Underwater survey device

Abstract

To provide an underwater investigation device capable of accurately and efficiently investigating a topographical situation in the periphery of a structure installed in the water, despite its simple configuration.SOLUTION: An underwater investigation device A that is one example of an underwater investigation device applying the present invention, comprises a control mechanism 1, a body device part 2, and a tether cable 3. Further, the body device part 2 includes a moving device body 20, an imaging sonar 21, and a gimbal device 22. The gimbal device 22 has a first arm 222 and a second arm 223. The first arm 222 is a member that rotates a direction of the imaging sonar 21 using a rotation axis of a direction parallel to an X-axis direction as a center, in an initial state where a direction of the imaging sonar 21 is directed perpendicularly downward. Further, the second arm 223 is a member that rotates a direction of the imaging sonar 21 using a rotation axis of a direction parallel to a Y-axis direction as a center.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an underwater survey device. More specifically, the present invention relates to an underwater survey device that, while having a simple mechanism, can accurately and efficiently survey the terrain around a structure installed underwater.

Background Art

[0002] In recent years, due to heavy rain disasters, a phenomenon called scouring has occurred in which the sediment on the riverbed is washed away from the bridge piers of bridges provided in rivers and the like, and incidents in which bridges become unusable have occurred.

[0003] For example, during the flood caused by Typhoon No. 14 in September 2022, damage to the "Kuma Bridge" on the prefectural road Kakoi-Ikeda Line, which is managed by Kumamoto Prefecture, occurred on the first-class river Kuma River, and the bridge was closed to traffic.

[0004] In addition, as a result of investigating the above-mentioned Kuma Bridge, it was found that the foundation part of the bridge pier was constructed as designed, and no defects were found in the bridge other than settlement due to scouring.

[0005] With such disasters caused by heavy rain, if a bridge has to be replaced, construction costs of several billion yen will be incurred.

[0006] Regarding the occurrence of scouring associated with such heavy rain disasters, it may be possible to avoid disasters by investigating the scouring situation around the bridge piers of bridges in advance and taking countermeasures before the damage becomes apparent.

[0007] Therefore, in order to use the bridge safely for a long period of time without newly replacing the bridge, it is necessary to conduct regular scouring surveys around the bridge piers.

[0008] Among these, as a method for investigating the scouring of bridges, for example, a bridge inspection technique using an underwater drone (see Non-Patent Document 1) has been proposed.

[0009] Here, in the bridge inspection technology using the underwater drone described in Non-Patent Document 1, sonars are attached to the underwater drone in the horizontal and vertical directions, and the shape of the measurement target around the pier is measured by the sonars.

[0010] Also, in the bridge inspection technology using the underwater drone described in Non-Patent Document 1, the underwater drone is horizontally or vertically moved at regular intervals, and measurement data of the measurement target is acquired from the two-dimensional images of the sonars obtained at each position.

[0011] Also, in the bridge inspection technology using the underwater drone described in Non-Patent Document 1, for grasping the position of the underwater drone in water, acoustic positioning methods such as SBL (Short Base Line) and USBL (Ultra Short Base Line) that measure the relative distance and angle from a reference point by sound waves are adopted. Also, the direction of the underwater drone is acquired by an attitude and heading reference system (AHRS) that combines a magnet compass and a gyro sensor.

[0012] Also, as a method for investigating the scour of a bridge, for example, a shape grasping system for underwater structures using an underwater 3D scanner (see Non-Patent Document 2) has been proposed.

[0013] In the shape grasping system for underwater structures using the underwater 3D scanner described in this Non-Patent Document 2, the underwater 3D scanner is suspended about 3 to 10 m away from the pier, and while rotating the sound wave transmitting part, the pier and riverbed shapes are measured as 3D point cloud data.

[0014] Also, in the shape grasping system for underwater structures using the underwater 3D scanner described in Non-Patent Document 2, for one pier, measurements are carried out at about six locations so as to surround it. Then, the noise of the 3D point cloud data is processed, and a plurality of measurement data is integrated to create a 3D model of the pier and the surrounding riverbed, and the 3D model of the pier is overlaid on the design drawing to calculate the scale of the scour.

[0015] In addition, in the underwater structure shape grasping system using an underwater 3D scanner described in Non-Patent Document 2, the above-water part of a pier is measured by a 3D laser scanner to obtain 3D point cloud data with position information in a public coordinate system, and by integrating it with the point cloud data of the underwater part, the polar coordinates of the 3DS are also converted into public coordinates.

Prior Art Documents

Non-Patent Documents

[0016]

Non-Patent Document 1

Non-Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0017] Here, in the bridge inspection technology using an underwater drone described in Non-Patent Document 1, when acquiring the position information of the underwater drone by methods such as USBL or SBL, an error of several percent occurs.

[0018] As a result, there was a problem that the actual position of the underwater drone deviated from the position in the acquired position information by several tens of centimeters or more, and accurate measurement results could not be obtained.

[0019] Also, in the bridge inspection technology using an underwater drone described in Non-Patent Document 1, in the acquisition of azimuth information by AHRS, the magnetic compass was affected by the surrounding magnetism, and there was a problem that the information on the orientation (direction) of the underwater drone could not be accurately acquired.

[0020] Thus, in the bridge inspection technology using an underwater drone described in Non-Patent Document 1, it was difficult to acquire position information and direction information with an accuracy on the order of centimeters, which was originally required, and a more highly accurate and precise investigation could not be performed.

[0021] Also, in the underwater structure shape grasping system using an underwater 3D scanner described in Non-Patent Document 2, since it was necessary to install the underwater 3D scanner in the water and install it at a plurality of locations, it took a great deal of labor and time to measure a single bridge.

