RU2734680C1 - Quadcopter - Google Patents

Abstract

FIELD: aviation.SUBSTANCE: invention relates to aircraft engineering, particularly, to design of unmanned aerial vehicles of vertical take-off and landing. Quadcopter comprises a main panel made of material with high heat conductivity and consisting of two circular parallel plates with a cellular structure arranged between them, and two additional panels, identical in composition, shape and size of main panel. Body is formed by three perpendicularly intersecting said panels rigidly fixed along the line of their intersection, wherein the panels are inscribed in a sphere with a centre at the point of intersection of the central axes of the panels. Between the plates of the main panel there is a bearing frame in the form of a cross-shaped frame, from the ends of which external ends of beams with electric motors and screws come out. When three pairs of plates of panels cross, eight hollow trihedral volumes are formed. Photocells are installed on the outer surface of the plate, which forms the face of the triangular volume, through the electric insulating layer.EFFECT: combination of functions of a receiver-converter of electromagnetic energy of a laser beam into electric power and a passive marker of a search, tracking and guidance system, thermal connection of three panels making up the housing into a single heat network.3 cl, 10 dwg

Description

The invention relates to the field of unmanned aircraft devices using the technology of vertical take-off and landing, intended for scientific research, cargo delivery, aerial photography and video surveillance with the possibility of transmitting information received by onboard sensors to a control station in real time.

Currently, multi-rotor vertical takeoff and landing unmanned aerial vehicles are widely used. The most widespread are models with four rotors - quadrocopters or drones. Quadrocopters are used both for professional purposes - for shooting real estate from the air, aerial photography of a land plot, artistic aerial photography, and in entertainment [Description of drones and their purpose, http://www.abros.ru/opisanie-dronov.html]. Quadrocopters have different purposes depending on the size and programs they have installed. Hence the various options for their use. The largest and most serious models are used in the army - they are equipped with fixed wings and require short airstrips. There are units that are used for geographical surveying of the area, anti-poaching and for meteorological purposes. Smaller quadcopters use vertical take-off and landing technology. And miniature models are launched from the palm of your hand [16 UNIQUE WAYS OF APPLICATION OF QUADROCOPTERS, https://www.moyo.ua/news/16_unikalnyh_sposobov_primeneniya_kvadrokopterov.html]. Professional quadrocopters can reach takeoff weight from several kilograms to tens of kilograms and sizes (excluding propellers) more than 1-1.5 meters. Such dimensions and weight place increased demands on the strength of the quadcopter structure. The most important task in the design of this kind of apparatus is the development of a reliable and durable structure capable of withstanding variable loads, as discussed, for example, in the article [Ermachenkov DI, Fazli TGK, Petrenko EO. Development of a quadrocopter frame design for remote monitoring of objects // Internet magazine, "Naukovedenie" VOL. 8, No. 6 (2016). https://naukovedenie.ru/PDF/45TVN616.pdf]. Some restrictions are imposed on the construction of the quadcopter. In particular, the frame must be of sufficient strength at a relatively low weight.

At the same time, the relatively short flight time of quadrocopters due to the limited capacity of the battery, as a rule, no more than one hour, forces unmanned aerial vehicles (UAVs) to be launched in the immediate vicinity of the task execution area [Folding quadrocopter. Patent for invention No. 2665123, IPC: В64С 27/08 (2006.01). Posted on 28.08.2018, Bul. No. 25].

The size and capacity of batteries is now one of the most problematic factors in the development of unmanned aerial vehicles for vertical take-off and landing. The battery is one of the most important parts of a quadrocopter [Part 3. All about batteries for quadrocopters. http://www.customelectronics.ru/chast-3-vse-ob-akkumulyatorah-dlya-kvadrokopterov/], the motors of which, depending on their size, can consume significant currents. One of the main requirements for batteries is a high current output. And the best characteristics from this point of view are possessed by lithium-polymer batteries. When choosing batteries, consider their capacity, number of cells and maximum discharge current. The capacity (in amperes) directly affects the flight duration, but the larger the capacity, the greater the mass. There are also positive factors - LiPo-batteries have low self-discharge, no memory effect, a large operating temperature range and a small voltage drop during discharge. The disadvantages include not the highest charge density, a small number of operating cycles and fire hazard.

Currently, work is underway to improve the energy and mass characteristics of power supplies for UAVs [The use of air-aluminum chemical power sources on small aircraft with propellers / NS. Okorokova, K.V. Pushkin, S.D. Sevruk et al. // Proceedings of XLII Academic Readings on Cosmonautics. Royal Readings. Moscow 23-26 January 2018 M .: MGTU im. N.E. Bauman, 2018, p. 63], which will allow at least 2 times to increase the energy and mass characteristics and at least 2 times to increase the active flight time in comparison with existing analogues using exclusively lithium-ion (polymer) batteries.

