Underwater diving system

Abstract

To provide an underwater diving system capable of grasping the position of a diving machine without being affected by a multi-pass.SOLUTION: An underwater diving system 1 comprises a diving machine 10 with a propeller 15 to generate a propulsion force in a propulsion direction, a measuring machine 20 to measure the water flow velocity received by the diving machine 10 in the propulsion direction, and a control terminal 30 having a calculation part to calculate the moving distance of the diving machine 10 and having a storage part to store first flow velocity information in advance. The first flow velocity information indicates the flow velocity relation relative to the output of the propeller 15 measured by the measuring machine 20 when the diving machine 10 is propelled in the propulsion direction from the condition where there is no water flow around the diving machine 10. The calculation part calculates the moving distance of the diving machine 10 by correcting the reference moving distance calculated from the output of the propeller 15 and the operation time of the propeller 15 based on the actual value of the flow velocity measured by the measuring machine 20 and on the reference flow velocity corresponding to the prescribed output in the first flow velocity information when the propeller 15 is operated at the prescribed output.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an underwater submersible system. [Background technology]

[0002] Patent Document 1 discloses an underwater exploration robot equipped with a propulsion unit, a camera, and the like. The underwater exploration robot is used to inspect objects such as dam walls. In an inspection using the underwater exploration robot, the propulsion unit is used to submerge close to the object to be inspected, and the underwater exploration robot is then moved along the object to photograph the object with a camera. The presence or absence of cracks in the object to be inspected is then inspected from the captured video or still images. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-178411 A Summary of the Invention [Problem to be solved by the invention]

[0004] Conventionally, in inspections using underwater exploration robots, devices such as sonar and transponders have been used to detect the position of the underwater exploration robot. When using such devices in places surrounded by steel materials such as dam walls or steel pipe piles, or in closed places with shallow water depth, it is difficult to grasp the exact position due to the strong influence of multipath. [Means for solving the problem]

[0005] An underwater diving system that solves the above-mentioned problem comprises a submersible having a propulsion unit that generates propulsion in a propulsion direction, a measuring unit that measures the flow speed of the water current that the submersible experiences in the propulsion direction relative to the submersible, a calculation unit that calculates the distance traveled by the submersible, and a memory unit that pre-stores first flow speed information that represents the relationship between the output of the propulsion unit and the flow speed measured by the measuring unit when the submersible is propelled in the propulsion direction from a state in which there is no water current around the submersible, and the calculation unit calculates the distance traveled by the submersible in the propulsion direction by correcting a reference travel distance calculated from the output of the propulsion unit and the operating time of the propulsion unit based on the actual flow speed measured by the measuring unit when the propulsion unit is operated at a predetermined output and a reference flow speed that corresponds to the predetermined output in the first flow speed information. Effect of the Invention

[0006] According to the present invention, the position of an underwater vehicle can be determined without being affected by multipath. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view showing a submersible of an underwater diving system. [Diagram 2] FIG. 2 is a block diagram showing the device configuration of the underwater diving system. [Diagram 3] FIG. 3 is a graph showing an example of flow velocity information. [Figure 4] FIG. 4 is a graph showing an example of travel distance information. [Diagram 5] FIG. 5 is a graph showing an example of the movement speed information. [Figure 6] FIG. 6 is a flowchart showing the steps of a method for calculating the distance traveled by the submersible vehicle by the propulsion units. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, one embodiment of the underwater submersion system will be described with reference to Figs. [Underwater Diving System 1] As shown in Fig. 1, the underwater submersible system 1 includes a submersible vehicle 10 and a control terminal 30. The submersible vehicle 10 is an unmanned submersible remotely operated from ground by the control terminal 30. The underwater submersible system 1 is used to inspect underwater structures such as the underwater walls of a dam.

[0009] The submersible 10 comprises a frame 11, a plurality of buoyant bodies 12, an underwater photography device 13, and a pressure-resistant container 14. The frame 11 has a substantially rectangular parallelepiped shape. The buoyant bodies 12, the underwater photography device 13, and the pressure-resistant container 14 are attached to the frame 11. The plurality of buoyant bodies 12 provide buoyancy to the submersible 10 so that the sinking force due to the weight of the submersible 10 and the buoyancy of the buoyant bodies 12 are balanced. The underwater photography device 13 comprises a box lens 13A, a camera 13B, and a lighting device 13C. The camera 13B is disposed within the box lens 13A. The lighting device 13C illuminates the imaging range of the camera 13B. The pressure-resistant container 14 houses a control unit 25 (see FIG. 2) and a battery.

[0010] The submersible 10 is equipped with a propulsion unit 15. The propulsion unit 15 is attached to the frame 11. The propulsion unit 15 propels the submersible 10 in any direction, forward, backward, left, right, up, or down, and rotates it around an up-down axis. The propulsion unit 15 can also drift the submersible 10. Drifting refers to simultaneously propelling the submersible 10 forward, backward, up, down, left, or right, and rotating around an up-down axis.

