Position control system for underwater vehicle

Abstract

The purpose of the present invention is to provide an underwater vehicle for which the underwater position thereof can be controlled without using a tether, a control system for the underwater vehicle, and a control method for the underwater vehicle.　An underwater vehicle control system according to the present invention comprises: a master device 20 having a transceiver 21 for underwater optical communication and a single optical pointer 22 for outputting a single wavelength; and an underwater vehicle 10 that is movable in water and performs the underwater optical communication with the master device 20. The master device 20 sequentially emits light Lp from the optical pointer 22 in such a manner as to surround a range Asig in which the underwater optical communication is possible. The underwater vehicle 10 includes: a detection unit 11 that detects the light Lp from the optical pointer 22; a control direction association table in which directions to move in are associated with positions where the light Lp has been detected; a determination unit that identifies the position of the detection of the light Lp from the point in time of the detection of the light Lp by the detection unit 11; and a control unit that moves the underwater vehicle 10 in accordance with the control direction association table on the basis of the position identified by the determination unit.

Description

Underwater equipment position control system

[0001] The present disclosure relates to an underwater device capable of controlling its position in water, a control system therefor, and a control method therefor.

[0002] In recent years, while aerial drones have been under consideration for social implementation, underwater drones are being developed with the aim of innovating in the underwater field. Aerial drones can be controlled wirelessly using radio waves, and location information can be obtained using satellite positioning systems (such as GNSS), so they are being applied to delivery systems using GPS, for example.

[0003] On the other hand, underwater, the transmission characteristics of various physical media are significantly limited compared to air, and the signals of the satellite positioning system required for control use radio waves, which cannot reach underwater, making it difficult to obtain position information. For this reason, current underwater drones are controlled by an operator on board a ship via a cable called a tether (see, for example, Non-Patent Document 1).

[0004] Masaki Minami, "Current Status and Issues of Underwater Drone Systems," Measurement and Control, Vol. 59, No. 7, 2020, pp. 492-496.

[0005] Controlling via such a tether poses the following tether-related challenges: (Challenge 1) Multiple skilled personnel are required for operation, such as pilots and cable operators, which poses the challenge of securing personnel. (Challenge 2) It is necessary to avoid the risk of the underwater drone itself becoming tangled in the tether cable and becoming unable to navigate, which poses the challenge of risk avoidance control. (Challenge 3) There is a challenge in that navigation in narrow spaces is difficult due to the risk of the tether cable becoming tangled in obstacles, which limits the navigation area. (Challenge 4) There is a challenge in that the navigation range is limited to the length of the tether cable.

[0006] Therefore, in order to solve the above problems, an object of the present invention is to provide a master unit capable of controlling the position of underwater equipment without using a tether, a control system for the master unit, and a control method for the master unit.

[0007] In order to achieve the above-mentioned objective, the control system for underwater equipment of the present invention is configured to emit light from an optical pointer so as to surround an area in which underwater optical communication can be performed from the control side, and to give the underwater equipment the ability to move autonomously so as to stay within the area surrounded by the optical pointer.

[0008] Specifically, the underwater equipment control system of the present invention is an underwater equipment control system comprising: a parent unit having a transceiver for underwater optical communication and a single optical pointer that outputs a single wavelength; and underwater equipment that is movable underwater and performs the underwater optical communication with the parent unit, wherein the parent unit sequentially irradiates the light of the optical pointer so as to surround an area where the underwater optical communication is possible, and the underwater equipment comprises: a detection unit that detects the light of the optical pointer; a control direction correspondence table in which the direction to move relative to the position where the light is detected is set; a determination unit that identifies the position from the timing at which the light is detected by the detection unit; and a control unit that moves the underwater equipment in accordance with the control direction correspondence table based on the position identified by the determination unit.

[0009] Furthermore, the underwater equipment control method of the present invention is a method for controlling the position of underwater equipment that is movable underwater and performs underwater optical communication with a parent unit having a transceiver for underwater optical communication and a single optical pointer that outputs a single wavelength, and in which the parent unit sequentially irradiates the light of the optical pointer so as to surround an area in which underwater optical communication is possible, and in which the underwater equipment has a control direction correspondence table in which the direction in which the underwater equipment should move relative to the position of the light of the optical pointer is set, detects the light of the optical pointer, identifies the position from the timing at which the light is detected, and moves the underwater equipment in accordance with the control direction correspondence table based on the identified position.

