UNMANNED AIR VEHICLE RECOVERY SYSTEM

Embodiments of the present disclosure relate generally to safe arrestment and recovery of an airborne unmanned air vehicle (UAV). Specific embodiments provide a recovery net that can recover a UAV approaching a cargo plane, the UAV either traveling in the same direction as the cargo plane or in an opposite direction of the cargo plane. The systems described herein may also be used as an air-only based system.

FIELD OF THE DISCLOSURE

Embodiments of the present disclosure relate generally to safe arrestment and recovery of an airborne unmanned air vehicle (UAV). Specific embodiments provide a recovery net that can recover a UAV that is either approaching an air cargo plane from the same of an opposite direction.

BACKGROUND

Many recovery systems for UAVs that are currently available use a net system that the UAV engages while still in flight. In some examples, the net system includes a vertical flat plane configuration, as shown inFIG. 1. There are also systems that use a boom-mounted vertical cable that engages a clip mechanism on wingtips of the UAV. In use, the UAV engages the cable along the edge of the wing, and the cable slides toward the wingtip in order to engage the clip mechanism. An example of this system is a shown inFIG. 2.

Typically, air vehicles land into the wind in order to take advantage of the lift provided. This added lift allows a decrease in the speed required to safely land. Many existing UAV recovery net systems must be positioned such that they are perpendicular to the wind direction. This positioning can allow the UAV to land into the net, in the direction of the wind. However, depending upon the size and configuration of the recovery net system, positioning the net to be perpendicular to the wind may be difficult and time-consuming in some instances. For example, in the case where the recovery net is mounted on a ship, the ship must be turned to position the net appropriately, which is not optimal.

Land-based UAV recovery net systems typically require a significant amount of secure, open land for deployment and operation. This is not always an option in uncontrolled, unfriendly, or densely populated urban areas. Accordingly, improved UAV recovery systems are desirable.

BRIEF SUMMARY

Embodiments of the invention described herein thus provide systems and methods for a UAV recovery system that allows a UAV to be safely captured, regardless of whether it is traveling in the same or a different direction than the recovery cargo plane, and regardless of the wind direction.

Embodiments also provide a UAV recovery system that allows for UAV capture at a wide range of altitudes and/or terrains. In a specific example, the UAV recovery system is provided as a recovery net for engagement of a UAV approaching from varying directions. In a more specific example, the recovery net may be a cone-shaped net that trails behind a cargo plane. The recovery net may be provided with a structural ring that ensures deployment of the recovery net in a reliable manner for UAV capture. The recovery net may be provided with one or more parafoil panels that assist with stabilizing the recovery net. Other options are described in more detail below.

DETAILED DESCRIPTION

Embodiments of the present invention provide a UAV recovery system10that can capture one or more UAVs approaching the system10from any direction, regardless of the wind direction. In the examples shown, the system10may include a 360 degree capture engagement cage12. The 360 degree capture engagement cage12may be formed as a circular component and functions as a recovery net. It may have an upper support14and a lower support16between which may extend a net portion18. In one example, the upper and lower supports14,16are formed with a circular nature. This would provide a generally cylindrical engagement cage12. In other examples, the upper and lower supports14,16may be any other shapes, such as square-shaped, hexagonal, octagonal, or any other multi-sided geometry. The shapes of the upper and lower supports14,16will generally dictate that shape that the net portion18takes. The general goal is to provide a multi-faceted or cylindrical capture portion that can capture a UAV traveling and approaching the cage12from any direction.

As will be described further below, the net portion18is designed to receive and recover one or more incoming UAVs20. The net18may be a webbed net structure that cooperates with an anchoring mechanism60or other interface on the UAV. The anchoring mechanism or other interface may penetrate, adhere to, or otherwise temporarily secure the UAV with respect to the net18. The engagement cage12may then be lowered in order to recover the captured UAV.

The net portion18may thus provide a 360° engagement opportunity for capturing a UAV20. This allows a UAV to be safely captured from any direction, regardless of the wind direction. The generally cylindrical or circular nature of the engagement cage12means that it can be deployed the same way, regardless of the particular wind direction or weather condition. As shown, the engagement cage12may have a central axis A. A UAV20may approach the cage from any angle with respect to the central axis A in order to be captured. Various additional and optional features of the 360 degree capture engagement cage12will be described further below.

