JP2024118519A - Expandable underwater vehicle-surface repeater connection system and method for operating the expandable underwater vehicle-surface repeater connection system - Google Patents

Abstract

[Problem] In a system in which an underwater vehicle and a surface repeater are connected by an information transmission line, an expandable underwater vehicle-surface repeater connection system is provided that can avoid problems such as the information transmission line getting caught when using the underwater vehicle to inspect an object to be inspected.
[Solution] The system comprises a first underwater vehicle 100, a second underwater vehicle 102, and a surface repeater 200, and image information captured by an imaging means is transmitted from the second underwater vehicle 102 to the first underwater vehicle 100 via underwater optical communication, and image information received by the first underwater vehicle 100 is transmitted to the surface repeater 200 via an information transmission line 24 connecting the first underwater vehicle 100 and the surface repeater 200, so that the first underwater vehicle 100 tracks the second underwater vehicle 102, and instructions are transmitted to the second underwater vehicle 102 via the surface repeater 200, the information transmission line 24, and the first underwater vehicle 100.
[Selected Figure] Figure 1

Description

The present invention relates to an underwater vehicle-surface repeater connection system that connects an expandable underwater vehicle and a surface repeater, and a method for operating the same.

In recent years, coastal use such as offshore wind power generation has been attracting attention as a source of natural energy supply. Accordingly, the need for underwater facility inspection is also increasing. Therefore, there is a need for technology to control the position of underwater vehicles traveling underwater and the cables connected to the underwater vehicles with high precision.

An underwater vehicle-surface repeater connection system is disclosed, which includes an information transmission line that connects the surface repeater and the underwater vehicle with a cable and transmits acquired information, including image information obtained by the underwater vehicle, and a position setting means that sets a target latitude and target longitude for the surface repeater and the underwater vehicle. The repeater propulsion means is driven based on the set target latitude and target longitude and the surface position measured by the repeater position measurement means, and the position of the underwater vehicle is controlled based on the set target latitude and target longitude and the underwater position estimated by the vehicle position estimation means, so that the underwater vehicle and the surface repeater run side by side while maintaining their vertical positional relationship on the water surface and underwater up to the target latitude and target longitude. (Patent Document 1)

On the other hand, an optical communication system has been disclosed that uses visible light to exchange information between an underwater vehicle and an observation device installed on the seabed, etc. (Patent Document 2)

An underwater visible light communication system has also been disclosed that uses multiple wavelengths of visible light, changes the wavelength of the visible light depending on the water quality conditions, and ensures communication while also extending the battery operating time. (Patent Document 3)

JP 2022-145659 A International Publication No. 2021/152679 JP 2009-278455 A

However, with conventional underwater vehicle-surface repeater connection systems, when inspecting underwater structures with mooring lines or complex structures, such as floating offshore wind power generation facilities, there is a risk of problems occurring, such as the cable connecting the surface repeater and the underwater vehicle getting caught on the mooring line or structure. Therefore, there is a need for an underwater vehicle-surface repeater connection system and its operating method that can avoid such problems.

The present invention aims to provide an expandable underwater vehicle-surface repeater connection system and its operating method that can avoid problems with the information transmission line getting caught when inspecting an object using the underwater vehicle in a system in which the underwater vehicle and the surface repeater are connected by an information transmission line.

The expandable underwater vehicle-surface repeater connection system corresponding to claim 1 is an underwater vehicle-surface repeater connection system having an expandable underwater vehicle for inspecting an underwater inspection object, comprising a first underwater vehicle having a vehicle position estimation means, a second underwater vehicle having an imaging means for imaging the inspection object, an optical transmission means provided on the second underwater vehicle for transmitting image information captured by the imaging means to the first underwater vehicle by underwater optical communication, an optical receiving means provided on the first underwater vehicle for receiving the image information, and an underwater repeater having a repeater propulsion means and a repeater position measurement means. The system is characterized in that it is equipped with a surface repeater capable of moving near a surface, an information transmission line connecting the first underwater vehicle and the surface repeater and transmitting the image information received by the first underwater vehicle, and a control means for controlling the second underwater vehicle, the first underwater vehicle, and the surface repeater, and the control means causes the first underwater vehicle to track the second underwater vehicle while maintaining it within a predetermined distance range and a predetermined relative orientation range from the second underwater vehicle, and controls the second underwater vehicle to capture images of the inspection object by transmitting instructions to the surface repeater, the information transmission line, and the first underwater vehicle.

Here, the object to be inspected is a marine structure including an offshore wind power generation facility having a linear structure around it, and it is preferable to control the tracking position of the first underwater vehicle to be kept within the specified distance range and the specified relative orientation range so that the information transmission line does not intersect with the linear structure.

It is also preferable to provide a mother ship having a position setting means for setting a target latitude and a target longitude for the surface repeater and the first underwater vehicle, and for the mother ship and the surface repeater to transmit information including the target latitude, the target longitude, and the image information using wireless communication.

It is also preferable that the first underwater vehicle has a gripping means for gripping the second underwater vehicle, and the control means controls the position of the surface repeater based on the target latitude and the target longitude set by the position setting means and the surface position measured by the repeater position measuring means, and controls the position of the first underwater vehicle based on the underwater position estimated by the vehicle position estimating means, so as to control the first underwater vehicle and the surface repeater to run side by side while maintaining their vertical positional relationship up to the target latitude and the target longitude.

It is also preferable that the control means controls the imaging means provided on the first underwater vehicle to capture an image of the second underwater vehicle when the first underwater vehicle is gripped by the gripping means.

It is also preferable that, when the first underwater vehicle grasps the second underwater vehicle, the control means controls underwater optical communication of the image captured by the imaging means of the second underwater vehicle using the optical transmitting means provided on the second underwater vehicle and the optical receiving means provided on the first underwater vehicle.

In addition, when the first underwater vehicle and the surface relay aircraft reach the vicinity of the inspection object located at the set target latitude and target longitude, it is preferable that the control means releases the gripping means of the first underwater vehicle to release the second underwater vehicle, and controls the second underwater vehicle to approach the inspection object for inspection.

It is also preferable that the first underwater vehicle has a position detection means including an imaging means for detecting the position of the second underwater vehicle, and the control means controls to correct the positions of the first underwater vehicle and the water relay so as to track the detected position of the second underwater vehicle.

It is also preferable that the first underwater vehicle has a first illumination means for illuminating the second underwater vehicle on the same side as the light receiving means.

It is also preferable that the wavelength of the underwater optical communication is different from the wavelength of the first lighting means of the first underwater vehicle.

It is also preferable to provide an optical filter including a short wavelength cut filter in the imaging means of the first underwater vehicle, and to attenuate the light of the wavelength of the underwater optical communication by the optical filter, thereby reducing the effect of the light of the underwater optical communication on the imaging by the imaging means of the first underwater vehicle.

It is also preferable that the second underwater vehicle has a second illumination means for illuminating the inspection object on the opposite side to the optical transmission means.

It is also preferable that the control means is capable of controlling the navigation of the second underwater vehicle, the first underwater vehicle, and the water relay vehicle in any one of a WP (Way Point) navigation mode, a SLAM (Simultaneous Localization and Mapping) navigation mode, and a remotely operated navigation mode.

It is also preferable that in the remote control navigation mode, at least the second underwater vehicle can be remotely controlled by an operator.

It is also preferable that the repeater position measurement means has a Global Navigation Satellite System (GNSS) receiver and an Attitude Heading Reference System (AHRS).

It is also preferable that the vessel position estimation means has an inertial navigation system (INS) and a Doppler ground speed indicator (DVL), or an attitude heading reference system (AHRS) and a Doppler ground speed indicator (DVL).

It is also preferable that the water repeater has a surface camera and an underwater camera, the surface camera captures the surrounding water area on the water, and the underwater camera captures the information transmission line, and the control means controls the transmission of water area capture information of the surrounding water area and the transmission line capture information.

In addition, the method of operating the underwater vehicle-surface repeater connection system includes a vehicle introduction step of introducing the first underwater vehicle carrying the second underwater vehicle into water, a repeater introduction step of introducing the surface repeater to the water surface, a vertical position securing step of bringing the surface repeater and the first underwater vehicle into a vertical positional relationship, an initial position input step of transmitting the surface position of the surface repeater to the first underwater vehicle via an information transmission line and inputting it as the initial underwater position of the first underwater vehicle, and a step of inputting the surface position of the object to be inspected to the surface repeater. The method includes a target position setting step for setting a target latitude and a target longitude, a target position input step for transmitting and inputting the set target latitude and the target longitude to the first underwater vehicle via the information transmission line, a navigation control step for controlling the surface relay aircraft and the first underwater vehicle to travel in parallel toward the target latitude and the target longitude while maintaining the vertical positional relationship, and a vehicle release step for releasing the second underwater vehicle held by the first underwater vehicle after the first underwater vehicle has reached the vicinity of the target latitude and the target longitude.

Here, it is preferable to have an inspection step in which, after the vehicle opening step, an operator operates the position of the second underwater vehicle while viewing image information captured by the second underwater vehicle, and inspects the inspection object.

It is also preferable to have a tracking step in which the first underwater vehicle tracks the second underwater vehicle as the second underwater vehicle moves in accordance with the operation of the operator in the inspection step, while transmitting the image information transmitted from the second underwater vehicle by underwater optical communication via the information transmission line.

It is also preferable to have a repeater tracking step of moving the surface repeater to follow the first underwater vehicle when there is no room for the information transmission line due to the movement of the first underwater vehicle.

In addition, if the distance between the mother ship and the surface repeater is long and wireless communication is not possible, it is preferable to have a repeater movement step for moving the surface repeater to a position where communication with the mother ship is possible.

It is also preferable to have a vehicle holding step in which, during retrieval, the second underwater vehicle is moved to the vicinity of the first underwater vehicle by an operator and the first underwater vehicle is made to hold the second underwater vehicle, and a retrieval step in which the surface repeater and the first underwater vehicle are moved to the vicinity of the mother ship, the surface repeater is retrieved to the mother ship, and the first underwater vehicle and the held second underwater vehicle are housed in the mother ship by handling the information transmission line.

According to the expandable surface repeater and underwater vehicle connection system corresponding to claim 1, there is provided an underwater vehicle-surface repeater connection system having an expandable underwater vehicle for inspecting an underwater inspection object, comprising a first underwater vehicle having a vehicle position estimation means, a second underwater vehicle having an imaging means for imaging the inspection object, an optical transmitting means provided on the second underwater vehicle for transmitting image information captured by the imaging means to the first underwater vehicle by underwater optical communication, an optical receiving means provided on the first underwater vehicle for receiving the image information, a surface repeater having a repeater propulsion means and a repeater position measurement means and capable of moving near the water surface, and a system for connecting the first underwater vehicle and the surface repeater. The system includes an information transmission line that transmits the image information received by the first underwater vehicle, and a control means that controls the second underwater vehicle, the first underwater vehicle, and the surface repeater, and the control means causes the first underwater vehicle to track the second underwater vehicle while maintaining the first underwater vehicle within a predetermined distance range and a predetermined relative direction range, and controls the second underwater vehicle to capture an image of the inspection object by transmitting instructions to the second underwater vehicle via the surface repeater, the information transmission line, and the first underwater vehicle. This allows the second underwater vehicle to inspect or work on the inspection object without causing any trouble such as getting caught on the inspection object because the second underwater vehicle does not have an information transmission line. In addition, large amounts of image information such as captured images acquired by the second underwater vehicle can be transmitted to a mother ship or the like at high speed and stably via the surface repeater.

The object to be inspected is a marine structure including an offshore wind power generation facility having a linear structure around it, and by controlling the tracking position of the first underwater vehicle while keeping it within the specified distance range and the specified relative orientation range so that the information transmission line does not cross the linear structure, inspection and work on the object to be inspected can be performed without the second underwater vehicle getting caught on the linear structure, and further without the information transmission line connecting the first underwater vehicle and the surface repeater getting caught on the linear structure.

In addition, a mother ship having a position setting means for setting a target latitude and a target longitude for the surface repeater and the first underwater vehicle is provided, and the mother ship and the surface repeater transmit information including the target latitude, the target longitude and the image information using wireless communication, so that the surface repeater and the first underwater vehicle can be appropriately moved to a target location while maintaining an appropriate relative positional relationship between them according to instructions from the mother ship.