[0011] The submersible vehicle 10 is equipped with two forward and rearward thrusters 15A, two left and right thrusters 15B, and two up and down thrusters 15C. The forward and rearward thrusters 15A, the left and right thrusters 15B, and the up and down thrusters 15C are each an example of a propulsion unit 15. Note that in FIG. 1, one forward and rearward thruster 15A is illustrated, and the other forward and rearward thruster 15A is located behind other components of the submersible vehicle 10. Similarly, in FIG. 1, one left and right thruster 15B is illustrated, and the other left and right thruster 15B is located behind other components.

[0012] The front and rear thrusters 15A generate thrust in the front and rear direction. The left and right thrusters 15B generate thrust in the left and right direction. The up and down thrusters 15C generate thrust in the up and down direction. The thrust of the two front and rear thrusters 15A can be adjusted individually. Therefore, the two front and rear thrusters 15A generate a rotational moment around the up and down axis by balancing the thrust of both thrusters.

[0013] The submersible 10 is equipped with an attitude control device 16. The attitude control device 16 maintains the submersible 10 in a basic attitude. The attitude control device 16 includes a housing, a flywheel, a three-axis gimbal, a spindle motor, a gyro sensor, and the like. A control unit 25 controls the three-axis gimbal and the spindle motor of the attitude control device 16 based on the angular velocity detected by the gyro sensor of the attitude control device 16. As a result, the attitude control device 16 uses the gyro effect of the flywheel to cancel out the moment acting on the submersible 10 due to external forces such as water currents.

[0014] The submersible vehicle 10 includes a cleaning unit 17. The cleaning unit 17 is attached to the rear of the frame 11. The cleaning unit 17 is, for example, a rotary electric scraper. The cleaning unit 17 removes deposits from the surface of the inspection object.

[0015] The submersible vehicle 10 is equipped with a sonar 18. The sonar 18 is attached to the front of the frame 11. The sonar 18 is a multi-beam sonar that detects the distance and direction to an inspection object in front.

[0016] The submersible 10 is equipped with a measuring device 20. The measuring device 20 is attached to the frame 11. The measuring device 20 measures the relative flow speed of the water current that the submersible 10 receives. The submersible 10 is equipped with, for example, a front-rear current speed measuring device 20A, a left-right current speed measuring device 20B, and an upstream-downstream current speed measuring device 20C. The front-rear current speed measuring device 20A measures the flow speed of the water current flowing from the front to the rear, or from the rear to the front, of the submersible 10. The left-right current speed measuring device 20B measures the flow speed of the water current flowing from the left to the right, or from the right to the left, of the submersible 10. The upstream-downstream current speed measuring device 20C measures the flow speed of the water current flowing from the top to the bottom, or from the bottom to the top, of the submersible 10.

[0017] The measuring device 20 is, for example, a propeller-type current meter including a rotor 21 and a converter 22 (see FIG. 2). The rotor 21 rotates in a first rotation direction upon receiving a water current flowing in a first direction (e.g., from front to back), and rotates in a second rotation direction opposite to the first rotation direction upon receiving a water current flowing in a second direction (e.g., from back to front) opposite to the first direction.

[0018] As an example, the conversion unit 22 is an optical or magnetic rotary encoder that outputs a pulse wave according to the rotation angle of the rotor 21. The conversion unit 22 outputs a pulse wave capable of identifying the rotation direction of the rotor 21 to the control unit 25 every time the rotor 21 rotates a predetermined rotation angle. The control unit 25 measures the flow speed of the water current occurring around the submersible 10 based on the pulse wave output by the conversion unit 22.

[0019] The control terminal 30 is placed on land. The control terminal 30 is connected via a cable to a control unit 25 housed in a pressure-resistant container 14 of the submersible vehicle 10 placed underwater. The control terminal 30 controls the operation of each part of the submersible vehicle 10.

[0020] [Device configuration of Underwater Diving System 1] 2, the control unit 25 housed in the pressure-resistant container 14 is connected to the camera 13B, the propulsion unit 15, the attitude control device 16, the cleaning unit 17, the sonar 18, and the measuring instrument 20. The control unit 25 controls the operation of each part of the submersible 10 in response to signals from the control terminal 30. In other words, the control terminal 30 controls the operation of each part of the submersible 10 via the control unit 25. In addition to the above configuration, the control unit 25 may also control the operation of a device arranged on the submersible 10 (for example, the lighting device 13C).

[0021] The control unit 25 transmits data acquired from each part of the submersible 10 to the control terminal 30. For example, the control unit 25 transmits image data or video data captured by the camera 13B to the control terminal 30. The control unit 25 transmits the output of the propulsion machine 15 (for example, in kW) and the operating time of the propulsion machine 15 to the control terminal 30. The control unit 25 transmits the distance and direction to the inspection object detected by the sonar 18 to the control terminal 30. The control unit 25 transmits flow velocity data calculated based on the pulse waves output by the conversion unit 22 of the measuring instrument 20 to the control terminal 30.

