UAV

Abstract

A UAV (1) attachable to an external target, the UAV comprising: a propulsion system (2); an arm (3) extending away from the propulsion system; and a releasable attachment element (4) connected to the arm and configured to releasably attach to the external target. The propulsion system and the attachment element are coupled via a coupling mechanism (5) interposed between the arm and the propulsion system or between the arm and the attachment element.

Description

Technical Field

[0001] This invention relates to an unmanned aerial vehicle (UAV) that can be attached to an external target. Background Technology

[0002] UAVs that can be attached to external targets can be used in a wide range of applications that require close interaction between the UAV and the external target.

[0003] For example, a UAV that can be attached to an external target can be used in inspection or manipulation applications, where the external target is the structure to be inspected or manipulated.

[0004] Among the structures that are routinely inspected and manipulated, some structures present significant challenges, such as cargo holds, bridges, dams, offshore platforms, oil refineries, power plants, chemical plants, and high-rise buildings, to name just a few.

[0005] Manual on-site inspection and manipulation of such structures can be extremely time-consuming, expensive, complex, and often dangerous for the individuals performing the task. Therefore, there is a need in this industry to address this problem.

[0006] WO2023 / 079523A1 discloses a UAV for non-destructive testing (NDT) of structures, the UAV comprising: an external protective cage; a propulsion system mounted inside the external protective cage; an arm including a first end attached to the external protective cage; and an NDT sensor mounted at a second end of the arm. The arm extends outward from the external protective cage, thereby facilitating measurements in hard-to-reach locations.

[0007] WO2023 / 079523A1 also discloses that a structural engagement surface, configured to engage with a target surface on the structure to be measured, can be defined at the second end of the arm. Specifically, the second end may include means for securing the structural engagement surface to the structural surface. This arrangement ensures that the NDT sensor remains on the target surface throughout the measurement process.

[0008] The drawback of this solution is that the engagement between the arm and the target surface constrains the propulsion system, thereby interfering with flight stability.

[0009] This problem is particularly noticeable when the engagement between the arm and the target surface creates a hinge at the bottom of the external protective cage. In this case, the flight controller needs to counteract the torque generated by this hinge, which is undesirable.

[0010] Furthermore, standard flight controllers are typically unable to maintain stable flight when torque is applied to the propulsion system. Therefore, there is a need in the industry for a UAV that can attach to an external target without causing flight controller failure.

[0011] WO2019 / 232217A1 discloses a drone that can fly to the vicinity of a structure to measure one or more parameters of the structure. The drone's electromagnet can be activated to electromagnetically attach the drone to the structure for inspection. Probes can be activated to inspect the structure by measuring one or more parameters.

[0012] US2021 / 339845A1 discloses a UAV comprising: an external protective cage; a propulsion system mounted inside the external protective cage; a sensor support system fixed to the external protective cage; and a sensor system coupled to the sensor support system. The sensor system is coupled to the sensor support system via a load-limiting coupling mechanism including a spring coupling that applies an elastic bias against the sensor system in a normal operating position. Upon collision with an external object, the sensor system retracts into the external protective cage against the elastic bias of the spring coupling.

[0013] WO2022 / 251956A1 discloses a UAV system comprising a UAV, a payload deployment system, and a payload. The payload deployment system includes a payload attachment system, a payload decoupling system, and an optional payload separation system. The payload attachment system is configured to attach the payload to a landing site such that the payload is at least partially supported by the landing site. The payload decoupling system is configured to decouple the payload from the UAV, allowing the UAV to move within its range of motion while the payload remains attached to the landing site. Summary of the Invention

[0014] The technical problem solved by the present invention is to provide a UAV that is configured in structure and function to at least partially overcome one or more of the disadvantages described in the prior art cited above.

[0015] In this regard, the first objective of the present invention is to provide a UAV capable of accurately targeting external targets.

[0016] A second objective of this invention is to provide a UAV capable of maintaining stable contact with an external target.

[0017] Another object of the present invention is to provide a reliable UAV, particularly for inspection and / or manipulation applications.

[0018] Another object of the present invention is to provide a universal UAV suitable for inspecting and / or manipulating various structures.

[0019] This problem is addressed, at least in part, by providing a UAV that can be attached to an external target, and these objectives are achieved. The UAV includes a propulsion system (particularly a flight propulsion system) and an arm, which preferably extends from the propulsion system. The UAV may also include a releasable attachment element connected to the arm and configured to be releasably attached to an external target.

[0020] In one embodiment, the arm extends longitudinally between a first end connected to the propulsion system and a second end opposite to the propulsion system. An attachment element may be attached to the second end of the arm.

[0021] Preferably, the propulsion system and the attachment element are connected via a coupling mechanism. In one embodiment, the coupling mechanism is located between the arm and the propulsion system or between the arm and the attachment element. More specifically, the coupling mechanism may be located between a first end of the arm and the propulsion system or between a second end of the arm and the attachment element.

