Recovery method and underwater docking device for autonomous underwater vehicle

Abstract

A recovery method for an autonomous underwater vehicle according to one aspect is a recovery method for recovering the autonomous underwater vehicle to a ship in a recovery system including an operator interface device, an underwater docking device that includes a camera and a propeller and that is connected to the ship by a rope, and the autonomous underwater vehicle, which is configured to be capable of docking to the underwater docking device, the recovery method including: sending an image obtained by imaging the autonomous underwater vehicle using the camera from the underwater docking device to the operator interface device; displaying the image on a display; sending an operation command corresponding to an operation of an operator from the operator interface device to the underwater docking device; operating the propeller on the basis of the operation command to cause the underwater docking device to dock to the autonomous underwater vehicle; and recovering the underwater docking device docked to the autonomous underwater vehicle to the ship by drawing in the rope on the ship.

Description

Recovery Method and Underwater Docking Device for Autonomous Unmanned Submersible

[0001] The present disclosure relates to a recovery method and an underwater docking device for an autonomous unmanned submersible.

[0002] Patent Document 1 discloses a system including a station suspended underwater from a ship on the water surface and an autonomous unmanned submersible (AUV: Autonomous Underwater Vehicle; hereinafter also referred to as AUV) that docks with the station. In the system disclosed in Patent Document 1, after the AUV that has completed the operation approaches the station underwater and docks with the station, the station is lifted with the AUV docked thereto and recovered to the ship.

[0003] International Publication No. 2019 / 045103

[0004] In the system of Patent Document 1, when the AUV approaches the station, the positioning of the AUV with respect to the station may not be stably determined due to the influence of ocean currents or the like. Therefore, it is not easy to dock the AUV and the station in a short time, and it has taken time to recover the AUV.

[0005] An object of the present disclosure is to provide a recovery method and an underwater docking device for an autonomous unmanned submersible that can shorten the time required to recover the AUV to the ship.

[0006] A recovery method for an autonomous underwater vehicle according to one aspect of the present disclosure is a recovery system comprising: an operator interface device including an operating device and a display for receiving operator input; an underwater docking device connected to a ship by a rope, including a camera and a propeller; and an autonomous underwater vehicle configured to be dockable with the underwater docking device, wherein the recovery method is for recovering the autonomous underwater vehicle on the ship, and includes sending an image of the autonomous underwater vehicle underwater captured by the camera from the underwater docking device to the operator interface device, displaying the image on the display, sending an operation command from the operator interface device to the underwater docking device in response to the operator input, operating the propeller based on the operation command to dock the underwater docking device with the autonomous underwater vehicle, and recovering the underwater docking device docked with the autonomous underwater vehicle on the ship by pulling in the rope on the ship.

[0007] An underwater docking device according to one aspect of the present disclosure is an underwater docking device configured to dock with an autonomous underwater vehicle in water, comprising: a body connected by a cable to a ship located on or underwater; a propeller disposed on the body; a communication interface configured to communicate with the ship; a camera mounted on the body; and a processing circuit configured to control the propeller based on operation commands received from the ship via the communication interface.

[0008] According to one aspect of this disclosure, the time required to recover the AUV onto the ship can be reduced.

[0009] This is a schematic diagram of the recovery system according to the first embodiment. This is a block diagram showing the configuration of the recovery system in Figure 1. This is a perspective view of the underwater docking device and AUV included in the recovery system in Figure 1. This is a diagram showing the underwater docking device docked to the AUV. This is a schematic diagram showing an example of a docking mechanism for the underwater docking device to dock with the AUV. This is a flowchart showing the flow of recovering the AUV onto a ship using the recovery system in Figure 1. This is a schematic diagram of the recovery system according to the second embodiment. This is a block diagram showing the configuration of the recovery system in Figure 7. This is a schematic diagram of a system for recovering the AUV onto a submersible. This is a schematic diagram showing a modified docking mechanism.

[0010] The embodiments will be described below with reference to the drawings.

[0011] <First Embodiment> Figure 1 is a schematic diagram of the recovery system 1A according to the first embodiment. The recovery system 1A comprises a ship 2, an underwater docking device 3 connected to the ship 2 by a rope 30, and an AUV 4. The ship 2 includes an operator interface device 20, and the underwater docking device 3 is remotely operated from the ship 2 by operation commands from the operator interface device 20. In the recovery system 1A, the AUV 4 and the underwater docking device 3 are docked together underwater, and then the rope 30 connected to the underwater docking device 3 in the docked state is pulled into the ship 2, thereby enabling the AUV 4 to be recovered into the ship 2.

[0012] The following describes the configurations of the ship 2, the underwater docking device 3, and the AUV 4. Figure 2 is a block diagram showing the configuration of the recovery system 1A in Figure 1. Figure 3 is a perspective view of the underwater docking device 3 and the AUV 4 included in the recovery system 1A in Figure 1. Figure 4 shows the underwater docking device 3 docked with the AUV 4.

[0013] (Ship configuration) Ship 2 is sailing or moored on the water. An operator is on board Ship 2 to operate the underwater docking device 3. Ship 2 is equipped with a control device 21, a communication interface 22, an acoustic positioning device 23, an acoustic communication device 24, an operating device 25, a display 26, and a winding device 27. The control device 21, communication interface 22, acoustic positioning device 23, acoustic communication device 24, operating device 25, display 26, and winding device 27 constitute an operator interface device 20 for operating the underwater docking device 3.

