Patent Description:
When a rotor in an unmanned aerial vehicle malfunctions or stops working, a known conventional technique allows a parachute to be deployed so that the unmanned vehicle can fall at a reduced speed. For example, <CIT> discloses such a technique. <CIT> discloses an unmanned aerial vehicle configured to stop plural rotors and deploy a parachute from an ejection mechanism when detecting its collision with an obstacle.

<CIT>, according to its abstract, states a flight body comprising a machine body to which three or more rotary wings are attached; a kite wing which is pivotally supported to the machine body and which has flexibility; and a control part which controls practical inclination of the kite wing relative to the machine body.

<CIT>, according to its abstract, states an unmanned aerial vehicle ("UAV") and system that may perform one or more techniques for protecting objects from damage resulting from an unintended or uncontrolled impact by a UAV. Various implementations utilize a damage avoidance system that detects a risk of damage to an object caused by an impact from a UAV that has lost control and takes steps to reduce or eliminate that risk. For example, the damage avoidance system may detect that the UAV has lost power and/or is falling at a rapid rate of descent such that, upon impact, there is a risk of damage to an object with which the UAV may collide. Upon detecting the risk of damage and prior to impact, the damage avoidance system activates a damage avoidance system having one or more protection elements that work in concert to reduce or prevent damage to the object upon impact by the UAV.

<CIT>, according to its abstract, states an UAV apparatus having a frame structure, a plurality of primary arm structures extending from the frame structure, a driving system for driving the UAV apparatus, and a recovery system. The recovery system includes plurality of foldable arms pivotally mounted to the plurality of primary arm structures at the free end area of the primary arm structures, the plurality of foldable arms being configured to be moved from a closing position where the foldable arms extend along the primary arm structures with their free ends pointing towards the frame structure, towards an open position where the free ends point away from the frame structure, a foldable material mounted to the foldable arms, a locking-unlocking system configured to maintain the plurality of foldable arms in a closing position, where in response to a malfunction signal indicating a malfunction in the UAV apparatus, the locking-unlocking system is configured to release the plurality of foldable arms from the closing position to an open position and thus deploy the foldable material to at least to reduce the vertical velocity of the UAV apparatus.

<CIT>, according to its abstract, states a flight vehicle safety device equipped with a safety mechanism, a drive mechanism, an ejection mechanism, and a control mechanism. The safety mechanism is used to ensure the safety of a flight vehicle and/or an object outside the flight vehicle. The drive mechanism has one or more drive units which function as a drive source for the safety mechanism. The ejection mechanism ejects the drive mechanism along with the safety mechanism. The control mechanism controls the operation of the drive mechanism in a manner such that the safety mechanism is driven by the drive mechanism after ejection of the safety mechanism by the ejection mechanism has started.

The parachute is useful to reduce the fall speed. However, the deployed parachute may get caught on a tree or a tall building. There is still room for improvement to reduce the risk of accidental contact during the falling.

An object of the present invention, which has been made under such circumstances, is to provide an unmanned aerial vehicle that can fall at a reduced speed with a reduced risk of accidental contact with a building or other object even when its rotor stops working.

An aspect of the present invention is directed to an unmanned aerial vehicle, as defined in claim <NUM>.

The present invention makes it possible to provide an unmanned aerial vehicle that can fall at a reduced speed with a reduced risk of accidental contact with a building or other object even when its rotor stops working.

Hereinafter, non-limiting exemplary embodiments of the present invention will be described with reference to the drawings. <FIG> is a plan view showing an unmanned aerial vehicle <NUM> according to an embodiment of the present invention.

The unmanned aerial vehicle <NUM> shown in <FIG> is a vehicle that is capable of flying in an unmanned manner, known as a drone. The term "capable of flying in an unmanned manner" means the ability to fly with no human pilot on board and is intended to cover not only autonomous flying vehicles but also human remote-controlled unmanned flying vehicles.

The unmanned aerial vehicle <NUM> includes a main body <NUM>, arms <NUM> as supports extending from the main body <NUM>, rotors <NUM> supported by the arms <NUM>, and a sail deployment system <NUM> that operates in an emergency, etc..

