Unmanned flight body

Abstract

To provide an unmanned flight body in which: a multicopter type excellent in operability is adopted; a flight range and a flight time can be elongated; small size and light weight thereof can be realized while securing mountability of other devices; and a large capacity of an imaging range of a camera can be secured.SOLUTION: An unmanned flight body comprises: a machine body 2; a pair of right and left front arms 3 which are symmetrically arranged at both sides of right and left sides of the machine body 2 and extend from the machine body 2 to a front side thereof with respect to a central axis of the machine body 2 in a front-back direction; a rear arm 4 which extends along the central axis of the machine body 2 from the machine body 2 to a rear side thereof; and rotors 12a, 12b, 12c, 13a, 13b, 13c which are respectively arranged at the pair of front arms 3 and at the rear arm 4. The unmanned flight body also includes: a hydrogen tank 5 which is disposed at an upper part of the machine body 2; a fuel battery 6 which is disposed at a lower part of the machine body 2; and a camera 52 which is disposed at a lower side of a front-end part of the machine body 2.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an unmanned aerial vehicle equipped with a fuel cell. [Background technology]

[0002] A drone is an unmanned aerial vehicle that can be remotely controlled and fly autonomously, and is also known as a UAV (Unmanned Aerial Vehicle) or UAS (Unmanned Aerial System). In recent years, drones have been applied to a variety of fields, including delivery services, spraying pesticides and fertilizers, disaster investigations, and news reporting. They are also used to patrol and inspect power transmission and distribution facilities, and rotary-wing (multicopter) aircraft are mainly used due to their ease of operation and portability.

[0003] These drones are powered by batteries, fuel cells, or engines, but there is a strong demand for longer-distance and longer-duration flights to further improve operational efficiency. In the case of commonly used battery-powered drones, increasing the number of batteries installed is one way to extend the flight distance and flight time, but the increased number of batteries increases the weight and size of the aircraft. For this reason, there is a limit to the extension of flight distance and flight time relative to the number of batteries installed.

[0004] Therefore, a configuration has been proposed in which a drone is provided with a propulsion rotor to achieve high flight speeds and long-distance flight (see Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-59385 Summary of the Invention [Problem to be solved by the invention]

[0006] However, while this configuration is effective when there is a lot of horizontal flying, it is not suitable when there is a lot of vertical flying, such as patrolling power lines mainly installed in mountainous areas.

[0007] There are also single-rotor helicopters and fixed-wing airplanes, but these are more difficult to operate. Engine-equipped aircraft allow for long-distance flights, but they are bulky and lack portability. Furthermore, engine maintenance requires specialized knowledge, meaning only certain personnel can operate them.

[0008] Furthermore, even if a multicopter type is adopted, as the number of arms increases, the number of rotors and other parts also increases, resulting in poor aerodynamic characteristics (as horizontal air separation becomes more likely), which has a greater impact on propulsion and buoyancy, affecting range and flight time. Furthermore, as the number of arms increases, the number of rotors also increases, making it difficult to secure space above and below the aircraft body that will not interfere with the rotors, which reduces the ease of mounting other equipment such as fuel cells. Therefore, if an attempt is made to secure space that will not interfere with the rotors, the aircraft body will have to become larger, which is an inconvenience. Furthermore, as the number of arms and rotors increases, when a camera is mounted, the rotors tend to get into the camera's imaging range (the rotors tend to interfere), which inconveniently limits the imaging range.

[0009] The present invention was made in consideration of the above circumstances, and its main objective is to provide an unmanned aerial vehicle that employs a multicopter type with good maneuverability, has a long flight range and flight time, is small and lightweight while ensuring the ability to mount other equipment, and can ensure a large camera shooting range. [Means for solving the problem]

[0010] In order to achieve the above object, the unmanned aerial vehicle according to the present invention comprises: The aircraft body and a pair of left and right front arms disposed symmetrically on both the left and right sides of the aircraft body with respect to a central axis of the aircraft body in a longitudinal direction, the front and rear arms extending forward from the aircraft body; a rear arm extending rearward from the aircraft body along the central axis of the aircraft body; a rotor provided on each of the pair of left and right front arms and the pair of left and right rear arms, A hydrogen tank for pressurizing and storing hydrogen gas is disposed on the upper part of the aircraft body, a fuel cell is disposed under the aircraft body to which hydrogen gas stored in the hydrogen tank is supplied; The camera is located below the front end of the main body of the aircraft.

