Underwater sensor system, control device, control method, and program

Abstract

Provided is an underwater sensor system comprising: sensors 1 that are installed on a cable 5 and disposed underwater; winders 2 for adjusting the length of the cable 5; and propellers 3 that are installed on the cable 5 and propel the sensors 1 underwater via the cable 5.

Description

Underwater sensor system, control device, control method and program

[0001] The present disclosure relates to an underwater sensor system, a control device, a control method, and a program.

[0002] In recent years, from the viewpoint of environmental conservation, investigations have been conducted into aquatic environments such as the sea, rivers, small ponds, etc. Non-Patent Document 1 describes a remote water thermometer for measuring the temperature of underwater water.

[0003] Aquasound Co., Ltd., "Remote Water Thermometer," [online], Internet <URL: https: / / aqua-sound.com / product / %e3%83%aa%e3%83%a2%e3%83%bc%e3%83%88%e6%b0%b4%e6%b8%a9%e8%a8%88 / >

[0004] The remote water thermometer in Non-Patent Document 1 has multiple water thermometers (pingers) placed at different depths in the water to measure water temperatures at multiple depths at once. However, Non-Patent Document 1 has a problem in that the water thermometer placed in the sea is carried away by ocean currents, resulting in the measurement of water temperature at a depth different from the originally intended depth.

[0005] The present disclosure has been made in consideration of the above circumstances, and an object of the present disclosure is to provide a technology for suppressing fluctuations in the depth of a sensor placed underwater.

[0006] In order to achieve the above object, one aspect of the present disclosure is an underwater sensor system comprising a sensor attached to a cable and placed underwater, a winding machine for adjusting the length of the cable, and a propeller attached to the cable and propelling the sensor underwater via the cable.

[0007] One aspect of the present disclosure is a control device that includes an acquisition unit that acquires a first depth at which a sensor is located from a sensor attached to a cable and placed underwater, and a control unit that, if the first depth is shallower than a second depth at which the sensor should be located, sends an instruction to a winding machine to pull out the cable and sends an instruction to a propulsion unit to propel the sensor in a deeper direction, and, if the first depth is deeper than the second depth, sends an instruction to the winding machine to wind up the cable.

[0008] One aspect of the present disclosure is a control method performed by a control device, which obtains a first depth at which a sensor is located, from a sensor attached to a cable and placed underwater; if the first depth is shallower than a second depth at which the sensor should be located, sends an instruction to a winding machine to pull out the cable and an instruction to a propulsion device to propel the sensor in a deeper direction; and if the first depth is deeper than the second depth, sends an instruction to the winding machine to wind up the cable.

[0009] One aspect of the present disclosure is a program that causes a computer to function as an acquisition unit that acquires a first depth at which a sensor is located from a sensor attached to a cable and placed underwater, and a control unit that, if the first depth is shallower than a second depth at which the sensor should be located, sends an instruction to a winding machine to pull out the cable and sends an instruction to a propulsion unit to propel the sensor in a deeper direction, and, if the first depth is deeper than the second depth, sends an instruction to the winding machine to wind up the cable.

[0010] According to the present disclosure, it is possible to provide a technique for suppressing fluctuations in the depth of a sensor placed underwater.

[0011] FIG. 1A is a diagram showing a plurality of sensors arranged underwater. FIG. 1B is a diagram showing sensors being carried away by ocean currents. FIG. 2 is a configuration diagram of an underwater sensor system of this embodiment. FIG. 3A is a schematic diagram of a propeller. FIG. 3B is a schematic diagram showing an example of a propeller's oscillating function. FIG. 3C is a schematic diagram showing another example of a propeller's oscillating function. FIG. 4 is a block diagram showing the configuration of a control device. FIG. 5 is an example of a hardware configuration.

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0013] 1A shows a method for observing environmental data (environmental information) at different depths underwater using multiple sensors. In the illustrated example, a cable with multiple sensors installed in series is attached to an object floating on the water surface, such as a buoy, and the cable is suspended underwater. Here, the multiple sensors are connected in series to the cable at predetermined intervals, and each sensor measures environmental data (e.g., water temperature) at its own depth, n1, n2, n3, or n4.

