JP6580741B1 - Position detection system and position detection method - Google Patents

Abstract

A position detection system and a position detection method are provided that can appropriately detect the position of a target object even in an environment in which sound waves and ultrasonic waves are reflected. A position detection device that floats on a liquid stored in a tank and detects a position of a target object in the liquid is provided, and the position detection device rotates about a rotation axis in a direction intersecting a liquid surface of the liquid. While irradiating the inner peripheral surface of the tank with laser light and receiving the irradiated laser light, the laser measuring device that acquires the point cloud data indicating the measurement result of the distance to the inner peripheral surface, and the acquired points A position detection unit that determines a specific position in the region surrounded by the group data as an origin of the position detection device, and detects a position of the target object based on the determined origin. [Selection] Figure 1

Description

  Embodiments according to the present invention relate to a position detection system and a position detection method.

  Conventionally, as a technology for detecting the position of a target object such as an underwater Rov (Remotely Operated Vehicle) or a diver, an acoustic device (sonar) or an ultrasonic measurement device is used to irradiate the water with sound waves or ultrasonic waves from the ship. Therefore, a technique for detecting the position of a target object existing in water has been adopted.

  Such a conventional technique can be sufficiently applied to an environment where sound waves and ultrasonic waves such as the sea and a concrete wall do not resonate.

  However, when the conventional technology is applied to an environment where sound waves and ultrasonic waves are reflected in a tank covered with metal, etc., the detection wave is stabilized by the influence of the sound waves and ultrasonic waves reflected on the tank wall. Therefore, there are problems such that the position of the target object cannot be detected properly, and the underwater Rov collides with the tank.

Japanese Patent Laid-Open No. 9-61513

  The present invention has been made to solve the above-described problems, and can appropriately detect the position of a target object even in an environment in which sound waves and ultrasonic waves resonate, and can also detect an underwater Rov due to a collision with a tank or the like. It is an object of the present invention to provide a position detection system and a position detection method that can prevent damage to the apparatus.

  The position detection system according to the present embodiment includes a position detection device that floats on the liquid stored in the tank and detects the position of the target object in the liquid. The position detection device includes a laser measurement device and a position detection unit. The laser measuring device irradiates the inner peripheral surface of the tank with laser light while rotating around the rotation axis in the direction intersecting the liquid surface of the liquid, and receives the irradiated laser light to obtain a distance to the inner peripheral surface. Point cloud data indicating the measurement result is obtained. The position detection unit determines a specific position in the region surrounded by the acquired point cloud data as the origin of the position detection device, and detects the position of the target object with reference to the determined origin.

  According to the present invention, it is possible to appropriately detect the position of a target object even in an environment in which sound waves and ultrasonic waves are reflected.

It is a block diagram which shows the position detection system by this embodiment. It is a top view which shows the position detection system by this embodiment. FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2 illustrating the position detection system according to the present embodiment. It is a side view which shows the position detection unit in the position detection system by this embodiment. It is a top view which shows the position detection unit in the position detection system by this embodiment. It is a flowchart which shows the position detection method by this embodiment. In the position detection method by this embodiment, it is a side view of the position detection unit which shows the acquisition process of point cloud data. It is a top view which shows the determination process of an origin in the position detection method by this embodiment. In the position detection method by this embodiment, it is a top view which shows the detection process of the position of the position detection unit on the basis of the origin, and the detection process of the relative position of underwater Rov with respect to a position detection unit. In the position detection method by this embodiment, it is a top view which shows the detection process of the position of underwater Rov on the basis of the origin. In the position detection method by this embodiment, it is a top view which shows the correction process of the relative position of underwater Rov based on detection depth. In the position detection method by this embodiment, it is a top view which shows the re-detection process of the position of underwater Rov on the basis of the origin. In the position detection method by the 1st modification of this embodiment, it is a top view which shows the re-detection process of the position of underwater Rov on the basis of the origin. It is a block diagram which shows the position detection system by the 2nd modification of this embodiment. It is a side view which shows the position detection unit in the position detection system by the 2nd modification of this embodiment. It is a block diagram which shows the position detection system by the 3rd modification of this embodiment. It is a flowchart which shows the position detection method by the 4th modification of this embodiment. It is a top view which shows the position detection system by the 5th modification of this embodiment. It is IX-IX sectional drawing of FIG. 18 which shows the position detection system by the 5th modification of this embodiment. It is a flowchart which shows the position detection method by the 5th modification of this embodiment. In the position detection method by the 5th modification of this embodiment, it is a top view which shows the determination process of the angle of a position detection unit, and the calculation process of the position on the basis of the origin. In the position detection method by the 6th modification of this embodiment, it is a top view which shows the measurement distance between light-emitting bodies. In the position detection method by the 6th modification of this embodiment, it is a side view which shows the distance from a position detection unit to underwater Rov. In the position detection method by the 6th modification of this embodiment, it is a top view which shows the distance between the light-emitting bodies on a captured image.

  Embodiments according to the present invention will be described below with reference to the drawings. The embodiments do not limit the present invention.

  First, the position detection system according to the present embodiment will be described with reference to FIGS. FIG. 1 is a block diagram showing a position detection system 1 according to the present embodiment. FIG. 2 is a plan view showing the position detection system 1 according to the present embodiment. FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2 showing the position detection system 1 according to the present embodiment. FIG. 4 is a side view showing the position detection unit 20 in the position detection system 1 according to the present embodiment. FIG. 5 is a plan view showing the position detection unit 20 in the position detection system 1 according to the present embodiment.

  For example, as shown in FIG. 3, the position detection system 1 detects the position of a target object existing in the water 10 stored in the tank 9 and the position of an underwater Rov 3 that is an example of a moving body in the water 10. It can be used for detection by the unit 20. The underwater Rov 3, which is a remotely operated unmanned submersible, dives and images the inside of the tank 9 in order to detect, for example, deterioration of the tank 9. The tank 9 is made of metal.

