RU2307047C1 - Method of landing superlight unmanned flying vehicles - Google Patents

Abstract

FIELD: aviation industry.

SUBSTANCE: invention relates to methods of landing of unmanned flying vehicles particularly, superlight unmanned flying vehicles, mass not exceeding one kilogram, furnished with electronic observation, navigation and flight control devices. According to proposed method, before beginning of flight, beacon transmitter with impact sensor is installed on unmanned flying vehicle made for fixing moment of contact of unmanned flying vehicle with ground at switched off power unit, and horizontal flight of unmanned flying vehicle overland is carried out. Unmanned flying vehicle is directed to landing area according to preset program or by remote control from ground. After bringing unmanned flying vehicle into landing area, its power unit is switched off and fall of unmanned flying vehicle under gravity is provided. At moment of contact of unmanned flying vehicle with ground, beacon transmitter is activated by signal from impact sensor. Location of landed unmanned flying vehicle is determined by radio direction finding of beacon transmitter and vehicle is searched for following evacuation. Simplified to maximum landing procedure of unmanned flying vehicle according to proposed method makes it possible to dispense with complex on-board electronic guidance equipment and landing optical devices on ground.

EFFECT: possibility of landing on any unequipped ground areas.

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Description

The invention relates to methods for landing unmanned aerial vehicles (UAVs), in particular to methods for landing ultralight (weighing no more than one kilogram) UAVs equipped with on-board electronic devices for monitoring, navigation and automatic flight control.

A known method of landing UAVs using a parachute system (for example, the newsletter "Foreign press on the economic, scientific, technical and military potential ...", a series of "Technical means of intelligence services of the capitalist states", Moscow, No. 6, 1998, p.21 ), in which the parachute system is pre-installed on the UAV, the parachute is opened during landing, and with it, the UAV landing speed is suppressed to an acceptable value.

The disadvantage of this method is the increase in the total mass of the UAV due to the mass of the parachute system, leading to the need to significantly reduce the mass of the payload. Due to the indicated weight and size limitations, the use of a parachute system for landing ultralight UAVs is difficult.

Another known method for landing UAVs (both small and large masses) is based on damping the relative speed due to the landing site movement coordinated with UAV flight. This class of technical solutions includes, for example, the method of landing UAVs according to Japanese patent JP No. 2001354199, B64F 1/00, B63B 35/50, B64C 13/18. This method is based on the movement of the landing site, the role of which is played by the deck of a surface vessel (for example, ship, barge), with a speed close to the horizontal component of the speed of the UAV, in the final landing section. According to this method, the horizontal component of the speed of the UAV is measured and the speed of the vessel is adjusted so that the relative speed of approach of the UAV and the surface of the deck of the vessel tends to zero.

Obviously, this method can have very limited application, since it creates significant inconvenience for the object used as a landing site.

To eliminate this drawback, a movable platform is used as a landing pad, on which a vertical frame with a landing net is installed, which is made with the possibility of rotation around a vertical axis and horizontal movement along guides fixed to the platform. On board the UAV and on the platform, special electronic landing equipment (optical or radar) is installed. These tools allow you to remotely control the relative location and speed of approach of the UAV to the network and control both the movement of the frame with the network and the flight of the UAV at the final landing approach so that the UAV does not receive mechanical damage during landing.

So, in the known method of landing UAVs by capturing it in a vertical network, described in the review "Remote-controlled aircraft of the capitalist countries." / Edited by Fedosov EA, Moscow, Scientific Information Center, 1989, p.51-61, in the bow of the UAV set a pulsed radiation source operating in the near infrared (IR) region of the spectrum. A platform with guides is installed on the landing site, which remains stationary during the landing of the UAV. A vertical frame is mounted on the platform, made to rotate around a vertical axis, and a drive for this rotation. Two IR receivers are installed on the frame, a vertical landing network, made with the possibility of its horizontal movement along the rails mounted on the platform, a calculator and a brake device, which are connected to the network by cables. At the final section of the UAV approach by landing, by remote control from the ground, they bring it into the range of infrared receivers, measure the elevation angle and the lateral UAV offset relative to the network center, calculate the deviations of the UAV from the programmed approach path and transmit these data to UAV board to ensure it gets into the network. When the UAV enters the network, the latter is moved along the guide rails, the kinetic energy of the UAV movement is extinguished by pulling the braking device cables, and the UAV caught in it is released from the network.