[0014] The control device 21 controls the operation of the elements included in the operator interface device 20. In terms of hardware, the control device 21 includes, for example, a processor such as a CPU, and memory such as volatile memory and non-volatile memory. The control device 21 performs various processes by having the processor execute programs stored in memory.

[0015] The communication interface 22 is an interface for communicating with the communication interface 35 of the underwater docking device 3, which will be described later. Communication between the ship 2 and the underwater docking device 3, that is, communication between the communication interface 22 of the ship 2 and the communication interface 35 of the underwater docking device 3, is conducted by wire. The underwater docking device 3 is connected to the ship 2 by a cable 30 extending from it, and this cable 30 includes a communication line for sending and receiving information between the ship 2 and the underwater docking device 3. The cable 30 also includes a power transmission line for supplying electricity from the ship 2 to the underwater docking device 3.

[0016] The acoustic positioning device 23 constitutes an acoustic positioning system that measures the relative position of the ship 2 with respect to the transponder 32 of the underwater docking device 3. The acoustic positioning system will be described later.

[0017] The acoustic communication device 24 communicates with the acoustic communication device 48, which will be described later and is equipped on the AUV 4, using sound. For example, the acoustic communication device 24 can receive information acquired by various devices on the AUV 4, such as the position of the AUV 4, the heading of the AUV 4, and the remaining charge of the AUV 4's battery 42. The acoustic positioning device 23 and the acoustic communication device 24 may be configured as an integrated unit or as separate units.

[0018] The operating device 25 receives input from the operator. For example, the operating device 25 is a device for operating the underwater docking device 3. Specifically, the operating device 25 receives input regarding the underwater posture, orientation, and direction of movement of the underwater docking device 3. The operating device 25 may include levers, buttons, directional keys, a touch panel, a joystick, or any combination thereof.

[0019] The display 26 is, for example, a liquid crystal display. However, the display 26 may be another type of display, such as an organic EL display.

[0020] The winding device 27 winds up and unwinds the rope 30 to which the underwater docking device 3 is connected. In this embodiment, the control device 21 controls the operation of the winding device 27 in response to the operator's operation of the operating device 25. However, the winding device 27 may be controlled by a control unit separate from the control unit that controls the underwater docking device 3. In other words, the winding device 27 does not have to be included in the operator interface device 20.

[0021] (Configuration of the underwater docking device) Next, the configuration of the underwater docking device 3 will be described. As shown in Figure 3, the underwater docking device 3 includes a body 31 connected to the ship 2 by a rope 30. The body 31 is made up of, for example, multiple metal frames or plates connected together.

[0022] As shown in Figure 3, a transponder 32 is positioned on the body 31. The transponder 32 is used to measure the relative position of the underwater docking device 3 relative to the transponder 32 from the ship 2 or AUV 4. The transponder 32, together with the acoustic positioning device 23 or the acoustic positioning device 47 described later, constitutes an acoustic positioning system.

[0023] The acoustic positioning system in this embodiment is a USBL (Ultra Short Base Line) type positioning system. For example, the acoustic positioning device 23 on the ship 2 has a transmitter and a receiving array. The transmitter sends sound waves, and the transponder 32, which detects the sound waves, sends a response wave to the acoustic positioning device 23. The acoustic positioning device 23 calculates the distance to the transponder 32 from the round-trip time of the sound waves between the receiving array and the transponder 32, and also determines the direction of the transponder 32 based on the phase difference of the sound waves that have reached each element in the receiving array.

[0024] It should be noted that the acoustic positioning system of this embodiment is not limited to a USBL-type positioning system. For example, the acoustic positioning device 23 may use an SBL (Short Base Line) system, in which three or more receivers are installed on the ship 2 spaced apart from each other, and the direction of the transponder 32 relative to the ship 2 is determined based on the difference in arrival times of the response waves received by these receivers.

[0025] Furthermore, as shown in Figure 2, the underwater docking device 3 includes a thruster 33, at least one camera 34, a communication interface 35, a docking actuator 36, and a control device 37.

[0026] The thruster 33 generates thrust to move the body 31 of the underwater docking device 3 underwater. The thruster 33 can change the attitude, orientation, and direction of movement of the body 31 of the underwater docking device 3 underwater. In this embodiment, as shown in Figure 3, the thruster 33 includes, for example, one or more main thruster 33a for moving the body 31 forward, one or more vertical thrusters 33b for moving the body 31 up and down, and one or more horizontal thrusters 33c for moving the body 31 left and right. However, the thruster 33 may also include a rudder that changes the course of the underwater docking device 3 in addition to the multiple thrusters. The thruster 33 may also include, for example, a swivel thruster that can change the direction in which it generates thrust.

[0027] At least one camera 34 is a pressure-resistant camera for underwater photography and is used to image the AUV 4 underwater. In this embodiment, as will be described later, the underwater docking device 3 descends above the AUV 4 and docks with the AUV 4. For this reason, at least one camera 34 includes, for example, a camera facing downwards from the underwater docking device 3 so that docking can be performed while imaging the AUV 4. At least one camera 34 may also include, for example, a camera facing forwards from the underwater docking device 3.