  As shown in FIG. 1, the position detection system 1 includes a position detection device 2, a light emitter 4 that indicates the direction of movement of the underwater Rov 3 and the underwater Rov 3, an underwater Rov power supply unit 7, and an underwater Rov PC 8. Is provided. In the example of FIG. 1, the number of light emitters 4 is three, but the number of light emitters 4 may be four or more. The position detection device 2 is a device that floats on the water 10 stored in the tank 9 and detects the position of the underwater Rov 3 in the water. The position detection device 2 includes a position detection unit 20, a position detection power supply unit 5, and a position detection PC 6 which is an example of a position detection unit and a display device.

  The position detection unit 20 floating in the water 10 in the tank 9 is connected to the position detection power supply unit 5 and the position detection PC 6 arranged on the ground side by a cable 11. 2 and 3, the position detection unit 20 is thrown into the water through a tank manhole 91 that partially penetrates the top plate 90 of the tank 9. In the example of FIG. 3, the position detection unit 20 is thrown into the water in a state of being suspended by a suspension device 92 disposed at the upper end of the tank manhole 91.

  The position detection power supply unit 5 supplies power to the position detection unit 20 via the cable 11.

  The position detection PC 6 receives, from the position detection unit 20 via the cable 11, the detection result of the position of the position detection unit 20 based on the origin described later, and the detection result of the relative position of the underwater Rov 3 with respect to the position detection unit 20. Receive. Further, the position detection PC 6 receives the detection result of the depth of the underwater Rov 3 by the depth sensor 31 described later from the underwater Rov PC 8. Then, the position detection PC 6 calculates (detects) the position of the underwater Rov 3 based on the origin described later, based on the received detection results. Then, the position detection PC 6 displays the calculated position of the underwater Rov 3 as an image and a numerical value on the XY coordinate system on the monitor screen.

  The underwater Rov 3 that works while diving in the tank 9 is connected to the underwater Rov power supply unit 7 and the underwater Rov PC 8 that are arranged on the ground side via a cable 12.

  The underwater Rov power supply unit 7 supplies power to the underwater Rov 3 via the cable 12.

  The underwater Rov PC 8 receives, from the underwater Rov3 via the cable 12, a captured image inside the tank 9 by a camera 33 (to be described later) and a detection result of the depth of the underwater Rov3 by a depth sensor 31 (to be described later). The underwater Rov PC 8 transmits the received underwater Rov3 depth detection result to the position detection PC 6.

  Hereinafter, the position detection unit 20 will be described in detail. As illustrated in FIG. 1, the position detection unit 20 includes a laser unit 21 that is an example of a laser measurement device, a position detection CPU 22 that is an example of a position detection unit, a camera 23 that is an example of an imaging device, and a moving device. A moving thruster 24, a CPU 25, a thruster activation unit 26, a horizontality confirmation acceleration sensor 27, and a power source separation unit 28. Further, as shown in FIGS. 4 and 5, the position detection unit 20 includes an acceleration sensor 27 for checking the level, a frame 210, and a buoyancy body 211.

  4 and 5, the position detection unit 20 has four rod-shaped frames 210 that intersect in a cross shape, and the laser unit 21 and the camera 23 are vertically moved at the intersecting positions of the frames 210. The buoyancy body 211 and the moving thruster 24 are disposed on the opposite side of the crossing position of each frame 210.

  The laser unit 21 includes a laser distance meter 21a and a control unit 21b that controls the laser distance meter 21a. The laser unit 21 irradiates the laser distance meter 21a (not shown) while rotating 360 ° around a rotation axis in a direction substantially orthogonal (that is, intersecting) the water surface 10a in a state of floating in water by the buoyancy of the buoyancy body 211. The laser beam is irradiated from the portion to the inner peripheral surface 9a. The laser unit 21 receives the laser light applied to the inner peripheral surface 9a by a light receiving unit (not shown) of the laser distance meter 21a, so that the distance from the position detection unit 20 (that is, the position detection device 2) to the inner peripheral surface 9a. Point cloud data indicating the measurement result is obtained.

  In the example shown in FIG. 4, the laser unit 21 is located above the water surface 10 a without being immersed in the water 10 in a state where the position detection unit 20 is floating in the water 10. Since the laser unit 21 is positioned above the water surface 10a in this way, the laser unit 21 can irradiate and receive laser light in the air, so that the distance to the inner peripheral surface 9a of the tank 9 can be accurately determined. The point cloud data shown can be obtained.

  The camera 23 images the underwater Rov3 at a predetermined viewing angle. In the example of FIG. 3, the camera 23 is disposed on the frame 210 so that the optical axis faces vertically downward in a state where the position detection unit 20 is suspended in the water 10. The viewing angle of the camera 23 indicated by a broken line in FIG. 3 may be 120 °, for example, but is not limited thereto.

  The moving thruster 24 moves the position detection unit 20 on the water surface 10 a so that the underwater Rov 3 is captured within the viewing angle of the camera 23. In the example of FIG. 1, starting and stopping of the moving thruster 24 is executed by the thruster starting unit 26. In the example of FIGS. 1 and 2, the three light emitters 4 mounted on the underwater Rov 3 are arranged in a triangular shape so as to indicate the moving direction of the underwater Rov 3 indicated by the arrow A in FIG. The thruster activation unit 26 is a position detection unit that moves toward the moving direction A specified by the image of the light emitter 4 when the position of the image of the light emitter 4 in an image captured by the camera 23 (described later) of the underwater Rov 3 changes. The moving thruster 24 is activated so that 20 moves. Thereby, the position detection unit 20 can be moved so as to follow the movement of the underwater Rov3, and the underwater Rov3 can be continuously captured within the viewing angle of the camera 23. The movement of the position detection unit 20 for continuously capturing the underwater Rov3 within the viewing angle of the camera 23 may be manually performed by an operator while confirming the captured image of the camera 23.

  The position detection CPU 22 determines the origin of the position detection unit 20 (that is, the position detection device 2) based on the point cloud data acquired by the laser unit 21. More specifically, the position detection CPU 22 determines a specific position in the region surrounded by the point cloud data acquired by the laser unit 21 as the origin of the coordinates (position) of the position detection unit 20. For example, the origin may be the center point of the area surrounded by the point cloud data, that is, the center of the tank 9. Then, the position detection CPU 22 executes a process for detecting the position of the underwater Rov 3 with the determined origin as a reference.

