Unmanned aircraft and its float

Abstract

To provide an autonomously flying unmanned aircraft freely landing on and leaving the water and its floats that can realize acoustic positioning by SBL by dispersively arranging a plurality of hydrophones in a limited space of the unmanned aircraft.SOLUTION: Lower portions of six arms 11 extending radially from a fuselage of a water-air combination drone 1 are respectively provided with float parts 14 via connectors 16. The float parts 14 sink under the water surface when the water-air combination drone 1 lands on the water surface to generate buoyancy in the water-air combination drone 1 so that the water-air combination drone 1 stays on the water surface. The float part 14 is composed of a columnar main body part 14a and a cap-like or conical projection part 14b extended downward from the main body part, and a hydrophone 20 is mounted inside the projection part 14b. The hydrophone 20 is fixed at a position and in such a posture that a pressure sensor 20a attached to an end portion of the hydrophone 20 can detect a sound wave in the water when the aerial combination drone 1 / aerial drone 1A lands on the water.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an autonomous flying unmanned aerial vehicle and its float, and particularly to an unmanned aerial vehicle that can autonomously fly and take off and land on water and its float.

Background Art

[0002] Patent Document 1 and Non-Patent Document 1 disclose a "water-air combined drone" in which an aerial drone flies while holding an underwater drone, separates and submerges the underwater drone after landing on the target water area, and recovers and takes off from the water after the work is completed, as shown in FIG. 7.

[0003] The underwater drone is equipped with a technology of "acoustic positioning" in which, after submerging in the target water area, it emits sound waves from a mounted transmitter, which are received by an underwater microphone (hydrophone) on the aerial drone side, automatically analyzed, and the position of the underwater drone is calculated.

[0004] As shown in FIG. 8, the calculated position information is sent to a land base together with the camera image of the aerial drone [FIG. 8(a)] or the camera image of the underwater drone [FIG. 8(b)], etc., and the position is displayed on the map. Non-Patent Document 2 discloses acoustic positioning technology.

[0005] The acoustic positioning technology of the conventional water-air combined drone adopts the SSBL (Super Short Base Line) method, in which three or more hydrophones are collectively housed in a cylindrical container, and the time difference of the acoustic signals received by each hydrophone is obtained to calculate the position of the transmission source.

[0006] Separately from this, an acoustic positioning method called SBL (Short Base Line) is disclosed in Non-Patent Document 2. In SBL, although it is necessary to arrange three or more hydrophones at intervals, positioning with higher accuracy than SSBL is possible.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Non-Patent Document

[0008]

Non-Patent Document 1

Non-Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0009] For an aerial drone designed to be able to land and take off from water, especially an amphibious drone, it has been difficult to secure enough space to disperse and arrange a plurality of hydrophones at a certain distance. Therefore, it has been necessary to adopt the SSBL method in which a plurality of hydrophones are arranged together in one place.

[0010] An object of the present invention is to solve the above technical problems and provide an unmanned aerial vehicle and its float that can realize acoustic positioning by SBL by dispersing and arranging a plurality of hydrophones in a limited space of an unmanned aerial vehicle that can autonomously fly freely in and out of water.

Means for Solving the Problems

[0011] In order to achieve the above object, the present invention is characterized in that an unmanned aerial vehicle that can autonomously fly freely in and out of water has the following configuration.

[0012] (1) At least three float parts that generate buoyancy for the aircraft during water landing are arranged horizontally and dispersedly, and a hydrophone is installed in each float part such that its pressure-sensitive part is exposed to underwater sound waves during water landing.

[0013] (2) The relative positions between the fuselage part of the unmanned aircraft and each float part are made variable by remote control.

[0014] (3) In a float for an unmanned aircraft that generates buoyancy for the unmanned aircraft during water landing, a hydrophone is installed in the float part such that its pressure-sensitive part is exposed to underwater sound waves during water landing.

Advantages of the Invention

[0015] According to the present invention, the following effects can be achieved.

[0016] (1) Since a hydrophone is provided in the dead space inside the floats that are horizontally dispersed and spaced apart in the water-air hybrid drone / aerial drone, accurate acoustic positioning by the SBL method can be realized without separately securing a space for arranging a plurality of hydrophones apart from each other.

