FR3033769A1 - DEVICE AND METHOD FOR ASSISTING THE LANDING PHASE OF A FIXED SAIL AIRCRAFT - Google Patents

Abstract

The invention relates to a recovery device (30) and a method for assisting the landing phase of a fixed-wing aircraft (20) (21), said aircraft comprising a fuselage (22), where said device recovery device (10) comprises a position mark (31) adapted to be identified by a sensor of the aircraft and a friction brake means (32) adapted to apply a surface force to at least a part of the surface of the fixed wing (21).

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a landing aid device for an aircraft, as well as to a method of landing the aircraft. Among the aircraft, fixed wing aircraft, among which, aircraft without pilots or drones, are particularly known. The large flight capabilities of this type of aircraft and their small size make them all the more difficult to install. STATE OF THE ART Fixed-wing aircraft are generally equipped with a fuselage carrying at least one propulsion means, usually a main rotor, which propels the aircraft. This type of aircraft is generally equipped with very large flight control surfaces compared to its size. For all aircraft and more particularly fixed-wing aircraft, the landing phase is one of the most critical. Landing on a small surface is a major issue faced by all fixed-wing aircraft. This is an extremely complex exercise in the case of an unmanned aircraft, also called drone in the following description, drone. We note that in recent years have seen the landing of drones in small spaces especially on the pontoon of an aircraft carrier. These landings are made by means of a stop cable also called stop line. The drone is equipped with a landing gear as is also the case for fixed-wing aircraft with pilot such as fighter planes. This type of landing is possible only for large aircraft such as the X-47B drone with a wingspan of nearly 20 meters, for a take-off weight of more than 20 tons. Indeed, the attachment between the stopping strand and the landing gear of the aircraft requires a very high accuracy in approach. This is made possible by the great stability of large aircraft. This technique is very delicate, because it must be ensured that the landing gear of the aircraft does not get caught in the stop cables before the landing gear. Speed is also a crucial element: too fast, it prevents stopping or makes it extremely brutal; too slow, it will do that if the stick does not catch a cable, the plane will miss speed to take off and crash.

3033769 2 This type of landing is therefore not suitable for smaller aircraft whose aerodynamic performance is high (high finesse) but particularly subject to external conditions. A low approach slope, even in gliding, implies that it is difficult with this type of aircraft to land at a specific point on the ground. It is therefore necessary to use relatively long landing strips and properly maintained. The problem underlying the invention is therefore to provide a device allowing a return to the ground for this type of aircraft at a specific point on a reduced surface for landing in any situation.

SUMMARY OF THE INVENTION The present invention aims to remedy all or part of these disadvantages. For this purpose, according to a first aspect, the present invention provides a device for assisting the landing phase of a fixed-wing aircraft. Said device 15 comprises a position mark adapted to be identified by a sensor of the aircraft and a friction braking means adapted to apply a surface force on at least a portion of the surface of the wing. It is understood that the surface strength thus created is particularly opposed to the recovery by deck rod or recovery net, known in the world of aeronautics 20. The recovery net exerts a localized force on the lines formed by the threads of the mesh, and assumes that the wing is made of a material rigid enough to absorb the force thus applied, without irreversibly deforming, the dissipation of kinetic energy. being concentrated on a very weak surface of the wing.

On the contrary, the use of a surface friction force capturing means on the wing means that the kinetic energy dissipation takes place over a much larger area, which considerably reduces the stress on the choice of the material. constituting the wing. The term fixed-wing aircraft is used herein as opposed to a rotary-wing aircraft. Furthermore, the term "drone" in the remainder of the description, the fixed wing aircraft thus referred. The term "recovery device" also designates the device for assisting the landing phase of a drone.

3033 769 3 The recovery device thus provides a large surface for the mechanical capture of the drone, which allows to quickly stop said drone with a device of small dimensions. The advantage over a stop-stop type stop device, coupled with a landing gear, is that the aircraft can approach with less accuracy. The mechanical capture means of the fixed wing makes it possible to stop the aircraft without risk of damaging the structure as can be the case on a small aircraft whose attachment by a single point such as a landing gear may deteriorate the fuselage at the moment of deceleration.

