It should be noted that the figures are not drawn to scale and that elements of similar structures or functions are generally represented by like reference numerals for illustrative purposes throughout the figures. It also should be noted that the figures are only intended to facilitate the description of the preferred embodiments. The figures do not illustrate every aspect of the described embodiments and do not limit the scope of the present disclosure.
The invention generally relates to vertical takeoff and landing (VTOL) aircraft and other aircraft, such as drones, with protective cages. Some inspection drones can include protective cages so they can operate in close proximity to fixed objects under inspection and nearby structures without inflicting or incurring damage. Some drones for inspection of fixed objects have cages that are purely protective and do not provide any aerodynamic lift, and such cages can hurt rather than enhance flight efficiency. There is a need in the art to maximize, optimize, and improve the aerodynamic performance of drones with protective cages.
Various embodiments include a VTOL, hover-capable multirotor aircraft with a structure surrounding the rotors that acts as a protective cage and functions as an annular wing in forward flight. Such an aircraft in some examples can take off and land using the thrust of the rotors like a drone multirotor. Once airborne, the aircraft can pitch to a nearly-horizontal attitude and fly supported by the aerodynamic lift of the annular wing. The rotors can then propel the aircraft forward only, thus reducing the power required to fly as compared to flying like a rotorcraft being supported by motor/rotor thrust. In slow-speed rotor-borne flight, the annular wing can act to protect the rotors from contact with obstacles, thus allowing the aircraft to operate in very close proximity to fixed objects.
Various embodiments can provide a VTOL, hover-capable multirotor aircraft with a structure surrounding the rotors that acts as a protective cage and functions as an annular wing in forward flight. A multirotor aircraft, such as a multirotor drone, can provide powered lift, propulsion and control; and an annular wing structure can provide lift in forward flight and can protect the rotors from contact with obstacles when the aircraft is operating in close proximity to fixed objects or moving.
In various embodiments, a multirotor drone or unstaffed aerial vehicle (UAV) can be attached by struts to a surrounding cage/wing assembly. The multirotor UAV can be comprised of a UAV structure on which are mounted rotors driven by motors, and a sensor payload. The UAV, including rotors, can be entirely inside of the cage/wing in some examples, which can have the form of a cylinder or polygon in some embodiments. Tube or rod cage members connected by junctions can provide structural support of the cage, which can have an open top bumper assembly, an open bottom, and sides with a continuous skin or skins to form an annular wing. The wing skins may be transparent or translucent to allow the UAV's sensors to see through the wing (e.g., via visual spectrum light, light above or below such a spectrum, or the like).
The cage/wing can act to protect the rotors when operating close to objects, and thus the cage/wing structure in various embodiments can be resilient enough to withstand at least low-speed collisions with objects. The wing can provide lift and can improve efficiency in translating flight. The lift of the wing can support the weight of the aircraft, allowing the rotors to produce less thrust than if they were needed to support the aircraft's weight. The annular wing defined by a cage/wing can have a variety of forms (e.g., cylindrical, or a polygonal prism) and may have an airfoil cross-section, flat cross-section, or the like.
Turning to
In various embodiments, the aircraft 110 can be a drone or UAV comprising an aircraft body 112 with a plurality of arms 114 extending from the body 112 with rotors 116 at terminal ends of the arms 114. The aircraft 110 can comprise one or more sensors 118 such as a camera, LIDAR, ultrasonic range sensor, microphone, accelerometer, GPS, gyroscopic sensor, compass, and the like. Such sensors 118 can be located on various locations on the aircraft 110 including grouped together as a sensor payload or disposed separately about the aircraft 110. In various embodiments, such sensors can be absent from the cage assembly 120, but in some embodiments, the cage assembly 120 can comprise various suitable sensors 118. For example, one or more cameras can be coupled to one or more of the truss bars 132. Also, in various embodiments, one or more sensors 118 can be coupled to the aircraft 110 within the cage cavity 140, but can be configured to have a line of sight above or below the wing body 160. For example, in some embodiments, a camera can be disposed at the end an elongated shaft of sufficient length that the camera has visibility over the top ring 130 and the wing body 160.
While various embodiments herein include a quadrotor aircraft 110, any suitable aircraft 110 can be used in various embodiments including drones or UAVs with any suitable number and type of propulsion systems, such as motors, engines, or the like. An aircraft 110 of various embodiments can be any suitable size and can be an unstaffed aerial vehicle (UAV), can be piloted, can be remotely piloted or can be fully or partially autonomous. For example, in some embodiments, the aircraft 110 can comprise a cockpit where one or more human users can operate the aircraft 110 or such a cockpit can be specifically absent in some embodiments.
