JP6675657B2 - Unmanned aerial vehicle - Google Patents

Description

  The present invention relates to unmanned aerial vehicle technology.

  Conventionally, a small unmanned aerial vehicle represented by an industrial unmanned helicopter is expensive and difficult to obtain, and requires skill in operation to stably fly. However, in recent years, sensors and software used for attitude control and autonomous flight of unmanned aerial vehicles have greatly improved, which has significantly improved the operability of unmanned aerial vehicles and made it possible to obtain high-performance aircraft at low cost. . Against this background, small multicopters are currently being applied to various missions in a wide range of industrial fields as well as for hobbies.

  Patent Literatures 1 and 2 disclose a multicopter including an arm or a frame that functions as a rotor guard by covering the entire length of the rotor.

U.S. Pat. No. 8,794,566 (B2) US Patent Application Publication No. 2016/229534 (A1)

  In a general multicopter, a structure in which a plurality of arms extend radially from the center of the fuselage and a rotor is disposed at the tip of each arm is often used. These arms and rotors occupy most of the horizontal dimension of the fuselage, which reduces the space efficiency during transportation and storage. In particular, in a configuration in which a large number of rotors are arranged on the same horizontal plane, it is necessary to lengthen the arms so that the propellers do not come into contact with each other, and the horizontal dimension of the body tends to increase. In addition, the rotor guard attached to the arm also reduces the space efficiency of the multicopter. In particular, when the entire length of the rotor is covered with an arm or a frame as in the multicopters of Patent Documents 1 and 2, the horizontal dimension of the fuselage significantly increases, and the problem of space efficiency becomes more serious. On the other hand, it is troublesome to remove the arm or the rotor guard or disassemble the airframe each time the multicopter is transported and stored, and may cause an assembly error during flight.

  In view of the above problems, an object of the present invention is to provide an unmanned aerial vehicle with good space efficiency and portability.

In order to solve the above problem, an unmanned aerial vehicle according to the present invention includes a rotor having horizontal rotors, and an arm that supports the rotor, and a tip of the arm extends in the same direction arranged vertically. Each of the rods supports a different one of the rotors, and the base end of the arm is formed of a single cylindrical rod; between the one rod between said two rods, connecting portions of the hollow bifurcated is provided toward the proximal side to the distal end side, in the interior of the connecting portion, wherein A drive circuit for a brushless motor of the rotor is housed therein.

  For example, in an unmanned aerial vehicle having a large number of rotors, such as an octa-copter, the rotor may be a contra-rotating propeller to reduce the number of arms in order to reduce the horizontal dimension of the fuselage. However, in the case where the rotors are arranged on the upper and lower surfaces of one arm, there is a problem that the thrust efficiency per rotor is reduced due to the short distance between the rotors. In the present invention, since the rotors arranged vertically are arranged on separate rods, the rotors can be arranged at a greater distance than when the rotors are arranged on the upper and lower surfaces of one arm. Further, compared to a configuration in which the same number of rotors as the rotor of the unmanned aerial vehicle of the present invention are arranged on the same horizontal plane, the number of arms when the body is viewed in plan can be reduced to half. This makes it possible to reduce the horizontal dimension of the airframe while reducing the reduction in the thrust efficiency of the rotor.

  Further, high-frequency noise generated by the drive circuit of the brushless motor may affect detection accuracy of other sensor components. By arranging the driving circuit in the connecting member, the driving circuit can be separated from the center of the body, and the influence of the noise of the driving circuit can be reduced.

  Further, it is preferable that the rotors supported by the respective rods are arranged such that their rotating surfaces face each other.

  Since the tip portion of the arm is constituted by two rods, the rotor is arranged on the inner surface of these two rods (the surface of the two rods facing each other). The rotors supported by the rods can be arranged such that their planes of rotation face each other. This creates a space on the outer surfaces of the two rods where other members and devices can be placed.

  At this time, one end of the rotor guard is connected to one of the two rods, and the other end of the rotor guard is connected to the other, and the rotor guard is arranged so as to vertically surround the horizontal rotor. Alternatively, the configuration may be as follows.

  The rotors supported by the two rods are arranged so that their rotating surfaces face each other, and the ends of the rotor guards are connected to these rods, so that the horizontal rotors of both rotors can be combined with one rotor guard. Can be vertically enclosed.

  Further, it is preferable that the rotor guard can be pivoted in a horizontal direction about a connection portion with the arm.