[0022] The coupling mechanism may include a releasable rigid coupling that advantageously provides stable rigid positioning of the arm in a predefined operating position. It is understood that stable rigid positioning of the arm in the predefined operating position allows for precise targeting of external targets during flight. In embodiments, the predefined operating position of the arm may refer to a predetermined relative position of the arm with respect to the propulsion system (particularly if the coupling mechanism is positioned between the propulsion system and the arm) or a predetermined relative position of the arm with respect to the attachment element (particularly if the coupling mechanism is positioned between the arm and the attachment element).

[0023] Preferably, when the UAV is attached to an external target, the rigid coupling is releasable under the application of a force or torque greater than a predetermined threshold. Advantageously, this predetermined threshold is selected such that the arm is held in a predefined operating position when targeting the external target, and the rigid coupling is released upon attachment to the external target. It is understood that the release of the rigid coupling frees the propulsion system from the hinge constraints created by the arm's attachment to the external target. Therefore, the release of the rigid coupling protects the propulsion system from the transmission of external torque and allows the propulsion system to tilt about its center of gravity, thereby improving flight stability. Furthermore, the release of the rigid coupling allows the propulsion system to adjust its position, for example, to compensate for crosswinds during hovering flight, without the attachment element losing contact with the external target. As used herein, the term "torque" preferably refers to a force that generates or tends to generate undesirable rotation of the propulsion system, particularly transmitted from the arm to the propulsion system upon contact with an external target.

[0024] The coupling mechanism may also include a resilient coupling that preferably applies a resilient bias that causes the arm to move toward a predefined operating position. In this way, the arm can return to the predefined operating position when the UAV disengages from an external target.

[0025] More specifically, the resilient coupling is configured to allow the propulsion system to move relative to the attachment element against resilient bias when the rigid coupling is released, and preferably, the resilient coupling is also configured to restore the rigid coupling when the UAV detaches from an external target. This allows for multiple attachments of the UAV in the same flight without requiring manual restoration of the arm to a predefined operating position.

[0026] External targets can be structures to be inspected and / or manipulated. As used herein, the term “structure” should be understood in a broad sense, referring not only to buildings but also to other types of structures such as aircraft structures, cargo holds, fuel tanks, sewers, electrical grids, to name just a few.

[0027] In addition to those mentioned above, the present invention may also have one or more of the following preferred features.

[0028] In implementations, the UAV includes means mounted on an arm, particularly on a second end of the arm. This means is advantageously configured to inspect and / or manipulate an external target when the arm is attached to it. Therefore, it is preferable that the means is an inspection and / or manipulation device. It is also preferable that the means includes inspection and / or manipulation tools. It is understood that stable, rigid positioning of the arm in a predefined operating position allows for precise positioning of the means relative to the external target. Furthermore, attachment elements connected to the arm ensure stable contact with the external target for the desired inspection / manipulation.

[0029] As used herein, the term "inspection" preferably refers to measuring properties of an external target (e.g., wall thickness), sensing defects in an external target (e.g., cracks, corrosion, deformation, etc.), capturing images of an external target, and / or sampling an external target. Accordingly, the inspection apparatus may include a sensor, preferably a non-destructive testing (NDT) sensor, and more preferably an ultrasonic sensor. In a preferred embodiment, the apparatus further includes a coupling agent dispensing nozzle for delivering coupling agent. Alternatively or additionally, the apparatus may include an eddy current sensor, a video camera for capturing moving or still images, a sampler, etc.

[0030] As used herein, the term "manipulation" preferably refers to performing an action on an external target that causes some change to the external target. For example, manipulating an external target can include cleaning, brushing, welding, drilling, marking, painting, and / or printing on the external target. Accordingly, manipulation devices can include, for example, cleaning tools (e.g., brushes or cleaning pads), welding machines, drills, markers, painting tools, and / or printers for printing on external targets.

[0031] In this embodiment, the device is configured to contact an external target during inspection / manipulation. For this reason, it is preferable that the device and the attachment element are arranged on the arm such that the device contacts the external target when the attachment element is attached to the external target.

[0032] Preferably, the coupling mechanism is positioned between the propulsion system and the arm, and more particularly between the propulsion system and the first end of the arm. It is understood that this arrangement allows for minimizing the distance between the propulsion system and the coupling mechanism, thereby reducing the lever arm's torque transmitted to the propulsion system before the rigid coupling is released when the arm is attached to an external target.

