A fixed-wing UAV shipborne inflatable recovery platform, deployment and recovery method

Abstract

The present invention relates to a ship-borne inflatable recovery platform for fixed-wing unmanned aerial vehicles (UAVs), belonging to the technical field of UAVs. Airbags are used as the platform's main supporting components, and steel cables are used as tension components to achieve functions similar to those of a beam structure. During the contraction and expansion process, the internal pressure of each sub-airbag, the tension of the upper and lower steel cables, and the tension of each sub-airbag are controlled by a rope control system, an inflation and deflation system, and a remote control valve, so that each sub-airbag can be contracted and expanded in sequence, thereby realizing the retraction and expansion function of the platform. The platform does not occupy deck space, is lightweight, and is retractable. When not in operation, it has little impact on the outer contour of the ship.

Description

Technical Field

[0001] The present invention relates to the technical field of unmanned aerial vehicles (UAVs), and in particular to a ship-borne inflatable recovery platform for fixed-wing UAVs, and a deployment and recovery method thereof. Background Art

[0002] Drones generally have stronger fuselages than manned aircraft and are not subject to the physical limitations of pilots, allowing for more extreme shipboard recovery methods. Drone shipboard recovery requires safety, reliability, maneuverability, high reusability, minimal damage to the aircraft and onboard equipment, ease of operation, and convenient maintenance to meet economical requirements. Traditional methods for recovering small drones from ships primarily include net-striking shipboard recovery, skyhook recovery, and parachute recovery.

[0003] The net-crashing recovery method involves deploying a recovery net at the stern of a ship, allowing the drone to fly directly into the net. After successful capture, the drone is lowered and manually removed from the net. To date, typical structures for drone net-crashing recovery systems at home and abroad include four schemes: a single net with three poles, a double net with two poles, a single net with a single pole, and a single net with two poles. The first two require energy-absorbing buffer devices, while the single net with a single pole requires a rotary drive device and a damper. The single net with two poles primarily relies on the elastic deformation of the net and bracket to absorb and buffer the drone's energy, eliminating the need for additional damping devices. The net-crashing recovery method requires minimal deck space and simple equipment. The recovered drone does not require a landing device, and the landing trajectory tracking accuracy requirements are low, requiring only the lowest possible net-crashing speed.

[0004] Skyhook recovery technology is developed based on net-based recovery technology. A skyhook recovery system typically consists of a capture device (a small hook on the drone's wingtip, a recovery frame, and a recovery rope), an energy-absorbing buffer, and a guide. The guide guides the drone to the capture device. When the drone's wing strikes the recovery rope, the rope slides along the wing to the wingtip, where the small hook on the wingtip hooks and locks the rope. The engine then shuts down, and the drone then spins around the rope to decelerate. When the swing amplitude decreases to a certain level, it is manually removed and recovered. This recovery mechanism is relatively simple and suitable for use on smaller ships. It can also meet the takeoff and landing requirements of larger drones.

[0005] Parachute recovery involves deploying a parachute to a suitable altitude and reach a recovery area, achieving a speed buffer. This method is widely used for low-speed drones. The drone is equipped with a recovery parachute, which decelerates the drone and allows it to touch the ground at a lower speed, allowing recovery. This method offers advantages such as light weight, minimal space requirements, a small packaged volume, relatively low cost, stable performance, simple processing, and low dynamic loads from parachute deployment. Summary of the Invention

[0006] Technical problems to be solved

[0007] The net-impact landing recovery method has the following disadvantages: 1. When hitting the net, the lateral speed and sideslip angle should be reduced as much as possible, otherwise the probability of damage to the drone will increase; 2. For drones using propellers, it is easy for the blades to break or cut through the recovery net during recovery, increasing the risk of damage to the drone and the cost of repair, thereby affecting the preparation time and work efficiency of the recovery device; 3. This recovery method requires a lot of manual operation and is difficult to mechanize.

[0008] How to ensure that the drone can decelerate at the expected attitude during the Skyhook recovery is a major difficulty in the recovery operation.

[0009] The parachute recovery method has the disadvantage that the parachute is easily affected by the wind, and the error cannot be corrected after the parachute is opened, which makes it easy for the drone to collide with the deck building.

