Self-position estimation error correction method and system for underwater vehicle

Abstract

To correct error occurring with an own position estimation value and to have an underwater sailing body approach a target with high accuracy.SOLUTION: The own position estimation error compensation method: has an underwater sailing body 100 loaded with detection means for detecting a target object 400 and own position estimation means 18 set a position of the target object 400 and approach the target 400; acquires detection data detecting the target 400 by the detection means; transmits the detection data to monitoring means 302 by wireless communication; monitors a position error between the target 400 and the underwater sailing body 100 based on the detection data in the monitoring means 302; and carries out a process for solving a positional error due to an estimation error in the own position in the own position estimation means 18 by operation means 48 when the positional error exists.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for correcting an error in estimating a self-location of an underwater vehicle and a system for correcting an error in estimating a self-location of an underwater vehicle. [Background technology]

[0002] In recent years, the bottom of the ocean and other bodies of water have been attracting attention as a source of various resources, including mineral resources. Accordingly, the need for bottom surveys is also increasing. Remote sensing techniques using signals such as sound waves, lasers, and visible light are generally used to survey the bottom of the water. However, since these signals have propagation losses, high resolution and high accuracy information can be obtained by using them as close to the bottom as possible. Therefore, there is a need for technology to navigate underwater vehicles (e.g., submersibles) near the bottom of the water in a desired trajectory and attitude.

[0003] A technology has been disclosed in which a buoy connected to an underwater exploration submersible robot is floated on the water surface, and the navigation of the underwater exploration submersible robot is controlled based on the position of the buoy (Patent Document 1).A technology has been disclosed in which a surface robot connected to an underwater robot that travels underwater is floated on the water surface, and the position of the underwater robot is controlled via the surface robot (Patent Document 2).

[0004] Also, a technology has been disclosed for an underwater robot control system that includes an underwater robot that navigates underwater and multiple communication buoys that float on the water surface and communicate with the underwater robot, in which the underwater position of the underwater robot is calculated by communicating with three or more communication buoys (Patent Document 3). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2019 / 181750 [Patent Document 2] Special Publication No. 2018-514433 [Patent Document 3] JP 2018-203192 A Summary of the Invention [Problem to be solved by the invention]

[0006] In order for an underwater vehicle to navigate autonomously, it is important to estimate its own position underwater. However, when estimating its own position using an internal device of the underwater vehicle, such as an inertial navigation system, errors often accumulate in the estimated self-position value as the vehicle navigates, which becomes an obstacle to high-precision position control during autonomous navigation.

[0007] The present invention aims to provide a self-position estimation error correction method and a self-position estimation error correction system for an underwater vehicle that achieves autonomous navigation with high-precision position control by correcting errors in self-position estimation using information acquired by the underwater vehicle. [Means for solving the problem]

[0008] A method for correcting self-position estimation errors for an underwater vehicle corresponding to claim 1 includes the steps of: setting the position of a target on an underwater vehicle equipped with a detection means for detecting a target and a self-position estimation means, sailing the underwater vehicle toward the target, acquiring detection data of the target detected by the detection means, transmitting the detection data to a monitoring means using wireless communication, monitoring a positional error between the target and the underwater vehicle based on the detection data in the monitoring means, and performing processing by an operation means to eliminate the positional error caused by an error in the estimation of the self-position by the self-position estimation means if a positional error exists.

[0009] Here, the detection means is an imaging means which acquires imaging data of an image as the detection data, and it is preferable that the detection means monitors an image based on the imaging data which is displayed on an image display means provided in the monitoring means, and when there is a positional error between the target and the underwater vehicle, the positional error is eliminated while monitoring the image by operating the operating means.

[0010] Furthermore, when the target is within the screen of the image display means, it is preferable to eliminate the positional error while monitoring the screen by operating the operating means.

[0011] It is also preferable to recognize the distance and direction between the target and the underwater vehicle in real time, and to eliminate the positional error by operating the operating means.

[0012] It is also preferable that the detection data be transmitted to a buoy means located on the water surface by underwater wired communication, and that the detection data be further transmitted from the buoy means to the monitoring means by using radio waves as the wireless communication.

[0013] It is also preferable that the underwater vehicle is equipped with a position measuring means, transmits relative position information with respect to the target to the monitoring means, and utilizes the position information when eliminating the position error by the operating means.

[0014] It is also preferable that a plurality of the detection means are provided, each of which also serves as the position measurement means, and obtains the position information simultaneously with the detection.

[0015] It is also preferable that a waypoint is set for the underwater vehicle, and the underwater vehicle is caused to navigate toward the waypoint using the self-position estimation means.

[0016] It is also preferable that the position of the underwater vehicle which is estimated to have reached the waypoint is determined from the monitoring means, and the position of the underwater vehicle is corrected based on instructions from the monitoring means in accordance with the results of the positioning.

[0017] It is also preferable that the result of eliminating the positional error by the operation means is utilized to correct the self-position estimation means.

[0018] The self-position estimation error correction system for an underwater vehicle corresponding to claim 11 comprises the underwater vehicle equipped with a detection means for detecting a target and a self-position estimation means, a position setting means for setting the position of the target in the underwater vehicle, a monitoring means having an operation means for operating the underwater vehicle, a wireless communication means for transmitting detection data of the target detected by the detection means to the monitoring means, and a linking means that, when there is a positional error between the target and the underwater vehicle, enables the positional error of the underwater vehicle caused by an error in the estimation of its own position by the self-position estimation means to be eliminated by operating the operation means while monitoring based on the detection data.

[0019] Here, it is preferable that the detection means is an imaging means which acquires imaging data of an image as the detection data, and the linking means monitors an image based on the imaging data which is displayed on an image display means provided in the monitoring means, and makes it possible to eliminate the positional error while monitoring the image using the operation means when there is a positional error between the target and the underwater vehicle.