[0033] In this implementation, the UAV also includes a flexible coupling positioned between the arm (particularly the second end of the arm) and the attachment element. More specifically, the coupling mechanism is positioned between the propulsion system and the first end of the arm, while the flexible coupling is positioned between the second end of the arm and the attachment element. It is understood that the presence of both the coupling mechanism and the flexible coupling provides two decoupling points between the propulsion system and the external target. This arrangement of two decoupling points allows the propulsion system to rotate about the UAV's center of gravity. Since the center of gravity is typically located at the origin of the UAV's roll, pitch, and yaw axes, this arrangement allows for more stable control of the propulsion system.

[0034] In one embodiment, the flexible coupling includes an elastic element (e.g., a spring, such as a helical spring; or an elastic material, such as an elastomer) that applies an elastic bias that causes the attachment element to align toward a predefined attachment position.

[0035] Alternatively or additionally, the flexible coupling may include a second coupling mechanism, which may be similar to the coupling mechanism used to connect the first end of the arm to the propulsion system. More specifically, the second coupling mechanism may include a second releasable rigid coupling that provides stable rigid positioning of the attachment element in a predetermined attachment position and is releasable when the UAV is attached to an external target under the application of a force or torque greater than a corresponding predetermined threshold. The second coupling mechanism may also include a second resilient coupling that applies a resilient bias that causes the attachment element to move toward the predetermined attachment position, and the second resilient coupling is configured to: allow the arm to move relative to the attachment element against the resilient bias when the second rigid coupling is released; and to restore the second rigid coupling when the UAV disengages from the external target. It is understood that the second coupling mechanism, the second releasable rigid coupling, and the second resilient coupling may also have one or more features disclosed herein with reference to coupling mechanisms, releasable rigid couplings, and resilient couplings (as the case may be).

[0036] Optionally, the propulsion system includes an external protective cage. In this way, the propulsion system can withstand impacts with external objects, especially external targets.

[0037] Preferably, the arm (particularly the first end of the arm) is connected to the outer protective cage and, more preferably, extends to the outside of the outer protective cage. In this way, the arm is better exposed to contact with the external target, while the outer protective cage can be kept at a safe distance from the external target.

[0038] In this embodiment, the coupling mechanism is positioned between the outer protective cage and the arm, and more particularly between the outer protective cage and the first end of the arm. In this way, the outer protective cage can be decoupled from the external target when the arm is attached to the external target.

[0039] In this embodiment, the coupling mechanism includes a first coupling end and a second coupling end. One of these coupling ends can be connected to the end of the arm, while the other coupling end can be connected to a propulsion system or attachment element. The first and second coupling ends can be coupled to each other, preferably in a releasable manner, particularly via a releasable rigid coupling. Alternatively, the first and second coupling ends can be coupled to each other via a resilient coupling. Advantageously, the first and second coupling ends are configured to provide an arm in a predefined operating position when they are coupled together. Furthermore, it is advantageous that the first and second coupling ends are configured to decouple when subjected to a torque greater than a predetermined threshold, particularly by forming an angle with each other.

[0040] The releasable rigid coupling may include a magnetic coupling, such as comprising two magnets, for example, one magnet on a first coupling end and another magnet on a second coupling end. It is understood that, in embodiments, the magnetic coupling may include a magnet or ferromagnetic element on the first coupling end and a complementary ferromagnetic element or magnet on the second coupling end. The ferromagnetic element may be made of a ferromagnetic material, such as an iron alloy. In this way, the magnetic coupling can ensure that the first and second coupling ends are positioned in a stable and correctly oriented position relative to each other. Additionally or alternatively, the releasable rigid coupling may include an electromagnetic coupling, a pneumatic coupling, a resilient locking coupling, or a friction-based coupling to provide a stable operating position for the arm. Magnetic couplings are preferred because the magnetic field decreases with the square of the distance. This means that when the magnet and the complementary ferromagnetic element are sufficiently far apart, the magnetic field does not impede the movement of the arm. However, when the magnet and the complementary ferromagnetic element are close to each other, the magnetic field applies a magnetic bias that causes the arm to orient toward a predefined operating position, thereby supplementing the resilient bias applied by the resilient coupling. This is particularly advantageous when the elastic coupling is not preloaded.

[0041] Preferably, the resilient coupling includes a resilient cap that surrounds the releasable rigid coupling. This protects the releasable rigid coupling from dust.

[0042] In this embodiment, the arm extends longitudinally along its axis. Preferably, the coupling mechanism includes a shape-fitting coupling that provides stable positioning of the arm in a predetermined angular position about the axis. The shape-fitting coupling can be releasable when the rigid coupling is released, and is configured to restore the predetermined angular position of the arm when the rigid coupling is engaged. It is understood that the shape-fitting coupling can also be configured to maintain the arm in the predetermined angular position of its axis even when the rigid coupling is released. This allows for more precise positioning of the arm and any devices that may be mounted on it. This is particularly advantageous in situations where a constant orientation of the device relative to an external target is required, such as in the case of ultrasonic sensors measuring the thickness of a tube. In this case, the shape-fitting coupling allows the ultrasonic sensor to maintain a constant orientation relative to the tube, thereby providing more reliable measurements.