The first underwater vehicle has a gripping means for gripping the second underwater vehicle, and the control means controls the position of the surface repeater based on the target latitude and longitude set by the position setting means and the surface position measured by the repeater position measuring means, and controls the position of the first underwater vehicle based on the underwater position estimated by the vehicle position estimating means, and controls the first underwater vehicle and the surface repeater to run side by side while maintaining a vertical positional relationship up to the target latitude and target longitude, thereby reliably transporting the second underwater vehicle to the vicinity of the location of the target inspection object.

In addition, when the first underwater vehicle grasps the second underwater vehicle with the gripping means, the control means controls the imaging means provided on the first underwater vehicle to capture an image of the second underwater vehicle, thereby enabling the second underwater vehicle to be reliably grasped by the gripping means of the first underwater vehicle based on the image captured by the first underwater vehicle.

In addition, when the first underwater vehicle grasps the second underwater vehicle, the control means controls the optical transmitting means provided on the second underwater vehicle and the optical receiving means provided on the first underwater vehicle to transmit underwater optical communication of the image of the second underwater vehicle captured by the imaging means, thereby enabling the first underwater vehicle and the second underwater vehicle to communicate underwater optically to confirm each other's status, while the second underwater vehicle can be securely grasped by the grasping means of the first underwater vehicle.

In addition, when the first underwater vehicle and the surface relay aircraft reach the vicinity of the inspection object located at the set target latitude and target longitude, the control means releases the gripping means of the first underwater vehicle, releases the second underwater vehicle, and controls the second underwater vehicle to approach the inspection object for inspection, thereby enabling the first underwater vehicle to reliably transport the second underwater vehicle to the vicinity of the inspection object, and then releasing the second underwater vehicle allows inspection and work to be performed on the inspection object without getting caught on it.

In addition, the first underwater vehicle has a position detection means including an imaging means for detecting the position of the second underwater vehicle, and the control means controls to correct the positions of the first underwater vehicle and the surface repeater so as to track the detected position of the second underwater vehicle, thereby enabling the first underwater vehicle and the surface repeater to reliably track the second underwater vehicle without applying excessive tension to the information transmission line when inspecting or working on the inspection target.

In addition, since the first underwater vehicle has a first illumination means for illuminating the second underwater vehicle on the same side as the optical receiving means, the first illumination means can be used to illuminate the second underwater vehicle while imaging it, and the optical receiving means can reliably receive optical communication signals from the second underwater vehicle.

In addition, by making the wavelength of the underwater optical communication different from the wavelength of the first lighting means of the first underwater vehicle, the influence of the light from the first lighting means can be suppressed, and underwater optical communication between the first underwater vehicle and the second underwater vehicle can be reliably established.

In addition, an optical filter including a short wavelength cut filter is provided in the imaging means of the first underwater vehicle, and the optical filter attenuates the light of the wavelength of the underwater optical communication, thereby reducing the effect of the light of the underwater optical communication on the imaging by the imaging means of the first underwater vehicle, thereby enabling the imaging means to capture images more clearly.

In addition, since the second underwater vehicle has a second illumination means for illuminating the inspection object on the opposite side to the optical transmission means, the inspection object can be imaged while being illuminated by the second illumination means, and underwater optical communication with the first underwater vehicle can be reliably established by the optical transmission means.

In addition, since the control means is capable of controlling the navigation of the second underwater vehicle, the first underwater vehicle, and the surface repeater in any one of a WP (Way Point) navigation mode, a SLAM (Simultaneous Localization and Mapping) navigation mode, and a remotely operated navigation mode, it is possible to reliably control the navigation of the second underwater vehicle, the first underwater vehicle, and the surface repeater in any one of these modes.

In addition, in the remote control navigation mode, at least the second underwater vehicle can be remotely controlled by an operator, thereby ensuring navigation of the second underwater vehicle.

In addition, the repeater position measurement means includes a Global Navigation Satellite System (GNSS) receiver and an Attitude Heading Reference System (AHRS), which allows the position of the water repeater to be accurately determined, and the navigation of the water repeater can be controlled with greater precision.

In addition, by having an inertial navigation system (INS) and a Doppler ground speed indicator (DVL), or an attitude heading reference system (AHRS) and a Doppler ground speed indicator (DVL), the vehicle position estimation means can accurately grasp the positions of the first and second underwater vehicles, and can control the navigation of the first and second underwater vehicles with greater precision.

The water repeater has a surface camera and an underwater camera, and the surface camera captures the surrounding water area on the water and the underwater camera captures the information transmission line. The control means controls the transmission of water area capture information of the surrounding water area and the transmission line capture information, thereby controlling the navigation of the water repeater based on the image captured by the water repeater.

In addition, the method of operating the underwater vehicle-surface repeater connection system includes a vehicle introduction step of introducing the first underwater vehicle carrying the second underwater vehicle into water, a repeater introduction step of introducing the surface repeater to the water surface, a vertical position securing step of bringing the surface repeater and the first underwater vehicle into a vertical positional relationship, an initial position input step of transmitting the surface position of the surface repeater to the first underwater vehicle via an information transmission line and inputting it as the initial underwater position of the first underwater vehicle, a target position setting step of setting the target latitude and target longitude of the inspection object in the surface repeater, and The target position input step transmits and inputs the target latitude and the target longitude to the first underwater vehicle via the information transmission line, the navigation control step controls the surface repeater and the first underwater vehicle to travel in parallel toward the target latitude and the target longitude while maintaining the vertical positional relationship, and the vehicle release step releases the second underwater vehicle held by the first underwater vehicle after reaching the vicinity of the target latitude and the target longitude. This allows the second underwater vehicle to inspect and work on the inspection object without causing any trouble such as getting caught on the inspection object because the second underwater vehicle does not have an information transmission line. In addition, large amounts of image information such as captured images acquired by the second underwater vehicle can be transmitted to a mother ship or the like at high speed and stably via the surface repeater.

Here, after the vehicle opening step, there is an inspection step in which an operator operates the position of the second underwater vehicle while viewing image information captured by the second underwater vehicle, and inspects the object to be inspected. This allows the operator to control the movement of the second underwater vehicle and inspect the object to be inspected while checking the condition of the object to be inspected.

In addition, by having a tracking step in which the first underwater vehicle tracks the second underwater vehicle as the second underwater vehicle moves in accordance with the operation of the operator in the inspection step and transmits the image information transmitted from the second underwater vehicle by underwater optical communication via the information transmission line, the transmission and reception of the image information between the first underwater vehicle and the second underwater vehicle can be more reliably performed.

In addition, by having a repeater tracking step of moving the surface repeater to follow the first underwater vehicle when there is no room in the information transmission line due to the movement of the first underwater vehicle, the relative positions of the first underwater vehicle and the surface repeater can be maintained without applying excessive tension to the information transmission line, and inspection or work on the inspection object can be performed by the second underwater vehicle.

In addition, when the distance between the mother ship and the surface repeater is long and wireless communication is not possible, the method includes a repeater movement step for moving the surface repeater to a position where communication with the mother ship is possible, thereby making it possible to more reliably establish wireless communication between the mother ship and the surface repeater.

In addition, by having a vehicle holding step in which the second underwater vehicle is moved to the vicinity of the first underwater vehicle by the operation of an operator during retrieval and the first underwater vehicle is held by the second underwater vehicle, and a retrieval step in which the surface repeater and the first underwater vehicle are moved to the vicinity of the mother ship, the surface repeater is retrieved to the mother ship, and the first underwater vehicle and the held second underwater vehicle are accommodated in the mother ship by handling the information transmission line, the second underwater vehicle can be held by the first underwater vehicle, and then the surface repeater, the first underwater vehicle, and the second underwater vehicle can be recovered to the mother ship.

1 is a conceptual diagram of a configuration of a connection system between an underwater repeater and an underwater vehicle in an embodiment of the present invention. FIG. FIG. 2 is a diagram showing a configuration of a first underwater vehicle in an embodiment of the present invention. FIG. 2 is a diagram showing a configuration of a second underwater vehicle in an embodiment of the present invention. FIG. 2 is a diagram showing the configuration of a water-based repeater in an embodiment of the present invention. FIG. 2 is a diagram showing a configuration of a mother ship according to an embodiment of the present invention. 4 is a flowchart showing the processing performed when an underwater vehicle and a water-based repeater are launched and traveled in an embodiment of the present invention. 5 is a flowchart showing the process of recovering the underwater vehicle and the waterborne relay machine in the embodiment of the present invention.

<Connection system between surface relay aircraft and underwater vehicle>
As shown in Fig. 1, the connection system between the surface repeater and the underwater vehicle in the embodiment of the present invention includes a first underwater vehicle 100 (100-1, 100-2), a second underwater vehicle 102, a surface repeater 200 (200-1, 200-2), and a mother ship 300. The first underwater vehicle 100 and the second underwater vehicle 102 are used underwater between the water surface and the water bottom. The surface repeater 200 is used on the water surface.

Note that FIG. 1 shows a configuration in which a set of the surface repeater 200-1, the first underwater vehicle 100-1, and the second underwater vehicle 102, and a set of the surface repeater 200-2 and the first underwater vehicle 100-1 are operated simultaneously.

The first underwater vehicle 100 and the surface repeater 200 are connected by a cable 400. Note that the connection of the connection system does not simply mean connecting the first underwater vehicle 100 and the surface repeater 200 with a cable 400 or the like, but also includes the first underwater vehicle 100 and the surface repeater 200 sailing in conjunction with each other, working together, etc. Furthermore, in addition to the function of transmitting information, the cable 400 can also be given functions such as transmitting power and towing.

The first underwater vehicle 100 and the second underwater vehicle 102 are connected underwater so that information can be transmitted by optical communication. That is, underwater optical communication is performed between the first underwater vehicle 100 and the second underwater vehicle 102.

The first underwater vehicle 100 and the second underwater vehicle 102 are used to inspect, investigate, repair, etc. the inspection object 500 by autonomously navigating underwater or by operation of an operator from the mother ship 300. The inspection object 500 is not particularly limited, but may be a marine structure including an offshore wind power generation facility having a linear structure around it. However, it is not limited to this, and the inspection object 500 may also be a bottom resource, a bottom cable, etc.

The range of use of the first underwater vehicle 100 is not limited to underwater, and it may be used in rivers, lakes, ponds, marshes, artificial pools, etc. The surface repeater 200 follows the first underwater vehicle 100 and travels on the water, and is used to relay communications between the first underwater vehicle 100 and the mother ship 300. The mother ship 300 receives information about the survey from the first underwater vehicle 100, and provides information for navigation to the first underwater vehicle 100, the second underwater vehicle 102, and the surface repeater 200.

In this embodiment, the mother ship 300 is used, but it is not limited to a ship, and may be a base station located on land, an underwater mother ship located underwater, or an aircraft flying in the air. In particular, in the case of an underwater mother ship located underwater, for example, the underwater mother ship can be placed near the water surface and communicate with the surface repeater 200 using radio waves from an antenna facing the air, or it can be placed completely underwater and communicate directly with the surface repeater 200 using optical communication.

<Configuration of first underwater vehicle>
2, the first underwater vehicle 100 includes a hull 10, a control means 12, a memory means 14, a communication means 16, an optical communication means 17, a navigation means 18, a vehicle position estimation means 20, a vehicle imaging means 22, and a gripping means 23. The first underwater vehicle 100 is, for example, an autonomous underwater vehicle (AUV), but is not limited to this.

The hull 10 is a sealable structure that defines a space such as a cabin. The hull 10 is made of metal, reinforced plastic, etc., and also serves to mechanically support the components of the first underwater vehicle 100. It is preferable that the hull 10 is configured so that the first underwater vehicle 100 has neutral buoyancy.

The control means 12 is a means for controlling various functions in the first underwater vehicle 100. The control means 12 can be a CPU in a computer, etc. The control means 12 comprehensively controls each means mounted on the first underwater vehicle 100 by executing a predetermined control program.

The storage means 14 is a means for storing information used in the first underwater vehicle 100 and the control program of the first underwater vehicle 100. The storage means 14 may be, for example, a semiconductor memory, a hard disk, etc.