[0022] The control terminal 30 comprises a control unit 31, a memory unit 32, an operation unit 33, a display unit 34, and a piloting unit 35. The control unit 31 includes a processor that executes various processes by software, such as a CPU or MPU. The control unit 31 controls, for example, the operation of each unit of the control terminal 30. Furthermore, the control unit 31 inputs signals to the control unit 25 for operating each unit of the submersible vehicle 10 according to inputs from the operation unit 33 and the piloting unit 35.

[0023] The storage unit 32 includes a temporary memory and a non-volatile memory. The temporary memory temporarily stores data to be processed by the control terminal 30. The temporary memory is, for example, a RAM. The non-volatile memory is, for example, a flash memory, an HDD, or an SSD.

[0024] The non-volatile memory stores flow velocity information in advance. The flow velocity information is data such as a table or a relational expression that associates the output (kW) of the propulsion unit 15 with the flow velocity (m / s) measured by the measuring device 20 corresponding to the propulsion direction when the submersible 10 is propelled in any one of the propulsion directions, forward, backward, left, right, up, or down. The measuring device 20 corresponding to the propulsion direction means a measuring device 20 that can measure the flow velocity of the water current flowing along the propulsion direction.

[0025] The non-volatile memory stores, for example, first flow speed information, second flow speed information, and third flow speed information as the flow speed information. The first flow speed information is data in which the output of the propulsion unit 15 and the flow speed measured by the measurement unit 20 are associated when the submersible 10 is propelled by operating the propulsion unit 15 from a state in which no water current is generated around the submersible 10. The second flow speed information is data in which the output of the propulsion unit 15 and the flow speed measured by the measurement unit 20 are associated when the submersible 10 is propelled from a state in which a water current is generated in the opposite direction to the propulsion direction for the submersible 10. The third flow speed information is data in which the output of the propulsion unit 15 and the flow speed measured by the measurement unit 20 are associated when the submersible 10 is propelled from a state in which a water current is generated in the forward direction, which is the same direction as the propulsion direction for the submersible 10. For example, the non-volatile memory stores first flow velocity information, second flow velocity information, and third flow velocity information for each of the forward, backward, left, right, up, and down propulsion directions.

[0026] The non-volatile memory stores travel distance information in advance. The travel distance information is data such as a table or a relational expression that associates the amount of power (kWs) consumed by the propulsion unit 15 when the submersible vehicle 10 is propelled from a reference position in the propulsion direction with the distance traveled (m) of the submersible vehicle 10 from a reference position in the propulsion direction. The amount of power (kWs) consumed by the propulsion unit 15 is the product of the output (kW) of the propulsion unit 15 and the operating time (s) of the propulsion unit 15. The propulsion direction is any one of forward, backward, left, right, up, and down.

[0027] The non-volatile memory stores, for example, first travel distance information, second travel distance information, and third travel distance information as travel distance information. The first travel distance information is data in which the amount of power consumed by the propulsion unit 15 is associated with the travel distance of the submersible 10 in the propulsion direction when the submersible 10 is propelled by operating the propulsion unit 15 from a state in which there is no water current around the submersible 10. The second travel distance information is data in which the amount of power consumed by the propulsion unit 15 is associated with the travel distance of the submersible 10 in the propulsion direction when the submersible 10 is propelled from a state in which there is a water current in the opposite direction to the propulsion direction for the submersible 10. The third travel distance information is data in which the amount of power consumed by the propulsion unit 15 is associated with the travel distance of the submersible 10 in the propulsion direction when the submersible 10 is propelled from a state in which there is a water current in the forward direction, which is the same direction as the propulsion direction for the submersible 10. For example, the non-volatile memory stores first movement distance information, second movement distance information, and third movement distance information for each of the forward, backward, left, right, up, and down directions.

[0028] The non-volatile memory stores travel speed information in advance. The travel speed information is data such as a table or a relational expression that associates the flow speed (m / s) measured by the measuring device 20 corresponding to the propulsion direction with the travel speed (m / s) of the submersible 10 when the submersible 10 moves in response to the surrounding water currents while the propulsion device 15 is not operating. For example, the non-volatile memory stores travel speed information for the cases where the propulsion directions are forward, backward, left, right, up, and down.

[0029] A travel distance calculation program is stored in the non-volatile memory. The control unit 31 functions as a calculation unit 31A by executing the travel distance calculation program. The calculation unit 31A calculates the travel distance of the submersible vehicle 10 caused by the propulsion unit 15, for example, when the propulsion unit 15 is operating. The calculation unit 31A calculates the travel distance of the submersible vehicle 10 caused by a water current received by the submersible vehicle 10, for example, when the propulsion unit 15 is not operating.