[0011] Therefore, the unmanned aerial vehicle of the present invention is a multicopter (tricopter) that is lifted and propelled by rotors attached to three arms consisting of a pair of front arms and a rear arm, and therefore has superior maneuverability (vertical flight) compared to a single-rotor helicopter type or a fixed-wing airplane type (improved maneuverability).

[0012] In addition, the aircraft body is equipped with a hydrogen tank and a fuel cell that supplies the hydrogen gas stored in this hydrogen tank, making it possible to significantly extend the range and flight time compared to unmanned aerial vehicles that are equipped with batteries (extended range and flight time).

[0013] Furthermore, because it is a tricopter, it is possible to secure a larger space in the center of the top and bottom of the aircraft body where the rotors of each arm do not interfere with each other compared to a quadcopter, which improves the ease of mounting hydrogen tanks and fuel cells. This makes it easier to mount hydrogen tanks and fuel cells according to the required cruising distance and duration (ensuring mountability).

[0014] Furthermore, even when hydrogen tanks and fuel cells are installed on the aircraft body, the length of each arm can be shortened to the extent that the rotors do not interfere with each other, making it easier to miniaturize the unmanned aerial vehicle. Moreover, since the number of arms and rotors can be reduced compared to a quad-core, it is also easier to achieve weight reduction. This makes it possible to further extend the flight distance and flight time (reducing the size and weight of unmanned aerial vehicles).

[0015] Furthermore, because a tricopter is used, it is possible to ensure a large gap between the rotors of the pair of front arms. Therefore, a large space is formed between the pair of front arms that does not interfere with the rotors. Therefore, by placing a camera below the front end of the aircraft body, it is possible to ensure a wide field of view not only below but also above the aircraft body as seen from the camera. Therefore, by remotely controlling the camera's shooting direction, it is possible to photograph subjects below the aircraft body (e.g., the base of a steel tower) and subjects above the aircraft body (e.g., the mounting portion of an insulator) in a single flight (improving the degree of freedom in photography).

[0016] Furthermore, since the hydrogen tank is located on top of the aircraft body and the fuel cell is located on the bottom, in the unlikely event that the unmanned aircraft crashes, the aircraft body and fuel cell will function as a crash zone, reducing the risk of the hydrogen tank being damaged and the flammable fluid (hydrogen gas) leaking (improved safety).

[0017] Here, when support legs are provided on each of the pair of left and right front arms and the rear arm, the fuel cell is preferably positioned between the support legs of the front arms and the support legs of the rear arms when viewed from the side, and the camera is preferably positioned forward of the fuel cell. Even when support legs are provided on each arm, a large space can be secured between each support leg, allowing the fuel cell to be installed without interfering with the legs. Also, since the camera can be positioned in front of the fuel cell at the same height as the fuel cell, the camera can be installed on the vehicle body without interfering with the fuel cell. This eliminates the need to install the camera below the fuel cell, allowing the length of the support legs to be reduced and making it possible to maintain a stable posture even when the vehicle body is supported by the support legs.

[0018] In the above configuration, if the hydrogen tank is cylindrical and the fuel cell is rectangular, the hydrogen tank should be positioned so that its axial direction is aligned with the central axis of the aircraft body in the fore-and-aft direction, and the fuel cell should be positioned so that its longitudinal direction is aligned with a direction perpendicular to the central axis of the aircraft body in the fore-and-aft direction.

[0019] With this configuration, even when a tricopter is used, it becomes easy to install a typical cylindrical hydrogen tank and a rectangular fuel cell. Furthermore, it becomes easier to adjust the center of gravity of the unmanned aerial vehicle (it becomes easier to balance the weight) if the axial direction of the fuel cell and the longitudinal direction of the hydrogen tank are perpendicular to each other rather than in the same direction. Therefore, even if the tank capacity (tank size) is different, in order to adjust the center of gravity, it is advisable to make the position of the hydrogen tank placed on top of the aircraft body adjustable in the fore-and-aft direction of the aircraft body.

