Underwater mobile system

Abstract

This invention provides an underwater mobile system that does not require a complex configuration or complex calculations for communication via optical wireless technology. [Solution] An underwater mobile system according to one aspect of the present disclosure comprises a first underwater mobile and a second underwater mobile, wherein the system calculates the direction of the second underwater mobile as seen from the first underwater mobile based on the positions of the first underwater mobile and directs a first optical wireless communication device toward the second underwater mobile, and calculates the direction of the first underwater mobile as seen from the second underwater mobile based on the positions of the second underwater mobile and directs a second optical wireless communication device toward the first underwater mobile.

Description

Technical Field

[0001] The present disclosure relates to an underwater vehicle system.

Background Art

[0002] Methods for an underwater vehicle to perform high-speed communication underwater include a method using a communication cable and a method using optical wireless. Among these, in the method using a communication cable, there is a risk that the communication cable may be caught by an obstacle when the underwater vehicle moves. Also, in the method using optical wireless, it is necessary to detect the arrival direction of the light beam transmitted from the communication partner and control the optical wireless communication device to face the arrival direction of the light beam. Patent Document 1 below discloses an underwater optical wireless communication device that receives light while moving a detection light-receiving unit and detects the arrival direction of the light from the light intensity distribution.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The underwater optical wireless communication device described in Patent Document 1 has a complicated structure because it receives light while moving the detection light-receiving unit, and also requires a complicated calculation of detecting the arrival direction of the light after generating the light intensity distribution.

[0005] Therefore, an object of the present disclosure is to provide an underwater vehicle system that does not require a complicated configuration and a complicated calculation when performing communication via optical wireless.

Means for Solving the Problems

[0006] An underwater mobile system according to one aspect of the present disclosure comprises a first underwater mobile and a second underwater mobile, wherein the first underwater mobile includes a first positioning device for measuring or calculating the position of the first underwater mobile, an angle-adjustable first optical wireless communication device, and a first control device, and the second underwater mobile includes a second positioning device for measuring or calculating the position of the second underwater mobile, an angle-adjustable second optical wireless communication device, and a second control device, wherein the first control device acquires the position of the first underwater mobile from the first positioning device and transmits the position of the second underwater mobile from the second underwater mobile via optical wireless communication between the first optical wireless communication device and the second optical wireless communication device. The first optical wireless communication device is directed towards the second underwater mobile body, and the second control device acquires the position of the second underwater mobile body from the second positioning device and acquires the position of the first underwater mobile body from the first underwater mobile body via optical wireless communication between the first and second optical wireless communication devices, and calculates the direction of the first underwater mobile body from the second underwater mobile body based on the position of the second underwater mobile body and the position of the first underwater mobile body, and directs the second optical wireless communication device towards the first underwater mobile body. [Effects of the Invention]

[0007] The above configuration provides an underwater mobile system that does not require a complex configuration or complex calculations when communicating via optical wireless technology. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is an overall diagram of the underwater mobile system. [Figure 2] Figure 2 is a flowchart of the angle adjustment program for the first optical wireless communication device. [Figure 3] Figure 3 is a flowchart of the angle adjustment program for the second optical wireless communication device. [Figure 4] Figure 4 is an overall diagram of the underwater mobile system according to a modified example. [Modes for carrying out the invention]

[0009] (Overall configuration of the underwater mobile system) The embodiments will be described below. First, the overall configuration of the underwater mobile system 100 will be described. Figure 1 is an overall diagram of the underwater mobile system 100. As shown in Figure 1, the underwater mobile system 100 according to this embodiment comprises a first underwater mobile body 10, a second underwater mobile body 20, and a remote control device 30. These components will be described in order below.

[0010] <First Underwater Mobile Unit> The first underwater mobile body 10 is a mobile body that moves underwater while communicating with the second underwater mobile body 20. As shown in Figure 1, the first underwater mobile body 10 in this embodiment includes a first propulsion device 11, a first positioning device 12, a first camera 13, a first optical wireless communication device 14, a first acoustic communication device 15, and a first control device 16. These devices 11 to 16 and the first angle adjustment mechanism 17, which will be described later, are connected to an energy source such as a battery built into the first underwater mobile body 10, or to a power cable included in the communication cable 40, which will be described later.