[0022] Also, in the underwater structure shape grasping system using an underwater 3D scanner described in Non-Patent Document 2, when creating a 3D model of a pier to be measured, there was an operation of synthesizing data of the underwater 3D scanner and data of an above-water 3D laser scanner at the water surface level, and this data synthesis was also troublesome.

[0023] The present invention was devised in view of the above points, and an object thereof is to provide an underwater survey device that has a simple mechanism and can accurately and efficiently survey the terrain conditions around a structure installed underwater.

Means for Solving the Problems

[0024] In order to achieve the above object, an underwater survey device of the present invention is an underwater survey device for surveying underwater terrain conditions using a predetermined sonar, and includes a first control unit that is installed on the water surface and controls the predetermined sonar, a main body disposed on the water surface, a buoyancy body attached to the main body and floating the main body on the water surface, a driving force generation unit attached to the buoyancy body and generating a driving force for moving or holding the main body floating on the water surface at a fixed point, a second control unit attached to the main body and configured to be able to receive measurement information of the predetermined sonar and transmit and receive information to and from the first control unit, an angle adjustment unit attached to the main body or the second control unit, supporting the predetermined sonar and adjusting the orientation of the predetermined sonar, and a position information acquisition unit that acquires position information and azimuth information of the main body or the predetermined sonar on the water surface.

[0025] Here, the first control unit installed on the water surface can control the oscillation, detection, and measurement of ultrasonic waves by the predetermined sonar. Also, since it is installed on the water surface, for example, it is possible to control the measurement of the predetermined sonar from a position on a bridge or land away from a device such as a bridge or a riverbank above the water surface.

[0026] Further, the main body disposed on the water surface and the buoyancy body attached to the main body and floating the main body on the water surface enable the main body of the underwater survey device to be floated and disposed on the water surface.

[0027] Also, by the driving force generation unit being attached to the buoyancy body and generating a driving force for moving or holding the main body floating on the water surface at a fixed point, the main body of the underwater survey device can be moved to a desired position on the water surface or held at a fixed point at a desired position on the water surface.

[0028] In addition, the second control unit is attached to the main body, receives measurement information of a predetermined sonar, and is configured to be able to transmit and receive information to and from the first control unit. Based on a control signal or the like from the first control unit on the water surface, the second control unit can control the measurement of the predetermined sonar. Further, information on the measurement result of the predetermined sonar can be transmitted to the first control unit, enabling analysis of the measurement result and visualization of the measurement data on the first control unit side.

[0029] In addition, by the position information acquisition unit acquiring the position information and azimuth angle information of the main body or the predetermined sonar on the water surface, it becomes possible to combine the measurement result of the predetermined sonar, the position information of the main body or the predetermined sonar on the water surface, and the azimuth angle information of the main body or the predetermined sonar to obtain information on the underwater terrain or the shape of the structure. That is, it is possible to obtain information indicating the shape of the underwater bridge pier and the terrain of the surrounding river bottom and to grasp the presence or absence of scour holes.

[0030] In addition, the angle adjustment unit is attached to the main body or the second control unit, supports the predetermined sonar, and adjusts the orientation of the predetermined sonar, making it possible to adjust the angle of the ultrasonic wave oscillating from the predetermined sonar. That is, for example, at a position just short of where a bridge is located above the position information acquisition unit, by adjusting the orientation of the predetermined sonar, it becomes possible to obtain the measurement result of the predetermined sonar at a position where the acquisition of the position information at the position information acquisition unit is ensured. According to this, it becomes easier for the position information acquisition unit to acquire more accurate position information. Also, the measurement result of the sonar can be combined with accurate position information, making it easier to obtain more accurate terrain information underwater.

[0031] Further, when the angle adjustment unit has an X-axis rotation unit that adjusts the orientation of a predetermined sonar with the X-axis as the rotation axis with respect to the X-axis and the Y-axis that forms an angle with the X-axis and is located on an arbitrary plane, and a Y-axis rotation unit that adjusts the orientation of the predetermined sonar with the Y-axis as the rotation axis, the orientation of the predetermined sonar can be adjusted with each of the two axes of the X-axis and the Y-axis as the axis of rotation. As a result, it becomes possible to adjust the angle of the ultrasonic wave oscillated from the predetermined sonar with higher degrees of freedom, and it becomes easier to widely cope with differences in the shapes of bridges and bridge piers, or the shapes of river channels and riverbed terrains.

[0032] Further, when an arbitrary plane is parallel to the horizontal plane and the X-axis and the Y-axis are orthogonal to each other in the initial state where the orientation of the predetermined sonar is directed vertically downward, the orientation of the predetermined sonar can be adjusted with each of the X-axis parallel to the horizontal plane and the Y-axis having an angle different from the X-axis by 90 degrees as the axis of rotation. That is, for example, by forming a part of the frame-shaped main body parallel to the X-axis or the Y-axis, it becomes easier to grasp on which side to rotate the predetermined sonar when looking at the main body from above the water, and the operability and the efficiency of measurement by the sonar can be improved.