[0020] Furthermore, the levitation rotor is preferably a coaxial counter-rotating rotor. Such a configuration makes it possible to increase the levitation capability and also ensure flight conditions even if one of the rotors fails (redundancy).

[0021] The aircraft body is constructed by fixing an upper base plate and a lower base plate at a predetermined distance in the vertical direction, and the hydrogen tank is fixed to the upper side of the upper base plate via a tank support base, and the fuel cell is fixed to the lower side of the lower base plate via a bracket. With this configuration, the tank and the fuel cell can be assembled using separate base plates, improving the ease of assembly of the unmanned aerial vehicle.In addition, since the hydrogen tank and fuel cell are arranged via base plates that face each other at a specified distance, the gap between them makes it easier for the aircraft body, which has a gap, to absorb impact in the event of a crash.

[0022] Here, various equipment can be placed between the upper and lower base plates, and the base ends of the front and rear arms can be inserted and fixed in place. By storing the base ends of the various equipment and arms between the upper and lower base plates in this way, it is possible to protect them without exposing them, and the base ends of the various equipment and arms placed between the upper and lower base plates can more easily absorb impacts in the event of a fall.

[0023] If the unmanned aerial vehicle is equipped with a cooling fan for cooling the fuel cell, the cooling fan for the fuel cell is preferably installed on the underside of the fuel cell facing downward. It is thought that when a fuel cell is exposed to wind from the front via a cooling fan during flight, the surface of the power generation cells tends to dry out, resulting in a decrease in power generation efficiency. Therefore, by placing the cooling fan on the underside of the fuel cell to prevent this, it is possible to avoid a decrease in power generation efficiency.

[0024] The pair of front arms may be foldable along the rear arms. This configuration makes it easier to load the device onto a vehicle, thereby increasing portability (portability). [Effects of the Invention]

[0025] As described above, the unmanned aerial vehicle of the present invention is equipped with a pair of left and right front arms extending forward from the aircraft body and a rear arm extending rearward from the aircraft body relative to the central axis of the aircraft body in the fore-and-aft direction, and each arm is equipped with a rotor, a hydrogen tank is arranged on the top of the aircraft body, a fuel cell is arranged on the bottom of the aircraft body, and a camera is arranged below the front end of the aircraft body.This makes it possible to obtain an unmanned aerial vehicle with good maneuverability that is suitable for vertical flight, has a long range and flight time, and is easy to make small and lightweight. [Brief explanation of the drawings]

[0026] [Figure 1] 1 is a perspective view of the overall configuration of an unmanned aerial vehicle according to the present invention, viewed obliquely from above. [Figure 2] 1 is a perspective view of the overall configuration of an unmanned aerial vehicle according to the present invention, viewed from above and in front. [Figure 3] FIG. 1(a) is a diagram illustrating the components attached to the upper base plate of the unmanned aerial vehicle according to the present invention, and FIG. 1(b) is a perspective view showing the tank support base. [Figure 4] FIG. 1 is a front view of an unmanned aerial vehicle according to the present invention. [Figure 5] FIG. 2 is a rear view of the unmanned aerial vehicle according to the present invention. [Figure 6] FIG. 1 is a plan view of an unmanned aerial vehicle according to the present invention. [Figure 7] FIG. 2 is a bottom view of the unmanned aerial vehicle according to the present invention. [Figure 8] FIG. 2 is a left side view of the unmanned aerial vehicle according to the present invention. [Figure 9] FIG. 2 is a right side view of the unmanned aerial vehicle according to the present invention. [Figure 10] FIG. 1( a ) is an explanatory diagram illustrating an area where the rotors of a quadcopter do not interfere, and FIG. 1( b ) is an explanatory diagram illustrating an area where the rotors of a tricopter do not interfere. DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0028] 1 to 2 and 4 to 9 show the schematic configuration of an unmanned aerial vehicle 1 according to the present invention. The unmanned aerial vehicle 1 has an airframe body 2, a front arm 3, a rear arm 4, a hydrogen tank 5, a fuel cell 6, and a camera 52.