[0011] The first propulsion device 11 is a device that generates thrust to move the first underwater mobile body 10. In this embodiment, the first propulsion device 11 can move the first underwater mobile body 10 in any orientation and in any direction. The first propulsion device 11 may have a main thruster, a horizontal thruster, and a vertical thruster. The first propulsion device 11 may also have a swivel-type thruster that can change the direction of thrust generation.

[0012] The first positioning device 12 is a device for measuring or calculating the position of the first underwater moving object 10. In this embodiment, the first positioning device 12 is an inertial navigation device that calculates the position of the first underwater moving object 10 based on the distance traveled from the starting point. However, the first positioning device 12 may also be an acoustic positioning device that measures the position of the first underwater moving object 10 based on sound waves transmitted from the mother ship 101.

[0013] The first camera 13 is a camera that images the area around the first underwater moving body 10. The first camera 13 may be a fixed type with a constant imaging direction, or it may be a movable type that can change the imaging direction arbitrarily.

[0014] The first optical wireless communication device 14 is a device that communicates using optical wireless communication with light rays. The first optical wireless communication device 14 can communicate with the second optical wireless communication device 24 of the second underwater mobile body 20, which will be described later, using optical wireless communication. In this embodiment, the first optical wireless communication device 14 communicates with the second optical wireless communication device 24 using visible light rays such as blue light rays and green light rays. The first optical wireless communication device 14 also transmits light rays to the communication partner (the second optical wireless communication device 24 in this embodiment) and receives light rays from the communication partner. Furthermore, the first optical wireless communication device 14 is attached to the first underwater mobile body 10 via a first angle adjustment mechanism 17. The first angle adjustment mechanism 17 can adjust the direction of transmission and reception of light rays of the first optical wireless communication device 14 by adjusting the angle of the first optical wireless communication device 14.

[0015] The first acoustic communication device 15 is a device that communicates using acoustic radio with sound waves. The first acoustic communication device 15 can communicate acoustically with the second acoustic communication device 25 of the second underwater mobile body 20, which will be described later. Acoustic radio communication has the advantage of a wider communication angle range compared to optical radio communication, and also has the advantage of being able to communicate even if there are some obstacles between the communication partner and the communication partner.

[0016] The first control device 16 is a device that controls various equipment mounted on the first underwater mobile body 10. The first control device 16 has a processor, volatile memory, non-volatile memory, and an I / O interface. Various programs, including the angle adjustment program for the first optical wireless communication device 14, are stored in the non-volatile memory of the first control device 16, and the processor performs calculations using the volatile memory based on each program. The "angle adjustment program for the first optical wireless communication device 14" will be described later.

[0017] The first control device 16 is communicably connected to the first propulsion device 11, the first positioning device 12, the first camera 13, the first optical wireless communication device 14, the first acoustic communication device 15, and the first angle adjustment mechanism 17. The first control device 16 can control the first propulsion device 11 by transmitting a control signal to the first propulsion device 11, can acquire the position of the first underwater vehicle 10 from the first positioning device 12, can acquire the first image data captured by the first camera 13 from the first camera 13, can exchange information with the second underwater vehicle 20 via the first optical wireless communication device 14, can exchange information with the second underwater vehicle 20 via the first acoustic communication device 15, and can adjust the angle of the first optical wireless communication device 14 by transmitting a control signal to the first angle adjustment mechanism 17.

[0018] In addition, a communication cable 40 extending from the remote control facility 30 is attached to the first underwater vehicle 10. The first control device 16 is communicably connected to the remote control facility 30 via this communication cable 40. That is, information can be exchanged between the first control device 16 and the remote control facility 30. Although the communication cable 40 in the present embodiment is an optical fiber cable, the communication cable 40 may be an electric cable. Further, the length of the communication cable 40 can be adjusted by winding it around a reel or unwinding it from the reel.

[0019] <Second Underwater Vehicle> The second underwater vehicle 20 is a vehicle that moves underwater while communicating with the first underwater vehicle 10. As shown in FIG. 1, the second underwater vehicle 20 of the present embodiment includes a second propulsion device 21, a second positioning device 22, a second camera 23, a second optical wireless communication device 24, a second acoustic communication device 25, and a second control device 26. Note that these devices 21 to 26 and the second angle adjustment mechanism 27 described later are connected to an energy source such as a battery built into the second underwater vehicle 20.