  Specifically, the position detection CPU 22 detects the position of the position detection unit 20 based on the origin in accordance with the movement of the position detection unit 20 by the movement thruster 24. More specifically, the position detection CPU 22 compares the position of the position detection unit 20 in the area surrounded by the point cloud data acquired by the laser unit 21 after movement by the movement thruster 24 with the origin. The position of the position detection unit 20 with respect to the origin is detected.

  The position detection CPU 22 captures an underwater Rov3 image captured by the camera 23 via the CPU 25, and detects the relative position of the underwater Rov3 relative to the position detection unit 20 based on the captured underwater Rov3 captured image. More specifically, the position detection CPU 22 recognizes the blinking of the light emitter 4 through the underwater Rov3 captured image by the camera 23, and performs image processing on the underwater Rov3 captured image captured through the CPU 25, thereby performing position processing. The relative position of the underwater Rov 3 with respect to the detection unit 20 is detected. Then, the position detection CPU 22 synthesizes the detected relative position of the underwater Rov 3 and the position of the position detection unit 20 based on the origin detected based on the point cloud data acquired by the laser unit 21. Then, the position of the underwater Rov3 with respect to the origin is detected. However, the correction of the relative position of the underwater Rov3 based on the detection result of the depth sensor 31, which will be described later, is not added to the position of the underwater Rov3 based on the origin detected using the position detection CPU 22. As will be described later, the position detection device 1 uses the position detection PC 6 to correct the position of the underwater Rov3 with respect to the origin by taking into account the correction of the relative position of the underwater Rov3 based on the detection result of the depth sensor 31. To detect.

  The position detection CPU 22 transmits the detection result of the position detection unit 20 with reference to the origin and the detection result of the position of the underwater Rov 3 with reference to the origin to the position detection PC 6 via the cable 11.

  The position detection PC 6 displays the position of the position detection unit 20 with reference to the origin transmitted from the position detection CPU 22 and the position of the underwater Rov 3 with reference to the origin.

  The horizontality confirmation acceleration sensor 27 confirms whether or not the position detection unit 20 is parallel or horizontal to the water surface 10a when the position detection unit 20 is thrown into the water. When the position detection unit 20 is not parallel to the water surface 10a, the suspension device 92 adjusts the inclination of the position detection unit 20 until it is confirmed by the acceleration sensor 27 for levelness confirmation to be parallel. To do.

  The CPU 25 controls the operations of the components 21 to 24, 26 and 27 of the position detection unit 20 in an integrated manner.

  The power supply separation unit 28 distributes the power supplied from the position detection power supply unit 5 to the components 21 to 27 of the position detection unit 20.

  Hereinafter, the underwater Rov3 will be described in detail. As illustrated in FIG. 1, the underwater Rov 3 includes a depth sensor 31, which is an example of a depth meter, a marker control unit 32, a camera 33, a CPU 34, and a power supply separation unit 35.

  The depth sensor 31 is mounted on the underwater Rov3 and detects the depth of the underwater Rov3 in water. The depth sensor 31 is a pressure type depth sensor. By adopting the pressure type depth sensor 31 instead of the magnetic type depth sensor, it is possible to accurately detect the depth of the underwater Rov 3 without being affected by the reflection of the metal tank 9.

  The depth sensor 31 transmits the detection result of the depth of the underwater Rov 3 to the underwater Rov PC 8 via the cable 12. The underwater Rov PC 8 transfers the transmitted depth detection result to the position detection PC 6.

  The position detection PC 6 corrects the relative position of the underwater Rov 3 with respect to the position detection unit 20 based on the depth detection result. More specifically, the position detection PC 6 follows the water surface 10a between the position detection unit 20 (that is, the position detection device 2) and the underwater Rov3 based on the image of the light emitter 4 in the captured image of the underwater Rov3. The distances in the X and Y directions (substantially parallel) and the Z direction intersecting (substantially orthogonal) the water surface 10a are detected. Then, the position detection PC 6 corrects each distance in the X and Y directions with a correction coefficient corresponding to an error between the detected distance in the Z direction and the depth detected by the depth sensor 31, so that the underwater Rov 3 Correct the relative position. Then, the position detection PC 6 re-detects the position of the underwater Rov3 with respect to the origin by combining the corrected relative position of the underwater Rov3 with the position of the position detection unit 20 with respect to the origin. Then, the position detection PC 6 re-displays the position of the underwater Rov 3 with the re-detected origin as a reference together with the position of the position detection unit 20 with the origin as a reference.

  The marker control unit 32 controls the driving of the light emitter 4 so that the light emitter 4 blinks.

  The camera 33 images the inside of the tank 9. The camera 33 transmits the captured image inside the tank 9 to the underwater Rov PC 8 via the cable 12.

  The CPU 25 controls the operations of the constituent units 31 to 33 of the underwater Rov 3 in an integrated manner.

  The power supply separation unit 35 distributes the power supplied from the underwater Rov power supply unit 7 to the components 31 to 34 of the underwater Rov3.

(Position detection method)
Next, an example of a position detection method according to this embodiment to which the above-described position detection system 1 is applied will be described with reference to FIGS. FIG. 6 is a flowchart showing the position detection method according to this embodiment. FIG. 7 is a side view of the position detection unit 20 showing the point cloud data acquisition step in the position detection method according to the present embodiment.

  First, as a pre-stage of each step shown in FIG. 6, as shown in FIG. 3, the position detection unit 20 is suspended from the tank manhole 91 inside the tank 9 by the suspension device 92. 20 is put into water. At this time, the level check acceleration sensor 27 checks whether or not the position detection unit 20 is horizontal with respect to the water surface 10a. If the position detection unit 20 is not level, the suspension device 92 is level. The inclination of the position detection unit 20 is adjusted.

  Then, as shown in FIG. 7, the laser unit 21 is 360 in a rotation direction R around a rotation axis that is substantially orthogonal to the water surface 10a at a position where the position detection unit 20 is thrown into water, that is, immediately below the tank manhole 91. While rotating, the inner circumferential surface 9a of the tank 9 is irradiated with the laser light L along the circumferential direction. The laser unit 21 receives the laser light L irradiated to the inner peripheral surface 9a, and measures the distance from the position detection unit 20 to the inner peripheral surface 9a based on the time from the irradiation of the laser light L to the light reception. . Then, as shown in FIG. 6, the laser unit 21 acquires point cloud data indicating the distance measurement result (step S1).

