Underwater diving system, piloting assistance device and program

Abstract

To provide an underwater navigation system capable of maintaining the state that an underwater cruising body faces an inspection object.SOLUTION: A maneuvering auxiliary computer 60 detects a reference linear image in a reference image including a distribution map of a measured result by a sonar 21 as a reference line segment, and then detects the linear image of a comparison object in a comparison object image including the distribution map as the line segment of the comparison object, calculates a difference between the reference line segment and the line segment of the comparison object, and commands the control unit 22 to correct control of a propeller 15 according to a signal of a maneuvering device 40 based on the difference.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an underwater submersible system having an underwater submersible that submerges underwater, and also to a steering assist device and a program therefor that instruct a control unit to correct control of the propulsion unit of the underwater submersible in accordance with a signal from a controller. [Background technology]

[0002] Patent Document 1 discloses an underwater exploration robot equipped with a propulsion unit, a camera, a sonar, etc. The dam wall surface is inspected using such an underwater exploration robot. Specifically, the underwater exploration robot is submerged to the dam wall surface by the propulsion unit, and while moving the underwater exploration robot along the dam wall surface by the propulsion unit, the dam wall surface is photographed by the camera to investigate the presence and size of damage, etc. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-26350 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, if the underwater exploration robot is not kept facing the dam wall, trapezoidal distortion occurs in the dam wall image captured by the camera, and the scale of the dam wall in the image varies, making it impossible to accurately inspect the damage to the dam wall. Therefore, the present invention has been made in consideration of the above circumstances, and has an object to enable an underwater submersible such as an underwater exploration robot to maintain a position facing directly toward an inspection object such as a dam wall. [Means for solving the problem]

[0005] In order to solve the above problems, an underwater submersible system includes an underwater submersible body, a controller, a propulsion device provided in the underwater submersible body for generating a propulsive force for the underwater submersible body to move forward and backward and for generating a moment for the yaw of the underwater submersible body, a control device for controlling the propulsion device in accordance with a signal from the controller, a detection device provided in the underwater submersible body for transmitting a beam that spreads left and right toward the front of the underwater submersible body and for periodically detecting the intensity of the reflected wave for each distance and direction to the object to be inspected based on the reflected wave received from the object to be inspected in front of the underwater submersible body, a distribution map generating means for generating an image including a distribution map that expresses the intensity of the reflected wave for each distance and direction in gradations each time the detection device detects the intensity of the reflected wave for each distance and direction, and a first detection means for detecting a reference linear image representing the object to be inspected as a reference line segment in a distribution map in a predetermined image generated by the means; a second detection means for detecting a comparison linear image representing the object to be inspected as a comparison line segment in the distribution map in the comparison image each time a comparison image subsequent to the predetermined image is generated by the distribution map generation means; a difference calculation means for calculating a difference between the reference line segment and the comparison line segment each time the comparison line segment is detected by the second detection means; and a piloting assistance means for instructing the control unit to correct the control of the propulsion unit in accordance with the signal of the controller based on the difference calculated by the difference calculation means each time a difference is calculated by the difference calculation means.

[0006] According to the above, the underwater submersible can be maintained facing the object to be inspected directly, and the distance from the underwater submersible to the object to be inspected can be maintained constant.

[0007] Preferably, the piloting assistance means has a first correction value calculation means for calculating a correction value for the yaw moment based on the difference calculated by the difference calculation means, and a first output means for outputting the correction value calculated by the first correction value calculation means to the control unit, and the control unit adds the correction value output by the first output means to a moment command value represented by the signal of the controller, and controls the propulsion unit to generate a moment in accordance with the sum. More preferably, the difference calculation means calculates an inclination angle of the comparison target line segment with respect to the reference line segment as the difference between the reference line segment and the comparison target line segment.

[0008] According to the above, the underwater submersible can be maintained facing directly toward the object to be inspected.

[0009] Preferably, the piloting assistance means has a second correction value calculation means for calculating a correction value for forward and backward thrust based on the difference calculated by the difference calculation means, and a second output means for outputting the correction value calculated by the second correction value calculation means to the control unit, and the control unit adds the correction value output by the second output means to the command value for the forward and backward thrust represented by the signal from the controller, and controls the propulsion unit to generate a forward and backward thrust in accordance with the sum. More preferably, the difference calculation means calculates a distance from a midpoint of the comparison target line segment to a midpoint of the reference line segment as the difference between the reference line segment and the comparison target line segment.

[0010] According to the above, the distance from the underwater submersible to the object to be inspected can be maintained constant. Effect of the Invention

[0011] According to the present invention, the underwater submersible body is maintained facing the object to be inspected directly, and the distance from the underwater submersible body to the object to be inspected is kept constant. [Brief description of the drawings]

[0012] [Figure 1]FIG. 1 is a perspective view of an underwater exploration robot. [Diagram 2] FIG. 1 is a block diagram of an underwater exploration system. [Diagram 3] FIG. 1 is an explanatory diagram of a distribution diagram of echo intensity. [Figure 4] 13 is an example of a distribution map of echo intensity displayed on a display device. [Diagram 5] 13 is an example of a distribution map of echo intensity displayed on a display device. [Figure 6] 13 is an example of a distribution map of echo intensity displayed on a display device. [Figure 7] 13 is an example of a distribution map of echo intensity displayed on a display device. [Figure 8] The figures show a state in which the underwater exploration robot faces an object to be inspected, and a state in which the underwater exploration robot is tilted left and right around a vertical axis. [Figure 9] 13 is an example of a distribution map of echo intensity displayed on a display device. [Figure 10] 4 is a flowchart of the processing of a pilot assistance computer. [Figure 11] FIG. 2 is an explanatory diagram of a reference line segment detected by a pilot assistance computer. [Figure 12] 13 is an example of a distribution map of echo intensity displayed on a display device. [Figure 13] FIG. 13 is an explanatory diagram of a comparison target line segment detected by a pilot assistance computer. [Figure 14] FIG. 1 is an explanatory diagram of the tilt angle and distance calculated by the pilot assistance computer. [Figure 15] 1 is an explanatory diagram of the operation of an underwater exploration robot. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. However, the embodiment described below is subject to various technically preferable limitations for carrying out the present invention, but the scope of the present invention is not limited to the following embodiment and illustrated examples.