[0043] In this embodiment, the attachment element includes a magnet and / or a suction cup. A magnet is advantageous when the external target is made of metal. A suction cup is advantageous when the external target has a non-porous surface.

[0044] Other preferred aspects are also defined in the appended claims and the following description. Attached Figure Description

[0045] The features and advantages of the present invention will become clear from the following detailed description of preferred embodiments of the invention, which are illustrated by way of non-limiting example with reference to the accompanying drawings, in which: Figure 1 This is a schematic diagram of a UAV according to the present invention; Figures 2 to 4 yes Figure 1 A schematic diagram of different locations of a UAV, which also includes an external protective cage. Figures 5 to 7 This is a detailed cross-sectional view of the UAV in the aforementioned figures; Figure 8 yes Figures 2 to 4 A side view of an implementation of a UAV; Referring to the accompanying drawings, the UAV (unmanned aerial vehicle) 1 according to an embodiment of the present invention includes a propulsion system 2, particularly a flight propulsion system; Figure 9 This is a graph showing the relationship between the restoring torque and angle of the coupling mechanism of a UAV according to an embodiment of the present invention. Detailed Implementation

[0046] The propulsion system 2 may include a frame 20, which preferably supports one or more rotating bodies 21. The rotating bodies may be controlled by a control system and may be powered by one or more batteries mounted on the frame 20. The rotating bodies may include one or more propellers, which are preferably driven by electric motors. Within the scope of the invention, the propellers may also be driven by other types of motors, such as combustion motors, and the energy may be provided in the form of, for example, liquid fuel. In a preferred embodiment, the propulsion system 2 may include three or four rotating bodies 21, for example, in a rectangular configuration, with the propellers controlled individually or in pairs to control the roll, yaw, and pitch angles of the UAV, enabling the UAV to fly or hover.

[0047] In the implementation method, such as Figures 2 to 4 As shown in the example, the propulsion system 2 includes an external protective cage 11. This external protective cage preferably defines two separate spaces, one inside the external protective cage and the other outside the external protective cage. The propulsion system frame 20 is preferably mounted inside the external protective cage. The external protective cage can be fixed to the propulsion system frame, preferably in a rigid manner.

[0048] Advantageously, the external protective cage 11 surrounds and protects the frame 20 and / or the rotating body 21 from impacts with external objects. To better absorb impact energy, the external protective cage 11 may include multiple interconnected beams 22 to form a polygonal grid or mesh-like structure, such as... Figure 8 As shown in the example. Furthermore, the external protective cage may have at least a partially rounded external shape, such as at least a partially elliptical, oval, spherical, or spherical external shape, such that the frame and / or rotating body is protected from all sides in the event of a collision with an external object. In an embodiment, the external protective cage may have a generally flat bottom to facilitate a stable landing.

[0049] Beams 22 can be connected together to form cage modules 23. The cage modules can have an outer pentagonal shape and can be fixed together in an interchangeable manner, particularly at the corners of their outer pentagonal shape, for example, by connectors 24. Connectors 24 can be permanently attached to the longitudinal ends of the beams, or, in a preferred embodiment, connectors 24 can be configured to allow removable connections between cage modules 23, such that the outer protective cage can be assembled from cage modules and can be at least partially disassembled. Assembly and disassembly of the cage modules facilitate the transport of the UAV by providing the outer protective cage as components, which are connected together before use, and disconnected in two or more components for packaging, storage, and transport. Disassembly of the cage modules 23 can also facilitate maintenance, for example, by replacing cage modules with broken beams, or by facilitating access to the frame 20 inside the outer protective cage.

[0050] The UAV may include a sensor system 17 coupled to the propulsion system 2. The sensor system 17 may include an image capture device, such as a video camera for capturing moving or still images, and the sensor system 17 may also include an illumination system specifically for projecting infrared or visible light onto the image capture device.

[0051] In this embodiment, the sensor system 17 is coupled to the frame 20. If an external protective cage 11 is present, it is preferable that the external protective cage has an opening through which the sensor system 17 protrudes, providing the sensor system with an unobstructed field of view in the wide-angle environment surrounding the UAV. Furthermore, the external protective cage 11 can be substantially flat in the area where the sensor system 17 protrudes through, further widening the sensor system's field of view.

[0052] Alternatively or additionally, the sensor system 17 may be coupled to the external protective cage 11 and may extend to the outside of the external protective cage. In one embodiment, the sensor support system 18 is fixed to the external protective cage 11, and the sensor system 17 may be coupled to the sensor support system 18.