As can be seen from the above description, for the implementation of the method of landing UAVs in the network requires a fairly complex and bulky ground equipment. This limits the scope of the possible application of these methods, especially in cases where the UAV should have a small cost, small weight and dimensions. For such UAVs, neither for tactical nor economic reasons the use of complex landing devices is justified.

As for the conventional aircraft method of horizontal landing, it is unacceptable for ultralight UAVs, since it requires a runway. For UAVs, the vertical landing method used by helicopters and special aircraft with vertical take-off and landing is more interesting. However, these aircraft are difficult to operate and operate, expensive and usually used only in manned aircraft.

It should be noted that in the history of aviation, numerous attempts have been made to create hybrid aircraft of unconventional patterns that could land safely anywhere on the earth’s surface (for example, P. Bauer’s book, “Unconventional Pattern Aircraft”, Moscow, Mir, 1991).

So, for example, the invention of patent RU No. 2278801, B64C 29/02, B64C 25/40 is based on the idea of using the autorotation phenomenon when landing an ultralight UAV.

According to this method, before the start of the UAV flight, electronic guidance equipment is installed on board, and ground landing equipment is placed on the landing site, horizontal flight and landing approaches are carried out in airplane mode, on the final landing site using onboard electronic guidance equipment and ground landing equipment direct the UAV to the landing site and by damping the kinetic energy of the UAV movement using the braking mechanism, the UAV is soft-landed for landing the active site — in this case, after the UAV is guided to the landing site using the power plant and aerodynamic control units, the UAVs transfer it to autorotation mode with precession with respect to the vertically directed velocity vector of its translational motion, after which the vertical speed of the UAVs is reduced using the UAVs movement relative to the ground to values that provide the possibility of complete damping of the kinetic energy of the UAV during its soft landing.

As the on-board electronic guidance equipment, a video guidance system is used containing an on-board sensor - a video module, which includes a video camera with an optical system and a video image processor. As a ground landing equipment, one or several optical reflectors are used, for example, mirrors, which are located, respectively, at the desired landing site, for example, in the form of a given geometric shape - around the perimeter or inside the landing site. To transfer UAVs into autorotation mode, the planes of its wings are synchronously rotated in opposite directions relative to their longitudinal axes by angles not exceeding 90 degrees, and after translating UAVs into autorotation, wing planes are set perpendicular to the longitudinal axis of the UAV. As a braking mechanism, a mechanical spring is used, which is installed in the nose of the UAV along the longitudinal axis of the UAV before the UAV’s flight, when the UAV lands on a command of the video guidance system, the mechanical spring is released immediately before touching the landing surface and, due to its action, completely extinguishes the kinetic energy of the UAV, providing its soft landing in vertical position.

The provided technical result consists in using the autorotation effect to reduce the vertical speed of UAV descent (parachute effect) to safe limits and at the same time using the resulting precession to scan the surface of the earth with a sensor of on-board electronic guidance equipment. With a decrease in UAVs in autorotation under the influence of air flow, its wings and body rotate like a rotor of a helicopter, creating lift. The movement of the UAV itself resembles the fall of a maple seed.

The method described above is the closest analogue of the present invention.

The disadvantage of the closest analogue is the difficulty of practical implementation of the landing procedure, requiring the use of electronic guidance equipment, as well as coordinated control of the engine, aerodynamic controls and a mechanical brake device (spring).

The present invention is aimed at eliminating the specified drawback of the closest analogue - at the maximum possible simplification of the implementation of the landing procedure.

The subject of the invention is a method for landing an ultralight UAV, in which a UAV is flown horizontally above the earth’s surface, according to a predetermined program or by remote control from the earth, UAVs are brought to the landing area, and after the UAV contacts the earth’s surface, it is evacuated from the landing area, prior to the flight of the UAV, a beacon transmitter is installed on its board with an impact sensor configured to record the moment of UAV contact with the earth’s surface when the propulsion system is off, f UAV withdrawal to the landing area turns off its propulsion system and ensures its fall under the influence of gravity, at the moment of UAV contact with the earth's surface, a beacon transmitter is activated by a signal from the shock sensor, the location of the landing UAV is determined by radio direction finding of the beacon transmitter and it is searched for subsequent evacuation .

