Search system and search method for unmanned underwater vehicles

Abstract

To provide a search system and a search method for an unmanned underwater vehicle capable of easily identifying the location of an unmanned underwater vehicle.SOLUTION: A search system 1 comprises an unmanned aircraft 10, an imaging apparatus 30 installed on the unmanned aircraft 10, and a control part 18, where the control part calculates an estimated arrival point 4 of an unmanned underwater vehicle 3 and the maximum value of a position error with respect to the estimated arrival point 4 based on waypoint data of the unmanned underwater vehicle 3, sets such photographable positions to the unmanned aircraft 10 on condition that a search area 5 which has the estimated arrival point 4 as the center and has the maximum value of the position error as the radius is in the photographable positions by the imaging apparatus 30, detects the unmanned underwater vehicle 3 from the image acquired by photographing the search area 5 with the imaging apparatus 30, and gives notification of the detection of the unmanned underwater vehicle 3.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present disclosure relates to a search system and a search method for an unmanned underwater vehicle. [Background technology]

[0002] Unmanned vehicles that navigate on or underwater are called unmanned underwater vehicles (UUVs) and are used for the purposes of exploration, investigation, surveying, photography, etc. Unmanned underwater vehicles are further classified into autonomous underwater vehicles (AUVs) and remotely operated unmanned underwater vehicles (ROVs). For the sake of convenience, unmanned underwater vehicles will be referred to as UUVs below.

[0003] Patent Document 1 discloses an underwater exploration system in which an underwater exploration unit equipped with a UUV and a means for transmitting position information of the UUV is recovered by an unmanned aerial vehicle operated based on the position information. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2017 / 094635 Summary of the Invention [Problem to be solved by the invention]

[0005] When a mother ship retrieves a UUV, it is necessary to avoid an unexpected collision between the mother ship and the UUV. Therefore, the UUV slows down or stops at a distance of tens to hundreds of meters from the mother ship. In other words, to start the retrieval operation, the retrieval worker needs to confirm the position of the UUV at a distance of tens to hundreds of meters from the UUV. While this position confirmation is performed visually, a decelerated or stopped UUV is easily swept away by the influence of wind, waves, or water currents, making the search difficult.

[0006] If the UUV has the ability to communicate with the mother ship, the UUV's position can be determined through radio communication with the mother ship. However, radio communication may not be possible due to malfunctions in the communications equipment, communication interruptions due to bad weather, or characteristics of the communications standard (for example, the presence of shadow zones in acoustic communications). In addition, the final destination, or recovery location, can be determined from waypoint data entered into the UUV. However, since positioning using inertial navigation involves a certain degree of error, the UUV may appear from an unexpected location. In any case, visual confirmation of the location is ultimately required, which can make the search difficult.

[0007] The present disclosure has been made in consideration of the above circumstances, and aims to provide a search system and search method for an unmanned underwater vehicle that can easily identify the position of the unmanned underwater vehicle. [Means for solving the problem]

[0008] A search system according to one aspect of the present disclosure includes an unmanned aerial vehicle, a photographing device provided on the unmanned aerial vehicle, and a control unit that calculates a planned arrival point of the unmanned underwater vehicle and a maximum value of a position error for the planned arrival point based on waypoint data of the unmanned underwater vehicle, sets a position in the unmanned aerial vehicle where a search area centered on the planned arrival point and having a radius of the maximum value of the position error can be photographed by the photographing device, detects the unmanned underwater vehicle from an image obtained by photographing the search area by the photographing device, and notifies the detection of the unmanned underwater vehicle. The notification of the detection by the control unit includes controlling flight operations of the unmanned aerial vehicle indicative of the detection.

[0009] The control unit may control a movement of the unmanned aerial vehicle so as to maintain the unmanned underwater vehicle within an angle of view of the image capturing device after the unmanned underwater vehicle is detected. The notification of the detection by the control unit may include transmitting a signal indicative of the detection. . beforeThe unmanned aerial vehicle may be equipped with a lighting device, and the notification of the detection by the control unit may include control of the lighting device to turn on the lighting device to indicate the detection. The control unit may transmit position information of the unmanned underwater vehicle together with the notification of the detection of the unmanned underwater vehicle. The control unit may be mounted on the unmanned aerial vehicle. The control unit may be provided as a remote control device for the unmanned aerial vehicle.

