JP7270324B2 - unmanned aerial vehicle - Google Patents

Description

The present invention relates to an unmanned aerial vehicle having multiple rotors.

2. Description of the Related Art Conventionally, inspections of railway viaducts are mainly performed using aerial work vehicles and the like. In places where aerial work vehicles cannot be used, inspections are carried out by rope aerial work. Rope work at height refers to work performed by suspending a rope by tightening it from a support above the work site and using a device to hold the body on the rope (Occupational Safety and Health Regulations 36 (see article). It is desired to further improve the safety of high-elevation work in places where such high-elevation work vehicles cannot be used.

Therefore, it is conceivable to use a drone (commonly known as) to take an image of an object to be inspected at a high place with a camera instead of working at a high place. A drone is an unmanned aerial vehicle defined by the Japanese Industrial Standards (JIS) (see Non-Patent Document 1).

An unmanned flight inspection machine is known as an unmanned aircraft used for inspection (see Patent Document 1). However, since this unmanned flight inspection machine has a spherical outer frame (frame body), the outer frame is reflected in the captured image.

2. Description of the Related Art An unmanned flying object (unmanned aerial vehicle) in which a plurality of cameras are provided on a spherical frame (frame body) is known (see Patent Document 2). Since the camera is provided outside the frame, the frame is not visible in the camera image. However, this unmanned aerial vehicle is heavy due to a spherical frame made up of many frames and a plurality of cameras, which increases the load on the motor that drives the propeller (rotor blade) and shortens the flight time.

A small unmanned aerial vehicle for inspection (unmanned aerial vehicle) covered with a rectangular parallelepiped net frame (frame body) is known (see Patent Document 3). A rectangular parallelepiped frame can be constructed with fewer frame members than a spherical frame, but there is an orientation angle with respect to the fuselage. This small unmanned aerial vehicle has shafts, bearings, etc., in order to allow the body to tilt with respect to the mesh frame when moving forward or backward. However, since the fuselage of this small unmanned aerial vehicle does not incline to the left or right with respect to the mesh frame, the centrifugal force received by the mesh frame is directly transmitted to the fuselage when flying in a curved direction, and there is a risk that the flight may become unstable. .

Also, an unmanned aerial vehicle is known that includes a frame that forms the outer shape of a housing (see Patent Document 4). This unmanned aerial vehicle moves on the inspection surface by pressing the wheels of the frame against the wall surface (inspection surface) to be inspected (wall surface traveling). In this unmanned aerial vehicle, the rotor is movably supported, and when traveling on a wall surface, the pitch angle and roll angle of the rotor change within the movable range while maintaining the posture of the frame relative to the wall surface. However, when this unmanned aerial vehicle flies in the air away from the wall surface, the angle of the rotor with respect to the frame may not be fixed within the floatable range, and the flight may become unstable. In addition, the configuration for movably supporting the rotor is complicated, and the weight of the unmanned aerial vehicle increases.

JP 2019-167017 A JP 2016-180866 A JP 2017-124691 A JP 2018-144627 A

JIS W 0141:2019 "Unmanned Aerial Vehicles - Vocabulary"

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems, and to provide an unmanned aerial vehicle in which the frame covering the airframe hardly interferes with imaging, etc., and in which flight stability is high against the inertial force generated in the frame. .

An unmanned aerial vehicle of the present invention has a plurality of rotor wings, and includes a body and a body having the rotor wings, and a frame covering the body, wherein the frame is a plurality of elongated frames. It has a rectangular parallelepiped outer shape made of a material and is supported by the body via an anisotropic flexible part having flexibility, and the anisotropic flexible part distributes the load of the frame to the body. In addition to transmitting, the frame body is flexed due to elastic deformation by both lateral force and longitudinal force applied to the frame, and the easiness of bending in the lateral direction and the longitudinal direction can be set to different magnitudes.

In this unmanned aerial vehicle, the anisotropic flexible section is composed of a plurality of flexible members that are spaced apart in the left and right direction, and each of the flexible members vertically connects the frame and the body. and is flexible against horizontal forces.

In this unmanned aerial vehicle, it is preferable that the flexible member is made of anti-vibration rubber.

In this unmanned aerial vehicle, the anisotropic flexible section is composed of a plurality of flexible members that are spaced apart in the left-right and front-rear directions, and each of the flexible members vertically extends the frame and the body. and flexible against horizontal forces.