[0010] The parent unit of the present invention is a parent unit that performs underwater optical communication with underwater equipment that is movable underwater, and is characterized in that it has a transceiver for the underwater optical communication and a single optical pointer, and the optical pointer sequentially irradiates light of a single wavelength so as to surround the range in which the underwater optical communication is possible.

[0011] This underwater device control system can keep the underwater device within the area surrounded by the optical pointer. Therefore, the present invention can provide an underwater device that can control its position underwater without using a tether, a control system for the same, and a control method for the same.

[0012] Here, the light pointer may be configured to irradiate the light at a predetermined position relative to the range, determined by the time, and provide a switching time during which the light is not irradiated when the position is changed, or may be configured to irradiate the light at a predetermined position relative to the range, determined by the time, and notify information about the position change with the light when the position is changed.

[0013] The above inventions can be combined as much as possible.

[0014] The present invention can provide a master unit capable of controlling the position of an underwater device without using a tether, a control system therefor, and a control method therefor.

[0015] FIG. 1 is a table summarizing the characteristics of each communication medium. FIG. 2 is a diagram illustrating an underwater equipment control system according to the present invention. FIG. 3 is a diagram illustrating an underwater equipment control method according to the present invention. FIG. 4 is a diagram illustrating an optical pointer of the underwater equipment control system according to the present invention. FIG. 5 is a diagram illustrating an optical pointer of the underwater equipment control system according to the present invention. FIG. 6 is a diagram illustrating a range of light emitted by an optical pointer of the underwater equipment control system according to the present invention. FIG. 7 is a diagram illustrating the timing of light emission by an optical pointer of the underwater equipment control system according to the present invention. FIG. 8 is a diagram illustrating a control direction correspondence table provided in an underwater equipment according to the present invention. FIG. 9 is a diagram illustrating a range of light emitted by an optical pointer of the underwater equipment control system according to the present invention. FIG. 10 is a diagram illustrating the timing of light emission by an optical pointer of the underwater equipment control system according to the present invention. FIG. 11 is a diagram illustrating a control direction correspondence table provided in an underwater equipment according to the present invention. FIG. 12 is a diagram illustrating an underwater equipment according to the present invention. FIG. 13 is a diagram illustrating an optical pointer of the underwater equipment control system according to the present invention. FIG. 14 is a diagram illustrating a range of light emitted by an optical pointer of the underwater equipment control system according to the present invention. FIG. 15 is a diagram illustrating the timing of light emission by an optical pointer of the underwater equipment control system according to the present invention. FIG. 16 is a diagram illustrating an underwater equipment according to the present invention.

[0016] The following description of the preferred embodiments of the present invention will be given with reference to the accompanying drawings. The preferred embodiments described below are examples of the present invention, and the present invention is not limited to the preferred embodiments. In this specification and the drawings, components having the same reference numerals are intended to represent the same components.

[0017] (Purpose) To resolve the aforementioned issues with current underwater drones requiring tethers, it is necessary to establish a means of communication between the operator and the underwater drone. Figure 1 summarizes the underwater characteristics and issues of each physical medium: sound, light, and radio waves. Considering applications such as transmitting high-definition video from underwater industrial robots, underwater communication using light is an attractive method. However, because light is highly directional and travels in a straight line even underwater, it is necessary to control the underwater drone within the range where optical communication is possible. However, as shown in Figure 1, GNSS signals and control signals, which use radio waves, are absorbed by water and are therefore unsuitable for controlling underwater drones. For this reason, some method is required to autonomously control underwater drones.

[0018] In this embodiment, the control system uses a wavelength-dependent optical pointer to perform vertical and horizontal position correction to achieve the above-mentioned goal of autonomously controlling the underwater drone's position within the range where optical communication is possible. The main features of this control system are as follows: (1) An optical pointer with a wavelength different from the underwater optical communication wavelength is controlled by mechanical or optical control to control the irradiation direction and irradiation range, and emits light to encompass the range where underwater optical communication is possible. (2) The optical pointer can output light of a single wavelength. (3) When the underwater drone detects the optical pointer, it determines its own direction of movement based on the wavelength of the detected pointer (autonomous control). (4) If the underwater drone can no longer detect the optical pointer, it moves (translation, vertical movement, rotation, etc.) to search for the optical pointer. If the underwater drone detects the optical pointer again, it resumes autonomous control from that point.

