JP6696653B2 - 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 to operate in order to stably fly. However, in recent years, there have been major improvements in the sensors and software used for attitude control and autonomous flight of unmanned aerial vehicles, which has significantly improved the operability of unmanned aerial vehicles and made it possible to obtain high-performance aircraft at low cost. .. From such a background, application of not only small multicopters but also various missions in a wide range of industrial fields is being tried, not only for hobby purposes.

  The following Patent Documents 1 and 2 disclose a multicopter including an arm and a frame that act as a rotor guard by covering the entire length of the rotor.

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

  In a general multi-copter, a structure in which a plurality of arms extend radially from the center of the body and a rotor is arranged at the tips of the arms is often adopted. These arms and rotors occupy most of the horizontal dimension of the airframe, which is a factor that reduces 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 arm so that the propellers do not come into contact with each other, and the horizontal size of the machine 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 like the multicopters of Patent Documents 1 and 2, the horizontal size of the machine body is significantly increased, and the problem of space efficiency becomes more serious. On the other hand, it is complicated to remove the arm or rotor guard or disassemble the machine each time the multicopter is transported or stored, which may cause an assembly error during flight.

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

  In order to solve the above problems, an unmanned aerial vehicle of the present invention includes a rotor having horizontal rotors, and an arm that supports the rotor, and a tip portion of the arm extends in the same direction arranged vertically. The rotor is composed of two rods, each rod supports another rotor, and the rotors supported by the rods are arranged so that their rotation surfaces face each other. One end of a rotor guard is connected to one of the rods of the book, and the other end of the rotor guard is connected to the other, and the rotor guard is arranged so as to surround the horizontal rotor in the up-down direction. To do.

  In an unmanned aerial vehicle having a large number of rotors such as an octacopter, a rotor may be a counter-rotating propeller to reduce the number of arms in order to reduce the horizontal size of the airframe. However, when arranging the rotors on the upper and lower surfaces of one arm, there is a problem that the thrust efficiency per rotor is reduced due to the close distance between these rotors. According to the present invention, the rotors arranged above and below are arranged on separate rods, so that the rotors can be arranged at a distance larger than that of the structure in which the rotors are arranged on the upper and lower surfaces of one arm. Further, the number of arms when the aircraft is viewed in plan can be reduced to half compared to the configuration in which the same number of rotors as the rotors of the unmanned aerial vehicle of the present invention are arranged on the same horizontal plane. As a result, it is possible to reduce the horizontal size of the airframe while reducing the decrease in thrust efficiency of the rotor.

  Since the tip of the arm is composed of two rods, the rotor is arranged on the inner surfaces of these two rods (the surfaces of the two rods facing each other). The rotors supported by the rods can be arranged so that their rotation surfaces face each other. This creates a space on the outer surface of the two rods where other members or devices can be placed. Furthermore, by connecting the end portions of the rotor guards to these rods, the horizontal rotor blades of both rotors can be vertically surrounded by one rotor guard.

  Further, it is preferable that the rotor guard is capable of turning in a horizontal direction around a connecting portion with the arm.

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

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

  The rotor guard can be reduced in weight by forming the rotor guard into an elongated linear frame body. By providing each arm with a plurality of arms, the safety performance of the rotor guard can be adjusted according to the operating environment of the unmanned aerial vehicle. For example, if the purpose is only to protect the propeller, it is sufficient to provide the most efficient number of rotor guards for the main shape of the surrounding objects, in order to ensure the safety of passersby in the event of an unexpected situation. In order to reduce the blind spot of the rotor guard, the number may be increased appropriately.

  Further, it is preferable that the arm can be horizontally swung from the base end portion or the middle thereof.

  Since the arm can be bent in the horizontal direction, it becomes possible to carry and store the unmanned aerial vehicle compactly without removing the arm each time. In particular, if the rotor guard is also foldable, the labor of removing the rotor guard can be saved. In particular, when the rotors are arranged such that their surfaces of rotation face each other, the vertical dimension of the machine body after folding the arms can also be kept small.

  At this time, the horizontal rotor is preferably a foldable propeller that can be stored by bending the blade clockwise or counterclockwise.