The main body <NUM> is located at a center of the unmanned aerial vehicle <NUM> in plan view and equipped with a controller <NUM> and electronic devices such as sensors including a camera (e.g., a computer including a CPU, a memory, and other components and configured to execute a control program).

The arm <NUM> is a support having one end connected to the main body <NUM> and the other end (hereinafter referred to as the "distal end") provided with the rotor <NUM>. In this embodiment, four (plural) arms <NUM> extend radially (in radial directions) from the main body <NUM> in plan view. The four arms <NUM> are spaced at equal intervals along the circumferential direction in plan view.

The rotor <NUM> is supported on the main body <NUM> through the arm <NUM>. Specifically, the rotor <NUM> is rotatably disposed on an upper surface of the distal end of the arm <NUM>. A rotor motor <NUM> connected to the rotor <NUM> is built in the distal end of the arm <NUM>. As the rotor motor <NUM> rotates, the rotor <NUM> is rotated to produce a lift force that enables the unmanned aerial vehicle <NUM> to fly.

The sail deployment system <NUM> includes cloth-like parts 51a to 51d that function as sails and deployment mechanisms 60a to <NUM> that function as drive units to switch the cloth-like parts <NUM> from a standby state to a deployed state.

The cloth-like parts 51a to 51d will be described. During normal flight, the cloth-like parts 51a to 51d are in a standby state in which they are folded at positions close to the main body <NUM>.

The standby state will be described. The cloth-like part <NUM> is made of a material whose area in plan view can be made smaller in the standby state than in the deployed state.

The cloth-like parts 51a to 51d are creased so that they can be folded in a corrugated fashion in the standby state. In the standby state, the folded cloth-like part <NUM> has bent portions <NUM> at both distal ends, which are formed by folding an end portion of the cloth-like part <NUM>. The bent portions <NUM> leave margins for the distal side length of the cloth-like part <NUM> in the deployed state.

The cloth-like parts 51a to 51d may be made of a stretchable elastic thin film material, a fiber cloth, a nonwoven fabric, a plastic material having an air-fillable layer, or any other appropriate material. In this embodiment, the cloth-like parts 51a to 51d may not have creases or the bent portions <NUM> depending on the elasticity of the material of the cloth-like parts 51a to 51d, how to crease, or how to stand by. Therefore, the standby state may be achieved using any propriate material and method as long as the cloth-like part <NUM> can be made smaller in the standby state than in the deployed state.

On the other hand, in the deployed state shown in <FIG>, the circumferential space is filled between the arms <NUM> in plan view. The cloth-like parts 51a to 51d are each deployed by means of a pair of two of the deployment mechanisms 60a to <NUM> located on both sides of each of the cloth-like parts 51a to 51d. In this regard, the term "deployed state" refers to any state in which, in plan view, the area of the cloth-like part <NUM> between the arms <NUM> is larger than that in the standby state. The spaces between the arms <NUM> arranged in the circumferential direction are filled by the cloth-like parts 51a to 51d in the deployed state. In this embodiment, the deployed state is intended to include not only a state in which the spaces between the arms <NUM> are entirely filled over the circumferential direction but also a state in which a space remains between the arms <NUM> and the cloth-like parts 51a to 51d.

Referring to <FIG> and <FIG> with alphanumeric characters assigned in clockwise order, the cloth-like part 51a is driven by a pair of the deployment mechanisms 60a and 60b. Similarly, the cloth-like part 51b is driven by a pair of the deployment mechanisms 60c and 60d, the cloth-like part 51c is driven by a pair of the deployment mechanisms 60e and 60f, and the cloth-like part 51d is driven by a pair of the deployment mechanisms <NUM> and <NUM>. In this embodiment, two of the deployment mechanisms <NUM> handle one cloth-like part <NUM>. Therefore, the four cloth-like parts 51a to 51d are handled by eight deployment mechanisms 60a to <NUM>.

The deployment mechanisms 60a to <NUM> have the same structure. The cloth-like parts 51a to 51d have the same shape and are made of the same material. Next, the configuration of the deployment mechanisms 60a to <NUM> will be described. In the description below of the common features of the deployment mechanisms 60a to <NUM> and the cloth-like parts 51a to 51d, the alphabetic characters will be omitted from the reference signs.