  By rotating the rotor guard in the horizontal direction and folding the rotor guard along the side surfaces of the arms (two rods), the horizontal dimension of the fuselage can be reduced without removing the rotor guard.

  At this time, the rotor guard is preferably an elongated linear frame, and a plurality of the rotor guards are preferably attached to the arm.

  By making the rotor guard an elongated linear frame, the weight of the rotor guard can be reduced. By providing each arm with a plurality of arms, it is possible to adjust the safety performance of the rotor guard according to the usage environment of the unmanned aerial vehicle. For example, if the purpose is only protection of propellers, it is sufficient to provide the most efficient number of rotor guards for the main shape of the surrounding objects, and to ensure the safety of pedestrians etc. in unexpected situations In this case, the number of rotor guards may be increased as appropriate so as to reduce the blind spot.

  Preferably, the arm is pivotable in a horizontal direction from a base end thereof.

  Since the arm can be folded in the horizontal direction, the unmanned aerial vehicle can be compactly transported and stored without removing the arm each time. In particular, if the rotor guard is also foldable, the trouble of removing the rotor guard can be saved. In particular, when the rotors are arranged with their rotating surfaces facing each other, the vertical dimension of the body after the arms are folded can also be kept small.

  At this time, it is preferable that the horizontal rotary wing is a foldable propeller that can be stored by bending the blade clockwise or counterclockwise.

  Further, the unmanned aerial vehicle of the present invention includes a plurality of the arms, a base end of each of the arms and a vicinity thereof are configured as a single rod, and the plurality of the arms are arranged in a same direction. It is preferable that the two rods of each arm have a positional relationship in which the base end of the other adjacent arm or the vicinity thereof can be accommodated between the two rods when folded horizontally.

  The base end of the arm is constituted by one rod, and when all the arms are folded, the base end of one adjacent arm fits between the two rods of the other arm. By arranging the arms, the body can be folded more compactly.

  As described above, according to the unmanned aerial vehicle of the present invention, space efficiency and portability of the airframe can be improved.

It is an external appearance perspective view which shows the state at the time of the flight of a multicopter. It is an external appearance perspective view which shows the state at the time of conveyance and storage of a multicopter. FIG. 3 is a side view of the unfolded arm and a side view of the folded arm. FIG. 4 is a plan view of the arm shown in FIGS. 3A and 3B. FIG. 3 is a side sectional view of FIG. FIG. 2 is a block diagram illustrating a functional configuration of the multicopter.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiment described below is an example of a multicopter 10 that is an unmanned aerial vehicle having a plurality of rotors. Note that “up”, “down”, and “vertical” in the following description are directions parallel to the Z axis of the coordinate axis display shown in FIGS. 1 and 2, and the Z1 side is the upper side. Further, “horizontal (direction)” refers to an XY plane (direction) in the same coordinate axis display. The “circumferential direction” of the multicopter 10 refers to a clockwise or counterclockwise direction when the multicopter 10 is viewed in plan.

[Aircraft Overview]
1 and 2 are perspective views showing the appearance of a multicopter 10 according to the present embodiment (hereinafter, also referred to as “present example”). FIG. 1 is a diagram showing a state of the multicopter 10 during flight. FIG. 2 is a diagram illustrating a state of the multicopter 10 during transportation and storage.

  The multicopter 10 includes a rotor R having a propeller 42 that is a horizontal rotor, and an arm 70 that supports the rotor R. The base end (root) of each arm 70 is fixed to a center frame which is a skeleton (not shown) covered by the shell cover 19. In this example, four arms 70 are connected to the center frame, and these arms 70 are arranged at equal intervals along the circumferential direction of the multicopter 10 and extend radially from the center of the fuselage.

  The distal end of each arm 70 is composed of two rods 72 and 73 that are arranged vertically and extend in the same direction. The two rods 72 and 73 respectively support different rotors R, and these rotors R are arranged so that their rotating surfaces face each other.

  At the tips of the rods 72, 73, two rotor guards 78, which are elongated linear frames, are provided. The rotor guard 78 has one end connected to the tip of the upper bar 72 and the other end connected to the tip of the lower bar 73, and is deployed so as to vertically surround the propeller 42.

  In addition to the arm 70, two batteries 60 and a laser scanner 90 are fixed to the center frame of this example. Further, inside the shell cover 19, a control device and a sensor component of the multicopter 10 are housed. Although the multicopter 10 of the present embodiment is an example of a body for surveying, it is equipped with the laser scanner 90, but the use of the unmanned aerial vehicle of the present invention is not particularly limited. That is, the laser scanner 90 may be omitted.

