process described above is completed, and activating the control device 42b (see FIG. 3). In the transmission process, the transmitter unit 42 intermittently causes current to flow through the transmission coil 44 , and changes in the current flowing through the transmission coil 44 cause electromagnetic induction.

In the receiving process, the towed body 30 to which the receiver 43 is attached is towed by the mobile body 10, and information is received by the receiver 43 while the receiver 43 attached to the towed body 30 moves relative to the transmission coil 44. Receive (see FIG. 7). Details of the transmission process and the reception process will be described below.

First, in the transmitter unit 42, the manipulator 51 (see FIGS. 1 and 2) operates the switch 42c (see FIG. 3) to activate the controller 42b (see FIG. 3). The control device 42b controls the transmission power supply 42a (see FIG. 3) so as to change the current that flows through the transmission coil 44 from the transmission power supply 42a. As a result, a magnetic field (primary magnetic field) is generated around the transmission coil 44, the magnetic field changes, and an induced current is generated under the sea floor 90s. The induced current diffuses under the sea floor 90s and attenuates according to the specific resistance of the medium at the position where the current flows. Therefore, by receiving information about changes in the magnetic field generated by this induced current (hereinafter referred to as "secondary magnetic field") by the receiver 43, the attenuation of the magnetic field can be detected as a time change of the magnetic field, and the It is possible to know the specific resistance of the medium.

For example, when the medium under the seafloor 90s has a high resistivity (for example, when mineral resources do not exist), the secondary magnetic field rapidly attenuates, but when it has a low resistivity (for example, when mineral resources exist) ) decays slowly. In this way, exploration of mineral resources, such as submarine hydrothermal deposits, on the seabed 90 is enabled.

In the exploration process according to this embodiment, the receiver 43 continuously receives information on changes in the secondary magnetic field at each measurement point along the survey survey line L. FIG. Specifically, the towed body 30 to which the receiver 43 is attached is towed by the mobile body 10 to move the towed body 30 along the survey survey line L. Then, while the receiver 43 attached to the towing body 30 is moved relative to the transmission coil 44, the receiver 43 receives information on changes in the secondary magnetic field at each measurement point. In this way, information about changes in the secondary magnetic field is received at all measurement points in the surveyed area of the sea bed 90 .

[Underwater Exploration System]
Next, with reference to FIG. 7, a water bottom exploration system 100 installed using the water bottom exploration device 1 described above will be described. As shown in FIG. 7, the bottom-of-water exploration system 100 includes a bottom-of-water exploration device 1 installed underwater (for example, in the sea). The moving body 10 is moving in water. The electromagnetic exploration device 40 explores mineral resources on the bottom of the water (for example, the bottom of the sea 90). The towing body 30 is towed by the moving body 10 and is moving along the survey survey line L of the electromagnetic exploration device 40 .

The transmission coil 44 of the electromagnetic exploration device 40 is laid in a loop on the seabed 90s. In FIG. 7, the receiver 43 attached to the towing body 30 receives information about changes in the secondary magnetic field while moving relative to the transmitting coil 44 . Specifically, after receiving information about changes in the secondary magnetic field at one measurement point along the survey line L, the receiver 43 moves relative to the transmitter coil 44 and moves to another location along the survey line L. Receive the relevant information at the measurement point.

Also, the plurality of positioning jigs 60 position the transmission coil 44 on the seabed 90s. Further, as shown in FIG. 7, for example, the towing body 30 moves along the survey survey line L at a predetermined altitude H from the seabed 90s, which is the survey area of the electromagnetic survey device 40 . The region in which the tow body 30 moves may include the region surrounded by the loop-shaped transmitting coil 44 and the region outside this region. That is, the exploration area explored by the electromagnetic exploration device 40 may include an area surrounded by the loop-shaped transmission coil 44 and an area outside the area.

[Effect of this embodiment]
The bottom-of-water exploration system 100 according to the present embodiment includes a mobile body 10 that moves in the sea, an electromagnetic exploration device 40 that explores mineral resources on the seabed 90, and is towed by the mobile body 10, and along an exploration survey line L of the electromagnetic exploration device 40. a tow body 30 moving along. The electromagnetic exploration device 40 includes a transmission coil 44 for generating a primary magnetic field on the seabed 90, a transmitter unit 42 for causing a current to flow through the transmission coil 44, and electromagnetic induction caused by changes in the current flowing through the transmission coil 44. a receiver 43 for receiving information about changes in the secondary magnetic field. The transmission coil 44 is laid in a loop on the seabed 90 s, and the receiver 43 attached to the towing body 30 receives information while moving relative to the transmission coil 44 .