[0010] A method for searching for an unmanned underwater vehicle according to one aspect of the present disclosure includes moving an unmanned aerial vehicle toward a search area having a center at a planned arrival point of the unmanned underwater vehicle and a radius of a maximum value of a position error relative to the planned arrival point, based on waypoint data of the unmanned underwater vehicle, photographing the search area using a photographing device provided on the unmanned aerial vehicle, detecting the unmanned underwater vehicle from an image acquired by the photographing, and notifying the detection of the unmanned underwater vehicle. and wherein the notification of the detection includes flight behavior of the unmanned aerial vehicle indicative of the detection. .

[0011] After the unmanned underwater vehicle is detected, the unmanned aerial vehicle may be moved so as to maintain the unmanned underwater vehicle within a field of view of the image capture device. The notification of the detection may include transmitting a signal indicative of the detection. . before The notification of the detection may include an optical notification indicative of the detection. Position information of the unmanned underwater vehicle may be transmitted in conjunction with the notification of the detection of the unmanned underwater vehicle. Effect of the Invention

[0012] According to the present disclosure, it is possible to provide a search system and a search method for an unmanned underwater vehicle that can easily identify the position of the unmanned underwater vehicle. [Brief description of the drawings]

[0013] [Figure 1] 1 is a diagram showing an overview of a method for searching for an unmanned underwater vehicle according to an embodiment of the present disclosure. [Diagram 2] 1 is a functional block diagram showing an example of a search system according to an embodiment of the present invention. [Diagram 3]A side view showing an example of the configuration of an unmanned aerial vehicle according to this embodiment. [Figure 4] 10 is a flowchart showing an example of the operation of the search system according to the present embodiment. [Diagram 5] FIG. 13 is a diagram for explaining setting of a search area according to the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, some embodiments of the present disclosure will be described with reference to the accompanying drawings. In addition, common parts in each drawing are given the same reference numerals, and duplicated description will be omitted. The search target of the search method according to this embodiment is an unmanned underwater vehicle (UUV). For convenience of explanation, the unmanned underwater vehicle will be referred to as a UUV below. The UUV 3 according to this embodiment may be an autonomous unmanned underwater vehicle (AUV) or a remotely operated unmanned underwater vehicle (ROV). The UUV 3 is launched underwater (for example, under the sea) from a mother ship 2 or the like, and performs activities such as exploration, investigation, surveying, and photography.

[0015] Fig. 1 is a diagram showing an overview of a search method for a UUV 3 according to this embodiment. As shown in this figure, the UUV 3 moves toward a planned arrival point (final arrival point) 4 to be recovered, and stops within a search area 5 including the planned arrival point 4. For example, as shown in Fig. 1, the UUV 3 moves underwater and surfaces within the search area 5.

[0016] Meanwhile, the unmanned aerial vehicle 10 flies from a mother ship 2 toward a search area 5 by automatic operation or by remote control from a mother ship (remote control device) 2. After arriving in the sky above the search area 5, the unmanned aerial vehicle 10 stops in the air and starts photographing the search area 5. An image of the search area 5 is obtained by this photographing.

[0017] Next, a predetermined image processing is performed on the acquired image to determine whether or not a UUV 3 is present. If a UUV 3 is detected by this image processing, the unmanned aerial vehicle 10 notifies the mother ship 2 of the discovery of the UUV 3. When making this notification, the position information of the UUV 3 is transmitted from the unmanned aerial vehicle 10 to the UUV 3. At this time, the position information may not be transmitted and the UUV 3 may remain stationary above the unmanned aerial vehicle 10. Upon receiving the notification, the mother ship 2 approaches the UUV 3 that has stopped in the search area 5 based on the position information of the UUV 3 or using the unmanned aerial vehicle 10 as a landmark. The mother ship 2 then recovers the UUV 3 using a lift (not shown) or the like mounted on the mother ship 2.