[0030] The position of the submersible 10 underwater and image data or video data captured by the camera 13B are stored in association with each other in the storage unit 32. For example, the storage unit 32 stores, with an arbitrary position underwater set as a reference position, the movement distances (coordinates) in the forward / backward, left / right, and up / down directions from the reference position in association with the image data or video data captured by the camera 13B.

[0031] The operation unit 33 is an input device, such as a keyboard or a pointing device, that allows the operator to operate the control terminal 30. The display unit 34 is a display that displays various information. As an example, the control terminal 30 may be equipped with a touch panel in which the operation unit 33 and the display unit 34 are integrated. The control unit 35 is an input device that allows the operator to operate the submersible 10 via the control terminal 30. Note that the operation unit 33 may also serve as the control unit 35.

[0032] [Flow velocity information] 3, a waveform 101 in a graph 100 is an example of first flow velocity information stored in the storage unit 32. A waveform 102 is an example of second flow velocity information stored in the storage unit 32. A waveform 103 is an example of third flow velocity information stored in the storage unit 32.

[0033] The horizontal axis of graph 100 represents the output OP (kW) of the propulsion unit 15 when the submersible 10 is propelled in a predetermined propulsion direction. The vertical axis of graph 100 represents the flow velocity V (m / s) measured by the measurement device 20 corresponding to the propulsion direction when the submersible 10 is propelled in the predetermined propulsion direction.

[0034] The flow velocity V is the magnitude of the flow velocity in the direction opposite to the propulsion direction of the submersible 10. The flow velocity V is the difference between the movement speed of the submersible 10 and the flow speed of the surrounding water when the submersible 10 is propelled in a specified propulsion direction, that is, the relative speed of the surrounding water current with respect to the movement speed of the submersible 10. Therefore, when the submersible 10 is propelled in the propulsion direction from a reference position by operating the propulsion device 15, the value of the flow velocity V measured by the measurement device 20 changes depending on the presence or absence of a water current around the submersible 10 and the direction of the water current with respect to the propulsion direction.

[0035] Waveform 101 is acquired by operating propulsion machine 15 when there is no water current around submersible vehicle 10. For example, when submersible vehicle 10 is propelled forward when there is no water current around submersible vehicle 10, the relative flow velocity V measured by measurement device 20, which is the flow velocity of the water current that submersible vehicle 10 receives from the front, increases as the output power OP of propulsion machine 15 increases.

[0036] The waveform 102 is obtained by operating the propulsion machine 15 in a state in which a water current having a first flow velocity in a direction opposite to the propulsion direction is generated relative to the submersible vehicle 10. For example, when the submersible vehicle 10 is propelled forward in a state in which a water current is generated from the front to the rear relative to the submersible vehicle 10, the flow velocity V of the waveform 102 is greater than that of the waveform 101 by the amount of the water current from the front. Therefore, when the propulsion machine 15 is operated at a predetermined output OP1, the flow velocity V2 of the waveform 102 is greater than the flow velocity V1 of the waveform 101.

[0037] Waveform 103 is obtained by operating propulsion unit 15 in a state in which a water current having a second flow velocity in the same forward direction as the propulsion direction is generated relative to submersible vehicle 10. For example, when submersible vehicle 10 is propelled forward in a state in which a water current is generated from the rear to the front relative to submersible vehicle 10, the flow velocity V of waveform 103 becomes smaller than that of waveform 101 by the amount of the water current from the rear. Therefore, when propulsion unit 15 is operated at a predetermined output OP1, flow velocity V3 of waveform 103 becomes smaller than flow velocity V1 of waveform 101.

[0038] [Travel distance information] 4, a waveform 201 in the graph 200 is an example of first moving distance information stored in the storage unit 32. A waveform 202 is an example of second moving distance information stored in the storage unit 32. A waveform 203 is an example of third moving distance information stored in the storage unit 32.

[0039] The horizontal axis of graph 200 represents the power consumption P (kWs) of the propulsion unit 15 when the submersible 10 is propelled in a predetermined propulsion direction. The vertical axis of graph 200 represents the travel distance D (m) of the submersible 10 in the propulsion direction when the submersible 10 is propelled in the predetermined propulsion direction from a reference position.

[0040] Waveform 201 is acquired by operating the propulsion machine 15 when there is no water current around the submersible 10. For example, when the submersible 10 is propelled forward when there is no water current around the submersible 10, the travel distance D of the submersible 10 in the propulsion direction increases as the power consumption P of the propulsion machine 15 increases.

[0041] Waveform 202 is obtained by operating the propulsion unit 15 in a state in which a water current having a first flow velocity in a direction opposite to the propulsion direction is occurring with respect to the submersible vehicle 10. In waveform 202, the water resistance during movement is large by the amount of the water current occurring in the direction opposite to the propulsion direction, so the travel distance D is smaller than that of waveform 201. Therefore, when the propulsion unit 15 is operated at a predetermined power consumption amount P1, the travel distance D2 of waveform 202 is smaller than the travel distance D1 of waveform 201.