In this unmanned aerial vehicle, the flexible member is preferably a spring.

In this unmanned aerial vehicle, it is preferable that the body has an imaging device, and the imaging device is provided so that the frame body does not enter the imaging range of the imaging device.

According to the unmanned aerial vehicle of the present invention, the frame that covers the airframe has a rectangular parallelepiped outer shape, so it can be configured with fewer frame members than a frame with a spherical outer shape, and it is less likely to interfere with imaging. In addition, since the frame is supported by the body via the anisotropic flexible portion having flexibility in the left-right direction and the front-rear direction, the horizontal force transmitted from the frame to the body is alleviated. The aircraft has high flight stability against the inertial force generated in the frame. Furthermore, the anisotropic flexible portion can be set to different degrees of flexibility in the left-right direction and in the front-back direction. The unmanned aerial vehicle is more stable in flight against the inertial force generated in the frame.

1 is a drawing-substituting photograph of an unmanned aerial vehicle according to a first embodiment of the present invention; A perspective view of a frame in the unmanned aerial vehicle. FIG. 2 is a perspective view of the anisotropic flexible portion and its peripheral portion in the same unmanned aerial vehicle; Drawing substitute photograph of the same anisotropic flexible part and its peripheral part. FIG. 8 is a perspective view of an anisotropically flexible portion and its peripheral portion in an unmanned aerial vehicle according to a second embodiment of the present invention; Drawing substitute photograph of the same anisotropic flexible part and its peripheral part.

(First embodiment)
An unmanned aerial vehicle according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 4. FIG. According to Japanese Industrial Standards, "unmanned aerial vehicles" are airplanes, rotorcraft, gliders, airships, etc. that can be used for aviation, and which cannot be operated by humans due to their structure. Alternatively, it can be flown by autopilot (see No. 1001 of Non-Patent Document 1). As shown in the overall photograph of FIG. 1, the unmanned aerial vehicle 1 of this embodiment is a rotary wing unmanned aerial vehicle having a plurality of rotary wings 2 (see No. 1021 of Non-Patent Document 1). The unmanned aerial vehicle 1 is also called a drone. In this embodiment, the number of rotor blades 2 is four.

This unmanned aerial vehicle 1 includes a body 3 and a frame 5 . Airframe 3 has fuselage 4 and rotor 2 . A frame 5 covers the body 3 . The frame 5 is also called a guard.

The airframe 3 has a configuration of a general drone, and includes a motor that rotates the rotor blades 2, a control device (flight controller), a GPS receiver, an acceleration sensor, a wireless receiver, a storage battery, and the like.

The airframe 3 has an imaging device 6 in addition to the above configuration. The imaging device 6 is a camera, an infrared image sensor, or the like, and is used to image an inspection object or the like. The imaging device 6 is provided so that the frame body 5 does not enter its imaging range.

As shown in FIG. 2, the frame 5 has a rectangular parallelepiped outer shape made up of a plurality of elongated frame members (511 to 515).

As shown in FIGS. 3 and 4, the frame 5 is supported by the body 4 via an anisotropic flexible portion 7 having flexibility. In FIG. 3, the body 4 and the frame 5 represent the vicinity of the anisotropic flexible portion 7. As shown in FIG. The anisotropic flexible portion 7 transmits the load of the frame 5 to the body 4 . The anisotropic flexible portion 7 is elastically deformed by both the lateral force and the longitudinal force applied to the frame 5, and the easiness of bending in the lateral direction and the longitudinal direction can be set to different magnitudes. In addition, flexibility is a property of being able to bend by an external force. According to elastic mechanics, the flexibility of the anisotropic flexible portion 7 is quantitatively represented by the amount of deformation of the anisotropic flexible portion 7 with respect to external force.