[0018] The base from which the unmanned aerial vehicle 10 takes off and lands is not limited to a ship equipped with self-propelled equipment. The base of the unmanned aerial vehicle 10 may be a barge or the like not equipped with self-propelled equipment, or may be a port facility such as a quay. When recovering the UUV 3, a work boat (not shown) heads to the recovery location.

[0019] A search system 1 according to this embodiment will be described. Fig. 2 is a functional block diagram showing an example of the configuration of the search system 1. Fig. 3 is a side view showing an example of the configuration of the unmanned aerial vehicle 10. As shown in Fig. 2, the search system 1 includes the unmanned aerial vehicle 10 and an imaging device 30 provided on the unmanned aerial vehicle 10.

[0020] The unmanned aerial vehicle 10 is a flying object capable of stationary in the air (i.e., capable of hovering), such as a rotorcraft. The unmanned aerial vehicle 10 flies toward a search area 5 for the UUV 3. The search area 5 is obtained from waypoint data for the UUV 3. An example in which a rotorcraft is used as the unmanned aerial vehicle 10 will be described below.

[0021] 2 and 3, unmanned aerial vehicle 10 includes rotor 11, motor 12, motor drive unit 13, positioning unit 14, sensor unit 15, communication unit 16, input / output unit (I / O) 17, and control unit 18. Unmanned aerial vehicle 10 may further include a lighting device 19 such as a flasher.

[0022] The motor 12 is mounted, for example, on the fuselage 20 of the unmanned aerial vehicle 10 or on an arm 20a extending from the fuselage 20. The rotor 11 is attached to the output shaft of the motor 12 and generates lift by rotating together with the output shaft. The motor drive unit 13 is a drive circuit for the motor 12 and supplies the motor 12 with the power required to rotate the output shaft. The rotation speed of the output shaft is controlled by a control unit 18.

[0023] The positioning unit 14 includes a satellite navigation system such as the Global Positioning System or the Quasi-Zenith Satellite System, and measures the horizontal position (latitude and longitude). The positioning unit 14 also includes an altimeter (not shown), and measures the vertical position (i.e., altitude). The measurement results by the positioning unit 14 are input to the control unit 18.

[0024] The sensor unit 15 includes sensors necessary for flight control of the unmanned aerial vehicle 10. The sensor unit 15 is composed of at least an acceleration sensor and a gyro sensor, which are used for attitude control and orientation control of the unmanned aerial vehicle 10. The sensor unit 15 may include any sensor, such as an acoustic sensor, a temperature sensor, or an air pressure sensor, depending on the usage environment. The positioning unit 14 and the sensor unit 15 function as an inertial navigation system for performing inertial navigation of the unmanned aerial vehicle 10.

[0025] The communication unit 16 communicates with the mother ship 2 via a network established between the mother ship 2. This communication may be either wireless or wired communication. For example, wireless communication may be performed using microwaves in the 2.4 GHz band used in wireless LANs (Local Area Networks). The input / output unit (I / O) 17 is a general-purpose input / output port for data, control signals, power, etc., and is connected to electronic devices such as the imaging device 30 described below.

[0026] The photographing device 30 is composed of a well-known photographing means such as a CCD (Charge Coupled Device) camera, and is attached to the bottom surface 20b of the fuselage 20, for example, as shown in FIG. 3. The photographing device 30 photographs the water surface directly below the unmanned aerial vehicle 10 in the vertical direction, and sends the image data to the control unit 18 via the input / output unit (I / O) 17. The photographing device 30 has a predetermined angle of view α. This angle of view α is stored in advance in an auxiliary storage device of the control unit 18. The photographing device 30 may be attached to the fuselage 20, etc., as a separate unit from the unmanned aerial vehicle 10, or may be built into the unmanned aerial vehicle 10 as an auxiliary device of the unmanned aerial vehicle 10.

[0027] The control unit 18 is composed of a central processing unit (CPU), a memory, an auxiliary storage device, etc., and functions as a control unit of the search system 1. The control unit 18 executes various processes such as flight control based on programs and data stored in the memory or the auxiliary storage device, and controls the operations of the motor drive unit 13, the positioning unit 14, the communication unit 16, the input / output unit (I / O) 17, the imaging device 30, etc. For example, the control unit 18 controls the motor drive unit 13 based on commands received from the mother ship 2 via the communication unit 16, and executes the movement and stationary movement of the unmanned aerial vehicle 10 in the air. The control unit 18 also executes a series of processes for searching for the UUV 3. These processes include, for example, setting the imaging position and image processing (described later).