[0020] The second propulsion device 21 is a device that generates thrust to move the second underwater vehicle 20. The second propulsion device 21 of this embodiment can move the second underwater vehicle 20 in an arbitrary posture in an arbitrary direction. The second propulsion device 21 may have a main propulsion thruster, a horizontal thruster, and a vertical thruster. Further, the second propulsion device 21 may have a swing-type thruster capable of changing the thrust generation direction.

[0021] The second positioning device 22 is a device that measures or calculates the position of the second underwater vehicle 20. The second positioning device 22 of this embodiment is an inertial navigation device similar to the first positioning device 12, but may be an acoustic positioning device or the like.

[0022] The second camera 23 is a camera that images the periphery of the second underwater vehicle 20. The second camera 23 may be a fixed type with a fixed imaging direction, or a movable type capable of arbitrarily changing the imaging direction.

[0023] The second optical wireless communication device 24 is a device that communicates by optical wireless using light rays. The second optical wireless communication device 24 can perform optical wireless communication with the first optical wireless communication device 14 of the first underwater vehicle 10 described above. Further, the second optical wireless communication device 24 transmits light rays to the communication partner (the first optical wireless communication device 14 in this embodiment) and receives light rays from the communication partner. Furthermore, the second optical wireless communication device 24 is attached to the second underwater vehicle 20 via the second angle adjustment mechanism 27. The second angle adjustment mechanism 27 can adjust the transmission and reception direction of the light rays of the second optical wireless communication device 24 by adjusting the angle of the second optical wireless communication device 24.

[0024] The second acoustic communication device 25 is a device that communicates by acoustic wireless using sound waves. The second acoustic communication device 25 can perform acoustic wireless communication with the first acoustic communication device 15 of the first underwater vehicle 10 described above.

[0025] The second control device 26 is a device that controls various equipment mounted on the second underwater mobile body 20. The second control device 26 has a processor, volatile memory, non-volatile memory, and an I / O interface. Various programs, including the angle adjustment program for the second optical wireless communication device 24, are stored in the non-volatile memory of the second control device 26, and the processor performs calculations using the volatile memory based on each program. The "angle adjustment program for the second optical wireless communication device 24" will be described later.

[0026] The second control device 26 is communicatively connected to the second propulsion device 21, the second positioning device 22, the second camera 23, the second optical wireless communication device 24, the second acoustic communication device 25, and the second angle adjustment mechanism 27. The second control device 26 can control the second propulsion device 21 by transmitting a control signal to the second propulsion device 21, acquire the position of the second underwater mobile body 20 from the second positioning device 22, acquire second image data of the image captured by the second camera 23 from the second camera 23, exchange information with the first underwater mobile body 10 via the second optical wireless communication device 24, exchange information with the first underwater mobile body 10 via the second acoustic communication device 25, and adjust the angle of the second optical wireless communication device 24 by transmitting a control signal to the second angle adjustment mechanism 27.

[0027] <Remote control equipment> The remote control equipment 30 is equipment for remotely controlling the first underwater mobile body 10 and the second underwater mobile body 20. In this embodiment, the remote control equipment 30 is installed on the mother ship 101. However, all or part of the remote control equipment 30 may be installed on land, and part of it may consist of portable devices. Furthermore, the remote control equipment 30 may be operated by one person or by multiple people.

[0028] The remote control equipment 30 transmits a first command signal to the first control device 16 of the first underwater mobile body 10 via the communication cable 40. Upon receiving the first command signal, the first control device 16 controls each of the equipment of the first underwater mobile body 10 based on the first command signal, thereby operating the first underwater mobile body 10. In addition, the first image data acquired by the first control device 16 from the first camera 13 is transmitted to the remote control equipment 30 via the communication cable 40, and the first underwater mobile body 10 is controlled based on the first image data.

[0029] Furthermore, the remote control equipment 30 transmits a second command signal to the second control device 26 via the communication cable 40, the first underwater mobile body 10, and the optical wireless communication between the first optical wireless communication device 14 and the second optical wireless communication device 24. Upon receiving the second command signal, the second control device 26 controls each component of the second underwater mobile body 20 based on the second command signal, thereby operating the second underwater mobile body 20. In addition, the second image data acquired by the second control device 26 from the second camera 23 is transmitted to the remote control equipment 30 via the optical wireless communication between the first optical wireless communication device 14 and the second optical wireless communication device 24, the first underwater mobile body 10, and the communication cable 40, and the second underwater mobile body 20 is controlled based on the second image data.