Also, in various embodiments, the aircraft 110 can be removably coupled to the cage assembly 120 via one or more struts 150 or can be operable without the cage assembly 120 being present. However, in some embodiments, the aircraft 110 can be integrally coupled to the cage assembly 120 or the aircraft 110 can be inoperable without the cage assembly 120 being present. Also, while various examples herein include four struts 150, further embodiments can include any suitable number of struts 150 or other suitable elements that couple the body 112 of the aircraft 110 to the cage assembly 120.
In various embodiments, the cage assembly 120 can include a hollow octagonal prism defined by octagonal top and bottom rings 134, 136 of the same size and shape with eight sidebars 138 of the same length extending in parallel between the top and bottom rings 134, 136 and the wing body 160 surrounding the sidebars 138 to define the open top and bottom cavity ends 142, 144 of the cage cavity 140. The cage assembly 120 can have eight planes of symmetry about a central axis X of the aircraft assembly 100.
However, in further embodiments, the cage assembly can include various suitable hollow shapes such a circular or oval cylinder; triangular prism, rectangular prism, square prism, pentagonal prism, hexagonal prism, heptagonal prism, octagonal prism, nonagonal prism, decagonal prism, and the like. Also, while various embodiments include parallel sidewalls of cage assembly 120 defined by the wing body 160, some embodiments can include tapered sidewalls based on the diameters of the top and bottom rings 134, 136 being different sizes. Also, in some embodiments, the sidewalls can be concave, convex or other suitable shape with the top and bottom rings 134, 136 being the same or different sizes.
In some embodiments, the cage assembly 120 can be large (e.g., with a maximum diameter of 50 m, 40 m, 30 m, 20 m, or the like or a range between such values) or can be smaller (e.g., with a maximum diameter of 1 ft, 2 ft, 3 ft, 4 ft, 5 ft, 6 ft, 7 ft, 8 ft, 9 ft, 10 ft, 12 ft, 15 ft, 20 ft, 25 ft, 30 ft, 35 ft, 40 ft, 45 ft, 50 ft, 55 ft, or the like or a range between such values). One preferred embodiment has a cage assembly 120 with a diameter of 14 inches.
As shown in the examples of
In various embodiments, the top ring 134 and/or bottom ring 136 can comprise a plurality of bars, rods or tubes that are joined together in various ways, including via a fitting 700 (see e.g.,
In various embodiments, the wing body 160 can include various suitable materials, structures, profiles, shapes, or the like. For example,
In some embodiments, rods, tubes or bars of the top and bottom rings 134, 136 are connected by a flexible thin membrane skin having a thickness of 5-10 millimeters; however, further embodiments can have a membrane skin of any suitable thickness. Such a membrane skin can comprise various suitable materials such as a plastic film (e.g., mylar, vinyl or polyethylene), woven fabric, or the like. In various embodiments, such a membrane skin can be impervious to air passing through the membrane skin, can resist air passing through the membrane skin, or the like. Such an air-impact can be a based on an inherent property of such a material or such a material can be treated to generate such a property.
In some embodiments, such as shown in
In some embodiments, such as shown in
In some embodiments, the wing body 160 can be a rigid structural element of the cage assembly 120. In some such embodiments, elements such as sidebars 138, the top ring 134 and/or bottom ring 136 can be absent or can be defined by a portion of the wing body 160. For example, a top ring 134 can be defined by a leading edge of the wing body 160 and a bottom ring can be defined by a trailing edge of the wing body 160.
The aircraft assembly 100 can be configured to carry various payloads. For example, in some embodiments, a payload body can be attached to the cage assembly 120 by struts 150 and/or additional propulsive elements for translating flight can be added. The motor configuration of an aircraft 110 or other propulsion element can be either tractor or pusher, and the motors of such an aircraft 110 or propulsion element may be any suitable type, such as an internal combustion engine (“ICE”), electric or the like. Ducted fans could be used instead of or in addition to or as an alternative to propellers in some embodiments. In various examples, batteries or fuel tanks can be mounted to the cage assembly 120 (e.g., within the cage cavity 140, external to the cage cavity 140, or the like).