[0010] From the first landing of an aircraft on a ship to the development of parachute / parafoil recovery and net recovery, the above methods are only applicable to the recovery of small drones. Currently, there is no better method for recovering medium and large drones from ships at sea.

[0011] To overcome the aforementioned shortcomings of the prior art, the present invention provides a ship-borne inflatable recovery platform for fixed-wing UAVs. Airbags provide support for the platform, while steel cables provide tension above the airbags. The platform takes up no deck space, is lightweight, and is retractable, minimally impacting the ship's exterior when not in operation.

[0012] Technical Solution

[0013] A fixed-wing UAV shipborne inflatable recovery platform, characterized in that it includes a fixed end structure, an airbag cable support structure, a flexible steel cable, an airbag, a flexible braided belt, a cover plate and a remote control valve; the fixed end structure is fixedly connected to the airbag reinforcement frame on the stern of the ship and the first sub-airbag; the airbag cable support structure is connected to the airbag and the flexible steel cable; the airbag is composed of twelve sub-airbags connected end to end in the axial direction, and a remote control valve is installed at each junction, and an inflation and deflation system is provided at the first sub-airbag and connected to the fixed end structure; the flexible braided belt is wrapped around the steel cable at the upper end of the platform.

[0014] A further technical solution of the present invention is as follows: the fixed end structure is a hinge structure, and when the platform is in a working state, the fixed end structure is in a locked state; when the platform is recovered or begins to unfold, it is in a rotatable state, so that the platform can be folded and placed vertically at the stern of the ship when it is in a non-working state.

[0015] Further technical solution of the present invention: the airbag steel cable support structure includes an airbag reinforcement frame and a support rib, wherein the shape of the airbag reinforcement frame is the same as the cross-sectional shape of the airbag, is attached to the surface of the airbag and is fixedly connected to the airbag; each support rib is a rectangular metal plate, and a through hole is opened at the upper position to allow the steel cables on both sides of the upper end of the support rib to pass through, and is fixedly connected to the airbag reinforcement frame, thereby transferring the load on the steel cables at the upper end of the support rib to the airbag, and maintaining the spacing between the steel cables at the upper end of the support rib unchanged.

[0016] A further technical solution of the present invention is that a limiting hole is provided at the bottom end of the airbag reinforcement frame to prevent the steel cable at the lower end of the airbag reinforcement frame from slipping when the platform is running.

[0017] A further technical solution of the present invention: the flexible steel cable is composed of five steel cables at the upper end of the support rib and two steel cables at the lower end of the airbag reinforcement frame. The middle three of the five steel cables at the upper end of the support rib are fixedly connected to each support rib, and the steel cables on both sides pass through the through holes on each support rib; at the first sub-airbag, the steel cables on both sides of the upper end of the support rib and the steel cables at the lower end of the airbag reinforcement frame are connected to the rope control system; at the terminal airbag, the steel cables at the upper end of the support rib and the steel cables at the lower end of the airbag reinforcement frame are both fixed on the terminal rib, forming a form in which the flexible steel cables are wrapped in a circumferential direction along the axis of the airbag.

[0018] A further technical solution of the present invention is as follows: the cross-sectional shape of each sub-airbag is two intersecting outer contour parts passing through the center of each circle, and the junction of each sub-airbag is located at the airbag reinforcement frame.

[0019] A further technical solution of the present invention is that the sub-airbag material is a nylon-rubber composite material.

[0020] A method for deploying a shipborne inflatable recovery platform for a fixed-wing unmanned aerial vehicle (UAV), characterized by: releasing a locking mechanism of a fixed-end structure, changing the platform from being attached perpendicularly to the rear deck to being parallel to the rear deck; adjusting the fixed-end structure to lock it, and keeping all remote control valves closed; then, using a rope control system to pull the steel cables on both sides of the upper end of the support rib and the steel cables at the lower end of the airbag reinforcement frame; and simultaneously using an inflation and deflation system to inflate the root airbag, thereby gradually deploying the first airbag at the root; after an appropriate pressure is established in the first sub-airbag, the sub-airbag is in a state of equilibrium due to the axial force generated by the internal pressure and the tension generated by the steel cables on both sides of the upper end of the support rib and the steel cables at the lower end of the airbag reinforcement frame; then, opening a remote control valve between the first and second sub-airbags to inflate the second airbag, thereby deploying the first two sub-airbags; repeating the above steps to fully deploy all 12 sub-airbags in sequence; and when each sub-airbag has deployed to a fixed position, the rope control system secures the four steel cables, and the inflation and deflation system maintains a constant internal pressure in the airbag.