[0042] Waveform 203 is acquired by operating the propulsion unit 15 in a state in which a water current having a second flow velocity in the same forward direction as the propulsion direction is generated relative to the submersible 10. For example, in waveform 203, the water resistance during movement is smaller by the amount of water current generated in the same forward direction as the propulsion direction, and therefore the travel distance D is greater than that of waveform 201. Therefore, when the propulsion unit 15 is operated at a predetermined power consumption P1, the travel distance D3 of waveform 203 is greater than the travel distance D1 of waveform 201.

[0043] [Moving speed information] 5, a waveform 301 in graph 300 is an example of travel speed information stored in memory unit 32. The horizontal axis of graph 300 represents the flow speed V (m / s) measured by measurement device 20 corresponding to the propulsion direction when the submersible 10 moves in response to the surrounding water currents when the propulsion device 15 is not operating. The vertical axis of graph 300 represents the travel speed v (m / s) of the submersible 10 when the submersible 10 moves in response to the surrounding water currents when the propulsion device 15 is not operating.

[0044] The waveform 301 is obtained by using a test water tank, such as a swimming pool, in which the speed of the water current received by the submersible 10 can be changed. For example, the waveform 301 is obtained by measuring the flow speed V measured by the measuring device 20 and the movement speed v of the submersible 10 in a test water tank when a water current of a predetermined flow speed is generated around the submersible 10 without operating the propulsion device 15. The movement speed v of the submersible 10 can be the value at the time when the value of the flow speed V measured by the measuring device 20 becomes approximately constant, that is, the value at the time when the submersible 10 reaches a constant movement speed v by receiving the water current.

[0045] In waveform 301, as the speed of the water current that the submersible 10 receives when the propulsion machine 15 is not operating, that is, the current speed V measured by the measuring machine 20 corresponding to the propulsion direction, increases, the movement speed v of the submersible 10 also increases. On the other hand, if the speed of the water current that the submersible 10 receives is slow, the submersible 10 remains in place without moving, and therefore in waveform 301 the movement speed v of the submersible 10 does not increase until the current speed V reaches a predetermined magnitude.

[0046] [Operation and usage of the underwater diving system 1] The operation and use of the underwater diving system 1 will now be described. First, an operator throws the submersible vehicle 10 into the water. The position of the submersible vehicle 10 at this time is defined as the landing position. The operator then operates the control terminal 30 to operate the camera 13B, the lighting device 13C, and the sonar 18. Then, an image or video of the foreground of the submersible vehicle 10 captured by the camera 13B is displayed on the display unit 34. A distribution map of echo intensity is also displayed on the display unit 34.

[0047] Then, the operator operates the control terminal 30 to operate the propulsion unit 15 and move the submersible 10 close to the object to be inspected. When the submersible 10 approaches the object to be inspected, the rear of the submersible 10 is directed toward the object to be inspected and the cleaning unit 17 is brought into contact with the object to be inspected. The position of the submersible 10 at this time is defined as the cleaning start position. The cleaning unit 17 is then operated to peel off any deposits attached to the object to be inspected. At this time, the propulsion unit 15 is operated to move the submersible 10 along the object to be inspected. After cleaning is completed, the cleaning unit 17 is stopped. The position of the submersible 10 at this time is defined as the cleaning completion position.

[0048] Next, the worker operates the control terminal 30 to operate the propulsion unit 15 and orient the front of the submersible 10 toward the object to be inspected. Then, recording of image data or video data of the view in front of the submersible 10 in the memory unit 32 begins. The position of the submersible 10 at this time is set as the recording start position. The recording start position may be the same position as the cleaning completion position. In this state, the worker operates the control terminal 30 to operate the propulsion unit 15 and move the submersible 10 along the object to be inspected. As a result, while moving along the object to be inspected, the submersible 10 acquires image data or video data that can be used to check for the presence or absence of defects in the object to be inspected.

[0049] Furthermore, the storage unit 32 stores, for each predetermined period, image data acquired at that time in association with the travel distance D from the recording start position of the submersible 10 at that time. This makes it possible to identify the position on the inspection object where the image data was acquired. In other words, when a defect is confirmed in the image data, it is possible to accurately identify the position where the defect occurred on the inspection object.

[0050] [Method of calculating the travel distance D of the submersible 10 by the propulsion unit 15] A method for calculating the travel distance of the submersible 10 when the submersible 10 is propelled in a propulsion direction (for example, forward) from an arbitrary reference position underwater by operating the propulsion device 15 will be described below with reference to Fig. 6. Here, as an example, a method for calculating the travel distance D when the submersible 10 is propelled in the propulsion direction while a water current is occurring in the opposite direction to the propulsion direction of the submersible 10 will be described. The reference position may be the water landing position, the cleaning start position, the cleaning completion position, or the recording start position.