[0014] However, when observing environmental data at a plurality of depths using the method shown in FIG. 1A, the sensor may be swept away by the influence of, for example, ocean currents, and the depth to be observed may change.

[0015] 1B shows a sensor suspended in water that has been carried away by ocean currents and is positioned at a depth different from the original depth shown in FIG. 1A. In the illustrated example, the second and subsequent sensors from the buoy have been carried away by ocean currents to a position shallower than the original depth shown in FIG. 1A. This changes the observation depth of each sensor. In this embodiment, the objective is to suppress fluctuations in the depth of sensors suspended in water and maintain a constant depth for each sensor.

[0016] 2 is a diagram showing the configuration of the underwater sensor system of this embodiment. The underwater sensor system shown in the figure has at least one set including a sensor 1, a winding machine 2, and a propeller 3. Here, two sensors 1-1 and 1-2 (hereinafter referred to as "sensor 1"), two winding machines 2-1 and 2-2 (hereinafter referred to as "winding machine 2"), and two propellers 3-1 and 3-2 (hereinafter referred to as "propeller 3") are shown, but this is not limiting.

[0017] The sensor 1 is attached to a cable 5 and placed underwater. The underwater sensor system shown in FIG. 2 includes multiple sensors 1, but may include only one sensor. In this embodiment, multiple sensors 1 are attached to the cable 5, and each sensor 1 is placed corresponding to multiple depths underwater. That is, each sensor 1 observes and measures the underwater environment (e.g., water temperature) at a predetermined depth. The cable 5 is tethered to a buoy 6 floating on the water surface. Note that the object 9 is not limited to a buoy, and may be any object 9 floating on the water surface.

[0018] The sensor 1 may be, for example, a CTD (Conductivity Temperature Depth Profiler) sensor. The CTD sensor observes electrical conductivity, water temperature, and depth (pressure). The CTD sensor can calculate salinity from the observed electrical conductivity, water temperature, and depth (pressure), and is one of the measuring instruments commonly used in oceanographic observation sites.

[0019] The sensor 1 of this embodiment is equipped with a depth gauge, and before measuring environmental data such as water temperature, the depth gauge measures the underwater depth at which the sensor is located and transmits the measured depth to the control device 7. The control device 7 controls the reel 2 and the propeller based on the depth transmitted from the sensor, and adjusts the depth of the sensor 1 to the original depth. The sensor 1 then measures environmental data such as water temperature at the original depth and transmits the observation data to the control device 7 or another device.

[0020] The winding machine 2 is connected to the cable 5 and adjusts the length of the cable 5. Specifically, the winding machine 2 adjusts the length of the cable 5 by pulling out or winding up the cable 5. A winding machine 2 is provided for each sensor 1, and is attached to the cable 5 at a position above the corresponding sensor 1. The winding machine 2 may be, for example, an electric reel.

[0021] The winders 2 are arranged between the buoy 6 and the sensor 1, or between adjacent sensors 1 above and below. Here, the first-stage winder 2-1 is located between the buoy 6 and the propeller 3-1, and the second-stage winder 2 is located between the upper-stage sensor 1-1 and the propeller 3-2. The winders 2 from the third stage onwards are similar to the second-stage winder 2.

[0022] The winder 2 adjusts the length of the cable 5 between the buoy and the sensor or between the sensors. Depending on its installation position, the winder 2 may take up or draw out the cable 5 above the winder 2 (between the winder 2 and the buoy 6 or the upper sensor 1). The winder 2 may also take up or draw out the cable 5 below the winder 2 (between the winder 2 and the propeller 3). The winder 2 may also take up or draw out the cable 5 both above and below the winder 2.

[0023] The propeller 3 is attached to the cable 5 and propels the sensor 1 through the water via the cable 5. Specifically, the propeller 3 generates a propulsive force so that the depth in the water at which the sensor 1 is located coincides with the depth at which the sensor 1 should be located. The propeller 3 may be, for example, a screw.