The aircraft assembly 100 and components thereof or utilized in the various embodiments of the aircraft assembly 100 may be constructed using any suitable method and a variety of suitable materials. The cage 130 and wing body 160 may be constructed using any suitable method and a variety of suitable materials. Some or all of the cage 130 may be fabricated of pre-cured composite (e.g., carbon fiber, fiberglass or other fiber) rods or tubes cut to proper length. Other materials, including aluminum alloy tubing or wood dowels may also be used to fabricate some or all of the cage 130. The cage 130 in some embodiments can be fabricated of complex molded plastic parts that form some or all of the cage 130.
In various embodiments, the aircraft assembly 100 takes off and lands vertically under the thrust of rotors 116 of an aircraft 110 of the aircraft assembly 100, but can transition into a flight orientation by pitching over horizontally for wing-borne flight supported by lift generated by the wing body 160 (e.g., having an airfoil configuration). The cage assembly 130 can protect the rotors 116 from contacting obstacles, which can allow the aircraft assembly 100 to safely fly either rotor-borne and/or wing-borne in close proximity to fixed objects (e.g., walls, posts, fences, and the like) or in close proximity to moving objects (e.g., other aircraft assemblies 100, other aircraft 110, vehicles, birds, people, or the like). For example, the cage assembly 130 can generate lift and can also be strong enough to withstand bumping or crashing into objects such that the cage assembly 130 does not collapse and contact one or more of the rotors 116 to cause failure of the aircraft (e.g., an impact force of at least 50 kN, 100 kN, 500 kN, 1000 kN, 2000 kN, 3000 kN or the like).
When airborne, the aircraft assembly 100 can rotate to a horizontal configuration for flight with the truss bars 132 and top ring 134 oriented forward and being the leading edge of flight, with the bottom ring 136 being the trailing edge during flight. The aircraft assembly 100 can be configured to fly with an angle of attack at various suitable horizontal angles relative to true horizontal (e.g., where main axis X of the aircraft assembly 100 is parallel to the ground or perpendicular to gravity) such as −20°, −15°, −10°, −9°, −8°, −7°, −6°, −5°, −4°, −3°, −2°, −1°, 0°, 1°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, 10°, 5°, 20° or the like, or a range between such values. In one preferred embodiment, the angle of attack is between 5° and 10°.
In various embodiments, the rotors 116 of the aircraft 110 generate forward propulsion for forward flight of the aircraft assembly 100 with the wing body 160 generating aerodynamic lift for the aircraft assembly 100 based on forward flight in the horizontal flight orientation. The aerodynamic lift generated by the wing body 160 can support the weight of the aircraft assembly 100 and can thereby reduce power required to fly in the horizontal configuration compared to power that would be required for forward flight of the aircraft assembly 100 in the vertical orientation. For example, in various embodiments, aerodynamic lift generated by the wing body 160 can support various amounts of the weight of the aircraft assembly 100 including at least 60%, 70%, 80%, 85%, 90%, 95%, 100%, 110%, 120%, 130% or the like, or a range between such example values.
For landing, the aircraft assembly 100 can rotate from the horizontal configuration to a vertical orientation with the truss bars 132 and top ring 134 oriented upward and the bottom ring 136 oriented downward (where main axis X of the aircraft assembly 100 is perpendicular to the ground or parallel to gravity). The aircraft assembly 100 can land on the ground or other surface via the bottom ring 136, landing gear on the bottom ring 136, or the like. Propulsive upward force for landing can be generated by the rotors 116 of the aircraft 110, and in various embodiments, exclusively by the rotors 116 of the aircraft 110.
The described embodiments are susceptible to various modifications and alternative forms, and specific examples thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the described embodiments are not to be limited to the particular forms or methods disclosed, but to the contrary, the present disclosure is to cover all modifications, equivalents, and alternatives. Additionally, elements of a given embodiment should not be construed to be applicable to only that example embodiment and therefore elements of one example embodiment can be applicable to other embodiments. Additionally, elements that are specifically shown in example embodiments should be construed to cover embodiments that comprise, consist essentially of, or consist of such elements, or such elements can be explicitly absent from further embodiments. Accordingly, the recitation of an element being present in one example should be construed to support some embodiments where such an element is explicitly absent.
This application is a non-provisional of and claims the benefit of U.S. Provisional Application No. 63/293,805, filed Dec. 26, 2021, entitled “VERTICAL TAKE-OFF AND LANDING (VTOL) AIRCRAFT WITH AERODYNAMICALLY LIFTING PROTECTIVE STRUCTURE.” This application is hereby incorporated herein by reference in its entirety and for all purposes.
Number | Date | Country | |
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63293805 | Dec 2021 | US |