Patent Description:
In recent years, unmanned aerial vehicles (UAVs) or drones have been used to fly significant distances to transport payloads (e.g., packages, supplies, equipment, etc.) or gather information. Some UAVs land on runways while others are captured in flight by UAV recovery systems. Capturing UAVs without the use of a runway enables greater flexibility in recovery locations. In particular, a UAV can be recovered in an unprepared area or on relatively smaller ships or other vessels or vehicles.

<CIT> states in its abstract: "a method of launching and retrieving a UAV (Unmanned Aerial Vehicle). The preferred method of launch involves carrying the UAV up to altitude using a parasail similar to that used to carry tourists aloft. The UAV is dropped and picks up enough airspeed in the dive to perform a pull-up into level controlled flight. The preferred method of recovery is for the UAV to fly into and latch onto the parasail tow line or cables hanging off the tow line and then be winched back down to the boat.

<CIT> states in its abstract: "a parasail-assisted system for launching a fixed-wing aircraft into free flight and for retrieving a fixed-wing aircraft from free flight.

<CIT> states in its abstract: "a method and apparatus for retrieving an aircraft in a confined space involves hanging a cable, for example from a kite or mast, across the aircraft's flight path. The aircraft approaches the cable in steady forward flight, and may strike the cable at any point on the wing, fuselage, or other leading surface. The cable then slides along the airframe as the aircraft moves forward, until it is intercepted by a hook attached to the wing tip or other convenient location. The hook captures the cable, and prevents further sliding; the cable then pulls the aircraft to a stop. Compliance of the cable, optionally combined with compliance of the cable suspension, provides acceptably gradual deceleration. The aircraft is left suspended in mid-air, and is then winched or slid to the base of the cable or other convenient retrieval point. The cable suspension and other fixed objects can be kept well clear of the flight path, so that the aircraft can continue safely in the event that it misses the cable, and make another approach.

<CIT> states in its abstract: "methods and apparatuses for launching and capturing unmanned aircraft and other flight devices or projectiles are described. " "The aircraft can be launched from an apparatus that includes an extendable boom. The boom can be extended to deploy a recovery line to retrieve the aircraft in flight. The aircraft can then be retrieved from the recovery line. The boom can be retracted when not in use to reduce the volume it occupies.

<CIT> states in its abstract: "methods and apparatus to deploy unmanned aerial vehicles (UAVs) by kites are disclosed. An example apparatus to deploy a UAV includes a tether line to support the UAV, a tensioner operatively coupled to the tether line, and a kite operatively coupled to the tether line to support the tether line for deployment of the UAV.

<CIT> states in its abstract: "methods and apparatus to recover unmanned aerial vehicles (UAVs) with kites are disclosed. A disclosed example apparatus to recover a UAV during flight includes a tether line, a tensioner operatively coupled to the tether line, and a kite operatively coupled to the tether line to support the tether line for recovery of the UAV.

In a first aspect, an apparatus to recover an aircraft is provided according to claim <NUM>. Optional features are set out in claims <NUM> to <NUM>.

In a second aspect, a method to recover an aircraft is provided according to claim <NUM>. Optional features are set out in claims <NUM> to <NUM>.

The figures are not to scale. Instead, the thickness of the layers or regions may be enlarged in the drawings. In general, the same reference numbers will be used throughout the drawing(s) and accompanying written description to refer to the same or like parts. As used herein, unless otherwise stated, the term "above" describes the relationship of two parts relative to Earth. A first part is above a second part, if the second part has at least one part between Earth and the first part. Likewise, as used herein, a first part is "below" a second part when the first part is closer to the Earth than the second part. As noted above, a first part can be above or below a second part with one or more of: other parts therebetween, without other parts therebetween, with the first and second parts touching, or without the first and second parts being in direct contact with one another. As used in this patent, stating that any part is in any way on (e.g., positioned on, located on, disposed on, or formed on, etc.) another part, indicates that the referenced part is either in contact with the other part, or that the referenced part is above the other part with one or more intermediate part(s) located therebetween. As used herein, connection references (e.g., attached, coupled, connected, and joined) may include intermediate members between the elements referenced by the connection reference and/or relative movement between those elements unless otherwise indicated. As such, connection references do not necessarily infer that two elements are directly connected and/or in fixed relation to each other. As used herein, stating that any part is in "contact" with another part is defined to mean that there is no intermediate part between the two parts.