  As shown in FIG. 2, in the multicopter 10 of the present example, all of the arm 70, the rotor guard 78, and the propeller 42 are foldable. Can be reduced in horizontal dimension.

[Structure of arm]
Hereinafter, the structure of the arm 70 will be described with reference to FIGS. FIG. 3A is a side view of the deployed arm 70. FIG. 3B is a side view of the folded arm 70. FIG. 4 is a plan view of the arm 70 shown in FIGS. 3A and 3B. FIG. 5 is a side sectional view of FIG. In the following description, one of the four arms 70 of the multicopter 10 will be described as an example, but the structure of the other arms 70 will be described except for the types of sensors held in a sensor housing 749 described later. Also has the same basic structure. In the following description, the “proximal side” refers to the arrow b side in the direction parallel to the arrows depicted in FIGS. 3 to 5, and the “proximal end” is the proximal end. Say. Similarly, the “tip side” refers to the side indicated by the arrow t, and the “tip section” refers to the end on the tip side.

(Configuration overview)
The arm 70 of the present example has a trunk portion 70a, a joint portion 70b, and a fork portion 70c. The trunk portion 70 a is a portion constituted by a single rod 71 including the proximal end of the arm 70. The fork portion 70c is a portion including two rods 72, 73 arranged on the distal end side of the arm 70, and a connecting member 74 for coupling the rods 72, 73 and the rod 71. The joint part 70b is a connection part between the base part 70a and the fork part 70c, and is a joint part capable of bending the fork part 70c in the horizontal direction. Note that the basic portion 70a, the joint portion 70b, and the fork portion 70c are groupings for convenience, and it is not necessary to strictly separate their boundaries. The basic portion 70a is a portion fixed to the center frame, the fork portion 70c is a bifurcated portion, and the joint portion 70b is a joint portion.

(Core and joint)
The rod 71 constituting the main body 70a is a cylindrical pipe material made of CFRP (Carbon Fiber Reinforced Plastics). The rod 71 has a base end fixed to the above-mentioned center frame so as not to be movable, and a tip end thereof is connected to the connecting member 74 via an adapter member 741. In this example, the adapter member 741 and a backbone-side connecting portion 74a described later constitute a joint 70b.

(Fork part)
As described above, the fork portion 70c of the present example has the two rods 72 and 73 and the connecting member 74 that constitute the distal end of the arm 70.

  The connecting member 74, which is a part of the fork portion 70c, is a joint formed by assembling a flat plate made of CFRP and a plate-shaped member made of resin.

  The connecting member 74 has a trunk side connection part 74a and a branch side connection part 74b. The trunk side connection portion 74a is a portion to which the rod 71 is connected, and is configured by vertically arranging two flat plates made of CFRP with their plate surfaces facing up and down. The branch-side connecting portion 74b is a portion to which the rods 72 and 73 are connected, and is bifurcated vertically from the base end toward the distal end, and is formed in a substantially U-shape in side view. A flat plate made of CFRP is used on the side surface of the branch-side connection portion 74b, and a resin plate member is used on the upper and lower surfaces of the branch-side connection portion 74b. Adapter members 742 and 743 (see FIG. 5) to which the rods 72 and 73 are connected are fixed to the distal end of the branch-side connection portion 74b.

  A landing gear 79, which is a leg extending downward from the branch side connection portion 74b, is coupled to a side surface of the branch side connection portion 74b. The landing gear 79 is formed by assembling a flat plate made of CFRP into a square tube shape. At the lower end of the landing gear 79, a rubber contact block is provided to project below the other parts of the landing gear 79 to reduce the collision with the ground or the floor surface and prevent the landing gear 79 from being chipped or cracked. 791 are provided.

  The two rods 72, 73, which are part of the fork 70c, are rods extending in the same direction and arranged vertically one above the other, and are mainly made of CRFP cylindrical pipe material. A motor mount 76 which is a resin flat plate member connected to the pipe material by a clamp 761 is attached to the tip of the pipe material of each of the rods 72 and 73. The rotor R is fixed to the motor mount 76 with screws. The rods 72 and 73 of the fork 70c support different rotors R, respectively, and these rotors R are arranged so that their rotating surfaces face each other.

  In the multicopter 10 of the present embodiment, the rotors R arranged above and below are supported by separate rods 72, 73. Can be arranged at a distance from each other. Further, compared to a configuration in which the same number of rotors as the rotors R of the multicopter 10 are arranged on the same horizontal plane, the number of arms when the body is viewed in plan is reduced to half. This makes it possible to reduce the horizontal dimension of the multicopter 10 while reducing the reduction in thrust efficiency per rotor R.