In a particular embodiment, the capture means is composed of two capture elements, intended to come into contact with the wing, between which the wing of the aircraft will be inserted. In a particular embodiment, the capture means is composed of two pairs of capture elements, each of the pairs being intended to receive the insertion of a portion (right, left) of the fixed wing. In a particular embodiment, the two pairs of capture elements are interconnected by a lower connecting element and an upper connecting element intended to come into contact with the fuselage.

20 With these provisions, each part of the aircraft; Fixed wing and fuselage come into contact with the mechanical catching elements of the device and the entire aircraft is thus slowed down to a complete stop. In a particular embodiment, the capture elements, in which the wings of the aircraft will be inserted, form an angle of between 0 degrees and 45 degrees, said angle being open on the arrival side of the aircraft. aircraft. With these provisions, the aircraft can be guided by the device and the capture elements will be able to perform a gradual squeeze of the wing of the aircraft.

More particularly in this case, the angled capturing elements are extended by parallel stop elements. Thanks to these arrangements, the aircraft is guided to the parallel stopping elements which allow to finish slowing down the speed of the aircraft until the complete stop.

In a particular embodiment, said capture elements are covered with flexible patterns having a high coefficient of friction. With these provisions, the flexible patterns cover the part of the elements intended to come into contact with the wing of the aircraft.

In a more particular embodiment, said flexible patterns are brushes made of bristles or foam volumes. Thanks to these provisions, the high density of hair gives the brushes constituting the capture elements a great flexibility and a high coefficient of friction that allows guiding and slowing down until the complete stop of the aircraft.

In a particular embodiment, said marker is a visual cue adapted to be identified by a camera on board said aircraft. With these arrangements, the aircraft can be guided to the recovery device with a single camera and does not require remote control pilot support. According to a second aspect, the present invention relates to a landing method of a fixed-wing aircraft, with the aid of a recovery device comprising a position mark capable of being identified by the aircraft and a means of 20 friction brake adapted to apply a surface force on at least a portion of the surface of the wing, the aircraft being controlled by a microcontroller connected to an electronic circuit, the method comprising steps of: i) perception and identification of the reference mark of the recovery device by the aircraft, ii) execution of an approach program of the aircraft towards the recovery device, iii) contact between the recovery device and the wing of the aircraft, iv) stopping of the aircraft. With these arrangements, a fixed wing aircraft can be stopped without using a runway for a minimum distance without risk to the physical integrity of the aircraft. In an alternative embodiment, the method also comprises a step of retraction fins and flaps just before contact between the recovery device and the wing. This arrangement makes it possible to avoid breaking said flaps or flaps during the impact. BRIEF DESCRIPTION OF THE FIGURES Other advantages, aims and features of the present invention will emerge from the description which follows, made for explanatory and non-limiting purposes with reference to the accompanying drawings, in which: FIG. very schematic, the recovery device and a drone in approach, viewed from three quarters, - 2 shows the recovery device seen in section in an alternative embodiment, - Figure 3 shows a view of three quarters of a another variant embodiment of the drone recovery device.

DESCRIPTION OF EXAMPLES OF THE INVENTION It is noted, as of now, that the figures are not to scale. As can be seen for example in FIG. 1, in a nonlimiting example of implementation of the invention, the present invention relates to a recovery device 30 for assisting the landing phase of an aircraft 20 to fixed wing 21 (called drone in the following description), said drone 20 comprising a fuselage 22 and at least one propulsion means (not shown but assumed to be known to those skilled in the art and coming out as such part of the invention). The recovery device 30 comprises a position mark 31 adapted to be identified by a sensor (not shown) of the drone 20 and a mechanical capture means 32 of said wing 21 of the drone 20. The wing 21 provides a large surface for the mechanical capture of the drone 20 by the recovery device 30, which allows to quickly stop the aircraft 20 with a recovery device 30 of small dimensions, that is to say typically close to or less than the wingspan of the drone.