<FIG> is a side view showing the cloth-like part <NUM> in the standby state and the configuration of the deployment mechanism <NUM> in the unmanned aerial vehicle <NUM> of this embodiment. In <FIG>, the hollow arrow indicates the direction in which the cloth-like part <NUM> is moved when switched from the deployed state to the standby state. <FIG> is a side view showing the cloth-like part <NUM> in the deployed state and the configuration of the deployment mechanism <NUM>. In <FIG>, the hollow arrow indicates the direction in which the cloth-like part <NUM> is moved when switched from the standby state to the deployed state.

As shown in <FIG> and <FIG>, the deployment mechanism <NUM> includes a deployment motor <NUM>, a driving gear <NUM>, a driven gear <NUM>, a toothed belt <NUM>, a rail <NUM>, a connecting slider <NUM>, plural driven sliders <NUM>, and a body-fixed part <NUM>.

The deployment motor <NUM> is a driving unit provided in the arm <NUM>. The driving gear <NUM> is connected to the deployment motor <NUM>. As the deployment motor <NUM> rotates, the driving gear <NUM> is rotated. In this embodiment, the deployment motor <NUM> is configured so that its direction and speed of rotation are controllable. For example, a stepping motor or the like is used as the deployment motor <NUM>.

The driven gear <NUM> is spaced apart from the driving gear <NUM> in a direction away from the main body <NUM> and rotatably fixed with a fastener such as a bracket (not shown). The toothed belt <NUM> is an endless member that is engaged with and looped around the driving gear <NUM> and the driven gear <NUM>. The toothed belt <NUM> is rotatably supported by the arm <NUM>, having its longitudinal direction along the direction in which the arm <NUM> extends.

The rail <NUM> is provided adjacent to the toothed belt <NUM> and fixed to the arm <NUM>. The rail <NUM> also has its longitudinal direction along the direction in which the arm <NUM> extends. The connecting slider <NUM> and the plural driven sliders <NUM> are slidably engaged with the rail <NUM>.

The connecting slider <NUM> is disposed closer to the distal end of the arm <NUM> than the plural driven sliders <NUM>. The connecting slider <NUM> is fixed to a distal end of the cloth-like part <NUM> and connected to the toothed belt <NUM>. As the toothed belt <NUM> rotates, the connecting slider <NUM> is moved in the longitudinal direction of the arm <NUM> while being guided by the rail <NUM>.

The plural driven sliders <NUM> are fixed to portions of the cloth-like part <NUM> spaced from one another. Unlike the connecting slider <NUM>, the driven sliders <NUM> are not connected to the toothed belt <NUM>. Therefore, the driven sliders <NUM> are not directly moved together with the rotating toothed belt <NUM>.

The body-fixed part <NUM> is provided to fix a proximal end of the cloth-like part <NUM> to the main body <NUM>. Thus, even when the cloth-like part <NUM> is switched from the standby state to the deployed state, an appropriate distance is kept between the main body <NUM> and the cloth-like part <NUM>.

Referring to <FIG>, for example, as the deployment motor <NUM> rotates clockwise as viewed in the drawing, the toothed belt <NUM> is rotated clockwise to move the connecting slider <NUM> rightward to a right-hand side as viewed in the drawing. As the connecting slider <NUM> is moved toward the distal end of the arm <NUM>, the cloth-like part <NUM> is moved toward the distal end. The driven sliders <NUM> are pulled through the cloth-like part <NUM> being moved toward the distal end so that they are also moved toward the distal end along the rail <NUM>. Since the driven sliders <NUM> are engaged with the cloth-like part <NUM>, an appropriate distance is kept between the cloth-like part <NUM> and the arm <NUM> during the movement of the cloth-like part <NUM>.

Similarly, as the deployment motor <NUM> rotates counterclockwise as viewed in the drawing, the connecting slider <NUM> is moved leftward as viewed in the drawing. As the connecting slider <NUM> is moved toward the main body <NUM> side of the arm <NUM>, the driven sliders <NUM> are pushed by the connecting slider <NUM> and moved toward the main body <NUM> side. The cloth-like part <NUM> is smoothly folded with the aid of the creases formed in advance and turned into the standby state. During the transition from the deployed state to the standby state, an appropriate distance is kept between the cloth-like part <NUM> and the arm <NUM> by means of the driven sliders <NUM> engaged with the cloth-like part <NUM>, so that the folding operation goes smoothly.