[0014] <Outline of the Underwater Exploration System (Underwater Submersible System)> FIG. 1 is a perspective view of an underwater exploration robot 10 as an underwater submersible. FIG. 2 is a block diagram of an underwater exploration system equipped with the underwater exploration robot 10. The underwater exploration system is also an underwater submersible system. In FIG. 1, arrows in the forward / backward direction, left / right direction, and up / down direction are shown, and the forward / backward direction is defined by the direction of the propulsive force generated by a forward / backward thruster 15a described later mounted on the underwater exploration robot 10, the left / right direction is defined by the direction of the propulsive force generated by a left / right thruster 15b described later mounted on the underwater exploration robot 10, and the up / down direction is defined by the direction of the propulsive force generated by a up / down thruster 15c described later mounted on the underwater exploration robot 10.

[0015] The underwater exploration system includes an underwater exploration robot 10, a controller 40, and two computer systems. One computer system has a monitoring computer 50, an input device 51, a display device 52, and a storage device 53. The monitoring computer 50 has a CPU, RAM, ROM, GPU, a bus, various interfaces, etc. The input device 51 is made up of a keyboard and a pointing device. The display device 52 is a liquid crystal display device or an organic EL display device. The storage device 53 is a writable and readable storage device made up of a semiconductor memory, a solid state drive, a hard disk drive, etc.

[0016] The other computer system has a pilot assistance computer 60, an input device 61, a display device 62, and a storage device 63. The pilot assistance computer 60 has a CPU, RAM, ROM, GPU, a bus, various interfaces, etc. The input device 61 is made up of a keyboard and a pointing device. The display device 62 is a liquid crystal display device or an organic EL display device. The storage device 63 is a writable and readable storage device made up of a semiconductor memory, a solid state drive, a hard disk drive, etc.

[0017] The underwater exploration robot 10 is connected via cables to a controller 40 and computers 50 and 60. An operator operates the underwater exploration robot 10 on the water surface using the controller 40, and uses the underwater exploration robot 10 to inspect an inspection target such as a dam wall surface.

[0018] The controlled underwater exploration robot 10 photographs the object to be inspected while diving underwater. The images photographed by the underwater exploration robot 10 are transferred to the monitoring computer 50, and the images are displayed on the display device 52 by the monitoring computer 50. This allows an operator to visually inspect the object to be inspected.

[0019] In addition, the underwater exploration robot 10 photographs itself while submerged, and the image of the underwater exploration robot 10 is transferred to the monitoring computer 50, and the image is displayed on the display device 52 by the monitoring computer 50. This allows workers on the surface to visually check the status of the underwater exploration robot 10.

[0020] Furthermore, a signal indicating the operating state of the underwater exploration robot 10 is transferred to the monitoring computer 50, and the operating state of the underwater exploration robot 10 is displayed on the display device 52 by the monitoring computer 50. This allows the operator to recognize the operating state of the underwater exploration robot 10.

[0021] Due to poor visibility caused by turbidity of water, the image captured by the underwater exploration robot 10 may not be clear. Even in such a case, the underwater exploration robot 10 has a sonic exploration function so that the inspection object can be searched for. That is, the underwater exploration robot 10 measures the echo intensity for each distance and direction by transmitting a sonic beam and receiving an echo. The sonic wave includes not only sound waves in the audible range but also ultrasonic waves. The echo refers to a reflected sound wave that travels to the underwater exploration robot 10 by reflecting the sonic beam off the inspection object and obstacles. The distance refers to the distance forward from the underwater exploration robot 10, and the direction refers to the angle from the front to the left and right. The detection results of the echo intensity for each distance and direction are transferred to the underwater exploration robot 10, and a distribution map of the polar coordinate system showing the distribution of the echo intensity for each distance and direction is displayed on the display device 52 by the monitoring computer 50. By looking at the distribution map, the worker can confirm whether the inspection object or obstacle is present near the underwater exploration robot 10. Furthermore, the operator can visually confirm the distance and direction in the distribution map where the echo intensity is high, and can visually confirm that an inspection target or obstacle exists at such a distance and direction.

[0022] A video signal of the distribution map of echo intensity is transferred from the monitoring computer 50 to the piloting assistance computer 60. The piloting assistance computer 60 performs a capturing process on the video signal to capture an image of the distribution map. The piloting assistance computer 60 controls the underwater exploration robot 10 based on the image of the distribution map so as to assist the pilot 40 in piloting the underwater exploration robot 10. This keeps the distance from the inspection object to the underwater exploration robot 10 constant, and keeps the underwater exploration robot 10 facing the inspection object directly.

[0023] <Underwater exploration robot (underwater submersible)> The underwater exploration robot 10 will now be described in detail. The underwater exploration robot 10 has a frame 11, a pressure-resistant container 12, a camera 13, a fisheye lens camera 14, a propulsion unit 15, an attitude control device 16, a cleaning unit 17, a headlight 18, a linear light projector 19, a sonar 21 and a control unit 22.

[0024] The frame 11 is made by assembling a number of pipes into a rectangular parallelepiped shape. The pressure vessel 12 is attached to the frame 11. The pressure vessel 12 accommodates a control unit 22 and a battery.

[0025] The camera 13 is attached to the front of the frame 11. Here, the direction in which the camera 13 faces is defined as the front, and the opposite direction is defined as the rear. The left and right directions are determined by looking from the back to the front.

[0026] The camera 13 includes a box lens 13a and an electronic camera 13b. The box glasses 13a are provided in a box shape so as to have a sealed space inside. The box glasses 13a have a transparent surface so that the outside can be seen from the inside. The box glasses 13a are attached to the front of the frame 11 with the transparent surface facing forward.

[0027] The electronic camera 13b is attached inside the box glasses 13a facing forward. The electronic camera 13b photographs the foreground and outputs a signal of the photographed image of the foreground to the control unit 22. The electronic camera 13b has a zoom function, and the angle of view of the electronic camera 13b can be adjusted electrically. The electronic camera 13b also has a tilt-pan function for tilting up, down, left, and right, and the elevation / depression angle and azimuth angle of the optical axis of the electronic camera 13b can be adjusted electrically.