[0028] The following describes the operation of the search system 1. Fig. 4 is a flowchart showing an example of the operation of the search system 1. Fig. 5 is a diagram for explaining the setting of a search area 5.

[0029] In the inertial navigation used by UUV3, positioning errors cause position errors with respect to the waypoint (arrival point). The position error is the deviation (distance) between the planned arrival point 4 and the location where UUV3 may actually appear (arrive). The position error increases according to the cruising distance unless coordinate calibration is performed using GPS or the like. Therefore, UUV3 may appear at a location that is the position error away from the planned arrival point 4, which is the recovery location.

[0030] As described above, when the mother ship etc. recovers the UUV 3, the position of the UUV 3 is confirmed at a location several tens to several hundreds of meters away from the mother ship etc. However, due to position errors accumulated during navigation, the UUV 3 does not necessarily appear at the planned arrival point 4.

[0031] Therefore, the control unit 18 according to this embodiment identifies the planned arrival point 4 from the waypoint data of the UUV 3 (step S10). The waypoint data of the UUV 3 is pre-stored in the control unit 18 of the unmanned aerial vehicle 10. Furthermore, the control unit 18 calculates the maximum value of the position error from this waypoint data, taking into account the cruising distance (step S11). The calculated position error is a standard error based on an empirically obtained standard deviation, for example. Note that the standard error may be multiplied by a weighting factor that takes into account the natural environment into which the UUV 3 is deployed, i.e., water currents, ocean currents, and surface currents and waves according to wind speed. In this case as well, the control unit 18 calculates the maximum value of the position error.

[0032] A search area 5 is defined from the identified planned arrival point 4 and the calculated maximum value of the position error. The search area 5 is a set of positions where the UUV 3 is highly likely to eventually appear (arrive), and is defined as a circular area with the planned arrival point 4 at its center and the maximum value of the position error relative to the planned arrival point 4 as its radius.

[0033] The control unit 18 stores the angle of view α of the image capture device 30. The control unit 18 calculates the altitude A of the unmanned aerial vehicle 10 so that the entire search area 5 falls within this angle of view α, and sets a position (hereinafter referred to as the image capture position) 6 from which the entire search area 5 can be captured (step S12). For example, as shown in Fig. 5, when the image capture device 30 captures the planned arrival point 4 from directly above, in other words, when the planned arrival point 4 is located on the optical axis 7 of the image capture device 30 that extends vertically, the angle of view α and the maximum value r of the position error max The altitude A for is given by the following formula: A=r max / tan(α / 2). Note that the photographing position 6 is not limited to a position directly above the planned arrival point 4, so long as it is in the vicinity of the search area 5 where the unmanned aerial vehicle 10 can be photographed (detected).

[0034] Next, control unit 18 controls motor drive unit 13 and the like to move unmanned aerial vehicle 10 to photographing position 6 (step S13). After that, photographing device 30 starts photographing the entire search area 5 (step S14). The obtained images are sent to control unit 18.

[0035] The surfaced UUV 3 is stopped in the search area 5. Therefore, the UUV 3 should be captured in the image acquired by the imaging device 30. The control unit 18 detects the UUV 3 from this image. Specifically, a predetermined image processing is performed on the image to detect the UUV 3 (step S15). The predetermined image processing is, for example, well-known image processing such as color identification (color tracking) based on the paint color of the UUV 3, template matching based on the shape of the UUV 3, or contour extraction of the UUV 3 by edge processing.

[0036] Next, the control unit 18 judges whether or not a UUV 3 is detected from the image (step S16). If a UUV 3 is not detected from the image (NO in step S16), the photographing in step S14 and the image processing in step S15 are repeated. On the other hand, if a UUV 3 is detected from the image (NO in step S16), the control unit 18 notifies the detection of a UUV 3 (step S17).