The deployment operation by the deployment mechanisms 60a to <NUM> is controlled by the controller <NUM>. <FIG> is a block diagram showing an electrical configuration for the deployment control in the unmanned aerial vehicle <NUM> of this embodiment.

The controller <NUM> is a computer configured to execute various control processes necessary for the flight and other operations of the unmanned aerial vehicle <NUM>. The controller <NUM> is electrically connected to: detectors for detecting various pieces of information, such as a camera <NUM>, a gyro sensor <NUM>, and an acceleration sensor <NUM>; a communication device <NUM> that transmits and receives signals to and from external devices such as an operation controller and GPS; and so on.

In this embodiment, the controller <NUM> includes an abnormality determination section <NUM> that determines whether or not any abnormality occurs in the unmanned aerial vehicle <NUM>; and a deployment control section <NUM> that controls the sail deployment system <NUM>. The abnormality determination section <NUM> and the deployment control section <NUM> are implemented by some of the programs stored in the controller <NUM>.

The abnormality determination section <NUM> determines whether or not any abnormality occurs in the unmanned aerial vehicle <NUM> based on various pieces of information indicating abnormalities, which are input in the controller <NUM>. Examples of abnormalities determinable by the abnormality determination section <NUM> include any failure or malfunction in a component of the unmanned aerial vehicle <NUM>, such as the rotor <NUM>, situations in which strong winds or other factors make safe flight impossible, and situations in which the remaining battery level is low after long-duration flight. The abnormalities may be of any type, and various situations may be registered as abnormalities in the controller <NUM>.

An example of a method for determining an abnormality will be described. The abnormality determination section <NUM> may determine whether or not an abnormality occurs based on a detection signal from a sensor or any other component that detects the driving current through the rotor motor <NUM> or rotation failure of the rotor motor <NUM>. Alternatively, the abnormality determination section <NUM> may determine whether or not an abnormality occurs based on information from various sensors including the camera <NUM>, the gyro sensor <NUM>, and the acceleration sensor <NUM>, which indicates the flight conditions of the unmanned aerial vehicle <NUM>. These pieces of information may be combined and used to determine whether or not an abnormality occurs.

When the user determines that it is difficult to continue the flight of the unmanned aerial vehicle <NUM>, the occurrence of an abnormality may be determined based on information input from the outside, such as an apparatus for remotely operating the unmanned aerial vehicle <NUM>. The abnormality determination section <NUM> may use various types of information to determine whether or not an abnormality occurs.

The deployment control section <NUM> will be described. When the abnormality determination section <NUM> determines that an abnormality occurs, the deployment control section <NUM> performs a deployment control to cause the deployment mechanisms 60a to <NUM> to deploy the cloth-like parts <NUM>. Hereinafter, the control will be described with alphabetic characters attached to the reference numeral <NUM> for the deployment motor so that the deployment motors 55a to <NUM> are distinguished corresponding to the deployment mechanisms 60a to <NUM>.

The deployment motors 55a <NUM> are independently controllable. The deployment motors 55a to <NUM> are all configured so that their rotational direction and rate of movement are controllable, which allows control of the direction and amount of movement of the connecting slider <NUM>.

Further, the deployment control section <NUM> is configured to selectively control the deployment motors 55a to <NUM> depending on the conditions of the unmanned aerial vehicle <NUM>. In this embodiment, synchronized control is possible between the deployment motors 55a and 55b, between the deployment motors 55c and 55d, between the deployment motors 55e and 55f, and between the deployment motors <NUM> and <NUM>.

An example of the deployment control section <NUM> will be described. In this embodiment, the deployment control section <NUM> controls each of the deployment motors 55a to <NUM> based on the abnormality determined by the abnormality determination section <NUM>.