[0028] Clear water is filled in the box glasses 13a, and the electronic camera 13b is immersed in the clear water, so that the foreground can be photographed clearly by the electronic camera 13b.

[0029] The fisheye lens camera 14 is attached to a support column at the rear of the frame 11. The fisheye lens camera 14 photographs the underwater exploration robot 10 from above the underwater exploration robot 10 and outputs a signal of the photographed image to the control unit 22.

[0030] The propulsion unit 15 is attached to the frame 11. The propulsion unit 15 propels the underwater exploration robot 10 in the forward / backward, left / right, and up / down directions, and rotates it around the up / down axis. The propulsion unit 15 can also drift the underwater exploration robot 10. Drifting means simultaneously propelling forward, backward, up, down, left, or right and rotating around the up / down axis. Hereinafter, the rotation around the up / down axis is referred to as yaw, the rotation around the front / back axis is referred to as roll, and the rotation around the left / right axis is referred to as pitch. In addition, the attitude of the underwater exploration robot 10 when the up / down axis is vertical and the front / back axis and the left / right axis are horizontal is referred to as the basic attitude. The rotation angle around the front / back axis from the basic attitude is referred to as roll angle, and the rotation angle around the left / right axis from the basic attitude is referred to as pitch angle. The propulsion machine 15 is controlled by the control unit 22 to adjust the forward / backward, left / right, up / down propulsive forces and the yaw moment.

[0031] The propulsion unit 15 has two forward and rear thrusters 15a, two left and right thrusters 15b, and an up and down thruster 15c. Here, in Fig. 1, the forward and rear thruster 15a provided on the left rear part of the frame 11 is illustrated, and the forward and rear thruster 15a provided on the right rear part of the frame 11 is not illustrated because it is hidden behind the components of the underwater exploration robot 10. Similarly, one left and right thruster 15b is illustrated, and the other left and right thruster 15b is not illustrated because it is hidden behind the components of the underwater exploration robot 10.

[0032] The front and rear thrusters 15a each generate a propulsive force in the front and rear direction by themselves. Since the propulsive force of the front and rear thrusters 15a can be adjusted individually, the front and rear thrusters 15a generate a yaw moment by balancing the propulsive forces of the two thrusters. Therefore, the front and rear thrusters 15a propel the underwater exploration robot 10 in the front and rear directions and also yaw the underwater exploration robot 10. The left and right thrusters 15b propel the underwater exploration robot 10 in the left and right directions. The vertical thruster 15c propels the underwater exploration robot 10 in the vertical direction.

[0033] The attitude control device 16 has a housing, a flywheel, a three-axis gimbal, a spindle motor, a gyro sensor, and the like. The control unit 22 controls the three-axis gimbal and the spindle motor of the attitude control device 16 based on the angular velocity detected by the gyro sensor of the attitude control device 16. As a result, the attitude control device 16 controls the roll, pitch, and yaw moments by the gyro effect of the flywheel so as to cancel the moment acting on the underwater exploration robot 10 due to an external force such as a water flow. As a result, the attitude of the underwater exploration robot 10 is stably maintained in the basic attitude. In addition, the attitude control device 16 pitches the underwater exploration robot 10 by controlling the pitch moment, thereby causing the underwater exploration robot 10 to have a forward tilting attitude or a backward tilting attitude. The attitude control device 16 causes the underwater exploration robot 10 to have a left downward attitude or a right downward attitude by controlling the roll moment.

[0034] The buoyant materials 20 are attached to the frame 11. The buoyant materials 20 provide buoyancy to the underwater exploration robot 10. The buoyancy of the buoyant materials 20 is set to balance the sinking force due to the weight of the underwater exploration robot 10. The buoyancies of the buoyant materials 20 are also balanced so that the basic posture of the underwater exploration robot 10 is maintained.

[0035] The cleaning unit 17 is attached to the rear of the frame 11. The cleaning unit 17 is, for example, a rotary electric scraper, and removes deposits from the surface of the inspection object that comes into contact with the cleaning unit 17. The cleaning unit 17 is driven by the control unit 22.

[0036] The headlights 18 are attached to the front of the frame 11 in a pair on the left and right, facing forward. The headlights 18 emit illumination light forward to illuminate the shooting range of the electronic camera 13b. The headlights 18 are controlled by the control unit 22 to be turned on, off, and dimmed.

[0037] The linear bright area projectors 19 are attached to the front of the frame 11 in a pair on the left and right, facing forward. The linear bright area projectors 19 irradiate parallel beams that are diffused in the vertical direction and focused in the horizontal direction, respectively, into the forward shooting range. When the parallel beams emitted from the linear bright area projectors 19 are incident on an object to be inspected in front, parallel linear bright areas extending in the vertical direction are formed on the object to be inspected. The interval between the linear bright areas is set to a predetermined value, and distance or length can be estimated using the linear bright areas as visual targets.

[0038] The linear bright area projector 19 is controlled by the control unit 22 so that the linear bright area projector 19 is turned on and off.

[0039] The sonar 21 is attached to the front of the frame 11 in a forward facing state. The sonar 21 is a detection unit that detects the distance and direction to an object to be inspected in front, and is a multi-beam sonar having multiple transmitters, multiple receivers, and a signal processing circuit. When each transmitter of the sonar 21 is driven by the control unit 22, the sonar 21 transmits a sound beam that spreads in the left-right direction and is narrowed in the up-down direction toward the front by the multiple transmitters. The direction of the swath width of the sound beam is the left-right direction, and the direction of the center line of the sound beam that spreads in a fan shape from the sonar 21 to the left and right is the front-rear direction. The direction refers to the angle from the center line of the sound beam to the left and right. The sonar 21 receives echoes from the transmitted sound beams from the front by receivers and detects the intensity of the echoes. When the echo intensity detected by each receiver of the sonar 21 is signal-processed by the signal processing circuit, the echo intensity is calculated for each distance and direction by the signal processing circuit. A signal of the echo intensity for each distance and direction is output from the signal processing circuit of the sonar 21 to the control unit 22. The sonar 21 periodically detects the echo intensity for each distance and direction.