Unless specifically stated otherwise, descriptors such as "first," "second," "third," etc. are used herein without imputing or otherwise indicating any meaning of priority, physical order, arrangement in a list, and/or ordering in any way, but are merely used as labels and/or arbitrary names to distinguish elements for ease of understanding the disclosed examples. " In such instances, it should be understood that such descriptors are used merely for identifying those elements distinctly that might, for example, otherwise share a same name. As used herein, "approximately" and "about" refer to dimensions that may not be exact due to manufacturing tolerances and/or other real world imperfections.

Methods and apparatus to recover unmanned aerial vehicles (UAVs) with kites are disclosed. Some UAVs are recovered by recovery systems, which employ a recovery tether line that is suspended vertically. In particular, a UAV contacts and/or impacts the tether line and, as a result, the UAV is decelerated and/or stopped from flight, thereby enabling recovery of the UAV without need for a runway. In some known implementations, a parachute or support beam is used to suspend the tether line for recovery of the UAV.

Examples disclosed herein enable highly controlled and cost-effective recovery of an aircraft (e.g., a UAV) via a stationary platform or a moving vehicle or vessel (e.g., a ship, etc.). Examples disclosed herein enable aircraft to be recovered without a significant amount of force and/or stress imparted to the aircraft. As a result, examples disclosed herein can enable aircraft that do not require significant structural components that can be costly and have a significant amount of weight.

Examples disclosed herein include a kite that supports a tether line. The tether line extends between a mast and a base. Further, the tether line is guided by boom that extends from the mast. When an aircraft is being recovered, the aircraft is brought into contact with a portion of the tether line that extends between an end of the boom (e.g., a distal end of the boom) and the base. The aircraft is decelerated by the tether line causing movement of the kite and, thus, dissipating kinetic energy of the aircraft. As a result, the aircraft encounters reduced impact and deceleration forces in contrast to known recovery systems. According to some examples disclosed herein, the portion of the tether line is positioned on a first side of the boom while the kite is positioned on a second side of the boom opposite the first side (e.g., the portion of the tether line is positioned below the boom while the kite is positioned above the boom).

In some examples, the tether line is guided through a fixed point (e.g., a fixed point loop or ring) of the aforementioned boom. In some examples, the tether line is coupled to the kite via an alpine butterfly knot of the tether line (e.g., positioned on the tether line). In some examples, a brake is implemented to decelerate the tether line and, in turn, the aircraft subsequent to the aircraft impacting the tether line. Additionally or alternatively, a spring is implemented to dampen movement of the tether line, the boom and/or the kite. In some examples, the boom is telescoping and/or an angle of the boom can be adjusted to vary an amount of deceleration imparted to the aircraft during recovery thereof. In some examples, kites coupled to the tether line are interchangeable and/or selectable for different kite configurations, aircraft configurations and/or kite recovery requirements.

<FIG> depicts an unmanned aerial vehicle (UAV) recovery system <NUM> in accordance with teachings of this disclosure. The UAV recovery system <NUM> of the illustrated example is implemented to recover an aircraft <NUM> and includes a base <NUM>, a mast <NUM>, a boom <NUM>, and a tether line <NUM>. In this example, the boom <NUM> includes a first end (e.g., a proximal end) <NUM> at the mast <NUM> and a second end (e.g., a distal end) <NUM> of the boom <NUM> that is opposite the first end <NUM>. The tether line <NUM> of the illustrated example extends from the mast <NUM> to the base <NUM>, and is guided by the boom <NUM>. Further, a first portion <NUM> of the tether line <NUM> extends from the base <NUM> and/or the ground associated with the base <NUM> to the second end <NUM> for contact with the UAV <NUM> while a second portion <NUM> of the tether line <NUM> extends between the second end <NUM> and the mast <NUM> to constrain/guide the tether line <NUM>. In the illustrated example, a kite <NUM> is shown with at least one support line <NUM> coupled to the tether line <NUM> at or proximate the second end <NUM>. Further, the example kite <NUM> is depicted deployed above the mast <NUM> as well as the boom <NUM>. As will be discussed in greater detail below in connection with <FIG>, in this example, the kite <NUM> is coupled to the tether line <NUM> to dissipate energy during impact of the UAV <NUM> with the tether line <NUM>. In other examples, the tether line <NUM> extends above the boom <NUM> to the kite <NUM> (e.g., the tether line <NUM> extends to the kite <NUM>, returns from the kite <NUM>, extends across the boom <NUM> and back to the mast <NUM>).