[0030] (Angle adjustment program for the first optical wireless communication device) Next, the angle adjustment program for the first optical wireless communication device 14, which is executed by the first control device 16, will be described. The angle adjustment program for the optical wireless communication device 14 is a program for directing the first optical wireless communication device 14 toward the second underwater mobile body 20 and maintaining optical wireless communication.

[0031] Figure 2 is a flowchart of the angle adjustment program for the first optical wireless communication device 14. As shown in Figure 2, when the angle adjustment program for the first optical wireless communication device 14 is started, the first control device 16 determines whether or not optical wireless communication (hereinafter simply referred to as "optical wireless communication") is available between the first optical wireless communication device 14 and the second optical wireless communication device 24 (step S1). For example, the first control device 16 determines that optical wireless communication is available if it can acquire information from the second underwater mobile body 20 via optical wireless communication, and determines that optical wireless communication is not available (unavailable) if it cannot acquire information from the second underwater mobile body 20 via optical wireless communication.

[0032] In step S1, if it is determined that optical wireless communication is available (YES in step S1), the first control device 16 obtains the position of the second underwater mobile body 20 from the second underwater mobile body 20 via optical wireless communication (step S2). Specifically, the first control device 16 obtains the position of the second underwater mobile body 20 obtained by the second control device 26 from the second positioning device 22 via optical wireless communication.

[0033] On the other hand, if it is determined in step S1 that optical wireless communication is unavailable (NO in step S1), the first control device 16 obtains the position of the second underwater mobile body 20 from the second underwater mobile body 20 via acoustic wireless communication between the first acoustic communication device 15 and the second acoustic communication device 25 (hereinafter simply referred to as "acoustic wireless communication") (step S3). Specifically, the first control device 16 obtains the position of the second underwater mobile body 20 obtained by the second control device 26 from the second positioning device 22 via acoustic wireless communication.

[0034] For example, if the light rays transmitted and received between the first optical wireless communication device 14 and the second optical wireless communication device 24 are temporarily blocked by an obstacle while the second underwater mobile body 20 is moving, optical wireless communication becomes unavailable. Even in this case, since the sound waves transmitted and received between the first acoustic communication device 15 and the second acoustic communication device 25 are less likely to be blocked by obstacles, acoustic wireless communication is basically available.

[0035] After step S2 or S3, the first control device 16 obtains the position of the first underwater moving body 10 from the first positioning device 12 (step S4).

[0036] Next, the first control device 16 calculates the direction of the second underwater moving body 20 as seen from the first underwater moving body 10, based on the position of the second underwater moving body 20 acquired in step S2 or S3, and the position of the first underwater moving body 10 acquired in step S4 (step S5). In step S5, the direction of the second underwater moving body 20 as seen from the first underwater moving body 10 can be easily calculated by using trigonometric functions.

[0037] Next, the first control device 16 transmits a control signal to the first angle adjustment mechanism 17 based on the calculation result of step S5, directing the first optical wireless communication device 14 towards the second underwater mobile body 20 (step S6). This allows the first underwater mobile body 10 to continue communication with the second underwater mobile body 20 via optical wireless communication. After step S6, the first control device 16 returns to step S1 and repeats each step.

[0038] As described above, in this embodiment, if optical wireless communication is unavailable, the first optical wireless communication device 14 is directed towards the second underwater mobile body 20 based on the position of the second underwater mobile body 20 obtained via acoustic wireless communication. However, there may be cases where optical wireless communication remains unavailable because the optical wireless beam is blocked by an obstacle. Therefore, if the period during which optical wireless communication is unavailable continues for a certain period of time or longer, the first control device 16 may move the first underwater mobile body 10 to the first available position where the first underwater mobile body 10 was located when optical wireless communication was available, and may also adjust the angle of the first optical wireless communication device 14 to the first available angle, which is the angle of the first optical wireless communication device 14 when the first underwater mobile body 10 was located in the first available position.

[0039] (Angle adjustment program for the second optical wireless communication device) Next, the angle adjustment program for the second optical wireless communication device 24, executed by the second control device 26, will be described. The angle adjustment program for the second optical wireless communication device 24 is a program for directing the second optical wireless communication device 24 toward the first underwater mobile body 10 and maintaining optical wireless communication. The angle adjustment program for the second optical wireless communication device 24 follows a similar flow to the angle adjustment program for the first optical wireless communication device 14 described above, so it will be explained briefly.