[0051] 6, the method for calculating the distance traveled D of the submersible 10 by the propulsion machines 15 includes the processing of steps S1 to S7. The processing of steps S1 to S7 is executed by calculation unit 31A. First, calculation unit 31A obtains from control unit 25 the output OP1 when the propulsion machines 15 are operated to propel the submersible 10 in the propulsion direction (step S1).

[0052] Next, based on the first flow velocity information stored in the memory unit 32, the calculation unit 31A calculates the reference flow velocity V1 measured by the measuring device 20 when the propulsion unit 15 is operated at output OP1 from a state in which there is no water flow around the submersible vehicle 10 (step S2).

[0053] Next, calculation section 31A obtains from control unit 25 actual value VA of flow velocity V measured by measuring instrument 20 when submersible vehicle 10 is propelled in the propulsion direction from the reference position by operating propulsion device 15 at a predetermined output OP1 (step S3). Note that here, actual value VA of measuring instrument 20 that measures the flow velocity of the water current along the propulsion direction of submersible vehicle 10 is obtained, out of the multiple measuring instruments 20.

[0054] Next, the calculation unit 31A calculates the difference ΔVA between the actual measurement value VA and the reference flow velocity V1 (step S4). As shown in Fig. 3, the reference flow velocity V1 is the value of the flow velocity V corresponding to a predetermined output OP1 in a waveform 101 that is the first flow velocity information. Also, as an example, the flow velocity of the water current occurring in the direction opposite to the propulsion direction of the submersible 10 is assumed to be smaller than the first flow velocity when the waveform 102 that is the second flow velocity information is acquired. Therefore, the actual measurement value VA measured by the measuring device 20 is larger than the value of the reference flow velocity V1 corresponding to the predetermined output OP1 in the waveform 102, and smaller than the value of the flow velocity V2 corresponding to the output OP1. Also, the difference ΔVA between the actual measurement value VA and the reference flow velocity V1 is expressed as ΔVA = VA - V1.

[0055] 6, the calculation unit 31A acquires the power consumption P1 of the propulsion machine 15 when the propulsion machine 15 is operated to propel the submersible vehicle 10 in the propulsion direction (step S5). In detail, the calculation unit 31A acquires the operation time of the propulsion machine 15 from the control unit 25, and calculates the power consumption P1 of the propulsion machine 15 from the output OP1 of the propulsion machine 15 and the operation time of the propulsion machine 15.

[0056] Next, the calculation unit 31A calculates a reference travel distance D1 when the propulsion unit 15 is operated at power consumption P1 from a state in which there is no water current around the submersible 10, based on the first travel distance information stored in the memory unit 32 (step S6).

[0057] Next, calculation unit 31A calculates actual travel distance DA by correcting reference travel distance D1 based on difference ΔVA (step S7). Difference ΔVA has a positive correlation with the magnitude of resistance force that is generated by a water current in the opposite direction to the propulsion direction of the submersible 10 when the submersible 10 is propelled in the propulsion direction. Therefore, by correcting reference travel distance D1 based on difference ΔVA, the reduction in travel distance D due to resistance force generated by a water current in the opposite direction to the propulsion direction of the submersible 10 can be reflected in actual travel distance DA.

[0058] As shown in FIG. 3, in detail, the calculation unit 31A first calculates the difference ΔV2 between the reference flow velocity V1 and the flow velocity V2 corresponding to the output OP1 in the waveform 102. The difference ΔV2 is expressed as ΔV2=V2-V1. Then, the calculation unit 31A calculates a first correction coefficient. The first correction coefficient is the ratio of the difference ΔVA between the actual measurement value VA and the reference flow velocity V1 to the difference ΔV2 between the reference flow velocity V1 and the flow velocity V2. The first correction coefficient is expressed as ΔVA / ΔV2.

[0059] As shown in FIG. 4, the calculation unit 31A then calculates a difference ΔD2 between a reference moving distance D1 and a moving distance D2 corresponding to the power consumption P1 in the waveform 202. Furthermore, the calculation unit 31A calculates a correction amount X1 by multiplying the difference ΔD2 by a first correction coefficient (ΔVA / ΔV2). The correction amount X1 is expressed as X1=ΔD2×(ΔVA / ΔV2). Then, the calculation unit 31A calculates an actual moving distance DA by subtracting the correction amount X1 from the reference moving distance D1. The actual moving distance DA is expressed as DA=D1−X1.

[0060] The above procedure calculates the actual travel distance DA, which is the travel distance D of the submersible 10 due to the propulsion machine 15. The calculation of the actual travel distance DA is performed at a predetermined cycle. The calculated actual travel distance DA is stored in the memory unit 32 in association with image data acquired by the submersible 10. The actual travel distance DA can be calculated using a similar concept even when the submersible 10 is propelled in the propulsion direction while there is a water current in the same forward direction as the propulsion direction of the submersible 10. The travel distance of the submersible 10 in three dimensional directions from a reference position can be calculated by calculating the actual travel distance DA for each of the forward, backward, left, right, up, and down directions.