[0028] The communication interface 35 is a device for communicating with the aforementioned communication interface 22 provided on the ship 2. As previously stated, communication between the ship 2 and the underwater docking device 3, that is, communication between the communication interface 22 on the ship 2 and the communication interface 35 on the underwater docking device 3, is conducted via a wire.

[0029] The docking actuator 36 is an actuator for docking and undocking the underwater docking device 3 and the AUV 4. The docking actuator 36 moves the engaging element of the underwater docking device 3 that can engage with the engaging element of the AUV 4. In this embodiment, the docking actuator 36 is, for example, an electric linear actuator including a motor, and moves the engaging element of the underwater docking device 3 linearly. The type of docking actuator 36 is not particularly limited. The docking actuator 36 does not have to be an electric linear actuator; it may be another type of actuator, such as a solenoid actuator or a pneumatic actuator. The docking actuator 36 may also be a rotary actuator. Details of docking and undocking using the docking actuator 36 will be described later.

[0030] The control device 37 controls various operations of the underwater docking device 3. For example, the control device 37 is configured to control the propeller 33 based on operation commands received from the ship 2 via the communication interface 35. In terms of hardware, the control device 37 includes, for example, a processor such as a CPU, and memory such as volatile memory and non-volatile memory. The control device 37 performs various processes by having the processor execute programs stored in the memory. The processor and memory included in the control device 37 are examples of processing circuits.

[0031] (Configuration of the AUV) Next, the configuration of the AUV4 will be described. As shown in Figure 3, the AUV4 has a body 41 with a built-in battery 42. The AUV4 automatically performs various tasks such as surveying, inspecting, repairing, and maintaining underwater. Also, as shown in Figure 2, the AUV4 is equipped with a control device 43, a propulsion system 44, an inertial navigation system 45, a speed measuring device 46, an acoustic positioning device 47, and an acoustic communication device 48.

[0032] The control device 43 controls various operations of the AUV 4. In terms of hardware, the control device 43 includes, for example, a processor, volatile memory, non-volatile memory, and an I / O interface. The processor executes a control program stored in memory, thereby performing various calculation processes to control various controlled objects.

[0033] The thrusters 44 generate thrust to move the body 41 of the AUV 4 underwater. The thrusters 44 can change the attitude, orientation, and direction of movement of the body 41 of the AUV 4 underwater. In this embodiment, the thrusters 44 include, for example, one or more main thrusters 41a for moving the body 41 forward, one or more vertical thrusters 41b for moving the body 41 vertically, and one or more horizontal thrusters 41c for moving the body 41 horizontally. However, in addition to the multiple thrusters, the thrusters 44 may also include a rudder that changes the course of the AUV 4. The thrusters 44 may also include, for example, a swivel thruster that can change the direction in which it generates thrust.

[0034] The Inertial Navigation System 45 (INS) detects the acceleration and attitude of the AUV 4. The Inertial Navigation System 45 includes an accelerometer that detects the acceleration in the direction in which each of the three mutually orthogonal axes extends, and a gyro sensor that detects the angular velocity around each of the three axes.

[0035] The speed measuring device 46 measures the speed of the AUV4. For example, the speed measuring device 46 is a Doppler Velocity Log (DVL). A Doppler Velocity Log is a device that radiates several acoustic beams onto the seabed and measures the ground velocity from the reflected or scattered waves from the seabed.

[0036] The control device 43 calculates the position, orientation, attitude, or any combination thereof of the AUV 4 in a geographic coordinate system (longitude, latitude, altitude) from the measured values ​​of the inertial navigation device 45 and the speed measuring device 46.

[0037] The acoustic positioning device 47 constitutes an acoustic positioning system that measures the relative position of the AUV 4 with respect to the transponder 32 of the underwater docking device 3. The positioning method by the acoustic positioning device 47 is the same as the positioning method by the acoustic positioning device 23 on the ship 2 side described above, so a description is omitted.

[0038] The acoustic communication device 48 communicates with the acoustic communication device 24, which will be described later and is installed on the ship 2, using sound. The acoustic positioning device 47 and the acoustic communication device 48 may be configured as a single unit or as separate units.

[0039] (Example of a docking mechanism) As shown in Figure 4, the underwater docking device 3 and the AUV 4 are docked with the body 31 of the underwater docking device 3 and the body 41 of the AUV 4 facing each other in the vertical direction. Engaging elements are positioned on the lower part of the body 31 of the underwater docking device 3 and the upper part of the body 41 of the AUV 4, and the underwater docking device 3 and the AUV 4 are docked by the engagement of these engaging elements. An example of a mechanism for docking the underwater docking device 3 and the AUV 4 will be explained with reference to Figure 5.

[0040] As shown in Figure 5, the body 41 of the AUV 4 has a projection 51 that protrudes upward from the upper surface of the body 41. The projection 51 is, for example, substantially cylindrical. The projection 51 is an engaging element on the AUV 4 side. The projection 51 of the AUV 4 has a locking hole 52 that penetrates horizontally.

[0041] The body 31 of the underwater docking device 3 has an insertion hole 61 that opens downwards. The insertion hole 61 is sized so that the projection 51 of the AUV 4 can enter when the underwater docking device 3 descends from directly above the AUV 4 while aligning itself with the AUV 4 in the water.