[0029] The airframe body 2 has an upper base plate 21 and a lower base plate 22 arranged below the upper base plate. The upper base plate 21 and the lower base plate 22 have a plurality of ribs 23 arranged between their peripheries so as to form a predetermined gap between them, and are fixed to each other by screwing onto these ribs 23. Various equipment 11 such as a flight controller, motor control device, power distribution board, and electrical transmission device for the unmanned aerial vehicle 1 are fixed and mounted in the gap between the upper base plate 21 and the lower base plate 22 by appropriate means.

[0030] The front arms 3 are arranged in pair on both the left and right sides of the aircraft body 2 symmetrically with respect to the central axis of the aircraft body 2 in the longitudinal direction, and extend diagonally forward from the aircraft body 2 at a predetermined angle (for example, 60 degrees) with respect to the central axis. The rear arms 4 extend rearward from the aircraft body 2 along the central axis of the aircraft body 2.

[0031] The pair of front arms 31, 32 and the single rear arm 4 may be formed as members integral with the aircraft main body 2, but in this example they are formed from cylindrical members with their base ends fixed between the upper base plate 21 and the lower base plate 22. The base ends of the front arms 31, 32 and rear arm 4 are fixed via brackets 24 for fixing the arms, which are provided on the upper surface of the lower base plate 22. Furthermore, the front arm 3 and rear arm 4 may be provided horizontally, but in this example, they are provided so as to extend obliquely upward at a predetermined elevation angle relative to the horizontal plane.

[0032] A support leg 7 is fixed downward to each arm (front arm 3, rear arm 4) at a position equidistant from the center of gravity of the unmanned aerial vehicle 1. Each support leg 7 is composed of a rod-shaped leg member whose upper end is fixed via a bracket 8 to the middle of the respective arm 3, 4 and extends downward from there. Furthermore, the support leg 7 is arranged so that it tilts slightly toward the tip of each arm as it extends downward from the fixed position to the arms 3, 4 (position of the bracket 8). The length of the support leg 7 is set to a length that will prevent the fuel cell 6, which will be described later, from coming into contact with the landing surface of the unmanned aerial vehicle 1.

[0033] Rotors 12a, 13a, 12b, 13b, 12c, and 13c for levitation and propulsion, together with drive motors 14a, 14b, and 14c, are respectively provided at the upper ends of the pair of front arms 3 (31, 32) and rear arm 4. Each rotor has, for example, two blades and is configured as a coaxial counter-rotating rotor located above and below the drive motor.

[0034] The rotation axis of each of rotors 12a, 13a, 12b, 13b, 12c, and 13c is not vertical, but is attached with the upper side slightly tilted toward the aircraft body 2. Therefore, the rotation planes of each rotor are not in the same plane, but are tilted toward the aircraft body with respect to the horizontal plane. Each of rotors 12a, 13a, 12b, 13b, 12c, and 13c may be of a fixed pitch type or a variable pitch type. The centers (rotation axes) of the upper rotors 12a, 12b, and 12c are located at the vertices of a substantially equilateral triangle when viewed from above. Similarly, the centers (rotation axes) of the lower rotors 13a, 13b, and 13c are located at the vertices of a substantially equilateral triangle when viewed from above.

[0035] 3, a pair of tank supports 15, 16 that support the hydrogen tank 5 are arranged at a predetermined distance in the fore-and-aft direction of the aircraft body 2 on the upper surface of the upper base plate 21. Auxiliary plates 17, 18 are also arranged on both sides (outside) of the pair of tank supports 15, 16.

[0036] Tank supports 15, 16 are installed so as to be perpendicular to the central axis in the fore-and-aft direction of aircraft main body 2, and have tank holding portions 15a, 16a on their upper surfaces which have concave curved surfaces with a radius of curvature equal to or greater than the outer diameter of hydrogen tank 5, and have flat lower surfaces which abut against the upper base plate 21. Stepped holes 15b, 16b are formed near both ends of tank holding portions 15a, 16a, and tank supports 15, 16 are fixed to the upper surface of upper base plate 21 by screws inserted into these stepped holes 15b, 16b.