[0053] Preferably, the UAV includes an arm 3. The arm 3 may be connected to the propulsion system 2, and more particularly to the frame 20 or the external protective cage 11. It is also preferred that the arm 3 extends away from the propulsion system 2, and more particularly from the frame 20 and (if present) the external protective cage 11. In an embodiment, the external protective cage 11 may have an opening allowing the arm 3 to protrude through it to the outside of the external protective cage. However, it is preferred that the arm is arranged outside the external protective cage (particularly entirely outside).

[0054] In one embodiment, arm 3 extends longitudinally along axis X from a first end 31 (which may be connected to the propulsion system) to a second end 32 (preferably opposite to the propulsion system). The position of arm 3 may be defined by the orientation of axis X. The longitudinal extension of arm along axis X is preferably straight, but may alternatively be at least partially curved or adjustable, for example, by one or more adjustable connectors. In other words, the arm may be hinged along its longitudinal extension by one or more adjustable connectors. The adjustable connectors advantageously allow the user to adjust the orientation or arrangement of the arm relative to the propulsion system to best suit the orientation of an external target surface or to bypass any obstacles between the UAV and the external target, thereby facilitating attachment in hard-to-reach locations.

[0055] Preferably, the second end 32 of the arm is arranged at the distal end of the arm outside the outer protective cage 11, such that the second end 32 of the arm is advantageously exposed to contact with an external target, while the outer protective cage 11 can be advantageously held at a distance from the external target. The external target may be, for example, the wall of a structure that the arm to be used inspects and / or manipulates.

[0056] The UAV may also include a releasable attachment element 4 connected to the arm 3 (particularly to the second end 32 of the arm) and configured to releasably attach to an external target. For example, the attachment element 4 may have an engagement surface configured to engage with the external target. In embodiments, the attachment element 4 includes one or more magnets 15, such as permanent magnets (particularly neodymium magnets) or electromagnets, preferably arranged flush with the engagement surface. Additionally or alternatively, the attachment element 4 may include a suction cup 16 configured to adhere to the surface of the external target using negative fluid pressure of air, thereby creating a partial vacuum.

[0057] Advantageously, the propulsion system 2 and the attachment element 4 are connected via a coupling mechanism 5. The coupling mechanism 5 is preferably located between the first end 31 of the arm and the propulsion system 2, and more particularly between the first end 31 and the frame 20 or the external protective cage 11. Alternatively, the coupling mechanism 5 may be located between the second end 32 of the arm and the attachment element 4.

[0058] like Figure 5 and Figure 6 As shown in the example, the coupling mechanism 5 preferably includes a releasable rigid coupling 6. Advantageously, the releasable rigid coupling 6 provides stable rigid positioning of the arm 3 in a predefined operating position Pos1. Additionally, advantageously, the releasable rigid coupling 6 is releasable when the UAV is attached to an external target, provided a torque T greater than a predetermined threshold T1 is applied. The releasable rigid coupling 6 can be based on various coupling mechanisms, including magnetic, electromagnetic, pneumatic, elastically engaging, or friction-based coupling mechanisms, to provide a stable operating position for the arm 3. Releasing the rigid coupling 6 allows the attachment element 4 to move relative to the propulsion system 2 with at least two or three degrees of freedom.

[0059] Preferably, the coupling mechanism 5 further includes a resilient coupling 7 that applies a resilient bias, causing the arm 3 to move toward a predefined operating position Pos1. The resilient coupling 7 is configured to allow the propulsion system 2 to move relative to the attachment element 4 against the resilient bias when the rigid coupling 6 is released, and to restore the rigid coupling when the UAV disengages from an external target. The resilient coupling 7 can have various configurations depending on the implementation. For example, it may include one or more rubber joints, elastic bands (e.g., rubber strips), and / or springs (e.g., tension springs, compression springs, torsion springs, or constant force springs).

[0060] In one embodiment, the coupling mechanism 5 includes a first coupling end 51 and a second coupling end 52, which may have a flange shape. The first coupling end 51 and the second coupling end 52 can be releasably coupled to each other to advantageously provide stable rigid positioning of the arm 3 in a predefined operating position Pos1. When the first coupling end 51 and the second coupling end 52 are coupled to each other, they are preferably aligned along the axis X. The first coupling end 51 and the second coupling end 52 can be releasable when a torque T greater than a predetermined threshold T1 is applied. In a preferred embodiment, the first coupling end 51 is connected to the propulsion system 2, while the second coupling end 52 is connected to the arm 3 and preferably coincides with the first end 31 of the arm. Alternatively, the first coupling end 51 may be connected to the arm 3 and may coincide with the second end 32 of the arm, while the second coupling end 52 may be connected to the attachment element 4.