According to this seabed exploration system 100, since the transmission coil 44 is laid in a loop on the seabed 90s, it is possible to expand the area of the transmission loop. In addition, the transmission coil 44 generates electromagnetic induction under the seabed 90s, and the receiver 43 receives information on the change in the secondary magnetic field caused by the electromagnetic induction, so that the electrical properties under the seabed 90s It is possible to detect changes in , and explore mineral resources such as seafloor hydrothermal deposits. At this time, the receiver 43 receives information about changes in the secondary magnetic field while moving relative to the transmission coil 44 together with the towing body 30 . Therefore, since the transmitting coil 44 can form a loop independent of the towing body 30 and the receiver 43, for example, compared to a configuration in which the transmitting coil 44 and the receiver 43 are fixed to the towing body 30 and cannot move relative to each other, Easy to expand the transmission loop area. Therefore, according to the bottom-of-water exploration system 100, it is possible to expand the area of the transmission loop for electromagnetic exploration.

The underwater exploration system 100 described above further includes a plurality of positioning jigs 60 for positioning the transmission coils 44 on the seabed 90s. As a result, the transmission coil 44 is positioned on the sea floor 90s by the plurality of positioning jigs 60, so that the loop-shaped transmission coil 44 can be easily constructed.

The survey survey line L is set at a predetermined altitude from the survey area of the seabed 90, and the survey area includes an area surrounded by the loop-shaped transmission coil 44 and an area outside this area. In this underwater exploration system 100 , the receiver 43 receives information about changes in the secondary magnetic field while moving relative to the transmission coil 44 , so the area is larger than the area surrounded by the loop-shaped transmission coil 44 . It is possible to grasp the physical properties under the sea floor 90s over the area of .

The underwater exploration device 1 according to the present embodiment includes a moving body 10 configured to move underwater (under the sea), an electromagnetic exploration device 40 configured to explore mineral resources on the water bottom (seabed 90), A tow body 30 connected to the mobile body 10 via a towline 31 and an operation unit 50 are provided. The electromagnetic exploration device 40 includes a cable 41c for configuring a transmission coil 44 that generates a primary magnetic field on the seabed 90, a transmitter unit 42 configured to cause current to flow through the transmission coil 44, and a current flowing through the transmission coil 44. a receiver 43 configured to receive information about changes in the secondary magnetic field due to electromagnetic induction caused by changes in the . The operation unit 50 is configured such that the cable 41 c can be laid on the seabed 90 s so as to form a loop-shaped transmission coil 44 with the cable 41 c. and is configured to receive information about changes in the secondary magnetic field while moving relative to it.

According to this underwater exploration apparatus 1, the cable 41c can be laid on the seabed 90s by the operation unit 50 to configure the loop-shaped transmission coil 44. FIG. Therefore, it is possible to expand the area of the transmission loop. In addition, the transmission coil 44 generates electromagnetic induction under the seabed 90s, and the receiver 43 receives information on the change in the secondary magnetic field caused by the electromagnetic induction, so that the electrical properties under the seabed 90s It is possible to detect changes in , and explore mineral resources such as seafloor hydrothermal deposits. Here, the receiver 43 is configured to receive information about changes in the secondary magnetic field while moving relative to the transmission coil 44 together with the towing body 30 . Therefore, since the cable 41c can form a loop-shaped transmission coil 44 independent of the towing body 30 and the receiver 43, for example, compared to a configuration in which the transmission coil 44 and the receiver 43 are fixed to the towing body 30 and cannot move relative to each other. As a result, it is easier to expand the area of the transmission loop. Therefore, the bottom-of-water surveying apparatus 1 can expand the area of the transmission loop for electromagnetic surveying, which contributes to grasping the physical properties of the bottom of the sea 90s to a deeper position.

The operation unit 50 has a manipulator 51 . By having the manipulator 51, the laying operation of the cable 41c to the sea floor 90s can be efficiently performed.