Another way of power supply of aircraft using a wireless power transmission system based on laser installations with a wavelength of 0.5 to 10 microns is also being considered [The moon is a step towards technologies for the development of the solar system / edited by V.P. Legostaev and V.A. Shovels. - M .: RSC Energia, 2011. p. 531-543]. In this case, the electromagnetic energy of the laser beam can be transmitted both from the Earth and from a space or air object [V.I. Kishko, V.F. Matyukhin. Principles of constructing adaptive repeaters for stratospheric energy transmission systems // Avtometriya. 2012. T. 48, No. 2. from. 59-66.]. Laser radiation can be efficiently converted into electricity using photoelectric converters (PECs) based on semiconductor heterostructures placed on transducer receivers made in the form of spatial forms based on cylinders, polyhedrons and their combinations, blades spatially located relative to the aircraft body [G ... Rauschenbach. Handbook for the design of solar panels. M .: Energoatomizdat, 1983, p. 79]. However, the current collection from such receivers varies depending on the angle of incidence of electromagnetic rays, and hence the illumination of individual fragments, the mutual shading of the parts of the receiver-converter structure. In the technical solution [Space receiver-converter of laser radiation. Invention patent No. 2566370, IPC: G01J 5/58 (2006.01). Published on October 27th, 2015. Bul. No. 30], the configuration of an omnidirectional receiver-converter of electromagnetic energy of a laser is considered, which allows directing the laser beam to the receiver-converter from practically any direction and practically removing the dependence of the output electric power of the receiver-converter on the angle of incidence of the laser beam on it. And in the technical solution [Omnidirectional receiver-converter of laser radiation. Patent for invention No. 2630190, IPC: H01L 31/04 (2014.01). Published on 09/05/2017. Bul. No. 25], a passive marker is used in the design of the receiver-transducer, made in the form of an omnidirectional reflector, for laser location of the omnidirectional receiver-transducer, which facilitates the work of the search, tracking and guidance system (PSN) of the laser beam on the aircraft.

There are numerous examples of quadcopter designs and principles of their operation.

So in the material [How does a drone work? https://iot.ru/gadzhety/kak-ustroen-dron] shows the basic components of a quadrocopter, its internal structure and principles of operation. In general, each drone can be divided into the following parts: engines, governors, propellers, flight controller, frame. In particular, the base of a quadcopter is a frame to which all its constituent elements are attached. It should be shockproof, lightweight and durable. The frame is usually made of polymers or tough but lightweight alloys. In addition, carbon, fiberglass and other materials are actively used that can provide maximum structural rigidity. Basically, the frame consists of many parts (less often one-piece), which allows for greater maneuverability and ease of control. It also has holes through which electrical wiring is laid. It connects the flight controller (the "brain" of the drone) to all other parts of the drone. Another important element of the quadcopter is the rechargeable battery. Its capacity (expressed in milliamps per hour) determines the maximum height to which the quadcopter can rise, as well as the range and flight time.

The article [Drone device: an overview for beginners, https://blog.4vision.ru/novichkam/ustrojstvo-drona-obzor-dlja-novichkov.html] discusses the drone design using the example of the DJI Inspire 1 model, power frame, also: propellers - standard and pushing, made of plastic or composite materials; Brushless motors, which are considered to be more efficient in terms of performance and operation than brushed motors; landing gear, which is something like legs mounted under the engines at the ends of the "arms" of the frame; an electronic speed control (ESC) located in the "hands" closer to the engines and representing an electrical circuit that is designed to control the speed of the quadcopter; the flight controller, which acts as a motherboard or even an on-board computer, is responsible for transmitting all the commands that the pilot sends to the aircraft; a receiver responsible for receiving radio signals sent to the quadrocopter through the controller; a transmitter responsible for transmitting radio signals from the controller to the quadrocopter to issue commands for the direction of flight and other related parameters; rechargeable battery, which is one of the main parts of the drone, without which it is impossible to launch the quadcopter and complete all assigned flight tasks.

In the publication [How a drone works - the design of an unmanned vehicle. https://www.yandex.ru/turbo?text=https%3A%2F%2Fzetsila.ru% 2F% 25D0% 25BA% 25D0% 25B0% 25D0% 25BA-] shows a typical drone design and principles of its operation. An unmanned aerial vehicle system contains two pillars: the mechanics of the unmanned aerial vehicle and the control system. The nose of a drone is usually the area of the hull where the navigation system's sensors are installed. The rest of the body is designed to accommodate mechanics, electronics, electrical equipment. The flight system of any drone works thanks to a device called positioning and return home radar. Most modern drones are equipped with two global navigation satellite systems (GNSS). Traditionally, GPS and GLONASS systems are involved in the design of modern drones. When the drone is launched by the user, the machine's system searches and then locates GNSS satellites. The aircraft's radar equipment detects the signal and broadcasts the result on the display of the remote control (RC). In particular, it indicates a low level of the drone's battery on the way back home. Gyroscopic stabilization technology is one of those components that unmanned aerial vehicles "vital" need. The gyroscope is designed for instant processing of loads arising from external forces acting on the structure of the drone. The gyroscope provides the output of the necessary navigation information to the remote control. The flight controller, present in the design of the drone, is in fact a regular computer equipped with the appropriate software. All systems are automatically controlled by such a UAV computer, taking into account the signals received from the user's remote control. In addition, the code of the so-called "firmware" is used as a basic control - a memory microcircuit paired with a microcontroller. The built-in compass function of the remote control system provides the drone with accurate position coordinates during flight. Calibrating the compass sets the return home point - the place where the drone needs to return if the control signal is lost. One of the important items of drone equipment is the first person view (FPV - First Person View). The device of a video camera mounted on an unmanned aerial vehicle and designed to broadcast video in real time to the remote control dispatcher. The FPV function and equipment allows the UAV to fly at significant altitudes and over long distances, limited only by the battery charge. Modern drones are designed with a wide-range wireless FPV transmitter that comes with antennas. Depending on the configuration, the receiver of video signals can be not only a remote control, but also a computer, tablet, smartphone. The UAV remote control module is a device with wireless communication functions. Typically, the 5.8 GHz frequency band is used for communication. During the drone manufacturing process, the remote control system is pre-configured to fully associate with the aircraft. Theoretically, the communication range of the simplest systems is up to 700 m, while professional structures receive a signal stably at a distance of 7 km or more.