[0061] In one embodiment, the releasable rigid coupling 6 includes a magnetic coupling 12. The magnetic coupling 12 may include a pair of magnets 19, particularly permanent magnets such as neodymium magnets. Preferably, one magnet is fixed to a first coupling end 51, and the other magnet is fixed to a second coupling end 52. It is understood that, in one embodiment, a ferromagnetic element having a ferromagnetic material (e.g., an iron alloy) may be used instead of one of the two magnets. The magnetic coupling 12 can be readily adapted to different loads and exhibits rigidity within a threshold given by the magnetic force of the magnets 19. When this threshold is exceeded, the resilient coupling 7 can undergo large deformation without failing due to overload. Advantageously, the resilient bias applied by the resilient coupling 7 increases linearly with the deformation of the resilient coupling.

[0062] In one embodiment, the resilient coupling 7 includes a resilient cap 13, which preferably surrounds the releasable rigid coupling 6. The resilient cap 13 may be made of an elastomer, such as a polymeric elastomer or rubber material. The resilient cap 13 may have a tubular shape, which preferably includes a middle section 33 positioned between two opposing end sections 34. In one embodiment, the tubular shape tapers from the middle section 33 toward the end sections 34. The end sections 34 of the resilient cap may be attached, for example, to the first coupling end 51 and the second coupling end 52, respectively, via zip-ties 35. The releasable rigid coupling 6 may be arranged in the region of the middle section 33 of the resilient cap. The middle section 33 may be configured to elastically deform upon release of the rigid coupling 6, such as… Figure 6 As shown in the example.

[0063] like Figure 6 As shown in the example, arm 3 is preferably configured to form an angle A relative to its predefined operating position Pos1 when the rigid coupling 6 is released. Specifically, angle A can refer to the angular displacement of the arm's axis X from its predefined operating position Pos1 about the coupling mechanism 5. Accordingly, the coupling mechanism 6 is preferably configured to apply a torque T that tends to restore the rigid coupling 6, or in other words, tends to restore the predefined operating position Pos1.

[0064] Preferably, the restoring torque T varies with angle A, as shown in the reference... Figure 9 The following example of the curve is illustrated.

[0065] In this embodiment, the restoring torque T has two components: a magnetic restoring torque (generated specifically by the magnetic coupling 12) and a resilient restoring torque (generated specifically by the resilient coupling 7). Therefore, the total restoring torque T can be given by the sum of the magnetic and resilient restoring torque components. Advantageously, the magnetic restoring torque is maximized at the predefined operating position Pos1 and can decrease with increasing angle A. Conversely, the resilient restoring torque is advantageously minimized at the predefined operating position Pos1 and can increase with increasing angle A. In this embodiment, the resilient restoring torque is essentially zero at the predefined operating position Pos1. Alternatively, the resilient coupling 7 can be preloaded, thus providing some resilient restoring torque even at the predefined operating position Pos1.

[0066] In the predefined operating position Pos1, the coupling mechanism 5 can apply a restoring torque T, which has a predetermined threshold T1. In the implementation (possibly depending on the preload of the elastic coupling 7), the predetermined threshold T1 is given solely by or primarily by the magnetic restoring torque component. When the rigid coupling 6 is released, or in other words, when the arm 3 shifts away from the predefined operating position Pos1, the angle A can increase, and the restoring torque T can decrease accordingly until it falls below a second threshold T2 below the predetermined threshold T1. In this case, if the angle A continues to increase, the restoring torque T may subsequently increase above the second threshold T2 due to the increase in the elastic restoring torque component.

[0067] Advantageously, propulsion system 2 has sufficient authority to overcome a predetermined threshold T1, or in other words, propulsion system 2 is configured to apply a propulsive torque greater than the predetermined threshold T1. This allows the rigid coupling 6 to be released when attachment element 4 is attached to an external target.

[0068] Advantageously, the second threshold T2 is higher than the torque applied to the coupling mechanism 5 by the weight of the components supported by the coupling mechanism 5 (e.g., the weight of the arm 3, attachment element 4, device 8, etc.) when the attachment element 4 detaches from the external target. This allows the coupling mechanism 5 to apply sufficient torque to restore the predefined operating position Pos1 when detached from the external target.

[0069] Advantageously, the predefined operating position Pos1 of the arm allows the arm to aim at an external target while maintaining the propulsion system 2 at a safe distance from the external target. The predefined operating position Pos1 of the arm can be selected based on the location and orientation of the external target that needs to be reached by the arm. For example, the arm 3 in the predefined operating position Pos1 can be as follows: Figure 1 The example shows an upward / forward extension of propulsion system 2, or as shown in the example. Figure 2The example shows an extension downwards from the propulsion system 2. In an embodiment, the arm 3 may be connected to the portion of the external protective cage 11 located below the frame 20 (e.g., Figure 2 and Figure 3 As shown in the example), or connected to the portion of the external protective cage 11 located above the frame 20 (such as... Figure 3 (As shown in the examples). It is understood that each of these constructions facilitates attachment to different types of external targets, including vertical walls, downward-facing surfaces (such as ceilings), or upward-facing surfaces (such as floors).