[0061] [Method of calculating the travel distance D of the submersible 10 when the propulsion unit 15 is not in operation] Even when the propulsion device 15 is not in operation, if there is a water current around the submersible 10, the submersible 10 moves due to the surrounding water current. In this case, the calculation unit 31A calculates the distance D traveled by the submersible 10 due to the water current based on the flow velocity V measured by the measurement device 20.

[0062] In detail, the calculation unit 31A calculates the movement speed v of the submersible 10 corresponding to the flow speed V measured by the measuring instrument 20 in the movement speed information (waveform 301) stored in the memory unit 32. The calculation unit 31A then calculates the movement distance D traveled by the submersible 10 due to the water current from the movement speed v of the submersible 10. Through the above procedure, the movement distance D traveled by the submersible 10 due to the water current when the propulsion unit 15 is not operating is calculated.

[0063] [Operation of the embodiment] In the above-described method of calculating the travel distance D of the submersible 10 by the propulsion unit 15, the actual travel distance DA is calculated by correcting the reference travel distance D1 calculated from the output OP1 of the propulsion unit 15 and the operating time of the propulsion unit 15 based on the actual measurement value VA and the reference flow velocity V1. That is, the calculation unit 31A corrects the reference travel distance D1 so that the correction amount X1 increases as the deviation between the actual measurement value VA and the reference flow velocity V1 increases. This allows the influence of the water current occurring around the submersible 10 to be reflected in the actual travel distance DA.

[0064] [Effects of the embodiment] According to the embodiment, the following effects can be obtained. (1) According to the above-described method for calculating the travel distance D of the submersible 10 by the propulsion device 15, it is possible to calculate the actual travel distance DA of the submersible 10 in the propulsion direction while reflecting an increase or decrease in the travel distance D due to water currents occurring around the submersible 10. This makes it possible to grasp the position of the submersible 10 without being affected by multipath.

[0065] (2) According to the measuring device 20 equipped with the rotor 21 and the conversion unit 22, the flow velocity V of the water current generated around the submersible 10 can be measured from the rotation angle of the rotor 21. (3) The submersible 10 is equipped with multiple measuring devices 20, including the forward / backward current velocity measuring device 20A, the left / right current velocity measuring device 20B, and the upstream / downstream current velocity measuring device 20C, so that the actual travel distances DA for the front, rear, left, right, up, and down directions can be calculated. This makes it possible to calculate the travel distances of the submersible 10 in three dimensional directions from a reference position.

[0066] (4) When the propulsion unit 15 is not operating, the distance D traveled by the submersible 10 in response to the water current can be calculated based on the flow velocity V measured by the measuring device 20, thereby making it possible to determine the position of the submersible 10 without being affected by multipath.

[0067] [Example of change] The above embodiment can be modified as follows. The underwater submersion system 1 may be configured to calculate the actual travel distance DA in at least one of the directions forward, backward, left, right, up, and down. In this case, it is sufficient to have a measuring device 20 that can measure the flow velocity V in at least the direction of forward, backward, left, right, up, and down for calculating the actual travel distance DA.

[0068] The measuring device 20 is not limited to a propeller-type current meter having a rotor 21 and a converter 22. For example, the measuring device 20 may be an electromagnetic current meter that detects the magnitude of electromotive force generated when a water flow passes through a magnetic field of a coil through which a current flows.

[0069] The method of calculating the actual travel distance DA of the submersible 10 by the propulsion machine 15 is not limited to the procedure of steps S1 to S7. In other words, it is sufficient to calculate the actual travel distance DA reflecting an increase or decrease in the travel distance D due to the water current occurring around the submersible 10 by correcting the reference travel distance D1 according to the actual measurement value VA of the flow velocity V measured by the measurement machine 20 when the submersible 10 is propelled by the propulsion machine 15. For example, the calculation unit 31A first calculates a ratio VA / V1 between the actual measurement value VA of the flow velocity V measured by the measurement machine 20 and the reference flow velocity V1 corresponding to the output OP1 of the propulsion machine 15 in the first flow velocity information. The ratio VA / V1 of the actual measurement value VA to the reference flow velocity V1 has a positive correlation with the magnitude of resistance due to the water current in the propulsion direction of the submersible 10. The calculation unit 31A may then calculate the actual travel distance DA by correcting the reference travel distance D1 using the ratio VA / V1 of the actual measurement value VA to the reference flow velocity V1. For example, the calculation unit 31A may calculate the actual movement distance DA by multiplying the reference movement distance D1 by a correction coefficient, which is the inverse of the ratio VA / V1 of the actual measurement value VA and the reference flow velocity V1.