[0040] <Control unit, monitoring computer and controller> The control unit 22 comprehensively controls the electronic camera 13b, the fisheye lens camera 14, the propulsion unit 15, the attitude control device 16, the cleaning unit 17, the headlight 18, the linear bright area projector 19 and the sonar 21.

[0041] The control unit 22 controls the electronic camera 13b, whereby the electronic camera 13b captures an image of the foreground, and a signal of the image is transferred to the control unit 22. The control unit 22 transfers the signal of the image captured by the electronic camera 13b to the monitoring computer 50. The monitoring computer 50 performs sharpening processing on the image captured by the electronic camera 13b, and outputs the signal of the image after sharpening processing to the display device 52. Therefore, the image captured by the electronic camera 13b is displayed on the display device 52. Similarly, the control unit 22 controls the fisheye lens camera 14, whereby the image captured by the fisheye lens camera 14 is displayed on the display device 52.

[0042] The monitoring computer 50 converts the signal of the image after sharpening processing captured by the electronic camera 13b into a predetermined moving image format, and records the moving image in that format in the storage device 53. The monitoring computer 50 also performs a capturing process of the signal of the image after sharpening processing captured by the electronic camera 13b at a predetermined timing or at a predetermined cycle, and records a still image in the storage device 53.

[0043] The control unit 22 calculates the roll angle, pitch angle, and yaw angle of the underwater exploration robot 10 from the angular velocity detected by the gyro sensor of the attitude control device 16, and controls the attitude control device 16 based on the roll angle, pitch angle, and yaw angle. As a result, the attitude control device 16 adjusts the roll, pitch, and yaw moments to stabilize the attitude of the underwater exploration robot 10. The control unit 22 also transfers the calculated roll angle and pitch angle to the monitoring computer 50, and the monitoring computer 50 displays the roll angle and pitch angle as numerical values ​​on the display device 52. The control unit 22 has a built-in azimuth sensor, and the azimuth angle detected by the azimuth sensor is transferred to the monitoring computer 50 by the control unit 22. The monitoring computer 50 displays the azimuth angle on the display device 52.

[0044] The controller 40 is provided with switches for operating the electronic camera 13b. When an operator operates a switch on the controller 40, an operation signal is sent from the controller 40 to the electronic camera 13b via the control unit 22. This allows the electronic camera 13b to be turned on and off and to be controlled to zoom, tilt, and pan. Similarly, the operator can operate the controller 40 to turn on and off the fisheye lens camera 14, the cleaning unit 17, the headlight 18, the linear bright area projector 19, and the sonar 21.

[0045] The control unit 22 detects whether the headlights 18 and the linear bright area projector 19 are on or off, and transfers the detection results to the monitoring computer 50. The monitoring computer 50 causes the display device 52 to display the detection results of whether the headlights 18 and the linear bright area projector 19 are on or off. The control unit 22 detects the operating state of the cleaning unit 17, for example the rotation direction of the scraper, and transfers the detection result to the monitoring computer 50. The monitoring computer 50 causes the display device 52 to display the detection result of the operating state of the cleaning unit 17.

[0046] The controller 40 is provided with an operating lever for forward and backward travel. When an operator operates this operating lever, a command value for thrust force according to the displacement of this operating lever is sent as a signal from the controller 40 to the control unit 22, and the control unit 22 controls the thrust force of the forward and backward thrusters 15a of the propulsion unit 15 to the command value. This makes it possible to adjust the acceleration and speed of forward and backward travel of the underwater exploration robot 10. Similarly, the thrust force of the left and right thrusters 15b is controlled according to the displacement of the operating lever for left and right travel, and the thrust force of the up and down thrusters 15c is controlled according to the displacement of the operating lever for up and down travel.

[0047] The controller 40 is provided with an operating lever for turning left and right. When an operator operates this operating lever, a command value for the yaw moment according to the displacement of this operating lever is sent as a signal from the controller 40 to the control unit 22, and the control unit 22 controls the moment of the front and rear thrusters 15a of the propulsion unit 15 to the command value. This makes it possible to adjust the yaw angular acceleration and angular velocity of the underwater exploration robot 10.

[0048] The controller 40 is also provided with an operating lever for tilting forward and tilting backward. When an operator operates this operating lever, a signal is sent from the controller 40 to the control unit 22, and the control unit 22 controls the attitude control device 16. This makes it possible to adjust the pitch angle of the underwater exploration robot 10. Similarly, the controller is provided with operating levers for lowering left and lowering right, and the control unit 22 controls the attitude control device 16 in accordance with the signal from this operating lever, making it possible to adjust the roll angle of the underwater exploration robot 10.

[0049] The functions of the controller 40 may be realized in software by the monitoring computer 50 and the input device 51. Therefore, an operator can remotely control the electronic camera 13b, the fisheye lens camera 14, the propulsion unit 15, the cleaning unit 17, the headlight 18, and the linear bright area projector 19 by operating the input device 51. In this case, the combination of the monitoring computer 50 and the input device 51 corresponds to the controller.

[0050] The control unit 22 controls the sonar 21, which causes the sonar 21 to transmit a sound beam and detect echo intensities for each distance and direction based on the received echoes. The sonar 21 outputs the echo intensities for each distance and direction to the control unit 22, which then transfers the echo intensities for each distance and direction to the monitoring computer 50. The monitoring computer 50 generates a distribution map in a polar coordinate system that shows the distribution of echo intensities for each distance and direction based on the echo intensity signals for each distance and direction. Such distribution map generation processing by the monitoring computer 50 corresponds to a distribution map generation means. The monitoring computer 50 converts the generated distribution map into a video signal and outputs the video signal to the display device 52. The display device 52 displays the distribution map according to the video signal.