[0070] When the rigid coupling 6 is released, the arm 3 can move away from the predefined operating position Pos1, allowing the propulsion system 2 to move freely to another position Pos2 relative to the arm, such as... Figure 2 and Figure 3 As shown in the example.

[0071] Another advantage of the connecting mechanism 5 is its ability to overcome obstacles by reversibly reducing the overall size of the arm upon impact. For example... Figure 4 As illustrated in the example, a UAV might have to fly over a manhole smaller than the overall size of the UAV, including the arm in the predefined operating position Pos1. However, when the arm strikes the edge of the manhole, the coupling mechanism 5 allows the arm to move away from the predefined operating position Pos1 towards another position Pos2 closer to the propulsion system. This allows the UAV to fly over the manhole. Once the obstacle is overcome, the coupling mechanism 5 automatically returns the arm to the predefined operating position Pos1. Understandably, this capability is advantageous for navigation in cluttered environments. Furthermore, this capability allows the UAV to be transported in a compact container.

[0072] Another advantage provided by the coupling mechanism 5 is that the UAV can take off and land more stably because the arm 3 can be reversibly moved away from the predefined operating position Pos1 when the arm may be exposed to contact with the landing surface (e.g., when the arm is coupled to the portion of the external protective cage 11 located below the frame 20).

[0073] In the implementation method, such as Figure 7As illustrated in the example, the coupling mechanism 5 includes a shape coupling 14 (e.g., a Hirth coupling) configured to hold the arm 3 in a predetermined angular position about the axis X. The shape coupling 14 may include conjugate tooth profiles formed on a first coupling end 51 and a second coupling end 52, respectively. The conjugate tooth profiles may include corresponding teeth extending along the axis X and configured to engage with each other to prevent relative rotation of the first and second coupling ends about the axis X of the arm. The shape coupling 14 may be configured to hold the arm 3 in the predetermined angular position about the axis X at least when the releasable rigid coupling 6 is engaged, and preferably even when the rigid coupling is released. For this purpose, one of the coupling ends may include an outer edge 53 protruding around the other coupling end to keep the two coupling ends centered relative to each other.

[0074] The UAV may also include a device 8 mounted on the arm 3 and configured to inspect and / or manipulate an external target when the arm is attached to it. The device 8 may be operably connected to the propulsion system 2, for example via cable, for power and / or signal transmission. Undesirable twisting of the cable around the arm 3 can be avoided due to the shape of the coupling 14.

[0075] In an embodiment, the device 8 includes a sensor 9, preferably a non-destructive testing (NDT) sensor, particularly for non-destructive testing of structures. For example, the sensor 9 may be adapted to measure the thickness of the structure under test or to sense defects in the structure. The sensor 9 may be configured to transmit a measurement signal and receive a return signal in response to the measurement signal. The transmitted measurement signal may be influenced by the material of the structure under test to provide a return signal representing the physical state of the structure.

[0076] In one embodiment, sensor 9 has an operating surface configured to contact the surface of an external target to perform a measurement thereon. In a preferred embodiment, sensor 9 includes an ultrasonic sensor, such as a contact ultrasonic sensor, particularly for measuring thickness. As used herein, the term "contact ultrasonic sensor" preferably refers to a sensor capable of performing ultrasonic detection solely through direct or indirect contact between the sensor and the structure being inspected. Additionally or alternatively, sensor 9 may include an eddy current sensor, an electromagnetic acoustic transducer, or an NDT scanner.

[0077] In one embodiment, the device 8 may also include a cleaning tool for cleaning a portion of the structure to be detected by the sensor 9 (particularly an ultrasonic sensor). This allows for more accurate measurements. The cleaning tool may include, for example, a rotating brush (e.g., a wire brush or abrasive brush) or a cleaning pad (e.g., an abrasive cleaning pad).

[0078] In the implementation method, such as Figure 8 As illustrated in the example, device 8 may also include a couplant dispensing nozzle 81 for delivering couplant to sensor 9. This is particularly advantageous when the sensor includes an ultrasonic sensor. The UAV may also include a couplant dispensing system 82 mounted inside an external protective cage 11 and a piping system 83 for fluidly connecting the couplant dispensing system 82 to the couplant dispensing nozzle 81. The piping system may be flexible to allow movement of arm 3. Undesirable twisting of the piping system 83 around the arm can be avoided due to the shape of the coupling 14. The couplant dispensing system 82 may include a couplant reservoir and a pump fluidly connected to the reservoir for delivering couplant from the reservoir to the couplant dispensing nozzle 81. As used herein, the term "couplant" preferably refers to a fluid medium that facilitates sound transmission between sensor 9 and the external target to be inspected.