Here, the configuration of the frame body 5 will be described in detail. The frame 5 has an outer frame 51 and lateral beams 52 (see FIG. 2). The outer frame 51 has a rectangular parallelepiped shape by combining a plurality of elongated frame members. The cross beam 52 extends inside the outer frame 51 and has both ends coupled to frame members on the left and right surfaces of the outer frame 51 . The outer frame 51 has a frame member at least on each side of the rectangular parallelepiped. The frame members on each side are four vertical frames 511 in the vertical direction, four horizontal frames 512 in the horizontal direction, and four side frames 513 in the front-rear direction. The upper and lower surfaces of the outer frame 51 are surrounded by a horizontal frame 512 and a side frame 513, respectively, and have no frame material for reinforcement and form a large opening. Side columns 514 and side beams 515 for reinforcement are provided on the left and right sides surrounded by the vertical frame 511 and the side frames 513 . Each side pillar 514 vertically connects each intermediate portion of the side frames 513 forming a pair in the vertical direction. Each side sill 515 connects each central part of the longitudinal frame 511 and the side pillar 514 therebetween in the front-rear direction. The horizontal beam 52 connects the center portions of the left and right side beams 515 in the left-right direction. A central portion of the lateral beam 52 is supported by the body 4 via the anisotropic flexible portion 7 (see FIG. 3).

The anisotropic flexible section 7 is composed of a plurality of flexible members 71 spaced apart in the left and right direction. Each flexible member 71 connects the frame 5 and the body 4 in the vertical direction and has flexibility against force in the horizontal direction (left-right direction and front-rear direction).

As the number of flexible members 71 in the left-right direction increases, the anisotropic flexible portion 7 becomes more difficult to bend in the left-right direction. Also, the larger the horizontal distance between the flexible members 71, the more difficult it is to bend in the horizontal direction. In this embodiment, the number of flexible members 71 constituting the anisotropic flexible section 7 is two, and they are arranged symmetrically on the body 4 . Therefore, the anisotropic flexible portion 7 is more flexible in the front-rear direction than in the left-right direction.

In this embodiment, the flexible member 71 is made of anti-vibration rubber. Anti-vibration rubber is rubber that is attached to mechanical equipment to support load and prevent transmission of vibration. Category”. The specific selection of the vibration-isolating rubber for the flexible member 71 is a matter of design, and a vibration-isolating rubber that is elastically deformed moderately by the force applied to the anisotropic flexible portion 7 but not plastically deformed is used.

In the unmanned aerial vehicle 1 configured as described above, when the unmanned aerial vehicle 1 is stationary on a horizontal plane, the unmanned aerial vehicle 1 receives vertical gravity, and the airframe 3 and the frame body 5 assume a normal posture and position. Become. That is, at that time, the body 3 and the frame 5 are not tilted. When the unmanned aerial vehicle 1 flies and accelerates or decelerates in the longitudinal direction, an inertial force in the longitudinal direction is generated in the frame 5 , and the inertial force is transmitted to the body 4 by the anisotropic flexible portion 7 . At that time, the anisotropic flexible portion 7 bends in the front-rear direction, so the inertial force transmitted to the body 4 is alleviated. Further, when the unmanned aerial vehicle 1 flies while turning in the left-right direction (at the time of turning), a centrifugal force (inertial force in the left-right direction) is generated in the frame 5 , and the centrifugal force is transferred to the fuselage by the anisotropic flexible portion 7 4. At that time, the anisotropic flexible portion 7 bends in the left-right direction, so that the centrifugal force transmitted to the body 4 is alleviated. Since the anisotropic flexible portion 7 bends due to elastic deformation, the bending is canceled when the inertial force of the frame 5 disappears.

As described above, according to the unmanned aerial vehicle 1 according to the present embodiment, the frame body 5 that covers the airframe 3 has a rectangular parallelepiped outer shape, so that it can be configured with fewer frame members than a frame body having a spherical outer shape. hard to do In addition, since the frame 5 is supported by the body 4 via the anisotropic flexible portion 7 having flexibility in the left-right direction and the front-rear direction, the horizontal force transmitted from the frame 5 to the body 4 is is relaxed, and the flight stability of the unmanned aerial vehicle 1 against the inertial force generated in the frame 5 is enhanced. Furthermore, since the anisotropic flexible portion 7 can be set to different degrees of flexibility in the left-right direction and in the front-to-rear direction, it is possible to set the degree of flexibility suitable for flight stability in each direction. , the unmanned aerial vehicle 1 is more stable in flight against the inertial force generated in the frame 5 .

In addition, the anisotropic flexible portion 7 transmits the load of the frame 5 to the body 4, and at the same time, it is elastically deformed by both the left-right force and the front-rear force applied to the frame 5. No swivel bearings are required to support 5. Therefore, the unmanned aerial vehicle 1 has a simple configuration and is lightweight.