[0020] It is also preferable that when the target is within the screen of the image display means, the positional error can be eliminated while monitoring the screen by the operation means.

[0021] It is also preferable that the distance and direction between the target and the underwater vehicle are recognized in real time, and the positional error is eliminated by the operating means.

[0022] It is also preferable to further provide a buoy means for facing the water surface and a signal cable connecting the underwater vehicle and the buoy means, wherein the detection data is transmitted to the buoy means by underwater wired communication via the signal cable, and the detection data is transmitted from the buoy means to the monitoring means using radio waves via the wireless communication means.

[0023] It is also preferable that the underwater vehicle has a position measuring means, and that relative position information with respect to the target obtained by the position measuring means is transmitted to the monitoring means, and that the position information is utilized when eliminating the positional error by the operating means.

[0024] It is also preferable that a plurality of the detection means are provided, each of which also serves as the position measurement means, and obtains the position information simultaneously with the detection.

[0025] It is also preferable to provide the underwater vehicle with a memory means for storing waypoints previously set by the position setting means, and to navigate the underwater vehicle toward the target using the self-position estimation means in accordance with the stored waypoints.

[0026] It is also preferable that the monitoring means is provided with a positioning means for determining the position of the underwater vehicle, the position of the underwater vehicle which is estimated to have reached the waypoint is determined by the positioning means, and the position of the underwater vehicle is corrected by issuing an instruction from the monitoring means in accordance with the results of the positioning.

[0027] It is also preferable that the vehicle further comprises error correction means for utilizing the result of eliminating the positional error by the operation means to correct the self-position estimation means.

[0028] It is also preferable that the self-position estimation means has at least one of an inertial navigation system, a Doppler speedometer, and a depth meter. Effect of the Invention

[0029] According to the method for correcting self-position estimation error of an underwater vehicle corresponding to claim 1, the underwater vehicle equipped with a detection means for detecting a target and a self-position estimation means is caused to approach the target by setting the position of the target and traveling to the target, the detection means acquires detection data of the target, the detection data is transmitted to a monitoring means by wireless communication, the monitoring means monitors a position error between the target and the underwater vehicle based on the detection data, and when the position error is present, the operation means performs a process of eliminating the position error caused by the error in the estimation of the self-position by the self-position estimation means, thereby making it possible to improve the accuracy and efficiency of monitoring by eliminating the error in the estimation of the self-position of the underwater vehicle during autonomous traveling while monitoring the position error. Also, since the detection data can be transmitted wirelessly from the underwater vehicle to the monitoring means, the underwater vehicle can travel freely and monitoring can be performed efficiently over a wide area.

[0030] Here, the detection means is an imaging means which acquires imaging data of an image as the detection data, and monitors an image based on the imaging data displayed on an image display means provided in the monitoring means. If there is a positional error between the target and the underwater vehicle, the positional error is eliminated while monitoring the image by operating the operating means, thereby enabling the underwater vehicle to be moved to the correct position with high precision based on the imaging data of the image that was actually captured.

[0031] Furthermore, when the target is within the screen of the image display means, the positional error can be eliminated while monitoring the screen by operating the operating means, thereby allowing the underwater vehicle to be moved with high precision toward the target displayed on the screen and positioned correctly.

[0032] In addition, by recognizing the distance and direction between the target and the underwater vehicle in real time and eliminating the positional error by operating the operating means, the underwater vehicle can be moved with high precision in real time relative to the target displayed on the screen.

[0033] In addition, by transmitting the detection data to a buoy means on the water surface via underwater wired communication, and then transmitting the detection data from the buoy means to the monitoring means using radio waves as the wireless communication, it is possible to increase the speed and capacity of underwater communication through wired communication, while preventing the communication range in the air from being limited by wireless communication, thereby increasing the freedom of the underwater vehicle.

[0034] In addition, the underwater vehicle is equipped with a position measurement means, which transmits relative position information with respect to the target to the monitoring means, and the position information is also used when eliminating the positional error by the operating means, so that the movement of the underwater vehicle can be controlled according to the actually measured relative distance between the underwater vehicle and the target.

[0035] In addition, by providing multiple detection means that also serve as the position measurement means and acquiring the position information simultaneously with the detection, it is possible to simply control the movement of the underwater vehicle in accordance with the actual measured relative distance between the underwater vehicle and a target using stereoscopic images, etc.

[0036] Furthermore, by setting a waypoint for the underwater vehicle and using the self-position estimation means to navigate the underwater vehicle toward the waypoint, the underwater vehicle can be made to navigate autonomously along the waypoint and approach a target while correcting any positional errors resulting therefrom.

[0037] In addition, the position of the underwater vehicle that is estimated to have reached the waypoint is determined from the monitoring means, and the position of the underwater vehicle is corrected based on the positioning results by instructions from the monitoring means, so that the underwater vehicle can be navigated in a manner that reduces positional errors based on the positioning by the monitoring means.

[0038] Furthermore, by utilizing the results of eliminating the positional error by the operating means to correct the self-position estimation means, the accuracy of the self-position estimation means of the underwater vehicle can be improved based on the results of eliminating the positional error, allowing the underwater vehicle to navigate.

[0039] According to the self-position estimation error correction system for an underwater vehicle corresponding to claim 11, the underwater vehicle is equipped with a detection means for detecting a target and a self-position estimation means, a position setting means for setting the position of the target on the underwater vehicle, a monitoring means having an operation means for operating the underwater vehicle, a wireless communication means for transmitting detection data of the target detected by the detection means to the monitoring means, and a linking means for enabling, when there is a positional error between the target and the underwater vehicle, the positional error of the underwater vehicle caused by an error in the estimation of the self-position by the self-position estimation means to be eliminated by operating the operation means while monitoring based on the detection data, thereby improving the accuracy and efficiency of monitoring by monitoring the error in the estimation of the self-position of the underwater vehicle during autonomous traveling by the linking means and eliminating it by operating the operation means. Also, since the detection data can be transmitted wirelessly from the underwater vehicle to the monitoring means, the underwater vehicle can navigate freely and monitoring with good work efficiency can be performed over a wide area.