[0019] 2 is a diagram illustrating an underwater equipment control system according to this embodiment. The underwater equipment control system comprises: a master unit 20 having a transceiver 21 for underwater optical communication and a single optical pointer 22 that outputs a single wavelength; and an underwater device 10 that is movable underwater and performs the underwater optical communication with the master unit 20. The master unit 20 sequentially irradiates light Lp from the optical pointer 22 so as to surround an area Asig where the underwater optical communication is possible. The underwater device 10 comprises: a detection unit 11 that detects the light Lp from the optical pointer 22; a control direction correspondence table in which directions to move relative to positions where the light Lp is detected are set; a determination unit that identifies the position from the timing at which the light Lp is detected by the detection unit 11; and a control unit that moves the underwater device 10 in accordance with the control direction correspondence table based on the position identified by the determination unit.

[0020] If the underwater device 10 moves left and right or forward and backward relative to the parent device 20, the optical signal transmitting and receiving unit of the underwater device 10 will move out of the range Asig where underwater optical communication is possible, making it impossible to communicate with the parent device 20. To avoid this, the underwater device control system performs autonomous position control of the underwater device using a preset control direction correspondence table (movement direction relative to the wavelength of light) and the position where the light of the optical pointer is detected (see Figure 3).

[0021] In other words, this underwater device control method is a control method for controlling the position of an underwater device 10 that is movable underwater and performs underwater optical communication with a master device 20, using the master device 20. The master device 20 has a transceiver 21 for underwater optical communication and a single optical pointer 22 that outputs a single wavelength. First, the master device 20 sequentially irradiates light Lp from the optical pointer 22 so as to surround a range Asig where underwater optical communication is possible (step S01). At this time, the timing for irradiating light Lp from the optical pointer 22 toward each position within the range Asig is predetermined. Here, the underwater device 10 has a control direction correspondence table in which the direction to move is set relative to the position (time) at which the light Lp from the optical pointer 22 is received. The underwater device 10 then detects light Lp from the optical pointer 22 ("Yes" in step S02), identifies the position from the timing at which the light Lp was detected, and moves the underwater device 10 in accordance with the control direction correspondence table based on the identified position (step S03).

[0022] After step S03, or when the underwater device 10 cannot detect the light Lp of the optical pointer 22 ("No" in step S02), it is confirmed whether the underwater device 10 can receive the optical signal Lsig of underwater optical communication (step S04). If the underwater device 10 can receive the optical signal Lsig of underwater optical communication ("Yes" in step S04), the process from step S02 is repeated.

[0023] On the other hand, if the underwater equipment 10 cannot receive the optical signal Lsig of underwater optical communication ("No" in step S04), the underwater equipment 10 moves a predetermined distance toward the sea surface (surfaces a predetermined amount) (step S05) and again checks whether it can receive the optical signal Lsig of underwater optical communication (step S06).

[0024] If the underwater device 10 can receive the optical signal Lsig of underwater optical communication ("Yes" in step S06), the process from step S02 is repeated. On the other hand, if the underwater device 10 cannot receive the optical signal Lsig of underwater optical communication ("No" in step S06), the underwater device 10 is moved or its posture is changed until the detection unit can detect the light Lp of the optical pointer (step S07). Then, the process from step S02 is repeated.

[0025] If the answer is "Yes" in step S04 or S06, the control flow in Fig. 3 may be terminated at that point. In this case, it is preferable to periodically execute the control flow.