  The above-described effect can be obtained even when the rotating surfaces of both rotors R supported by the rods 72 and 73 face upward. On the other hand, in this example, these rotors R are supported on the inner surfaces of the two rods 72 and 73 (the surfaces of the two rods 72 and 73 facing each other), and are arranged such that their rotating surfaces face each other. Thus, when the arm 70 is folded, the vertical dimension of the body can be suppressed to be small.

  Further, in the multicopter 10 of this example, when all the arms 70 are folded, the trunk 70a and the joint 70b (the trunk-side connection part 74a) of one of the arms 70 adjacent to each other are connected to the fork of the other arm 70. 70c (see FIG. 2)

  The base end portion of the arm 70 is configured as one rod body (base part 70a, base connection part 74a), and the two rods forming the fork part 70c of the adjacent arm 70 in the vertical direction. By making the positions different, interference between the folded arms 70 is prevented, and the body can be folded more compactly.

  As shown in FIG. 5, an ESC 411 (Electric) which is a drive circuit of a brushless motor 41 (hereinafter simply referred to as “motor 41”) of the rotor R is provided inside the branch-side connection portion 74b of the connecting member 74. Speed Controller). High frequency noise generated by the ESC 411 may affect the detection accuracy of other sensor components. By arranging the ESC 411 in the connecting member 74 as in the present example, the ESC 411 can be arranged at a position distant from the sensor component mounted on the center frame, and the influence of noise of the ESC 411 is reduced. .

  Further, a sensor housing 749 for holding the optical flow sensor 33 is integrally formed with a plate-like member constituting the lower surface of the branch-side connection portion 74b. In the multicopter 10 of the present example, the pair of arms 70 located at positions that are point-symmetric with respect to each other in the circumferential direction of the fuselage have an optical flow sensor 33 in the sensor housing 749 and a sensor housing 749 of the other pair of arms 70 The laser distance sensor 35 is held. Note that the type of the sensor housed in the sensor housing 749 is arbitrary and is not particularly limited. The upper and lower surfaces of the branch-side connection portion 74b of this example are plate members made of resin, and have a high degree of freedom in shape. By providing a sensor housing at an arbitrary position on the upper and lower surfaces of the branch-side connection portion 74b and arranging an arbitrary sensor there, the degree of freedom of the mounting position of the sensor is increased, and the possibility of function expansion using the sensor is possible. Is spread. Furthermore, what is provided on the upper and lower surfaces of the branch-side connection portion 74b is not limited to the sensor housing, and may be, for example, a connection portion of a parachute device.

  The same applies to the motor mount 76 which is a resin member. Of the upper and lower surfaces of the motor mount 76, the surface on the side opposite to the side supporting the rotor R can have any use.

  It should be noted that the multicopter 10 of this example obtains additional performance accompanying the connecting member 74 by using the connecting member 74 for the arm 70, but the connecting member 74 is an essential element of the unmanned aerial vehicle of the present invention. Instead, for example, the base ends of the two rods 72 and 73 may be directly fixed to the center frame.

(Rotor guard)
The rotor guard 78 is a frame formed by joining small diameter pipe members made of CFRP. A hub 789 that supports the rotor guard 78 is provided at the tip of each of the rods 72 and 73. The rotor guard 78 has one end connected to the upper rod 72 and the other end connected to the lower rod 73, and is deployed so as to vertically surround the rotor R (the propeller 42) of the rods 72, 73. Is done.

  In the multicopter 10 of the present example, the tip of the arm 70 is formed of two rods 72, 73, and the inner surfaces of the two rods 72, 73 (the two rods 72, 73). The rotors R are disposed on the surfaces facing each other). In addition, by connecting the ends of the rotor guard 78 to the rods 72 and 73, the propellers 42 of both rotors R can be vertically surrounded by one rotor guard 78.

  Each of the rotor guards 78 is rotatable about a hub 789 in the horizontal direction. When transporting and storing the multicopter 10, the rotor guard 78 can be compactly stored by folding the rotor guard 78 along the side surface of the fork portion 70c.

  Each arm 70 has two rotor guards 78. These rotor guards 78 can be expanded up to 135 ° when the arrangement angle when folded parallel to the side surface of the fork portion 70c is 0 °. When the rotor guard 78 is deployed at 135 °, the fixing piece 781 of the rotor guard 78 fits into a shaft (not shown) of the hub 789, and the position of the rotor guard 78 is fixed. The rods 72 and 73 are provided with clips 782 for holding the folded rotor guard 78.