[0033] In addition, when the position information acquisition unit includes two antennas for receiving satellite signals from a plurality of positioning satellites, a communication device for receiving correction data generated based on satellite signals received by a predetermined reference station from the plurality of positioning satellites, and a receiver that calculates the position coordinates of at least one of the two antennas and the azimuth angle of the main body based on the satellite signals received by the two antennas and the correction data received by the communication device, so-called Moving Base mode RTK (Real Time Kinematic)-GNSS (Global Navigation Satellite System) positioning enables accurate acquisition of the position information of the main body or a predetermined sonar with centimeter-order accuracy and the information on the azimuth of the main body or the predetermined sonar. As a result, it is possible to investigate the accurate position information of the scoured portion of the riverbed. In the positioning method of this position information acquisition unit, correction data is wirelessly transmitted from a predetermined reference station (GNSS reference station) installed at a point with known position coordinates (known point), and the correction data is received by a wireless device on the main body side. The receiver on the main body side (GNSS receiver) calculates the relative position from the predetermined reference station and, combined with the coordinates of the known point, obtains the coordinates of the main body or a predetermined sonar with high accuracy. Also, the receiver on the main body side can accurately measure the azimuth angle of the main body or a predetermined sonar from the information on the position coordinates of the antenna. Thus, by adopting the Moving Base mode RTK-GNSS positioning in the position information acquisition unit, it becomes possible to measure the accurate position information and azimuth information of the main body of the underwater survey device or a predetermined sonar and combine them with the measurement information of the predetermined sonar. Here, the "correction data generated based on satellite signals received by a predetermined reference station from a plurality of positioning satellites" means data obtained by the Ntrip (Networked Transport of RTCM via Internet Protocol) method via the Internet, and data including correction data generated based on satellite signals received by a reference station with a base as the coordinate position in the geodetic coordinate system and provided with the reference station.

[0034] Also, when the first control unit and the second control unit are connected by a cable, more stable transmission and reception of information can be achieved between the first control unit and the second control unit via the cable. Further, the main body can be suspended by the cable, and when the main body is arranged on the water surface side from a bridge, a riverbank, etc., it becomes easier to manually arrange the main body at an arbitrary position on the water using the cable. Also, when recovering the main body from the water surface side, the main body can be pulled up by the cable, and the recovery operation can be easily performed.

[0035] Also, when a predetermined sonar is an imaging sonar that emits fan-shaped ultrasonic waves, the measurement process by the sonar is relatively fast compared to other types of sonars, and accurate measurement data can be obtained even if the sonar moves slightly. Further, by directing the imaging sonar vertically downward or horizontally, information on the shape of a vertical cross-section in water and the shape of a horizontal cross-section (spread) in a plan view of the water can be acquired.

[0036] Also, when the second control unit has an angle sensor that detects the inclination of the main body, even if the main body sways on the water due to the influence of water flow or wind, based on the measurement information of the angle sensor, the driving force generation unit can be controlled to easily maintain the orientation of the main body so that the orientation of the main body faces a certain direction. As a result, it becomes easier to accurately obtain the position information and azimuth angle information of the main body or a predetermined sonar.

Advantages of the Invention

[0037] The underwater survey device according to the present invention has a simple mechanism and can accurately and efficiently survey the terrain conditions around a structure installed underwater.

Brief Description of the Drawings

[0038]

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Embodiments for Carrying Out the Invention

[0039] Hereinafter, embodiments of the present invention will be described with reference to the drawings to facilitate understanding of the present invention. Note that the following content is an example of an inspection method and an example of an inspection mechanism to which the present invention is applied, and the content of the present invention is not limited thereto, and can be appropriately set and changed.

[0040] In the following description, based on FIG. 3(b), the left side in the figure is referred to as "front or forward", and the right side in the figure is referred to as "rear or backward". Also, based on FIG. 3(b), the upper side in the figure is referred to as "up or upward", and the lower side in the figure is referred to as "down or downward".

[0041] Also, based on FIG. 3(b), the direction connecting the left and right directions of the paper surface is referred to as "front-rear direction or X-axis direction", and the direction connecting the front side and the back side of the paper surface is referred to as "left-right direction or Y-axis direction". Also, based on FIG. 3(b), the direction connecting the up and down directions of the paper surface is referred to as "up-down direction or vertical direction".

[0042] Also, based on FIG. 8, the range above the water surface is referred to as "above water", and the range below the water surface is referred to as "under water".

[0043] An underwater survey device A, which is an example of an underwater survey device to which the present invention is applied, is a device for measuring the shape of a bridge pier in water and the shape of the riverbed topography in a river or the like using a sonar, and for investigating the scouring situation and the like.

[0044] As shown in FIG. 1, the underwater survey device A includes a control mechanism 1, a main body device unit 2, and a tether cable 3.

[0045] Here, the control mechanism 1 is a part that controls measurement, driving, etc. by the main body device unit 2, and is a part arranged on the ground G such as above a bridge or on a riverbank. That is, an operator can perform measurement, movement operation, analysis of measurement results, etc. in the main body device unit 2 via the control mechanism 1.

[0046] In addition, the main body device unit 2 is a part arranged on the water surface of a river or the like, moves on the water surface, and measures the shape of the underwater terrain or the like via a sonar at each position.

[0047] In addition, the tether cable 3 is a communication connection member that connects the control mechanism 1 and the main body device unit 2 and enables transmission and reception of information. Note that the tether cable 3 mentioned here is a member corresponding to the cable in the claims of the present application.

[0048] As shown in FIG. 1, the control mechanism 1 includes a measurement control device 10, a communication device 11, and an Internet router 12.

[0049] In addition, the measurement control device 10 is a device responsible for controlling measurement, driving, etc. by the main body device unit 2. Note that the measurement control device 10 mentioned here corresponds to the first control unit in the claims of the present application.

[0050] Via this measurement control device 10, control of the direction of the imaging sonar 21 by the gimbal device 22 described later, control of the movement of the moving device main body 20, image display of sonar measurement data, recording of measurement data, and recording of the position information of the imaging sonar 21 are performed.

[0051] In addition, the communication device 11 is a device that enables transmission and reception of information between the measurement control device 10 and the main body side control device 25 described later via the tether cable 3.

[0052] In addition, the Internet router 12 is a member that connects the measurement control device 10 and the main body side control device 25 to the Internet line.