[0040] Here, the detection means is an imaging means which acquires imaging data of an image as the detection data, and the linking means monitors an image based on the imaging data displayed on an image display means provided in the monitoring means, and makes it possible to eliminate the positional error while monitoring the image using the operation means when there is a positional error between the target and the underwater vehicle, thereby enabling the underwater vehicle to be moved to the correct position with high precision based on the imaging data of the image that was actually captured.

[0041] Furthermore, when the target is within the screen of the image display means, it is possible to eliminate the positional error while monitoring the screen using the operation means, thereby making it possible to move the underwater vehicle with high precision relative to the target displayed on the screen.

[0042] In addition, by recognizing the distance and direction between the target and the underwater vehicle in real time and eliminating the positional error using the operating means, the underwater vehicle can be moved with high precision in real time relative to the target displayed on the screen.

[0043] The device further includes a buoy means for facing the water surface and a signal cable connecting the underwater vehicle and the buoy means, and the detection data is transmitted to the buoy means by underwater wired communication via the signal cable, and the detection data is transmitted from the buoy means to the monitoring means using radio waves via the wireless communication means, thereby increasing the speed and capacity of underwater communication through wired communication, and preventing the communication range in the air from being limited by wireless communication, thereby increasing the freedom of the underwater vehicle.

[0044] In addition, the underwater vehicle has a position measurement means, and relative position information between the underwater vehicle and the target obtained by the position measurement means is transmitted to the monitoring means. By also using the position information when eliminating the positional error by the operating means, the movement of the underwater vehicle can be controlled according to the actually measured relative distance between the underwater vehicle and the target.

[0045] In addition, by providing multiple detection means that also serve as the position measurement means and acquiring the position information simultaneously with the detection, it is possible to simply control the movement of the underwater vehicle in accordance with the actual measured relative distance between the underwater vehicle and a target using stereoscopic images, etc.

[0046] In addition, the underwater vehicle can be provided with a memory means for storing waypoints that have been preset by the position setting means, and the underwater vehicle can be caused to navigate toward the target using the self-position estimation means in accordance with the stored waypoints, thereby making it possible to cause the underwater vehicle to navigate autonomously along the waypoints and approach the target while correcting any position errors resulting from this.

[0047] In addition, the monitoring means can be provided with a positioning means for measuring the position of the underwater vehicle, and the position of the underwater vehicle that is estimated to have reached the waypoint can be measured by the positioning means, and the monitoring means can issue an instruction to correct the position of the underwater vehicle in accordance with the results of the positioning, thereby allowing the underwater vehicle to navigate in a manner that reduces positional errors based on the positioning by the monitoring means.

[0048] In addition, by further providing an error correction means that utilizes the result of eliminating the positional error by the operation means to correct the self-position estimation means, the error correction means can improve the accuracy of the self-position estimation means of the underwater vehicle based on the result of eliminating the positional error, allowing the underwater vehicle to navigate.

[0049] Furthermore, the self-position estimation means has at least one of an inertial navigation system, a Doppler speedometer, and a depth meter, and can estimate the self-position of the underwater vehicle using these devices. [Brief description of the drawings]

[0050] [Figure 1] 1 is a conceptual diagram illustrating the configuration of a self-position estimation error correction system for an underwater vehicle according to an embodiment of the present invention. [Diagram 2] 1 is a conceptual diagram illustrating a method for inspecting a target using an underwater vehicle in an embodiment of the present invention. FIG. [Diagram 3] 1 is a configuration block diagram of an underwater vehicle according to an embodiment of the present invention. [Figure 4] FIG. 2 is a configuration block diagram of a relay buoy in an embodiment of the present invention. [Diagram 5] FIG. 2 is a configuration block diagram of a terminal ship according to an embodiment of the present invention. [Figure 6] 5A to 5C are diagrams illustrating the movement control of an underwater vehicle based on captured images in an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0051] <Self-position estimation error correction system for underwater vehicles> The self-position estimation error correction system for an underwater vehicle in the embodiment of the present invention includes an underwater vehicle 100, a relay buoy 200, and a base ship 300, as shown in FIG.

[0052] As shown in Fig. 2, the underwater vehicle 100 is used to autonomously navigate underwater and inspect an inspection target such as a submarine cable. The use range of the underwater vehicle 100 is not limited to underwater, and it may be used in rivers, lakes, ponds, marshes, artificial pools, etc. The relay buoy 200 is used to relay communication between the underwater vehicle 100 and the base ship 300. The base ship 300 is used with a monitoring means for receiving information related to the inspection from the underwater vehicle 100 and for providing the underwater vehicle 100 with information for autonomous navigation and eliminating positional errors.

[0053] In this embodiment, the base ship 300 is used, but is not limited to a ship. It may be a base station located on land, or an underwater mother ship located underwater. It may be an aircraft flying in the air. In particular, in the case of an underwater mother ship placed underwater, for example, the underwater mother ship may be placed near the water surface and communicate with the relay buoy 200 using radio waves from an antenna facing the air, or it may be placed completely underwater and directly communicate with the relay buoy 200 and the underwater vehicle 100 using optical communication, thereby making it possible to acquire information (imaging data) related to images and videos.

[0054] <Configuration of the underwater vehicle> As shown in the conceptual configuration diagram of Fig. 3, an underwater vehicle 100 in an embodiment of the present invention includes a boat hull 10, a navigation means 12, an inspection means 14, an imaging means 16, a self-position estimation means 18, an error correction means 20, a storage means 22, a position setting means 24, and a communication means 26. The underwater vehicle 100 is, for example, an autonomous underwater vehicle (AUV), but is not limited to this.