A private significant feature is that the direction finding of the UAV beacon transmitter is carried out using equipment similar to the direction finder used in fox hunting competitions.

The objective of the present invention is the creation of such a procedure for landing an ultralight UAV, which would make it possible to do without complex electronic on-board guidance equipment and landing optical devices located on the ground.

Provided technical result consists in the possibility of landing UAVs on virtually any unequipped sections of the earth's surface.

The essence of the invention is illustrated in figure 1-figure 3.

Figure 1 presents in three projections a sketch of the construction of a possible embodiment of the ultralight UAV for the implementation of the claimed method.

Figure 2 presents an isometric projection of a modified design of an ultralight UAV for implementing the inventive method.

Figure 3 illustrates the process of finding UAVs using a portable direction finder.

In figure 1, figure 3, the following notation is used: 1 - controlled impeller; 2 - the first protective hoop; 3 - second protective hoop; 4 - central connecting node; 5 - compartment for the payload; 6 - wing; 7 - stretching; 8 - additional protective hoop; 9 - a radio receiver; 10 - direction finding antenna; 11 - headphones.

The considered ultralight UAV, which implements the claimed landing method, has an unconventional construction scheme (Fig. 1 and Fig. 2).

The ultralight UAV contains a longitudinally extended central connecting unit 4, in the rear of which a propulsion system is installed - a controlled impeller 1, and in the front part there is a compartment 5 for the payload. Wings 6 are attached to the sides of the central binder assembly 4.

The longitudinal axes of the wings 6 are perpendicular to the longitudinal axis of the central binder 4 and lie with this axis in the same horizontal plane passing through the center of mass of the central binder 4.

The controlled impeller 1 consists of a turbine driven by an engine (for example, an electric one), and this engine itself, equipped with an automatic on / off relay installed inside the turbine casing (in Fig. 1 and Fig. 2, the turbine, engine, and automatic on / off relay shutdowns are not shown).

The payload includes various electronic devices, such as an automatic flight control system, communications, navigation and video surveillance systems, as well as a beacon transmitter with an impact sensor, the operation of which is allowed only when the automatic on / off relay is off. The shock sensor detects shock when the UAV falls to the ground with the engine turned off.

The composition of the payload may vary, depending on the tasks performed by the UAV, and in this case is not specified (with the exception of the impact sensor required for the implementation of the inventive method). The Central connecting node 4 with the compartment 5 for the payload is made of durable lightweight material, for example, carbon fiber or fiberglass.

A feature of the UAV under consideration is the presence in it of a special landing gear made with the possibility of absorbing the kinetic energy of the UAV when it comes in contact with the earth's surface or with any foreign object, such as a tree or pillar.

The specified landing gear contains identical protective hoops made of rigid elastic material, for example from a carbon fiber tube. The minimum possible number of such protective hoops is two (figure 1). The first protective hoop 2 is located in a horizontal plane passing through the longitudinal axis of the central connecting unit 4. The second protective hoop 3 is located in the vertical plane also passing through the longitudinal axis of the central connecting unit 4. The first 2 and second 3 protective hoops are rigidly fastened to each other in two intersection points.

Wings 6 UAVs are made of durable synthetic fabric, such as lavsan. Each wing 6 is a strip of strong fabric, one edge of which is attached to the corresponding side of the central binder 4, and the other is pulled onto the opposite segment of the first protective hoop 2, is bent and hemmed to the wrong side of the same wing 6. The places of such hemming are shown by dotted lines figure 1 (top view). Due to the elasticity of the first protective hoop 2, the fabric of the wings 6 is always in a tense state.

The upper and lower points of the first protective hoop 2 are connected to the central connecting unit 4 by braces 7 made, for example, in the form of pins from a carbon fiber tube or stretched (due to the elasticity of the second protective hoop 3) strong elastic cables made of synthetic material (for example, lavsan). Stretch marks 7 are located on the same axis with the transverse axis of the Central connecting node 4, passing in a vertical plane through its center of mass.