  FIG. 8 is a plan view showing an origin determination step in the position detection method according to the present embodiment. After acquiring the point cloud data, as shown in FIGS. 8 and 6, the position detection CPU 22 calculates the center position of the tank 9 in the region surrounded by the acquired point cloud data d0 (step S2). The calculated center position of the tank 9 is determined as the origin (0, 0) of the position detection unit 20 (step S3).

  Further, as shown in FIG. 6, the moving thruster 24 moves the position detecting unit 20 automatically or manually to a position where the light emitter 4 mounted on the underwater Rov 3 is captured within the viewing angle of the camera 23 (step). S11). Since this process is always performed, the flowchart of FIG. 6 illustrates the process as a process parallel to steps S1 to S10.

  After determining the origin, as shown in FIG. 6, the camera 23 of the position detection unit 20 images the light emitter 4 of the underwater Rov 3 (step S4). FIG. 9 is a plan view showing a position detection process of the position detection unit 20 with respect to the origin and a detection process of the relative position of the underwater Rov 3 with respect to the position detection unit 20 in the position detection method according to the present embodiment. The imaging of the light emitter 4 is performed after the position detection unit 20 is moved to a position where the light emitter 4 is captured, as shown in FIG.

  After imaging the light emitter 4, as shown in FIG. 6, the position detection CPU 22, the position of the position detection unit 20 in the region surrounded by the point cloud data acquired by the laser unit 21 after the movement, the origin, To calculate the position of the position detection unit 20 with reference to the origin (0, 0) (step S5). In the example of FIG. 9, the laser unit 21 acquires the point cloud data d1 at the position after being moved by the moving thruster 24 by the same method as in step S1. Then, the position detection CPU 22 determines the origin (0, 0) based on the difference between the X direction and the Y direction with respect to the origin (0, 0) of the current position of the position detection unit 20 in the area surrounded by the point cloud data d1. Is used to calculate the position (x1, y1) of the position detection unit 20.

  After calculating the position (x1, y1) of the position detection unit 20 with the origin (0, 0) as a reference, the position detection CPU 22 performs image processing on the captured image of the light emitter 4 as shown in FIG. Thus, the relative position of the underwater Rov 3 with respect to the position detection unit 20 is calculated (step S6). In the example of FIG. 9, the position detection CPU 22 determines the relative position of the underwater Rov 3 based on the image of the light emitter 4, the distance x in the X direction of the light emitter 4 with respect to the camera 23, the distance −y in the Y direction, and the Z direction. The distance zi is calculated as a combination (x, -y, zi). In the example of FIG. 9, since the position of the underwater Rov3 exists in the −Y direction with respect to the position (x1, y1) of the position detection unit 20, the Y coordinate of the underwater Rov3 is a negative value. As shown in FIG. 9, the position detection CPU 22 may calculate the azimuth θ of the underwater Rov 3 with respect to the position detection unit 20 with the X direction as a reference.

  After calculating the relative position of the underwater Rov 3 with respect to the position detection unit 20, as shown in FIG. 6, the position detection CPU 22 determines the position of the position detection unit 20 relative to the origin and the relative position of the underwater Rov 3 with respect to the position detection unit 20. By combining the position, the position of the underwater Rov3 with respect to the origin is calculated (step S7). FIG. 10 is a plan view showing a detection process of the position of the underwater Rov relative to the origin in the position detection method according to the present embodiment. In the example of FIG. 10, the position detection CPU 22 uses the position (x1, y1) of the position detection unit 20 relative to the origin (0, 0) and the relative position (x, −y) of the underwater Rov 3 with respect to the position detection unit 20. ) And the position (x1 + x, y1-y) of the underwater Rov3 with respect to the origin (0, 0).

  After the position of the underwater Rov3 with respect to the origin is calculated, as shown in FIG. 6, the position detection PC 6 performs the position of the position detection unit 20 with respect to the origin and the position of the underwater Rov3 with respect to the origin. Are acquired from the position detection unit 20 and displayed (step S8).

  After displaying the position of the position detection unit 20 relative to the origin and the position of the underwater Rov3 relative to the origin, the position detection PC 6 detects the underwater Rov3 detected by the depth sensor 31, as shown in FIG. Based on the depth, the relative position of the underwater Rov3 with respect to the position detection unit 20 is corrected (step S9).

  FIG. 11 is a plan view illustrating a process of correcting the relative position of the underwater Rov based on the detection depth in the position detection method according to the present embodiment. In the example of FIG. 11, the position detection PC 6 is a correction coefficient corresponding to an error between the distance in the Z direction between the position detection unit 20 and the underwater Rov3 and the depth of the underwater Rov3, and the X between the position detection unit 20 and the underwater Rov3. The relative position of the underwater Rov3 is corrected by correcting the respective distances in the Y direction.

  More specifically, the position detection PC 6 replaces the relative position of the underwater Rov 3 in the Z direction with the depth zd detected by the depth sensor 31 from the relative position zi calculated based on the image of the light emitter 4.

  Further, the position detection PC 6 determines the relative position in the X direction of the underwater Rov 3 from the relative position x calculated based on the image of the illuminant 4, and a coefficient α proportional to the ratio zd / zi between zd and zi x Replace with the value αx multiplied by. The coefficient α may be the ratio zd / zi itself, or may be larger or smaller than the ratio zd / zi.

  Further, the position detection PC 6 calculates the coefficient β proportional to the ratio zd / zi between zd and zi from the relative position -y calculated based on the image of the light emitter 4 by calculating the relative position in the Y direction of the underwater Rov3. Replace with -y multiplied by -y. The coefficient β may be the same as or different from the coefficient α.

  In this way, the relative position of the underwater Rov 3 with respect to the position detection unit 20 is corrected from the relative position (x, −y, zi) before correction to the relative position (αx, −βy, zi) after correction.

  After correcting the relative position of the underwater Rov3, as shown in FIG. 6, the position detection PC 6 determines the position of the position detection unit 20 with respect to the origin and the corrected relative position of the underwater Rov3 in the X and Y directions. , The position of the underwater Rov3 with respect to the origin is recalculated and redisplayed (step S10).