The storage means 14 stores information indicating a target position of the first underwater vehicle 100 in controlling the position of the first underwater vehicle 100. The target position is stored, for example, as an initial position and a waypoint (submerged point) including a target latitude and a target longitude. That is, a waypoint (submerged point) indicating the initial position and the route of travel when the hull 10 of the first underwater vehicle 100 travels underwater is set and stored. The initial position and waypoint are information that sequentially represents the underwater route that is the target for travel of the hull 10, using discrete coordinate points. The initial position and waypoint may also be expressed as a combination of the depth from the water surface in addition to the target latitude and target longitude.

The storage means 14 also stores an estimate of the self-position of the first underwater vehicle 100 estimated by the vehicle position estimation means 20 described below. The storage means 14 also stores image information acquired by the vehicle imaging means 22 described below.

The communication means 16 is a means for communicating information between the first underwater vehicle 100 and the surface repeater 200. The communication means 16 receives information from the surface repeater 200 via the information transmission line 24, and transmits information acquired by the first underwater vehicle 100 to the surface repeater 200 via the information transmission line 24. The communication means 16 also functions as a relay means when communicating information between the second underwater vehicle 102 and the surface repeater 200.

The information transmission line 24 can be part of the cable 400. The communication means 16 may employ, for example, Ethernet as a communication protocol. In this case, the information transmission line 24 is an Ethernet cable.

Here, by using wired communication between the first underwater vehicle 100 and the surface repeater 200, it is possible to carry out high-speed, large-capacity communication compared to the method of transmitting acoustic signals underwater. This allows the first underwater vehicle 100 to communicate with the surface repeater 200 and the mother ship 300 at high speed and transmit large volumes of image information, etc.

The length of the information transmission line 24 is preferably set to a sufficient length to allow for a margin relative to the maximum depth of the water area in which the first underwater vehicle 100 and the surface repeater 200 are scheduled to travel. For example, if the maximum depth in which the first underwater vehicle 100 is scheduled to travel is 15 m, the cable length of the information transmission line 24 may be set to 20 m. This allows the first underwater vehicle 100 and the surface repeater 200 to travel side by side while maintaining an appropriate positional relationship. However, the surface repeater 200 may be equipped with a device for reeling out and winding up the information transmission line 24, and the information transmission line 24 may be reeled out or wound up depending on the distance between the first underwater vehicle 100 and the surface repeater 200.

The optical communication means 17 is a means for communicating information between the first underwater vehicle 100 and the second underwater vehicle 102. The optical communication means 17 is configured to include at least an optical receiving means. The optical communication means 17 is not particularly limited, and for example, communication using a visible light laser can be applied. Specifically, the techniques described in Patent Documents 2 and 3 can be applied.

The propulsion means 18 is a means for generating a driving force for propelling the hull 10 and for turning (turning) the hull 10 in the up, down, left and right directions. For example, separate propulsion means 18 are provided on the front, rear, left and right, top and bottom of the hull 10, and separate propulsion means 18 are provided on the left and right, and the hull 10 is turned (turned) in the left and right directions by adjusting the balance of the thrust of the left and right propulsion means 18 without relying on a vertical rudder. In addition, it is configured to include a main propulsion drive motor, a propeller, a rotating shaft, etc. as a mechanism for generating driving force. The main propulsion drive motor is a motor for providing driving force to the hull 10. The main propulsion drive motor rotates the rotating shaft of the propulsion means 18 with a rotation speed and torque according to a drive control signal from the control means 12 by power from a battery. As a result, the propeller connected to the drive shaft is rotated to provide a propulsive force to the hull 10. In addition, the propulsion means 18 includes, for example, a rudder for turning (turning) the hull 10 in the up, down, left and right directions. By tilting the vertical rudder to the right or left relative to the hull 10, the hull 10 can be turned to the left or right. The vertical rudder can be rotated by a vertical rudder drive motor. The vertical rudder drive motor rotates and drives the vertical rudder so that the angle corresponds to the vertical rudder control signal from the control means 12. By tilting the horizontal rudder up or down relative to the hull 10, the hull 10 can be pitched down or up. The horizontal rudder can be driven by a horizontal rudder drive motor. The horizontal rudder drive motor may be configured to rotate and drive the horizontal rudder so that the angle corresponds to the horizontal rudder control signal from the control means 12.

The vehicle position estimation means 20 includes components for estimating the current position of the vessel 10 in the water (underwater position) as its own position. The vehicle position estimation means 20 can be realized, for example, by a programmable microcomputer. The own position of the first underwater vehicle 100 estimated by the vehicle position estimation means 20 is input to the control means 12. The control means 12 stores the inputted own position of the first underwater vehicle 100 in the memory means 14 and uses it to control the position of the first underwater vehicle 100.

The vehicle position estimation means 20 may be configured to include an inertial navigation system (INS). The inertial navigation system includes a speedometer that measures the speed of the first underwater vehicle 100. The speedometer may be configured, for example, by a Doppler ground speed meter (DVL). In inertial navigation, the self-position of the first underwater vehicle 100 is estimated by integrating the speed of the first underwater vehicle 100 detected by the speedometer to determine the distance traveled by the first underwater vehicle 100 from the starting point.

The vehicle position estimation means 20 may also be configured to include an attitude and heading reference system (AHRS). The attitude and heading reference system is a type of inertial navigation system that uses a gyroscope or the like, and is combined with a speedometer such as a Doppler ground speed indicator (DVL) to calculate and output the rotational and linear motion of the first underwater vehicle 100 in the water. The vehicle position estimation means 20 estimates the self-position of the first underwater vehicle 100 by integrating the rotational and linear motion of the first underwater vehicle 100 calculated by the attitude and heading reference system to determine the distance traveled by the first underwater vehicle 100 from the starting point.

The vehicle position estimation means 20 may also include a depth gauge for measuring the underwater depth of the first underwater vehicle 100. The depth of the first underwater vehicle 100 measured by the depth gauge is input to the control means 12. The control means 12 stores the input depth of the first underwater vehicle 100 in the memory means 14 and uses it to control the depth of the first underwater vehicle 100.

The sailing control of the hull 10 is performed based on the self-position estimated by the vessel position estimation means 20. The control means 12 sequentially reads out waypoints preset in the storage means 14, and controls the sailing means 18 so as to reduce the difference between the waypoints and the self-position of the hull 10 estimated by the vessel position estimation means 20.

The control of the propulsion means 18 may be based on a hull motion model. The hull motion model is also called AUV dynamics and is made up of equations of motion that represent the motion performance of the hull 10 in water. Specifically, control may be based on the response characteristics of the propulsion means 18 and the movement characteristics of the hull 10.

The navigation means 18 is controlled according to underwater vehicle correction information that corrects the self-position of the hull 10 estimated by the vehicle position estimation means 20. The control means 12 controls the navigation means 18 to move the hull 10 closer to the target position by correcting the target position for navigation according to the underwater vehicle correction information transmitted from the mother ship 300. In other words, the navigation means 18 is controlled according to the underwater vehicle correction information, and position errors based on the initial position of the hull 10 and the waypoint settings, as well as position errors in the estimation of the self-position by the vehicle position estimation means 20, can be compensated for.

The navigation of the first underwater vehicle 100 is not limited to the waypoint (WP) navigation mode using waypoints as described above. For example, a SLAM (Simultaneous Localization and Mapping) navigation mode that combines self-position estimation and the creation of an environmental map of the area around the first underwater vehicle 100 may be applied. A remote-operated navigation mode based on operations by an operator on board the mother ship 300 may also be applied.

The lighting means 19 is a means for illuminating the outside of the vessel 10 underwater in the first underwater vehicle 100. The lighting means 19 can be used as illumination when imaging by the vehicle imaging means 22. For example, when imaging and tracking the second underwater vehicle 102, the second underwater vehicle 102 can be clearly imaged by irradiating it with light by the lighting means 19. It is preferable that the wavelength of the light irradiated by the lighting means 19 is different from the wavelength of the light used in underwater optical communication by the optical communication means 17. This makes it possible to suppress mutual interference between the illumination by the lighting means 19 and the underwater optical communication by the optical communication means 17.

It is preferable that the lighting means 19 is disposed on the same side of the hull 10 of the first underwater vehicle 100 as the optical communication means 17. In other words, when the first underwater vehicle 100 tracks the second underwater vehicle 102 while taking an image of the second underwater vehicle 102, the lighting means 19 illuminates the second underwater vehicle 102 while taking an image, and tracking is performed based on the image while optical communication with the second underwater vehicle 102 can be reliably established.

The watercraft imaging means 22 is configured to include components for imaging the outside of the vessel hull 10. The watercraft imaging means 22 can be, for example, a camera for capturing still images, a video for capturing video, etc. Image information (imaging data) relating to the images and videos obtained by the watercraft imaging means 22 is stored in the storage means 14. In addition, the image information (imaging data) relating to the images and videos obtained by the watercraft imaging means 22 is transmitted to the waterborne repeater 200 via the information transmission line 24 using the communication means 16.

In addition, multiple vehicle imaging means 22 may be provided to acquire the relative position between the vessel 10 and the target based on stereoscopic vision. This relative position information can be used to correct errors in estimating the self-position of the first underwater vehicle 100 by the vehicle position estimation means 20 described below.

In addition, in this embodiment, the first underwater vehicle 100 is provided with a vehicle imaging means 22, but any means capable of acquiring the underwater situation in the first underwater vehicle 100 may be used. For example, sonar using sound waves or ultrasonic waves may be used to acquire the shape of structures and the bottom of the water. In this case, the acquired information is stored in the memory means 14 and is transmitted to the water repeater 200 via the information transmission line 24 using the communication means 16.

The vehicle imaging means 22 may further be provided with an optical filter 22a. The optical filter 22a is preferably a filter that attenuates the wavelength of light used for optical communication by the optical communication means 17. Generally, the wavelength of light used by the optical communication means 17 is shorter than the wavelength of light irradiated by the illumination means 19, so the optical filter 22a is preferably a short-wavelength cut filter that attenuates the shorter wavelength side of the wavelength of light used by the optical communication means 17. By providing the optical filter 22a, the effect of the light of underwater optical communication on the imaging by the vehicle imaging means 22 can be reduced.

The gripping means 23 is a means for holding the second underwater vehicle 102 by the first underwater vehicle 100. The first underwater vehicle 100, while holding the second underwater vehicle 102 by the gripping means 23, navigates to the vicinity of the target position where the second underwater vehicle 102 will perform inspection or work, and then releases the gripping means 23 to release the second underwater vehicle 102. Furthermore, when the inspection or work is completed, the first underwater vehicle 100 retrieves the second underwater vehicle 102 and navigates while still being held by the gripping means 23.

<Configuration of the second underwater vehicle>
As shown in the schematic diagram of Fig. 3, the second underwater vehicle 102 includes a boat hull 10, a control means 12, a memory means 14, an optical communication means 17, a navigation means 18, a vehicle position estimation means 20, and a vehicle imaging means 22. The second underwater vehicle 102 is, for example, an autonomous unmanned underwater vehicle (AUV), but is not limited to this. The configuration of the second underwater vehicle 102 is similar to that of the first underwater vehicle 100, except that the second underwater vehicle 102 does not include the communication means 16 and the gripping means 23.

The hull 10 is a sealable structure that defines a space such as a cabin. The hull 10 is made of metal, reinforced plastic, etc., and also serves to mechanically support the components of the second underwater vehicle 102. It is preferable that the hull 10 is configured so that the second underwater vehicle 102 has neutral buoyancy.

The control means 12 is a means for controlling various functions in the second underwater vehicle 102. The control means 12 can be a CPU in a computer, etc. The control means 12 comprehensively controls each means mounted on the second underwater vehicle 102 by executing a predetermined control program.

The storage means 14 is a means for storing information used in the second underwater vehicle 102 and the control program of the second underwater vehicle 102. The storage means 14 may be, for example, a semiconductor memory, a hard disk, etc.