[0040] Figure 3 is a flowchart of the angle adjustment program for the second optical wireless communication device 24. As shown in Figure 3, when the angle adjustment program for the second optical wireless communication device 24 is started, the second control device 26 determines whether or not optical wireless communication is available (step S11).

[0041] If it is determined in step S11 that optical wireless communication is available (YES in step S11), the second control device 26 obtains the position of the first underwater mobile body 10 from the first underwater mobile body 10 via optical wireless communication (step S12).

[0042] On the other hand, if it is determined in step S11 that optical wireless communication is unavailable (NO in step S11), the second control device 26 obtains the position of the first underwater mobile body 10 from the first underwater mobile body 10 via acoustic wireless communication (step S13). As mentioned above, if optical wireless communication is unavailable, the first underwater mobile body 10 also obtains the position of the second underwater mobile body 20 via acoustic wireless communication (step S3). Here, when the first underwater mobile body 10 obtains the position of the second underwater mobile body 20 via acoustic wireless communication, it is configured to transmit information including the position of the first underwater mobile body 10 to the second underwater mobile body 20. Therefore, in step S13, the position of the first underwater mobile body 10 may be obtained using the information transmitted from the first underwater mobile body 10. Similarly, in step S3 as described above, the first control device 16 may obtain the position of the second underwater mobile body 20 using the information transmitted from the second underwater mobile body 20 when optical wireless communication is unavailable.

[0043] After step S12 or S13, the second control device 26 obtains the position of the second underwater moving body 20 from the second positioning device 22 (step S14).

[0044] Next, the second control device 26 calculates the direction of the first underwater moving body 10 as seen from the second underwater moving body 20, based on the position of the first underwater moving body 10 acquired in step S12 or S13 and the position of the second underwater moving body 20 acquired in step S14 (step S15).

[0045] Next, the second control device 26 directs the second optical wireless communication device 24 towards the first underwater mobile body 10 based on the calculation result of step S15 (step S16). As a result, the second underwater mobile body 20 can continue communication with the first underwater mobile body 10 via optical wireless communication.

[0046] As described above, in this embodiment, if optical wireless communication is unavailable, the second optical wireless communication device 24 is directed towards the first underwater mobile body 10 based on the position of the first underwater mobile body 10 obtained via acoustic wireless communication. However, there may be cases where optical wireless communication remains unavailable because the optical wireless beam is blocked by an obstacle. Therefore, if the period during which optical wireless communication is unavailable continues for a certain period of time or longer, the second control device 26 may move the second underwater mobile body 20 to the second available position where it was located when optical wireless communication was available, and adjust the angle of the second optical wireless communication device 24 to the second available angle, which is the angle of the second optical wireless communication device 24 when the second underwater mobile body 20 was located in the second available position.

[0047] The functions of the elements disclosed herein can be performed using circuits or processing circuits, including general-purpose processors, dedicated processors, integrated circuits, ASICs (Application Specific Integrated Circuits), conventional circuits, and / or combinations thereof, configured or programmed to perform the disclosed functions. A processor is considered a processing circuit or circuit because it includes transistors and other circuits. In this disclosure, a circuit, unit, or means is hardware that performs the enumerated functions, or hardware programmed to perform the enumerated functions. The hardware may be hardware disclosed herein, or other known hardware that is programmed or configured to perform the enumerated functions. If the hardware is a processor, which is considered a type of circuit, then the circuit, means, or unit is a combination of hardware and software, and the software is used to configure the hardware and / or the processor.

[0048] (modified version) In the underwater mobile system 100 according to the embodiment described above, the first optical wireless communication device 14 and the first angle adjustment mechanism 17 are installed in only one location on the first underwater mobile body 10, and the second optical wireless communication device 24 and the second angle adjustment mechanism 27 are installed in only one location on the second underwater mobile body 20. However, as shown in Figure 4, the first optical wireless communication device 14 and the first angle adjustment mechanism 17 may be installed in multiple locations on the first underwater mobile body 10 (in Figure 4, two locations on the top and bottom surfaces of the first underwater mobile body 10). Similarly, the second optical wireless communication device 24 and the second angle adjustment mechanism 27 may be installed in multiple locations on the second underwater mobile body 20 (in Figure 4, two locations on the top and bottom surfaces of the second underwater mobile body 20).