  FIG. 12 is a plan view showing a step of re-detecting the position of the underwater Rov relative to the origin in the position detection method according to the present embodiment. In the example of FIG. 12, the position detection PC 6 uses the position (x1, y1) of the position detection unit 20 with reference to the origin (0, 0) and the relative position (αx) of the corrected underwater Rov3 in the X and Y directions. , -Βy). Through the synthesis, the position detection PC 6 recalculates the position (x2, y2) of the underwater Rov3 with the origin (0, 0) as a reference. The position (x2, y2) of the underwater Rov3 with respect to the origin (0, 0) can be expressed as (x1 + αx, y1−βy).

(Function)
Hereinafter, the operation brought about by the present embodiment will be described.

  As described above, in the position detection system 1 according to the present embodiment, the position detection device 2 includes the laser unit 21, the position detection CPU 22, and the position detection PC 6. The laser unit 21 irradiates the inner peripheral surface 9a of the tank 9 with the laser light L while rotating around the rotation axis in the direction intersecting the liquid surface 10a, and receives the irradiated laser light L, thereby receiving the inner peripheral surface. Point cloud data indicating the measurement result of the distance to 9a is acquired. The position detection CPU 22 determines a specific position in the region surrounded by the acquired point cloud data as the origin of the position detection unit 20. The position detection PC 6 detects the position of the underwater Rov 3 with reference to the determined origin.

  According to such a configuration, the origin of the position detection unit 20 serving as a reference for the position of the underwater Rov3 is based on point cloud data acquired by irradiation with laser light that does not generate echo waves such as sound waves and ultrasonic waves. It can be determined with high accuracy. By determining the origin with high accuracy, it is possible to appropriately detect the position of the underwater Rov 3 even in an environment where sound waves and ultrasonic waves are reflected. Further, by rotating the laser unit 21 itself, it is possible to acquire highly accurate point cloud data as compared with a device that rotates only the laser reflecting mirror. Thereby, the origin can be detected with higher accuracy and the positional accuracy of the underwater Rov3 can be improved. In addition, by using the laser unit 21, it is possible to quickly acquire point cloud data using a cheaper device than when acquiring point cloud data using a 3D measuring device.

  In the position detection system 1 according to the present embodiment, the position detection device 2 further includes a camera 23 and a moving thruster 24. The camera 23 images the underwater Rov3 at a predetermined viewing angle. The moving thruster 24 moves the position detection unit 20 on the water surface 10a so that the underwater Rov3 is captured within the viewing angle. The position detection CPU 22 detects the position of the underwater Rov3 based on the origin based on the captured image of the underwater Rov3.

  Here, when the position detection of the target object by the acoustic device or the ultrasonic device is applied to the position detection of the underwater Rov 3 in the tank 9, both the acoustic device or the ultrasonic device and the underwater Rov 3 are a transmitter and a receiver. It is necessary to carry out two-way reception. In this case, since the metal tank 9 is nearby, the receiver receives the reflected wave from the tank 9, and the position of the underwater Rov3 cannot be detected stably.

  In addition, a method of detecting a position of the underwater Rov3 by one-way reception by installing a receiver that outputs sound waves in order to prevent a reflected wave due to metal and mounting a receiver on the underwater Rov3 is expensive, and the underwater Rov3 Since the influence of the reflected wave cannot be completely removed when the distance is close to the inner peripheral surface 9a of the tank 9, the positional accuracy becomes insufficient.

  In addition, when the position of the underwater Rov 3 is detected by ultrasonic waves using a sound wave transmitter and a receiver, and errors due to reverberation occurring in the tank 9 are removed by a program, the sound wave transmitter, the receiver, and the tank 9 Since the echo changes depending on the distance to the peripheral surface 9a, it takes time to remove the error. Further, when the underwater Rov3 is located in the vicinity of the inner peripheral surface 9a, it becomes difficult to remove an error due to reverberation.

  On the other hand, according to the present embodiment, the position of the underwater Rov3 with respect to the origin is detected with high accuracy based on the captured image of the camera 23 that does not generate an echo wave as in the case of sound waves and ultrasonic waves. be able to. Further, even if the underwater Rov3 as a moving body moves in the tank 9, the position detection unit 20 can be moved so that the underwater Rov3 is captured within the viewing angle of the camera 23 by the moving thruster 24. The position can be continuously detected without losing sight of the underwater Rov3.

  In the position detection system 1 according to the present embodiment, the position detection CPU 22 includes the position of the position detection unit 20 in the region surrounded by the point cloud data acquired by the laser unit 21 after the movement by the movement thruster 24, and By comparing with the origin, the position of the position detection unit 20 with respect to the origin is detected. Further, the position detection CPU 22 detects the relative position of the underwater Rov 3 with respect to the position detection unit 20 based on the captured image of the underwater Rov 3 by the camera 23. Then, the position detection PC 6 detects the position of the underwater Rov3 with respect to the origin by combining the position of the position detection unit 20 with respect to the detected origin and the detected relative position of the underwater Rov3. To do.

  According to such a configuration, by combining the position of the position detection unit 20 with the origin acquired by laser irradiation as a reference and the relative position of the underwater Rov 3 with respect to the position detection unit 20 acquired by imaging, the echo is reflected. The position of the underwater Rov 3 with respect to the origin can be easily and appropriately detected without generating a wave.

  Moreover, the position detection system 1 according to the present embodiment includes a flashing light emitter 4 mounted on the underwater Rov 3. The position detection CPU 22 detects the relative position of the underwater Rov 3 with respect to the position detection unit 20 based on the captured image of the light emitter 4 in the captured image of the underwater Rov 3.

  Here, when detecting underwater Rov3 using an infrared camera, since infrared rays attenuate in water, it is difficult to detect underwater Rov3 working at a deep water position. In addition, when measuring the distance to underwater Rov3 with an underwater laser rangefinder, it is not possible to know where the measurement is performed in a tank or internal tank that does not have an internal structure. It is difficult to mount these instruments on the small underwater Rov3.

  On the other hand, according to the present embodiment, the relative position of the underwater Rov3 is detected with high accuracy with a simple configuration by detecting the relative position of the underwater Rov3 based on the captured image of the flashing light emitter 4. Can do.