Further provided are a plurality of positioning jigs 60 for positioning the cable 41c on the seabed 90s so that the cable 41c forms a loop, and the manipulator 51 is configured to perform the work of installing the positioning jigs 60 on the seabed 90s. may be In this case, the positioning jig 60 can be efficiently installed on the seabed 90s by the manipulator 51, and the cable 41c can be positioned in a loop on the seabed 90s by the plurality of installed positioning jigs 60. Therefore, the efficiency of the laying operation of the cable 41c to the seabed 90s can be further improved.

The bottom-of-water exploration method according to the present embodiment is a bottom-of-water exploration method for exploring mineral resources on the seabed 90 using the bottom-of-water exploration device 1 described above. The underwater exploration method includes steps of laying the cable 41c on the seabed 90s by the operation unit 50 to form the transmission coil 44 laid in a loop on the seabed 90s, and connecting and disconnecting the transmission coil 44 by the transmitter unit 42. a step of causing a change in the current flowing through the transmission coil 44 to generate electromagnetic induction; receiving information about changes in the magnetic field at the receiver 43 while moving 43 relative to the transmitter coil 44 .

According to this water bottom exploration method, the underwater mineral resources are explored using the water bottom exploration device 1, so the area of the transmission loop can be expanded for electromagnetic exploration.

In the step of forming the transmission coil 44 laid in a loop on the seabed 90s, the cable 41c is positioned on the seabed 90s so that the cable 41c forms a loop. In this case, the cable 41c can be efficiently laid on the sea floor 90s by positioning the cable 41c.

[Modification]
Although the embodiments according to the present disclosure have been described above, the present invention is not limited to the above embodiments. FIG. 8 is a diagram showing a modified example of the jig supporting portion and the positioning jig, and is a diagram when the region IV in FIG. 2 is viewed from the rear. As shown in FIG. 8, the jig support section 24 supports each of the transmitter unit 42 and a plurality of (for example, four) positioning jigs 60 on the rear side of the underwater exploration apparatus 1 (behind the storage unit 20). It may have a plurality of (for example, five) holding mechanisms 24d (holding portions) that are detachably held. The plurality of holding mechanisms 24d are attached, for example, to the fixed frame 24c. The holding mechanism 24 d may be configured to grip each positioning jig 60 or may be configured to suck each positioning jig 60 .

Each positioning jig 60 has a suspension ring 65 (insertion portion) on the upper end of the wire 61 through which the cable 41c can be inserted. One end of the cable 41c is connected to the transmitter unit 42, and the suspension ring 65 of each positioning jig 60 is movably inserted. That is, the positioning jig 60 is held by the holding mechanism 24d with the cable 41c inserted through the suspension ring 65. As shown in FIG. According to the configuration according to the modification, the installation operation of the cable 41c can be efficiently performed by releasing the holding state of the positioning jig 60 by the holding mechanism 24d. In addition, since the cable 41c is inserted through the sling ring 65 of the positioning jig 60 installed, the efficiency of the laying operation of the cable 41c to the sea floor 90s can be further improved.

In the installation step of the underwater exploration method, the underwater exploration apparatus 1 is moved along the seabed 90s where the positioning jig 60 is not installed, while unwinding the cable 41c. By dropping the positioning jig 60 onto the seabed 90s, the cable 41c may be positioned on the seabed 90s and the transmitting coil 44 may be laid on the seabed 90s. At this time, the positioning jig 60 may be dropped by operating the manipulator 51, or by releasing the held state of the positioning jig 60 by the holding mechanism 24d. According to this underwater exploration method, since the installation operation of the positioning jig 60 and the laying operation of the cable 41c are performed in parallel, the cable 41c can be laid on the seabed 90s more efficiently.

DESCRIPTION OF SYMBOLS 1... Underwater exploration apparatus 10... Mobile body 11... Buoyant body 12... Main body part 20... Storage unit 20a... Connection member 21... Main body part 21a, 21b... Side frame 21c... Connection frame 22... Connection part 22a Support part 22b, 22c Auxiliary part 23 Equipment support part 23a, 23b Placement base 23c, 23d Placement plate 24 Jig support 24a Fixed rod 24b Horizontal member 24c Fixed frame 24d Holding mechanism (holding part) 25 Towline storage part 30 Towing body 31 Towline 32 Bottom plate 33 Cover 34 Towing part 34a Upper plate 34b Fixed part 40 Electromagnetic investigation device 41 Cable unit 41a Drum 41b Handle 41c Cable 42 Transmitter unit (transmitter) 44 Transmitter coil 42a Transmitter power supply , 42b... control device, 42c... switch, 42d... connector, 43... receiver (receiving unit), 44... transmission coil, 50... operation unit, 51... manipulator, 60... positioning jig, 61... wire, 62... float , 63... Weight, 63a... Accommodating bag, 64... Hook, 65... Suspension ring (insertion part), 90... Seabed (bottom of water), 90s... Seabed (bottom of water), 100... Underwater exploration system, C... Corner part, D1...Propulsion direction, D2...Retreat direction, H...Altitude, L...Exploration survey line, P...Laying position, S...Storage space.