[0037] The notification of detection of the UUV 3 (hereinafter referred to as detection notification) is, for example, the transmission of a signal indicating the detection of the UUV 3 from the control unit 18 to the mother ship 2. The mother ship 2 receives this notification and confirms the position of the unmanned aerial vehicle 10 (for example, visually).

[0038] After detecting UUV3, if UUV3 remains in a stopped position (NO in step S18), the mother ship 2 approaches UUV3 using the position of the unmanned aerial vehicle 10 as a guide. When the mother ship 2 approaches UUV3 close enough to begin recovery operations, the mother ship 2 transmits a signal to the unmanned aerial vehicle 10 indicating the end of the search for UUV3, and the search ends (YES in step S20). The mother ship 2 then begins recovery operations for UUV3. The detection notification continues until a signal indicating the end of the search is transmitted (NO in step S20). However, if there is no concern that UUV3 will move, the detection notification may be omitted.

[0039] After detecting UUV3, if UUV3 moves from the stopped position due to water currents (ocean currents), waves, etc. (YES in step S18), the control unit 18 moves the unmanned aerial vehicle 10 so that UUV3 remains positioned within the angle of view α of the imaging device 30 (step S19). That is, the unmanned aerial vehicle 10 tracks UUV3. Tracking by the unmanned aerial vehicle 10 continues until the unmanned aerial vehicle 10 transmits a signal indicating the end of the search for UUV3 (NO in step S20). However, during tracking, the detection notification may continue or may end. Which of these is selected is determined by taking into consideration, for example, the size of the search area 5 (i.e., the ease of finding UUV3), etc.

[0040] While the unmanned aerial vehicle 10 is tracking the UUV 3, the mother ship 2 approaches the UUV 3. Then, when the mother ship 2 approaches the UUV 3 close enough to start recovery operations, the mother ship 2 transmits a signal to the unmanned aerial vehicle 10 indicating the end of the search for the UUV 3, and the search ends (YES in step S20). The mother ship 2 then starts recovery operations for the UUV 3.

[0041] The control unit 18 may transmit the position information of the UUV 3 together with the notification of the detection of the UUV 3. The unmanned aerial vehicle 10 knows its own position from the information obtained from the positioning unit 14. Therefore, the control unit 18 can calculate the relative position of the UUV 3 with respect to the unmanned aerial vehicle 10 (camera device 30), thereby identifying the position of the UUV 3. Since the mother ship 2 obtains the position information of the UUV 3, it can approach the UUV 3 without considering the position or recognition of the UUV 3.

[0042] The detection notification of UUV3 may include a flight operation of the unmanned aerial vehicle 10 indicating the detection of UUV3. This flight operation is, for example, a round trip flight or a circular flight of UUV3 along a predetermined direction, and is executed by the flight control of the control unit 18. UUV3 is hovering for photographing. Therefore, by executing a flight operation different from the flight operation during hovering, the operator of the unmanned aerial vehicle 10 can be made aware of the discovery of UUV3.

[0043] The UUV 3 detection notification may include an optical notification indicating the detection of the UUV 3. That is, if the unmanned aerial vehicle 10 is equipped with a light 19, the light 19 may be controlled by the control unit 18 to perform an operation such as blinking to indicate the detection.

[0044] Neither the flight motion nor the optical notification indicating detection of the UUV 3 requires communication between the mother ship 2 and the unmanned aerial vehicle 10. Thus, even if communication between the mother ship 2 and the unmanned aerial vehicle 10 is interrupted due to an unforeseen event, the mother ship 2 can rely on the position of the unmanned aerial vehicle 10 to approach and recover the UUV 3.

[0045] The processing from steps S10 to S20 may be executed by a remote control device (see FIG. 1) of the unmanned aerial vehicle 10 operated within the mother ship 2 as the control unit of the search system 1. The remote control device is a so-called computer composed of a central processing unit (CPU), memory, auxiliary storage device, display device, and input devices such as a keyboard, and has the function of communicating with the communication unit 16 of the unmanned aerial vehicle 10. In this case, the remote control device performs the calculation processing of the processing from steps S10 to S20, and the control unit 18 of the unmanned aerial vehicle 10 mainly performs flight control and lighting control of the unmanned aerial vehicle 10 based on commands from the remote control device.