The memory means 14 stores information indicating a target position of the second underwater vehicle 102 in controlling the position of the second underwater vehicle 102. The target position is stored, for example, as an initial position and a waypoint (submerged point) including a target latitude and a target longitude. That is, a waypoint (submerged point) indicating the initial position and the route of travel when the hull 10 of the second underwater vehicle 102 travels underwater is set and stored. The initial position and waypoint are information that sequentially represents the underwater route that is the target for travel of the hull 10, using discrete coordinate points. The initial position and waypoint may also be expressed as a combination of the depth from the water surface in addition to the target latitude and target longitude.

The storage means 14 also stores an estimate of the self-position of the second underwater vehicle 102 estimated by the vehicle position estimation means 20 described below. The storage means 14 also stores image information acquired by the vehicle imaging means 22 described below.

The optical communication means 17 is a means for communicating information between the first underwater vehicle 100 and the second underwater vehicle 102. The optical communication means 17 is configured to include at least an optical transmission means. The optical communication means 17 is not particularly limited, and for example, communication using a visible light laser can be applied. Specifically, the techniques described in Patent Documents 2 and 3 can be applied.

The propulsion means 18 is a means for generating a driving force for propelling the hull 10 and for turning (swivel) the hull 10 in the vertical and horizontal directions. The propulsion means 18 is similar to the propulsion means 18 in the first underwater vehicle 100, so a description thereof will be omitted.

The vehicle position estimation means 20 includes components for estimating the current position of the vessel 10 in the water (underwater position) as its own position. The vehicle position estimation means 20 can be realized, for example, by a programmable microcomputer. The own position of the second underwater vehicle 102 estimated by the vehicle position estimation means 20 is input to the control means 12. The control means 12 stores the inputted own position of the second underwater vehicle 102 in the memory means 14 and uses it to control the position of the second underwater vehicle 102.

The vehicle position estimation means 20 may be configured to include an inertial navigation system (INS). The inertial navigation system includes a speedometer that measures the speed of the second underwater vehicle 102. The speedometer may be configured, for example, by a Doppler ground speed meter (DVL). In inertial navigation, the self-position of the second underwater vehicle 102 is estimated by integrating the speed of the second underwater vehicle 102 detected by the speedometer to determine the distance traveled from the starting point of the second underwater vehicle 102.

The vehicle position estimation means 20 may also be configured to include an attitude and heading reference system (AHRS). The attitude and heading reference system is a type of inertial navigation system that uses a gyroscope or the like, and is combined with a speedometer such as a Doppler ground speed indicator (DVL) to calculate and output the rotational and linear motion of the second underwater vehicle 102 in the water. The vehicle position estimation means 20 estimates the self-position of the second underwater vehicle 102 by integrating the rotational and linear motion of the second underwater vehicle 102 calculated by the attitude and heading reference system to determine the distance traveled from the starting point of the second underwater vehicle 102.

The vehicle position estimation means 20 may also include a depth gauge for measuring the underwater depth of the second underwater vehicle 102. The depth of the second underwater vehicle 102 measured by the depth gauge is input to the control means 12. The control means 12 stores the input depth of the second underwater vehicle 102 in the memory means 14 and uses it to control the depth of the second underwater vehicle 102.

The sailing control of the hull 10 is performed based on the self-position estimated by the vessel position estimation means 20. The control means 12 sequentially reads out waypoints preset in the storage means 14, and controls the sailing means 18 so as to reduce the difference between the waypoints and the self-position of the hull 10 estimated by the vessel position estimation means 20.

The control of the propulsion means 18 may be based on a hull motion model. The hull motion model is also called AUV dynamics and is made up of equations of motion that represent the motion performance of the hull 10 in water. Specifically, control may be based on the response characteristics of the propulsion means 18 and the movement characteristics of the hull 10.

The navigation means 18 is controlled according to underwater vehicle correction information that corrects the self-position of the hull 10 estimated by the vehicle position estimation means 20. The control means 12 controls the navigation means 18 to bring the hull 10 closer to the target position by correcting the target position for navigation according to the underwater vehicle correction information transmitted from the mother ship 300 via the first underwater vehicle 100. In other words, the navigation means 18 is controlled according to the underwater vehicle correction information, and position errors based on the initial position of the hull 10 and the waypoint settings, and position errors in the estimation of the self-position by the vehicle position estimation means 20 can be compensated for.

The navigation of the second underwater vehicle 102 is not limited to the waypoint (WP) navigation mode using waypoints as described above. For example, a SLAM (Simultaneous Localization and Mapping) navigation mode that combines self-position estimation and the creation of an environmental map of the surroundings of the second underwater vehicle 102 may be applied. A remote-operated navigation mode based on operations by an operator on board the mother ship 300 may also be applied.

The lighting means 19 is a means for illuminating the outside of the vessel hull 10 underwater in the second underwater vehicle 102. The lighting means 19 can be used as illumination when imaging by the vehicle imaging means 22. It is preferable that the wavelength of the light emitted from the lighting means 19 is different from the wavelength of the light used for underwater optical communication by the optical communication means 17. This makes it possible to suppress mutual interference between the illumination by the lighting means 19 and the underwater optical communication by the optical communication means 17.

It is preferable to arrange the lighting means 19 on the side of the hull 10 of the second underwater vehicle 102 opposite the optical communication means 17. That is, when the first underwater vehicle 100 tracks the second underwater vehicle 102 while taking images of the second underwater vehicle 102, underwater images can be taken while illuminating the side opposite the underwater optical communication using the lighting means 19, while establishing underwater optical communication with the first underwater vehicle 100 that is being tracked using the optical communication means 17. This makes it possible to further suppress mutual interference between the illumination by the lighting means 19 and the underwater optical communication by the optical communication means 17.

The watercraft imaging means 22 is configured to include components for imaging the outside of the vessel hull 10. The watercraft imaging means 22 can be, for example, a camera for capturing still images, a video for capturing video, etc. Image information (imaging data) relating to the images and videos obtained by the watercraft imaging means 22 is stored in the storage means 14. In addition, image information (imaging data) relating to the images and videos obtained by the watercraft imaging means 22 is transmitted to the first underwater vehicle 100 using the optical communication means 17.

In addition, multiple vehicle imaging means 22 may be provided to acquire the relative position between the vessel 10 and the target based on stereoscopic vision. This relative position information can be used to correct errors in estimating the self-position of the second underwater vehicle 102 by the vehicle position estimation means 20 described below.

The vehicle imaging means 22 may further be provided with an optical filter 22a. The optical filter 22a is preferably a filter that attenuates the wavelength of light used for optical communication by the optical communication means 17. In general, the wavelength of light used by the optical communication means 17 is shorter than the wavelength of light irradiated by the illumination means 19, so the optical filter 22a is preferably a short-wavelength cut filter that attenuates the shorter wavelength side of the wavelength of light used by the optical communication means 17. By providing the optical filter 22a, the influence of the light of the underwater optical communication on the imaging by the vehicle imaging means 22 can be reduced. Note that the optical communication means 17 and the illumination means 19 are arranged on opposite sides in the hull 10 of the second underwater vehicle 102, and if the mutual interference between the optical communication means 17 and the illumination means 19 is small, the optical filter 22a may not be provided.

In addition, in this embodiment, the second underwater vehicle 102 is provided with a vehicle imaging means 22, but any means capable of acquiring underwater conditions in the second underwater vehicle 102 may be used. For example, sonar using sound waves or ultrasonic waves may be used to acquire the shape of structures and the bottom of the water. In this case, the acquired information is stored in the memory means 14 and transmitted to the first underwater vehicle 100 using the optical communication means 17.

<Configuration of water repeater>
4, the water-based repeater 200 according to the embodiment of the present invention is configured to include an aircraft 30, a control means 32, a storage means 34, a communication means 36, a repeater propulsion means 38, a repeater position measurement means 40, and a repeater imaging means 42. The water-based repeater 200 is, for example, an autonomous unmanned sea-based repeater (ASV), but is not limited thereto.

The aircraft body 30 is a sealable structure that forms a space such as a boat room. The aircraft body 30 is made of metal, reinforced plastic, etc., and also plays a role in mechanically supporting the components of the water-based repeater 200.

The control means 32 is a means for controlling various functions in the water repeater 200. The control means 32 can be a CPU in a computer, etc. The control means 32 comprehensively controls each means installed in the water repeater 200 by executing a predetermined control program.

The storage means 34 is a means for storing information used in the water repeater 200 and the control program of the water repeater 200. The storage means 34 can be, for example, a semiconductor memory, a hard disk, etc.

In the storage means 34, information indicating the target position of the water repeater 200 is stored when controlling the position of the water repeater 200. The target position is stored, for example, as an initial position including a target latitude and a target longitude, and a waypoint (sailing point). In other words, waypoints indicating the initial position and sailing route when the water repeater 200's body 30 sails on the water are set and stored. The initial position and waypoint are information that sequentially represents the water route that is the target sailing route of the body 30 with discrete coordinate points.

The storage means 34 also stores information on the self-position of the water repeater 200 measured by the repeater position measurement means 40 described later. The storage means 34 also stores image information acquired by the repeater imaging means 42 described later.

The communication means 36 is a means for communicating information between the surface repeater 200 and the first underwater vehicle 100, and for communicating information between the surface repeater 200 and the mother ship 300. The communication means 36 receives information from the first underwater vehicle 100 via the information transmission line 24, and transmits information to the first underwater vehicle 100 via the information transmission line 24. The communication means 36 also receives information from the mother ship 300 via the wireless communication device 26, and transmits information to the mother ship 300 via the wireless communication device 26. The communication using the wireless communication device 26 may be, for example, a Wi-Fi system using a frequency band of 2.4 GHz. However, this is not limited to this, and may be wireless communication such as UHF communication, VHF communication, optical communication, satellite communication, etc.

In addition, by using wireless communication between the mother ship 300 and the surface repeater 200, the range of movement of the first underwater vehicle 100 and the surface repeater 200 can be expanded compared to the case where wired communication is used.

The communication means 36 is preferably capable of multi-hop communication (mesh Wi-Fi communication) that can relay communication between multiple water repeaters 200. For example, if the distance between the water repeater 200-1 and the mother ship 300 is too far for communication to be established, the communication between the water repeater 200-1 and the mother ship 300 may be relayed by another water repeater 200-2 located between the water repeater 200-1 and the mother ship 300. By moving the water repeater 200-2 in charge of relaying to a position suitable for relaying, communication between the water repeater 200-1 and the mother ship 300 can be more reliably established.

The repeater propulsion means 38 is a means for generating a driving force for propelling the aircraft 30 and for turning (turning) the aircraft 30 in the left-right direction. For example, separate repeater propulsion means 38 are provided on the front, rear, left, right, top and bottom of the aircraft 30, and separate repeater propulsion means 38 are provided on the left and right, and the aircraft 30 is turned (turned) in the left-right direction by adjusting the balance of the thrust of the left and right repeater propulsion means 38 without relying on a vertical rudder. In addition, the main propulsion motor is configured to include a main propulsion motor, a propeller, a rotating shaft, etc. as a mechanism for generating driving force. The main propulsion motor is a motor for providing driving force to the aircraft 30. The main propulsion motor rotates the rotating shaft of the repeater propulsion means 38 with a rotation speed and torque according to a drive control signal from the control means 32 by power from a battery. As a result, the propeller connected to the drive shaft is rotated to provide a propulsive force to the aircraft 30. The repeater propulsion means 38 also includes, for example, a rudder for turning (turning) the aircraft 30 in the left-right direction. By tilting the vertical rudder to the right or left relative to the aircraft 30, the aircraft 30 can be turned to the left or right. The vertical rudder can be rotated by a vertical rudder drive motor. The vertical rudder drive motor rotates and drives the vertical rudder to an angle according to the vertical rudder control signal from the control means 32.

The repeater position measurement means 40 is configured to include components for measuring the current position of the aircraft 30 on the water as its own position. The repeater position measurement means 40 can be realized, for example, by a programmable microcomputer. The own position of the water repeater 200 measured by the repeater position measurement means 40 is input to the control means 32. The control means 32 stores the input own position of the water repeater 200 in the memory means 14 and uses it to control the position of the water repeater 200.

The repeater position measurement means 40 may be configured to include a receiver 40a of a global navigation satellite system (GNSS). The repeater position measurement means 40 measures the current self-position (position on water) of the water repeater 200 based on the GNSS signal received by the receiver 40a. The measured self-position of the water repeater 200 is input to the control means 32 and used to control the position of the water repeater 200. The repeater position measurement means 40 may also be configured to include an attitude and heading reference system (AHRS). The attitude and heading reference system can be used to correct the self-position of the water repeater 200 measured by the repeater position measurement means 40.