If the rotor motor <NUM> of the unmanned aerial vehicle <NUM> malfunctions or stops working, the unmanned aerial vehicle <NUM> may be allowed to fall without determining where to fall. In this case, the deployment motors 55a to <NUM> are driven to turn all the cloth-like parts 51a to 51e into the deployed state. In this case, as shown in <FIG>, all the spaces between the arms <NUM> are filled over the circumferential direction. Where to fall may not be determined, for example, if the abnormality determination section <NUM> determines that the current location of the unmanned aerial vehicle <NUM> is in an area where there is no person, dangerous object, building, or other object at the time point when determining that an abnormality occurs.

Next, another case will be described in which the fall direction or speed is controlled if the rotor motor <NUM> of the unmanned aerial vehicle <NUM> malfunctions or stops working. The fall direction or speed may be controlled, for example, if the abnormality determination section <NUM> determines that the current location of the unmanned aerial vehicle <NUM> is in an area where there is no person or there is any dangerous object, building, or other object at the time point when determining that an abnormality occurs.

<FIG> is a plan view showing how the cloth-like parts 51a to 51d are deployed when the unmanned aerial vehicle <NUM> according to this embodiment is in a low-speed mode. In <FIG>, the hollow arrow indicates the direction to travel, which is upward in the drawing. As shown in <FIG>, in the low-speed mode, the cloth-like parts 51a, 51c, and 51d are selected from the plural cloth-like parts 51a to 51d and deployed, except for the cloth-like part 51b located ahead in the direction set to travel. The cloth-like part 51b located ahead in the direction to travel is in the standby state or in a state in which the amount of deployment is smaller than that indicted by the dot-dash line. In this regard, the amount of deployment of the cloth-like part <NUM> may be adjusted depending on the current location and condition of the unmanned aerial vehicle <NUM>.

When the amount of deployment of the cloth-like part 51b located ahead in the direction to travel is made smaller than the amount of deployment of the other cloth-like parts 51a, 51c, and 51d, the air resistance is made relatively small on the side located ahead in the direction to travel, so that the unmanned aerial vehicle <NUM> can travel in the set direction while falling.

<FIG> is a plan view showing how the cloth-like parts 51a to 51d are deployed when the unmanned aerial vehicle <NUM> according to this embodiment is in a medium-speed mode. In <FIG>, the hollow arrow indicates the direction to travel, which is left upward in the drawing. As shown in <FIG>, in the medium-speed mode, the extending direction of one of the plural arms <NUM> is set as the direction to travel.

In the medium-speed mode, the two cloth-like parts 51c and 51d located on both sides of the arm <NUM> located opposite to the arm <NUM> located ahead in the direction to travel are in the deployed state, while the two cloth-like parts 51a and 51b located on both sides of the arm <NUM> located ahead in the direction to travel are in the standby state or in a state in which the amount of deployment is smaller than that indicated by the dot-dash line. In this case, the difference in air resistance between the downstream and upstream sides in the direction of travel is larger than that in the low-speed mode shown in <FIG>, so that the unmanned aerial vehicle <NUM> can fall at a higher speed. In this regard, the amount of deployment of the cloth-like part <NUM> may be adjusted depending on the current location and condition of the unmanned aerial vehicle <NUM>.

<FIG> is a plan view showing how the cloth-like parts 51a to 51d are deployed when the unmanned aerial vehicle <NUM> according to this embodiment is in a high-speed mode. As shown in <FIG>, in the high-speed mode, only the cloth-like part 51d located upstream in the direction of travel is in the deployed state, while the remaining cloth-like parts 51a, 51b, and 51c are in the standby state or in a state in which the amount of deployment is smaller than that indicated by the dot-dash line. In this regard, the amount of deployment of the cloth-like part <NUM> may be adjusted depending on the current location and condition of the unmanned aerial vehicle <NUM>.

For example, when the unmanned aerial vehicle <NUM> is in an area where it should not fall on the ground, the medium- or high-speed mode may be used so that the unmanned aerial vehicle <NUM> is allowed to leave the area smoothly and to fall more safely.

As is apparent from the above description, each embodiment of the present invention brings about advantageous effects thanks to the features mentioned below.