Since the anisotropic flexible section 7 is composed of a plurality of flexible members 71 spaced apart in the left and right direction, depending on the number of flexible members 71 in the left and right direction and the distance between the flexible members 71 in the left and right direction, , the degree of flexing in the left-right direction and in the front-rear direction can be easily set to different sizes.

In the first embodiment, since the flexible member 71 is made of anti-vibration rubber, the flexible member 71 is elastically deformed by both lateral force and longitudinal force, and the vibration of the frame 5 with respect to the body 4 is damped. .

Since the frame 5 has a rectangular parallelepiped outer shape, the imaging device 6 can be easily installed on the fuselage 3 so that the frame 5 does not enter the imaging range even when the fuselage 3 is covered with the frame 5 .

(Second embodiment)
An unmanned aerial vehicle 1 according to a second embodiment of the present invention will be described with reference to FIGS. 5 and 6. FIG. The unmanned aerial vehicle 1 of this embodiment has the same configuration as that of the first embodiment, except for the configuration of the anisotropically flexible portion. The same reference numerals are assigned to portions equivalent to those of the first embodiment. In the following description, the description of parts equivalent to those of the first embodiment will be omitted.

As shown in FIGS. 5 and 6, in this embodiment, the anisotropic flexible portion 70 is composed of a plurality of flexible members 72 spaced apart in the left-right and front-rear directions. Each flexible member 72 connects the frame 5 and the body 4 in the vertical direction and has flexibility against horizontal force.

The anisotropic flexible portion 70 becomes less likely to bend in the left-right direction as the number of flexible members 72 in the left-right direction increases, and becomes more difficult to bend in the front-rear direction as the number of flexible members 72 increases in the front-rear direction. In addition, the anisotropic flexible portion 70 is less likely to bend in the left-right direction as the left-right interval of the flexible member 72 increases, and becomes less likely to bend in the front-rear direction as the front-rear interval increases. In this embodiment, the number of flexible members 72 constituting the anisotropic flexible section 70 is two in the left and right direction and two in the front and back direction, i.e., the same number in the left and right direction and the front and back direction. arranged symmetrically. The interval between the flexible members 72 is larger in the left-right direction than in the front-rear direction. Therefore, the anisotropic flexible portion 70 is more flexible in the front-rear direction than in the left-right direction.

In a second embodiment, flexible member 72 is a spring. The spring is a coil spring and is axially vertical at rest when not subjected to horizontal forces. The specific selection of the spring of the flexible member 72 is a matter of design, and a spring that is appropriately elastically deformed by the force applied to the anisotropic flexible portion 70 but not plastically deformed is used.

In the unmanned aerial vehicle 1 configured as described above, when the unmanned aerial vehicle 1 is stationary on a horizontal plane, the unmanned aerial vehicle 1 receives vertical gravity, and the airframe 3 and the frame body 5 assume a normal posture and position. It's becoming That is, at that time, the body 3 and the frame 5 are not tilted. When the unmanned aerial vehicle 1 flies and accelerates or decelerates in the longitudinal direction, an inertial force in the longitudinal direction is generated in the frame 5 , and the inertial force is transmitted to the body 4 by the anisotropic flexible portion 70 . At that time, the anisotropic flexible portion 70 bends in the front-rear direction, so the inertial force transmitted to the body 4 is alleviated. In addition, when the unmanned aerial vehicle 1 flies while bending in the horizontal direction, a centrifugal force is generated in the frame 5 , and the centrifugal force is transmitted to the body 4 by the anisotropic flexible portion 70 . At that time, the anisotropic flexible portion 70 bends in the left-right direction, so that the centrifugal force transmitted to the body 4 is alleviated. Since the anisotropic flexible portion 70 bends due to elastic deformation, the bending is canceled when the inertial force of the frame 5 disappears.

As described above, according to the unmanned aerial vehicle 1 according to the present embodiment, the anisotropic flexible section 70 is composed of a plurality of flexible members 72 that are spaced apart in the left-right and front-rear directions. Depending on the number of flexible members 72 in the left-right direction and the front-rear direction, and the distance between the flexible members 72 in the left-right direction and the front-rear direction, the easiness of bending in the left-right direction and the front-rear direction can be easily set to different magnitudes.

In the second embodiment, since the flexible member 72 is a spring, the magnitude of the elastic modulus can be easily set, and the flexible member 72 bends due to elastic deformation due to both lateral force and longitudinal force. The swinging of the frame 5 with respect to the body 4 is attenuated by the internal loss of the spring. As a modification of this embodiment, the damping coefficient of the anisotropic flexible portion 70 may be made larger than that of the spring alone by providing an anti-vibration rubber in parallel with the spring.