[0021] A recovery method for a fixed-wing UAV shipborne inflatable recovery platform is characterized in that: first, each remote control valve is closed to keep the internal pressure of each airbag independent and unchanged; then, the steel cables on both sides of the upper end of the supporting rib and the steel cable at the lower end of the airbag reinforcement frame are pulled through the rope control system, which will inevitably cause the internal pressure of the first sub-airbag to increase; then the inflation and deflation system autonomously deflates the first sub-airbag, thereby realizing the recovery of the first sub-airbag; after the first sub-airbag is recovered, the remote control valve between the first sub-airbag and the second sub-airbag is opened, and the steel cable is pulled and deflated on the second sub-airbag to realize the recovery of the second sub-airbag; the above operations are repeated to recover 12 sub-airbags in sequence; finally, the recovered 12 sub-airbags are rotated to hang on the rear deck by rotating the fixed end structure.

[0022] Beneficial effects

[0023] The present invention provides a fixed-wing UAV shipborne inflatable recovery platform, which uses airbags as the main supporting components of the platform and steel cables as tension components to achieve functions similar to those of a beam structure. During the contraction and expansion process, the internal pressure of each sub-airbag, the tension of the steel cables on both sides of the upper end and the lower end are jointly controlled by a rope control system, an inflation and deflation system, and a remote control valve, so that each sub-airbag can be contracted and expanded in sequence, thereby realizing the retraction and expansion function of the platform.

[0024] The fixed-wing UAV shipborne inflatable recovery platform takes up no deck space when operating or non-operating. In this non-operating state, it hangs from the rear deck, barely altering the ship's profile and having no impact on the ship's aerodynamic and electromagnetic characteristics. When in operation, the platform is inflated, allowing it to deploy flatly from the rear deck, making the runway surface identical to a traditional runway. Therefore, there's no need to modify the shipborne UAV to accommodate the platform. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like parts throughout the drawings.

[0026] Figure 1 This is a schematic diagram of the working state of a fixed-wing UAV ship-borne inflatable recovery platform;

[0027] Figure 2 This is an oblique view of the present invention after inflation and expansion;

[0028] Figure 3 This is a front view of the present invention after inflation and expansion;

[0029] Figure 4 It is a front view of the recycling process of the present invention;

[0030] Figure 5 This is a front view of the present invention after complete recovery;

[0031] Figure 6 This is a side view of the first sub-airbag;

[0032] Figure 7 It is a cross-sectional view of the middle plane of the airbag reinforcement frame;

[0033] Figure 8 This is a partial view of the platform root. DETAILED DESCRIPTION

[0034] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only intended to illustrate the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0035] Reference Figure 6-Figure 8 A fixed-wing UAV shipborne inflatable recovery platform comprises a fixed-end structure 1, an airbag cable support structure, a flexible steel cable, an airbag 2, a flexible braided belt 3, and a remote control valve 13. The fixed-end structure is fixedly connected to the airbag reinforcement frame at the stern of the ship and on the first sub-airbag; the airbag cable support structure is connected to the airbag and the flexible steel cable; the airbag is composed of twelve sub-airbags connected end to end, with remote control valves installed at each junction. An inflation and deflation system is installed on the first sub-airbag and connected to the fixed-end structure; the flexible braided belt is wrapped around the steel cable at the upper end of the platform.

[0036] One end of the fixed end structure 1 is fixed to the stern of the ship 4, and the other end is fixedly connected to the airbag reinforcement frame 5 on the first sub-airbag, and a hinge point that can move with a single degree of freedom and can be locked is set in the middle of the fixed end structure; when the platform is in working condition, the fixed end structure 1 is in a locked state; when the platform is recovered or starts to unfold, it is in a rotatable state, so that the platform can be folded and placed vertically at the stern of the ship when it is not in working condition.