Known folding quadrocopter (Patent for invention No. 2665123, IPC: В64С 27/08 (2006.01). Published on 28.08.2018, bull. No. 25), containing a square-shaped body, consisting of two parallel plates, between which the bushings on the axes are installed internal ends four beams - holders of motors with screws, outer ends of beams with electric motors and screws are placed at the corners of a square around the body, and the beams are fastened to the body with the possibility of folding the beams for convenient storage and transportation. This technical solution is the closest in design to the proposed invention and is taken as a prototype.

The common main disadvantage of the above-mentioned quadcopter designs is a short flight time and range, depending on the battery capacity.

So, all quadcopter batteries are relatively heavy, so the structure for mounting them must be strong enough (another reason why the frame should be made of reliable and sturdy materials). Due to the low capacity and small size of the battery, miniature drones can stay in the air for no more than 3-5 minutes. Amateur models are able to stay in the air for about 12-15 minutes. The duration of the flight of professional drones in autonomous mode is no more than half an hour [How does a drone work? https://iot.ru/gadzhety/kak-ustroen-dron].

The objective of the invention is to increase the time, altitude and range of active flight of a quadrocopter.

The technical result of the invention is the combination in the design of the quadcopter, in addition to the functions of an omnidirectional receiver-converter of the electromagnetic energy of a laser beam into electricity and a passive marker of the search, tracking and guidance system (PSN), as well as the functions of a load-bearing structure and thermal, which makes it possible to perform a constructive (power) and thermal linking of three mutually perpendicular honeycomb circular panels that make up its body into a single heating network.

The technical result is achieved by the fact that in the quadcopter, including the body, parallel plates, between which the inner ends of four beams carrying the body are installed, at the outer ends of which there are installed electric motors with screws, placed around the body, the main panel made of material with high thermal conductivity is introduced and consisting of two circular parallel plates with a honeycomb structure placed between them, and two additional panels identical in composition, shape and size of the main panel, subject to the following ratio

where δ is the thickness of the plate;

D is the diameter of the plate;

h is the distance between the inner surfaces of each pair of said plates,

in this case, the body is formed by three perpendicularly intersecting mentioned panels, rigidly fastened along the line of their intersection and inscribed in a sphere of radius R _sp = 0.5 [D ² + (h + 2⋅δ) ² ] ^{l / 2} with the center being the point of intersection of the central the axes of the panels, and between the plates of the main panel there is a supporting frame in the form of a cruciform frame, resulting from its intersection with additional panels, and forming the inner ends of four beams carrying the body, and from the ends of the cruciform frame, the said outer ends of the beams with electric motors go out and screws, while as a result of mutual intersections of three pairs of panel plates, eight hollow triangular volumes are formed, each bounded by three perpendicular faces of a trihedral angle, with a common point - the vertex of the intersection of the faces, where the faces are the plates, and the edges are the intersection lines of the plates, and a triangle on the sphere area S _SF formed at the intersection of the mentioned faces with the surface of the sphere, with m for each panel on the outer surface of the plate, forming the edge of the triangular volume through the electrically insulating layer, photocells are installed to directly convert the energy of the electromagnetic radiation of the laser beam directed to the geometric center of the sphere into electrical energy, and the length L _{1 of the} inner ends of the rays satisfies the expression L ₁ ≤ D / 2, and the length L ₂ . the outer ends of the rays must satisfy the expression:

where L _B is the length of the screw;

H _B - screw height above the outer end of the beam.

In addition, a hollow or solid corner reflector is introduced into the quadcopter, installed in the zone of the triangular angle of each of the eight triangular volumes and made in the form of a regular triangular pyramid, where the lateral faces are reflective and are located on the corresponding faces of the triangular volume, and the base area S _UO is the entrance face of the said reflector and each of them must satisfy the expression S _УO << S _CФ , and structurally separated, but combined functionally into an omnidirectional reflector installed in the central part of three mutually intersecting panels.

And also a cylindrical shell with a height of h _C , where h _C = h, wall thickness Δ and with an outer diameter d, installed along the end surface of each panel, except for the surfaces of mutual intersection of the main panel with additional panels, is introduced into the quadcopter, where Δ = δ and d = D, and the axis of the cylindrical shell coincides with the central axis of the corresponding panel, where the walls of the cylindrical shell are rigidly fastened along the line of their intersection with the corresponding plates and are made of the same material as the plates, and photocells are installed on the outer surface of the cylindrical shell through an electrical insulating layer.