[0051] FIG. 3 is an explanatory diagram of a distribution diagram displayed on the display device 52. As shown in FIG. In Fig. 3, the dashed lines are auxiliary lines and are not displayed on the distribution map. This distribution map expresses the echo intensity for each distance and direction in gradations using the colors of the pixels. In this distribution section, the origin O represents the position of the sonar 21, the radial radius R centered on the origin O represents the distance, the axis Ax passing through the origin O represents the center line of the sound beam, and the central angle θ from the axis Ax represents the direction. The axis Ax extends in the vertical direction of the image. As described above, the distribution map is in a polar coordinate system, but the position of each pixel in the image of the distribution map is expressed in a Cartesian coordinate system.

[0052] If there is no inspection target such as a dam wall in front of the sonar 21, the echo intensity from any distance and direction is very low. Therefore, the distribution map will have a uniform color, as shown in FIG.

[0053] On the other hand, if an object to be inspected, such as a dam, is present in front of the sonar 21, the echo intensity from the distance and direction of the object to be inspected will be high. Therefore, as shown in Figs. 5 to 7, a linear image 80 in a color different from the colors of other parts is displayed on the distribution map. The linear image 80 represents the object to be inspected, and it is possible to know whether the underwater exploration robot 10 is facing the object to be inspected directly or facing the object obliquely from the inclination of the linear image 80 relative to the horizontal direction of the image. If the linear image 80 is parallel to the horizontal direction of the image as shown in Fig. 5, the underwater exploration robot 10 faces the object to be inspected directly as shown by the solid line in Fig. 8. If the linear image 80 rises to the right in the image as shown in Fig. 6, the underwater exploration robot 10 is tilted to the right around the vertical axis from the state of facing directly as shown by the two-dot chain line in Fig. 8. If the linear image 80 rises to the left in the image as shown in FIG. 7, then the underwater exploration robot 10 is tilted to the left around the up-down axis from the front facing state, as shown by the dashed line in FIG.

[0054] The sonar 21 operates periodically at a predetermined cycle, and detects the echo intensity for each distance and direction for each cycle. Therefore, the monitoring computer 50 generates a distribution map for each cycle and outputs the video signal to the display device 52, so that the distribution map displayed on the display device 52 changes for each cycle. Also, every time the sonar 21 detects the echo intensity for each distance and direction, the video signal of the distribution map of echo intensity transferred from the monitoring computer 50 to the pilot assistance computer 60 is updated.

[0055] The monitoring computer 50 outputs the video signal of the generated distribution map to the display device 52 as well as to the pilot assistance computer 60.

[0056] The above-mentioned functions of the monitoring computer 50 are realized by a program 53 a stored in the storage device 53 .

[0057] <Pilot assistance computer> The functions of the pilot assistance computer 60 are realized by a program 63a stored in the storage device 63. The flow of processes that the program 63a causes the pilot assistance computer 60 to execute will be described in detail later.

[0058] <Operation and usage of underwater exploration system> The operation and use of the underwater exploration system will now be described. An operator throws the underwater exploration robot 10 into water. The operator also operates the controller 40 to turn on the electronic camera 13b, the fisheye lens camera 14, the headlight 18, and the sonar 21. Then, an image of the foreground of the underwater exploration robot 10 captured by the electronic camera 13b is displayed on the display device 52, an image of the underwater exploration robot 10 captured by the fisheye lens camera 14 is displayed on the display device 52, and a distribution map of echo intensity is displayed on the display devices 52 and 62.

[0059] Then, the worker uses the controller 40 to operate the propulsion unit 15 of the underwater exploration robot 10. This causes the underwater exploration robot 10 to dive close to the inspection target 90. At this time, while checking the foreground image and distribution map displayed on the display device 52, the worker avoids obstacles so that the underwater exploration robot 10 does not hit the obstacles.

[0060] When the underwater exploration robot 10 approaches the inspection object 90, the worker operates the propulsion unit 15 of the underwater exploration robot 10 with the controller 40 to turn the rear of the underwater exploration robot 10 toward the inspection object 90 and bring the cleaning unit 17 into contact with the inspection object 90. Then, when the worker turns on the cleaning unit 17 with the controller 40, the cleaning unit 17 is activated and the deposits are peeled off from the inspection object 90 by the cleaning unit 17. At this time, the worker operates the propulsion unit 15 of the underwater exploration robot 10 with the controller 40 to make the underwater exploration robot 10 submerge along the inspection object 90. After cleaning is completed, the cleaning unit 17 is turned off.

[0061] Next, the worker uses the controller 40 to operate the propulsion unit 15 of the underwater exploration robot 10 to make the underwater exploration robot 10 submerge, space the underwater exploration robot 10 between the inspection object 90 and the underwater exploration robot 10, and orient the front of the underwater exploration robot 10 toward the inspection object 90. At this time, the worker looks at the display device 52 and determines the attitude of the underwater exploration robot 10 so that the roll angle and pitch angle of the underwater exploration robot 10 are zero degrees or an approximate value thereof.

[0062] Because the underwater exploration robot 10 is facing the object of inspection 90 directly, as shown in Figure 9, in the distribution map displayed on the display devices 52, 62, a linear image 81 representing the object of inspection 90 extends horizontally in the image.

[0063] Once the underwater exploration robot 10 is faced directly with the inspection target 90, the operator operates the input device 51 to cause the monitoring computer 50 to execute a video recording process. The monitoring computer 50 then converts the signal of the video captured by the electronic camera 13b into a predetermined video format and records the video in that format in the storage device 53. While recording the video, the monitoring computer 50 captures still images from the video captured by the electronic camera 13b at predetermined intervals and records the still images in the storage device 53. By recording such videos and still images in the storage device 53, the inspection target 90 can later be inspected for the presence or absence of cracks, etc.

[0064] During the shooting of the video, the worker uses the controller 40 to operate the propulsion unit 15 of the underwater exploration robot 10 to make the underwater exploration robot 10 dive along the inspection object 90. During the diving of the underwater exploration robot 10, there is a risk that the underwater exploration robot 10 may approach or move away from the inspection object 90 or yaw due to a water current or the like. If this happens, there is a risk that the scale of the image of the inspection object 90 in the video and still images may change or the image of the inspection object 90 may be distorted by trapezoid. In order to suppress such scale change and trapezoidal distortion, the operator's operation of the propulsion unit 15 of the underwater exploration robot 10 is assisted by the operation assistance computer 60. A specific description will be given below.