[0055] The hull 10 is a sealable structure that defines a space such as a cabin, etc. The hull 10 is made of metal, reinforced plastic, etc., and also serves to mechanically support the components of the underwater vehicle 100.

[0056] The propulsion means 12 is a component that generates driving force for propelling the hull 10 and turns (swivels) the hull 10 in the vertical and horizontal directions. The propulsion means 12 is configured to include, for example, a main propulsion drive motor, a propeller, a rotating shaft, etc. as mechanisms for generating driving force. The main propulsion drive motor is a motor for providing driving force to the hull 10. The main propulsion drive motor uses power from a battery to rotate the rotating shaft of the propulsion means 12 at a rotation speed and torque according to a drive control signal. This rotates the propeller connected to the drive shaft, providing propulsive force to the hull 10.

[0057] The propulsion means 12 also includes, for example, a rudder for turning (spinning) the hull 10 in the up, down, left and right directions. The hull 10 can be turned left or right by tilting the vertical rudder right or left with respect to the hull 10. The vertical rudder can be rotated by a vertical rudder drive motor. The vertical rudder drive motor rotates and drives the vertical rudder so that the angle corresponds to the vertical rudder control signal. The hull 10 can be pitched down (pitch down) or up (pitch up) by tilting the horizontal rudder up or down with respect to the hull 10. The horizontal rudder can be driven by a horizontal rudder drive motor. The horizontal rudder drive motor rotates and drives the horizontal rudder so that the angle corresponds to the horizontal rudder control signal. Note that a configuration may be adopted in which separate propulsion means 12 are provided on the left and right, and the hull 10 can be turned left or right by adjusting the balance of thrust of the left and right propulsion means 12 without relying on the vertical rudder.

[0058] The inspection means 14 is configured to include components for inspecting the target of the underwater vehicle 100. The inspection means 14 is configured to include a sensor for inspecting the target. For example, if the target is a submarine cable, the inspection means 14 may include an ultrasonic sensor for detecting breakage in the cable. However, the inspection means 14 is not limited to this and may have any configuration for inspecting the target of the underwater vehicle 100. Information regarding the inspection results obtained by the inspection means 14 is sent to the communication means 26.

[0059] Also, instead of or in addition to the inspection means 14, a monitoring means for monitoring the target and a repair means for repairing the target may be provided.

[0060] The imaging means 16 is configured to include components for capturing images of the outside of the hull 10. The imaging means 16 may be, for example, a camera for capturing still images, a video for capturing moving images, etc. Information (imaging data) relating to the images and moving images obtained by the imaging means 16 is sent to the communication means 26.

[0061] 3, a plurality of imaging means 16 may be provided so that the relative position between the hull 10 and the target object can be acquired based on stereoscopic vision. The relative position information can be used to correct errors in self-position estimation, which will be described later.

[0062] Furthermore, although the imaging means 16 is used in this embodiment, any detection means can be used as long as it can detect the hull 10 of the underwater vehicle 100 and a target in the base ship 300 and detect information that can confirm the relative position of the hull 10 and the target as detection data. For example, sonar can be used that can confirm the relative position of the hull 10 and the target by sending out sound waves from the hull 10 and detecting the reflection of the sound waves from the target or the bottom of the water.

[0063] The self-position estimation means 18 includes components for estimating the current position of the boat body 10 in water as its own position. The self-position estimation means 18 can be realized by, for example, a programmable microcomputer. The self-position estimation means 18 can access the memory means 22 and the position setting means 24.

[0064] The storage means 22 stores data used by the self-position estimation means 18 and information on the estimated self-position of the hull 10 in water estimated by the self-position estimation means 18. The position setting means 24 sets and stores waypoints (submerged points) indicating the initial position and route of the hull 10 when it travels underwater. The waypoints are information that sequentially represents the underwater route that is the target for the hull 10 to travel, using discrete coordinate points. The initial position and waypoints can be represented, for example, by a combination of latitude, longitude, and depth from the water surface. Also, height from the water bottom may be used instead of depth. The initial position and waypoints of the hull 10 can be set in the position setting means 24 by the base ship 300. For example, the initial position of the hull 10 can be set by inputting the GPS measurement position of the hull 10 at the base ship 300. Input to the position setting means 24 may be made using an input means constituting part of the position setting means 24 provided on the hull 10, or an input means may be provided on the base ship 300 side and connected to the position setting means 24 for input.

[0065] The self-position estimation means 18 functions as an inertial navigation system. The self-position estimation means 18 accumulates the second-order time integral of the acceleration of the hull 10 obtained by an acceleration sensor provided on the hull 10 and the first-order time integral of the speed of the hull 10 obtained by a Doppler speedometer, and estimates the current self-position of the hull 10 by adding the accumulated value to the initial position of the hull 10 stored in the position setting means 24. The depth of the hull 10 may also be estimated using a depth meter. The estimated value of the current self-position estimated by the self-position estimation means 18 is stored in the storage means 22 as estimated self-position information.

[0066] The sailing control of the hull 10 is performed based on the estimated self-position information estimated by the self-position estimation means 18. Waypoints preset in the position setting means 24 are read out in order, and the sailing means 12 is controlled so as to reduce the difference between the waypoint and the self-position of the hull 10 estimated by the self-position estimation means 18.

[0067] The navigation means 12 may be controlled based on a hull motion model. The hull motion model is also called AUV dynamics and is composed of equations of motion that represent the motion performance of the hull 10 in water. Specifically, the main propulsion drive motor, vertical rudder, horizontal rudder, etc. may be controlled based on the response characteristics of the main propulsion drive motor, vertical rudder, horizontal rudder, etc. in the navigation means 12 and the movement characteristics of the hull 10.

[0068] It should be noted that there is a possibility of a position error of about several meters being included when the GPS measured position is used as the initial position of the hull 10. Furthermore, when the self-position estimation means 18 estimates the self-position of the hull 10, a position error of about several meters is accumulated.