The essence of the invention is illustrated by drawings (Fig. 1-10).

FIG. 1 shows a structural diagram of the main panel 8 made of two circular parallel plates 2, between which a honeycomb structure 9 is placed. To better show the four beams 4 of the cruciform frame 16 installed between the plates 2, carrying the body 1, one of the plates is removed. All the electronic "stuffing" of the quadcopter, placed in the honeycomb structure 9 between the plates 2 of the main panel 8 in FIG. 1 is not shown. FIG. 1 marked: D - the diameter of the main panel 8.

FIG. 2 shows a section A-A of the main panel 8 and two beams 4 carrying the body, each of which contains the inner and outer ends of the beams. FIG. 2 denoted: L ₁ - the length of the inner ends 3 of the rays 4; L ₂ - the length of the outer ends of 5 rays 4.

FIG. 3 shows a detail B of a fragment of the cross-section of the main panel 8 in the area of the bearing frame 15. FIG. 3 indicated: δ - thickness of plate 2; h is the distance between the inner surfaces of the plates 2.

FIG. 4 shows a general view of a quadrocopter with three intersecting panels 8, 10, 11 and an omnidirectional reflector 27 located in its central part. In the main panel 8, the inner ends 3 of four, carrying the body 1, beams 4 are installed, and the outer ends 5 of beams 4 are holders of electric motors 6 with screws 7 are placed around the housing 1. In FIG. 4 indicated: L _B - the length of the screw 7, H _B - the height of the screw 7 above the outer end 5 of the beam 4; R _sf - radius of the sphere 12, the envelope of the panel 8, 10, 11.

FIG. 5 shows a general view of the mutually intersecting plates 2 of panels 8, 10, 11, forming eight hollow trihedral volumes 17. Hatching marks one of the hollow triangular volumes 17, bounded by three perpendicular faces of a trihedral angle, with a common point (vertex) of intersection of the faces, where the faces are plates 2, and ribs 19 - the lines of intersection of plates 2, and a triangle on the sphere 12. In the area of the selected triangular volume 17, a corner reflector (22 hollow or 23 solid) is shown, made in the form of a regular triangular pyramid

FIG. 6 shows a general view of a hollow corner reflector 22 installed in the area of a triangular volume 17, made in the form of a regular triangular pyramid 24, where the side faces 25 are reflective and placed on the corresponding faces of the triangular volume 17, and the base 26 is the entrance face of the corner reflector 22, 23 (fragments of plates 2 of panels 8, 10, 11 are shown with dashed lines).

FIG. 7 shows a general view of a solid corner reflector 23 made of optical material in the form of a regular triangular pyramid 24 with three mutually perpendicular lateral reflective faces 25.

FIG. 8 shows one of the panels 8, 10, 11, including two parallel plates 2, between which a honeycomb structure 9 (without "filling") is placed, and a cylindrical shell 28 is installed along the end surface of the panel 8, 10, 11.

В-В - section of panel 8. On section В-В are shown the remote elements G and D.

FIG. 9 shows a remote element G of a fragment of the arrangement of photocells 29 on a cylindrical shell 28.

FIG. 10 shows a remote element D of a fragment of the arrangement of photocells 29 on the outer surface of the plates 2, forming the faces of the triangular volume 17.

FIG. 1-10, the following designations are adopted:

1 - case;

2 - plate;

3 - inner end of beam 4;

4 - ray;

5 - outer end of beam 4;

6 - electric motor;

7 - screw;

8 - main panel;

9 - honeycomb structure;

10, 11 - additional panel;

12 - sphere;

13 - the center of the sphere 12;

14 - the central axis of the panel 8, 10, 11;

15 - supporting frame of the main panel 8;

16 - cruciform frame of the main panel 8;

17 - triangular volume;

18 - top; 19 rib;

20 - electrical insulating layer;

21 - laser beam;

22 - hollow corner reflector;

23 - solid corner reflector;

24 - pyramid of corner reflector 22, 23;

25 - side face of the corner reflector 22, 23;

26 - the base of the pyramid 24, the entrance face of the corner reflector 22, 23;

27 - omnidirectional reflector;

28 - cylindrical shell;

29 - photocell;

30 - intercell connections of photocells 29;

31 - semiconductor structure of photocell 29;

32 - protective coating of the photocell 29;

33 - face contacts of the photocell 29;

34 - rear contacts of photocell 29;

35 - probe beam.