[0065] First, when the underwater exploration robot 10 is faced directly with the inspection target object 90 as described above, the operator operates the input device 63 to cause the operation assistance computer 60 to execute the program 63a having the processing flow as shown in Fig. 10. Alternatively, when the operator causes the monitoring computer 50 to execute a video recording process using the input device 61 as described above, the monitoring computer 50 transfers a program start signal to the operation assistance computer 60, and the operation assistance computer 60 executes the program 63a based on this signal.

[0066] Then, the piloting assistance computer 60 performs a capturing process on the video signal of the distribution map of echo intensity transferred from the monitoring computer 50, and captures an image of the distribution map (step S1). As explained with reference to FIG. 9, a linear image 81 in this distribution map image extends in the horizontal direction of the image. Hereinafter, the image of the distribution map in raster or vector format thus captured is referred to as a reference image. In addition, the position of the underwater exploration robot 10 when the reference image is captured is referred to as a reference position.

[0067] Next, the pilot assistance computer 60 extracts a linear image 81 by performing feature extraction processing such as edge detection processing on the reference image, and detects the linear image 81 as a line segment 81A (see FIG. 11) in a vector format (step S2). Hereinafter, this line segment 81A is referred to as a reference line segment 81A. The processing of step S2 by the pilot assistance computer 60 corresponds to a first detection means.

[0068] Thereafter, each time the image signal of the echo intensity distribution map transferred from the monitoring computer 50 to the pilot assistance computer 60 is updated, that is, each time the sonar 21 detects echo intensity for each distance and direction, the pilot assistance computer 60 executes the processing of steps S3 to S7.

[0069] In step S3, the piloting assistance computer 60 captures the image of the distribution map of echo intensity transferred from the monitoring computer 50 by performing a capturing process on the video signal of the distribution map of echo intensity. Hereinafter, the image in raster format or vector format thus captured is referred to as a comparison image. Hereinafter, if the underwater exploration robot 10 approaches or moves away from the inspection target 90 due to a water current or the like, or if it yaws, as shown in FIG. 12, a linear image 82 in the comparison image may be displaced in the vertical direction of the image from the position of the reference linear image 81, or may be tilted with respect to the reference linear image 81.

[0070] The process of the pilot assistance computer 60 in the next step S4 corresponds to the second detection means. In step S4, the pilot assistance computer 60 performs feature extraction processing such as edge detection processing on the comparison target image to extract a linear image 82 and detect the linear image 82 as a line segment 82A (see FIG. 13) in a vector format. Hereinafter, this line segment 82A will be referred to as a comparison target line segment 82A.

[0071] The process of the pilot assistance computer 60 in the next step S5 corresponds to a difference calculation means. In step S5, the pilot assistance computer 60 calculates the difference between the position of the reference line segment 81A and the position of the comparison target line segment 82A. Specifically, as shown in Fig. 14, the pilot assistance computer 60 calculates the inclination angle θ of the comparison target line segment 82A with respect to the reference line segment 81A, and the distance D along the vertical direction of the image from the midpoint 82B of the comparison target line segment 82A to the midpoint 81B of the reference line segment 81A.

[0072] Here, the inclination angle θ and the distance D can take positive and negative values, rather than absolute values. For example, if the midpoint 82B of the comparison target line segment 82A is located vertically above the midpoint 81B of the reference line segment 81A in the image, the distance D takes a positive value, and if the midpoint 82B of the comparison target line segment 82A is located vertically below the midpoint 81B of the reference line segment 81A in the image, the distance D takes a negative value. If the comparison target line segment 82A is inclined upward to the right with respect to the reference line segment 81A, the inclination angle θ takes a positive value, and if the comparison target line segment 82A is inclined upward to the left with respect to the reference line segment 81A, the inclination angle θ takes a negative value. These relationships may be reversed.

[0073] The processing of the pilot assistance computer 60 in the subsequent steps S6 and S7 corresponds to the pilot assistance means, the processing of the pilot assistance computer 60 in step S6 corresponds to the first and second correction value calculation means, and the processing of the pilot assistance computer 60 in step S7 corresponds to the first and second output means. In step S6, the pilot assistance computer 60 calculates a correction value for the yaw moment and a correction value for the thrust in the longitudinal direction based on the difference calculated in step S5. Specifically, the pilot assistance computer 60 calculates the correction value for the yaw moment from the tilt angle θ calculated in step S5, for example, the tilt angle θ and the correction value for the yaw moment are in a direct proportional relationship. In addition, the pilot assistance computer 60 calculates the correction value for the thrust in the longitudinal direction from the distance D calculated in step S5, for example, the distance D and the correction value for the thrust in the longitudinal direction are in a direct proportional relationship.

[0074] In step S7, the piloting assistance computer 60 outputs the correction value of the yaw moment calculated in step S6 to the control unit 22. The output of such a correction value corresponds to a command to correct the control of the propulsion unit 15 according to the signal of the controller 40. Therefore, the control unit 22 corrects the command value of the moment according to the displacement of the left and right turning operation lever of the controller 40 based on the correction value of the yaw moment. In other words, the control unit 22 adds the correction value of the yaw moment to the command value of the moment according to the displacement of the left and right turning operation lever of the controller 40, and controls the moment of the forward and rearward thrusters 15a according to the sum. Therefore, the piloting of the underwater exploration robot 10 by the operator is assisted, and the underwater exploration robot 10 yaws to return to a state facing the inspection target 90. As a result, the inclination angle θ calculated in the next step S6 approaches zero. For example, as shown in Fig. 14, when the comparison line segment 82A is inclined upward to the right with respect to the reference line segment 81A, that is, when the underwater exploration robot 10 is inclined to the right about the up-down axis from the front-facing state, the front-rear thruster 15a generates a moment to the left, and the underwater exploration robot 10 yaws to the left as indicated by arrow A in Fig. 15. Conversely, when the underwater exploration robot 10 is inclined to the left about the up-down axis from the front-facing state, the front-rear thruster 15a generates a moment to the right, and the underwater exploration robot 10 yaws to the right. The larger the yaw angle from the state in which the underwater exploration robot 10 faces the inspection object 90, the larger the yaw moment when the underwater exploration robot 10 returns to a state in which it faces the inspection object 90. This is because the inclination angle θ and the correction value of the yaw moment are directly proportional to each other.