[0042] An opening 61a is formed in the side wall that constitutes the insertion hole 61 of the underwater docking device 3. A locking pin 62 is disposed on the body 31 so as to be able to pass through the opening 61a of the side wall that constitutes the insertion hole 61. The locking pin 62 is an engaging element on the underwater docking device 3 side. The locking pin 62 is moved by the docking actuator 36 and moves between the extended position and the retracted position. In FIG. 5, the locking pin 62 when in the extended position is shown by a solid line, and the locking pin 62 when in the retracted position is shown by a two-dot chain line. When the locking pin 62 is in the retracted position, the locking pin 62 does not protrude into the insertion hole 61. When the locking pin 62 is in the extended position, it protrudes horizontally into the insertion hole 61. When the locking pin 62 is moved from the retracted position to the extended position with the protrusion 51 inserted into the insertion hole 61, the locking pin 62 passes through the locking hole 52 of the protrusion 51. Thereby, the protrusion 51 is prevented from coming out of the insertion hole 61, and the underwater docking device 3 is in a docking state with the AUV 4.

[0043] In addition, although FIG. 5 shows one set of engaging elements on the underwater docking device 3 side and the AUV 4 side that engage with each other, the underwater docking device 3 and the AUV 4 may be docked with a plurality of sets of engaging elements. For example, the AUV 4 may have a plurality of protrusions 51, or the underwater docking device 3 may have the same number of a plurality of insertion holes 61 and a plurality of locking pins 62 as the protrusions 51 that the AUV 4 has. In this case, the underwater docking device 3 may include a plurality of docking actuators 36.

[0044] (Flow of AUV release) Before explaining the recovery flow in the recovery system 1A, the flow of AUV 4 release in water will be explained. First, on the ship 2, when the AUV 4 is not docked with the underwater docking device 3, the AUV 4 is docked with the underwater docking device 3.

[0045] The operator operates the take-up device 27 to pay out the cable 30 and make the underwater docking device 3 land on water. For example, the underwater docking device 3 in a state of being docked with the AUV 4 is made to land on water using a crane installed on the deck of the ship 2 or the like. After landing on water, the payout of the cable 30 is continued to sink the underwater docking device 3 in a state of being docked with the AUV 4 to a predetermined depth. When the underwater docking device 3 in a state of being docked with the AUV 4 reaches the predetermined depth, the operator operates the operation device 25 to send a docking release instruction to the underwater docking device 3. Whether the underwater docking device 3 has reached the predetermined depth may be determined from the measured value of a depth gauge provided in the underwater docking device 3 or the AUV 4.

[0046] In the underwater docking device 3 that has received the docking release instruction, the control device 37 controls the docking actuator 36 to perform a docking release operation. That is, the control device 37 controls the docking actuator 36 to move the locking pin 62 from the protruding position to the retracted position. Thus, the docking between the underwater docking device 3 and the AUV 4 is released.

[0047] After the docking is released, the operator sends a work start instruction from the acoustic communication device 24 to the acoustic communication device 48 of the AUV 4. After receiving the work start instruction, the AUV 4 executes a program stored in the memory of the control device 43 to start a predetermined underwater operation. After the AUV 4 heads for the underwater operation, the operator operates the take-up device 27 to wind up the cable 30 and recover the underwater docking device 3 to the ship 2.

[0048] (Flow of AUV recovery) Next, the flow until the AUV 4 is recovered to the ship 2 will be described. FIG. 6 is a flowchart showing the flow of recovering the AUV 4 to the ship 2 by the recovery system 1A of FIG. 1. Hereinafter, the flow of the recovery method will be described on the premise that the ship 2 stays on the water during the operation of the AUV 4.

[0049] [Moving the AUV to a docking-ready position: Step S1] When the control device 43 of the AUV 4 determines that the recovery start conditions have been met, it controls the thrusters 44 to move to the position where the AUV 4 is undocked from the underwater docking device 3. Hereinafter, the position where the AUV 4 is undocked from the underwater docking device 3 will be referred to as the "undocked position". For example, the control device 43 of the AUV 4 uses the measurements of the inertial navigation device 45 and the speed meter 46 to calculate how the AUV 4 has moved from the undocked position after it has been undocked from the underwater docking device 3, that is, the current position of the AUV 4 relative to the undocked position. The control device 43 uses the measurements of the inertial navigation device 45 and the speed meter 46 to control the thrusters 44 so that the AUV 4's own position reaches the undocked position.

[0050] The recovery initiation conditions are not particularly limited. For example, the recovery initiation condition may be that a recovery initiation instruction has been received from outside the AUV 4, such as from the operator interface device 20, via the acoustic communication device 48. Alternatively, the recovery initiation condition may be that the remaining charge of the battery 42 falls below a predetermined value.

[0051] [Moving the underwater docking device toward the AUV: Step S2] When the AUV 4 reaches the undocking position, the operator operates the winding device 27 to unwind the rope 30 and bring the underwater docking device 3 into the water. Then, the operator operates the control device 25 to move the underwater docking device 3 toward the AUV 4. That is, in the operator interface device 20, the control device 21 sends operation commands to the underwater docking device 3 via the communication interface 22, corresponding to the operator's operation of the control device 25. In the underwater docking device 3, the control device 37 controls the thrusters 33 based on the received operation commands.