The quadcopter includes a body 1, parallel plates 2, between which are installed the inner ends 3 of four carrying the body 1, beams 4, at the outer ends 5 of which there are installed electric motors 6 with screws 7, placed around the body 1. The main panel 8 made of material with high thermal conductivity and consisting of two circular parallel plates 2 with a honeycomb structure 9 placed between them, and two additional panels 10, 11, identical in composition, shape and size of the main panel 8, subject to relation (1). In this case, the body 1 is formed by three perpendicularly intersecting mentioned panels 8, 10, 11, rigidly fastened along the line of their intersection, and panels 8, 10, 11 are inscribed in a sphere 12 with a radius of R _sp = 0.5 [D ² + (h + 2⋅ δ) ² ] ^1/2 with a center 13, which is the point of intersection of the central axes 14 of panels 8, 10, 11, and between the plates 2 of the main panel 8 there is a supporting frame 15 in the form of a cruciform frame 16, resulting from its intersection with additional panels 10, 11, and forming the inner ends 3 of the four beams 4 carrying the body 1, and from the ends of the cruciform frame 16 the mentioned outer ends 5 of the beams 4 with the electric motors 6 and screws 7. In this case, as a result of the mutual intersections of three pairs of plates 2 of the panels 8 , 10, 11, eight hollow triangular volumes 17 are formed, each bounded by three perpendicular faces of a trihedral angle, with a common point - the vertex 18 of the intersection of the faces, where the faces are plates 2, and the edges 19 are the lines of intersection of plates 2, and so a rectangle on a sphere 12 with an area S _CF formed at the intersection of the said faces with the surface of the sphere 12, and for each said panel 8, 10, 11 on the outer surface of the plate 2, forming the face of the triangular volume 17 through the electrical insulating layer 20, photocells 29 are installed for direct energy conversion electromagnetic radiation of the laser beam 21 directed to the geometric center 13 of the sphere 12 into electric energy, and the length L _{1 of the} inner ends 3 of the rays 4 satisfies the expression L ₁ ≤D / 2, and the length L _{2 of the} outer ends 5 of the rays 4 must satisfy the expression (2 ). In the area of the triangular corner of each of the eight triangular volumes 17, a hollow 22 or solid 23 corner reflector is installed, made in the form of a regular triangular pyramid 24, where the side faces 25 are reflective and are located on the corresponding faces of the triangular volume 17, and the base 26 with an area S _UO is the entrance face 26 of the said reflector 22, 23 and each of them must satisfy the expression S _UO << S _CF , and structurally separated, but functionally combined into an omnidirectional reflector 27 installed in the central part of three mutually intersecting panels 8, 10, 11. Along the end surface each panel 8, 10, 11, in addition to the surfaces of mutual intersection of the main panel 8 with additional panels 10, 11, a cylindrical shell 28 with a height h _C , where h _C = h, wall thickness Δ, with Δ = δ, and with an outer diameter d , where d = D, and the axis of the cylindrical shell 28 coincides with the central axis 14 of the corresponding panel, where the walls of the cylindrical the shells 28 are rigidly fastened along the line of their intersection with the corresponding plates 2 and are made of the same material as the plates 2 and on the outer surface of the cylindrical shell 28 through the electrical insulating layer 20, the above-mentioned photocells 29 are installed. Intercell connections 30 provide electrical connections of individual photocells 29, where there is a direct conversion of the energy of the laser beam 21 in the semiconductor structure 31, with a protective coating 32, into a photoelectric current, which is removed using the face contact 33 and the back contact 34. Moreover, a passive marker made in the form of an omnidirectional reflector is installed in the structure of the housing 1 for laser ranging 27, on which the probe beam 35 falls.

Thus, the body 1 of the quadcopter is made in the form of an omnidirectional receiver-converter, which is panels 8, 10, 11 with photocells 29 installed, as indicated above.

The quadcopter works as follows.

Let us put electromagnetic radiation from a laser radiation generation system (LSS) (not shown in the figures), located at a ground, air or space control station (not shown in the figures), by a formation and guidance system (SFIN) (not shown in the figures), is formed in the laser beam 21 with the specified parameters and using the search, tracking and guidance system (PSN) (not shown in the figures), is directed to the body 1 of the quadcopter, made in the form of an omnidirectional receiver-converter of three perpendicularly intersecting panels 8, 10, 11 (Fig. . 4). The PSN system directs the axis of the laser beam 21 to the center 13, which is the point of intersection of the central axes 14 of the panels 8, 10, 11, inscribed in the sphere 12 with radius R _sp = 0.5 [D ² + (h + 2⋅δ) ² ] ^{1 / 2} (Fig. 4), and the laser beam 21 is directed to the housing 1, regardless of its position.

For a passive quadcopter, an initial search for a signal from a response optical device installed on an omnidirectional receiver-transducer is implemented, made in the form of an omnidirectional 1 reflector 27 based on hollow corner reflectors 22 or solid corner reflectors 23. Namely, a part of the electromagnetic energy of the laser beam 21, called the probe beam 35, falls on an omnidirectional reflector 27 and reverses the direction of its propagation. Thus, the energy is reflected; of the beam in the form of a signal enters the receiver of the PSN system of the control station, which allows for a long time with high accuracy to maintain the tracking and guidance mode in the closed-loop loop of the PSN system.