[0053] In addition, the Internet router 12 is a communication means for acquiring GNSS correction data (RTK correction signal) in the Moving Base method RTK-GNSS positioning by a position information acquisition mechanism described later, in the Ntrip (Networked Transport of RTCM via Internet Protocol) method via the Internet. Note that the GNSS correction data (RTK correction signal) referred to here corresponds to the correction data generated based on the satellite signals received by a plurality of positioning satellites by a predetermined reference station in the claims of the present application.

[0054] Here, it is not necessarily required to provide the tether cable 3 connecting the control mechanism 1 and the main body device unit 2, and it is also possible to adopt a mode in which the control mechanism 1 and the main body device unit 2 are connected by wireless communication. However, since stable information transmission and reception are possible, and the operation of arranging the main body device unit 2 on the water surface and the operation of pulling it up from the water surface are facilitated, it is preferable to provide the tether cable 3 connecting the control mechanism 1 and the main body device unit 2.

[0055] As shown in FIG. 1, the main body device unit 2 includes a moving device main body 20, an imaging sonar 21, and a gimbal device 22.

[0056] In addition, the moving device main body 20 includes a position information acquisition mechanism 23, a moving mechanism 24, and a main body side control device 25.

[0057] In addition, the imaging sonar 21 is a device that oscillates fan-shaped ultrasonic waves in water, receives the reflected ultrasonic waves, and measures the shape of underwater structures and terrain. Using the imaging sonar 21, the direction, distance, and dimensions of an object can be measured.

[0058] In addition, the gimbal device 22 is a device member that adjusts the orientation of the imaging sonar 21. That is, the gimbal device 22 is a member that adjusts the direction of the ultrasonic waves oscillated by the imaging sonar 21. Note that the gimbal device 22 referred to here corresponds to the angle adjustment unit in the claims of the present application.

[0059] In addition, the position information acquisition mechanism 23 is a part that acquires the position information and azimuth angle information of the imaging sonar 21. Note that the position information acquisition mechanism 23 referred to here corresponds to the position information acquisition unit in the claims of the present application.

[0060] Here, the position information acquisition mechanism 23 may be configured to acquire the position information and azimuth angle information of the mobile device main body 20, and calculate the position information and azimuth angle information of the imaging sonar 21 based on this information.

[0061] In addition, the movement mechanism 24 is a part responsible for the movement of the mobile device main body 20 on the water surface or the fixed-point holding at an arbitrary position on the water surface.

[0062] [Position Information Acquisition Mechanism] As shown in FIG. 1, the position information acquisition mechanism 23 includes a GNSS antenna 230, a GNSS antenna 231, a GNSS receiver 232, a GNSS receiver 233, a controller 234, and a communication device 235.

[0063] This position information acquisition mechanism 23 is a mechanism that measures the position information and azimuth angle information of the imaging sonar 21 by means of Moving Base method RTK-GNSS positioning. In the underwater survey device A, by combining the position information and azimuth angle information of the imaging sonar 21 measured by the position information acquisition mechanism 23 with the measurement results of the imaging sonar 21, the accurate positions of the terrain and the like measured by the sonar can be grasped. Here, RTK is an abbreviation for Real Time Kinematic, and GNSS is an abbreviation for Global Navigation Satellite System.

[0064] In addition, the two GNSS antennas 230 and GNSS antenna 231 are antennas for receiving satellite signals from a plurality of positioning satellites (GNSS satellites). Note that the GNSS antennas 230 and GNSS antenna 231 referred to here correspond to the two antennas in the claims of the present application.

[0065] In addition, the communication device 235 is a device that enables the transmission and reception of information with the communication device 11 via the tether cable 3. Further, the communication device 235 is a device that receives GNSS correction data (RTK correction signal) in the Ntrip method via the Internet router 12. Here, the communication device 235 corresponds to the communication machine in the claims of the present application.

[0066] In addition, the GNSS receivers 232 and 233 are receivers that calculate the position coordinates in the geographical coordinate system (global coordinate system) of the two GNSS antennas 230 and 231, and the azimuth angle of the imaging sonar 21, based on the satellite signals received by the two GNSS antennas 230 and 231 and the GNSS correction data (RTK correction signal) received by the radio of the communication device 235. Here, the GNSS receivers 232 and 233 correspond to the receivers in the claims of the present application.

[0067] In addition, the GNSS receivers 232 and 233 are also parts that calculate the position coordinates of the imaging sonar 21 in the geographical coordinate system based on the position coordinates of the two GNSS antennas 230 and 231 in the geographical coordinate system. The position coordinates of the imaging sonar 21 in the geographical coordinate system become the position information of the imaging sonar 21.

[0068] In addition, the GNSS receivers 232 and 233 are configured to calculate the azimuth angle information of the imaging sonar 21 from the line connecting the position coordinates of the GNSS antenna 230 attached to the front of the main body 200, which will be described later, and the position coordinates of the GNSS antenna 231 attached to the rear of the main body 200.

[0069] Further, the controller 234 is a member that controls the following based on the control signal from the measurement control device 10. That is, the controller 234 is a member that controls the angle adjustment of the imaging sonar 21 by the gimbal device 22, the arithmetic processing by the GNSS receivers 232 and 233, and the ESC (Electric Speed Controller) 241 that constitutes the moving mechanism 24.

[0070] Here, it is not necessarily required to provide the GNSS receivers 232 and 233 at two locations in the position information acquisition mechanism 23, and it is also possible to adopt a structure in which the GNSS receivers 232 and 233 are integrated.