By mechanical capture means any means of effecting a mechanical capture of the wing 21 in a progressive manner so as to slow the drone 20 until the complete cessation of said drone 20. The mechanical capture means 32 advantageously causes a incremental friction as the drone 30 penetrates deeper into the recovery device 30, causing it to decelerate to a complete stop. In the present nonlimiting exemplary embodiment (see FIG. 2), the capture means 32 comprises a lower capture element 321 and an upper capture element 322, in which the wing 21 of the drone 20 is inserted during the capture. The lower capture member 321 is intended to contact the lower face of the wing 21, and likewise the upper capture member 322 is intended to contact the upper face. of the wing. The mechanical capture elements 321 and 322 may also come into contact with the fuselage 22 of the drone 20. In the present nonlimiting embodiment, forming a variant illustrated in FIG. 3, the capture means 32 is composed of two pairs of elements. capture 321a, 322a left and 321b, 322b right. Each of these pairs of capture elements is intended to receive the insertion of a portion of the fixed wing 21, respectively the part to the left of the fuselage 22, and the part to the right of the fuselage 22. The two pairs of capture elements 321a, 322a left and 321b, 322b right 20 are interconnected by a lower connecting member 341 and an upper connecting member 342, intended to come into contact with the fuselage 22. Each of the parts of the drone 20: fixed wing 21 and fuselage 22, comes into contact with the mechanical catching elements 321 and 322 and the lower link members 341 and 342 of the recovery device 30, and the drone 20 is thus slowed down until it stops completely. relative to the recovery device 30. In the present example, the capture elements 321 and 322, in which the wing 21 of the drone 20 is inserted, form between them an angle of the order of 35 °, and more genius. typically between 0 degrees and 45 degrees, said angle being open on the arrival side of the drone 20. The drone 20 can thus be guided by the recovery device 30 and the capture elements 321 and 322 carry out a progressive squeeze of the wing 21 of the drone 20. In an advantageous embodiment, the skilled person adjusts the angle of the capture elements 321 and 322 according to the dimensions of the fixed wing 21 and the model of the drone 20 for which the recovery device 30 is put in place. Preferably, the recovery device 30 includes adjustment means (not shown) for the spacing and tilt angle between the catch elements 321 and 322. In the present embodiment, the catch elements 321 and 322, at an angle are extended by lower parallel 351 and upper 352 stop members (see Figure 2). The capture elements 321 and 322 allow the guidance of the drone 20 within the recovery device 30, while causing a reduction in the speed of said drone 20. The drone 20 is guided to the parallel arrestors, lower 351 and upper 352, which make it possible to finish reducing the speed of the drone 20 until it stops completely, while keeping the drone 20 in a horizontal position.

In the present exemplary embodiment, said capture elements 321 and 322 are covered with flexible patterns 33 having a high coefficient of friction, the flexible patterns 33 covering the portion of the capture elements 321 and 322 intended to come into contact with the wing. 21 of the drone 20.

By "flexible" is meant elements capable of elastically deforming their initial shape under the action of an external force and able to return, once this force is no longer exerted, to their original shape. "Patterns" means surface reliefs of the capture elements placed so as to be able to come into contact with the fixed wing of the drone 20. Of the 25 flexible patterns 33 that may be chosen, here we consider not cause damage to the wing and the fuselage 22 of the drone 20, while allowing to slow the speed of the drone 20 at the time of landing. The flexible patterns 33 are for example excrescences of any shape, made of flexible material, such as in particular natural or synthetic rubber.

Likewise, the lower parallel and upper 351 stop elements 352 are covered, in the present example embodiment, with second flexible units 33 'having a high coefficient of friction. In the present example, these second flexible patterns 33 'are identical to the flexible patterns 33. In an alternative embodiment, the flexible patterns covering the lower parallel stop elements 351 and 353 and upper 352 are not identical to the flexible patterns 33 covering the capture elements 321 and 322. Their coefficient of friction may in particular be different. In the present example, said flexible patterns 33, 33 'are brushes consisting of bristles 331.

The high pile density 331 thus gives the brushes, constituting the flexible patterns 33 covering the capture elements 321 and 322, and the flexible patterns 33 'covering the lower parallel 351 and 352 upper stop elements, a great flexibility and a coefficient high friction which allows guiding and slowing down to the complete stop of the drone 20 without risk of damage to the wings 21 or the fuselage 22. In another implementation of the recovery device, it consists of a foam block having a set of slots. In a nonlimiting example of implementation, these slots are flat, parallel and substantially horizontal facing the direction from which the drone must come. Alternatively, it may also act of a set of foam blocks stacked on each other vertically and secured, this set comprising for example half a dozen blocks of foam substantially parallelepiped.