[0052] When moving the underwater docking device 3 toward the AUV 4, relative position information indicating the relative position between the underwater docking device 3 and the AUV 4 is obtained by acoustic positioning. Specifically, the AUV 4 is equipped with a transponder that, together with the acoustic positioning device 23, constitutes an acoustic positioning system. The transponder of the AUV 4 detects sound waves from the acoustic positioning device 23 on the ship 2 side and sends a response wave back to the acoustic positioning device 23. The acoustic positioning device 23 on the ship 2 calculates the position of the AUV 4 relative to the ship 2 from the response wave received from the transponder of the AUV 4. The acoustic positioning device 23 on the ship 2 also calculates the position of the underwater docking device 3 relative to the ship 2 from the response wave received from the transponder 32 of the underwater docking device 3. Based on the position of the AUV 4 relative to the ship 2 and the position of the underwater docking device 3 relative to the ship 2, the acoustic positioning device 23 on the ship 2 side calculates the position of one of the AUV 4 and the underwater docking device 3 relative to the other. In this way, the operator interface device 20 acquires the relative position between the underwater docking device 3 and the AUV 4 in real time. Based on the relative position information indicating the relative position between the underwater docking device 3 and the AUV 4, the operator operates the control device 25 to bring the underwater docking device 3 closer to the AUV 4.

[0053] The method for acquiring relative position information indicating the relative position between the underwater docking device 3 and the AUV 4 is not limited to the method described above. For example, in the AUV 4, the acoustic positioning device 47 may calculate the relative position between the underwater docking device 3 and the AUV 4 by acoustic positioning with the transponder 32 of the underwater docking device 3. Alternatively, the control device 21 of the ship 2 may send position inquiry information from the acoustic communication device 24 to the acoustic communication device 48 of the AUV 4 in response to operator operations. In the AUV 4, upon receiving the position inquiry information, the control device 43 may send relative position information indicating the relative position between the underwater docking device 3 and the AUV 4 from the acoustic communication device 48 to the acoustic communication device 24 of the ship 2, thereby allowing the operator interface device 20 to acquire the relative position between the underwater docking device 3 and the AUV 4 in real time. In this case, the AUV 4 does not need to be equipped with a transponder.

[0054] The method by which the operator knows when the AUV 4 has reached the undocked position is not particularly limited. For example, when the AUV 4 reaches the undocked position, the control device 43 of the AUV 4 may control the acoustic communication device 48 to send an arrival signal to the acoustic communication device 24 of the ship 2. Alternatively, for example, if the AUV 4 is equipped with a transponder that detects sound waves from the acoustic positioning device 23 on the ship 2 and sends a response wave back to the acoustic positioning device 23, the acoustic positioning device 23 on the ship 2 may calculate the position of the AUV 4 relative to the ship 2, and the control device 21 may determine whether the position of the AUV 4 relative to the ship 2 has reached the undocked position and output the determination result.

[0055] Furthermore, in step S2, the operator does not need to operate the underwater docking device 3 toward the AUV 4. The control device 37 of the underwater docking device 3 may control the thrusters 33 based on relative position information indicating the relative position between the underwater docking device 3 and the AUV 4, thereby bringing the underwater docking device 3 closer to the AUV 4.

[0056] [Docking operation: Step S3] While the underwater docking device 3 is being moved to the AUV 4, the control device 37 in the underwater docking device 3 sends images captured by the camera 34 from the underwater docking device 3 to the operator interface device 20 via the communication interface 35. In the operator interface device 20, the control device 21 displays the received images on the display 26.

[0057] When the AUV 4 enters the camera's imaging range, the operator operates the control device 25 while viewing the image of the AUV 4 displayed on the display 26 to move the underwater docking device 3 so that it docks with the AUV 4.

[0058] In this embodiment, the underwater docking device 3 is positioned in a predetermined orientation to match the predetermined orientation of the AUV 4, and the underwater docking device 3 is lowered from above the AUV 4 to insert the projection 51 of the AUV 4 into the insertion hole 61 of the underwater docking device 3. Subsequently, in the operator interface device 20, the control device 21 sends a docking command from the operator interface device 20 to the underwater docking device 3 via the communication interface 22 in response to the operator's operation. In the underwater docking device 3, the control device 37 controls the docking actuator 36 to move the locking pin 62 from the submerged position to the extended position based on the received docking command. In this way, docking between the underwater docking device 3 and the AUV 4 is completed.

[0059] Furthermore, the transmission of images captured by the camera 34 from the underwater docking device 3 to the operator interface device 20 may be started at the timing when it is necessary to align the underwater docking device 3 with the AUV for docking, or it may be started after the underwater docking device 3 has reached a predetermined distance from the AUV 4.

[0060] [Cable winding: Step S4] Once the docking of the underwater docking device 3 with the AUV 4 is complete, the control device 21 operates the winding device 27 in response to the operator's input and winds up the cable 30. In this way, the underwater docking device 3, which is docked with the AUV 4, is recovered by the ship 2.

[0061] (Effects) As described above, according to the recovery system 1A of this embodiment, the operator operates the underwater docking device 3 to dock with the AUV 4 while viewing the AUV 4 displayed on the display 26. Therefore, compared to the case where the AUV 4 approaches the underwater docking device and docks using an automatic driving program, docking between the AUV 4 and the underwater docking device 3 can be performed in a shorter time, and as a result, the time required to recover the AUV 4 can be shortened.