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

  The base end of the arm is composed of one rod, and when all the arms are folded, each of the bases of one adjacent arm fits between the two rods of the other arm. By arranging the arms, it becomes possible to fold the body more compactly.

  As described above, according to the unmanned aerial vehicle of the present invention, it is possible to improve space efficiency and portability of the airframe.

It is an appearance perspective view showing the state at the time of flight of a multicopter. It is an appearance perspective view showing a state at the time of transportation and storage of a multicopter. FIG. 3A is a side view of a deployed arm and a side view of a folded arm. FIG. 4 is a plan view of the arm shown in FIGS. 3A and 3B. It is a side view sectional drawing of Drawing 3 (a). It is a block diagram which shows the function structure of a multicopter.

  Embodiments of the present invention will be described below with reference to the drawings. The embodiment described below is an example of the multicopter 10 which is an unmanned aerial vehicle including a plurality of rotors. In the following description, “upper”, “lower”, and “vertical” are directions parallel to the Z axis of the coordinate axis display depicted in FIGS. 1 and 2, and the Z1 side is the upper side. Further, "horizontal (direction)" means the 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 a plan view.

[Airframe overview]
1 and 2 are perspective views showing the appearance of a multi-copter 10 according to this embodiment (hereinafter, also referred to as "this example"). FIG. 1 is a diagram showing a state of the multicopter 10 during flight. FIG. 2 is a diagram showing a state during transportation and storage of the multicopter 10.

  The multicopter 10 includes a rotor R having a propeller 42 that is a horizontal rotary blade, 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 with 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 machine body.

  The tip 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 rotation surfaces face each other.

  Two rod guards 78, which are elongated linear frames, are provided at the tips of the rods 72 and 73. The rotor guard 78 has one end connected to the tip of the upper rod 72 and the other end connected to the tip of the lower rod 73, and is deployed so as to surround the propeller 42 in the vertical direction.

  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 of the multicopter 10 and sensor parts are housed. Although the multi-copter 10 of this example is an example of a body for surveying, the laser scanner 90 is installed, but the application 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 multi-copter 10 of this example, the arm 70, the rotor guard 78, and the propeller 42 are all foldable, so that the multi-copter 10 can be transported and stored without removing them. It is possible to reduce the horizontal dimension of.

[Arms configuration]
Hereinafter, the structure of the arm 70 will be described with reference to FIGS. 3 to 5. FIG. 3A is a side view of the expanded 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. 3 (a) and 3 (b). FIG. 5 is a side view cross-sectional view of FIG. In the following description, the structure will be described by taking one of the four arms 70 of the multicopter 10 as an example. However, except for the type of sensor held in the sensor housing 749 described later, other arms 70 are provided. The basic structure of the same is the same. Further, in the following description, “base end side” means the arrow b side in the direction parallel to the arrows drawn in FIGS. 3 to 5, and “base end” means the end part on the base end side. Say. Similarly, the "tip side" refers to the arrow t side, and the "tip portion" refers to the end portion on the tip side.

(Structure overview)
The arm 70 of this example has a base portion 70a, a joint portion 70b, and a fork portion 70c. The base portion 70 a is a portion formed by one rod body 71 including the base end portion of the arm 70. The fork portion 70c is a portion including two rod bodies 72, 73 arranged on the distal end side of the arm 70, and a connecting member 74 connecting the rod bodies 72, 73 and the rod body 71. The joint portion 70b is a connecting portion between the trunk portion 70a and the fork portion 70c, and is a joint portion that allows the fork portion 70c to be bent in the horizontal direction. Note that the basic portion 70a, the joint portion 70b, and the fork portion 70c are bundles for convenience, and it is not necessary to strictly divide the boundaries thereof. 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 thereof.

(Basic and joint parts)
The rod body 71 that constitutes the basic portion 70a is a cylindrical pipe material made of CFRP (Carbon Fiber Reinforced Plastics). The rod 71 has its base end fixed to the above-mentioned center frame so as not to move, and its tip 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, which will be described later, form a joint portion 70b.