[0017] (2) By making the connecting tools between each float part and the arm and the arm itself have a telescopic structure so that the relative positions between the floats (each hydrophone) can be arbitrarily adjusted, stable flight and high-precision acoustic positioning of the water-air hybrid drone / aerial drone can be realized even in rough weather.

[0018] (3) Since a hydrophone is installed in the float for the unmanned aircraft such that its pressure-sensitive part is exposed to underwater sound waves during water landing, accurate acoustic positioning by the SBL method can be realized by replacing it with an existing float.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Mode for Carrying Out the Invention

[0020] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view of a water-air combined drone 1 according to an embodiment of the present invention, and FIG. 2 is its front view [FIG. (a)] and top view [FIG. (b)].

[0021] The water-air combined drone 1 is composed of an aerial drone 1A and an underwater drone 1B. The underwater drone 1B is stored in a storage gauge 10 provided below the fuselage of the aerial drone 1A. The aerial drone 1A and the underwater drone 1B are connected via a sufficiently long signal cable (not shown).

[0022] After the water-air combined drone 1 lands on the target water area, the underwater drone 1B starts and dives underwater from the storage gauge 10, and is recovered into the storage gauge 10 again by winding up the signal cable with a winch 15 after the work is completed.

[0023] The aerial drone 1A is equipped with six arms 11 extending radially from its fuselage portion, and a rotor 12 and its driving motor 13 are provided at the tip of each arm 11. At the lower part of each arm 11, a float portion 14 for generating buoyancy for the hydro-aerodynamic drone 1 / aerial drone 1A to sink below the water surface when landing on the water and stay on the water surface is provided via a connecting tool 16, respectively.

[0024] Figure 3 is a diagram showing the cross-sectional structure of the float portion 14. The float portion 14 is composed of a cylindrical main body portion 14a and a cap-shaped or conical protrusion portion 14b extending downward therefrom, and a hydrophone 20 is mounted inside the protrusion portion 14b.

[0025] The hydrophone 20 is fixed in a position and posture where a pressure-sensitive element 20a attached to its end can detect underwater sound waves when the hydro-aerodynamic drone 1 / aerial drone 1A lands on the water. In this embodiment, the pressure-sensitive element 20a is fixed in a position and posture where it is exposed underwater from the tip of the protrusion portion 14b. The pressure-sensitive element 20a does not necessarily need to be directly exposed underwater, and as shown in Figure 4, it may be indirectly exposed to underwater sound waves via a buffer resin or the like.

[0026] In this embodiment, hydrophones 20 are provided in all six float portions 14. However, when the float portions 14 are provided at four or more locations, hydrophones 20 may be provided in at least three or more of them, which are a part thereof. In that case, if the float portions 14 are provided at six locations on the circumference, for example, it is desirable to mount the hydrophones 20 every other one so that the distance between each hydrophone 20 becomes longer.

[0027] Also, a hydrophone for SSBL may be provided separately so that the SBL method and the SSBL method can be used in combination or selectively.

[0028] On the one hand, in this embodiment, by providing the hydrophones 20 inside the plurality of float portions 14, it becomes possible to vary the relative positions between the aerial drone 1A and the respective hydrophones 20 (float portions 14). As a result, accurate acoustic positioning can be achieved even in adverse environments such as high waves or strong winds.

[0029] For example, if each arm 11 has a telescopic structure and its length can be adjusted remotely, as shown in FIG. 5, in strong winds, the influence of the wind can be suppressed by flying with the arm 11 retracted, while after landing on the water, the influence of the wave height can be suppressed by extending the arm 11 to stabilize the posture of the aerial drone 1A, and high-precision SBL positioning can be achieved. However, when the arm 11 has a telescopic structure, the amount of expansion and contraction affects the positioning result, so it is desirable to grasp the amount of expansion and contraction and reflect it in the positioning calculation.

[0030] Furthermore, if the connecting tool 16 between each float portion 14 and the arm 11 has a vertically telescopic structure and its length can be adjusted remotely, as shown in FIG. 6, during flight, the air resistance can be suppressed by retracting the connecting tool 16, while after landing on the water, the influence of the wave height can be suppressed by extending the connecting tool 16 to stabilize the posture of the aerial drone 1A, and high-precision SBL positioning can be achieved.