[0062] To explain in more detail, in conventional docking methods in which an AUV approaches and docks with an underwater docking device, the AUV needs to have various operation programs associated with docking, such as tracking the underwater docking device floating in the water, precise positioning relative to the underwater docking device, movement of the AUV to dock with the underwater docking device, and operation of the docking device, and it also needs to have the energy required for the movement during docking. In contrast, in this embodiment, the operator operates the underwater docking device 3 to dock with the AUV 4 while viewing the AUV 4 displayed on the display 26, so the AUV 4 only needs to have the function of hovering in a predetermined place, docking can be performed in a short time by operator operation, and the power consumption of the AUV required for docking can be reduced.

[0063] <Second Embodiment> Figure 7 is a schematic diagram of the recovery system 1B according to the second embodiment. Figure 8 is a block diagram showing the configuration of the recovery system 1B in Figure 7. In the first embodiment, the operator operating the underwater docking device 3 was on the ship 2, but in this embodiment, the operator operating the underwater docking device 3 is not on the ship 2 but on land. In other words, in this embodiment, the operator interface device 70 is located on land, not on the ship 2. In the recovery system 1B of this embodiment, the configuration of the underwater docking device 3 and the AUV 4 is the same as in the first embodiment, so the explanation of the underwater docking device 3 and the AUV 4 is omitted.

[0064] As shown in Figure 8, the operator interface device 70 includes a control device 71, a communication device 72, an operating device 73, and a display 74. The ship 2 includes a control device 21, a communication interface 22, an acoustic positioning device 23, an acoustic communication device 24, and a communication device 28.

[0065] The control device 71 has, in terms of hardware, a processor such as a CPU, and memory such as volatile memory and non-volatile memory. The control device 71 performs various processes by having the processor execute programs stored in memory. The land-side communication device 72 is capable of communicating with the ship-side communication device 28 via the communication satellite S. The operating device 73 receives input from the operator. The operating device 73 is the same as the operating device 25, so its description is omitted. The display 74 is also the same as the display 26, so its description is omitted.

[0066] In this embodiment, the operator interface device 70 communicates with the AUV 4 and the underwater docking device 3 via the ship 2. In step S3 above, for example, the control device 37 sends images from the underwater docking device 3 to the ship 2 via wired connection, and the control device 21 on the ship 2 sends images from the ship 2 to the operator interface device 70 via satellite communication. For example, the control device 71 of the operator interface device 70 sends operation commands from the operator interface device 70 to the ship 2 via satellite communication, and the control device 21 on the ship 2 sends operation commands from the ship 2 to the underwater docking device 3 via wired connection. Docking commands and the like are handled similarly.

[0067] In this embodiment, the same effects as in the first embodiment can be obtained. Furthermore, in this embodiment, even when an operator is not on board, the underwater docking device 3 can be moved to dock with the AUV 4 by the operator's operation.

[0068] <Other Embodiments> This disclosure is not limited to the embodiments described above, and their configurations may be modified, added to, or deleted.

[0069] In the first and second embodiments described above, the ship 2 was a surface vessel that navigated or was moored on the water, but the ship that recovers the AUV does not have to be a surface vessel. For example, Figure 9 shows a schematic configuration diagram of a system 1C for recovering an AUV 4 with a submersible 2C, which is a type of ship. As shown in Figure 9, for example, the ship that recovers the AUV may be a submersible 2C configured to be submersible. The submersible 2C may be a manned or unmanned submersible. The submersible 2C may or may not have a housing section 101 for housing the underwater docking device 3 docked to the AUV 4 as shown in Figure 9. In other words, the recovery method for the AUV is not limited to lifting the AUV onto the water and recovering it with a surface vessel, but may also be a method of recovering the AUV underwater, either inside or outside the ship.

[0070] Figure 6 shows an example of a method for recovering an AUV onto a ship, but the recovery method is not limited to that shown in Figure 6. For example, in the recovery method shown in Figure 6, while the AUV 4 is working underwater, ship 2 remains on the water and recovers the AUV 4 at the same location where it was released. However, ship 2 may recover the AUV 4 at a different location from where it was released.

[0071] For example, if the work performed by AUV4 underwater is to inspect a subsea pipeline laid on the seabed for, say, tens or hundreds of kilometers, AUV4 will inspect the pipeline while navigating along it. In this case, multiple recovery locations along the subsea pipeline may be predetermined. Specifically, ship 2 is equipped with a GPS (Global Positioning System) receiver to acquire ship position information at sea, and while AUV4 is navigating along the subsea pipeline, ship 2,2C may navigate along the subsea pipeline until it reaches the predetermined recovery location for the next AUV4. Multiple recovery locations scattered along the subsea pipeline on a map may be stored in advance, for example, in the memory of the control device 21. Since the speed of ship 2,2C is usually greater than the speed of AUV4, ship 2,2C may remain stationary after reaching a recovery location until AUV4 reaches the recovery location.

[0072] When the AUV4 is navigating along the subsea pipeline in this manner, in step S1 of Figure 6, instead of moving the AUV4 to the undocked position, the AUV4 may be brought to the surface at the planned recovery location on the map, within reach of the underwater docking device 3.

[0073] Alternatively, in step S1 of Figure 6, if it is possible to lower the underwater docking device 3 to the depth where the seabed pipeline is located or near it, the underwater docking device 3 may be kept waiting at a depth close to the seabed pipeline at the planned recovery location on the map. Since the AUV 4 travels along the seabed pipeline, keeping the underwater docking device 3 waiting along the seabed pipeline allows the AUV 4 to move closer to the underwater docking device 3. After the AUV 4 reaches the planned recovery location and stops, the operator may operate the underwater docking device 3 to move toward the AUV 4.