[0049] In other words, the first optical wireless communication device 14 may have multiple first optical wireless communication devices 14a and 14b that are installed in different locations. Each of the multiple first optical wireless communication devices 14a and 14b is capable of transmitting and receiving optical wireless rays, and its angle can also be adjusted by the first angle adjustment mechanism 17. It is desirable that the rays transmitted from each of the first optical wireless communication devices 14a and 14b are synchronized, but they do not have to be synchronized. However, if the rays transmitted from each of the first optical wireless communication devices 14a and 14b are not synchronized, each of the first optical wireless communication devices 14a and 14b must use rays with different wavelengths.

[0050] Similarly, the second optical wireless communication device 24 may have multiple second optical wireless communication devices 24a and 24b installed in different locations. Each of the multiple optical wireless communication devices 24a and 24b is capable of transmitting and receiving optical wireless rays, and its angle can be adjusted by the second angle adjustment mechanism 27. It is desirable that the rays transmitted from each of the second optical wireless communication devices 24a and 24b are synchronized, but they do not have to be synchronized. However, if the rays transmitted from each of the second optical wireless communication devices 24a and 24b are not synchronized, each of the second optical wireless communication devices 24a and 24b must use rays with different wavelengths.

[0051] As shown in Figure 4, the first optical wireless communication device 14 has multiple first optical wireless communication devices 14a and 14b. Therefore, even if a light ray transmitted from one first optical wireless communication device 14a is blocked by an obstacle, the light ray transmitted from the other first optical wireless communication devices 14b can still reach the second optical wireless communication device 24.

[0052] Similarly, the second optical wireless communication device 24 shown in Figure 4 has multiple second optical wireless communication devices 24a and 24b. Therefore, even if a light ray transmitted from one second optical wireless communication device 24a is blocked by an obstacle, the light ray transmitted from the other second optical wireless communication devices 24b can still reach the first optical wireless communication device 14. Thus, according to the underwater mobile system 100 shown in Figure 4, communication via optical wireless is less likely to be interrupted.

[0053] Furthermore, the first optical wireless communication device 14 may be installed in only one location on the first underwater mobile body 10, and the second optical wireless communication device 24 may be installed in multiple locations on the second underwater mobile body 20, or the first optical wireless communication device 14 may be installed in multiple locations on the first underwater mobile body 10, and the second optical wireless communication device 24 may be installed in only one location on the second underwater mobile body 20.

[0054] (summary) The first item disclosed herein comprises a first underwater mobile body and a second underwater mobile body, wherein the first underwater mobile body includes a first positioning device for measuring or calculating the position of the first underwater mobile body, an angle-adjustable first optical wireless communication device, and a first control device, and the second underwater mobile body includes a second positioning device for measuring or calculating the position of the second underwater mobile body, an angle-adjustable second optical wireless communication device, and a second control device, wherein the first control device obtains the position of the first underwater mobile body from the first positioning device and obtains the position of the second underwater mobile body from the second underwater mobile body via optical wireless communication between the first optical wireless communication device and the second optical wireless communication device, and the first underwater This is an underwater mobile system in which the direction of the second underwater mobile as seen from the first underwater mobile is calculated based on the position of the intermediate mobile and the position of the second underwater mobile, and the first optical wireless communication device is directed towards the second underwater mobile; the second control device acquires the position of the second underwater mobile from the second positioning device and acquires the position of the first underwater mobile from the first underwater mobile via optical wireless communication between the first and second optical wireless communication devices, calculates the direction of the first underwater mobile as seen from the second underwater mobile based on the position of the second underwater mobile and the position of the first underwater mobile, and directs the second optical wireless communication device towards the first underwater mobile.

[0055] In this configuration, the direction of the second underwater mobile object as seen from the first underwater mobile object is calculated, and the first optical wireless communication device is directed towards the second underwater mobile object. Conversely, the direction of the first underwater mobile object as seen from the second underwater mobile object is calculated, and the second optical wireless communication device is directed towards the first underwater mobile object. However, calculating the direction of the second underwater mobile object as seen from the first underwater mobile object, and the direction of the first underwater mobile object as seen from the second underwater mobile object, does not require a complex configuration or complex calculations. Therefore, according to the above configuration, a complex configuration and complex calculations are not required when communicating via optical wireless communication.