In these embodiments, the drone is inserted, during the impact, between two foam layers, and the kinetic energy of the flight is dissipated in the form of deformation of the foam and optionally displacement by sliding of the foam block. On the ground. In another variant, the recovery device consists of a honeycomb block 25 formed of cardboard sheets, the device comprising a central recess adapted to allow the passage of the fuselage, while the wings come to bear on the sheets cardboard and fold these when transferring energy between the drone and the recovery device. Here again, the recovery device may be left free to slide on the ground during recovery, part of the kinetic energy of the drone being dissipated by the plastic deformation of the cardboard block, and the other part of this kinetic energy being dissipated by the sliding of the block on the ground.

In the present embodiment, the position mark 31 is a visual cue, suitable for identification by a video camera (not shown) on board the UAV 20. The UAV 20 is here guided to the recovery device. 30 using a video camera and a control algorithm implemented by calculation means (advantageously but not necessarily on board the drone 20), and does not require the support of a pilot through a remote control system. In the case of an unmanned drone 20, the recognition and identification of the position mark 31 is carried out via a microcontroller (not shown) which will make it possible to adjust the automatic landing phase. . Detection of the recovery device 30 by an image processing method is initiated during the landing phase. Once the position mark 31 is spotted with sufficient confidence, the drone 20 enters a specific state and pilot observation mode. The coordinates of the position marker 31 of the recovery device 30 in the image plane are determined by the camera and an image processing module. These coordinates are used in a fusion algorithm to observe the relative position of the drone 20 with respect to the recovery device 30 with high accuracy.

If this position of the drone 20 is determined to be outside an acceptable envelope to make the return to the ground, the drone 20 cancels its landing and maneuver to return to an acceptable position with respect to the position mark 31. The reference in an alternative embodiment, a position 31 may be a signal 25 emitted by the recovery device 30 and received by the drone 20. The landing method of the fixed-wing drone 21 using the recovery device 30 comprises the steps of: i) perception and identification of the mark 31 of the recovery device 30 by the drone 20, ii) setting up an approach program towards the recovery device 30, iii) contact between the device recovery 30 and the wing 21 of the drone 20, iv) stopping the drone 20.

As a result of the plane landing of the drone 20, the trajectory of the drone 20 relative to the recovery device 30 is very dependent on the wind. The trajectory of the drone 20 is determined during the first phase of the final, as follows: 1. An accurate estimate of the headwind is made (by difference between the relative speed of the drone 20 and its speed relative to the ground which both are known). 2. According to this wind, an approach plane is chosen, according to the known finesse of the drone 20. 3. Then a trajectory is generated, such as a polynomial function of the altitude setpoint as a function of the distance to the end point. 4. Once at the starting point of the final trajectory, the drone 20 begins its final altitude loss to go to the device 30. 5. The aircraft comes into contact with its wings 21 with the aircraft. capture elements 321 and 322 slow down its speed until it stops. Advantageously, the flaps and fins are retracted just before the impact of the drone on the recovery device.

In an exemplary implementation, the perception of the recovery device 30 by the drone 20 is performed by a visual sensor, for example video camera type (not shown) embedded on the drone 20, directed forward. The position mark 31 is here composed of printed images, which can be identified by image processing and disposed on the recovery device 30, and serves as a target for guiding the drone 20 during the final phase of the landing. The drone 20 proceeds to its usual approach vis-a-vis the recovery device 30, and is positioned on a final segment of 300 meters, with as an approximate end point the position of the recovery device 30 30 (GPS coordinates + altitude) . A control law, intended to target the recovery device 30, is applied to the controls of the drone 20.

In an alternative embodiment, the position marker 31 is composed of light elements that can be identified by image processing, arranged on the recovery device 30.

The drone 20 performs its approach automatically. During the final phase of the landing, it detects the position mark 31. The drone 20 then enters a control phase whose objective is to aim the recovery device 30 until contact.