[0075] In step S7, the piloting assistance computer 60 outputs the correction value of the forward / rearward propulsive force calculated in step S6 to the control unit 22. The output of such a correction value corresponds to a command to correct the control of the propulsion unit 15 according to the signal of the controller 40. The control unit 22 corrects the command value of the propulsive force according to the displacement of the forward / rear travel operation lever of the controller 40 based on the correction value of the forward / rearward propulsive force. That is, the control unit 22 adds the propulsive force correction value to the command value of the propulsive force according to the displacement of the forward / rear travel operation lever of the controller 40, and controls the forward / rear thruster 15a according to the sum, thereby controlling the propulsive force of the forward / rear thruster 15a to the sum. Therefore, the piloting of the underwater exploration robot 10 by the operator is assisted, and the underwater exploration robot 10 is propelled in the forward / rear direction so as to return to a certain distance from the inspection target 90. For example, as shown in FIG. 14, when the midpoint 82B of the comparison line segment 82A is located higher in the image than the midpoint 81B of the reference line segment 81A, that is, when the underwater exploration robot 10 deviates backward from the reference position, the underwater exploration robot 10 moves forward. Conversely, when the underwater exploration robot 10 deviates forward from the reference position, the underwater exploration robot 10 moves backward. As a result, the distance D calculated in the next step S6 approaches zero. Note that the greater the deviation of the distance from the underwater exploration robot 10 to the inspection object 90 from the fixed distance, the greater the propulsive force when the underwater exploration robot 10 returns to the fixed distance from the inspection object 90. This is because the distance D and the correction value of the forward / rearward propulsive force are in a directly proportional relationship.

[0076] 15, the underwater exploration robot 10 drifts, but if the underwater exploration robot 10 is not tilted from a straight-ahead state, the underwater exploration robot 10 propels forward and backward without yaw. If the underwater exploration robot 10 is not displaced forward or backward from a reference position, the underwater exploration robot 10 yaws without propelling forward and backward.

[0077] Thereafter, the pilot assistance computer 60 repeatedly executes the processes of steps S3 to S7. Therefore, the underwater exploration robot 10 is kept facing the inspection object 90 and is kept at a constant distance from the inspection object 90. Therefore, the scale of the image of the inspection object 90 in the video captured by the electronic camera 13b is kept constant and the image of the inspection object 90 is not distorted.

[0078] After starting the process shown in Fig. 10, if the operator operates the left / right travel control lever of the controller 40, the underwater exploration robot 10 will propel left / right. If the operator operates the up / down travel control lever of the controller 40, the underwater exploration robot 10 will propel up / down.

[0079] <Advantageous Effects> The above embodiment provides the following advantageous effects.

[0080] (1) Since the operation of the underwater exploration robot 10 is assisted by the operation assistance computer 60, the underwater exploration robot 10 is kept facing the inspection object 90, and the distance from the underwater exploration robot 10 to the inspection object 90 is kept constant. Therefore, the scale of the image of the inspection object 90 in the video is kept constant, and the image of the inspection object 90 is not distorted.

[0081] (2) The measurement results of the sonar 21 are used in the processing of the piloting assistance computer 60. Therefore, the sonar 21 can be effectively used for piloting the underwater exploration robot 10.

[0082] (3) The auxiliary piloting computer 60 is prepared separately from the monitoring computer 50, and the operation of the underwater exploration robot 10 is assisted by the auxiliary piloting computer 60, thereby reducing the processing load on the monitoring computer 50. If the processing capacity of the monitoring computer 50 is high, the above-mentioned processing of the auxiliary piloting computer 60 may be executed by the monitoring computer 50.

[0083] <Modification> In the above embodiment, the correction value for the yaw moment is calculated based on the inclination angle of the comparison target line segment 82A with respect to the reference line segment 81A, and the correction value for the forward / rearward thrust is calculated based on the distance along the vertical direction of the image from midpoint 82B to midpoint 82B. In contrast, the correction value for the yaw moment and the correction value for the forward / rearward thrust may be calculated by drawing perpendicular lines perpendicular to the reference line segment 81A from both ends of the comparison target line segment 82A to the reference line segment 81A, and then calculating the distances from the intersections of the perpendicular lines and the reference line segment 81A to both ends of the comparison target line segment 82A or the difference between these distances.

[0084] In the above embodiment, the sonar 10 that transmits a sound wave beam spreading in a fan shape to the left and right is used as the detection unit. Alternatively, an optical detection unit may be used as the detection unit. The optical detection unit transmits a light wave beam spreading in the left and right direction and narrowing in the up and down direction to the front, and detects the intensity of the reflected light for each distance and direction by receiving the reflected light from the front. Alternatively, the optical detection unit transmits a scanning beam spreading to the left and right to the front by irradiating a laser beam to the front and deflecting the laser beam to the left and right, and detects the intensity of the reflected light for each distance and direction by receiving the reflected light from the front. In this case, the signal of the reflected light intensity for each distance and direction is transferred from the optical detection unit to the monitoring computer 50 via the control unit 22. The monitoring computer 50 generates a distribution map of a polar coordinate system that shows the distribution of the reflected light intensity for each distance and direction based on the reflected light intensity signal for each distance and direction.