[0056] A second item disclosed herein is the underwater mobile system according to the first item, wherein the first underwater mobile includes a first acoustic communication device, the second underwater mobile includes a second acoustic communication device, the first control device is capable of obtaining the position of the second underwater mobile from the second underwater mobile via acoustic radio between the first and second acoustic communication devices, and the second control device is capable of obtaining the position of the first underwater mobile from the first underwater mobile via acoustic radio between the first and second acoustic communication devices.

[0057] With this configuration, even if optical wireless communication is temporarily unavailable, the first control device can acquire the position of the second underwater mobile object via acoustic wireless communication, and the second control device can acquire the position of the first underwater mobile object via acoustic wireless communication. Therefore, angle adjustments of the first optical wireless communication device and the second optical wireless communication device can be continued, and consequently, communication via optical wireless communication can be continued.

[0058] A third item disclosed herein is an underwater mobile system according to the first or second item, wherein the first optical wireless communication device has a plurality of angle-adjustable first optical wireless communication devices that are installed at different relative positions.

[0059] With this configuration, communication between the first underwater mobile unit and the second underwater mobile unit via optical wireless is less likely to be interrupted.

[0060] A fourth item disclosed herein is an underwater mobile system according to any one of the first to third items, wherein the second optical wireless communication device has a plurality of angle-adjustable second optical wireless communication devices that are installed at different positions relative to each other.

[0061] With this configuration, communication between the first underwater mobile unit and the second underwater mobile unit via optical wireless is less likely to be interrupted. [Explanation of symbols]

[0062] 10. First underwater mobile unit 11 First propulsion device 12. First positioning device 13. Camera 1 14. First Optical Wireless Communication Device 15. First Acoustic Communication Device 16. First control device 17 First angle adjustment mechanism 17a 1st optical wireless communication device 17b 1st optical wireless communication device 20. Second Underwater Mobile Unit 21 2nd propulsion device 22. Second positioning device 23. Second camera 24. Second Optical Wireless Communication Device 25. Second Acoustic Communication Device 26 Second Control Device 27 Second angle adjustment mechanism 27a Second optical wireless communication device 27b Second optical wireless communication device 30 Remote control equipment 40 Communication Cables 100 Underwater Mobile Systems 101 Mothership

Claims

1. The first underwater mobile unit, A second underwater moving body is provided, The first underwater moving body is A first positioning device for measuring or calculating the position of the first underwater moving object, An angle-adjustable first optical wireless communication device, Includes a first control device, The second underwater moving body is A second positioning device for measuring or calculating the position of the second underwater moving object, An angle-adjustable second optical wireless communication device, A second control device, including, The first control device acquires the position of the first underwater mobile body from the first positioning device and the position of the second underwater mobile body from the second underwater mobile body via optical wireless communication between the first optical wireless communication device and the second optical wireless communication device, calculates the direction of the second underwater mobile body as seen from the first underwater mobile body based on the positions of the first underwater mobile body and directs the first optical wireless communication device toward the second underwater mobile body. An underwater mobile system comprising: the second control device, which acquires the position of the second underwater mobile body from the second positioning device and the position of the first underwater mobile body from the first underwater mobile body via optical wireless communication between the first optical wireless communication device and the second optical wireless communication device; calculates the direction of the first underwater mobile body as seen from the second underwater mobile body based on the position of the second underwater mobile body and the position of the first underwater mobile body, and directs the second optical wireless communication device toward the first underwater mobile body.

2. The first underwater mobile body includes a first acoustic communication device, The second underwater mobile body includes a second acoustic communication device, The first control device is capable of obtaining the position of the second underwater mobile body from the second underwater mobile body via acoustic wireless communication between the first acoustic communication device and the second acoustic communication device. The underwater mobile system according to claim 1, wherein the second control device is capable of obtaining the position of the first underwater mobile from the first underwater mobile via acoustic wireless communication between the first acoustic communication device and the second acoustic communication device.

3. The underwater mobile system according to claim 1, wherein the first optical wireless communication device comprises a plurality of angle-adjustable first optical wireless communication devices whose installation positions are different from each other.

4. The underwater mobile system according to claim 3, wherein the second optical wireless communication device comprises a plurality of angle-adjustable second optical wireless communication devices with different installation positions relative to each other.

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