[0079] In one embodiment, the UAV includes at least one mounting support 90, which is fastened to an external protective cage 11 and advantageously configured to receive a first end 31 of an arm or a first connecting end 51 of a coupling mechanism. The at least one mounting support 90 can be reversibly fastened to the external protective cage 11. The first end 31 or the first connecting end 51 can be reversibly attached to the at least one mounting support 90.

[0080] In one embodiment, the arm 3 or the connecting mechanism 5 is hinged to the at least one mounting support 90, for example, around a pin connection positioned between the mounting support 90 and the first end 31 or the first connecting end 51. This hinge advantageously allows the arm 3 to be oriented toward a surface of an external target, whether the surface of the external target is vertical, inclined, or horizontal. In another embodiment, the UAV may include an actuator, such as an electric motor, configured to adjust the orientation of the arm 3 around the hinge of the mounting support 90.

[0081] The UAV may include a plurality of mounting supports 90 fastened to an external protective cage 11. Preferably, the mounting supports 90 are fastened to the external protective cage 11 at correspondingly spaced fastening portions. Also preferably, the arm 3 or the connecting mechanism 5 is interchangeably connected to a freely selectable or optional mounting support 90 from the plurality of mounting supports. The possibility of connecting the arm 3 or the connecting mechanism 5 to any one of the mounting supports 90 advantageously allows the arm 3 to be positioned in a spatial orientation most suitable to the surface of the external target.

[0082] In embodiments, particularly if the coupling mechanism 5 is positioned between the propulsion system 2 and the arm 3, the UAV may further include a flexible coupling 10 positioned between the arm 3 and the attachment element 4. Preferably, the flexible coupling 10 extends longitudinally along the arm 3. Figure 8 As illustrated in the example, the flexible coupling 10 may include a spring coupling. Alternatively or additionally, the flexible coupling 10 may include a second coupling mechanism that may have the same or similar features as the coupling mechanism 5 used to connect the arm 3 to the propulsion system 2. Advantageously, the flexible coupling 10 allows the attachment element 4 to move relative to the arm 3 according to at least two or three degrees of freedom. The degrees of freedom released by the flexible coupling 10 increase the degrees of freedom released by the coupling mechanism 5, allowing the propulsion system 2 to tilt about its center of gravity G, thereby improving flight control when attached to an external target. Furthermore, the flexible coupling 10 facilitates the establishment of stable contact between the attachment element and the external target when the UAV approaches the external target from any angle relative to the horizontal or vertical plane.

Claims

1. A UAV (1) that can be attached to an external target, the UAV comprising: Propulsion system (2); Arm (3), which extends away from the propulsion system; and a releasable attachment element (4), the releasable attachment element being connected to the arm and configured to be releasably attached to the external target, wherein the propulsion system and the attachment element are coupled via a coupling mechanism (5), the coupling mechanism (5) being positioned between the arm and the propulsion system or between the arm and the attachment element, the coupling mechanism comprising: - A releasable rigid coupling (6) provides stable rigid positioning of the arm in a predefined operating position (Pos1), and is releasable when the UAV is attached to the external target, provided that a torque (T) greater than a predetermined threshold (T1) is applied. - A resilient coupling (7) that applies a resilient bias that causes the arm to move toward the predefined operating position (Pos1), and the resilient coupling is configured to: allow the propulsion system to move relative to the attachment element against the resilient bias when the rigid coupling is released, and to restore the rigid coupling when the UAV disengages from the external target.

2. The UAV of claim 1, wherein the UAV includes a device (8) mounted on the arm and configured to inspect and / or manipulate the external target when the arm is attached to the external target.

3. The UAV according to claim 2, wherein, The device includes a sensor (9), preferably an ultrasonic sensor.

4. The UAV according to any one of the preceding claims, wherein, The coupling mechanism is located between the propulsion system and the arm, and the UAV also includes a flexible coupling (10) located between the arm and the attachment element.

5. The UAV according to any one of the preceding claims, wherein, The propulsion system includes an external protective cage (11), the arm being connected to the external protective cage and extending to the outside of the external protective cage.

6. The UAV according to claim 5, wherein, The connecting mechanism is positioned between the external protective cage and the arm.

7. The UAV according to any one of the preceding claims, wherein, The releasable rigid coupling includes a magnetic coupling (12).

8. The UAV according to any one of the preceding claims, wherein, The resilient coupling includes a resilient cap (13) that surrounds the releasable rigid coupling.

9. The UAV according to any one of the preceding claims, wherein, The arm extends longitudinally along an axis (X), and the connecting mechanism includes a shape connector (14) that provides stable positioning of the arm in a predefined angular position around the axis.

10. The UAV according to any one of the preceding claims, wherein, The attachment elements include a magnet (15) and / or a suction cup (16).

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