[0037] The auxiliary plates 17, 18 are arranged along the front-to-rear direction of the aircraft main body 2, extending from one side to the other side of the pair of tank support bases 15, 16. The auxiliary plates 17, 18 are provided with spare battery mounting sections 17a, 18a on which a substantially rectangular spare battery 19 is mounted, and belt mounting sections 17b, 18b, 17c, 18c on which holding belts 25, 26 for fastening the hydrogen tank 5 and spare battery 19 are attached.

[0038] The spare battery mounting sections 17a, 18a provided on each auxiliary plate 17, 18 are provided symmetrically on the left and right sides of the central axis of the aircraft main body 2 in the fore-and-aft direction (central axis of the hydrogen tank 5), and the belt mounting sections 17b, 18b, 17c, 18c are also provided symmetrically on the left and right sides of the central axis of the aircraft main body 2 (central axis of the hydrogen tank 5).

[0039] The hydrogen tank 5 is placed on the pair of tank support bases 15, 16 with shock absorbers 15c, 16c interposed therebetween. After adjusting the axial position of the central axis of the aircraft main body 2 (the central axis of the hydrogen tank 5), the hydrogen tank 5 is fixed onto the tank support bases 15, 16 by wrapping and tightening the holding belt 25 stretched between the belt mounting portions 17b of each auxiliary plate 17, 18. The axial position of this hydrogen tank 5 is adjusted so that the center of gravity of the entire unmanned aerial vehicle 1, including the fuel cell 6, camera 52, etc., is located on a vertical line passing through the approximate center of the three drive motors 14a, 14b, and 14c in a plan view. Therefore, the hydrogen tank 5 is located above the center of gravity of the unmanned aerial vehicle 1, with its axial direction aligned with the central axis of the aircraft body 2.

[0040] In addition, the spare battery 19 is placed on the spare battery mounting portions 17a, 18a of the respective auxiliary plates 17, 18, and then fixed onto the auxiliary plates 17, 18 by wrapping and tightening the holding belts 26 attached to the pair of belt mounting portions 17c, 18c provided on the respective auxiliary plates 17, 18.

[0041] The spare battery 19 is used to supply power for the initial operation of the fuel cell 6 and to supply power in an emergency when no output can be obtained from the fuel cell. Furthermore, a GNSS antenna 55 is provided on the upper base plate 21 located further outside the one auxiliary plate 17.

[0042] In addition, when viewed from above, a camera 52 is installed via a mounting bracket 51 on the lower front end of the main body 2 (lower base plate 22) at a position between the pair of left and right front arms 31, 32 and forward of the fuel cell. In this example, the mounting bracket 51 is fixed facing downward to the underside of the front end of the aircraft body 2 (lower base plate 22), and the camera 52 is attached to this mounting bracket 51 so that it can rotate around a vertical axis and around a horizontal axis, making it possible to adjust the shooting direction in all directions.

[0043] A fuel cell 6 is fixed below the lower base plate 22, i.e., below the center of gravity of the unmanned aerial vehicle 1. In this example, the fuel cell 6 is fixed by bolting a pair of left and right brackets 61 attached to the upper surface of the fuel cell 6 to the lower base plate 22 so that a gap is formed between the fuel cell 6 and the lower base plate 22. The fuel cell 6 is formed in a rectangular parallelepiped shape, and is attached so that its longitudinal direction is perpendicular to the central axis of the fuselage body 2 in the front-to-rear direction, and the plane of the fuel cell 6 faces up and down. In addition, the fuel cell 6 is disposed between the support legs 7 of the pair of left and right front arms 3 (31, 32) and the support legs 7 of the rear arm 4 in a side view. A cooling fan 62 for cooling the fuel cell 6 is provided on the underside of the fuel cell 6. This cooling fan 62 is positioned so that it is not directly exposed to wind when the unmanned aerial vehicle is flying horizontally, and in this example, it is directed downward so that air for cooling the battery is blown in an up and down direction.

[0044] A pressure reducing valve (not shown) is also mounted between the hydrogen tank 5 and the fuel cell 6 to reduce the pressure of the high-pressure hydrogen gas in the hydrogen tank 5 and supply it to the fuel cell 6. This pressure reducing valve is directly connected to the hydrogen tank 5 and may be either an integral type with the hydrogen tank or a separate type from the hydrogen tank.