[0026] (Example 1) A specific example will be described with reference to Figures 4 to 7. Figure 4 is a diagram illustrating the arrangement of the optical signal transceiver 21 and the optical pointer 22 in the master unit 20 (e.g., the bottom of a ship). Figure 5 is a diagram illustrating the structure of the optical pointer 22. Figure 5(Ax) is a diagram illustrating the structure and operation of the optical pointer 22 that mechanically controls the emission direction of light Lp. The pointer 22 includes a light source 22a that emits light Lp and a direction control unit 22b that changes the direction. The direction control unit 22b changes the direction of the light source 22a, thereby changing the emission direction of the light Lp. Figure 5(Bx) is a diagram illustrating the structure and operation of the optical pointer 22 that optically controls the emission direction of the light Lp. The pointer 22 includes an optical element 22c that emits light Lp and a direction control unit 22d that changes the direction. The direction control unit 22d changes the direction of the optical element 22c, thereby changing the emission direction of the light Lp. The beam system (emitting end of the light Lp) of the light pointer 22 may be configured to combine a light source and an optical system to limit the irradiation range to a square area or the like.

[0027] The optical pointer 22 outputs light Lp of a specified single wavelength. The optical pointer 22 is placed at a position on the parent unit 20 where it can irradiate light Lp so as to surround the range Asig where underwater optical communication is possible. The parent unit 20 controls the movement of the underwater drone in a direction according to the preset position of the output destination of light Lp (time of output). The underwater drone may detect light Lp using color information from image recognition or light wavelength information.

[0028] FIG. 6 is a diagram illustrating the irradiation ranges (Ap1 to Ap4) of light Lp from the optical pointer 22. The light Lp emitted by the optical pointer 22 has the same wavelength throughout the entire irradiation range (Ap1 to Ap4). In this example, the number of irradiation ranges is four. The optical pointer 22 emits light Lp so that the irradiation ranges (Ap1 to Ap4) surround the underwater optical communication range Asig. The size of the irradiation ranges (Ap1 to Ap4) may be adjusted as desired using a lens or the like. Furthermore, although the irradiation ranges (Ap1 to Ap4) are circular in FIG. 6, they may also be adjusted to a polygonal shape using an optical system.

[0029] 7, the optical pointer 22 switches the illumination range (Ap1 to Ap4) at a predetermined time interval and irradiates the light Lp at a predetermined timing for each illumination range (Ap1 to Ap4). That is, in this embodiment, the output of the optical pointer 22 is turned on / off to discretely irradiate each illumination range (the illumination timing is time-divided for each illumination range).

[0030] FIG. 8 is a diagram illustrating the control direction correspondence table provided in the underwater device 10. Because the optical pointer 22 uses light of the same wavelength, the underwater device 10 determines the illumination range (Ap1 to Ap4) when it detects the light Lp from the optical pointer 22 (knowing its own position). The underwater device 10 then operates the drive unit 30 to move in a direction corresponding to the identified illumination range according to the control direction correspondence table. Specifically, if the identified illumination range is Ap1, the drive unit 30 operates to move the underwater device 10 in a southeasterly direction (diagonally downward to the right in FIG. 6 ). By moving the underwater device 10 in a direction corresponding to the illumination range of the detected light Lp (the direction specified in the control direction correspondence table), the underwater device 10 can remain within the range Asig where underwater optical communication is possible. Note that the master unit and the underwater device 10 must be time-synchronized.

[0031] (Example 2) A specific example will be described with reference to Figures 9 to 11. In the underwater equipment control system of this example, the arrangement of the optical signal transceiver 21 and the optical pointer 22 in the master unit 20 (e.g., the bottom of a ship) is the same as that of the underwater equipment control system of Example 1 (Figure 4). The underwater equipment control system of this example differs from the underwater equipment control system of Example 1 in that the optical pointer 22 constantly outputs light Lp while moving the irradiation range of the light Lp. Figure 9 is a diagram illustrating the irradiation ranges (Ap1 to Ap4) of the light Lp from the optical pointer 22. Here, the switching ranges (Ap12, Ap13, Ap24, Ap34) are located between adjacent irradiation ranges (Ap1 to Ap4) and are the ranges when the light Lp moves from one irradiation range to another. Since the optical pointer 22 constantly outputs light, for example, the light Lp moves from irradiation range Ap1 through switching range Ap12 to irradiation range Ap2. In reality, the light Lp from one optical pointer 22 moves, so the light does not overlap. In Figure 9, the trajectory of the center of the light Lp is indicated by the symbol C. The optical pointer 22 irradiates the light Lp clockwise so as to surround the underwater optical communication range Asig. The trajectory C may be counterclockwise or may be polygonal.