[0069] The error correction means 20 is configured to include components that correct errors in the estimated self-position information of the hull 10 estimated by the self-position estimation means 18. The error correction means 20 can be realized, for example, by a programmable microcomputer. The microcomputer may be common to the self-position estimation means 18. The error correction means 20 is capable of accessing the memory means 22.

[0070] The error correction means 20 performs a process of correcting and eliminating the position error (positional error) caused by an error in the estimation of the self-position of the hull 10 by the self-position estimation means 18 in accordance with the error correction information transmitted from the base ship 300 based on the captured image obtained by the imaging means 16. In other words, when the error correction information is received from the base ship 300, the error correction means 20 corrects the position error of the self-position of the hull 10 by the amount of error indicated by the error correction information. As a result, the navigation means 12 is controlled in accordance with the corrected estimated self-position information, and the position error based on the setting of the initial position of the hull 10 and the position error in the estimation of the self-position by the self-position estimation means 18 can be compensated for.

[0071] When the error correction means 20 corrects the estimated self-location information based on the error correction information, the correction amount may be continuously applied in the subsequent self-location estimation process in the self-location estimation means 18. In this way, once the estimated self-location information is corrected based on the error correction information to eliminate the error, the correction resulting from the elimination is applied as is in the subsequent estimation of the self-location, thereby improving the accuracy of the self-location estimation means of the underwater vehicle and enabling the self-location to be estimated more correctly.

[0072] The communication means 26 is configured to include components for communicating information between the underwater vehicle 100 and an external device. In this embodiment, the communication means 26 is used as a means for communicating with the relay buoy 200. Examples of communication methods between the underwater vessel 10 and the relay buoy 200 include underwater wired communication via a signal cable 28 and underwater wireless communication using acoustic signals.

[0073] In this embodiment, the underwater vehicle 100 transmits underwater captured images captured by the imaging means 16 to the base ship 300 via the relay buoy 200. Furthermore, the underwater vehicle 100 receives error correction information generated based on the captured images from the base ship 300 and controls the movement of the vessel 10 in accordance with the error correction information. Therefore, it is desirable for communication between the underwater vehicle 100 and the relay buoy 200 to be high speed, and it is preferable to use underwater wired communication using electric signals via the signal cable 28 rather than underwater wireless communication using acoustic signals. However, under conditions such as a slow speed of the vessel 10, underwater wireless communication using acoustic signals may be applied when sufficient communication time can be secured.

[0074] <Configuration of relay buoy> The relay buoy 200 according to the embodiment of the present invention includes a buoy body 30 and a communication means 32, as shown in the conceptual configuration diagram of FIG.

[0075] The buoy body 30 is a structure that constitutes the space of the relay buoy 200. The buoy body 30 is made of metal, reinforced plastic, or the like, and also plays a role in mechanically supporting the components of the relay buoy 200. The buoy body 30 also has a function of generating buoyancy to float the relay buoy 200 on the water surface.

[0076] The communication means 32 is configured to include components for communicating information between the relay buoy 200 and an external device. In this embodiment, the communication means 32 is used as a communication means for communicating between the underwater vehicle 100 and the base ship 300.

[0077] Methods of communication between the boat 10 traveling underwater and the relay buoy 200 floating on the water surface include underwater wired communication via the signal cable 28 and underwater wireless communication using acoustic signals. As described above, in this embodiment, it is preferable to use underwater wired communication using electrical signals via the signal cable 28. Wired communication can increase the speed and capacity of underwater communication.

[0078] The communication method between the base ship 300 and the relay buoy 200 includes wireless communication using a communication method such as radio waves. Specifically, for example, wireless communication includes WiFi communication, UHF communication, VHF communication, optical communication, satellite communication, and other wireless communication. It is preferable to apply wireless communication in order to prevent the movement range of the underwater vehicle 100 from being restricted as much as possible. Wireless communication prevents the communication range in the air from being limited, and increases the degree of freedom of the underwater vehicle 100. In other words, the underwater vehicle 100 can freely navigate and enables efficient monitoring over a wide area. However, wired communication using a signal cable may be applied when conditions such as a limited movement range are met.

[0079] It is preferable that the relay buoy 200 is configured to move in accordance with the movement of the underwater vehicle 100. In the case where the relay buoy 200 and the underwater vehicle 100 are wired connected by the signal cable 28, when the underwater vehicle 100 moves, the relay buoy 200 is pulled by the signal cable 28, so that the relay buoy 200 can be linked to the underwater vehicle 100. In the case where the relay buoy 200 and the underwater vehicle 100 are connected by wireless communication, it is preferable that the relay buoy 200 is configured to self-propel along with the underwater vehicle 100 when the underwater vehicle 100 moves.

[0080] <Base ship configuration> The base ship 300 in the embodiment of the present invention is a ship that serves as a mother ship for the underwater vehicle 100. As shown in the conceptual configuration diagram of Figure 5, the base ship 300 is configured to include a vessel hull 40, a positioning means 42, a position setting means 44, an image display means 46, a linking means 50, an operation means 48, and a communication means 52.

[0081] The hull 40 is a structure that constitutes the space of the base ship 300. The hull 40 is made of metal, reinforced plastic, etc., and also plays a role in mechanically supporting the components of the base ship 300. The hull 40 may also be provided with a navigation means for moving the base ship 300. If a base station located on land is used instead of the base ship 300, there is no need to provide the hull 40. If an aircraft flying in the air is used instead of the base ship 300, the hull 40 may be used instead of the aircraft body.

[0082] The positioning means 42 is configured to include a device for acquiring the current position of the base ship 300. The positioning means 42 may be, for example, a positioning means such as a Global Positioning System (GPS). However, the positioning means 42 is not limited to this, and may be configured to be capable of measuring the position of the base ship 300 according to the distance and direction from a reference point located on land.