As an example of the present invention, an unmanned aerial vehicle 1 was made (see FIG. 1). Then, a test of flying the unmanned aerial vehicle 1 was conducted.

(Comparative example)
As a comparative example, the anisotropic flexible portions 7 and 70 of the unmanned aerial vehicle 1 were omitted, and the frame 5 was rigidly connected to the airframe 3 .

The unmanned aerial vehicle of this comparative example sometimes crashed. This is because the repetitive vibration of the frame 5 (guard) causes the acceleration sensor provided on the airframe 3 to react excessively.

As Example 1, an unmanned aerial vehicle 1 is provided with an anisotropic flexible section 7 having a flexible member 71 made of anti-vibration rubber. This configuration is the unmanned aerial vehicle 1 of the first embodiment (see FIG. 4).

The unmanned aerial vehicle 1 of Example 1 had high flight stability. In particular, the stability during curved flight was improved compared to the comparative example. In addition, the imaging device 6 (camera) is in focus because there is no frame member of the frame 5 in front of it. The unmanned aerial vehicle 1 is lighter than a spherical drone having a spherical frame. The flight mode (flight mode) of the spherical drone is sports mode. On the other hand, the unmanned aerial vehicle 1 of Example 1 was able to respond to all flight modes including tripod mode, GPS mode, and sport mode. Since this unmanned aerial vehicle 1 can fly in the tripod mode, it is easy to operate.

In Example 2, the unmanned aerial vehicle 1 is provided with the anisotropic flexible portion 70 in which the flexible member 72 is a spring. Other configurations were the same as those of the first embodiment. This configuration is the unmanned aerial vehicle 1 of the second embodiment (see FIG. 6).

The unmanned aerial vehicle 1 of Example 2 had high flight stability as in Example 1.

According to the comparative example, Example 1, and Example 2, it was confirmed that the anisotropic flexible portions 7 and 70 improved flight stability.

The present invention is not limited to the configurations of the above-described embodiments, and various modifications are possible without changing the gist of the invention. For example, the flexibility of the flexible member 71 made of vibration-isolating rubber may be set according to the lateral and longitudinal dimensions.

1 Unmanned aerial vehicle 2 Rotor 3 Body 4 Body 5 Frame 6 Imaging device 7, 70 Anisotropic flexible section 71 Flexible member (anti-vibration rubber)
72 flexible member (spring)

Claims (5)

An unmanned aerial vehicle having multiple rotor blades,
a fuselage having a fuselage and the rotor;
and a frame covering the airframe,
The frame body has a rectangular parallelepiped outer shape made up of a plurality of elongated frame members, and is supported by the body via an anisotropic flexible portion having flexibility,
The anisotropic flexible portion transmits the load of the frame to the body, and is elastically deformed by both the left-right force and the front-rear force applied to the frame. Flexibility can be set to different sizes,
The anisotropic flexible portion is composed of a plurality of flexible members spaced apart from each other to the left and right,
The unmanned aerial vehicle, wherein each flexible member connects the frame and the body in a vertical direction and has flexibility against a force in a horizontal direction. 2. The unmanned aerial vehicle according to claim 1 , wherein said flexible member is made of anti-vibration rubber. An unmanned aerial vehicle having multiple rotor blades,
a fuselage having a fuselage and the rotor;
and a frame covering the airframe,
The frame has a rectangular parallelepiped outer shape made up of a plurality of elongated frame members, and is supported by the body via an anisotropic flexible portion having flexibility,
The anisotropic flexible portion transmits the load of the frame to the body, and is elastically deformed by both lateral and longitudinal forces applied to the frame. Flexibility can be set to different sizes,
The anisotropic flexible portion is composed of a plurality of flexible members spaced apart in the left-right and front-rear directions,
The unmanned aerial vehicle, wherein each flexible member connects the frame and the body in a vertical direction and has flexibility against a force in a horizontal direction. 4. The unmanned aerial vehicle of claim 3 , wherein said flexible member is a spring. The aircraft has an imaging device,
The unmanned aerial vehicle according to any one of claims 1 to 4 , wherein the imaging device is provided so that the frame body does not enter an imaging range of the imaging device.

Images