[0074] The mechanism for docking the AUV 4 and the underwater docking device 3 is not limited to the one shown in Figure 5 and can be modified as appropriate. Figure 10 is a schematic diagram showing a modified docking mechanism for docking the AUV 4 and the underwater docking device 3.

[0075] As shown in Figure 10, the body 41 of the AUV 4 has a projection 81 that protrudes upward from the upper surface of the body 41. The projection 81 has a substantially cylindrical shaft portion 81a that extends upward from the upper surface of the body 41, and a substantially frustoconical locking portion 81b connected to the upper end of the shaft portion 81a. The diameter of the locking portion 81b decreases as it extends upward. That is, the outer circumferential surface of the locking portion 81b is tapered. The diameter of the lower part of the locking portion 81b is larger than the diameter of the shaft portion 81a.

[0076] The body 31 of the underwater docking device 3 has an insertion hole 91 that opens downwards. The insertion hole 91 is sized so that the projection 81 of the AUV 4 can enter when the underwater docking device 3 descends from directly above the AUV 4 in the water.

[0077] An opening 91a is formed in the side wall that constitutes the insertion hole 91 of the underwater docking device 3. The body 31 is equipped with a locking member 92 positioned in the insertion hole 91, a biasing member 93 that passes through the opening 91a, and a receiving portion 94 that supports the biasing member 93. The biasing member 93 biases the locking member 92 toward the center of the insertion hole 91. The receiving portion 94 may be a member fixed to the body 41, or a part of the body 41.

[0078] As the underwater docking device 3 descends from directly above the AUV 4 underwater, the upper end of the projection 81 of the AUV 4 reaches the entrance of the insertion hole 91, and the tapered outer surface of the locking portion 81b presses the locking member 92 radially outward against the biasing force of the biasing member 93. As the underwater docking device 3 descends further and the locking member 92 moves over the lower part of the locking portion 81b, the pressure on the locking member 92 by the outer surface of the locking portion 81b is released, and the locking member 92 moves radially inward below the locking portion 81b due to the biasing force of the biasing member 93. In this way, the projection 81 is prevented from coming out of the insertion hole 91, and the underwater docking device 3 is docked with the AUV 4.

[0079] Furthermore, in the examples of Figures 5 and 10, the underwater docking device had an insertion hole and the AUV had a projection, but the underwater docking device may have a projection and the AUV may have an insertion hole. In this case, the docking actuator may engage an engaging element, which rotates integrally with the projection, with the engaging element on the AUV side by rotating the projection. Moreover, the docking mechanism is not limited to a configuration in which one of the underwater docking device and the AUV has a projection and the other has an insertion hole. For example, the docking mechanism may be configured in which one of the underwater docking device and the AUV has a hook and the other has a fitting that can engage with the hook.

[0080] In the first and second embodiments described above, the underwater docking device 3 was docked to the AUV 4 by lowering it toward the AUV 4, but the docking method is not limited to this. For example, the underwater docking device 3 may be docked to the AUV 4 by moving it horizontally toward the AUV 4. The parts that constitute the docking mechanism between the AUV and the underwater docking device (such as the position of the protrusion on the AUV side and the position of the insertion hole on the underwater docking device side) can also be changed as appropriate.

[0081] The elements provided by the operator interface device, the vessel, the underwater docking device, and the AUV are not limited to those described in the first and second embodiments above. The underwater docking device may include a power supply device, and the AUV may include a power receiving device.

[0082] As described above, the embodiments have been explained as examples of the technology disclosed in this application. However, the technology in this disclosure is not limited to these embodiments and can be applied to embodiments that have been modified, replaced, added, or omitted as appropriate. It is also possible to combine the components described in the embodiments to create new embodiments. For example, some components or methods in one embodiment may be applied to other embodiments, and some components in an embodiment can be separated from other components in that embodiment and extracted as appropriate. In addition, the components described in the attached drawings and detailed description include not only components that are essential for solving the problem, but also components that are not essential for solving the problem, in order to illustrate the technology. The two blocks shown in order in the flowchart may be executed simultaneously or in reverse order, depending on the circumstances.

[0083] 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), FPGAs (Field Programmable Gate Arrays), 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, 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.

[0084] The recovery program may be stored on a computer-readable storage medium. The storage medium is a non-temporary, tangible medium. The storage medium may be built into or attached to a computer (e.g., a personal computer, a mobile information terminal, a server, etc.). The storage medium may include RAM, ROM, EEPROM, storage, etc., and may be, for example, a hard disk, flash memory, an optical disc, etc. The program stored on the storage medium may be executed on a computer to which the storage medium is directly connected, or on a computer connected to the storage medium via a communication network (e.g., the Internet).

[0085] Each of the following embodiments is a disclosure of a preferred embodiment.