[0031] According to this embodiment, in the water-air combined drone 1 / aerial drone 1A, since the hydrophone 20 is provided in the dead space inside the floats 14 that are horizontally dispersed and spaced apart, accurate acoustic positioning by the SBL method can be achieved without separately securing a space for arranging the plurality of hydrophones 20 apart from each other.

[0032] Also, if the relative positions between the aerial drone 1A and each float portion 14 can be arbitrarily adjusted by making the connecting tool 16 between each float portion 14 and the arm 11 and the arm 11 itself have a telescopic structure, stable flight and high-precision acoustic positioning of the water-air combined drone 1 / aerial drone 1A can be achieved even in rough weather.

[0033] In the above-described embodiment, the present invention has been described by taking the water-air combined drone 1 as an example. However, the present invention is not limited to this, and it can be similarly applied to various unmanned aircraft other than drones that can autonomously fly with the ability to land and take off from water, such as helicopters and multicopters, for detecting acoustic signals emitted by fingers or transponders of independent underwater vehicles and positioning their locations.

[0034] Furthermore, in the above-described embodiment, the present invention has been described by taking the water-air combined drone 1 with each float unit 14 pre-mounted as an example. However, the present invention is not limited to this, and it can also be realized as a float for an unmanned aircraft that can autonomously fly with the ability to land and take off from water.

[0035] Furthermore, in the above-described embodiment, a total of six hydrophones 20 are provided in each of the six float units 14. However, it is not necessary to always operate all the hydrophones 20 for positioning. When four or more hydrophones 20 are provided, in an environment where power saving is required, an environment where high-precision positioning is not required, or an environment where the distance from the underwater drone is short, etc., only at least three of the hydrophones 20 can be selectively operated.

[0036] According to the above-described embodiment, accurate acoustic positioning by the SBL method can be realized in the water-air combined drone 1 / aerial drone 1A. Also, by making it possible to arbitrarily adjust the relative positions of the aerial drone 1A and each float unit 14, stable flight and high-precision acoustic positioning can be realized even in rough weather. Therefore, it becomes possible to contribute to Goal 9, "Build resilient infrastructure, promote inclusive and sustainable industrialization," and Goal 11, "Make cities inclusive, safe, resilient and sustainable," of the Sustainable Development Goals (SDGs) led by the United Nations.

Explanation of Reference Numerals

[0037] 1…Water-air combined drone, 1A…Aerial drone, 1B…Underwater drone, 10…Storage gauge, 11…Arm, 12…Rotary wing, 13…Drive motor, 14…Float section, 15…Winch, 16…Connector, 20…Hydrophone, 20a…Pressure-sensitive part

Claims

1. In an unmanned aircraft that can autonomously fly while being able to land on water and take off from water, at least three float parts that generate buoyancy for the aircraft during landing are horizontally dispersed and equipped, hydrophones are respectively installed in each float part such that their pressure-sensitive parts are exposed to underwater sound waves during landing, An unmanned aircraft characterized by performing positioning in the SBL method based on acoustic signals detected by at least three hydrophones respectively installed in each of the above float parts.

2. The unmanned aircraft according to Claim 1, characterized in that the unmanned aircraft is a hydro-air combined drone, and the at least three float parts are equipped on the aerial drone.

3. The unmanned aircraft according to Claim 1, characterized in that float parts in which hydrophones are installed are equipped at at least four locations, and means for selectively operating at least three of the at least four hydrophones is provided.

4. The unmanned aircraft according to Claim 1, characterized in that the relative positions of the fuselage part of the unmanned aircraft and each float part are variable by remote control.

5. Each of the above float parts is provided below an arm part extending radially from the fuselage part of the aircraft, The unmanned aircraft according to Claim 4, characterized in that the arm part is extendable by remote control.

6. Each of the above float parts is provided via a coupler below an arm part extending radially from the fuselage part of the aircraft, The unmanned aircraft according to Claim 4, characterized in that the coupler is extendable in the vertical direction by remote control.

7. In a float for an unmanned aircraft that generates buoyancy for an unmanned aircraft when landing on water, at least three are horizontally dispersed and equipped, A float for an unmanned aircraft, characterized in that hydrophones that output acoustic signals used for positioning in the SBL method are respectively installed in each float part such that their pressure-sensitive parts are exposed to underwater sound waves during landing.

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