[0045] In the above configuration, the unmanned aerial vehicle 1 is a tricopter equipped with a pair of front arms 3 (31, 32) and one rear arm 4 on the aircraft body 2, a hydrogen tank 5 is arranged above the aircraft body 2 above the center of gravity of the unmanned aerial vehicle 1, a fuel cell 6 to which hydrogen gas is supplied from the hydrogen tank 5 is arranged below the aircraft body 2 below the center of gravity of the unmanned aerial vehicle 1, and a camera is arranged below the front end of the aircraft body, which has the following various advantages.

[0046] (Ensuring operability) The unmanned aerial vehicle is a multicopter (tricopter) that is lifted and propelled by rotors attached to three arms consisting of a pair of front and rear arms. This makes it more suitable for vertical flight and easier to maneuver than single-rotor helicopters or fixed-wing airplanes. (Extended range and duration) The aircraft body 2 is provided with a hydrogen tank 5 and a fuel cell 6 to which hydrogen gas stored in the hydrogen tank is supplied, so that the flying distance and flying time can be significantly extended compared with unmanned flying vehicles equipped with a battery. In particular, tricopters have superior aerodynamic characteristics (less horizontal air separation) compared to quadcopters, making it easier to generate thrust and buoyancy, which makes it easier to extend their flight range and duration. (Small and lightweight) In this embodiment, which employs a tricopter, it is possible to reduce the number of arms and rotors compared to a quadcopter, which allows for a reduction in the number of parts and facilitates weight reduction. Furthermore, weight reduction also reduces the required buoyancy, making it possible to reduce the rotor diameter. This makes it easier to miniaturize the unmanned aerial vehicle. As described above, this embodiment is configured to facilitate miniaturization and weight reduction, which further facilitates extending the flight distance and flight time.

[0047] (Hydrogen tank and fuel cell installation) In a tricopter, it is easier to secure space between the three arms (space near the center of the aircraft body), making it easier to mount a hydrogen tank 5 and fuel cell 6 without interfering with the rotor. Compared to a quadcopter equipped with a hydrogen tank and a fuel cell, even if the weight and size of the hydrogen tank and fuel cell are the same, the quadcopter has four arms and an increased number of motors, rotors, and other parts, resulting in a larger and heavier unmanned aerial vehicle. Therefore, to obtain the necessary buoyancy, the diameter of the rotor 12 must be increased, as shown in Figure 10(a). Therefore, when attempting to reduce the size, the area S where the rotor 12 does not interfere becomes smaller, reducing the degree of freedom in arranging the equipment (fuel cell 6) and limiting the size of the equipment that can be carried (the size of the fuel cell 6, etc.). In contrast, in a tricopter, the number of arms, motors, and rotors is reduced, so the weight of the unmanned aerial vehicle 1 is relatively light and the required buoyancy is also relatively small, making it possible to reduce the diameter of the rotor 12, as shown in Figure 10(b).As a result, the area S where the rotor 12 does not interfere is wider, which increases the degree of freedom in arranging the equipment (fuel cell 6) and makes it possible to install relatively large equipment (such as a large fuel cell 6).

[0048] Another feature of the unmanned aerial vehicle 1 is that the hydrogen tank 5 is disposed above the center of gravity of the main body 2 along the longitudinal central axis (the axial direction of the hydrogen tank 5 is disposed parallel to the longitudinal central axis of the main body 2), whereas the fuel cell is disposed below the center of gravity of the main body 2 with its longitudinal direction perpendicular to the longitudinal central axis of the main body 2. This is because if the longitudinal direction of the fuel cell 6 were disposed along the longitudinal central axis of the main body 2, it would be difficult to install the camera 52 below the front end of the main body 2. Furthermore, if the axial direction of the hydrogen tank 5 and the longitudinal direction of the fuel cell 6 were not perpendicular, the dynamic inertia (roll and pitch moments) would not be aligned, resulting in unstable flight balance. Therefore, by orthogonally orthogonally orthogonally orthogonally orthogonally orthogonalizing the axial direction of the hydrogen tank 5 and the longitudinal direction of the fuel cell 6, as in this embodiment, it is possible to improve flight balance and also to easily adjust the center of gravity of the unmanned aerial vehicle 1. In particular, the axial position of the hydrogen tank 5 when placed on the tank support base 15 can be adjusted, so the center of gravity of the unmanned aerial vehicle can be adjusted by adjusting the axial position of the hydrogen tank 5. Therefore, the center of gravity can be easily adjusted even if the capacity of the tank to be installed is changed. Furthermore, in the above embodiment, auxiliary plates 17, 18 for carrying spare batteries are provided separately on both sides of the hydrogen tank 5, so that space can be secured for installing the hydrogen tank 5 between the pair of auxiliary plates 17, 18 on the left and right, making it possible to lower the installation position of the hydrogen tank and thereby lower the center of gravity.