(Fork part)
As described above, the fork portion 70c of this example has the two rod bodies 72 and 73 that form the tip portion of the arm 70 and the connecting member 74.

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

  The connecting member 74 has a backbone-side connecting portion 74a and a branch-side connecting portion 74b. The backbone-side connecting portion 74a is a portion to which the rod body 71 is connected, and is configured by vertically arranging two flat plate members made of CFRP with their plate surfaces facing up and down. The branch-side connecting portion 74b is a portion to which the rod bodies 72 and 73 are connected, and is branched into two branches up and down from the base end side toward the tip end side, and is formed in a substantially U-shape in a side view. A CFRP flat plate material 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 rod bodies 72 and 73 are connected are fixed to the tip of the branch side connecting portion 74b.

  A landing gear 79, which is a leg portion extending downward from the branch-side connecting portion 74b, is coupled to a side surface of the branch-side connecting portion 74b. The landing gear 79 is formed by assembling a flat plate material made of CFRP into a rectangular tube shape. At the lower end of the landing gear 79, a rubber contact block that extends downward from the other parts of the landing gear 79 to mitigate collision with the ground or floor surface and prevent chipping or cracking of the landing gear 79. 791 is provided.

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

  In the multi-copter 10 of this example, since the rotors R arranged above and below are supported by the separate rods 72 and 73, for example, rather than the structure in which the rotors are arranged above and below one arm, these rotors R Can be placed a distance apart. Further, the number of arms when the plane is viewed in plan is suppressed to half compared to the configuration in which the same number of rotors as the rotors R of the multicopter 10 are arranged on the same horizontal plane. As a result, it is possible to reduce the horizontal dimension of the multicopter 10 while reducing the reduction in thrust efficiency per rotor R.

  The above-mentioned effect can be obtained even when the rotation surfaces of both rotors R supported by the rod bodies 72 and 73 are directed upward. On the other hand, in the present example, these rotors R are supported by the inner surfaces of the two rod bodies 72, 73 (the surfaces of the two rod bodies 72, 73 facing each other), and the rotation surfaces thereof are arranged so as to face each other. As a result, the vertical dimension of the machine body can be kept small when the arm 70 is folded.

  In addition, in the multicopter 10 of this example, when all the arms 70 are folded, the trunk portion 70a and the joint portion 70b (the trunk side connecting portion 74a) of the one arm 70 that are adjacent to each other are replaced by the fork portion of the other arm 70. It is placed between 70c (see FIG. 2).

  The base end side portion of the arm 70 is configured as one rod body (basic portion 70a, backbone side connecting portion 74a) in the up-and-down direction with two rod bodies constituting the fork portion 70c of the adjacent arm 70. By making the positions different, it is possible to prevent the folded arms 70 from interfering with each other and to fold the body more compactly.

  Further, as shown in FIG. 5, the ESC 411 (Electric), which is a drive circuit of the brushless motor 41 (hereinafter, simply referred to as “motor 41”) included in the rotor R, is provided inside the branch side connecting portion 74 b of the connecting member 74. Speed Controller) is housed. The 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 this example, the ESC 411 can be arranged at a position apart 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 that holds the optical flow sensor 33 is integrally formed with the plate-shaped member that constitutes the lower surface of the branch side connection portion 74b. In the multicopter 10 of the present example, the pair of arms 70, which are located in positions symmetrical with respect to each other in the circumferential direction of the airframe, have the optical flow sensor 33 in the sensor housing 749 thereof and the sensor housing 749 of the other pair of arms 70 in the sensor housing 749. The laser distance measuring sensor 35 is held. The type of 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 connecting portion 74b and arranging an arbitrary sensor there, the degree of freedom in the mounting position of the sensor is increased and the possibility of expanding the function using the sensor is possible. Can be expanded. Furthermore, what is provided on the upper and lower surfaces of the branch side connecting portion 74b is not limited to the sensor housing, and may be, for example, a connecting 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 be given any purpose.

  It should be noted that the multicopter 10 of the present example obtains additional performance associated with 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. Alternatively, for example, the base end portions of the two rod bodies 72 and 73 may be directly fixed to the center frame.