Claims (11)

a moving body that moves in water;
an electromagnetic exploration device for exploring mineral resources on the bottom of the water;
a towing body that is towed by the moving body and moves along the survey survey line of the electromagnetic survey device;
The electromagnetic exploration device is
a transmission coil for generating a magnetic field at the bottom of the water;
a transmission unit that applies current to the transmission coil;
a receiver attached to the tow body for receiving information about changes in the magnetic field caused by electromagnetic induction caused by changes in the current flowing through the transmitting coil;
The transmission coil is laid in a loop on the bottom surface of the water,
The underwater exploration system, wherein the receiving unit receives the information while moving relative to the transmitting coil. 2. The underwater exploration system of claim 1, further comprising a plurality of positioning units for positioning the transmitting coils on the bottom surface of the water. 3. The bottom-of-water exploration system according to claim 2, further comprising a jig support section that is arranged below the moving body and attached to a storage unit that stores the towing body, and that supports the positioning section in a detachable manner. The underwater exploration system according to any one of claims 1 to 3, wherein the exploration area of said electromagnetic exploration device includes an area surrounded by said loop-shaped transmission coil and an area outside said area. a moving body configured to move in water;
an electromagnetic exploration device configured to explore underwater mineral resources;
a towing body connected to the moving body via a towline;
and an operation unit,
The electromagnetic exploration device is
a cable for forming a transmission coil that generates a magnetic field at the bottom of the water;
a transmitter configured to apply current to the transmitter coil;
a receiver attached to the tow body and configured to receive information about changes in the magnetic field caused by electromagnetic induction caused by changes in the current through the transmit coil;
The operation unit is configured to be able to lay the cable on the bottom surface of the water so that the cable forms the loop-shaped transmission coil,
The underwater exploration device, wherein the receiving unit is configured to receive the information while moving relative to the transmitting coil. 6. The underwater exploration device according to claim 5 , wherein said operation unit has a manipulator. further comprising a plurality of positioning units for positioning the cable on the bottom surface of the water so that the cable forms a loop;
The bottom-of-water exploration apparatus according to claim 6 , wherein said manipulator is configured to perform a task of installing said positioning part on said bottom surface of water. a plurality of positioning units for positioning the cable on the bottom surface of the water so that the cable forms a loop;
further comprising a plurality of holding portions that detachably hold each of the plurality of positioning portions,
8. The underwater exploration according to claim 7 , wherein each of the plurality of positioning portions has an insertion portion through which the cable can be inserted, and is held by the holding portion in a state in which the cable is inserted through the insertion portion. Device. A bottom-of-water exploration method for exploring mineral resources on the bottom of the water using the bottom-of-water exploration device according to any one of claims 5 to 8 ,
Laying the cable on the bottom surface of the water by the operation unit to configure the transmission coil laid in a loop shape on the bottom surface of the water;
a step of intermittently passing a current through the transmission coil by the transmission unit, and generating electromagnetic induction due to changes in the current flowing through the transmission coil;
a step of towing the towing body to which the receiving section is attached by the moving body, and receiving the information by the receiving section while moving the receiving section attached to the towing body relative to the transmitting coil; and, a method of underwater exploration, comprising: 10. The underwater exploration method according to claim 9 , wherein in the step of forming the transmission coil laid in a loop on the water bottom, the cable is positioned on the water bottom so that the cable forms a loop. The bottom-of-water exploration device further comprises a plurality of positioning units for positioning the cable on the bottom of the water so that the cable forms a loop,
11. The method according to claim 10 , wherein in the step of configuring the transmission coil laid in a loop on the water bottom surface, the cable is positioned on the water bottom surface by dropping the positioning portion together with the cable onto the water bottom surface. method of underwater exploration.

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