[0049] (Expanded camera coverage and reduced flight inspection time) In this embodiment, a tricopter is used, so a large distance can be secured between the rotors of the pair of front arms 3 (31, 32). Therefore, even if the camera is placed below the front end of the aircraft body, when capturing an image above the aircraft body 2, the propeller (rotor) is less likely to appear in the image, making it possible to secure a large field of view above.

[0050] In unmanned aerial vehicles with four or more rotors (e.g., quatcopters (four rotors), hexacopters (five rotors), octocopters (eight rotors), etc.), when attempting to photograph the upper area from a camera installed on the aircraft itself, the rotors tend to interfere with the photographing range as the number of rotors increases, limiting the photographing range to the area below the aircraft itself. To avoid this, it is possible to provide a mount kit that allows a camera to be mounted on the top of the aircraft itself, but in this case, photographing the area below the aircraft itself becomes difficult for the same reason. For this reason, it is not possible to meet the need to photograph both the upper and lower areas in a single flight when inspecting power transmission equipment. In contrast to this, in this embodiment employing a tricopter, even if the camera is installed below the airframe body, when looking upward from the installation location, a large shooting range of the camera 52 can be secured between the pair of front arms without interfering with the rotor (a wide field of view can be secured not only below but also above the airframe body 2 as seen from the camera 52). Therefore, by remotely changing the shooting direction of the camera 52, it is possible to photograph an object below the airframe body (for example, the base of a steel tower) and an object above the airframe body (for example, the mounting portion of an insulator) in a single flight, thereby shortening the flight inspection time.

[0051] (Redundancy (safety)) Because the rotors on each arm are coaxial contra-rotating rotors, it is possible to ensure redundancy, allowing the aircraft to land even if one rotor stops. Generally, an aircraft with six or more blades can cope with one blade stopping without having to turn upside down. In particular, unmanned aircraft 1 equipped with a hydrogen tank 5 and fuel cell 6 has a certain weight, so there is a strong demand for sufficient buoyancy to ensure safe flight. Therefore, safety (redundancy) is ensured by using coaxial contra-rotating rotors for the rotors on each arm of the tricopter. In addition, in a tricopter, the counter torque of the rotors may not be fully offset, causing the machine body to rotate, but since each rotor is a contra-rotating rotor, it is possible to offset the counter torque.

[0052] (Hydrogen tank protection measures) This unmanned aerial vehicle 1 has the hydrogen tank 5 located on top of the main body 2 of the aircraft and the fuel cell 6 located on the bottom of the main body 2 of the aircraft. Therefore, even if the unmanned aerial vehicle were to fall, the main body 2 of the aircraft and the fuel cell 6 below the hydrogen tank 5 would form a crash zone, making it easy to protect the hydrogen tank 5. Moreover, the aircraft body 2 is composed of an upper base plate 21 and a lower base plate 22 that are fixed at a distance from each other, so the aircraft body with a gap between them makes it easier to absorb the impact of a crash. Also, various components 11 are arranged between the upper base plate 21 and the lower base plate 22, and the base ends of the pair of front arms 3 (31, 32) and the rear arm 4 are also inserted and fixed therein, so the hydrogen tank 5 is also protected by the base ends of the arms.