Monochromatic electromagnetic radiation of the laser beam 21 falls on the edges of hollow triangular volumes 17 formed as a result of mutual intersections of plates 2 of panels 8, 10, 11, each bounded by three perpendicular faces of a triangular angle, with a common point (vertex) 18 of intersection of faces, where the faces are plates 2, and the edges 19 - the lines of intersection of the plates 2, and a triangle on the sphere 12 with area S _SF , formed at the intersection of the said faces with the surface of the sphere 12 (Fig. 5, 1-3). On these edges, through the electrical insulating layer 20, photoelectric converters based on semiconductor photocells 29 are installed (Fig. 10). Simultaneously, the monochromatic electromagnetic radiation of the laser beam 21 falls on the cylindrical shells 28, which are installed on the end surface of each panel 8, 10, 11 (Fig. 8, 5), except for the surfaces of mutual intersection of the main panel 8 with additional panels 10, 11, and made height h _C , where h _C = h, wall thickness Δ, where Δ = δ, and with an outer diameter d, where d = D, and the axis of the cylindrical shell 28 coincides with the central axis 14 of the corresponding circular panel, where the walls of the cylindrical shell 35 are rigid fastened along the line of their intersection with the corresponding plates 2, which gives additional strength to the structure of the body 1, and are made of the same material as the plates 2, where, as well as on the edges of the triangular volumes 17, on the outer surface of the cylindrical shell 28 through the electrically insulating layer 20 installed photoelectric converters based on semiconductor photocells 29 (Fig. 9). Further, the electromagnetic radiation incident on the above-mentioned photoelectric converters passes through the transparent protective coating 32 into the photoactive region of the semiconductor structure 31 of the photocells 29 (Figs. 9, 10) with intercell connections 30. The process of active absorption of photons with a maximum absorption coefficient of electromagnetic radiation takes place due to appropriate selection of the semiconductor material of photocells 29 for a given wavelength λ, monochromatic laser radiation, as discussed, for example, in the technical solution [RF Patent No. 2487438, IPC: H01L 31/042 (2006.01), publ. 10.07.2013, Bul. No. 19] or [RF Patent No. 2593821, IPC: H01L 31/04 (2014.01), publ. 08/10/2016, Bul. No. 22]. Thus, in the photocells 29 there is a direct conversion of the energy of electromagnetic radiation, based on the photovoltaic effect, into a photovoltaic current, which is removed by means of the face contact 33 and the back contact 34. Intercell connections 30 provide electrical connections of individual photocells 29 in parallel and series circuits to obtain the required parameters of direct current generated by an omnidirectional receiver-converter, which is the power supply of the quadcopter. And then, through a conversion device (not shown in the figures), as, for example, shown in [Drone device: an overview for beginners. https://blog.4vision.ru/novichkam/ustrojstvo-drona-obzor-dlja-novichkov.html], using an electronic speed controller (ESC) (not shown in the figures), designed to control the speed of the drone, the direct current of the source is converted power supply in alternating current, which is needed by the electric motors 6, which drive the screws 7.

In active flight, the quadcopter structure, made in the form of the main panel 8 (Figs. 1-3) and two additional panels 10, 11 crossing it perpendicularly, rigidly fastened along the line of their intersection, with a diameter D and each including two parallel plates 2, thickness δ and with a distance h between their inner surfaces and surfaces satisfying expression (1), it experiences loads arising from external forces. Basically, these loads are experienced by the supporting frame 15 of the main panel 8, made in the form of a cruciform frame 16, resulting from its intersection with additional panels 10, 11 and forming the inner ends 3 of four beams 4 carrying the body 1, and from the ends of the cruciform frame 16 the outer ends 5 of beams 4 come out with electric motors 6 and screws 7, placed around the body 1. Moreover, the length L _{1 of the} inner ends of 3 beams 4 satisfies the expression L ₁ ≤D / 2, and the length L _{2 of the} outer ends 7 of beams 4 must satisfy the expression (2 ).

Part of the load acting on the main panel 8 is transferred to the plates 2 of the two additional panels 10, 11, acting as stiffeners, and thus, unloading the supporting frame 15, made in the form of a cruciform frame 16.

During the flight operation of the quadrocopter, simultaneously with the conversion of the electromagnetic energy of the laser beam 21 into electricity, there is also the process of heat exchange in the structural elements of the omnidirectional receiver-converter, which forms the body 1 of three perpendicularly intersecting panels 8, 10, 11.

One part of the energy of the laser beam 21, not converted into electricity in the omnidirectional receiver-converter, by heat transfer from the front surface of the photocells 29, goes into the air space surrounding the body 1 of the quadcopter.

Another part of the unconverted energy, due to the incomplete use of the flux of electromagnetic radiation of the laser beam 21 falling on the photocells 29 in the semiconductor structure 31, in the form of thermal energy through the back contact 34 and the electrically insulating layer 20 enters the outer surface of the plate 2 and then to the parallel plate, due to the high thermal conductivity of the plates 2 and the honeycomb structure 9 located between them. Due to the rigid structural connections between the panels 8, 10, 11, as well as between them and the cylindrical shell 28, with the high thermal conductivity of these structural elements, the unconverted heat is effectively dissipated over the surfaces of the plates 2 of each panels 8, 10, 11. Thus, heat is transferred to the shaded surfaces of the housing 1 from the surfaces on which the electromagnetic energy of the laser beam 21 falls. As a result, a more uniform temperature distribution over the plates 2 is provided, which contributes to a more effect eve heat exchange with the environment. On the other hand, more equal temperature conditions of operation of photocells 29 increase the reliability of operation of the omnidirectional receiver-converter as a whole. In addition, the uniform temperature distribution in the thin-walled elements that make up the structure of the quadcopter body 1 reduces local thermal stresses caused by the fall of the concentrated electromagnetic energy of the laser beam 21 on individual structural elements, which increases the efficiency of the quadrocopter as an aircraft.