The repeater imaging means 42 is configured to include components for imaging the outside of the aircraft 30. The repeater imaging means 42 can be, for example, a camera for capturing still images, a video for capturing videos, etc. The repeater imaging means 42 is preferably equipped with a surface camera for capturing images on the water and an underwater camera for capturing images underwater. The surface camera can capture images of the water area surrounding the surface repeater 200 on the water. The underwater camera can capture images of the water area surrounding the surface repeater 200 underwater. The underwater camera can capture images of, for example, the information transmission line 24 connecting the surface repeater 200 and the first underwater vehicle 100. Image information (imaging data) relating to images and videos obtained by the repeater imaging means 42 is stored in the storage means 34. In addition, image information (imaging data) relating to images and videos obtained by the repeater imaging means 42 is transmitted in real time to the mother ship 300 via the wireless communication device 26 using the communication means 36.

The navigation of the aircraft 30 is controlled based on its own position measured by the repeater position measurement means 40. The control means 32 sequentially reads out waypoints that have been preset in the storage means 34, and controls the repeater propulsion means 38 so as to reduce the difference between the waypoint and the own position of the aircraft 30 measured by the repeater position measurement means 40.

The control of the relay propulsion means 38 may be performed based on a hull motion model. The hull motion model is also called ASV dynamics and consists of a motion equation that represents the motion performance of the aircraft 30 on the water. Specifically, control may be performed based on the response characteristics of the relay propulsion means 38 and the movement characteristics of the aircraft 30.

The navigation of the water repeater 200 is not limited to the waypoint (WP) navigation mode using the above-mentioned waypoints. For example, a SLAM (Simultaneous Localization and Mapping) navigation mode that combines self-position estimation and the creation of an environmental map of the surroundings of the water repeater 200 may be applied. A remote-operated navigation mode based on the operation by an operator on board the mother ship 300 may also be applied.

The surface repeater 200 may run parallel to the first underwater vehicle 100 as it moves. If the surface repeater 200 and the first underwater vehicle 100 are wired via an information transmission line 24, the surface repeater 200 can be linked to the first underwater vehicle 100 by being pulled by the information transmission line 24 as the first underwater vehicle 100 moves.

<Mother ship configuration>
The mother ship 300 in the embodiment of the present invention is a vessel that serves as a base for the first underwater vehicle 100, the second underwater vehicle 102, and the water relay device 200. As shown in the conceptual configuration diagram of Figure 5, the mother ship 300 is configured to include a boat body 50, a positioning means 52, a position setting means 54, an image display means 56, an operation means 58, a connection means 60, and a communication means 62.

The hull 50 is a structure that constitutes the space of the mother ship 300. The hull 50 is made of metal, reinforced plastic, etc., and also plays a role in mechanically supporting the components of the mother ship 300. The hull 50 may also be provided with a navigation means for moving the mother ship 300. If a base station located on land is used instead of the mother ship 300, it is not necessary to provide the hull 50. If an aircraft flying in the air is used instead of the mother ship 300, the hull 50 may be used instead of the aircraft body.

The positioning means 52 includes a device for acquiring the current position of the mother ship 300. The positioning means 52 can be, for example, a positioning means such as a global navigation satellite system (GNSS). However, the positioning means 52 is not limited to this, and may be configured to be able to measure the position of the mother ship 300 according to the distance and direction from a reference point located on land.

The position setting means 54 is a means for setting the positioning information by the positioning means 52 to the first underwater vehicle 100, the second underwater vehicle 102, and the water relay device 200. The position setting means 54 sets the positioning information of the mother ship 300 obtained by the positioning means 52 as initial position information in the vehicle position estimation means 20 of the first underwater vehicle 100 and the second underwater vehicle 102. That is, when the first underwater vehicle 100 and the second underwater vehicle 102 are mounted on the mother ship 300, the positioning information by the positioning means 52 is set in the vehicle position estimation means 20 as the initial position of the first underwater vehicle 100 and the second underwater vehicle 102. The position setting means 54 is also used to set waypoints in the vehicle position estimation means 20 of the first underwater vehicle 100 and the second underwater vehicle 102. The position setting means 54 is also used to set waypoints in the repeater position measurement means 40 of the water repeater 200.

The image display means 56, the operation means 58 and the connection means 60 constitute a monitoring means in the mother ship 300. The monitoring means is used to monitor the position of the first underwater vehicle 100, the position of the second underwater vehicle 102, the position of the surface repeater 200, and the relative positions of the first underwater vehicle 100 and the surface repeater 200, and the relative positions of the first underwater vehicle 100 and the second underwater vehicle 102, and to correct these positions.

The image display means 56 includes a device for displaying images captured by the vehicle imaging means 22 of the first underwater vehicle 100 and the second underwater vehicle 102. That is, the image display means 56 displays underwater images captured by the vehicle imaging means 22 of the first underwater vehicle 100 and the second underwater vehicle 102 based on image information acquired from the first underwater vehicle 100 and the second underwater vehicle 102. By viewing the images displayed on the image display means 56, passengers on the mother ship 300 can confirm the images captured by the first underwater vehicle 100 and the second underwater vehicle 102.

The image display means 56 also includes a device for displaying images captured by the repeater imaging means 42 of the water repeater 200. The image display means 56 can include, for example, a display. That is, the image display means 56 displays underwater and/or surface images captured by the repeater imaging means 42 of the water repeater 200 based on image information acquired from the water repeater 200. Passengers on the mother ship 300 can check the images captured by the water repeater 200 by viewing the images displayed on the image display means 56.

The image display means 56 may be provided separately for each of the first underwater vehicle 100, the second underwater vehicle 102, and the surface repeater 200, or may be configured to be able to switch between the first underwater vehicle 100, the second underwater vehicle 102, and the surface repeater 200 using a selector switch or the like.

The operation means 58 includes a means for performing an operation to correct the positions of the first underwater vehicle 100 and the second underwater vehicle 102. The operation means 58 can be configured to include, for example, a pointing device such as a joystick or a mouse for correcting the positions of the first underwater vehicle 100 and the second underwater vehicle 102. When an administrator on board the mother ship 300 operates the operation means 58, underwater vehicle correction information for moving the first underwater vehicle 100 and the second underwater vehicle 102 in the connection means 60 is generated.

The operating means 58 also includes a means for performing an operation to correct the position of the water repeater 200. The operating means 58 can be configured to include, for example, a pointing device such as a joystick or a mouse for correcting the position of the water repeater 200. When an administrator on board the mother ship 300 operates the operating means 58, water repeater correction information for moving the water repeater 200 in the connecting means 60 is generated.

The operating means 58 also includes a means for adjusting the images captured by the first underwater vehicle 100, the second underwater vehicle 102, and the surface repeater 200. For example, an administrator on board the mother ship 300 can operate the operating means 58 to set imaging conditions such as the distance, angle, angle of view, and lighting from the object to be imaged and inspected for the vehicle imaging means 22 of the first underwater vehicle 100 and the second underwater vehicle 102 and the repeater imaging means 42 of the surface repeater 200.

The operating means 58 may be provided separately for the first underwater vehicle 100, the second underwater vehicle 102, and the surface repeater 200, or may be configured to switch between the first underwater vehicle 100, the second underwater vehicle 102, and the surface repeater 200 using a selector switch or the like.

The linking means 60 is a means for linking the image displayed on the image display means 56 with underwater vehicle correction information for the first underwater vehicle 100 operated by the operation means 58, underwater vehicle correction information for the second underwater vehicle 102, and surface repeater correction information for the surface repeater 200. The linking means 60 can be realized, for example, by a programmable microcomputer. The microcomputer may be common to the control device for controlling the image display means 56 and the operation means 58.

The connecting means 60 generates underwater vehicle correction information for correcting the self-position information estimated by the vehicle position estimation means 20 of the first underwater vehicle 100 according to the amount of operation of the operating means 58. The connecting means 60 generates underwater vehicle correction information such that the amount of correction of the self-position information of the first underwater vehicle 100 increases as the amount of operation of the operating means 58 increases. The connecting means 60 also generates underwater vehicle correction information for correcting the self-position information estimated by the vehicle position estimation means 20 of the second underwater vehicle 102 according to the amount of operation of the operating means 58. The connecting means 60 generates underwater vehicle correction information such that the amount of correction of the self-position information of the second underwater vehicle 102 increases as the amount of operation of the operating means 58 increases. The connecting means 60 also generates underwater repeater correction information for correcting the self-position information measured by the repeater position measurement means 40 of the underwater repeater 200 according to the amount of operation of the operating means 58. The connecting means 60 generates water repeater correction information such that the greater the amount of operation of the operating means 58, the greater the amount of correction to the self-position information of the water repeater 200.

For example, if the operating means 58 is a pointing device such as a joystick or a mouse, underwater vehicle correction information is generated based on the amount and direction of the operation to move the first underwater vehicle 100 in that direction a distance corresponding to the amount of operation. Also, for example, if the operating means 58 is a pointing device such as a joystick or a mouse, underwater vehicle correction information is generated based on the amount and direction of the operation to move the second underwater vehicle 102 in that direction a distance corresponding to the amount of operation. Also, for example, if the operating means 58 is a pointing device such as a joystick or a mouse, underwater repeater correction information is generated based on the amount and direction of the operation to move the underwater repeater 200 in that direction a distance corresponding to the amount of operation. Also, for example, if the operation means 58 is a touch panel integrated with the image display means 56, then underwater vehicle correction information is generated based on the amount and direction of operation by which the target position displayed on the image display means 56 is moved (swiped) on the screen, so as to move the first underwater vehicle 100 in the opposite direction (the direction in which the first underwater vehicle 100 moves in the direction in which the target position is moved in the captured image) a distance corresponding to the amount of operation. The relationship of the amount of correction of the movement distance of the first underwater vehicle 100 to the amount of operation may be set in advance. Also, for example, when the operation means 58 is a touch panel integrated with the image display means 56, underwater vehicle correction information is generated based on the amount and direction of operation by which the target position displayed on the image display means 56 is moved (swiped) within the screen, so that the second underwater vehicle 102 is moved in the opposite direction (the direction in which the second underwater vehicle 102 moves in the direction in which the target position is moved within the captured image) by a distance corresponding to the amount of operation. The relationship of the correction amount of the movement distance of the second underwater vehicle 102 to the amount of operation may be set in advance. Also, for example, when the operation means 58 is a touch panel integrated with the image display means 56, underwater repeater correction information is generated based on the amount and direction of operation by which the target position displayed on the image display means 56 is moved (swiped) within the screen, so that the water repeater 200 is moved in the opposite direction (the direction in which the water repeater 200 moves in the direction in which the target position is moved within the captured image) by a distance corresponding to the amount of operation. The relationship between the amount of operation and the amount of correction for the distance traveled by the water repeater 200 can be set in advance.

This allows the first underwater vehicle 100, the second underwater vehicle 102, and the surface repeater 200 to move to the target position displayed on the screen and face the correct position. Also, the first underwater vehicle 100, the second underwater vehicle 102, and the surface repeater 200 can be moved in real time to the target position displayed on the screen.

The communication means 62 includes a device for receiving information transmitted from the surface repeater 200 to the mother ship 300 and transmitting information from the mother ship 300 to the surface repeater 200. In this embodiment, communication between the first underwater vehicle 100 and the second underwater vehicle 102 and the mother ship 300 is performed via the surface repeater 200, so the mother ship 300 is used as a wireless communication means for communication of the surface repeater 200. When communication of the surface repeater 200 is performed wirelessly, the communication means 62 includes a device for wireless communication using a communication method such as radio waves. Specifically, it may include a wireless communication device such as WiFi communication, UHF communication, satellite communication, etc.

In this embodiment, the underwater vehicle correction information and the surface repeater correction information are generated by the connection means 60 based on the operation of the operation means 58 by the administrator, but the underwater vehicle correction information and the surface repeater correction information may be generated automatically by the connection means 60 (or the operation means 58) without being dependent on the operation of the administrator.