An unmanned aerial vehicle (<NUM>) according to an embodiment of the present invention includes a main body (<NUM>); plural supports (<NUM>) that extend from the main body (<NUM>) and support rotors (<NUM>); cloth-like parts (<NUM>) held in a standby state in which the cloth-like parts (<NUM>) are folded at positions close to the main body (<NUM>); and deployment mechanisms (<NUM>) that are provided in the supports (<NUM>) and each configured to move a portion of the cloth-like part (<NUM>) in a direction away from the main body (<NUM>) so that the cloth-like part (<NUM>) is switched from the standby state to a deployed state in which the cloth-like part (<NUM>) is spread between the supports (<NUM>) in plan view. According to the embodiment, the cloth-like part (<NUM>) deployed between the supports (<NUM>) functions like a patagium of a flying squirrel to reduce the fall speed with wind drag applied thereon. The cloth-like part (<NUM>) stretched between the supports (<NUM>) can significantly reduce the risk of accidental contact with a tree, a building, or other objects during falling as compared to a parachute.

The unmanned aerial vehicle (<NUM>) according to an embodiment of the present invention may further includes a controller <NUM> serving as a control section that controls the deployment mechanisms (<NUM>) to switch the cloth-like part (<NUM>) between the standby state and the deployed state. Thus, the controller <NUM> enables the cloth-like part (<NUM>) to be turned into the deployed state at an appropriate time depending on the current condition of the unmanned aerial vehicle <NUM>.

In the unmanned aerial vehicle (<NUM>) according to an embodiment of the present invention, the controller (<NUM>) may control the deployment mechanisms (<NUM>) to switch the cloth-like part (<NUM>) from the standby state to the deployed state when detecting an abnormality. According to the embodiment, when a problem such as malfunction of the rotor (<NUM>) occurs and it is determined that an abnormality occurs, the cloth-like part (<NUM>) is reliably deployed so that the unmanned aerial vehicle (<NUM>) is prevented from falling freely, which provides a further improvement in safety.

In the unmanned aerial vehicle (<NUM>) according to an embodiment of the present invention, the controller (<NUM>) may control the amount of movement in a direction in which the arm (<NUM>) extends to control the amount of deployment of the cloth-like part (<NUM>) in the deployed state. According to the embodiment, the control of the amount of deployment makes it possible to control the unmanned aerial vehicle (<NUM>) depending on conditions.

In the unmanned aerial vehicle (<NUM>) according to an embodiment of the present invention, the cloth-like parts (51a, 51b, 51c, 51d) may each be provided between a pair of the supports (<NUM>). Plural pairs of deployment mechanisms (60a and 60b, 60c and 60d, 60e and 60f, <NUM> and <NUM>) may be provided, and the number of the plural pairs of deployment mechanisms (60a and 60b, 60c and 60d, 60e and 60f, <NUM> and <NUM>) may correspond to the number of cloth-like parts (51a, 51b, 51c, and 51d). In addition, the controller (<NUM>) may selectively deploy the plural cloth-like parts (51a, 51b, 51c, 51d). According to the embodiment, the degree of deployment of the cloth-like parts (51a, 51b, 51c, 51d) can be adjusted in the circumferential direction in plan view, which allows the unmanned aerial vehicle <NUM> to fall at a precisely controlled speed in a precisely controlled direction. Based on dangerous area information input from the camera <NUM> or external information sources, it is possible to control where the unmanned aerial vehicle <NUM> is to fall in such a way as to avoid areas in which any person or dangerous object exists. As used herein, the phrase "selectively deploy" is intended to also include the case in which all the cloth-like parts (51a, 51b, 51c, 51d) are deployed.

In the unmanned aerial vehicle (<NUM>) according to an embodiment of the present invention, the deployment mechanism (<NUM>) may include a deployment motor (<NUM>); a driving rotary part (<NUM>) connected to the deployment motor (<NUM>); a driven rotary part (<NUM>) spaced apart from the driving rotary part (<NUM>) in a direction in which the support (<NUM>) extends; an endless member (<NUM>) looped around the driving rotary part (<NUM>) and the driven rotary part (<NUM>); and a connecting part (<NUM>) fixed to the cloth-like part (<NUM>) and fixed to the endless member (<NUM>). According to the embodiment, as the endless member (<NUM>) rotates, the cloth-like part (<NUM>) is more reliably spread and switched from the standby state to the deployed state. In addition, it is possible to more precisely control the amount of deployment. Further, as the endless member (<NUM>) rotates in the reverse direction, switching from the deployed state to the standby state is easily performed.