[0085] In the above embodiment, the monitoring computer 50 functions as the distribution map generating means, but the pilot assistance computer 60 may function as the distribution map generating means. In this case, the echo intensity signals for each distance and direction are transferred from the sonar 10 to the pilot assistance computer 60 via the control unit 22 and the monitoring computer 50. [Explanation of symbols]

[0086] 10... Underwater exploration robot (underwater submersible) 15...propulsion machine 21...Sonar (detection unit) 22...Control unit (control section) 40…Pilot 50...Monitoring computer (distribution map generating means) 60...pilot assistance computer (first detection means, second detection means, difference calculation means, pilot assistance means, first correction value calculation means, first output means, second correction value calculation means, second output means)

Claims

1. Underwater submersibles, The pilot and a propulsion device provided on the underwater submersible, the propulsion device generating a propulsive force for forward and reverse movement of the underwater submersible and generating a moment for yaw of the underwater submersible; A control unit that controls the propulsion unit in accordance with a signal from the controller; a detection unit provided in the underwater submersible, which transmits a beam spreading left and right toward the front of the underwater submersible, and periodically detects the intensity of the reflected wave for each distance and direction to the object to be inspected based on the reflected wave received from the object to be inspected in front of the underwater submersible; a distribution map generating means for generating an image including a distribution map showing the intensity of the reflected wave for each distance and direction in gradation every time the detection unit detects the intensity of the reflected wave for each distance and direction; a first detection means for detecting a reference line-shaped image representing the inspection object as a reference line segment in a distribution map in a predetermined image generated by the distribution map generation means; a second detection means for detecting a linear image of the comparison object representing the inspection object as a line segment of the comparison object in the distribution map in the comparison object image every time a comparison object image subsequent to the predetermined image is generated by the distribution map generation means; a difference calculation means for calculating a difference between the reference line segment and the comparison line segment each time the comparison line segment is detected by the second detection means; and a piloting assist means for instructing the control unit to correct the control of the propulsion unit in accordance with the signal from the controller based on the difference calculated by the difference calculation means each time the difference is calculated by the difference calculation means.

2. The steering assistance means is a first correction value calculation means for calculating a correction value of a yaw moment based on the difference calculated by the difference calculation means; a first output means for outputting the correction value calculated by the first correction value calculation means to the control unit, The control unit adds the correction value output by the first output means to a command value of the moment represented by the signal of the controller, and controls the propulsion unit to generate a moment according to the sum.

2. The underwater submersible system of claim 1.

3. The difference calculation means calculates an inclination angle of the comparison target line segment with respect to the reference line segment as a difference between the reference line segment and the comparison target line segment.

3. The underwater submersible system of claim 2.

4. The steering assistance means is a second correction value calculation means for calculating a correction value of a front and rear thrust based on the difference calculated by the difference calculation means; and second output means for outputting the correction value calculated by the second correction value calculation means to the control unit, The control unit adds the correction value output by the second output means to a command value of forward and backward thrust represented by a signal from the controller, and controls the propulsion unit to generate a forward and backward thrust according to the sum. An underwater submersible system according to any one of claims 1 to 3.

5. The difference calculation means calculates the distance from a midpoint of the comparison target line segment to a midpoint of the reference line segment as a difference between the reference line segment and the comparison target line segment.

5. The underwater submersible system of claim 4.

6. a propulsion device that generates a propulsive force for forward and backward movement of the underwater submersible and a moment for yaw of the underwater submersible is provided on the underwater submersible, A detection unit is provided in the underwater submersible for transmitting a beam spreading left and right toward the front of the underwater submersible and periodically detecting the intensity of the reflected wave for each distance and direction to the object to be inspected based on the reflected wave received from the object to be inspected in front of the underwater submersible, A piloting assist device that controls a control unit that controls the propulsion unit according to a signal from a pilot, The steering assist device is a distribution map generating means for generating an image including a distribution map showing the intensity of the reflected wave for each distance and direction in gradation every time the detection unit detects the intensity of the reflected wave for each distance and direction; a first detection means for detecting a reference line-shaped image representing the inspection object as a reference line segment in a distribution map in a predetermined image generated by the distribution map generation means; a second detection means for detecting a linear image of the comparison object representing the inspection object as a line segment of the comparison object in the distribution map in the comparison object image every time a comparison object image subsequent to the predetermined image is generated by the distribution map generation means; a difference calculation means for calculating a difference between the reference line segment and the comparison line segment each time the comparison line segment is detected by the second detection means; a control assist means for instructing the control unit to correct the control of the propulsion unit in accordance with a signal from the controller, based on the difference calculated by the difference calculation means, each time the difference is calculated by the difference calculation means; and A piloting assistance device comprising:

7. The steering assist device according to claim 6, The steering assistance means is a correction value calculation means for calculating a correction value of a yaw moment based on the difference calculated by the difference calculation means; an output unit that outputs the correction value calculated by the correction value calculation unit to the control unit, The control unit adds the correction value output by the output means to a command value of the moment represented by the signal of the controller, and controls the propulsion unit to generate a moment according to the sum. Pilot aids.

8. a propulsion device that generates a propulsive force for forward and backward movement of the underwater submersible and a moment for yaw of the underwater submersible is provided on the underwater submersible, A detection unit is provided in the underwater submersible for transmitting a beam spreading left and right toward the front of the underwater submersible and periodically detecting the intensity of the reflected wave for each distance and direction to the object to be inspected based on the reflected wave received from the object to be inspected in front of the underwater submersible, A computer that controls a control unit that controls the propulsion unit in accordance with a signal from a controller, a distribution map generating means for generating an image including a distribution map showing the intensity of the reflected wave for each distance and direction in gradations each time the detection unit detects the intensity of the reflected wave for each distance and direction; a first detection means for detecting a reference linear image representing the inspection object as a reference line segment in a distribution map in a predetermined image generated by the distribution map generation means; a second detection means for detecting a linear image of the comparison object, which represents the inspection object, as a line segment of the comparison object in the distribution map in the comparison object image each time a comparison object image subsequent to the predetermined image is generated by the distribution map generation means; a difference calculation means for calculating a difference between the reference line segment and the comparison target line segment each time the comparison target line segment is detected by the second detection means; a control assist means for instructing the control unit to correct the control of the propulsion unit in accordance with the signal from the controller, based on the difference calculated by the difference calculation means, each time the difference is calculated by the difference calculation means; A program that functions as a

9. The program according to claim 8, The program causes the computer functioning as the piloting assistance means to a correction value calculation means for calculating a correction value for a yaw moment based on the difference calculated by the difference calculation means; an output means for outputting the correction value calculated by the correction value calculation means to the control unit; Function as a The control unit adds the correction value output by the output means to a command value of the moment represented by the signal of the controller, and controls the propulsion unit to generate a moment according to the sum. program.

Images