The example UAV <NUM> includes a fuselage <NUM>, wings <NUM> each of which includes a distal capture portion <NUM>, and a propulsion system <NUM>. In this example, the distal capture portion <NUM> extends from at least one of the corresponding wings <NUM> generally along a direction of movement of the UAV <NUM>. However, any appropriate type of capture or recovery mechanism can, instead, be implemented on any other portion and/or component (e.g., the fuselage <NUM>) of the UAV <NUM>. Further any other appropriate type of propulsion of the UAV <NUM> can be implemented.

To recover and/or capture the UAV <NUM> as the UAV <NUM> moves along a flight path <NUM>, one of the distal capture portions <NUM> is brought into contact with the first portion <NUM> of the tether line <NUM> extending between the boom <NUM> and the base <NUM>. The UAV <NUM> contacting the tether line <NUM> causes the kite <NUM> to displace, thereby decelerating the UAV <NUM> in a highly effective and controlled manner. As a result, the UAV <NUM> is brought to a rest or stop with minimal force and/or stress and remains attached to the tether line <NUM>. In this example, the first portion <NUM> of the tether line <NUM> is suspended by the boom <NUM> (e.g., substantially vertically in the air, within <NUM> degrees from vertical) above the base <NUM> but is also operatively coupled to the kite <NUM> so that the kite <NUM> can facilitate controlled deceleration of the UAV <NUM>.

<FIG> is a detailed view of a portion of the example UAV recovery system <NUM> of <FIG>. As can be seen in the illustrated example of <FIG>, the boom <NUM> is depicted extending from the mast <NUM>. As mentioned above in connection with <FIG>, the tether line <NUM> is attached to the kite <NUM> of <FIG>. In particular, the support line <NUM> of the kite <NUM> is coupled to the tether line <NUM> at a mount <NUM>, which can operate as a coupling point (e.g., a fixed point) between the tether line <NUM> and the support line <NUM>. The mount <NUM> can be positioned on the tether line <NUM> or the boom <NUM> (e.g., the second end <NUM> of the boom <NUM>). In other examples, the tether line <NUM> extends above the boom <NUM> to contact the kite <NUM>. In some such examples, the support line <NUM> is integral with the tether line <NUM>. In this example, a pulley (e.g., a one-way pulley, a braking pulley, etc.) <NUM> and guides <NUM> direct and/or guide the tether line <NUM> from the base <NUM> shown in <FIG> to the boom <NUM> and, in turn, the mast <NUM>. As a result, the guided movement of the tether line <NUM> enables kinetic energy from the UAV <NUM> to be effectively dissipated as the UAV <NUM> is being decelerated during recovery thereof.

In the illustrated example, to couple movement of the tether line <NUM> with displacement and/or movement of the kite <NUM> when the UAV <NUM> is brought into contact with the portion <NUM> of the tether line <NUM>, the support line <NUM> is coupled to the tether line <NUM> via the mount <NUM>, which operates as a fixed point of the tether line <NUM> in this example. The mount <NUM> moves and/or displaces along with the tether line <NUM> during deceleration of the UAV <NUM>, thereby causing the kite <NUM> to move (e.g., causing a sudden or jerking motion of the kite <NUM>). The example mount <NUM> can be implemented as or generally shaped as a loop or ring (e.g., a ring, an annular ring, a loop of the tether line <NUM>, etc.) to couple the support line <NUM> to the tether line <NUM>. As will be discussed in greater detail below in connection with <FIG>, the support line <NUM> can be attached to a loop or ring defined by the tether line <NUM>. In some examples, the mount <NUM> is defined as a tied knot of the tether line <NUM>. Additionally or alternatively, the pulley <NUM> and the guides <NUM> can be adjusted to vary deceleration of the UAV <NUM>.