The UAV recovery system may be positioned along one or more tethers22that secure the system to an appropriate structure. In one example of use, the UAV recovery system10may be suspended from an autonomous airship25, as shown inFIGS. 3 and 4. For this example, a lower securement feature is not provided. In other examples, the UAV recovery system10may be tethered from above and below. For example, the system10may be tethered from an aerostat24traveling above the system10and also tethered to the ground, a ground vehicle, or a ship deck, or other structure below the system10. One example of this feature is a shown inFIG. 5.

These various tethering options allow the UAV recovery system10to be used at a wide range of altitudes. For example, if used with an autonomous airship25ofFIG. 3, UAVs20may be recovered in a remote location and then returned to an operation base. No ground structure is necessary. This example also requires a relatively small footprint for UAV recovery operations. Additionally, this airborne only embodiment can provide an advantage where variations in terrain, urban structures, or other obstacles make it impractical or impossible to deploy traditional existing land or ship-based recovery systems. They may also be useful for operations in uncontrolled, unfriendly, or densely populated urban areas.

As shown inFIG. 3, the upper end26of the cage12may be secured to an airship tether22. There may be one or more cords or lines28that secure the engagement cage12to the tether22. The airship25may serve as the primary energy absorber, because it can move freely in the direction of the arrestment in order to allow the shock imparted to the net18/cage12to be absorbed over a distance. It may be desirable to provide an optional lower counter weight50in order to stabilize the engagement cage12upon contact with the UAV20. One example of a counter weight50may be gas bottles or any other type of weights.

Using gas bottles as it counterweights50may be particularly advantageous in the deployment options shown byFIG. 6. In this option, the UAV recovery system10may be deployed to a target area in mid-air, e.g., via a cargo plane70. The system10may be tethered to an airship25and packaged as a unit72. The packaged recovery system unit72may be associated with an optional parachute or parasail74. The unit72may be loaded onto a cargo plane70and ejected at an appropriate altitude. Upon ejection, the airship25may rapidly inflate via air from the gas bottles50(which also function as counterweights). The inflation may take place via a breakaway inflation to84, which would allow the gas bottles50to deliver inflation gas to the airship25, and then release to hang below the engagement cage12, as shown. The airship25may then navigate (or be remotely/externally navigated) to the target area. Once the airship25is inflated, the parachute/parasail74may detach. The cage12may fully deploy and remain in the target area until the UAVs are recovered. The airship25could then navigate to a secure recovery area. It is also possible for the system10to be launched from the ground.

In another embodiment, there may be provided a ground vehicle or ship-mounted aerostat system52. One example is illustrated byFIG. 5. In this example, the system52includes an aerostat24tethered to a360degree capture engagement cage12, which is in turn tethered to a vehicle54below. The engagement cage12may be moved up and down the tether22via a pulley system. It is also possible to provide an upper tether that is separate from a lower tether. In this example, the two tethers provided may each have an extended payout line which could pull the engagement cage12up toward the aerostat24or lower the engagement cage down toward the lower securement location.

In one example, the vehicle54may be an operations vehicle/trailer. In another example, the vehicle54may be a ship, aircraft carrier, or water-based vehicle or stationary platform. In another example, a lower end of the tether22may be secured to a stationary point on the ground, such as a hook or other structure. These ground-supported configurations may provide control during capture of the UAV in a persistent service area. The system52can be deployed with a relatively small footprint for a ground or sea-based launch and recovery operation. The system52could be used for both short and long-term operations. In urban areas, the system could be raised above buildings or other obstructions for recovery operations.

The altitude of the aerostat24and the length of tether(s)22may be altered as needed. This provides a system that can capture UAVs at a large range of altitudes. Additionally, the size of the aerostat could be altered based on the energy (e.g., weight and speed) of the UAV to be captured. For example, a larger “balloon” may be used to capture a heavier UAV.

A raise/lower mechanism may be provided that functions to lower and raise the cage12along the tether22. For example, this may be a pulley system, a manual system, an electronic system, or any combination thereof. This may allow the UAV recovery system10to be deployed, as well as for UAVs20to be unloaded from the cage12upon recovery, without lowering the aerostat24.