[0070] In the underwater diving system 1, instead of a configuration in which the calculation of the traveled distance D is performed by the calculation section 31A (control section 31) of the control terminal 30, the control unit 25 of the submersible vehicle 10 may calculate the traveled distance D. That is, the control unit 25 of the submersible vehicle 10 may be equipped with a calculation section. Also, instead of a configuration in which the current speed information, traveled distance information, and travel speed information are stored in the memory section 32 of the control terminal 30, these pieces of information may be stored in a memory section equipped in the control unit 25. Also, these pieces of information may be saved in a server connected to the control terminal 30 via a network line.

[0071] In the underwater diving system 1, the submersible 10 has been illustrated as operating in response to the operation of the control terminal 30 by an operator, but instead, the object to be inspected may be photographed while moving along a preset route by fully automatic control. Alternatively, the submersible 10 may be driven by semi-automatic control that combines the operation of the operator with automatic control. In this case, by calculating the actual travel distance DA that reflects the increase or decrease in the travel distance D due to the water current, the exact position underwater can be grasped without the operator having to adjust the position.

[0072] [Note] According to the above embodiment and its modifications, the following technical ideas can be derived. (Appendix 1) a submersible vehicle having a propulsion unit that generates a propulsive force in a propulsion direction; a measuring device that measures a flow velocity of a water current received by the submersible vehicle relative to the submersible vehicle; A calculation unit that calculates a travel distance of the submersible vehicle, The calculation unit calculates a distance traveled by the submersible vehicle in response to a water current based on the flow velocity measured by the measurement device when the propulsion device is not in operation. Underwater diving system.

[0073] According to the above Supplementary Note 1, when the propulsion device is not operating, the distance traveled by the submersible vehicle in response to the water current can be calculated based on the flow speed measured by the measuring device, thereby making it possible to determine the position of the submersible vehicle without being affected by multipath.

[0074] (Appendix 2) The measuring instrument is one of a plurality of measuring instruments, The plurality of measuring devices measure the flow velocity in each of the directions of front, rear, left, right, up, and down. 2. An underwater submersible system as described in claim 1.

[0075] According to the above Supplementary Note 2, the moving distances in the forward, backward, left, right, up, and down directions can be calculated, and therefore the moving distances in the three-dimensional directions of the submersible vehicle can be calculated. [Explanation of symbols]

[0076] ΔD2, ΔV2, ΔVA...difference, D, D1~D3...travel distance, D1...reference travel distance, DA...actual travel distance, OP, OP1...output, P, P1...power consumption, S1~S7...step, V, V1~V3...flow speed, V1...reference flow speed, VA...actual measurement value, v...travel speed, X1...correction amount, 1...underwater diving system, 10...submersible vehicle, 11...frame, 12...buoyancy body, 13...underwater photography device, 13A...box glasses, 13B...camera, 13C...lighting device, 14...pressure-resistant container, 15...propulsion unit, 15A...front and rear switches raster, 15B...left and right thrusters, 15C...up and down thrusters, 16...attitude control device, 17...cleaning unit, 18...sonar, 20...measuring instrument, 20A...front and rear flow velocity measuring instrument, 20B...left and right flow velocity measuring instrument, 20C...up and down flow velocity measuring instrument, 21...rotor, 22...conversion unit, 25...control unit, 30...control terminal, 31...control unit, 31A...calculation unit, 32...memory unit, 33...operation unit, 34...display unit, 35...control unit, 100, 200, 300...graphs, 101-103, 201-203, 301...waveform.

Claims

1. a submersible vehicle having a propulsion unit that generates a propulsive force in a propulsion direction; a measuring device that measures a flow velocity of a water current received by the submersible vehicle relative to the submersible vehicle in the propulsion direction; A calculation unit that calculates a travel distance of the submersible vehicle; a memory unit that pre-stores first flow velocity information that indicates a relationship between the output of the propulsion unit and the flow velocity measured by the measurement device when the submersible is propelled in the propulsion direction from a state in which no water current is generated around the submersible, The calculation unit calculates the travel distance of the submersible vehicle in the propulsion direction by correcting a reference travel distance calculated from the power of the propulsion machine and the operation time of the propulsion machine based on an actual value of the flow speed measured by the measuring device when the propulsion machine is operated at a predetermined output and a reference flow speed corresponding to the predetermined output in the first flow speed information. Underwater diving system.

2. The measuring device includes a rotor that receives a water current around the submersible vehicle and rotates in accordance with a relative flow speed of the water current in the propulsion direction, and a converter that outputs a pulse wave in accordance with a rotation angle of the rotor.

2. The underwater submersible system of claim 1.

3. The measuring instrument is one of a plurality of measuring instruments. The plurality of measuring devices measure flow velocities in the forward, backward, left, right, up, and down directions, The storage unit stores in advance the first flow velocity information when the propulsion direction is each of the forward, backward, left, right, up, and down directions.

3. An underwater submersible system according to claim 1 or 2.

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