[0037] The remote control valve 13 is installed at the junction of each sub-airbag, and the sub-airbags are contracted and deployed in sequence through the cooperation of each valve.

[0038] The airbag steel cable support structure includes an airbag reinforcement frame 5 and support ribs 6, wherein the shape of the airbag reinforcement frame 5 is the same as the cross-sectional shape of the airbag, is attached to the surface of the airbag 2 and is fixedly connected to the airbag, and its function is to limit the maximum deformation of the airbag and increase the allowable value of the internal pressure of the airbag to improve the structural bearing capacity; each support rib 6 is a rectangular metal plate, and a through hole is opened at the upper position to allow the steel cables on both sides of the upper end of the support rib plate to pass through, and is fixedly connected to the airbag reinforcement frame 5, thereby transferring the load on the steel cable 7 at the upper end of the support rib plate to the airbag 2, and maintaining the spacing between the steel cables at the upper end of the support rib plate unchanged.

[0039] The flexible steel cable is composed of five steel cables 7 at the upper end of the support rib and two steel cables 8 at the lower end of the airbag reinforcement frame. The middle three of the five steel cables 7 at the upper end of the support rib are fixedly connected to each support rib 6, and the steel cables on both sides pass through the through holes on each support rib; at the first sub-airbag, the steel cables on both sides of the upper end of the support rib and the steel cables 8 at the lower end of the airbag reinforcement frame are connected to the rope control system; at the terminal airbag, the steel cables 7 at the upper end of the support rib and the steel cables 8 at the lower end of the airbag reinforcement frame are both fixed on the terminal rib, forming a form of axial circumferential winding of the flexible steel cable along the airbag 2, using the inflated airbag 2 to provide axial and normal support stiffness, using the steel cables 7 at the upper end of the support rib to bear the tensile load generated in the steel cables after the platform is loaded, using the axial stiffness of the airbag 2 to bear the compressive load, and using the normal stiffness of the airbag 2 to provide normal support for the overall structure, thereby simulating the upper and lower edge strips and webs of the engineering beam respectively, thereby achieving the goal of bearing bending moment as the main load in the structure.

[0040] The airbag 2 is composed of twelve sub-airbags connected end to end in the axial direction. The cross-sectional shape of each sub-airbag is two intersecting outer contour parts that pass through the center of each circle. The junction of each sub-airbag is located at the airbag reinforcement frame 5, ensuring good airtightness and preventing the landing platform from twisting when the aircraft lands under poor centering conditions; an inflation and deflation system 10 is provided at the first sub-airbag, and is connected to the fixed end structure 1 through the airbag reinforcement frame.

[0041] The flexible braided belt 3 is wrapped around the upper end steel cable 7 of the support rib, thereby providing support for the aircraft and transmitting the impact load generated when the aircraft lands to the upper end steel cable 7 of the support rib and the lower end steel cable 8 of the airbag reinforcement frame, the support rib 6, the airbag reinforcement frame 5 and the airbag 2 in sequence.

[0042] A limiting hole 11 is provided at the bottom end of the airbag reinforcement frame 5 to prevent the steel cable 8 at the lower end of the airbag reinforcement frame from slipping when the platform is running.

[0043] The airbag material is a nylon-rubber composite material, which ensures that it has sufficient axial tensile rigidity, good air tightness and high flexibility.

[0044] The working principle of the fixed-wing UAV shipborne inflatable recovery platform provided by the present invention is as follows:

[0045] Reference Figure 1-Figure 5When the drone is ready for recovery, the stowed recovery platform must be deployed. First, the locking mechanism of the fixed end structure 1 is released, shifting the platform from being perpendicular to the aft deck to being parallel to the aft deck. The fixed end structure 1 is then adjusted again to lock it, keeping all remote control valves 13 closed. The rope control system 9 then pulls the steel cables on either side of the upper support ribs and the steel cables 8 at the lower end of the airbag reinforcement frame. Simultaneously, the inflation and deflation system 10 inflates the root airbag, gradually deploying the first airbag at the base. Once the first sub-airbag has built up adequate pressure, the axial force generated by the internal pressure and the tension generated by the steel cables on either side of the upper support ribs and the steel cables 8 at the lower end of the airbag reinforcement frame are balanced. The remote control valve between the first and second sub-airbags is then opened, inflating the second airbag, deploying the first two sub-airbags. Repeat this process until all twelve sub-airbags are fully deployed. When each sub-airbag is deployed to a fixed position, the rope control system 9 fixes the four steel cables, and the inflation and deflation system 10 maintains a constant internal pressure value of the airbag 2. At this point, the recovery platform is deployed.