Depending on the size of the net18or the cage12and the size of the UAV to be recovered, it may be possible to capture multiple UAVs with a single UAV recovery system10. For example, multiple captures may be made prior to lowering the system to remove the UAV. In this example, the autonomous airship25or aerostat24may be positioned in a target area and remain in place until all UAVs have been recovered. The airship may then return to its base of operations for unloading.

In one option, it is possible to provide more than one engagement cage12along a tether22, in order to allow capture of multiple incoming UAVs20. One example of this is shown inFIG. 7.

As is shown inFIGS. 8A and 8B, one embodiment may provide a360degree capture engagement cage12that is supported by a support structure34. The support structure34may include an angled arm36that has an upper portion38secured to an upper net portion28. There may also be provided a vertical portion42and a lower portion44secured to a lower net portion46. It is also possible for the upper end of the360degree capture engagement cage12to be attached to an alternate support structure, such as a crane, boom, frame or stanchions. In any of these options, the structure could be attached to a rotating mechanism (at either an upper or lower portion of the cage), such that the support structure could be repositioned out of the path of an inbound UAV. This embodiment may be provided as a fixed recovery system10, designed to have a fixed base that is positioned on and fixed to the ground, a ground-based vehicle, such as an operations truck or trailer, on an aircraft carrier or ship, or any other structure.

A mechanism to rotate the entire cage12may be used for orientation in the event that there is a need for multiple captures from the same direction.FIG. 8Aillustrates one embodiment of a rotating mechanism30. In this example, there is provided a rotating base30. It should be understood, however, that a rotating mechanism30may also be provided at an upper portion of the cage12. The rotating mechanism30can help rotate the engagement cage12such that an empty area of the net portion18is accessible for catching an incoming UAV20. This is particularly useful if multiple UAVs are to be captured prior to lowering of the cage12.

This recovery sequence may use an off-center capture approach. In this example, the UAV may engage the net or cage with an anchoring mechanism60at the wing tip. The cylindrical net18may be suspended within or otherwise with respect to the support structure34. A rotating mechanism30and rotary energy absorber48may be provided. The rotating support structure base may allow the structure34to be repositioned out of the path of an inbound UAV.

As shown, it is also possible for the system10to include one or more optional energy absorbers48. In one example, the energy absorber48may be a hydraulic brake, such as a Water Twister™, manufactured and sold by Zodiac Aerospace. A Water Twister™ is an energy absorbing water brake that converts kinetic energy to heat through fluid turbulence. This brake may include fluid with a rotor having vanes attached to an axle. The axle may be attached to the net structure. Movement of the vanes in the fluid creates turbulence/cavitation to absorb energy of the UAV. Other energy absorbers are possible and considered within the scope of this disclosure. For example, friction brakes are possible and considered within the scope of this disclosure. As another example, in one embodiment, a central portion66of the 360 degree capture engagement cage12may be provided with a cushioning or compressible material which can help facilitate shock absorption and aid in the absorption of the UAV impact.

As shown in the figures, the net portion18is generally shown as having a series of openings58therethrough. The UAV20may have an anchoring mechanism60attached thereon. In use, the anchoring mechanism60engages one or more openings58of the net18of the cage12and securely fastens the UAV20thereto. Non-limiting examples of potential anchoring mechanisms60are shown inFIGS. 9 and 10. The anchoring mechanism60may be located on any portion of the UAV20. For example, it may be positioned at the nose tip of the UAV, a wing tip of the UAV, or elsewhere.

In the example shown inFIG. 9, the anchoring mechanism60may be a spring loaded-toggle62that can penetrate the net18and then open to effectively trap the UAV20with respect to the net18. In another example shown inFIG. 10, the anchoring mechanism60may be a net-penetrating barb64. The barb64may penetrate the net and trap the UAV with respect to the net. The barb64may then be detachable, collapsible, retractable, in order to release the UAV from the net. For example, the barb64may fully detach. As another example, the barb64may collapse upon itself. As another example, the barb64may retract into the UAV fuselage. In another example, the anchoring mechanism may be a clip that secures the UAV to the net. Other anchoring mechanisms are also possible and considered within the scope of this disclosure. It should be understood, however, that other capture systems are possible, and may include the net being designed to envelop or capture at least a substantial portion of the UAV.