At the same time, as noted above, a part of the electromagnetic energy of the laser beam 21 is used as the probe beam 35 of the laser locating system (LLS). The electromagnetic energy of the probing beam 35 falls on the hollow corner reflectors 22 or solid corner reflectors 23 installed in the area of the triangular angle of each of the eight triangular volumes 17 and made in the form of a regular triangular pyramid 24, where the lateral faces 25 are reflective and placed on the corresponding faces of the triangular angle trihedral volume 17, and the base area 26 S _RO is input facet 26 of corner reflectors 22, 23 and each of them has to satisfy the expression S _RO << S _CF. Moreover, they are structurally separated, but functionally combined into an omnidirectional reflector 27, installed in the central part of three mutually intersecting panels 8, 10, 11. Moreover, depending on the relative position of panels 8, 10, 11 relative to the direction of the probing beam 35, the visible for the probing beam will change 35 is the frontal surface area of the omnidirectional reflector 27. As seen in FIG. 4 and 5, depending on the direction of the axis of the probing beam 35, relative to the position of the intersecting panels 8, 10, 11, illumination from one to four entrance faces 26 of the omnidirectional reflector 27 is possible. For example, when the axis of the probing beam 35 coincides with the bisector of the triangular angle triangular volume 17, only the entrance edge 26 of one corner reflector will be illuminated - hollow corner reflectors 22 or solid corner reflectors 23, and when the axis of the probing beam 35 coincides with the central axis 14 (Fig. 4), one of the panels 8, 10, 11 will be illuminated four entrance edges 26 for four corner reflectors - hollow corner reflectors 22 or solid corner reflectors 23. In this case, taking into account the shading of the entrance edges 26 by panels 8, 10, 11, intermediate situations are possible.

In the case of an omnidirectional reflector 27 of eight hollow corner reflectors 22 (Fig. 6), the photons of the probe beam 35 pass through the entrance face 26, generally from one to four hollow corner reflectors 22, and fall on the reflecting side faces 25 of the pyramid 24, made mirrored. Specular reflection from each of the three reflecting side faces 25 leads to a flip corresponding to the component of the photon velocity vector in the direction strictly opposite to the initial one, i.e. in the direction of the receiver of the PSN system.

In the case of an omnidirectional reflector 27, consisting of eight solid corner reflectors 23 (Fig. 7) made of optical material, photons of the probing beam 35 fall on the entrance face 26 (in the general case, on the entrance faces 26 from one to four solid corner reflectors 23) , as a rule, with an antireflection coating film applied to its surface (not shown in the figures), where they refract (first refraction) and pass from an optically less dense medium (air) to an optically denser one (antireflection coating). Further, at the boundary of two media (antireflection coating optical material), the laser beam of the probe beam 35 undergoes a second refraction, and then electromagnetic waves pass through the optical material and fall on the reflecting side faces 25, which leads to a flip of the corresponding component of the photon velocity vector in the direction strictly opposite to the initial one. Further, the laser beam, undergoing two refractions in the opposite direction, as discussed above, leaves the solid corner reflector 23 at the same angle at which it previously fell on the entrance face 26, in the direction of the receiver of the PSN system.

Let's give a calculated example of a quadcopter design.

The body 1 of the quadcopter is formed in the form of a main panel 8, consisting of two circular parallel plates 2 with a diameter D and a thickness of 5 with a honeycomb structure 9 placed between them, and two additional panels 10, 11, identical in composition, shape and size to the main panel 8. Three the perpendicularly intersecting said panels 8, 10, 11, rigidly fastened along the line of their intersection, are inscribed in a sphere 12 with center 13, which is the point of intersection of the central axes 14 of panels 8, 10, 11. Mutually intersecting panels 8, 10, 11, with cylindrical shells 28, form a housing 1 in the form of an omnidirectional receiver-converter of laser radiation into electricity, and where photocells 29 are installed on the receiving surfaces of the housing 1.

For this example, we will take a circular laser beam 21, i.e. the spatial distribution of the power of the laser beam 21 has circular symmetry. The axis of the laser beam 21 is directed to the center 13 of the sphere 12. In this case, coherent electromagnetic waves of the optical range are emitted, we put the length λ = 0.8 μm [Physical encyclopedic dictionary. Moscow, "Soviet Encyclopedia", 1983. S. 338]. Let us assume that the laser beam 21 falls on the housing 1, i.e. on the receiving surface of the receiver-converter, continuously with an average power density E = 18⋅10 ³ W / m ² , referred to the cross section of the laser beam 21 with a diameter approximately equal to the diameter D of panels 8, 10, 11. In the first approximation, we take the dependence of the relative output electrical power (P / P ₀ ) taken from the receiver-converter, from the direction of the axis of the laser beam 21 incident on the receiver-converter, similar to the P / P ₀ dependence for a spherical solar battery, as the closest geometry, and given in [ G. Rauschenbach. Handbook for the design of solar panels. M .: Energoatomizdat, 1983. S. 79], where P / P ₀ = 0.9-1.0. Here P ₀ is the maximum output electrical power taken from the omnidirectional receiver-converter. Using the equation from [G. Rauschenbach. Handbook for the design of solar panels. M: Energoatomizdat, 1983. S. 73], we write in general form for the output electric power of the omnidirectional receiver-converter the ratio

where E is the average power density of the laser beam 21 incident on the receiver-converter, W / m ² ;