  In the position detection system 1 according to the present embodiment, the three or more light emitters 4 are arranged in a triangular shape, for example, so as to indicate the movement direction of the underwater Rov 3.

  According to such a configuration, since it becomes easy to grasp the moving direction of the underwater Rov3, the position detecting unit 20 is moved so as to follow the underwater Rov3 more effectively, and the position of the underwater Rov3 is continuously detected. be able to.

  In the position detection system 1 according to the present embodiment, the position detection PC 6 corrects the relative position of the underwater Rov 3 in consideration of refraction of light in water.

  According to such a configuration, the relative position of the underwater Rov3 can be detected more accurately.

  Further, the position detection system 1 according to the present embodiment includes a depth sensor 31 that is mounted on the underwater Rov3 and detects the depth of the underwater Rov3. The position detection PC 6 detects distances in the X, Y, and Z directions between the position detection unit 20 and the underwater Rov3 based on the captured image of the underwater Rov3 (that is, the image of the light emitter 4). Then, the position detection PC 6 calculates the respective distances in the X and Y directions with the correction coefficient according to the error between the detected distance in the Z direction and the detected depth and the correction coefficient obtained from the correction of the bending with water. By correcting, the relative position of the underwater Rov3 is corrected.

  According to such a configuration, the detection result of the depth sensor 31 that is not affected by water refraction can be used as an accurate relative position in the Z direction of the underwater Rov3. In addition, the relative position of the underwater Rov 3 in the X and Y directions can be easily and appropriately corrected by a correction coefficient corresponding to the error between the detection depth and the Z position based on the captured image.

(Modification)
In addition to the configuration described above, various modifications can be applied to the position detection system 1. For example, FIG. 13 is a plan view showing a step of detecting the position of the underwater Rov 3 with respect to the origin in the position detection method according to the first modification of the present embodiment.

  In the example of FIG. 13, the position detection PC 6 has an underwater Rov3 in any coordinate area A among a plurality of coordinate areas A (that is, addresses) defined on the XY coordinate system along the liquid surface 10a. By detecting this, the position of the underwater Rov 3 with respect to the origin is detected.

  In the example of FIG. 13, on the XY coordinate system, a plurality of coordinate areas A are defined by a plurality of Y coordinates ag and a plurality of X coordinates 1-7.

In the example of FIG. 13, the position detection PC 6 detects the position of the underwater Rov3 with respect to the origin as a coordinate area A1 between the X coordinate: 6-7 and the Y coordinate: ef. In the example of FIG. 13, it is possible to roughly grasp the position of the water Rov3 as coordinate area.

  FIG. 14 is a block diagram showing a position detection system 1 according to a second modification of the present embodiment. FIG. 15 is a side view showing the position detection unit 20 in the position detection system 1 according to the second modification of the present embodiment. As a second modified example, as shown in FIGS. 14 and 15, the position detection unit 20 may further include a leveling device 29. In the illustrated example, the horizontality confirmation acceleration sensor 27 detects the shaking state of the position detection unit 20. The leveling device 29 adjusts at least one of the yaw angle and the pitch angle of the camera 23 based on the shaking state detected by the horizontality confirmation acceleration sensor 27 so that the imaging direction is downward. Here, when the underwater Rov 3 is imaged by the camera 23 of the position detection unit 20, the water surface 10 a undulates due to the water flow generated from the inner peripheral surface 9 a of the tank 9 as the underwater Rov 3 moves, etc. There is a possibility that the imaging direction may not be determined. However, according to the second modified example, since the imaging direction of the camera 23 can always be adjusted downward by the leveling device 29, the position of the underwater Rov3 can be appropriately detected without being affected by waves. Can do.

  FIG. 16 is a block diagram showing a position detection system 1 according to a third modification of the present embodiment. As a third modification, as shown in FIG. 16, the camera 23 may be equipped with a gimbal 231. The gimbal 231 adjusts the posture of the camera 23 so that the imaging direction of the camera 23 is downward. According to the third modification, the imaging direction of the camera 23 can always be adjusted downward by the gimbal 231. Therefore, as in the second modification, the position of the underwater Rov3 can be adjusted without being affected by waves. It can be detected properly.

  FIG. 17 is a flowchart showing a position detection method according to the fourth modification of the present embodiment. As a fourth modification, as shown in FIG. 17, the position detection CPU 22 calculates the inclination of the position detection unit 20 based on the detection result of the horizontality confirmation acceleration sensor 27 (step S <b> 61). The captured image of the light emitter 4 may be converted into a horizontal captured image based on the tilted inclination (step S62), and the relative position of the underwater Rov3 with respect to the position detection unit 20 may be calculated based on the converted captured image. (Step S63). According to the fourth modified example, by converting the captured image, the position of the underwater Rov 3 can be appropriately detected without being affected by the wave even if the mechanism for adjusting the posture of the camera 23 is not provided. Can do.

  FIG. 18 is a plan view showing a position detection system 1 according to a fifth modification of the present embodiment. FIG. 19 is a cross-sectional view taken along the line IX-IX in FIG. 18 showing a position detection system 1 according to a fifth modification of the present embodiment. FIG. 20 is a flowchart showing a position detection method 1 according to the fifth modification of the present embodiment. FIG. 21 is a plan view showing an angle determination step of the position detection unit 1 and a position calculation step based on the origin in the position detection method according to the fifth modification of the present embodiment.

  As shown in FIGS. 18 and 19, the position detection system 1 may further include a marker 100. The marker 100 is an object for determining the origin of the position detection unit 20 that is arranged in the tank 9 so that the laser light is irradiated from the laser unit 21. The marker 100 is not particularly limited as long as it can reflect the laser light emitted from the laser unit 21. For example, the marker 100 may be a hollow or solid metal body. As shown in FIG. 18, by making the marker 100 cylindrical, the position at which the marker 100 receives laser light can be reduced to one point. Therefore, the position detection unit 20 with the position of the marker 100 as the origin is used. Can be calculated with high accuracy.

  Further, as shown in FIGS. 18 and 19, the marker 100 may be thrown into the water while being suspended by the suspension device 92 through the tank manhole 91.