Alternatively, it is possible for other capture systems to halt the UAV with respect to the net. For example, the cage may be designed such that it envelops or bags the UAV after capture. For example, the net may envelop the UAV at the point of impact and stop the UAV from forward momentum.

In order to retrieve the UAV recovery system10, a cargo plane or helicopter or other aerial vehicle70may be equipped with a mid-air retrieval hook and winch system76. One example of a recovery sequence as shown inFIG. 11. A hook element78may be extended from the aerial vehicle70and engage with a deflation valve80of the airship25. This may cause the airship to deflate. A winch system82, typically mounted on the aerial vehicle70, may then pull the deflated airship25and the cage12on-board.

The net portion18may be formed from any appropriate material. It is generally desirable for the material to have a flexibility that is sufficient to envelope the UAV upon contact, but to also have a strength that is sufficient to withstand and halt the incoming force of a UAV. Examples of potential net materials include but are not limited to nylon web, polypropylene cords, polyester, or synthetic polymers. The net may be woven or non-woven. Other potential net designs may include metal cables that can capture a wing tip latch or other structure on the UAV. Further potential net designs may include a net portion made of Geckskin™ or other synthetic adhesive surface that can hold and detach objects of great weight. It is believed that a Geckskin or other synthetic adhesive net may operate to capture UAVs having anchoring mechanisms and/or UAVs without anchoring mechanisms.

In any of the embodiments described herein, the net portion may be fabricated from flexible or non-flexible members or a combination thereof. In one example, the materials of the360degree capture engagement cage12are designed to collapse inwardly upon UAV20impact in order to help absorb the initial energy. The net material moves upon impact with the UAV and is flexible enough to envelop the UAV, at least momentarily. This net movement may fully engage the UAV until its removal from the net and/or this net movement may simply allow enclosure of the UAV until the anchoring mechanism60(if provided) can be deployed.

Although the system has been described as having a 360 degree capture engagement cage, it should be understood that a shape other than cylindrical may be used to facilitate 360° engagements. For example, the engagement cage may have any other appropriate shape. The general intent is to provide a 360° capture area that provides more aerial coverage than a vertical net or a single cable.

The cage12and/or the UAV20may be equipped with electronic or optical guidance equipment to ensure accurate UAV to net engagement.

It is also possible to use the airship25or aerostat24to launch UAVs, as well as recover UAVs. One example of this is shown inFIG. 12.

In one example, there is provided an unmanned air vehicle (UAV) recovery system, comprising: a 360 degree engagement cage comprising an upper support, a lower support, and a circumferential net portion extending therebetween, an airship or aerostat configured to support the cylindrical engagement net via a tether. The upper support may be a generally cylindrical upper support, and the lower support may be a generally cylindrical lower support. The circumferential net portion may be a generally cylindrical net portion. The net portion of the 360 degree engagement cage may have one or more openings configured to capture a UAV. The UAV to be captured may have an anchoring mechanism for cooperation with the net portion. The anchoring mechanism can temporarily fix the UAV to the net.

In other examples, there is provided an unmanned air vehicle (UAV) recovery system for aerial deployment, comprising: a packaged unit comprising an autonomous airship tethered to a 360 degree engagement cage with one or more inflation bottles, and a parachute secured to the packaged unit. The packaged unit may be configured for aerial deployment from an aerial vehicle. Upon aerial deployment, the autonomous airship inflates via delivery of inflation gas from the one or more inflation bottles and the 360degree engagement cage deploys, with the one or more inflation bottles functioning as a counterweight below the engagement cage.

FIGS. 13 and 14illustrate alternate embodiments of a UAV recovery system100. This system100can be deployed from a cargo plane102using the above-described winch system82. The winch system82can be mounted on the cargo plane102. Extending from the winch82is a tether104. The tether104may be a telescoping boom. The tether104may be a flexible tether. The tether104may be any other appropriate connection between the winch and the recovery net106. The recovery net106is towed behind the cargo plane102.