(Rotor guard)
The rotor guard 78 is a frame body formed by joining small diameter pipe materials made of CFRP. A hub portion 789 that supports the rotor guard 78 is provided at the tips of the rods 72 and 73. The rotor guard 78 has one end connected to the upper rod body 72 and the other end connected to the lower rod body 73, and is developed so as to surround the rotor R (propeller 42) of the rod bodies 72 and 73 in the vertical direction. To be done.

  In the multi-copter 10 of this example, the tip of the arm 70 is composed of two rods 72, 73, and the inner surface of the two rods 72, 73 (two rods 72, 73 Rotors R are arranged respectively on the surfaces facing each other). In addition to this, by connecting the ends of the rotor guard 78 to the rod bodies 72 and 73, it is possible to surround the propellers 42 of both rotors R with the one rotor guard 78 in the vertical direction.

  Further, each rotor guard 78 is horizontally rotatable about the hub portion 789. When transporting / storing the multicopter 10, the rotor guard 78 can be compactly stored by folding the rotor guard 78 so as to extend parallel to the side surface of the fork portion 70c.

  Each arm 70 has two rotor guards 78, respectively. These rotor guards 78 can be deployed 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 the shaft body (not shown) of the hub portion 789, and the position of the rotor guard 78 is fixed. Further, the rods 72 and 73 are provided with clips 782 that hold the folded rotor guard 78.

  Although the arm 70 of this example has two rotor guards 78, the number of the rotor guards 78 included in one arm 70 is not limited to two, and it may be changed according to the usage environment of the multicopter 10. It can be adjusted appropriately. For example, in the case of only protecting the propeller 42, it is sufficient to provide the most efficient number of rotor guards 78 with respect to the main shape of the surrounding objects, so as to ensure the safety of passersby in an unexpected situation. If desired, the number of rotor guards 78 may be appropriately increased to reduce the blind spots.

  Further, the rotor guard 78 of this example employs an elongated linear frame because it is lightweight and suitable for folding, but the rotor guard of the present invention has the form of this example. It is not limited to. The rotor guard of the present invention may be, for example, a wide removable rotor guard, provided that it surrounds the rotor R (propeller 42) of the rods 72, 73 in the vertical direction. Furthermore, 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 this example, the two rod bodies 72 and 73 that support the rotor R are shorter than the diameter of the propeller 42. In the multi-copter 10 of this example, the arm 70 is not provided with the protection function of the rotor R, and the support of the rotor R and the protection of the rotor R are separated. As a result, enlargement of the horizontal dimension of the machine body is avoided, and when the protection of the rotor R is not necessary, it can be easily omitted.

(propeller)
The propeller 42 of the rotor R is a foldable propeller capable of folding the blade clockwise or counterclockwise.

  Thus, in the multicopter 10 of this example, the arm 70 is horizontally foldable, and the rotor guard 78 and the propeller 42 are also foldable. Accordingly, when transporting and storing the multi-copter 10, it is possible to easily enhance the space efficiency and portability without removing any constituent member of the arm 70.

  Although the folding structure of the arm 70, the rotor guard 78, and the propeller 42 described above is extremely significant in improving the space efficiency and portability of the multicopter 10, these are selectable elements, and these folding structures are also included. 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 multi-copter 10 are a flight controller FC which is a control unit, a plurality of rotors R, an ESC 411 which is a drive circuit of a brushless motor 41 which constitutes the rotor R, a communication device 52 which communicates with a driver (operator terminal 51), It is composed of a laser scanner 90 which is an external device for surveying, and a battery 80 which supplies electric power to these.

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

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

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

  The multi-copter 10 of this example uses an optical flow sensor 33 in combination with the GPS receiver 32 described above as a sensor for detecting the horizontal position thereof. The optical flow sensor 33 is directed from the sensor housing 749 of the arm 70 to the ground surface, and detects movement of the machine body by pattern recognition of a captured image of the ground surface. As a result, not only the accuracy of identifying the horizontal position can be improved, but also the multicopter 10 can be made to fly even indoors where GPS signals do not reach. In addition, the multi-copter 10 of this example uses a laser distance measuring sensor 35 in addition to the above-described atmospheric pressure sensor 34 as a sensor for detecting the flight altitude. The laser distance measuring sensor 35 is directed to the ground surface from the sensor housing 749 of the arm 70 and acquires the ground altitude. As a result, it is possible to correct the flight altitude error due to the change in atmospheric pressure.