[0083] The position setting means 44 is a means for setting the positioning information by the positioning means 42 in the underwater vehicle 100. The position setting means 44 sets the positioning information of the base ship 300 obtained by the positioning means 42 in the position setting means 24 of the underwater vehicle 100 as initial position information. That is, when the underwater vehicle 100 is mounted on the base ship 300, the positioning information by the positioning means 42 is set in the position setting means 24 as the initial position of the underwater vehicle 100. The position setting means 44 is also used to set a waypoint in the position setting means 24 of the underwater vehicle 100.

[0084] The image display means 46, the operation means 48 and the linking means 50 constitute a monitoring means 302 in the base ship 300. The monitoring means 302 is used to generate error correction information for correcting the position of the underwater vehicle 100 relative to a target.

[0085] The image display means 46 includes a device for displaying an image captured by the imaging means 16 of the underwater vehicle 100. The image display means 46 may include, for example, a display. As illustrated in Fig. 6, the image display means 46 displays an underwater image captured by the imaging means 16 of the underwater vehicle 100 based on image information acquired from the underwater vehicle 100 via a communication means 52, which will be described later. By viewing the image displayed on the image display means 46, passengers on the base ship 300 can confirm the position of the underwater vehicle 100 relative to the target.

[0086] 6 shows an actual situation of the underwater vehicle 100 and the target 400 on the left side, and an example of a captured image displayed on the image display means 46 in that situation on the right side. Fig. 6(a) shows a situation in which the target 400 is slightly included on the left side within the imaging range (camera field of view) 102 of the imaging means 16 of the underwater vehicle 100. In this case, a target area 402, which is an image of the target 400, is displayed in the left corner of the captured image displayed on the image display means 46.

[0087] The operation means 48 is a means for performing an operation to correct the position of the underwater vehicle 100. The operation means 48 can be configured to include, for example, a pointing device such as a joystick or a mouse. The manager on board the base ship 300 checks the image displayed on the image display means 46 and then operates the operation means 48, whereby error correction information for moving the underwater vehicle 100 is generated in the linkage means 50.

[0088] The linking means 50 is a means for linking the image displayed on the image display means 46 with error correction information for the underwater vehicle 100 operated by the operation means 48. The linking means 50 can be realized, for example, by a programmable microcomputer. The microcomputer may be a common device for controlling the image display means 46 and the operation means 48. The linking means 50 generates error correction information for correcting estimated self-position information estimated by the self-position estimation means 18 of the underwater vehicle 100 in accordance with the amount of operation of the operation means 48. The linking means 50 generates error correction information such that the amount of correction of the estimated self-position information increases as the amount of operation of the operation means 48 increases.

[0089] For example, when the operation means 48 is a pointing device such as a joystick or a mouse, error correction information is generated based on the amount and direction of the operation to correct the estimated self-position information so that the underwater vehicle 100 is moved in the relevant direction by a distance corresponding to the amount of operation. Also, when the operation means 48 is a touch panel integrated with the image display means 46, error correction information is generated based on the amount and direction of the operation to move (swipe) the target area 402 displayed on the image display means 46 within the screen to correct the estimated self-position information so that the underwater vehicle 100 is moved in the opposite direction (the direction in which the target 400 moves in the direction in which it is moved within the captured image) by a distance corresponding to the amount of operation. The relationship of the correction amount of the movement distance of the underwater vehicle 100 to the amount of operation may be set in advance.

[0090] This allows the underwater vehicle to be moved with high accuracy relative to the target displayed on the screen and face the correct position. Also, the underwater vehicle can be moved with high accuracy in real time relative to the target displayed on the screen.

[0091] If the target 400 is not shown in the captured image, error correction information may be generated based only on the operation of the operating means 48, regardless of the image displayed on the image display means 46. For example, the error correction information may not be generated by the administrator not operating the operating means 48, or error correction information may be generated such that the correction amount of the estimated self-position information is substantially zero. Also, if the target 400 is not shown in the captured image displayed on the image display means 46 when the hull 10 has reached a waypoint on the target 400, the administrator may be allowed to operate the operating means 48 to correct the position of the hull 10.

[0092] The communication means 52 includes a device for receiving information transmitted from the underwater vehicle 100 to the base ship 300 and transmitting information from the base ship 300 to the underwater vehicle 100. In this embodiment, communication between the underwater vehicle 100 and the base ship 300 is performed via the relay buoy 200, so the base ship 300 is used as a wireless communication means for communicating with the relay buoy 200. When communication with the relay buoy 200 is performed wirelessly, the communication means 52 includes a device for wireless communication using a communication method such as radio waves. Specifically, it may include a wireless communication device such as WiFi communication, UHF communication, satellite communication, etc.

[0093] In this embodiment, the error correction information is generated by the linking means 50 based on the operation of the operation means 48 by the administrator, but the error correction information may also be generated automatically by the linking means 50 (or the operation means 48) without being dependent on the operation of the administrator.

[0094] For example, a captured image transmitted from the underwater vehicle 100 may be image-processed to identify a target area 402 in which the target 400 is displayed in the image from the characteristics (shape, color, etc.) of the target 400, and error correction information may be generated for moving the underwater vehicle 100 so that the target area 402 is located at the center of the captured image. In other words, based on the direction and magnitude of the deviation of the current position of the target area 402 from the center position of the image in the image, error correction information may be generated to correct estimated self-position information so as to move the underwater vehicle 100 in that direction by a distance corresponding to the amount of deviation.

[0095] At this time, the distance between the hull 10 of the underwater vehicle 100 and the target 400 may be calculated based on the size of the target area 402 in the captured image, and the amount of correction of the estimated self-position information using the error correction information may be adjusted according to the distance. In other words, the amount of correction of the movement of the hull 10 relative to the amount of deviation of the position of the target area 402 from the center position of the image in the image may be set to be larger as the distance between the hull 10 and the target 400 increases.