For example, the captured image transmitted from the second underwater vehicle 102 may be image-processed to identify the target position where the target is displayed in the image based on the characteristics (shape, color, etc.) of the target (e.g., a structure to be inspected or repaired), and underwater vehicle correction information may be generated for moving the second underwater vehicle 102 so that the target position is located at the center of the captured image. That is, underwater vehicle correction information may be generated to move the second underwater vehicle 102 in the image by a distance corresponding to the amount of deviation in the direction based on the direction and magnitude of the deviation of the current target position from the center position of the image. Similarly, for example, the captured image transmitted from the first underwater vehicle 100 may be image-processed to identify the target position where the target is displayed in the image based on the characteristics (shape, color, etc.) of the target (e.g., the second underwater vehicle 102 to be followed), and underwater vehicle correction information may be generated for moving the first underwater vehicle 100 so that the target position is located at the center of the captured image. That is, underwater vehicle correction information may be generated so as to move the first underwater vehicle 100 in the direction corresponding to the amount of deviation based on the direction and magnitude of deviation of the current target position from the center position of the image in the image. Also, the captured image transmitted from the water repeater 200 may be image processed to identify the target position where the target is displayed in the image from the characteristics (shape, color, etc.) of the target (e.g., the first underwater vehicle 100 to be followed), and water repeater correction information may be generated to move the water repeater 200 so that the target position is located at the center of the captured image. That is, underwater repeater correction information may be generated so as to move the water repeater 200 in the direction corresponding to the amount of deviation based on the direction and magnitude of deviation of the current target position from the center position of the image in the image.

At this time, the distance between the first underwater vehicle 100, the second underwater vehicle 102, and the surface repeater 200 and the target may be calculated based on the size of the target in the captured image, and the amount of correction to the underwater vehicle correction information and the surface repeater correction information may be adjusted according to the distance.

When the underwater vehicle correction information or the surface repeater correction information is automatically generated in the connection means 60 (or the operation means 58), it is not necessary to have the administrator understand the situation by displaying the captured image on the image display means 56, so the image display means 56 may not display the actual image.

[Processing during launch and operation of underwater vehicles and surface repeaters]
6, the process of deploying and operating the first underwater vehicle 100, the second underwater vehicle 102, and the surface repeater 200 will be described. In this embodiment, the process of deploying the first underwater vehicle 100, the second underwater vehicle 102, and the surface repeater 200 from the mother ship 300 on the water and inspecting an inspection object in the water will be described.

In the following, an example of inspecting an offshore wind power generation facility with linear structures around it will be described, but the object to be inspected is not limited to this. Furthermore, the work to be performed is not limited to inspection, and other work on and underwater may also be performed.

In step S10, the first underwater vehicle 100 and the second underwater vehicle 102 are launched into the water from the mother ship 300. This step corresponds to the launching step. When launching, the second underwater vehicle 102 is held by the gripping means 23 of the first underwater vehicle 100.

In this step, it may be determined whether the measured values of depth (altitude) and speed of the first underwater vehicle 100 and the second underwater vehicle 102 are valid. It is confirmed whether the estimated values of depth (altitude) and speed in the underwater position estimates of the vehicle position estimation means 20 of the first underwater vehicle 100 and the vehicle position estimation means 20 of the second underwater vehicle 102 are valid. If the values are not valid, it is preferable to configure and adjust the vehicle position estimation means 20 of the first underwater vehicle 100 or the second underwater vehicle 102.

In step S12, the water repeater 200 is launched from the mother ship 300. This step corresponds to the repeater launching step. The water repeater 200 is launched onto the water and its horizontal position (latitude and longitude) is maintained at a predetermined position. In this step, underwater imaging may also be performed by the repeater imaging means 42 to check whether imaging processing and transmission and reception processing of the captured images can be performed properly.

In step S14, a process is performed to make the first underwater vehicle 100 and the surface repeater 200 face each other in a vertical position. This step corresponds to a vertical position securing step. First, the first underwater vehicle 100 is lowered into the water. Then, a process is performed to confirm the vertical positional relationship between the first underwater vehicle 100 and the surface repeater 200. In the mother ship 300, it is determined whether the first underwater vehicle 100 and the surface repeater 200 are in a vertical positional relationship with each other from the horizontal position (latitude and longitude) at the self-position transmitted from the first underwater vehicle 100 via the surface repeater 200 and the horizontal position (latitude and longitude) at the self-position transmitted from the surface repeater 200. Here, the vertical positional relationship means that the first underwater vehicle 100 in the water and the surface repeater 200 on the water are in a vertical position with each other. However, the first underwater vehicle 100 and the surface repeater 200 do not need to be in a completely vertical positional relationship, and may be approximately vertical to the extent that they do not impede the navigation or processing of the first underwater vehicle 100 and the surface repeater 200, depending on the margin of the information transmission line 24. If the first underwater vehicle 100 and the surface repeater 200 are not in a vertical positional relationship, the operating means 58 of the mother ship 300 is used to operate the first underwater vehicle 100 and the surface repeater 200 so that they are in a vertical positional relationship with each other.

In step S16, a process is performed to set the position information of the surface repeater 200 as the position information of the initial position of the first underwater vehicle 100. This step corresponds to an initial position input step. With the first underwater vehicle 100 and the surface repeater 200 held in a substantially vertical position, the mother ship 300 acquires the self-position (latitude and longitude) of the surface repeater 200 and transmits the self-position (latitude and longitude) of the surface repeater 200 to the first underwater vehicle 100. The first underwater vehicle 100 sets the self-position (latitude and longitude) of the surface repeater 200 as the initial position (latitude and longitude).

As described above, the process of launching the first underwater vehicle 100, the second underwater vehicle 102, and the surface repeater 200 from the mother ship 300 is realized. Note that in this embodiment, the mode of performing the process of launching the first underwater vehicle 100 and the surface repeater 200 from the mother ship 300 has been described, but the first underwater vehicle 100, the second underwater vehicle 102, and the surface repeater 200 may be launched from land or another floating body instead of the mother ship 300.

In step S18, information on the target position is transmitted from the mother ship 300 to the water repeater 200. This step corresponds to a target position setting step. The position setting means 54 of the mother ship 300 sets the initial position and waypoint information that will be the target position of the water repeater 200 by the operation of the operator, etc., and the target position is set for the water repeater 200 via the communication means 62 of the mother ship 300 and the communication means 36 of the water repeater 200. The target position information is stored in the storage means 34. Specifically, the target position is set for the water repeater 200 by wireless communication using the wireless communication device 26 mounted on the water repeater 200. The target position of the water repeater 200 includes information on the target latitude and target longitude that indicate the initial position and the waypoint.

In step S20, the target position is input to the first underwater vehicle 100. This step corresponds to the target position input step. Target position information is transmitted from the mother ship 300 to the first underwater vehicle 100 via the surface repeater 200. The initial position and waypoint information that will be the target position of the first underwater vehicle 100 is set by the position setting means 54 of the mother ship 300 through the operation of the operator, etc., and the target position is transmitted to the surface repeater 200 via the communication means 62 of the mother ship 300 and the communication means 36 of the surface repeater 200. Furthermore, the target position is input from the surface repeater 200 to the first underwater vehicle 100 via the communication means 36 of the surface repeater 200 and the communication means 16 of the first underwater vehicle 100. Specifically, the target position is input to the first underwater vehicle 100 by wired communication using the information transmission line 24 that connects the surface repeater 200 and the first underwater vehicle 100. The target position information is stored in the storage means 14. The target position of the first underwater vehicle 100 includes information on the target latitude, target longitude, and target depth that indicate the initial position and the waypoint.

In step S22, the navigation of the first underwater vehicle 100 and the water relay device 200 is controlled. This step corresponds to the navigation control step.

The control means 32 of the water repeater 200 sequentially reads out the initial position and waypoints stored in the storage means 34 at a predetermined interval, sets them as the current target position, and performs processing to move the water repeater 200.

First, the position is measured by the water repeater 200. In the water repeater 200, the current position of the aircraft 30 is measured by the repeater position measurement means 40, which includes a global navigation satellite system (GNSS) and the like. Then, a process is performed to determine whether the water repeater 200 is within the reach of the current target position. The control means 32 acquires the current position of the aircraft 30 from the repeater position measurement means 40, and determines whether the current position is within a predetermined reach from the current target position. The reach can be set to a range that is somewhat expanded from the current target position, for example, within a circle of a predetermined radius from the current target position. If the current position is within the predetermined reach from the current target position, a process is performed to maintain the first underwater vehicle 100 and the water repeater 200 at the target position, as described below.

If the current position is not within a predetermined reach from the current target position, the heading of the water repeater 200's sailing direction is measured. In the water repeater 200, the current sailing direction of the aircraft 30 is measured by the repeater position measurement means 40, which includes an attitude heading reference system (AHRS) and the like. Then, a process is performed to sail the water repeater 200 toward the current target position. The control means 32 of the water repeater 200 determines the target traveling direction and target speed to move the water repeater 200 to the current target position based on the measured current position and the measured current heading. Then, the control means 32 sails the water repeater 200 toward the current target position by controlling the repeater propulsion means 38 so that the water repeater 200 moves at the target speed in the target traveling direction.

The control means 12 of the first underwater vehicle 100 sequentially reads out the initial position and waypoints stored in the memory means 14 at a predetermined cycle, sets them as the current target position, and performs processing to move the first underwater vehicle 100.

First, the position is measured in the first underwater vehicle 100. In the first underwater vehicle 100, the vehicle position estimation means 20 estimates the current position of the hull 10 based on the movement from the initial position. Then, a process is performed to determine whether the first underwater vehicle 100 is within the reach of the current target position. The control means 12 obtains an estimate of the current position of the hull 10 from the vehicle position estimation means 20, and determines whether the estimate of the current position is within a predetermined reach from the current target position. The reach can be set to a range that is somewhat expanded from the current target position, for example, within a sphere of a predetermined radius from the current target position. If the current position is within the predetermined reach from the current target position, a process is performed to maintain the first underwater vehicle 100 and the water relay device 200 at the target position, which will be described later.

If the current position is not within a predetermined reach from the current target position, the heading of the sailing direction of the first underwater vehicle 100 is measured. In the first underwater vehicle 100, the heading of the current sailing direction of the hull 10 is measured by the vessel position estimation means 20, which includes an attitude heading reference system (AHRS) and the like. Next, a process is performed to sail the first underwater vehicle 100 toward the current target position. The control means 12 of the first underwater vehicle 100 determines a target traveling direction and a target speed to move the first underwater vehicle 100 to the current target position based on the estimated current position and the measured current heading. Then, the control means 12 sails the first underwater vehicle 100 toward the current target position by controlling the sailing means 18 so that the first underwater vehicle 100 moves at the target speed in the target traveling direction.

The target speed of the first underwater vehicle 100 may be set to match the target speed of the surface repeater 200. This allows the first underwater vehicle 100 and the surface repeater 200 to travel at the same speed, and allows the first underwater vehicle 100 and the surface repeater 200 to maintain an approximately vertical positional relationship even when traveling. However, even if the distance between the first underwater vehicle 100 and the surface repeater 200 increases, the faster one will pull the slower one through the information transmission line 24, and the approximately vertical positional relationship between the first underwater vehicle 100 and the surface repeater 200 will not shift significantly.

The process of maintaining the first underwater vehicle 100 and the surface repeater 200 at the target position is performed as follows. It is determined whether the first underwater vehicle 100 and the surface repeater 200 have both reached the target position and are maintaining the position. It is confirmed that the surface repeater 200 is within the reach of the target position, and after it is confirmed that the first underwater vehicle 100 is within the reach of the target position, it is determined whether the surface repeater 200 and the first underwater vehicle 100 are both maintaining the target position. If the first underwater vehicle 100 and the surface repeater 200 are both maintaining the target position, the navigation process is terminated. If the surface repeater 200 is not maintaining the target position, control is performed so that the surface repeater 200 maintains the target position. If the first underwater vehicle 100 is not maintaining the target position, control is performed so that the first underwater vehicle 100 maintains the target position.