[0046] In this embodiment, a search area is set based on the waypoint data of the UUV 3, and the unmanned aerial vehicle 10 photographs an area including the search area to detect the UUV 3. The search area is a circular area with the planned arrival point as the center and the maximum value of the position error for the planned arrival point as the radius. Since the possibility of the UUV 3 appearing in an area other than the search area is statistically low, the search for the UUV 3 may be performed within the search area. In other words, the position of the UUV 3 can be easily identified. In addition, the position of the UUV 3 can be identified without confirming the position of the UUV 3 through communication between the UUV 3 and the mother ship 2. Therefore, even in a configuration in which the position is confirmed through communication between the UUV 3 and the mother ship 2, the introduction of the search system of this embodiment allows the position of the UUV 3 to be identified even in a state in which communication is not working properly.

[0047] The present disclosure is not limited to the above-described embodiment, but is defined by the claims, and includes all modifications within the meaning and scope equivalent to the claims. [Explanation of symbols]

[0048] 1...search system, 2...mother ship, 3...UUV (unmanned underwater vehicle), 4...planned arrival point, 5...search area, 6...shooting position, 7...optical axis, 10...unmanned aerial vehicle, 11...rotor, 12...motor, 13...motor drive unit, 14...positioning unit, 15...sensor unit, 16...communication unit, 17...input / output unit (I / O), 18...control unit, 19...lighting device, 20...fuselage, 20a...arm, 20b...bottom, 30...shooting device

Claims

1. Unmanned aerial vehicles and An imaging device provided on the unmanned aerial vehicle; Calculating a planned arrival point of the unmanned underwater vehicle and a maximum value of a position error relative to the planned arrival point based on waypoint data of the unmanned underwater vehicle; A search area having a center at the scheduled arrival point and a radius of the maximum value of the position error is set in the unmanned aerial vehicle at a position where the image capturing device can capture the image; Detecting the unmanned underwater vehicle from an image acquired by photographing the search area with the photographing device; A control unit that notifies detection of the unmanned underwater vehicle; Equipped with The notification of the detection by the controller includes controlling a flight operation of the unmanned aerial vehicle indicative of the detection. Search system.

2. The control unit controls the movement of the unmanned aerial vehicle so that the unmanned underwater vehicle is maintained within the angle of view of the imaging device after the unmanned underwater vehicle is detected. The search system according to claim 1 .

3. The notification of the detection by the control unit includes transmitting a signal indicative of the detection. The search system according to claim 1 or 2.

4. The unmanned aerial vehicle is equipped with a light; The notification of the detection by the control unit includes a lighting control for the lighting device indicating the detection. The search system according to claim 1 or 2.

5. The control unit transmits position information of the unmanned underwater vehicle together with the notification of the detection of the unmanned underwater vehicle. A search system according to any one of claims 1 to 4.

6. The control unit is mounted on the unmanned aerial vehicle. A search system according to any one of claims 1 to 5.

7. The control unit is provided as a remote control device for the unmanned aerial vehicle. A search system according to any one of claims 1 to 5.

8. Based on the waypoint data of the unmanned underwater vehicle, the unmanned aerial vehicle is moved to a position where a search area having a center at a planned arrival point of the unmanned underwater vehicle and a radius of a maximum value of a position error with respect to the planned arrival point can be photographed; Photographing the search area using a photographing device provided on the unmanned aerial vehicle; Detecting the unmanned underwater vehicle from the image acquired by the photographing; notifying detection of the unmanned underwater vehicle; The notification of the detection includes flight behavior of the unmanned aerial vehicle indicative of the detection. A method for searching for an unmanned underwater vehicle.

9. After the unmanned underwater vehicle is detected, the unmanned aerial vehicle is moved so as to maintain the unmanned underwater vehicle within the angle of view of the imaging device. The searching method according to claim 8.

10. The notification of the detection includes transmitting a signal indicative of the detection. The searching method according to claim 8 or 9.

11. The indication of the detection includes an optical indication of the detection. The searching method according to claim 8 or 9.

12. Transmitting location information of the unmanned underwater vehicle together with the notification of the detection of the unmanned underwater vehicle. A searching method according to any one of claims 8 to 11.

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