The recovery net106, which may also be referred to as a recovery drogue, may be formed from any of the above-described materials and methods. However, rather than being a360degree capture net, the recovery net106of this embodiment is provided as a cone-shaped net. The cone shape may provide beneficial aerodynamic conditions. In order to maintain the structural cone shape while deployed, the net106may have a structural ring108at its outer opening perimeter. The structural ring108may be embedded within the net material110in any appropriate manner. For example, it may be stitched within the net materials. It may be integrally formed as a reinforced area of net material. It may be clipped, secured, extend from, or otherwise be associated with the net material110in any way that causes the net material110to create a circular shape upon deployment. A useful analogy to consider may be a hoop associated with or connected to open edges of a cast net. The recovery net106may be collapsible, such that the structural ring108can be broken down into individual elements and/or telescope with respect to itself.

The net material110may be formed as having a cone-shaped cross-section, as illustrated. It should be designed to have a size that allows the material to envelope the entire UAV. The cone shaped cross-section may be formed with tapering sides112that meet at a net end114. The net end114may be secured with respect to the tether104. Because, in a direct/head-on catch, the net end114may be the portion intended to catch and stop the UAV, it is possible for net end114to have one or more reinforcing elements positioned thereon.

In order to assist with deployment and capture, the recovery net106may be provided with one or more counterweights that keep the net open and stable in use. The UAV may feature one or more of the anchoring mechanisms60described above for securement with respect to one or more openings52of the recovery net106.

FIG. 14illustrates a recovery system120that uses a plurality of recovery nets106. Although three recovery nets106are shown, it should be understood that more or fewer nets may be used. This system may be used for multi-UAV recovery. Rather than being attached directly from the net and to the tether, the multi-UAV recovery system120may feature and intermediate structure122. As is shown, the intermediate structure may include an array structure124associated with the tether104. The array structure124may be a collapsible array structure. The array structure124may be shaped as a triangular support, with upper and lower support126,128. There may also be provided internal support130. These supports may form a connection face132from which secondary tethers134a,134b,and134cmay extend and connect to net end114. The recovery nets106of this embodiment may be similar to those described above.

In use for both of the embodiments illustrated byFIGS. 13 and 14, the system100is useful for recovering a UAV traveling in the same direction as the cargo plane, illustrated by the arrows inFIGS. 13 and 14. The UAV approaches the recovery net106and is engaged by the net. The engagement may occur by any of the methods described herein with respect to the 360 degree engagement cage. Once engaged, the UAV system shuts down power. The tether104may be used to pull the recovery net106(with the captured UAV) on-board the cargo plane using a winch82or other mechanical retrieval system.

FIG. 15shows a side perspective of an air-based recovery system140that can capture a UAV coming from an opposite direction as the cargo plane. In this example, the recovery net142may be designed as a reverse cone shape. As shown, the opening144of the net may be supported by a plurality of members146. The members146may be parafoil panels. The parafoil panels may provide stability to the net and may function similarly to kite wings. The members146may collectively be secured to and extend from a tether104. As described above, the tether104may be a telescoping boom, a flexible tether, or any other appropriate extension member. It is possible for the recovery net142to also have a structural ring as described above to support and maintain the desired shape of opening144. In order for the recovery net142to maintain it open and stable position, a counterweight148may be provided along the lower portion of the net.

FIG. 16shows an alternate embodiment of a flat recovery net160. In this example, the recovery net160is trailed behind the cargo plane in a message banner style. The recovery net160may be weighted along one side of162in order to ensure an appropriate orientation of the net160upon deployment. The recovery net160travels in a generally perpendicular plane as compared to the path of the cargo plane. As in the above-discussed embodiments, there may be provided a tether and a winch system for deploying and recovering the net in use.

Although not shown, it is also possible for the 360° recovery net106described above to be similarly trailed behind a cargo plane. It is also possible for the net to be a spherical catch net/cage. In this example, a lower tether would not be provided. This option may also employ counter weights or airfoils or both that may be attached to the net. These options could be employed to cause the cage to be oriented vertically.

There may also be provided a method for recovering an unmanned air vehicle (UAV) using the recovery system, comprising: deploying the recovery system from an autonomous airship. There may further be provided a method for recovering an unmanned air vehicle (UAV) using any of the recovery systems described, by deploying the recovery system from a land or water based structure and tethering the engagement cage to an aerostat. There may further be provided a method for recovering a UAV comprising assembly or causing assembly of the structural ring and deploying the recovery system from a cargo plane.

Changes and modifications, additions and deletions may be made to the structures and methods recited above and shown in the drawings without departing from the scope or spirit of the disclosure or the following claims.