  Note that the arm 70 of the present example has two rotor guards 78, but the number of the rotor guards 78 provided in one arm 70 is not limited to two, and depends on the use environment of the multicopter 10. It can be adjusted appropriately. For example, if only the protection of the propeller 42 is intended, the most efficient number of rotor guards 78 may be provided for the main shape of the surrounding object, and the security of the pedestrian or the like in an unexpected situation is ensured. For the purpose, the number of the rotor guards 78 may be increased as appropriate so as to reduce the blind spot.

  The rotor guard 78 of the present embodiment employs an elongated linear frame because it is lightweight and is suitable for folding, but the form of the rotor guard of the present invention is the same as that of the present embodiment. It is not limited to. The rotor guard of the present invention may be, for example, a wide removable rotor guard provided that the rotor R (the propeller 42) of the rods 72, 73 is vertically surrounded. Further, the rotor guard is not an essential element of the unmanned aerial vehicle of the present invention, and can be omitted if unnecessary.

  Then, as shown in FIG. 3 and the like, in the multicopter 10 of the present example, the two rods 72 and 73 supporting the rotor R are shorter than the diameter of the propeller 42. In the multicopter 10 of this example, the arm 70 is not provided with a function of protecting the rotor R, and the support of the rotor R and the protection of the rotor R are separated. This avoids an increase in the horizontal dimension of the fuselage, and can easily omit this when protection of the rotor R is not required.

(propeller)
The propeller 42 of the rotor R is a foldable propeller that can bend the blade clockwise or counterclockwise.

  As described above, in the multicopter 10 of the present example, the arm 70 is foldable in the horizontal direction, and the rotor guard 78 and the propeller 42 are also foldable. Thereby, when transporting and storing the multicopter 10, the space efficiency and portability of the arm 70 can be easily increased without removing the constituent members of the arm 70 at all.

  The folding structure of the arm 70, the rotor guard 78, and the propeller 42 is extremely significant in improving the space efficiency and portability of the multicopter 10, but these are selectable elements. It is also possible to omit any or all of the above.

[Function configuration]
FIG. 6 is a block diagram showing a functional configuration of the multicopter 10. The functions of the multicopter 10 include a flight controller FC as a control unit, a plurality of rotors R, an ESC 411 as a drive circuit of a brushless motor 41 constituting the rotor R, a communication device 52 for communicating with a pilot (operator terminal 51), It is composed of a laser scanner 90 which is an external device for surveying, and a battery 80 for supplying power thereto.

  The flight controller FC has a control device 20 which is a microcontroller. The control device 20 has a CPU 21 as a central processing unit, and a memory 22 including a storage device such as a RAM, a ROM, and a flash memory.

  The flight controller FC further includes a flight control sensor group S including an IMU 31 (Inertial Measurement Unit: inertial measurement device), a GPS receiver 32, a pressure sensor 34, and an electronic compass 36, which are connected to the control device 20. Have been.

  The IMU 31 is a sensor for detecting the inclination of the body of the multicopter 10, and mainly includes a three-axis acceleration sensor and a three-axis angular velocity sensor. The atmospheric pressure sensor 34 is an altitude sensor that calculates the altitude (altitude) above the sea level of the multicopter 10 from the detected atmospheric pressure altitude. A three-axis geomagnetic sensor is used for the electronic compass 36 of this example. The electronic compass 36 detects the azimuth of the nose of the multicopter 10. The GPS receiver 32 is a receiver of a navigation satellite system (NSS). The GPS receiver 32 acquires the current longitude and latitude values from the Global Navigation Satellite System (GNSS) or the Regional Navigational Satellite System (RNSS).

  The multicopter 10 of this example uses an optical flow sensor 33 in addition to the above-described GPS receiver 32 as a sensor for detecting the horizontal position. The optical flow sensor 33 is directed from the sensor housing 749 of the arm 70 to the ground surface, and detects the movement of the aircraft by performing pattern recognition of a captured image of the ground surface. This not only improves the accuracy of specifying the horizontal position, but also allows the multicopter 10 to fly indoors where GPS signals do not reach. In addition, the multicopter 10 of this example uses a laser distance measuring sensor 35 in addition to the above-described pressure sensor 34 as a sensor for detecting the flight altitude. The laser ranging sensor 35 is directed to the ground surface from the sensor housing 749 of the arm 70, and acquires the altitude above the ground. Thereby, it is possible to correct an error in the flight altitude due to a change in the atmospheric pressure.