[0096] If the underwater vehicle 100 is equipped with a position measurement means, the position measurement means may measure the relative distance between the hull 10 of the underwater vehicle 100 and the target 400. By transmitting the measurement value from the underwater vehicle 100 to the base ship 300 via the relay buoy 200, error correction information may be generated according to the relative distance between the hull 10 of the underwater vehicle 100 and the target 400.

[0097] In addition, the amount of positional deviation between the underwater vehicle 100 and the target 400 may be calculated from the seabed image captured by the imaging means 16 when the waypoint is reached and the depth (altitude) and attitude information of the hull 10 of the underwater vehicle 100, and error correction information may be generated based on the amount of deviation.

[0098] In addition, when the underwater vehicle 100 is provided with a plurality of imaging means 16 and can capture stereoscopic images, the relative position between the hull 10 and the target 400 may be calculated based on the stereoscopic images. Images captured by the plurality of imaging means 16 are transmitted from the underwater vehicle 100 to the base ship 300 via the relay buoy 200, and a stereoscopic image is generated based on the captured images, and the relative distance between the hull 10 of the underwater vehicle 100 and the target 400 is calculated based on the stereoscopic images. Error correction information may then be generated according to the relative distance between the hull 10 of the underwater vehicle 100 and the target 400. It is possible to control the movement of the underwater vehicle in accordance with the actually measured relative distance between the underwater vehicle and the target using stereoscopic images or the like, with a simple configuration.

[0099] 6(b), the underwater vehicle 100 can be autonomously navigated along the waypoints to approach the target, and the resulting position error can be corrected while the hull 10 of the underwater vehicle 100 is moved so that the target 400 is positioned at the center of the imaging range 102 captured by the imaging means 16. This makes it possible to appropriately inspect, monitor, repair, etc. the target 400 by the underwater vehicle 100 with improved accuracy and efficiency.

[0100] Furthermore, for example, when the underwater vehicle 100 is capable of continuously capturing images, even while the underwater vehicle 100 is sailing, the positional deviation of the underwater vehicle 100 may be calculated from the difference between the estimated self-position by the self-position estimation means 18 and the self-position estimated value by a concatenated image (mosaic image) of the captured images. In this case, error correction information for correcting the estimated self-position information in accordance with the deviation may be generated. That is, error correction information may be generated for correcting the estimated self-position information based on the direction and magnitude of the deviation so as to move the underwater vehicle 100 in the direction by a distance corresponding to the deviation.

[0101] This makes it possible to correct the movement of the hull 10 of the underwater vehicle 100 in response to a deviation in the position of the underwater vehicle 100.

[0102] In addition, when error correction information is automatically generated in the linking means 50 (or the operation means 48), there is no need to have the administrator understand the situation by displaying the captured image on the image display means 46, so it is possible not to display the actual image on the image display means 46.

[0103] As described above, according to this embodiment, it is possible to reduce errors in estimating the self-position during autonomous traveling of the underwater vehicle 100. This makes it possible to improve work efficiency by correcting errors in estimating the self-position when the underwater vehicle is used for inspection, monitoring, repair, etc. of underwater targets.

[0104] Here, by using wired communication between the underwater vehicle 100 and the relay buoy 200, communication can be performed at a higher speed than by using acoustic signals to transmit underwater. This allows the captured image to be transmitted to the base ship 300, and the base ship 300 can correct the position of the underwater vehicle 100 based on the captured image with a high response speed, almost in real time. By using wireless communication between the base ship 300 and the relay buoy 200, the movable range of the underwater vehicle 100 can be expanded compared to the case of using wired communication. [Industrial Applicability]

[0105] The present invention can be applied to highly accurate navigation control of an autonomous underwater vehicle, target monitoring, etc. For example, in the inspection, monitoring, repair, etc. of underwater targets by an underwater vehicle, the work efficiency can be improved by correcting the estimation error of the self-position. [Explanation of symbols]

[0106] 10 vessel body, 12 navigation means, 14 inspection means, 16 imaging means (detection means), 18 self-position estimation means, 20 error correction means, 22 memory means, 24 position setting means, 26 communication means, 28 signal cable, 30 buoy body, 32 communication means, 40 vessel body, 42 positioning means, 44 position setting means, 46 image display means, 48 ​​operation means, 50 linking means, 52 communication means, 100 underwater vessel, 102 imaging range (camera field of view), 200 relay buoy (buoy means), 300 base ship, 302 monitoring means, 400 target, 402 target area.

Claims

1. A method for correcting an error in estimating a self-position of an underwater vehicle, comprising: a target position is set on the underwater vehicle equipped with a detection means for detecting a target and a self-position estimation means, the underwater vehicle is caused to navigate and approach the target; acquiring detection data of the target detected by the detection means; transmitting the detection data to a monitoring means by wireless communication; A method for correcting self-position estimation errors for an underwater vehicle, characterized in that the monitoring means monitors the positional error between the target and the underwater vehicle based on the detection data, and, if there is a positional error, an operation means performs processing to eliminate the positional error caused by an error in the estimation of the self-position by the self-position estimation means.

2. A method for correcting a self-position estimation error of an underwater vehicle according to claim 1, comprising: the detection means is an imaging means that captures an image and obtains imaging data as the detection data; A method for correcting self-position estimation errors of an underwater vehicle, characterized in that an image based on the imaging data displayed on an image display means provided in the monitoring means is monitored, and when there is a positional error between the target and the underwater vehicle, the positional error is eliminated while monitoring the image by operating the operating means.

3. A method for correcting an error in estimating a position of an underwater vehicle according to claim 2, comprising the steps of: A method for correcting self-position estimation error of an underwater vehicle, characterized in that when the target is within the screen of the image display means, the positional error is eliminated while monitoring the screen by operating the operation means.