When the first underwater vehicle 100 and the surface repeater 200 reach the target position and are moved by operating the first underwater vehicle 100, the surface repeater 200 is set to a tracking mode for the first underwater vehicle 100, which tracks the horizontal position (latitude and longitude) of the first underwater vehicle 100. For example, when there is no room in the information transmission line, the self-position (latitude and longitude) estimated by the vehicle position estimation means 20 of the first underwater vehicle 100 is transmitted to the surface repeater 200, and the surface repeater 200 is caused to sail so that the self-position measured by the repeater position measurement means 40 approaches the target position with the estimated self-position (latitude and longitude) as the target position.

However, in order to prevent the surface repeater 200 from moving around too sensitively as the first underwater vehicle 100 sails, a tolerance may be set for the distance between the horizontal position (latitude and longitude) of the first underwater vehicle 100 and the horizontal position (latitude and longitude) of the surface repeater 200. For example, if the distance between the horizontal position (latitude and longitude) of the first underwater vehicle 100 and the horizontal position (latitude and longitude) of the surface repeater 200 is within 5 m, the surface repeater 200 may be set not to track the first underwater vehicle 100.

In step S24, a process of releasing the second underwater vehicle 102 is performed. This step corresponds to a vehicle releasing step. In step S22, when the first underwater vehicle 100 and the surface repeater 200 reach the target latitude and target longitude, and the first underwater vehicle 100 reaches the target depth, the second underwater vehicle 102 is released from the first underwater vehicle 100. An instruction to release the gripping means 23 and release the second underwater vehicle 102 is transmitted from the mother ship 300 to the first underwater vehicle 100 via the surface repeater 200 and the information transmission line 24 by an operator's operation or the like. When the first underwater vehicle 100 receives the instruction, it releases the gripping means 23 and releases the second underwater vehicle 102 underwater.

In step S26, the inspection object is inspected. This step corresponds to the inspection step. The second underwater vehicle 102, which was released from the first underwater vehicle 100 in step S22, is brought close to the inspection object, and an image of the inspection object is captured using the vehicle imaging means 22 of the second underwater vehicle 102. At this time, the inspection object can be captured in a brightly lit state using the lighting means 19 of the second underwater vehicle 102. In addition, the operator can use the operation means 58 of the mother ship 300 to set imaging conditions such as the distance, angle, angle of view, and lighting from the inspection object for the second underwater vehicle 102.

The captured image information is transmitted from the second underwater vehicle 102 to the first underwater vehicle 100 using the optical communication means 17 of the second underwater vehicle 102 and the optical communication means 17 of the first underwater vehicle 100. The image information is also transferred from the first underwater vehicle 100 to the surface repeater 200 via the information transmission line 24, and is further transferred from the surface repeater 200 to the mother ship 300 via the wireless communication device 26. In this way, the image captured by the second underwater vehicle 102 is transmitted from the second underwater vehicle 102 to the mother ship 300 in real time.

The operator can also use the operating means 58 of the mother ship 300 to control the sailing of the second underwater vehicle 102. The operator can correct the position of the second underwater vehicle 102 by operating the operating means 58 while checking the image captured by the second underwater vehicle 102 on the image display means 56 of the mother ship 300. That is, the horizontal position (latitude and longitude) and depth (altitude) of the second underwater vehicle 102 are corrected to the desired position by transmitting underwater vehicle correction information from the mother ship 300 to the second underwater vehicle 102.

The navigation control of the second underwater vehicle 102 may be performed by setting waypoints that are the target positions for navigation for the second underwater vehicle 102. That is, the position setting means 54 of the mother ship 300 sets information on waypoints that are the target positions for the second underwater vehicle 102, and the information is set in the second underwater vehicle 102 via the surface repeater 200 and the first underwater vehicle 100. The second underwater vehicle 102 sequentially reads out the set waypoints at a predetermined cycle, sets them as actual target positions, and performs processing to move the second underwater vehicle 102.

Here, the second underwater vehicle 102 is cable-free relative to the first underwater vehicle 100, so even if the object to be inspected has linear structures around it, such as an offshore wind power generation facility that is tethered to the seabed by mooring lines and has power lines attached, inspection and work can be carried out without the information transmission lines 24 etc. becoming tangled or caught.

In step S28, tracking control is performed by the first underwater vehicle 100 and the surface relay device 200. This step corresponds to a tracking step. In step S26, the second underwater vehicle 102 captures an image of the inspection object, and the vehicle imaging means 22 of the first underwater vehicle 100 captures an image of the second underwater vehicle 102. At this time, the second underwater vehicle 102 can be captured in a brightly illuminated state using the lighting means 19 of the first underwater vehicle 100. In addition, the operator can use the operation means 58 of the mother ship 300 to set imaging conditions such as the distance, angle, angle of view, and lighting between the first underwater vehicle 100 and the second underwater vehicle 102.

The captured image information is transmitted from the first underwater vehicle 100 to the surface repeater 200 via the information transmission line 24. It is further transferred from the surface repeater 200 to the mother ship 300 via the wireless communication device 26. In this way, the image captured by the first underwater vehicle 100 is transmitted in real time from the first underwater vehicle 100 to the mother ship 300. The operator can use the operation means 58 of the mother ship 300 to control the first underwater vehicle 100 to track the second underwater vehicle 102. The operator can correct the position of the first underwater vehicle 100 by operating the operation means 58 while checking the image captured by the first underwater vehicle 100 on the image display means 56 of the mother ship 300. That is, by transmitting underwater vehicle correction information from the mother ship 300 to the first underwater vehicle 100, the horizontal position (latitude and longitude) and depth (altitude) are corrected to the desired position so that the first underwater vehicle 100 tracks the second underwater vehicle 102 while remaining within a specified distance range and a specified relative orientation range.

Here, the first underwater vehicle 100 is moved so that the information transmission line 24 connecting the first underwater vehicle 100 and the surface relay device 200 does not interfere with the underwater inspection object. In addition, it is preferable to position the first underwater vehicle 100 so that the second underwater vehicle 102 is not hidden behind the inspection object when viewed from the first underwater vehicle 100.

As described above, the first underwater vehicle 100 can establish high-speed communication with the surface repeater 200 via the information transmission line 24, while tracking the second underwater vehicle 102 while performing optical communication with the second underwater vehicle 102 from a safe location away from the object to be inspected, such as an offshore wind power generation facility.

Furthermore, if necessary, the surface repeater 200 is controlled to track the first underwater vehicle 100. This step corresponds to the repeater tracking step. This control is executed when there is no room in the information transmission line 24 connecting the first underwater vehicle 100 and the surface repeater 200, when the first underwater vehicle 100 and the surface repeater 200 are unable to maintain a substantially vertical position, when it is unclear whether they are maintaining a substantially vertical position, etc.

By transmitting an imaging control signal from the mother ship 300 to the surface repeater 200, the underwater area near the surface repeater 200 is imaged by the repeater imaging means 42 of the surface repeater 200. The captured image is transmitted from the surface repeater 200 to the mother ship 300, and the image is displayed on the image display means 56 of the mother ship 300. Next, it is determined whether the first underwater vehicle 100 can be confirmed. The operator on the mother ship 300 determines whether the first underwater vehicle 100 can be confirmed in the image displayed on the image display means 56. If the first underwater vehicle 100 cannot be confirmed in the image, a rise control signal is transmitted from the mother ship 300 to the first underwater vehicle 100 via the surface repeater 200, and a process of raising the first underwater vehicle 100 is performed. When the first underwater vehicle 100 receives the ascent control signal, it raises the first underwater vehicle 100 until the first underwater vehicle 100 can be seen in the image captured by the surface repeater 200. At this time, the second underwater vehicle 102 may be raised together with the first underwater vehicle 100.

When the first underwater vehicle 100 can be confirmed in the image, it is determined whether the first underwater vehicle 100 and the surface repeater 200 are in an appropriate vertical positional relationship. The operator on the mother ship 300 determines whether the first underwater vehicle 100 and the surface repeater 200 are in an approximately vertical positional relationship in the image displayed on the image display means 56. If the first underwater vehicle 100 and the surface repeater 200 are not in an approximately vertical positional relationship in the image, the surface repeater 200 is moved and a process is performed to correct the first underwater vehicle 100 and the surface repeater 200 to an approximately vertical positional relationship. While checking the image displayed on the image display means 56 on the mother ship 300, the operator operates the operation means 58 to send a movement control signal to the surface repeater 200, and the surface repeater 200 is caused to sail so that the surface repeater 200 is in an approximately vertical positional relationship with the first underwater vehicle 100. Then, a process is performed to lower the first underwater vehicle 100 to the target depth. At this time, the second underwater vehicle 102 may be moved and lowered together with the first underwater vehicle 100.

If necessary, control is performed to maintain communication between the water repeater 200 and the mother ship 300. This step corresponds to a repeater movement step. This control is executed when wireless communication between the water repeater 200 and the mother ship 300 is no longer established.

When the wireless communication conditions between the water-based repeater 200 and the mother ship 300 deteriorate or become impossible, control is performed to move the water-based repeater 200 closer to the mother ship 300 based on the initial position information input in step S16.

Furthermore, communication between the water repeater 200 and the mother ship 300 may be established by multi-hop communication (mesh Wi-Fi communication) via another water repeater 200. For example, if the distance between the water repeater 200-1 and the mother ship 300 is long and wireless communication conditions deteriorate or become impossible, the mother ship 300 controls the movement of another water repeater 200-2 located between the water repeater 200-1 and the mother ship 300, thereby moving the water repeater 200-2 between the water repeater 200-1 and the mother ship 300. This makes it possible to more reliably establish communication between the water repeater 200-1 and the mother ship 300 by relaying through the water repeater 200-2.

In step S30, a determination is made as to whether or not the inspection has been completed. This step corresponds to the inspection completion step. If the inspection has not been completed, the process returns to step S26, and the second underwater vehicle 102 continues inspecting the inspection target. If the inspection is to be completed, the process proceeds to the recovery process described below.

As described above, the process of deploying, sailing, and inspecting the first underwater vehicle 100, the second underwater vehicle 102, and the surface repeater 200 is realized in the connection system between the surface repeater and the underwater vehicle.

[Processing when recovering underwater vehicles and surface repeaters]
7, a process for recovering the first underwater vehicle 100, the second underwater vehicle 102, and the surface repeater 200 will be described. In this embodiment, a process for recovering the first underwater vehicle 100 and the second underwater vehicle 102 in the water and the surface repeater 200 on the water to the mother ship 300 on the water will be described.

In step S40, the first underwater vehicle 100 carries out a process of holding the second underwater vehicle 102. This step corresponds to a vehicle holding step. When the inspection of the inspection object by the second underwater vehicle 102 is completed, the operator moves the second underwater vehicle 102 to the vicinity of the first underwater vehicle 100 by operating the operation means 58 of the mother ship 300. At this time, the first underwater vehicle 100 and the second underwater vehicle 102 are imaged by the vehicle imaging means 22 of the first underwater vehicle 100 and the vehicle imaging means 22 of the second underwater vehicle 102, and the captured images are transmitted to the mother ship 300 via the water relay device 200. In the mother ship 300, the image is displayed on the image display means 56. While checking the image, the operator controls the navigation of the second underwater vehicle 102 so that the second underwater vehicle 102 approaches the first underwater vehicle 100. Then, the second underwater vehicle 102 is held by the first underwater vehicle 100 by gripping it with the gripping means 23 of the first underwater vehicle 100. The holding form can take various forms such as docking or storage other than gripping. In order to have the first underwater vehicle 100 hold the second underwater vehicle 102, it is preferable that the second underwater vehicle 102 is smaller than the first underwater vehicle 100, and it is also preferable that the second underwater vehicle 102 is small when inspecting an inspection object with a complex shape or an inspection object with a linear structure.

In step S42, a process is performed to call up the stored initial positions of the first underwater vehicle 100 and the surface repeater 200. This step corresponds to an initial position call step. The mother ship 300 instructs the surface repeater 200 to return to the initial position by wireless communication between the mother ship 300 and the surface repeater 200. Accordingly, an instruction to return to the initial position is transferred from the surface repeater 200 to the first underwater vehicle 100 via the information transmission line 24. The initial position uses the information input and stored in the first underwater vehicle 100 and the surface repeater 200 in step S16, but may be newly set in the first underwater vehicle 100 and the surface repeater 200 based on the current position of the mother ship 300. If the mother ship 300 has moved from the initial position, the newly set current position is also interpreted as being included in the initial position.