[0024] A propeller 3 is provided for each sensor 1 and is arranged between the buoy 6 and the sensor 1, or between adjacent sensors 1 above and below. Here, the propeller 3 is attached to the cable 5 at a position above the corresponding sensor 1. The propeller 3 is arranged close to the corresponding sensor 1, and is controlled to be off when the sensor 1 observes environmental data so as not to disturb the surrounding environment. Alternatively, the propeller 3 may be arranged at a predetermined distance from the sensor 1 so as not to disturb the observation environment when the sensor 1 observes environmental data.

[0025] The propeller 3 rotates a propeller (screw propeller) in water to create lift in the direction of the rotation axis, thereby generating thrust.

[0026] As shown in Figure 3A, a weight 31 is mounted on the bottom of the propeller 3 (on the depth side, such as the seabed). This prevents the propeller 3 from turning upside down in the water. Furthermore, as shown in Figures 3B and 3C, the propeller 3 has a swiveling function. The propeller 3 shown in Figure 3B swivels to extend and rotate the propeller sideways, thereby propelling in the direction opposite to the direction in which the propeller is extended. The propeller 3 shown in Figure 3C swivels to bend and rotate the propeller upward (towards the water surface), thereby propelling downward (in the depth direction).

[0027] The propeller of the propeller 3 may be a variable pitch propeller, allowing the thrust to be freely changed. A variable pitch propeller is a screw propeller that can freely change the pitch (angle) of the propeller blades. By changing the pitch, it is possible to obtain thrust in any direction while maintaining a constant rotation direction and rotation speed. The propeller 3 may also be equipped with multiple propellers.

[0028] The sensor 1, the reel 2, and the propeller 3 may each be equipped with a battery such as a cell as a power source, or may be driven by power supplied from a power source (not shown) located on the buoy 6. When power is supplied from the power source on the buoy 6, power may be supplied wirelessly or by wire via a cable 5.

[0029] The underwater sensor system of this embodiment may include a control device 7. In the example shown in Fig. 2, the control device 7 is built into the buoy 6, but this is not limiting. The control device 7 may be installed on the cable 5 and placed underwater, or may be placed in a location separate from the underwater sensor 1, reel machine 2, and propeller 3, such as on land or a ship. When the control device 7 is placed in a location separate from the underwater sensor 1, reel machine 2, and propeller 3, the control device 7 transmits and receives data to and from the sensor 1, reel machine 2, and propeller 3 via wireless communication.

[0030] 4 is a configuration diagram showing an example of the configuration of the control device 7 of this embodiment. The illustrated control device 7 includes an acquisition unit 71, a control unit 72, and a storage unit 73, and controls the winding machine 2 and the thruster 3.

[0031] The acquisition unit 71 acquires the depth at which each sensor 1 is located (hereinafter referred to as the "first depth") from each sensor 1 installed on the cable 5 and placed underwater. Each sensor 1 measures the first depth at which the sensor 1 is located in the water at a predetermined timing (for example, periodically) and transmits the measured first depth to the control device 7. The first depth (first depth data) is assumed to include the sensor ID (identification information) of the sensor 1.

[0032] The control unit 72 controls the winding machine 2 and / or the propeller 3 corresponding to the sensor 1 based on the acquired first depth of the sensor 1. That is, the control unit 72 performs the following process for each sensor 1.

[0033] First, the control unit 72 compares the acquired first depth with the depth that the sensor 1 should be at (hereinafter referred to as the “second depth”) stored in the storage unit 73 .

[0034] If the acquired first depth is shallower than the second depth, the control unit 72 sends an instruction to the winder 2 to unwind the cable 5 and an instruction to the propeller 3 to propel the sensor 1 in a deeper direction. For example, if the difference between the first depth and the second depth is X, the control unit 72 lengthens the cable 5 of the winder 2 by X. Then, the control unit 72 bends the neck of the propeller of the propeller 3 upward to propel the propeller 3 downward by X, and moves the sensor connected via the cable 5 to its original second depth.