In the embodiment shown in FIG. 2, the first 2 and second 3 protective hoops are supplemented by several identical additional protective hoops 8. Each additional protective hoop 8 is, like the second protective hoop 3, in a vertical plane. But the location planes of each of the additional protective hoops 8 are rotated around the transverse axis of the central connecting unit 4 by an angle relative to the plane in which the second protective hoop 3 is located. Each additional protective hoop 8 is rigidly fastened to the first 2 and second 3 protective hoops at the intersection points with them.

Thus, the design of the UAV has both rigidity and elasticity. The rigidity of the entire UAV design is a prerequisite for a stable controlled flight. Elasticity is a necessary and sufficient condition for the "softening" of the shock during landing or in collision with foreign objects. The use of additional protective hoops 8 (figure 2) increases the degree of rigidity and elasticity of the design of the UAV. In addition, the probability of UAV damage in a collision with a small object on the ground is reduced, in which this object can slip past the first 2 and second 3 protective hoops and damage the central connecting unit 4. It is obvious, however, that the use of additional protective hoops 8 (Fig. 2 ) makes UAV heavier and leads to a deterioration in its aerodynamic characteristics. Therefore, in practice, the choice of the number of additional protective hoops 8 should be the subject of a reasonable compromise between flight performance and UAV safety, taking into account the tasks it solves.

The UAV landing procedure also includes the operator’s actions to search for a UAV that has landed and rolled in an unknown direction on the earth’s surface. A UAV can roll under a tree or get stuck in dense grass and be invisible to the operator.

To speed up the search, use the radio search equipment that the operator is equipped with. For example, the simplest direction finder used in well-known fox hunting competitions can be used. Information about the specified equipment is given, for example, on the website www.urfiwz.grz.ru.

The direction finder used in "fox hunting" is a radio receiver 9 with a direction finder antenna 10 and headphones 11.

In this case, can be used the simplest version of the construction of a portable direction finder, shown in Fig.3.

By turning the antenna 10 of the direction finder, the operator can determine the direction (azimuth) to the radiation source corresponding to the maximum volume (or repetition frequency) of the signals heard in the headphones. The distance to the UAV can also be roughly estimated, for example, by the frequency of the audible sound signals. For more accurate measurements, an indicator, such as a compass type pointer, can be used.

The proposed method of landing the above-described variant of an ultralight UAV is as follows.

After completing a flight mission, UAVs are, for example, discharged according to a predetermined program to the area of intended landing in which the operator is located. At a given point, the propulsion system, the role of which in the considered version of the UAV construction is played by the controlled impeller 1, is turned off. Under the influence of gravity, the UAV begins to decline rapidly, while maintaining the horizontal component of the speed of movement, that is, to fall down along an inclined path.

When touching the ground, the first 2 and second 3 protective hoops are rigidly bonded to each other with the earth's surface. The first 2 and second 3 protective hoops bend, deformation occurs in them, in which the first 2 and second 3 protective hoops tend to push off from the earth's surface.

The horizontal component of the speed of the UAV does not change upon contact with the earth's surface. The UAV continues to move, however, the braking force of friction begins to act on the lower part of the hoops. In addition, the design of the UAV is also affected by gravity directed vertically downward. The UAV goes into rolling mode, that is, it begins to roll on the surface of the earth, like a ball. In this case, the UAV can jump several times, and then stop. During this braking of the UAV, the central coupling unit 4 (with the controlled impeller 1 and compartment 5 for the payload rigidly connected to it) continues its inertia movement. However, this movement is inhibited by the elastic force of both the wings 6 and the stretch marks 7.

Without reaching the first 2 and second 3 protective hoops, the central connecting unit 4 stops inside the UAV structure. At the same time, the first 2 and second 3 protective hoops are repelled from the ground. However, due to the movement of the central connecting unit 4 inside the UAV structure, the repulsion of the first 2 and second 3 protective hoops from the ground is inelastic. Inside the UAV, the central connecting unit 4 goes into reciprocating motion with decreasing amplitude. This movement is due to the elasticity of both wings 6 and stretch marks 7. In the end, the UAV stops, and the reciprocating movement of the central connecting unit 4 inside the UAV structure stops. As a result, the UAV is close to the point of initial contact with the surface of the earth, and the body of the central UAV connecting unit 4, the controlled impeller 1, wings 6, and the equipment located in the payload compartment of the central connecting unit 4 remain intact. This is due to the presence of elastic internal vibrations of the Central connecting node 4, leading to a decrease in the resulting overload for the payload of the UAV.