[0032] 10 is an image diagram illustrating the timing of irradiation of the light Lp in this embodiment. To improve the control accuracy of the underwater device 10, the range (time) in which the irradiation range (Ap1 to Ap4) switches is also identified as a switching range (Ap12, Ap13, Ap24, Ap34). For example, the pointer 22 may notify the underwater device 10 that the switching range is in progress by flashing the light Lp within the switching range. In this case, the flashing pattern of the light Lp may be different for each switching range.

[0033] FIG. 11 is a diagram illustrating a control direction correspondence table provided in the underwater device 10. The underwater device 10 detects light Lp using color information from image recognition or wavelength information of the light, and identifies the illumination range based on the timing of detection. The underwater device 10 then operates the drive unit 30 to move in a direction corresponding to the identified illumination range in accordance with the control direction correspondence table. Specifically, if the identified illumination range is Ap12, the drive unit 30 is operated so that the underwater device 10 moves south (downward in FIG. 9 ). By moving the underwater device 10 in a direction corresponding to the illumination range of the detected light Lp (the direction specified in the control direction correspondence table) in this way, the underwater device 10 can remain within the range Asig in which underwater optical communication is possible.

[0034] 12 is a configuration diagram illustrating an underwater device 10 according to Examples 1 and 2. The underwater device 10 is movable underwater and performs underwater optical communication with a parent device 20, and includes: a detection unit 11 that detects light of a single wavelength emitted from a single optical pointer 22 of the parent device 20 so as to surround a range Asig in which underwater optical communication is possible; a control direction correspondence table 12 in which directions to move relative to positions in an irradiation range in which light from the optical pointer 22 is emitted (timing of irradiation); a determination unit 13 that identifies the irradiation range from the timing at which the detection unit 11 detects the light; and a control unit 14 that moves the underwater device 10 in accordance with the control direction correspondence table 12, based on the irradiation range identified by the determination unit 13.

[0035] The wavelength of the light from the optical pointer 22 is different from the wavelength of the communication light for the underwater optical communication, and the underwater device 10 further includes an optical separator 15a that separates the light from the optical pointer 22 from the communication light based on the wavelength. The optical separator 15a outputs the separated light from the optical pointer 22 to the detector 11 and the separated communication light to the optical signal receiver 16.

[0036] The detection unit 11 converts the light from the light pointer 22 into an electrical signal, and the determination unit 13 identifies the illumination range from the time of light detection as described above. The attitude control unit 14 checks the illumination range identified by the determination unit 13 against the control direction correspondence table 12 to determine the direction in which to move. The attitude control unit 14 then controls the drive unit 30 to move the underwater device 10 in that direction.

[0037] The underwater device 10 also includes components for underwater optical communication with the parent device 20 (an optical signal receiving unit 16, an optical signal transmitting unit 17, an optical signal processing unit 18, and a transmission information acquiring unit 19). The transmission information acquiring unit 19 acquires information about the environment of the underwater device 10 (e.g., temperature, water pressure, distance to obstacles, etc.). The optical signal processing unit 18 transmits the information about the environment as an optical signal from the optical signal transmitting unit 17 to the parent device 20. The optical signal processing unit 18 also analyzes the optical signal (instructions from the parent device 20) received by the optical signal receiving unit 16 from the parent device 20 and notifies the attitude control unit 14 to operate the underwater device 10 according to the instructions. The instructions from the parent device 20 include, for example, movement instructions (ascending, descending, horizontal movement, turning, etc.). The attitude control unit 14 controls the drive unit 30 to operate in accordance with the instructions from the parent device 20. The optical signal transmitting unit 17 and the optical signal receiving unit 16 may be integrated into a single unit.

[0038] (Configuration Example 2 of Underwater Device) Because signals from the parent device 20 to control the underwater device 10 can be transmitted at a low bit rate, acoustic signals, which have excellent underwater propagation characteristics, may be used, as described in FIG. 1 . In this configuration example, the configuration of an underwater device 10 that can be controlled by acoustic signals is described. FIG. 13 is a configuration diagram illustrating the underwater device 10 of this configuration example. The underwater device 10 of this configuration example differs from the underwater device 10 of Configuration Example 1 in that the optical separator 15a is not required, the detector 11 directly detects light from the optical pointer 22, and the underwater device 10 of Configuration Example 1 is equipped with an acoustic signal receiver 16a and an optical transmission / acoustic reception signal processor 18a instead of the optical signal receiver 16 and optical signal processor 18. Other operations are the same as those of the underwater device 10 of Configuration Example 1.