[0053] (Avoiding a decrease in power generation efficiency) In the above-described embodiment, the cooling fan 62 for the fuel cell 6 is disposed below the fuel cell 6, facing downward. This makes it easier to discharge water from the cooling fan 62, and also eliminates the problem of the cell surface that generates power drying out easily when the fuel cell 6 is directly exposed to the fan wind from the front, making it possible to avoid a decrease in power generation efficiency.

[0054] In the above example, the unmanned aerial vehicle 1 is not provided with a housing (exterior), but as shown in Figures 8 and 9, it may be provided with a housing 100 that covers at least the aircraft body 2 and the hydrogen tank 5. If such a housing 100 is provided, the hydrogen tank 5 may be structured so that it is inserted into the housing 100 from the front, for example, and fixed in place. In addition, in order to protect the hydrogen tank 5, a tank protection material may be installed on the top and sides of the hydrogen tank 5.

[0055] In addition, in the above example, a pair of front arms 3 (31, 32) and a rear arm 4 are fixed to predetermined locations on the main body 2 of the aircraft, but the pair of front arms 3 (31, 32) may be made movable circumferentially around the main body 2 (the bracket 24 that fixes the front arms 3 may be movable circumferentially) and may be folded so as to be approximately parallel to the rear arm 4. With this configuration, even if the aircraft body 2 is large, it can be transported by vehicle by folding the pair of front arms 3 (31, 32) along with the rear arm 4, ensuring portability. Furthermore, adopting a folding system allows for earlier preparation for flight compared to when the arms are detachable. [Explanation of symbols]

[0056] 1. Unmanned aerial vehicles 2. Aircraft body 3, 31, 32 Front arm 4 rear arm 5 Hydrogen Tank 6 fuel cell 12a, 12b, 12c, 13a, 13b, 13c rotors 52 Camera 62 Cooling fan

Claims

1. The aircraft body and a pair of left and right front arms disposed symmetrically on both the left and right sides of the aircraft body with respect to a central axis of the aircraft body in a longitudinal direction, the front arms extending forward from the aircraft body; a rear arm extending rearward from the aircraft body along the central axis of the aircraft body; a rotor provided on each of the pair of left and right front arms and the pair of left and right rear arms, A hydrogen tank for pressurizing and storing hydrogen gas is disposed on the upper part of the aircraft body, a fuel cell is disposed under the aircraft body to which hydrogen gas stored in the hydrogen tank is supplied; An unmanned aerial vehicle characterized in that a camera is located below the front end of the aircraft body.

2. The unmanned aerial vehicle described in claim 1, characterized in that each of the pair of left and right front arms and rear arms is provided with a support leg, the fuel cell is positioned between the support leg of the front arm and the support leg of the rear arm in a side view, and the camera is positioned forward of the fuel cell.

3. the hydrogen tank is cylindrical, and the fuel cell is rectangular; the hydrogen tank is arranged so that its axial direction is aligned with the central axis of the aircraft body in the front-to-rear direction, 3. The unmanned aerial vehicle according to claim 2, wherein the fuel cell is arranged so that its longitudinal direction is perpendicular to the central axis of the vehicle body in the longitudinal direction.

4. 4. The unmanned aerial vehicle according to claim 3, wherein the position of the hydrogen tank disposed on the upper part of the aircraft body is adjustable in the fore-and-aft direction of the aircraft body.

5. 2. The unmanned aerial vehicle according to claim 1, wherein the rotor is a coaxial counter-rotating rotor.

6. The machine body is configured by fixing an upper base plate and a lower base plate at a predetermined interval in the vertical direction, the hydrogen tank is fixed to the upper side of the upper base plate via a tank support base; 2. The unmanned aerial vehicle according to claim 1, wherein the fuel cell is fixed to the underside of the lower base plate via a bracket.

7. An unmanned aerial vehicle as described in claim 6, characterized in that various equipment is arranged between the upper base plate and the lower base plate, and the base end of the front arm and the base end of the rear arm are inserted and fixed between them.

8. a cooling fan for cooling the fuel cell; 2. The unmanned aerial vehicle according to claim 1, wherein the cooling fan is installed on the underside of the fuel cell and faces downward.

9. 2. The unmanned aerial vehicle according to claim 1, wherein the pair of left and right front arms are foldable along the rear arms.

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