  In addition, the multicopter 10 of this example is provided with a depth camera 37 and an ultrasonic sensor 38 for detecting peripheral objects in front of the body and measuring the distance and the like. In this example, the applications of the depth camera 37 and the ultrasonic sensor 38 are not particularly specified.

  The flight control sensor group S enables the flight controller FC to acquire its own position information including the longitude and latitude, altitude, and azimuth of the nose in addition to the tilt and rotation of the aircraft. Have been.

  The control device 20 has a flight control program FS that is a program for controlling the attitude and basic flight operation of the multicopter 10 during flight. The flight control program FS controls the rotation speed of each rotor R based on the information obtained from the flight control sensor group S, and causes the multicopter 10 to fly while correcting the disturbance of the attitude and position of the aircraft.

  The control device 20 further has an autonomous flight program AP that is a program for causing the multicopter 10 to fly autonomously. In the memory 22 of the control device 20, a flight plan FP, which is a parameter designating the latitude and longitude of the destination and the transit point of the multicopter 10, the altitude and speed during flight, and the like, is registered. The autonomous flight program AP can cause the multicopter 10 to fly autonomously in accordance with the flight plan FP with an instruction from the operator terminal 51 or a predetermined time as a start condition.

  As described above, the multicopter 10 of the present embodiment is an unmanned aerial vehicle having an advanced flight control function. However, the unmanned aerial vehicle of the present invention is not limited to the form of the multicopter 10, for example, an airframe in which some sensors are omitted from the flight control sensor group S, or can fly only by manual operation without an autonomous flight function. An airframe can also be used.

  As described above, the embodiments of the present invention have been described, but the scope of the present invention is not limited thereto, and various changes can be made without departing from the gist of the invention.

10: multicopter (unmanned aerial vehicle), FC: flight controller, S: flight control sensor group, 33: optical flow sensor, 35: laser ranging sensor, R: rotor,
41: brushless motor, 411: ESC, 42: propeller (horizontal rotary wing, foldable propeller), 70: arm, 70a: trunk, 70b: joint, 70c: fork, 71: one rod, 72 73: two rods, 74: connecting member, 74a: trunk side connecting portion, 74b: branch side connecting portion, 741-743: adapter member, 749: sensor housing, 76: motor mount, 761: clamp, 78 : Rotor guard, 781: fixed piece, 782: fixed clip, 789: hub, 79: landing gear

Claims (9)

A rotor having horizontal rotors,
An arm that supports the rotor,
The distal end of the arm is composed of two cylindrical rods that extend in the same direction and are arranged vertically.
Each of the rods supports a different one of the rotors,
The base end of the arm is constituted by one cylindrical rod,
Between the one rod and the two rods of the arm, the connecting portion of the hollow bifurcated toward the proximal side to the distal end side is provided,
An unmanned aerial vehicle, wherein a drive circuit of a brushless motor of the rotor is accommodated inside the connecting portion .   The unmanned aerial vehicle according to claim 1, wherein the rotors supported by the rods are arranged such that their rotating surfaces face each other. One end of the rotor guard is connected to one of the two rods, and the other end of the rotor guard is connected to the other,
The unmanned aerial vehicle according to claim 2, wherein the rotor guard is arranged to vertically surround the horizontal rotor.   The unmanned aerial vehicle according to claim 3, wherein the rotor guard is rotatable in a horizontal direction about a connection portion with the arm.   The unmanned aerial vehicle according to claim 3 or 4, wherein the rotor guard is an elongated linear frame. The unmanned aerial vehicle according to any one of claims 3 to 5 , wherein a plurality of the rotor guards are attached to the arm. The arms, unmanned aircraft according to any one of claims 1 to 5 shall be the wherein the from its proximal end is pivotable in the horizontal direction. The unmanned aerial vehicle according to any one of claims 1 to 7, wherein the horizontal rotor is a foldable propeller that can store the blade by bending the blade clockwise or counterclockwise. Comprising a plurality of said arms,
The base end of each of the arms and the vicinity thereof are configured as a single rod,
When the arms are horizontally turned in the same direction and folded, the arms are located between the two rods of each arm and at the proximal end of the adjacent other arm or in the vicinity thereof. 8. The unmanned aerial vehicle according to claim 7 , wherein the unmanned aerial vehicle is in a positional relationship within which the distance is settled.

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