[0039] (Example 3) A specific example will be described with reference to Figures 14 to 16. Figure 14 is a diagram illustrating the arrangement of the optical signal transceiver 21 and the optical pointer 22 in the master unit 20 (e.g., the bottom of a ship). Figure 15 is a diagram illustrating the irradiation range (Ap1 to Ap4) of the light Lp emitted by the optical pointer 22. In this example, the wavelength of the light Lp from the optical pointer 22 is the same as the wavelength of the communication light for underwater optical communication. As described in Example 1, the optical pointer 22 irradiates light so that the irradiation range (Ap1 to Ap4) surrounds the range Asig in which underwater optical communication is possible. The size of the irradiation range (Ap1 to Ap4) may be adjusted as desired using a lens or the like. Furthermore, although the irradiation range (Ap1 to Ap4) is circular in Figure 15, it may also be adjusted to a polygonal shape using an optical system.

[0040] In this embodiment, since the wavelength of the light from the optical pointer 22 is the same as the wavelength of the communication light, transmission control is performed so that the light from the optical pointer 22 and the communication light are not sent out at the same time. Fig. 16 is a diagram explaining the timing at which the optical pointer 22 irradiates light Lp to each irradiation range and the timing at which data is sent and received by underwater optical communication. The master unit 20 irradiates light in a time-division multiplexing manner so that the irradiation timing of the light from the optical pointer 22 and the irradiation timing of the communication light for underwater optical communication do not overlap. Specifically, the irradiation range Ap1 is irradiated with light Lp at t ０ From t １ The light is irradiated at time t １ From t ２ The light is irradiated at time t ２ From t ３ The light is irradiated at time t ３ From t ４ Light is irradiated at the time t ４ From t ５ During this time, data is transmitted and received by underwater optical communication between the master unit 20 and the underwater device 10. After that, light is emitted in the same manner, starting from the illumination range Ap1.

[0041] The underwater device 10 has the control direction correspondence table described in Fig. 8. As described above, the underwater device 10 can determine, based on the time, which irradiation range the detected light is intended for, and operates the drive unit 12 to move in the direction corresponding to the identified irradiation range according to the control direction correspondence table. By performing autonomous control in this way, the underwater device 10 can stay within the range Asig where underwater optical communication is possible.

[0042] The underwater device 10 may have a control direction correspondence table as described in the second embodiment, and may also use the switching range to improve control accuracy.

[0043] 17 is a configuration diagram illustrating an underwater device 10 according to Example 3. The underwater device 10 is movable underwater and performs underwater optical communication with a parent device 20, and includes: an information processing unit 18b that detects light of a single wavelength irradiated from an optical pointer 22 of the parent device 20 so as to surround a range Asig in which underwater optical communication is possible; a control direction correspondence table 12 in which directions to move for each irradiation range are set; a determination unit 13 that identifies the irradiation range from the timing at which the detection unit 11 detects the light; and a control unit 14 that moves the underwater device 10 in accordance with the control direction correspondence table 12, based on the irradiation range identified by the determination unit 13.

[0044] The wavelength of the light from the optical pointer 22 is the same as the wavelength of the communication light for the underwater optical communication, and the underwater device 10 further includes an optical separator that separates the light from the optical pointer 22 from the communication light based on the timing of the light from each optical pointer 22 being exclusively emitted. In this configuration example, the information processing unit 18b functions as the optical separator. The information processing unit 18b receives an electrical signal converted from the light received by the optical signal receiving unit 16, and outputs information on the light from the optical pointer 22 to the determination unit 13 and information on the separated communication light to the attitude control unit 14.

[0045] The determination unit 13 identifies the illumination range from the light detection time as described above. The attitude control unit 14 checks the illumination range notified by the determination unit 13 against the control direction correspondence table 12 to determine the direction in which to move. The attitude control unit 14 then controls the drive unit 30 to move the underwater device 10 in the selected direction.