[0046] When the drone is recovered, the inflation and deflation system is required to remain operational, and all remote control valves are in the open state to maintain a constant internal pressure in each sub-airbag to prevent the airbag from being damaged due to excessive internal pressure. In addition, the ship's attitude is required to be stable and the drone is well centered to prevent excessive torsion of the structure. The remaining conditions are the same as those for traditional runway landings. During the drone recovery process, the drone to be recovered contacts the flexible braided belt 3 of the recovery platform at a certain horizontal and vertical speed. It should be noted that due to the high-pressure environment established inside the airbag 2, pre-tensioned stress is generated in the upper steel cable 7 of the support rib and the lower steel cable 8 of the airbag reinforcement frame. Therefore, the flexible braided belt 3 wrapped around the steel cable 7 has sufficient rigidity to withstand the impact load applied by the drone. The braided belt 3 then transfers the concentrated load at the tire to the five steel cables 7 at the upper end of the support ribs around which it is wrapped. These cables then transfer the load to the adjacent ribs 6 and the airbag reinforcement frame 5. Finally, the load is transferred via the upper cables 7 at the support ribs, the lower cables 8 at the airbag reinforcement frame, and the airbag 2 to the fixed end structure 1 at the base of the platform, which is connected to the ship. After contacting the recovery platform, the drone uses its own braking system to slow down, finally reaching the ship's deck via the deck cover 12 at the edge, completing the recovery mission.

[0047] After the drone is recovered, the integrity of all systems is checked, and the platform is recovered. During the platform recovery process, the remote control valves are first closed to maintain the independent and constant internal pressure of each airbag. Then, the cable control system 9 pulls the steel cables on both sides of the upper end of the support rib and the lower end of the airbag reinforcement frame. This inevitably causes the internal pressure of the first sub-airbag to increase, and the inflation and deflation system 10 then autonomously deflates the first sub-airbag, thereby recovering it. After the first sub-airbag is recovered, the remote control valve between the first and second sub-airbags is opened, and the cable is pulled and deflated to recover the second sub-airbag. This process is repeated, and all 12 sub-airbags are recovered in sequence. Maintaining constant internal pressure during the retraction process by the cable is intended to maintain the support function of each sub-airbag and prevent the platform from collapsing. By sequentially deflating the sub-airbags, the platform recovers along its axis. Each sub-airbag collapses inward, and the airbag reinforcement frame is connected at the top, enveloping and protecting each sub-airbag. Finally, the recovered 12-section airbags are rotated to hang on the rear deck by rotating the fixed end 1, and the cover plate 12 is finally removed to complete the recovery of the platform.

[0048] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with this technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present invention, and these modifications or replacements should all be included in the scope of protection of the present invention.