In step S44, control is performed to navigate the first underwater vehicle 100 and the surface repeater 200 to their initial positions. This step corresponds to a navigation control step. This step can be performed in the same manner as step S22 above, by changing the target positions of the first underwater vehicle 100 and the surface repeater 200 to the initial positions set in step S42. Through the navigation control, the first underwater vehicle 100, the second underwater vehicle 102 held by the first underwater vehicle 100, and the surface repeater 200 move to the vicinity of the mother ship 300.

In step S46, the first underwater vehicle 100, the second underwater vehicle 102, and the surface repeater 200 are lifted. This step corresponds to the lifting step. First, the surface repeater 200 is lifted onto the mother ship 300. Furthermore, by pulling the information transmission line 24 connecting the surface repeater 200 and the first underwater vehicle 100, the first underwater vehicle 100 and the second underwater vehicle 102 held by the first underwater vehicle 100 are lifted onto the mother ship 300.

As described above, the first underwater vehicle 100, the second underwater vehicle 102, and the surface relay aircraft 200 on the water can be lifted onto the mother ship 300 on the water.

The present invention can be applied to highly accurate navigation control of underwater vehicles and monitoring of targets. In other words, it can improve work efficiency in the inspection, monitoring, repair, etc. of underwater targets by the underwater vehicle while maintaining the positional relationship between the underwater vehicle and the surface repeater. For example, it can be used for bottom environmental surveys (seaweed, seaweed, coral, etc.), fishery resource surveys (demersal fish, shellfish, etc.), fishery equipment inspections (fish pens, fish reefs, etc.), inspection of the underwater parts of port facilities (quays, breakwaters, etc.), inspection of the underwater parts of offshore wind power generation facilities, underwater pipeline inspection of oil and gas facilities, ship bottom inspection, inspection of the underwater parts of dam lakes, etc.

10 Vessel body, 12 Control means, 14 Memory means, 16 Communication means, 17 Optical communication means, 18 Navigation means, 19 Illumination means, 20 Vessel position estimation means, 22 Vessel imaging means, 22a Optical filter, 23 Gripping means, 24 Information transmission line, 26 Wireless communication device, 30 Aircraft body, 32 Control means, 34 Memory means, 36 Communication means, 38 Repeater propulsion means, 40 Repeater position measurement means, 40a Receiver, 42 Repeater imaging means, 50 Vessel body, 52 Positioning means, 54 Position setting means, 56 Image display means, 58 Operation means, 60 Connection means, 62 Communication means, 100 First underwater vehicle, 102 Second underwater vehicle, 200 Surface repeater, 300 Mother ship, 400 Cable, 500 Inspection object.

Claims (23)

An underwater vehicle-surface repeater connection system having an expandable underwater vehicle for inspecting an underwater inspection object, comprising:
a first underwater vehicle having a vehicle position estimation means;
a second underwater vehicle having an imaging means for imaging the inspection object;
an optical transmission means provided in the second underwater vehicle for transmitting image information captured by the imaging means to the first underwater vehicle by underwater optical communication;
an optical receiving means for receiving the image information provided on the first underwater vehicle;
a water-based repeater having a repeater propulsion means and a repeater position measurement means and capable of moving near the water surface;
an information transmission line connecting the first underwater vehicle and the surface repeater and transmitting the image information received by the first underwater vehicle;
a control means for controlling the second underwater vehicle, the first underwater vehicle, and the water-based repeater;
An expandable underwater vehicle-surface repeater connection system, characterized in that the control means controls the first underwater vehicle to track the second underwater vehicle while maintaining it within a predetermined distance range and a predetermined relative orientation range, and controls the second underwater vehicle to capture images of the inspection object by transmitting instructions to the second underwater vehicle via the surface repeater, the information transmission line, and the first underwater vehicle. 2. The expandable underwater vehicle-surface repeater connection system according to claim 1,
The object to be inspected is a marine structure including an offshore wind power generation facility having a linear structure around it, and the expandable underwater vehicle-surface repeater connection system is characterized in that the tracking position of the first underwater vehicle is controlled to maintain the information transmission line within the specified distance range and the specified relative orientation range so that the information transmission line does not intersect with the linear structure. 2. The expandable underwater vehicle-surface repeater connection system according to claim 1,
a mother ship having a position setting means for setting a target latitude and a target longitude for the waterborne repeater and the first underwater vehicle;
An expandable underwater vehicle-surface repeater connection system, characterized in that the mother ship and the surface repeater use wireless communication to transmit information including the target latitude, the target longitude, and the image information. 4. The expandable underwater vehicle-surface repeater connection system according to claim 3,
the first underwater vehicle has a gripping means for gripping the second underwater vehicle,
The control means controls the position of the surface repeater based on the target latitude and target longitude set by the position setting means and the surface position measured by the repeater position measuring means, and controls the position of the first underwater vehicle based on the underwater position estimated by the vehicle position estimation means, thereby controlling the first underwater vehicle and the surface repeater to run side by side while maintaining their vertical positional relationship up to the target latitude and target longitude.This is an expandable underwater vehicle-surface repeater connection system. 5. The expandable underwater vehicle-surface repeater connection system according to claim 4,
An expandable underwater vehicle-surface relay vehicle connection system, characterized in that the control means controls the imaging means provided on the first underwater vehicle to image the second underwater vehicle when the first underwater vehicle grasps the second underwater vehicle with the gripping means. 6. The expandable underwater vehicle-surface repeater connection system according to claim 5,
An expandable underwater vehicle-surface repeater connection system, characterized in that when the first underwater vehicle grasps the second underwater vehicle, the control means controls underwater optical communication of images captured by the imaging means of the second underwater vehicle using the optical transmitting means provided on the second underwater vehicle and the optical receiving means provided on the first underwater vehicle. 5. The expandable underwater vehicle-surface repeater connection system according to claim 4,
An expandable underwater vehicle-surface repeater connection system, characterized in that when the first underwater vehicle and the surface repeater reach the vicinity of the inspection object located at the set target latitude and target longitude, the control means releases the gripping means of the first underwater vehicle to release the second underwater vehicle, and controls the second underwater vehicle to approach the inspection object and inspect it. 2. The expandable underwater vehicle-surface repeater connection system according to claim 1,
An expandable underwater vehicle-surface repeater connection system, characterized in that the first underwater vehicle has a position detection means including an imaging means for detecting the position of the second underwater vehicle, and the control means controls to correct the positions of the first underwater vehicle and the surface repeater so as to track the detected position of the second underwater vehicle. 9. The expandable underwater vehicle-surface repeater connection system according to claim 8,
An expandable underwater vehicle-surface repeater connection system, characterized in that the first underwater vehicle has a first lighting means for illuminating the second underwater vehicle on the same side as the optical receiving means. 10. The expandable underwater vehicle-surface repeater connection system according to claim 9,
An expandable underwater vehicle-surface repeater connection system, characterized in that the wavelength of the underwater optical communication is different from the wavelength of the first lighting means of the first underwater vehicle. 10. The expandable underwater vehicle-surface repeater connection system according to claim 9,
An expandable underwater vehicle-surface repeater connection system, characterized in that an optical filter including a short wavelength cut filter is provided in the imaging means of the first underwater vehicle, and the optical filter attenuates the light of the wavelength of the underwater optical communication, thereby reducing the influence of the light of the underwater optical communication on the imaging by the imaging means of the first underwater vehicle. 2. The expandable underwater vehicle-surface repeater connection system according to claim 1,
The expandable underwater vehicle-surface repeater connection system according to claim 1, characterized in that the second underwater vehicle has a second lighting means for illuminating the inspection object on the opposite side to the optical transmitting means. 2. The expandable underwater vehicle-surface repeater connection system according to claim 1,
The expandable underwater vehicle-surface repeater connection system is characterized in that the control means is capable of controlling the navigation of the second underwater vehicle, the first underwater vehicle, and the surface repeater in any one of a WP (Way Point) navigation mode, a SLAM (Simultaneous Localization and Mapping) navigation mode, and a remotely operated navigation mode. The expandable underwater vehicle-surface repeater connection system according to claim 13,
An expandable underwater vehicle-surface repeater connection system, characterized in that in the remote control navigation mode, at least the second underwater vehicle can be remotely controlled by an operator. 2. The expandable underwater vehicle-surface repeater connection system according to claim 1,
The repeater position measuring means comprises a Global Navigation Satellite System (GNSS) receiver and an Attitude Heading Reference System (AHRS). 2. The expandable underwater vehicle-surface repeater connection system according to claim 1,
The expandable underwater vehicle-surface repeater connection system is characterized in that the vehicle position estimation means has an inertial navigation system (INS) and a Doppler ground speed meter (DVL), or an attitude heading reference system (AHRS) and a Doppler ground speed meter (DVL). 2. The expandable underwater vehicle-surface repeater connection system according to claim 1,
An expandable underwater vehicle-surface repeater connection system, characterized in that the surface repeater has a surface camera and an underwater camera, the surface camera captures images of the surrounding water area on the water and the underwater camera captures images of the information transmission line, and the control means controls the transmission of water area image information of the surrounding water area and image information of the transmission line. A method for operating the expandable underwater vehicle-water surface repeater connection system according to any one of claims 1 to 17, comprising:
a vehicle inserting step of inserting the first underwater vehicle carrying the second underwater vehicle into water;
a repeater throwing step of throwing the water repeater onto the water surface;
a vertical position securing step of positioning the underwater relay aircraft and the first underwater vehicle in a vertical positional relationship;
an initial position input step of transmitting the water position of the surface repeater to the first underwater vehicle via an information transmission line and inputting the water position as an initial underwater position of the first underwater vehicle;
a target position setting step of setting a target latitude and a target longitude of the inspection object on the water-based repeater;
a target position input step of transmitting and inputting the set target latitude and target longitude to the first underwater vehicle via the information transmission line;
a navigation control step of controlling the underwater relay aircraft and the first underwater vehicle to travel in parallel toward the target latitude and the target longitude while maintaining the vertical positional relationship;
and a vehicle opening step of opening the second underwater vehicle possessed by the first underwater vehicle after the first underwater vehicle reaches the vicinity of the target latitude and the target longitude. A method for operating the expandable underwater vehicle-surface repeater connection system according to claim 18, comprising the steps of:
A method for operating an expandable underwater vehicle-surface repeater connection system, characterized in that after the vehicle opening step, an operator operates the position of the second underwater vehicle while viewing image information captured by the second underwater vehicle, and inspects the inspection object. A method for operating the expandable underwater vehicle-surface repeater connection system according to claim 19, comprising the steps of:
A method for operating an expandable underwater vehicle-surface repeater connection system, characterized in that it includes a tracking step in which the first underwater vehicle tracks the second underwater vehicle as the second underwater vehicle moves in accordance with the operator's operation in the inspection step, and transmits the image information transmitted from the second underwater vehicle by underwater optical communication via the information transmission line. A method for operating the expandable underwater vehicle-surface repeater connection system according to claim 20, comprising:
A method for operating an expandable underwater vehicle-surface repeater connection system, characterized in that it includes a repeater tracking step of moving the surface repeater to follow the first underwater vehicle when the information transmission line becomes full due to the movement of the first underwater vehicle. A method for operating an expandable underwater vehicle-surface repeater connection system according to claim 18, which refers to claim 3, comprising:
A method for operating an expandable underwater vehicle-surface repeater connection system, comprising a repeater movement step of moving the surface repeater to a position where communication with the mother ship is possible when the distance between the mother ship and the surface repeater is too long to allow wireless communication. A method for operating an expandable underwater vehicle-surface repeater connection system according to claim 18, which refers to claim 3, comprising:
a vehicle holding step of moving the second underwater vehicle to the vicinity of the first underwater vehicle by an operation of an operator during recovery and causing the first underwater vehicle to hold the second underwater vehicle;
A method for operating an expandable underwater vehicle-surface repeater connection system, comprising a lifting step of moving the surface repeater and the first underwater vehicle close to the mother ship, lifting the surface repeater onto the mother ship, and handling the information transmission line to accommodate the first underwater vehicle and the second underwater vehicle retained therein onto the mother ship.