4. A method for correcting a self-position estimation error of an underwater vehicle according to claim 3, comprising the steps of: A method for correcting an error in self-position estimation for an underwater vehicle, comprising: recognizing a distance and a direction between said target object and said underwater vehicle in real time; and eliminating said positional error by operating said operating means.

5. A method for correcting an error in estimating a position of an underwater vehicle according to any one of claims 1 to 4, comprising the steps of: A method for correcting self-position estimation errors of an underwater vehicle, characterized in that the detection data is transmitted to a buoy means facing the water surface via underwater wired communication, and the detection data is further transmitted from the buoy means to the monitoring means using radio waves as the wireless communication.

6. A method for correcting an error in estimating a position of an underwater vehicle according to any one of claims 1 to 5, comprising the steps of: A method for correcting self-position estimation errors of an underwater vehicle, characterized in that the underwater vehicle is equipped with a position measurement means, relative position information with respect to the target is transmitted to the monitoring means, and the position information is also utilized when eliminating the position error by the operation means.

7. A method for correcting a self-position estimation error of an underwater vehicle according to claim 6, comprising the steps of: A method for correcting self-position estimation error of an underwater vehicle, comprising providing a plurality of the detection means, each of which also serves as the position measurement means, and acquiring the position information simultaneously with the detection.

8. A method for correcting an error in estimating a position of an underwater vehicle according to any one of claims 1 to 7, comprising the steps of: A method for correcting self-position estimation error for an underwater vehicle, comprising setting a waypoint for the underwater vehicle and using the self-position estimation means to navigate the underwater vehicle toward the waypoint.

9. A method for correcting a self-position estimation error of an underwater vehicle according to claim 8, comprising the steps of: A method for correcting self-position estimation errors for an underwater vehicle, characterized in that the position of the underwater vehicle that is estimated to have reached the waypoint by the monitoring means is determined, and the position of the underwater vehicle is corrected based on instructions from the monitoring means in accordance with the results of the positioning.

10. A method for correcting an error in estimating a position of an underwater vehicle according to any one of claims 1 to 9, comprising: A method for correcting an error in self-position estimation of an underwater vehicle, comprising the steps of: utilizing a result of elimination of the position error by the operation means for correcting the self-position estimation means.

11. A self-position estimation error correction system for an underwater vehicle, comprising: The underwater vehicle is equipped with a detection means for detecting a target and a self-position estimation means; a position setting means for setting a position of a target on the underwater vehicle; a monitoring means having an operation means for operating the underwater vehicle; a wireless communication means for transmitting detection data of the target detected by the detection means to the monitoring means; A self-position estimation error correction system for an underwater vehicle, characterized in that it is equipped with a linking means that, when there is a positional error between the target and the underwater vehicle, enables the positional error of the underwater vehicle caused by an error in the estimation of its own position by the self-position estimation means to be eliminated by operating the operating means while monitoring based on the detection data.

12. The self-position estimation error correction system for an underwater vehicle according to claim 11, the detection means is an imaging means that captures an image and obtains imaging data as the detection data; The linking means monitors images based on the imaging data displayed on an image display means provided in the monitoring means, and when there is a positional error between the target and the underwater vehicle, enables the positional error to be eliminated while monitoring the images using the operation means.

13. A self-position estimation error correction system for an underwater vehicle according to claim 12, A self-position estimation error correction system for an underwater vehicle, characterized in that when the target is within the screen of the image display means, it is possible to eliminate the positional error while monitoring the screen using the operation means.

14. A self-position estimation error correction system for an underwater vehicle according to claim 13, A self-position estimation error correction system for an underwater vehicle, characterized in that it recognizes the distance and direction between the target and the underwater vehicle in real time and enables the positional error to be eliminated by the operating means.

15. A self-position estimation error correction system for an underwater vehicle according to any one of claims 11 to 14, A self-position estimation error correction system for an underwater vehicle, further comprising a buoy means for facing the water surface and a signal cable connecting the underwater vehicle and the buoy means, wherein the detection data is transmitted to the buoy means by underwater wired communication via the signal cable, and the detection data is transmitted from the buoy means to the monitoring means using radio waves via the wireless communication means.

16. A self-position estimation error correction system for an underwater vehicle according to claim 14 or 15, A self-position estimation error correction system for an underwater vehicle, characterized in that the underwater vehicle has a position measurement means, the position measurement means transmits relative position information with respect to the target to the monitoring means, and the position information is used when the operation means eliminates the position error.

17. A self-position estimation error correction system for an underwater vehicle according to claim 16, A self-position estimation error correction system for an underwater vehicle, comprising: a plurality of detection means each serving as the position measurement means, and acquiring the position information simultaneously with the detection.

18. A self-position estimation error correction system for an underwater vehicle according to any one of claims 11 to 17, A self-position estimation error correction system for an underwater vehicle, characterized in that the underwater vehicle is provided with a memory means for storing waypoints previously set by the position setting means, and the underwater vehicle is navigated toward the target using the self-position estimation means in accordance with the stored waypoints.

19. A self-position estimation error correction system for an underwater vehicle according to claim 18, A self-position estimation error correction system for an underwater vehicle, characterized in that the monitoring means is provided with a positioning means for measuring the position of the underwater vehicle, the position of the underwater vehicle that is estimated to have reached the waypoint is measured by the positioning means, and the monitoring means issues an instruction to correct the position of the underwater vehicle in accordance with the results of the positioning.

20. A self-position estimation error correction system for an underwater vehicle according to any one of claims 11 to 19, 2. A self-position estimation error correction system for an underwater vehicle, further comprising: error correction means for utilizing a result of elimination of the position error by the operation means for correcting the self-position estimation means.

21. A self-position estimation error correction system for an underwater vehicle according to any one of claims 10 to 18, 1. A self-position estimation error correction system for an underwater vehicle, wherein the self-position estimation means has at least one of an inertial navigation system, a Doppler speedometer, and a depth meter.

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