In some examples, a spring <NUM> is implemented to dampen motion of the tether line <NUM> and/or the kite <NUM>. In some examples, a brake <NUM> is implemented to control movement of the tether line <NUM>, the pulley <NUM> and/or the kite <NUM>. For example, the brake <NUM> can be operatively coupled to the pulley <NUM> to vary rotational movement of the pulley <NUM> and, in turn, motion of the tether line <NUM> and the kite <NUM> can be accurately controlled. The brake <NUM> can be electronically-controlled, force-controlled (e.g., via a force-reaction device) or manually-controlled. In some examples, as generally indicated by a double arrow <NUM>, an angle of the boom <NUM> relative to the mast <NUM> can be adjusted to vary a degree to which the kite <NUM> decelerates the UAV <NUM> shown in <FIG>. Additionally or alternatively, a height at which the kite <NUM> is positioned is changed to vary the degree to which the kite <NUM> decelerates the UAV <NUM>. In some examples, as generally indicated by a double arrow <NUM>, the boom <NUM> is telescoping and its longitudinal length can be varied to change a degree to which the kite <NUM> decelerates the UAV <NUM>.

In some other examples, different kites are interchanged and/or selected based on a type or configuration of aircraft being recovered and/or environmental conditions (e.g., wind conditions, kite hovering height limitations, etc.). In other words, different kites can be coupled to the tether line <NUM> and/or the mount <NUM> based on different aircraft configuration types and/or environmental conditions. In some such examples, utilization of the aforementioned mount <NUM> facilitates interchangeability between the different kites by enabling relatively easy and quick installation of the kites.

<FIG> is a detailed view of an example loop <NUM> that can be implemented in examples disclosed herein. In particular, the example loop <NUM> can be implemented onto the tether line <NUM> and/or the mount <NUM>. The loop <NUM> of the illustrated example is positioned on or proximate the second end <NUM> of the boom <NUM> shown in <FIG>. In this particular example, the loop <NUM> is implemented as an alpine butterfly knot of the tether line <NUM>. However, any other appropriate knot (e.g., a figure <NUM> knot, a noose knot, a square knot, an overhand knot, a slip knot, etc.) or other looped/loop-like structure can be implemented instead.

<FIG> is a flowchart representative of an example method <NUM> to implement the example UAV recovery system <NUM> of <FIG>. In this example, an aircraft (e.g., the UAV <NUM>) is going to be recovered by the tether line <NUM> and the kite <NUM> is to decelerate the UAV <NUM> during recovery of the UAV <NUM>.

At block <NUM>, the kite <NUM> is launched and/or deployed. In this example, the kite <NUM> is coupled to the tether line <NUM> (e.g., at the mount <NUM>), thereby coupling motion between the kite <NUM> and the tether line <NUM>. In other words, movement of at least a portion of the tether line <NUM> causes movement of the kite <NUM>. In some examples, a height to which the kite <NUM> is launched is varied based on a desired degree of deceleration of the aircraft (e.g., a greater height corresponds to a greater degree of deceleration of the aircraft).

At block <NUM>, the tether line <NUM> is suspended by the kite <NUM> operatively coupled thereto. In the illustrated example, the portion <NUM> of the tether line <NUM> is suspended (e.g., held in tension) between the boom <NUM> and the base <NUM> and/or the ground for impact with the aircraft. In some examples, the tether line <NUM> is routed through a fixed point of at least one of the boom <NUM> and/or the tether line <NUM>.

At block <NUM>, in some examples, a height at which the kite <NUM> is deployed is changed and/or adjusted. In some such examples, the height may be adjusted on flight data of the aircraft and/or changing conditions (e.g., changing wind conditions, changing weather conditions, etc.).

At block <NUM>, in some examples, the boom <NUM> is adjusted. In some examples, an angle of the boom <NUM> (e.g., an angle of the boom <NUM> from the ground) is adjusted to vary a degree of deceleration of the aircraft. Additionally or alternatively, a longitudinal length of the boom <NUM> is adjusted (e.g., the boom <NUM> is telescoping).