[0035] At this time, if the length of the cable 5 corresponding to the sensor 1 is longer than a predetermined length, the control unit 72 may wind up the excess cable 5 that has been unwound in preparation for the next alignment. For example, the control unit 72 may wind up the excess cable 5 with the winder 2 while propelling the propeller of the propeller 3 horizontally. If the sensor 1 or the control unit 72 can also detect the position of the sensor 1 in the horizontal direction and it is desired to align the sensor 1 horizontally with the upper and lower sensors, the control unit 72 may turn the neck of the propeller of the propeller 3 horizontally and then rotate the propeller until there is no misalignment.

[0036] The predetermined length is the length of the cable 5 (the cable 5 between the buoy and the sensor or between the sensors) when the cable 5 is hung vertically to the original second depth, and the excess cable 5 refers to the portion of the cable 5 that exceeds the predetermined length. The control unit 72 is capable of acquiring the length of the cable 5 being unwound by the winding machine 2 from the winding machine 2.

[0037] Furthermore, if the acquired first depth is deeper than the second depth, the control unit 72 sends an instruction to the winding machine 2 to wind the cable 5. For example, if the difference between the first depth and the second depth is X, the control unit 72 shortens the cable 5 in the winding unit 2 by X. This moves the sensor 1 connected via the cable 5 to its original second depth.

[0038] At this time, if the length of the cable 5 corresponding to the sensor 1 is longer than a predetermined length, the control unit 72 may wind up the excess cable 5 that has been unwound in preparation for the next alignment. For example, the control unit 72 may wind up the excess cable 5 with the winder 2 while propelling the propeller of the propeller 3 horizontally. If the sensor 1 or the control unit 72 can also detect the position of the sensor 1 in the horizontal direction and it is desired to align the sensor 1 horizontally with the upper and lower sensors, the control unit 72 may turn the neck of the propeller of the propeller 3 horizontally and then rotate the propeller until there is no misalignment.

[0039] After adjusting the depth of sensor 1 in this manner, the control unit 72 may again obtain the current first depth from sensor 1, compare it with the second depth in the memory unit 73, and perform a feedback process to readjust the depth if they are different.

[0040] In this embodiment, the control device 7 controls the winding machine 2 and the propeller 3 based on the first depth obtained from each sensor 1, adjusting each sensor 1 to be positioned at its original second depth, but the user may also directly operate the winding machine 2 and the propeller 3 remotely.

[0041] In this case, each sensor transmits its measured first depth and its sensor ID to a monitoring device (not shown) located on the ship or on land. The monitoring device displays the first depth and the sensor ID on an output device such as a display. The monitoring device may also display the original second depth corresponding to the sensor ID stored in a memory unit of the monitoring device on the display together with the first depth. The user may manually operate the reel 2 and the propeller 3 by referring to the first depth and second depth displayed on the display.

[0042] The underwater sensor system of this embodiment described above comprises a sensor 1 installed on a cable 5 and placed underwater, a winding machine 2 that adjusts the length of the cable 5, and a propeller 3 installed on the cable 5 and propelling the sensor 1 underwater via the cable 5.

[0043] As a result, in this embodiment, fluctuations in the depth of each sensor placed underwater can be suppressed, and the depth of each sensor can be kept constant.

[0044] The underwater sensor system of this embodiment may include a control device 7. The control device 7 includes an acquisition unit 71 that acquires, from the sensor 1 that is attached to the cable 5 and placed underwater, a first depth at which the sensor 1 is located, and a control unit 72 that, if the first depth is shallower than a second depth at which the sensor 1 should be located, sends an instruction to the winding machine 2 to unwind the cable 5 and sends an instruction to the propeller 3 to propel the sensor 1 in a deeper direction, and sends an instruction to the winding machine 2 to reel in the cable 5 if the first depth is deeper than the second depth.

[0045] This allows the distance between the sensors to be changed by controlling the reel 2 and the propeller 3 in conjunction with the current first depth measured by the sensor 1, thereby responding to changes in the water depth of the sensors due to the influence of ocean currents, etc. In other words, according to this embodiment, each sensor can observe environmental data such as water temperature at the same depth.