[0071] [Structure of the Mobile Device Main Body] As shown in FIG. 2, the mobile device main body 20 has a frame-shaped main body 200 and a buoyancy body 201. Further, a main body control device 25 and a plurality of thrusters 241 that constitute the moving mechanism 24 are attached to the main body 200.

[0072] Further, the main body 200 is a frame-shaped base for attaching each member that constitutes the mobile device main body 20. Here, the main body 200 corresponds to the main body in the claims of the present application.

[0073] Further, the buoyancy body 201 is a container body that houses air inside, and is a member that imparts buoyancy to float the main body 200 on the water surface. Two buoyancy bodies 201 are attached to the main body 200 (see FIGS. 2 and 3(a)). Here, the buoyancy body 201 corresponds to the buoyancy body in the claims of the present application.

[0074] Further, the main body side control device 25 is composed of a GNSS receiver 232, a GNSS receiver 233, a controller 234, a communication device 235, and an ESC 241 (see FIG. 1). Further, a tether cable 3 is connected to the main body side control device 25 (see FIG. 2). Here, the main body side control device 25 corresponds to the second control unit in the claims of the present application.

[0075] Further, the main body side control device 25 is attached above the position where the buoyancy body 201 of the main body 200 is attached in the vertical direction, and is provided so as to be positioned above the water surface (see FIGS. 3(a) and 3(b)).

[0076] In addition, a GNSS antenna 230 is attached to the upper part of the front side of the main body 200. Also, a GNSS antenna 231 is attached to the upper part of the rear side of the main body 200 (see FIGS. 2 and 3(b)).

[0077] Also, a gimbal device 22 and an imaging sonar 21 are attached to the bottom side of the main body 200 via the main body side control device 25 (see FIGS. 3(a), 3(b) and 4).

[0078] Here, the shape of the main body 200 is not particularly limited, and it is possible to appropriately design the shape as long as the buoyancy body 201, the main body side control device 25, the gimbal device 22 and the imaging sonar 21 can be attached and the buoyancy body 201 can float on the water surface.

[0079] Also, it is not necessarily required that the GNSS antenna 230 is attached to the upper part of the front side of the main body 200 and the GNSS antenna 231 is attached to the upper part of the rear side of the main body 200. It is sufficient that the two GNSS antennas are arranged at a distance from each other at any location on the main body 200. However, when viewed from the imaging sonar 21, by arranging the two GNSS antennas in the front-rear direction, the line connecting the position coordinates of each GNSS antenna becomes information indicating the azimuth angle of the imaging sonar 21, and if the position coordinates of the two GNSS antennas can be obtained, it becomes possible to easily calculate the azimuth angle information. Also, for example, when viewed from the imaging sonar 21, when the two GNSS antennas are arranged in the left-right direction, the line perpendicular to the line connecting the position coordinates of the left and right GNSS antennas respectively becomes information indicating the azimuth angle of the imaging sonar 21.

[0080] [Moving mechanism] As shown in FIG. 1, the movement mechanism 24 has a plurality of thrusters 240 and an ESC 241 corresponding to each thruster.

[0081] Further, the thruster 240 is a propulsion device that generates a driving force for moving the moving device main body 20 on the water surface. The ESC 241 is a member that controls the output of the thruster 240, the rotation direction, and the rotation speed of the propeller constituting the thruster 240 based on control signals from the measurement and control device 10 and the controller 234.

[0082] More specifically, as shown in FIGS. 4 and 5, four thrusters 240 are attached further below the buoyancy body 201 on the bottom surface side of the main body 200. Further, the thruster 240 is fixed to the main body 200 in a direction inclined 45° with respect to an axis parallel to the Y-axis direction.

[0083] Each thruster 240 rotates the propeller in the forward or reverse direction using a motor (not shown) as a drive source to generate a driving force in water. Also, one ESC 241 is configured to control one thruster 240.

[0084] Based on the control signal, the four ESC 241s control the output of the thruster 240 under their control and the rotation direction of its propeller, and by changing the direction of the thrust vector that is the resultant force of the output vectors of the four thrusters 240, the main body 200 can be moved in a desired direction.

[0085] For example, in the example shown in FIG. 5, the two thrusters 240 on the left side in the figure generate output vectors in the direction of the arrow indicated by the symbol F1, and the two thrusters 240 on the right side in the figure generate output vectors in the direction of the arrow indicated by the symbol F2. As a result, the resultant force of the four output vectors is generated in the direction of the arrow indicated by the symbol F3, and the main body 200 moves to the right side in the figure (the direction of the arrow of the symbol F3).

[0086] Here, it is not necessarily the case that the movement mechanism 24 is composed of a thruster 240 fixed to the main body 200 and an ESC 241 that controls the thruster 240. For example, it is also possible to rotatably attach a thruster to the main body 200 and control the direction of rotation and output of the thruster. However, from the perspective of being able to move the main body in a desired direction with a simpler structure, it is preferable that the movement mechanism 24 is composed of a thruster 240 fixed to the main body 200 and an ESC 241 that controls the thruster 240.

[0087] [Gimbal device] As shown in FIGS. 3 and 4, the gimbal device 22 is attached to the lower part of the main body side control device 25. Further, the gimbal device 22 supports the imaging sonar 21.

[0088] This gimbal device 22 has a mounting flange 220, an arm base 221, a first arm 222, and a second arm 223 (see FIG. 6).

[0089] Also, the mounting flange 220 is a member for attaching the gimbal device 22 to the lower part of the main body side control device 25. The arm base 221 is a part whose upper end is fixed to the mounting flange and rotatably supports the second arm 223.

[0090] Also, the first arm 222 is a member for attaching the imaging sonar 21, and both ends thereof are rotatably supported by the second arm 223. The second arm 223 is a member that connects the first arm 222 and the arm base 221.