  In addition, the multi-copter 10 of this example is provided with a depth camera 37 and an ultrasonic sensor 38 that detect a peripheral object in front of the machine body and measure the distance and the like. In this example, the uses of the depth camera 37 and the ultrasonic sensor 38 are not particularly specified.

  With the flight control sensor group S, the flight controller FC can acquire the position information of the aircraft including the longitude and latitude of the aircraft, the altitude, and the azimuth of the nose, in addition to the tilt and rotation of the aircraft. Has been done.

  The control device 20 has a flight control program FS, which is a program for controlling the attitude and basic flight operation of the multicopter 10 during flight. The flight control program FS adjusts the rotation speed of each rotor R based on the information acquired from the flight control sensor group S, and causes the multi-copter 10 to fly while correcting the disturbance of the attitude and position of the airframe.

  The control device 20 further has an autonomous flight program AP that is a program for causing the multicopter 10 to fly autonomously. Then, in the memory 22 of the control device 20, the flight plan FP, which is a parameter in which the latitude and longitude of the destination and the waypoint of the multi-copter 10 and the altitude and speed during flight are designated, is registered. The autonomous flight program AP can cause the multicopter 10 to fly autonomously according to the flight plan FP by using an instruction from the operator terminal 51 or a predetermined time as a start condition.

  As described above, the multi-copter 10 of this example 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 multi-copter 10, and for example, the aircraft in which some of the sensors are omitted from the flight control sensor group S, or the aircraft is not equipped with an autonomous flight function and can fly only by manual operation. An airframe can also be used.

  Although the embodiment of the present invention has been described above, the scope of the present invention is not limited to this, and various modifications can be made without departing from the spirit 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 rotor, folding type propeller), 70: Arm, 70a: Core part, 70b: Joint part, 70c: Fork part, 71: One rod, 72 , 73: two rods, 74: connecting member, 74a: backbone side connecting part, 74b: branch side connecting part, 741-743: adapter member, 749: sensor housing, 76: motor mount, 761: clamp, 78 : Rotor guard, 781: Fixed piece, 782: Fixed clip, 789: Hub part, 79: Landing gear

Claims (7)

A rotor having horizontal rotors,
An arm supporting the rotor,
A member that is a separate member from the arm, and includes a rotor guard that prevents the rotor from contacting the peripheral object by hitting the peripheral object in advance when approaching the peripheral object, and
The tip portion of the arm is composed of two rod bodies arranged in the vertical direction and extending in the same direction,
On the tip side of each of the rods, the different rotors are supported so that their rotation surfaces face each other ,
One end of the rotor guard on one of the two rods are, in Rukoto is other to connect the other end of the rotor guard, the rotor guard being arranged to surround the horizontal rotor blade in the vertical direction Unmanned aerial vehicle characterized by.   The unmanned aerial vehicle according to claim 1, wherein the rotor guard is rotatable in a horizontal direction around a connecting portion with the arm.   The unmanned aerial vehicle according to claim 1 or 2, wherein the rotor guard is an elongated linear frame body. The unmanned aerial vehicle according to any one of claims 1 to 3 , wherein a plurality of the rotor guards are attached to the arm. The unmanned aerial vehicle according to any one of claims 1 to 4, wherein the arm can pivot horizontally from a base end portion or a middle portion thereof. The unmanned aerial vehicle according to any one of claims 1 to 5, wherein the horizontal rotor is a foldable propeller that can be stored by bending the blade clockwise or counterclockwise. A plurality of said arms,
The base end portion of each arm and the vicinity thereof are configured as one rod body,
When the arms are horizontally swiveled in the same direction and folded, the plurality of arms are arranged between the two rod bodies of the respective arms, and a base end portion of another adjacent arm or a portion in the vicinity thereof. The unmanned aerial vehicle according to claim 5 , characterized in that

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