At block <NUM>, the aircraft is brought into contact with the tether line <NUM>. In this example, the aircraft is flown along a flight path that results in a distal portion of a wing of the aircraft contacting the tether line <NUM>. In turn, the aircraft is decelerated to a stop as the tether line <NUM> moves the kite <NUM>. In other words, movement of kite <NUM> dissipates kinetic energy of the aircraft. In some examples, the aircraft is coupled (e.g., releasably coupled) to the tether line <NUM> in response to impacting the tether line <NUM> (e.g., the aircraft hangs from the tether line <NUM> after impacting the tether line <NUM>).

At block <NUM>, in some examples, the brake <NUM> is operated. In particular, the brake <NUM> can be operated to slow down and/or prevent movement of the tether line <NUM> as the aircraft is being recovered (i.e., after the aircraft has been brought to a rest via the tether line <NUM> and the kite <NUM>). Additionally or alternatively, the brake <NUM> is implemented to prevent, reduce and/or dampen movement of the tether line <NUM> as the aircraft is being decelerated (e.g., to prevent excess movement of the tether line <NUM> prior to the aircraft being recovered). The example brake <NUM> can be implemented to reduce and/or slow down movement of the pulley <NUM>. According to some examples, the spring <NUM> is implemented (e.g., in-line with or operatively coupled to the tether line <NUM>, at the mount <NUM>, between the support line <NUM> and the tether line <NUM>, etc.) to dampen motion of the tether line <NUM> and/or the kite <NUM> during recovery of the aircraft.

At block <NUM>, the aircraft is drawn in toward the base <NUM>. In some examples, the tether line <NUM> is displaced and/moved (e.g., moved linearly, moved by a winch) so that the aircraft can be removed from the tether line <NUM>. In some examples, an operator removes the aircraft from the tether line <NUM> as the aircraft is suspended by the tether line <NUM>.

At block <NUM>, in some examples, the kite <NUM> is replaced with another kite, which can correspond to a different type or configuration of aircraft being recovered, etc. In some such examples, the replacement kite is coupled to the tether line <NUM> at the mount <NUM>.

At block <NUM>, it is determined whether to repeat the process. If the process is to be repeated (block <NUM>), control of the process returns to block <NUM>. Otherwise, the process ends. This determination may be based on whether additional aircraft are to be recovered.

From the foregoing, it will be appreciated that example methods, apparatus and articles of manufacture have been disclosed that enable highly controlled and cost-effective recovery of aircraft. Examples disclosed herein can also reduce forces and/or stresses imparted to aircraft during recovery thereof. Examples disclosed herein also enable aircraft that have a relatively light weight and low cost because they do not necessitate significant structural reinforcements and components for landing, etc..

Although certain example methods, apparatus and articles of manufacture have been disclosed herein, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all methods, apparatus and articles of manufacture falling within the scope of the claims of this patent.

Claim 1:
An apparatus (<NUM>) to recover an aircraft (<NUM>), the apparatus (<NUM>) comprising:
a base (<NUM>);
a mast (<NUM>) extending from the base (<NUM>);
a boom (<NUM>) extending from the mast (<NUM>) at a first end (<NUM>) of the boom (<NUM>) to a second end (<NUM>) of the boom opposite the first end (<NUM>);
a tether line (<NUM>) extending between the mast (<NUM>) and the base (<NUM>), said tether line being guided by the boom (<NUM>), a portion (<NUM>) of the tether line (<NUM>) extending between the second end (<NUM>) of the boom (<NUM>) and the base (<NUM>);
a kite (<NUM>) coupled to the tether line (<NUM>) via a support line (<NUM>); and
a mount (<NUM>) configured to operatively couple the support line (<NUM>) to the tether line (<NUM>), the kite (<NUM>) being configured to support the tether line (<NUM>) as the aircraft (<NUM>) contacts the portion (<NUM>) of the tether line (<NUM>) extending between the second end (<NUM>) of the boom (<NUM>) and the base (<NUM>) for recovery of the aircraft (<NUM>),
wherein the mount (<NUM>) is configured to move and/or displace along with the tether line (<NUM>) during deceleration of the aircraft (<NUM>), thereby causing the kite (<NUM>) to move.