[0091] Also, the first arm 222 is a member that rotates the direction of the imaging sonar 21 around a rotation axis parallel to the X-axis direction in an initial state where the direction of the imaging sonar 21 is directed vertically downward.

[0092] The end of this first arm 222 is attached to an underwater servo 224 (see FIGS. 6 and 7(a)), is rotatably supported by the second arm 223, and can adjust the direction of the imaging sonar 21.

[0093] When the imaging sonar 21 is rotated via the first arm 222, the inclination can be adjusted within a range of 90 degrees from the direction (0 degrees) in which the tip (ultrasonic oscillation unit) of the imaging sonar 21 faces vertically downward in FIG. 7(b) to the direction facing the left side in FIG. 7(b) or the direction facing the right side in FIG. 7(b).

[0094] Further, the second arm 223 is a member that rotates the orientation of the imaging sonar 21 about a rotation axis parallel to the Y-axis direction. Also, in a state where the imaging sonar 21 is directed vertically downward (initial state), the rotation axis of the first arm 222 and the rotation axis of the second arm 223 are located on a plane substantially parallel to the horizontal plane and are in a perpendicular positional relationship with each other.

[0095] The end of this second arm 223 is attached to the underwater servo 225 (see FIG. 7(b)), pivotally supported by the arm base 221, and can be rotated to adjust the orientation of the imaging sonar 21 attached to the first arm 222.

[0096] When the imaging sonar 21 is rotated via the second arm 223, the inclination of the imaging sonar 21 can be adjusted by rotating in the clockwise direction in FIG. 7(a) from the direction in which the tip (ultrasonic oscillation unit) of the imaging sonar 21 faces vertically downward in FIG. 7(a).

[0097] Also, the rotation range via the second arm 223 is configured to be rotatable within a range from 0 degrees with the direction in which the longitudinal direction of the second arm 223 and the X-axis direction are parallel as 0 degrees to a range where the angle formed by the X-axis direction and the longitudinal direction of the second arm 223 is 30 degrees.

[0098] Also, the rotation angles of the first arm 222 and the second arm 223 by the underwater servo 224 and the underwater servo 225 are configured to be controllable via the controller 234 based on a control signal from the measurement control device 10.

[0099] Also, as shown in FIG. 6, it is also possible to adjust the orientation of the imaging sonar 21 by tilting each of the first arm 222 and the second arm 223.

[0100] Here, it is not necessarily the case that the gimbal device 22 is configured to include the mounting flange 220, the arm base 221, the first arm 222, and the second arm 223. As long as the orientation of the tip of the imaging sonar 21 can be adjusted, the structure of the angle adjustment mechanism can be set as appropriate.

[0101] Also, it is not necessarily the case that the gimbal device 22 has a structure in which the angles can be adjusted by two rotation axes, namely, the rotation axis of the first arm 222 and the rotation axis of the second arm 223. For example, it may be an aspect in which there is one rotation axis for adjusting the orientation of the imaging sonar 21, or an aspect in which three or more rotation axes are provided.

[0102] Also, it is not necessarily the case that in a state where the imaging sonar 21 is directed vertically downward (initial state), the rotation axis of the first arm 222 and the rotation axis of the second arm 223 are located on a plane substantially parallel to the horizontal plane and are in a perpendicular positional relationship with each other. For example, it may be an aspect in which each rotation axis is not located on a plane substantially parallel to the horizontal plane, or a positional relationship in which the rotation axes are not perpendicular to each other and form an angle different from 90 degrees. However, by forming a part of the main body 200 parallel to the X axis or the Y axis, it becomes easier to grasp which side to rotate the imaging sonar 21 when viewing the main body 200 from above the water, and from the viewpoint of improving the operability and the efficiency of measurement by the sonar, it is preferable that in a state where the imaging sonar 21 is directed vertically downward (initial state), the rotation axis of the first arm 222 and the rotation axis of the second arm 223 are located on a plane substantially parallel to the horizontal plane and are in a perpendicular positional relationship with each other.

[0103] Also, it is not necessarily the case that the rotation range of the imaging sonar 21 via the first arm 222 is limited within a range of 90 degrees from vertically downward (0 degrees) to the left or right direction. For example, it is also possible to adopt an aspect in which the tip of the imaging sonar 21 can be adjusted to an angle such that it tilts obliquely upward beyond 90 degrees in the left and right directions.

[0104] Also, necessarily, the rotation range of the imaging sonar 21 via the second arm 223 is not necessarily limited to the range where the angle formed by the longitudinal direction of the second arm 223 and the X-axis direction is 0 degrees, and the angle formed by the X-axis direction and the longitudinal direction of the second arm 223 is 30 degrees starting from this 0 degree. For example, it is also possible to adopt a mode in which the angle can be adjusted within the range where the angle formed by the X-axis direction and the longitudinal direction of the second arm 223 is 90 degrees starting from 0 degree.

[0105] [Imaging Sonar] The imaging sonar 21 is a sonar capable of oscillating fan-shaped ultrasonic waves, and is configured such that the swath angle is within the range of 70 degrees or more and 130 degrees, and the beam width is adjustable within the range of 12 degrees or more and 20 degrees or less. Also, the imaging sonar 21 can be set within the range where the maximum range of the ultrasonic wave is 40 m or more and 120 m or less.

[0106] In FIG. 7(a), the irradiation range of the ultrasonic wave when the swath angle is set to 130 degrees with the tip of the imaging sonar 21 directed vertically downward is shown. Also, in FIG. 7(b), the irradiation range of the ultrasonic wave when the beam width is set to 20 degrees with the tip of the imaging sonar 21 directed vertically downward is shown.