[0046] The underwater device 10 also includes components for underwater optical communication with the parent device 20 (an optical signal receiving unit 16, an optical signal transmitting unit 17, an optical signal processing unit, and a transmission information acquiring unit 19). The transmission information acquiring unit 19 acquires information about the environment surrounding the underwater device 10 (e.g., temperature, water pressure, distance to obstacles, etc.). In this configuration example, the information processing unit 18b functions as the optical signal processing unit. The optical signal processing unit transmits the information about the environment as an optical signal from the optical signal transmitting unit 17 to the parent device 20. The optical signal processing unit also analyzes the optical signal received by the optical signal transmitting unit 17 from the parent device 20 (instructions from the parent device 20) and notifies the attitude control unit 14 to operate the underwater device 10 according to the instructions. The instructions from the parent device 20 include, for example, movement instructions (ascending, descending, horizontal movement, turning, etc.). The attitude control unit 14 controls the drive unit 30 to operate in accordance with the instructions from the parent device 20. The optical signal transmitting section 17 and the optical signal receiving section 16 may be integrated into one unit.

[0047] (Configuration example 4 of underwater device) Because the signal used to control the underwater device 10 from the parent device 20 can have a low bit rate, an acoustic signal with excellent underwater propagation characteristics may be used as described in Fig. 1. This configuration example is the same as the configuration of the underwater device 10 described in Fig. 12. Furthermore, the operation of each component is the same as in configuration example 3, except that one cycle includes a period for sending and receiving data via underwater optical communication.

[0048] In the examples other than Example 2, the number of irradiation ranges is four, but the number of irradiation ranges is not limited to four.

[0049] (Effects) The underwater device control system according to the present invention can autonomously control the underwater device 10 to stay within a desired range (a range where stable underwater optical communication is possible) by operating (such as changing the position of the irradiation target) the optical pointer from the master unit 20. Furthermore, since the underwater device control system according to the present invention uses only one optical pointer, it is possible to more economically control the position of the underwater device.

[0050] 10: Underwater device 11: Detection unit 12: Control direction correspondence table 13: Determination unit 14: Attitude control unit 15: Image processing unit 15a: Light separation unit 16: Optical signal receiving unit 16a: Acoustic signal receiving unit 17: Optical signal transmitting unit 18: Optical signal processing unit 18a: Optical transmission / acoustic reception signal processing unit 19: Transmission information acquisition unit 20: Parent unit 21: Optical signal transceiver 22: Optical pointer 30: Drive unit

Claims

1. A parent unit that performs underwater optical communication with underwater equipment that is movable underwater, the parent unit having a transceiver for the underwater optical communication and a single optical pointer, the optical pointer sequentially irradiating light of a single wavelength so as to surround an area in which the underwater optical communication is possible.

2. The parent unit according to claim 1, characterized in that the light pointer shines the light at a predetermined position relative to the range, which is determined by the time, and a switching time is set during which the light is not irradiated when the position is changed.

3. The parent unit according to claim 1, characterized in that the optical pointer irradiates the light at a predetermined position relative to the range, which is determined by the time, and when the position is changed, notifies information of the position change with the light.

4. An underwater equipment control system comprising: a parent unit having a transceiver for underwater optical communication and a single optical pointer that outputs a single wavelength; and underwater equipment that is movable underwater and performs the underwater optical communication with the parent unit, wherein the parent unit sequentially irradiates the light of the optical pointer so as to surround an area where the underwater optical communication is possible, and the underwater equipment comprises: a detection unit that detects the light of the optical pointer; a control direction correspondence table in which the direction to move relative to the position where the light is detected is set; a determination unit that identifies the position from the timing at which the light is detected by the detection unit; and a control unit that moves the underwater equipment in accordance with the control direction correspondence table based on the position identified by the determination unit.

5. An underwater equipment control method for controlling the position of underwater equipment that is movable underwater and performs underwater optical communication with a parent unit having a transceiver for underwater optical communication and a single optical pointer that outputs a single wavelength, comprising the steps of: in the parent unit, sequentially irradiating the light of the optical pointer so as to surround an area in which the underwater optical communication is possible; and in the underwater equipment having a control direction correspondence table in which the direction in which the underwater equipment should move relative to the position of the light of the optical pointer is set, detecting the light of the optical pointer, identifying the position from the timing at which the light is detected, and moving the underwater equipment in accordance with the control direction correspondence table based on the identified position.

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