[0086] [Aspect 1] A recovery system comprising: an operator interface device including an operating device and a display for receiving operator input; an underwater docking device connected to a ship by a rope, including a camera and a propeller; and an autonomous underwater vehicle configured to be dockable with the underwater docking device, wherein a recovery method for recovering the autonomous underwater vehicle on the ship comprises: sending an image of the autonomous underwater vehicle underwater captured by the camera from the underwater docking device to the operator interface device; displaying the image on the display; sending an operation command from the operator interface device to the underwater docking device in response to the operator input; operating the propeller based on the operation command to dock the underwater docking device with the autonomous underwater vehicle; and recovering the underwater docking device docked with the autonomous underwater vehicle on the ship by pulling in the rope on the ship.

[0087] According to Embodiment 1, the operator operates the underwater docking device to dock with the autonomous underwater vehicle while viewing the autonomous underwater vehicle displayed on the screen. Therefore, compared to the case where the autonomous underwater vehicle docks with an underwater station using an automatic driving program, docking between the autonomous underwater vehicle and the underwater docking device can be performed in a shorter time, and as a result, the time required to recover the autonomous underwater vehicle can be shortened.

[0088] [Aspect 2] A recovery method for an autonomous underwater vehicle according to aspect 1, wherein relative position information indicating the relative position between the underwater docking device and the autonomous underwater vehicle is acquired by acoustic positioning, and the underwater docking device is moved toward the autonomous underwater vehicle using the relative position information before docking the underwater docking device with the autonomous underwater vehicle.

[0089] According to embodiment 2, the underwater docking device can be moved to a position where the autonomous unmanned submersible can be imaged by the camera.

[0090] [Aspect 3] The recovery method for an autonomous underwater vehicle according to aspect 1 or 2, wherein the vessel is a different submersible from the autonomous underwater vehicle, and is configured to recover the underwater docking device when it is docked to the autonomous underwater vehicle.

[0091] According to embodiment 3, an autonomous unmanned submersible can be recovered underwater.

[0092] [Aspect 4] A recovery method for an autonomous underwater vehicle according to aspect 1 or 2, wherein the operator interface device is located on land, and sending the image from the underwater docking device to the operator interface device includes sending the image from the underwater docking device to the ship by wire and sending the image from the ship to the operator interface device by satellite communication, and sending the operation command from the operator interface device to the underwater docking device includes sending the operation command from the operator interface device to the ship by satellite communication and sending the operation command from the ship to the underwater docking device by wire.

[0093] According to embodiment 4, even when an operator is not on board, the underwater docking device can be moved by the operator to dock with the autonomous unmanned submersible.

[0094] [Aspect 5] An underwater docking device configured to dock with an autonomous underwater vehicle in water, comprising: a body connected by a rope to a ship located on or underwater; a propulsion system disposed on the body; a communication interface configured to communicate with the ship; a camera mounted on the body; and a processing circuit configured to control the propulsion system based on operation commands received from the ship via the communication interface.

[0095] According to embodiment 5, the underwater docking device can be moved in response to an operation command to dock with the autonomous underwater vehicle. Therefore, compared to the case where the autonomous underwater vehicle docks with an underwater station using an automatic driving program, docking between the autonomous underwater vehicle and the underwater docking device can be performed in a shorter time, and as a result, the time required to recover the autonomous underwater vehicle can be shortened.

[0096] 2,2C: Ship 3: Underwater docking device 20: Operator interface device 25: Control device 26: Display 31: Body 33: Propulsion 34: Camera 35: Communication interface 37: Control device 70: Operator interface device 71: Control device 72: Communication device 73: Control device 74: Display

Claims

1. A recovery system comprising: an operator interface device including an operating device and a display for receiving operator input; an underwater docking device connected to a ship by a cable, including a camera and a propeller; and an autonomous underwater vehicle configured to be dockable with the underwater docking device, wherein the recovery method for recovering the autonomous underwater vehicle on the ship is as follows: sending an image of the autonomous underwater vehicle taken underwater by the camera from the underwater docking device to the operator interface device; displaying the image on the display; sending an operation command from the operator interface device to the underwater docking device in response to the operator input; operating the propeller based on the operation command to dock the underwater docking device with the autonomous underwater vehicle; and recovering the underwater docking device docked with the autonomous underwater vehicle on the ship by pulling in the cable on the ship.

2. A recovery method for an autonomous underwater vehicle according to claim 1, comprising: acquiring relative position information indicating the relative position between the underwater docking device and the autonomous underwater vehicle by acoustic positioning; and, before docking the underwater docking device with the autonomous underwater vehicle, using the relative position information to move the underwater docking device toward the autonomous underwater vehicle.

3. The recovery method for an autonomous underwater vehicle according to claim 1 or 2, wherein the vessel is a different submersible vehicle from the autonomous underwater vehicle, configured to recover the underwater docking device when it is docked to the autonomous underwater vehicle.

4. The recovery method for an autonomous underwater vehicle according to claim 1 or 2, wherein the operator interface device is located on land, and sending the image from the underwater docking device to the operator interface device includes sending the image from the underwater docking device to the ship by wire and sending the image from the ship to the operator interface device by satellite communication, and sending the operation command from the operator interface device to the underwater docking device includes sending the operation command from the operator interface device to the ship by satellite communication and sending the operation command from the ship to the underwater docking device by wire.

5. An underwater docking device configured to dock with an autonomous underwater vehicle in water, comprising: a body connected by a cable to a ship located on or underwater; a propulsion system disposed on the body; a communication interface configured to communicate with the ship; a camera mounted on the body; and a processing circuit configured to control the propulsion system based on operation commands received from the ship via the communication interface.

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