[0107] Here, necessarily, it is not necessary to adopt the imaging sonar 21 as the sonar member of the underwater survey device A. For example, it is also possible to adopt a multi-beam sonar. However, since it is relatively low in price compared to the multi-beam sonar, has a relatively high scan speed, and the measurement result is less affected by the fluctuations during measurement, it is preferable to adopt the imaging sonar 21.

[0108] Also, the swath angle, beam width, and maximum range of the ultrasonic wave of the imaging sonar 21 are not particularly specified, and can be appropriately selected.

[0109] In addition, in the underwater survey device to which the present invention is applied, an image of the measurement result of the sonar can be identified by AI, and the presence or absence of scouring can be automatically determined. As a result, it is possible to confirm the presence or absence of scouring in a river or the like based on an objective evaluation without being affected by the subjectivity of the operator.

[0110] In addition, in the underwater survey device to which the present invention is applied, a LiDAR (Light Detection and Ranging) sensor that irradiates a target with laser light and analyzes the reflected light to measure the distance and shape to the object can also be used in combination to complement the position information.

[0111] In this case, by mounting a LiDAR sensor on the mobile device main body 20 and using its measurement image, for example, the positional relationship between the mobile device main body 20 and the pier of the survey target can be clarified, and more accurate measurement results can be obtained.

[0112] In the underwater survey device A, which is an example of the underwater survey device to which the present invention is applied, the shape of the underwater pier portion of the bridge installed in the river and the terrain of the riverbed around the pier can be measured by the imaging sonar 21 at a desired position in the river. Further, by combining the accurate position information and azimuth information of the imaging sonar 21 measured by the position information acquisition mechanism 23 with the measurement result of the sonar, the accurate position of the measurement location can be obtained. As a result, it is possible to accurately investigate the scouring situation of the riverbed by analyzing the measurement results at each measurement position or generating two-dimensional data of the terrain by summarizing a plurality of measurement results.

[0113] For example, as shown in the image diagram of the survey in FIG. 8, while moving the mobile device main body 20 floating on the water surface W of the river, the mobile device main body 20 is held at a fixed point at a desired position, and measurement is performed with the imaging sonar 21.

[0114] In addition, when the imaging sonar 21 performs measurement with its tip directed vertically downward, information on the shape of the vertical cross section can be obtained, and when the measurement is performed with the tip directed horizontally, information on the shape of the horizontal cross section viewed in plan of the water surface can be obtained.

[0115] Further, as shown in FIG. 8, with respect to the structure in which the bridge B projects, by adjusting the inclination of the imaging sonar 21 with the gimbal device 22, measurement by the sonar can be performed at a position where the upper part of the mobile device main body 20 is not covered by the bridge B.

[0116] That is, in the position information acquisition mechanism 23, since satellite signals from a plurality of positioning satellites (GNSS satellites) are used, if there are structures such as bridges above the GNSS antenna 230 and the GNSS antenna 231, the acquisition accuracy of the satellite signals will be affected, and accurate calculation of position coordinates and the like will not be possible.

[0117] Here, in the underwater survey device A, since the gimbal device 22 can adjust the orientation of the imaging sonar 21 to adjust the direction of the ultrasonic waves oscillated by the sonar, measurement by the imaging sonar 21 is possible at a position where the upper parts of the GNSS antenna 230 and the GNSS antenna 231 are not covered by structures. As a result, the position information of the imaging sonar 21 can be accurately acquired and reflected in the measurement results of the sonar.

[0118] In the case of FIG. 8, as a result of performing measurements at a plurality of positions while adjusting the orientation of the imaging sonar 21, the vertical cross-sectional shape Z1 corresponding to the P1 part of the pier and the vertical cross-sectional shape Z2 corresponding to the P2 part of the pier can be confirmed from the measurement results of the sonar and the position information. Similarly, the shape of the flat part R1 of the riverbed, the shape of the flat part R3 of the pier, and the shape of the scouring R2 occurring in the riverbed around the P2 part of the pier can be confirmed.

[0119] In this way, although the underwater survey device A has a simple structure, in combination with the accurate position information of the imaging sonar 21, the measurement results of the imaging sonar 21 can be obtained, and an accurate investigation of the scouring situation can be performed.

[0120] Further, the underwater survey device A can move to a desired position in the river or hold a fixed point via the moving mechanism 23, and can efficiently perform measurement by the imaging sonar 21.

[0121] As described above, the underwater survey device of the present invention has a simple mechanism and can accurately and efficiently survey the terrain around a structure installed underwater.

[0122] [Embodiment] Hereinafter, an example of a survey using the above-described underwater survey device A will be described.

[0123] [Measurement in a test water tank] The shape of the block 101 submerged on the bottom of the test water tank 100 shown in FIG. 9 was measured using the underwater survey device A. The test water tank 100 has an outer wall portion 102. The test water tank 100 has a storage space 103, and water is stored in this storage space 103 to submerge the block 101.

[0124] The block 101 has dimensions of length 390 mm, width 190 mm, and height 150 mm. In FIG. 9, the display of the water stored in the storage space 103 is omitted.

[0125] In this measurement, first, in the measurement situation shown in FIG. 10, the underwater survey device A was placed on the water surface W of the test water tank 100, and the vertical cross-sectional shape was measured with the imaging sonar 21 from directly above the block 101. The swath angle of the imaging sonar 21 was set to 130 degrees. In FIG. 10, the measurement range of the imaging sonar 21 is indicated by the reference R, and the description of the underwater survey device A is omitted.

[0126] In FIG. 11, an image diagram of the measurement result of the imaging sonar 21 measured in the measurement situation shown in FIG. 10 is shown.