The recovery device 30 is thus a mechanical and electronic device performing two functions: during the final phase of the landing: it provides the drone with a position indicator 31 which allows the drone 20 to control its trajectory with precision, direction of the recovery device 30, 15 - At the moment when the drone 20 comes into contact with the recovery device 30, the latter mechanically captures the drone 20 and ensures its deceleration to a stop, while preserving its mechanical integrity. In an alternative embodiment, the recovery device is integrated into a deployment / recovery station which performs the following functions: Communication with the drone (pointer antenna foot) Protection of the drone against the elements (storage of the drone in a shelter ) Automatic ramp takeoff 25 Automatic landing in a trap Rebuilding the drone (recharging the batteries, moving the drone from its landing position to its take-off position, reloading the ramp). Automatic wind direction for the drone to take off and land in the wind. Remote communication with the user of the drone (ex: control station of an industrial infrastructure, departure on order by command button). General Description: 3033769 12 The deployment / recovery station is located on a mat whose access is possibly restricted by a barrier. The deployment / recovery station is in the form of a keypad that can contain a drone.

5 The deployment / recovery station is equipped with a wind vane and an anemometer to know the aerological conditions at the time of deployment. The pavement is swiveling, so that the takeoff and landing can face the wind. Energy is provided by a storage battery and a solar panel.

NOMENCLATURE 20 aircraft, 15 21 wing, 30 recovery device, 31 position indicator, 32 capture means, 321 lower capture element, 322 upper capture element, 321a, 322a pairs of left capture elements, 321b, 322b pairs of straight capture elements, 33 flexible patterns, 33 'second flexible words, 331 bristles, 341 lower link, 342 upper link, 351 lower stop, 352 upper stop.

Claims (14)

REVENDICATIONS1. Device (30) for assisting the landing phase of a fixed-wing aircraft (20) (21), said aircraft comprising a fuselage (22), characterized in that said device (10) comprises a reference mark position (31) adapted to be identified by a sensor of the aircraft (20) and a friction brake means (32) adapted to apply a surface force on at least a portion of the surface of the fixed wing (21). 2. Device according to claim 1, characterized in that the capture means (32) is composed of two lower capture elements (321) and upper (322), between which the wing (21) of the aircraft ( 20) is inserted. 3. Device according to claim 1 or 2, characterized in that the capture means (32) is composed of two pairs of left capture elements (321a, 322a) and right (321b, 322b). 4. Device according to claim 3, characterized in that the two pairs of capture elements are interconnected by a lower connecting member (341) and upper (342). 5. Device according to claim 1, characterized in that the capture means (32) is composed of a foam block having a set of parallel plane slots. 6. Device according to one of claims 2 to 4 wherein the capture elements (321) and (322), in which the wing 21 of the aircraft will be inserted form an angle of between 5 and 45 degrees, said angle being open on the arrival side of the aircraft. 7. Device according to claim 6, characterized in that the capture elements (321) and (322), are extended by lower arresting elements (351) and upper (352) substantially parallel. 3033769 14 8. Device according to any one of claims 2 to 7, characterized in that said capture elements (321) and (322) are covered with flexible patterns (33) having a high coefficient of friction. 5 9. Device according to any one of claims 2 to 8, characterized in that the lower parallel stop elements (351) and upper (352) are covered with flexible patterns (33) having a high coefficient of friction. 10. Device according to any one of claims 1 to 9, characterized in that said flexible patterns (33 ') are brushes consisting of bristles (331). 11. Device according to any one of claims 1 to 10, characterized in that said mark (31) is a visual cue adapted to be identified by a camera onboard said aircraft (20). 15 12. Method for landing a fixed-wing aircraft (20) with a device (30) comprising a position mark (31) suitable for identification by the aircraft and a means for mechanical capture (32) of said aircraft according to one of claims 1 to 11, the aircraft being driven by computing means, characterized in that the method comprises the steps of: i) perception and identification of the position mark (31 ) of the recovery device (30) by the aircraft (20), ii) execution of an approach program of the aircraft (20) towards the recovery device (30), iii) contact between the recovery (30) and the wing (21) of the aircraft (20), iv) stopping the aircraft (20) relative to the recovery device (30). 13. Station for recovery aircraft (20) to fixed wing (21), type drone, characterized in that the station comprises a device according to any one of claims 1 to 11, and automatic battery charging means of said drone. 3033769 15 14. drone recovery station according to claim 13, characterized in that it comprises means: E communication with the drone, E protection of the drone against the weather, 5 E automatic takeoff on ramp, reconditioning E of drone (including at least one of the following functions: moving the drone from its landing position to its take-off position, refilling the ramp), E automatically facing the wind.