Unlike other known methods of landing ultralight UAVs with unconventional construction schemes (for example, according to patents RU No. 2278801, B64C 29/02, B64C 25/40, B64F 1/18 and RU No. 2278060, B64F 1/02, B64F 1/18 ), in the considered method, at the final section of the flight, an accurate UAV withdrawal to a given area is not required. It is enough to turn off the propulsion system.

This greatly simplifies the entire landing procedure, but requires additional measures to accelerate the finding of UAVs on the ground. In the present invention, it is proposed to apply a radio direction finding procedure to search for an UAV by an operator. For this, before the flight starts, a UAV is installed on its board, for example, in the payload compartment 5, a beacon transmitter with an impact sensor.

The shock sensor works only when the controlled impeller 1 is turned off. The need for this is that in the process of completing a flight mission, an ultralight UAV can experience collisions (for example, with poles, with trees or with a hill surface). Such collisions are not dangerous to the payload of the UAV. Collision shocks are suppressed by the first 2 and second 3 protective hoops, elastic wings 6 and stretch marks 7, as well as additional protective hoops 8, if they are part of the UAV. After the quenching of the impact energy of the drone, the UAV calmly continues the mission. However, in such collisions, the included controlled impeller 1 prohibits the operation of the shock sensor and the inclusion of a beacon transmitter. This is necessary to save energy generated by a special battery (battery) and consumed by the beacon transmitter.

When the controlled impeller 1 is off, the shock sensor is triggered after the UAV hits the earth's surface. In this case, the beacon transmitter is automatically turned on, which begins to periodically send radio signals to the air. The operator charged with the task of finding and evacuating the UAV from the landing area is equipped (Fig. 3) with a portable direction finder - a radio receiver 9 with a direction finder antenna 10 and headphones 11. These devices are similar to the direction finder used in well-known fox hunting competitions. However, the type of direction finder for this invention does not play a significant role.

The radio 9 is tuned to the carrier frequency of the radio signals of the UAV beacon transmitter. When receiving these radio signals (through the antenna 10 of the direction finder), the radio receiver 9 converts them and transmits them to the headphones 11 to generate sound signals. When converting radio signals, the radio 9 takes into account their intensity so that the volume (or repetition frequency) of the signals in the headphones 11 is proportional to the intensity of the radio signal received by the radio 9. That is, the type of signals in the headphones 11 allows the operator to judge the distance to the landing UAV and the accuracy of the direction guidance on the UAV plane of the antenna 10 direction finder. As shown in figure 3, by turning the plane of the antenna 10 direction finder and listening to sound signals in the headphones 11, the operator goes to the radiation source and can quickly find a landed UAV, for example, rolled under a tree.

Thus, the unconventional scheme for constructing an ultralight UAV and the application of the radio direction finding procedure when searching for a landing UAV allow solving the stated problem - to simplify the implementation of the landing procedure as much as possible. Suffice it to say that for the control of UAV flight at the final stage, no other operations are used other than automatic shutdown of the propulsion system, and on the ground no landing and auxiliary means are required, except for the simplest direction finder.

Claims (2)

1. The method of landing an ultralight unmanned aerial vehicle (UAV), in which UAVs are flown horizontally above the earth’s surface, according to a predetermined program or by remote control from the earth, UAVs are brought to the landing area and, after the UAV contacts the earth’s surface, they are evacuated from the landing area, characterized in that before the start of the UAV flight, a beacon transmitter is installed on its board with an impact sensor configured to record the moment of UAV contact with the earth's surface when the engine is off of the installation, after the UAV is brought to the landing area, its propulsion system is turned off and it falls under the influence of gravity, at the moment of the UAV’s contact with the earth’s surface, the beacon transmitter is activated by the signal from the shock sensor, the location of the landing UAV is determined by radio direction finding of the beacon transmitter and its search for subsequent evacuation. 2. The method according to claim 1, characterized in that the direction finding of the UAV beacon transmitter is carried out using equipment similar to the direction finder used in fox hunting competitions.

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