[0127] As shown in FIG. 11, in the image diagram, the shape of the block 101 at the bottom of the test water tank 100 was confirmed. Also, the dimension of the length 390 mm (0.39 m) of the block 101 could be measured. In FIG. 11, the shape of the outer wall 102 of the test water tank 100 was also confirmed.

[0128] In this measurement, the underwater survey device A was placed on the water surface W of the test water tank 100 in the measurement situation shown in FIG. 12, and the vertical cross-sectional shape was measured with the imaging sonar 21 from directly above the block 101. Also, the swath angle of the imaging sonar 21 was set to 130 degrees. FIG. 12 also shows the measurement range of the imaging sonar 21 with the symbol R, and the description of the underwater survey device A is omitted.

[0129] In FIG. 13, an image diagram of the measurement result of the imaging sonar 21 measured in the measurement situation shown in FIG. 12 is shown.

[0130] As shown in FIG. 13, in the image diagram, the shape of the block 101 at the bottom of the test water tank 100 was confirmed. Also, the dimension of the height 150 mm (0.15 m) of the block 101 could be measured.

[0131] [Measurement around the bridge pier in the river] Subsequently, an example of investigating the structure around the underwater bridge pier using the underwater survey device A in a river is shown.

[0132] As shown in FIG. 14, the moving device main body 20 was floated on the water surface of the river, and the area around the bridge pier P was measured. The portion indicated by the symbol L in FIG. 14 shows the shape image of the bottom. Also, FIGS. 15 to 17 show the image diagrams of the respective measurement results of the imaging sonar 21.

[0133] First, FIG. 15 shows an image diagram of the measurement result obtained by measuring the imaging sonar 21 vertically downward with the underwater survey device A. In this measurement, only the line indicating the shape of the bottom R was confirmed, and the bridge pier P was not confirmed. In the image diagrams of FIGS. 15 and 16, the view is from the side of the moving device main body 20 looking at the side indicated by the symbol L in FIG. 14. The position of the bridge pier P in FIG. 14 (the left side in the figure) and the position of the bridge pier P in FIGS. 15 to 16 (which will be located on the right side in the figure) have a composition where they are located on the opposite sides left and right.

[0134] Therefore, the measurement was carried out by tilting the direction of the imaging sonar 21 by 30 degrees from vertically downward to the horizontal direction via the first arm 222 of the gimbal device 22. The measurement results are shown in Fig. 16.

[0135] By tilting the direction of the imaging sonar 21 via the first arm 222, the angle at which the ultrasonic wave is oscillated changes. As shown in Fig. 16, in the image diagram of the measurement results, in addition to the line showing the shape of the water bottom R, the line showing the shape of the pier P could be confirmed.

[0136] Also, Fig. 17 shows the results of measurement with the imaging sonar 21 directed horizontally. As shown in Fig. 17, in the cross-sectional shape in the horizontal direction,

Explanation of Signs

[0137] A Underwater survey device 1 Control mechanism 10 Measurement control device 11 Communication device 12 Internet router 2 Main body device section 20 Mobile device main body 200 Main body 201 Buoyancy body 21 Imaging sonar 22 Gimbal device 220 Mounting flange 221 Arm base 222 First arm 223 Second arm 224 Underwater servo 225 Underwater servo 23 Position information acquisition mechanism 230 GNSS antenna 231 GNSS antenna 232 GNSS receiver 233 GNSS receiver 234 Controller 235 Communication device 24 Moving mechanism 240 Thruster 241 ESC 25 Body-side control device 3 Tether cable 100 Test water tank 101 Block 102 Outer wall part 103 Accommodation space< / url:>

Claims

1. An underwater survey device for surveying the underwater terrain using a predetermined sonar, comprising: a first control unit installed on the water surface for controlling the predetermined sonar; a main body disposed on the water surface; a buoyancy body attached to the main body for floating the main body on the water surface; a driving force generating unit attached to the buoyancy body for generating a driving force to move or hold the main body floating on the water surface at a fixed point; a second control unit attached to the main body, configured to receive measurement information of the predetermined sonar and to be able to transmit and receive information to and from the first control unit; an angle adjustment unit attached to the main body or the second control unit for supporting the predetermined sonar and adjusting the orientation of the predetermined sonar; a position information acquisition unit for acquiring position information and azimuth information of the main body or the predetermined sonar on the water surface, wherein the position information acquisition unit comprises two antennas for receiving satellite signals from a plurality of positioning satellites, a communication device for receiving correction data generated by a predetermined reference station based on satellite signals received from the plurality of positioning satellites, and a receiver for calculating the position coordinates of at least one of the two antennas and the azimuth of the main body based on the satellite signals received by the two antennas and the correction data received by the communication device. An underwater survey device.

2. The angle adjustment unit comprises an X-axis rotation unit for adjusting the orientation of the predetermined sonar with the X-axis as the rotation axis, and a Y-axis rotation unit for adjusting the orientation of the predetermined sonar with the Y-axis as the rotation axis, with respect to an X-axis and a Y-axis which are respectively located on an arbitrary plane and form an angle with the X-axis. The underwater survey device according to claim 1.

3. The arbitrary plane is parallel to the horizontal plane, and in an initial state where the orientation of the predetermined sonar is directed vertically downward, the X-axis and the Y-axis are in a perpendicular relationship. The underwater survey device according to claim 2.

4. The underwater survey device according to claim 1 or claim 2, wherein the first control unit and the second control unit are connected by a cable.

5. The underwater survey device according to claim 1 or claim 2, wherein the predetermined sonar is an imaging sonar that emits fan-shaped ultrasonic waves.

6. The underwater survey device according to claim 1 or claim 2, wherein the second control unit has an angle sensor for detecting the inclination of the main body. ​ ​ ​ ​ ​

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