  The calculation of the position of the underwater Rov 3 by the position detection system 1 having such a configuration may be performed in accordance with the flowchart of FIG. Specifically, first, the marker 100 is put into the water while the marker 100 is suspended from the tank manhole 91 into the tank 9 by the suspension device 92. That is, the marker 100 is disposed in the tank 9 so that the laser light is emitted from the laser unit 21.

  Then, at the central position of the tank 9, the laser unit 21 irradiates the inner peripheral surface 9a of the tank 9 with the laser light L along the circumferential direction while rotating 360 °. At this time, the laser beam L is also irradiated to the marker 100. The laser unit 21 receives the laser light L applied to the inner peripheral surface 9a and the marker 100, and from the position detection unit 20 to the inner peripheral surface 9a or the marker 100 based on the time from irradiation to reception of the laser light L. Measure distance. And the laser unit 21 acquires the point cloud data which show the measurement result of distance, as shown in FIG. At this time, the point cloud data of the marker 100 is acquired as point cloud data protruding inward from the inner peripheral surface 9a (step S101).

  After acquiring the point group data of the marker 100, the position detection CPU 22 determines the position of the marker 100 indicated by the point group data as the origin (0, 0) of the position detection unit 20, as shown in FIG. (Step S31). In the example of FIG. 21, the coordinates of the center of the tank 9 are (r1, 0) with the origin (0, 0) as a reference.

  After the position of the marker 100 is determined to be the origin (0, 0) of the position detection unit 20, as shown in FIG. 20, the position detection CPU 22 is a straight line connecting the center position of the tank 9 and the origin (0, 0). The angle of the position detection unit 20 with reference to 101 (see FIG. 21) is determined (step S12). In the example of FIG. 21, the angle of the position detection unit 20 after being moved from the center position of the tank 9 by the moving thruster 24 is represented by the symbol θ.

  After determining the angle of the position detection unit 20, the position detection CPU 22 determines the origin (0, 0, 0) based on the determined angle of the position detection unit 20 and the distance from the origin (0, 0) to the position detection unit 20. 0) is calculated as a reference (step S51). In the example of FIG. 21, the distance from the origin (0, 0) to the position detection unit 20 after moving from the center position of the tank 9 by the moving thruster 24 is represented by the symbol r2. In this case, the position of the position detection unit 20 with respect to the origin (0, 0) is determined using the distance r2 from the origin (0, 0) to the position detection unit 20 and the angle θ of the position detection unit 20 ( r2cosθ, r2sinθ2).

  After calculating the position of the position detection unit 20 with the origin (0,0) as a reference, the processing after step S6 is executed as in FIG.

  That is, according to the fifth modification, the position detection system 1 further includes a marker 100 disposed in the tank 9 so that the laser light is emitted from the laser unit 21. The position detection CPU 22 determines the position of the marker 100 as the origin (0, 0) of the position detection unit 20 based on the point cloud data of the laser light emitted from the laser unit 21 to the marker 100 at the central position of the tank 9. To do. Further, the position detection CPU 22 determines the angle θ of the position detection unit 20 with reference to the line 101 connecting the center position of the tank 9 and the origin (0, 0) after the position detection unit 20 is moved by the movement thruster 24. decide. Further, the position detection CPU 22 determines the position of the position detection unit 20 based on the origin (0, 0) based on the determined angle θ and the distance from the origin (0, 0) to the position detection unit 20. To detect. Further, the position detection CPU 22 detects the relative position of the underwater Rov3 with respect to the position detection unit 20 based on the captured image, and the position of the position detection unit 20 with respect to the origin (0, 0) is relative to the underwater Rov3. By combining the position and the position, the position of the underwater Rov 3 with respect to the origin (0, 0) is detected.

  According to the fifth modification, the position accuracy of the underwater Rov3 can be improved by detecting the position of the underwater Rov3 with the position of the marker 100 as a reference.

  FIG. 22 is a plan view showing the measured distance D between the light emitters 4 in the position detection method according to the sixth modification of the present embodiment. FIG. 23 is a side view showing distances X1 and X2 from the position detection unit 20 to the underwater Rov3 in the position detection method according to the sixth modification of the present embodiment. FIG. 24 is a plan view showing distances d1 and d2 between the light emitters 4 on the captured image in the position detection method according to the sixth modification of the present embodiment.

  The position detection CPU 22 sets the ratios d1 / D and d2 / D between the distances d1 and d2 between the light emitters 4 on the captured image shown in FIG. 24 and the measured distance D between the light emitters 4 shown in FIG. Based on this, the distance per unit pixel between the position detection unit 20 and the underwater Rov3 may be calculated. Note that the distance d1 between the light emitters 4 in FIG. 24 is the distance between the light emitters 4 on the captured image captured at the position P1 in FIG. The distance d2 between the light emitters 4 in FIG. 24 is the distance (<d1) between the light emitters 4 on the captured image captured at the position P2 in FIG. 23 deeper than the position P1. Then, based on the calculated distance per unit pixel and the number of pixels between the position detection unit 20 and the underwater Rov3, the position detection CPU 22 receives the underwater detection from the position detection unit 20 as shown in FIG. The distances X1 and X2 to Rov3 may be calculated. A distance X1 in FIG. 23 is a distance from the position detection unit 20 to the underwater Rov3 at the position P1. A distance X2 in FIG. 23 is a distance from the position detection unit 20 to the underwater Rov3 at the position P2. Then, the position detection CPU 22 may detect the relative position of the underwater Rov3 based on the calculated distance from the position detection unit 20 to the underwater Rov3.

  According to the sixth modification, the relative position of the underwater Rov3 is determined based on the ratios d1 / D and d2 / D between the distances d1 and d2 between the light emitters 4 and the measured distance D between the light emitters 4 on the captured image. Based on the detected relative position, the position of the underwater Rov 3 can be detected based on the origin (0, 0). Thereby, since the correction of the relative position of the underwater Rov3 using the depth sensor 31 and the depth sensor 31 can be omitted, the number of parts can be reduced and the position detection of the underwater Rov3 can be simplified. .

  As another modified example, the movement thruster 24 is configured to avoid an underwater interference object based on a captured image of the camera 23 when the position detection unit 20 follows the movement of the underwater Rov3. 20 may be moved.

  As another modification, the sensitivity of the camera 23 may be adjusted according to the transparency of the water so that the underwater Rov3 can be appropriately imaged even when the transparency of the water is low.