[0046] In addition, the underwater sensor system of this embodiment is equipped with a reeling machine 2, so that when the sea becomes rough due to a typhoon or the like, the cable between the buoy and the sensor or between the sensors can be reeled in and shortened to prevent the cable from becoming tangled.

[0047] The control device 7 described above can be, for example, a general-purpose computer system as shown in Fig. 5. The computer system shown in the figure includes a CPU (Central Processing Unit, processor) 901, a memory 902, a storage 903 (HDD: Hard Disk Drive, SSD: Solid State Drive), a communication device 904, an input device 905, and an output device 906. The memory 902 and the storage 903 are storage devices. In this computer system, the CPU 901 executes a predetermined program loaded on the memory 902, thereby realizing each function of the control device 7.

[0048] The control device 7 may be implemented by one computer or by multiple computers. The program of the control device 7 may be stored in a computer-readable recording medium such as a HDD, SSD, USB (Universal Serial Bus) memory, CD (Compact Disc), or DVD (Digital Versatile Disc), or may be distributed via a network. The computer-readable recording medium may be, for example, a non-transitory recording medium.

[0049] The present disclosure is not limited to the above-described embodiments, and various modifications are possible within the scope of the present disclosure.

[0050] 1, 1-1, 1-2: Sensor 2, 2-1, 2-2: Winding machine 3, 3-1, 3-2: Propulsion device 5: Cable 6: Buoy 7: Control device 71: Acquisition unit 72: Control unit 73: Storage unit

Claims

1. An underwater sensor system comprising: a sensor attached to a cable and disposed underwater; a winding machine for adjusting the length of the cable; and a propeller attached to the cable and propelling the sensor underwater via the cable.

2. The underwater sensor system according to claim 1, wherein the propulsion device generates a propulsive force so that the depth in water at which the sensor is located becomes the depth at which the sensor should be located.

3. The underwater sensor system according to claim 1, wherein a plurality of said sensors are attached to the cable, each sensor being positioned corresponding to a plurality of depths in the water, and the reel and the propeller are positioned between two adjacent sensors via the cable.

4. The underwater sensor system of claim 1, wherein the sensor measures a first depth underwater at which the sensor is located, and if the first depth is shallower than a second depth at which the sensor should be located, the winder pulls out the cable and the thruster propels the sensor in a deeper direction, and if the first depth is deeper than the second depth, the winder winds up the cable.

5. The underwater sensor system of claim 1, wherein the sensor measures a first depth underwater at which the sensor is located and is equipped with a control device that controls the winding machine and the propeller, and the control device is equipped with: an acquisition unit that acquires the first depth from the sensor; and a control unit that, if the first depth is shallower than a second depth at which the sensor should be located, sends an instruction to the winding machine to pull out the cable and sends an instruction to the propeller to propel the sensor in a deeper direction, and, if the first depth is deeper than the second depth, sends an instruction to the winding machine to wind up the cable.

6. A control device comprising: an acquisition unit that acquires a first depth at which a sensor is located from the sensor attached to a cable and disposed underwater; and a control unit that, if the first depth is shallower than a second depth at which the sensor should be located, sends an instruction to the winding machine to pull out the cable and sends an instruction to the propeller to propel the sensor in a deeper direction, and, if the first depth is deeper than the second depth, sends an instruction to the winding machine to wind up the cable.

7. A control method performed by a control device, comprising: acquiring a first depth at which a sensor is located, from a sensor attached to a cable and placed underwater; if the first depth is shallower than a second depth at which the sensor should be located, sending an instruction to a winding machine to pull out the cable and sending an instruction to a propeller to propel the sensor in a deeper direction; and if the first depth is deeper than the second depth, sending an instruction to the winding machine to wind up the cable.

8. A program that causes a computer to function as: an acquisition unit that acquires a first depth at which a sensor is located from a sensor attached to a cable and positioned underwater; and a control unit that, if the first depth is shallower than a second depth at which the sensor should be located, sends an instruction to the winding machine to pull out the cable and sends an instruction to the propeller to propel the sensor in a deeper direction, and, if the first depth is deeper than the second depth, sends an instruction to the winding machine to wind up the cable.

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