Claims

1. A ship-borne inflatable recovery platform for fixed-wing UAVs, wherein the fixed-wing UAVs are medium to large UAVs, characterized in that It includes a fixed end structure, an airbag cable support structure, a flexible steel cable, an airbag, a flexible braided belt, a cover, a remote control valve and a rope control system; the fixed end structure is fixedly connected to the airbag reinforcement frame on the stern of the ship and the first sub-airbag; the airbag cable support structure is connected to the airbag and the flexible steel cable; the airbag is composed of twelve sub-airbags connected end to end in the axial direction, and a remote control valve is installed at the junction of each sub-airbag, and an inflation and deflation system is set at the first sub-airbag and connected to the fixed end structure; the flexible braided belt is wrapped around the upper end of the supporting rib The rope control system is used to control the steel cables on both sides of the upper end of the supporting ribs and the steel cables at the lower end of the airbag reinforcement frame; the fixed end structure is a hinge structure, and when the platform is in working state, the fixed end structure is in a locked state; when the platform is recovered or begins to unfold, it is in a rotatable state, so that the platform can be folded and placed vertically at the stern of the ship when it is not in working state; the airbag cable support structure includes multiple airbag reinforcement frames and multiple supporting ribs, wherein the shape of the airbag reinforcement frame is the same as the cross-sectional shape of the airbag, and is attached to the surface of the airbag and fixed to the airbag. Connection; Each supporting rib is a rectangular metal plate, with a through hole at the upper position allowing the steel cables on both sides of the upper end of the supporting rib to pass through, and is fixedly connected to the airbag reinforcement frame, so as to transmit the load on the steel cables at the upper end of the supporting rib to the airbag and maintain the spacing between the steel cables at the upper end of the supporting rib unchanged; a limited hole is provided at the bottom end of the airbag reinforcement frame to prevent the steel cables at the lower end of the airbag reinforcement frame from slipping when the platform is running; the flexible steel cable consists of five steel cables at the upper end of the supporting rib and two steel cables at the lower end of the airbag reinforcement frame, and the middle three of the five steel cables at the upper end of the supporting rib are connected to the airbag Each supporting rib is fixedly connected, and the steel cables on both sides pass through the through holes on each supporting rib; at the first sub-airbag, the steel cables on both sides of the upper end of the supporting rib and the steel cables at the lower end of the airbag reinforcement frame are connected to the rope control system; at the terminal airbag, the steel cables at the upper end of the supporting rib and the steel cables at the lower end of the airbag reinforcement frame are fixed on the terminal rib, forming a form in which flexible steel cables are wound in a circular direction along the axis of the airbag; the cross-sectional shape of each sub-airbag is the outer contour of two intersecting circles that pass through each other's centers, and the junction of each sub-airbag is located at the airbag reinforcement frame; the sub-airbag material is a nylon-rubber composite material.

2. A method for deploying a fixed-wing UAV shipborne inflatable recovery platform according to claim 1, characterized in that: The locking mechanism of the fixed end structure is released, and the platform is changed from being attached to the hull perpendicular to the rear deck to being parallel to the rear deck. The fixed end structure is adjusted to lock it, and all remote control valves are kept closed. The steel cables on both sides of the upper end of the support rib and the steel cables at the lower end of the airbag reinforcement frame are then pulled through the rope control system. At the same time, the first sub-airbag is inflated using the inflation and deflation system, thereby gradually deploying the first sub-airbag. When the appropriate pressure is built up for the first sub-airbag, the first sub-airbag is in a state of equilibrium due to the axial force generated by the internal pressure and the tension generated by the steel cables on both sides of the upper end of the support rib and the steel cables at the lower end of the airbag reinforcement frame. The remote control valve between the first sub-airbag and the second sub-airbag is then opened to inflate the second sub-airbag, thereby deploying the first two sub-airbags. The above operation is repeated until all 12 sub-airbags are fully deployed in sequence. When each sub-airbag is deployed to a fixed position, the rope control system secures the steel cables on both sides of the upper end of the support rib and the steel cables at the lower end of the airbag reinforcement frame, and the inflation and deflation system maintains a constant internal pressure value in the airbag.

3. A method for recovering a fixed-wing UAV shipborne inflatable recovery platform according to claim 1, characterized in that: First, close each remote control valve to keep the internal pressure of each sub-airbag independent and unchanged, and then pull the steel cables on both sides of the upper end of the supporting rib and the steel cable at the lower end of the airbag reinforcement frame through the rope control system. At this time, the internal pressure of the first sub-airbag increases, and then the inflation and deflation system automatically deflates the first sub-airbag, thereby realizing the recovery of the first sub-airbag; after the first sub-airbag is recovered, open the remote control valve between the first sub-airbag and the second sub-airbag, pull the steel cable and deflate the second sub-airbag to realize the recovery of the second sub-airbag; repeat the above operations to recover the 12 sub-airbags in turn; finally, rotate the recovered 12 sub-airbags to hang on the rear deck through the rotation of the fixed end structure.

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