  As another modification, a weight may be mounted on the camera 23 so that the imaging direction of the camera 23 is always adjusted downward.

  In addition, the position detection system 1 can be applied to detect the position of the underwater Rov 3 inside a tank having a shape other than a circle such as a rectangle.

  At least a part of the position detection system 1 according to the present embodiment may be configured by hardware or software. When configured by software, a program for realizing at least a part of the functions of the position detection system 1 may be stored in a recording medium such as a flexible disk or a CD-ROM, and read and executed by a computer. The recording medium is not limited to a removable medium such as a magnetic disk or an optical disk, but may be a fixed recording medium such as a hard disk device or a memory. Further, a program that realizes at least a part of functions of the semiconductor inspection system may be distributed via a communication line (including wireless communication) such as the Internet. Further, the program may be distributed in a state where the program is encrypted, modulated or compressed, and stored in a recording medium via a wired line such as the Internet or a wireless line.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 Position detection system 2 Position detection apparatus 21 Laser unit 22 CPU for position detection
6 PC for position detection

Claims (18)

A position detection device that floats on the liquid stored in the tank and detects the position of the target object in the liquid;
The position detection device includes:
A laser beam is applied to the inner peripheral surface of the tank while rotating about a rotation axis in a direction intersecting the liquid surface of the liquid, and the distance to the inner peripheral surface is received by receiving the irradiated laser light. A laser measuring device for acquiring point cloud data indicating a measurement result;
A position detection unit that determines a specific position in an area surrounded by the acquired point cloud data as an origin of the position detection device, and detects a position of the target object with reference to the determined origin; A position detection system. The target object is a movable body that is movable in the liquid,
The position detection device includes:
An imaging device that images the target object at a predetermined viewing angle;
A moving device that moves the position detecting device on the liquid surface so that the target object is captured within the viewing angle;
The position detection system according to claim 1, wherein the position detection unit detects a position of the target object based on the origin based on a captured image obtained by capturing the target object. The position detector is
The position detection based on the origin by comparing the position of the position detection device in the region surrounded by the point cloud data acquired by the laser measurement device after the movement by the movement device with the origin. Detect the position of the device,
Detecting a relative position of the target object with respect to the position detection device based on the captured image;
The position of the target object with respect to the origin is detected by combining the position of the position detection device with the detected origin as a reference and the relative position of the detected target object. The position detection system described in. The position detector is
The position detection system according to claim 3, wherein the relative position of the target object is corrected in consideration of light refraction in the liquid. A depth meter mounted on the target object for detecting the depth of the target object in the liquid;
The position detector is
Based on the captured image, the respective distances in the X and Y directions along the liquid surface and the Z direction intersecting the liquid surface between the position detection device and the target object are detected and detected. 5. The relative position of the target object is corrected by correcting the detected distance in the X and Y directions with a correction coefficient corresponding to an error between a distance in the Z direction and the detected depth. Position detection system. Further comprising at least one light emitter mounted on the target object and flashing;
The position detection system according to any one of claims 3 to 5, wherein the position detection unit detects a relative position of the target object based on an image of the light emitter in the captured image. Comprising three or more of the light emitters,
The position detection system according to claim 6, wherein the three or more light emitters are arranged to indicate a moving direction of the target object. The position detector is
The position of the target object with reference to the origin by detecting in which coordinate area of the plurality of coordinate areas defined on the XY coordinate system along the liquid surface the target object exists The position detection system of any one of Claims 1-7 which detects.   The position detection system according to any one of claims 1 to 8, further comprising a display device that displays the detected position of the target object as an image and a numerical value on an XY coordinate system along the liquid surface.   The position detection system according to claim 1, wherein the tank is made of metal. The tank is made of metal,
The position detection system according to claim 5, wherein the depth meter is a pressure type.   The position detection system according to claim 1, wherein the target object is a remote control type unmanned submersible. The position detection device further includes:
An acceleration sensor for detecting a shaking state of the position detecting device;
A leveling device that adjusts at least one of a yaw angle and a pitch angle of the imaging device based on the detected shaking state so that an imaging direction is a downward direction. The position detection system according to item.   The position detection system according to claim 2, wherein the imaging device includes a gimbal that adjusts an attitude of the imaging device so that an imaging direction is a downward direction. The position detection device further includes:
An acceleration sensor for detecting the inclination of the position detection device;
The position detector is
The captured image is converted into a horizontal captured image based on the detected inclination, and the relative position of the target object with respect to the position detection device is detected based on the converted captured image. Position detection system. A marker disposed in the tank so that the laser beam is emitted from the laser measuring device;
The position detector is
Based on the point cloud data of the laser beam irradiated to the marker from the laser measurement device at a predetermined position in the tank, the position of the marker as the specific position is determined as the origin of the position detection device,
After movement by the moving device, determine an angle of the position detecting device with reference to a line connecting the predetermined position and the determined origin,
Based on the determined angle and the distance from the origin to the position detection device, the position of the position detection device relative to the origin is detected,
Detecting a relative position of the target object with respect to the position detection device based on the captured image;
The position of the target object with respect to the origin is detected by combining the position of the position detection device with the detected origin as a reference and the relative position of the detected target object. The position detection system described in. The position detector is
Based on the ratio between the distance between the light emitters on the captured image and the measured distance between the light emitters, a distance per unit pixel between the position detection device and the target object is calculated,
Based on the calculated distance per unit pixel and the number of pixels between the position detection device and the target object, calculate the distance from the position detection device to the target object,
The position detection system according to claim 6 or 7, wherein a relative position of the target object is detected based on the calculated distance from the position detection device to the target object. A position detector equipped with a laser measuring device is suspended in the liquid stored in the tank,
While rotating the laser measuring device around a rotation axis in a direction intersecting the liquid level of the liquid, the laser measuring device irradiates the inner peripheral surface of the tank with laser light, and the irradiated laser light is By receiving light with a laser measuring device, obtain point cloud data indicating the measurement result of the distance to the inner peripheral surface,
Determining the specific position of the area surrounded by the acquired point cloud data as the origin of the position detecting device detects the position of the target object in said liquid with respect to the said determined origin position Detection method.