In the unmanned aerial vehicle (<NUM>) according to an embodiment of the present invention, the deployment mechanism (<NUM>) may further include a rail (<NUM>) which extends in a direction in which the support (<NUM>) extends and with which the connecting part (<NUM>) is slidably engaged; and plural engagement parts (<NUM>) that are slidably engaged with the rail (<NUM>) at positions closer to the main body (<NUM>) than the connecting part (<NUM>) and fixed to portions of the cloth-like part (<NUM>) spaced from one another. According to the embodiment, the cloth-like part (<NUM>) can be more smoothly spread along the direction in which the support (<NUM>) extends while a large gap is prevented from forming between the cloth-like part (<NUM>) and the support (<NUM>). In the embodiment, the phrase "the plural engagement parts fixed to portions of the cloth-like part spaced from one another" means that the engagement parts can be located at intervals in the extending direction on the cloth-like part in the deployed state.

While embodiments of the present invention have been described above, it will be understood that the embodiments are not intended to limit the present invention and may be altered or modified within the scope of the present invention as long as the object of the present invention can be achieved.

The configuration of the deployment mechanism <NUM> according to the embodiment may be altered or modified in any appropriate way. The deployment mechanism <NUM> may include a chain as the endless member and sprockets as the driving and driven rotary parts. Alternatively, the deployment mechanism <NUM> may include a non-toothed belt as the endless member and pulleys as the driving and driven rotary parts. Alternatively, the deployment mechanism <NUM> may be configured without using any endless member. Alternatively, the deployment mechanism <NUM> may be configured so that the deployed state is not returnable to the standby state. For example, an elastic member such as a spring, an explosive, or other means may be used for a deployment mechanism for turning the cloth-like part <NUM> into the deployed state.

While four cloth-like parts <NUM> are provided in the embodiment described above, it will be understood that such a configuration is non-limiting. Alternatively, two, three, or five or more cloth-like parts may be provided. Alternatively, a single cloth-like part may be provided below the supports to surround the periphery of the main body and configured to be radially spread when it is switched from the standby state to the deployed state.

The unmanned aerial vehicle <NUM> of the embodiment may include a holding part that holds the cloth-like part <NUM> in the standby state. The holding part may be a grip configured to grip the cloth-like part <NUM> in a folded state or a housing box configured to accommodate the cloth-like part in the standby state. For example, the housing box may be configured so that the cloth-like part <NUM> pops out of its opening when the standby state is changed to the deployed state.

While the embodiments described above show an example in which the cloth-like part <NUM> is spread and switched from the standby state to the deployed state when the controller <NUM> determines that an abnormality occurs, it will be understood that such a configuration is non-limiting. Alternatively, the cloth-like part may be turned into the deployed state even when the rotor <NUM> stops working.

Claim 1:
An unmanned aerial vehicle (<NUM>) comprising
a main body (<NUM>),
a plurality of supports (<NUM>), each support (<NUM>) extending from the main body (<NUM>) and supporting a rotor (<NUM>),
a cloth-like part (<NUM>) provided between each pair of the supports (<NUM>) and held in a standby state in which the cloth-like part (<NUM>) is folded at a position close to the main body (<NUM>);
at least one deployment mechanism (<NUM>) that is provided in the support (<NUM>) and configured to move a portion of the cloth-like part (<NUM>) in a direction away from the main body (<NUM>) so that the cloth-like part (<NUM>) is switched from the standby state to a deployed state in which the cloth-like part (<NUM>) is spread between the supports (<NUM>) in plan view, and
a controller (<NUM>) that controls the deployment mechanism (<NUM>) to switch the cloth-like part (<NUM>) between the standby state and the deployed state,
characterized in that,
the at least one deployment mechanism (<NUM>) includes a plurality of deployment mechanisms, and the number of the deployment mechanisms (<NUM>) corresponds to the number of the cloth-like parts (<NUM>), and
the controller (<NUM>) selectively deploys the cloth-like parts (<NUM>).