η - conversion efficiency of the receiver-converter, rel. units;

F is a total factor that takes into account the possible degradation of its parameters and the characteristics of the receiver-converter, including a decrease in the useful area of the panel 8, 10, 11 due to the use of an omnidirectional reflector 27 used by the PSN system;

i - panel number 8, 10, 11;

(S _PP ) _i - the area of the receiving surface of the i-th panel 8, 10, 11, on which the laser beam 21 falls;

Г _i is the angle between the axis of the laser beam 21 and the normal to the plane of the i-th panel 8, 10, 11.

In the receiver-converter under consideration, the receiving surface area Snn is formed by the faces (or parts of the faces) of the triangular volume 17 and part of the area of the cylindrical shell 28 of the panel 8, 10, 11, since the laser beam 21 falls, as a rule, on a part of the area of the plates 2 of the triangular volume 17, and the other part of this plate 2 is obscured (shaded) by adjacent panels 8, 10, 11 and therefore remains in the shadow.

Basic materials for the production of photocells 29 with an internal photoelectric effect [V.S. Avduevsky, G.R. Uspensky. Space industry. Moscow. Mechanical engineering, 1989, S. 138] are semiconductor structures 31 based on compounds of elements III and V (A ^III B ^V ), II and VI groups (A ^II B ^VI ) or based on semiconductors of group IV of the periodic table of elements. For a computational example, as photocells 29, covering through the electrical insulating layer 20 the outer surfaces of the cylindrical shell 28 and plate 2, forming the faces of the triangular volumes 17, panels 8, 10, 11, we use thin-film single-junction photovoltaic cells (PVCs) based on AlGaAs / GaAs [Zh .AND. Alferov, V.M. Andreev, V.D. Rumyantsev. Trends and prospects for the development of solar photoenergy // Physics and technology of semiconductors, 2004, volume 38, no. 8, p. 937-948], developed at the Physico-Technical Institute. A.F. Ioffe RAS and allowing to maintain high efficiency while reducing the thickness of the PVC structure to less than 10 microns [V.I. Kishko, V.F. Matyukhin. Principles of constructing adaptive repeaters for stratospheric energy transmission systems // Avtometriya. 2012. T. 48, no. 2. from. 59-66.]. The GaAs-based material selected as the semiconductor structure 31 has the highest absorption rate for the laser wavelength λ = 0.8 μm selected in the calculation example, in comparison with other semiconductors [V.A. Griliches, P.P. Orlov, L.B. Popov. Solar energy and space travel. Moscow: Nauka, 1984, p. 93]. The protective coating 32 of the photocells 29 is assumed to be made of ZnS, as suggested, for example, in the technical solution [Photocell of the laser receiver-converter. Invention patent No. 2593821, IPC: H01L 31/04 (2014.01). Published on August 10th, 2016. Bul. No. 22]. For each panel 8, 10, 11, through the electrical insulating layer 20, we install photocells 29 with strip front contacts 33 and solid rear contacts 34 made of Au-based material and switch them into series-parallel circuits. In the computational example, we take the efficiency of photocells 29 with an internal photoelectric effect η = 0.5, and the total factor, taking into account switching losses and additional thermal load on the omnidirectional receiver-converter, tested by housing 1 from solar radiation, in the first approximation we take F = 0.9 ... We assume that the maximum output electrical power (P ₀ ) taken from the omnidirectional receiver-converter corresponds to the direction of the laser beam axis coinciding with the central axis 14 of any panel 8, 10, 11. In this example, we will take the value of the maximum output electric power of the omnidirectional receiver-converter P ₀ = 4⋅10 ³ W. Solving equation (3) with respect to S _PP, we obtain the area of the receiving plane, in this case it practically coincides with the area of the panel (S), on one side, i.e.

S _PP = P ₀ / (E⋅cosG⋅η F) = 4⋅10 ³ / (18⋅10 ³ ⋅cos 0⋅0.5⋅0.9) = 0.5 m ² .

From where we determine the dimensions of the receiver-converter, i.e. diameter of plates of 2 panels 8, 10, 11 D = 2⋅ (S / π) ^0.5 = 2⋅ (0.5 / π) ^{0 5} ≈ 0.8 m = 800 mm. Each panel 8, 10, 11 includes two parallel plates 2, 5 thick (we take 8 = 1 mm) and with a distance h (we take h = 80 mm) between their inner surfaces, which satisfies the condition δ << h << D. Thus, the body 1 of the quadcopter is made as lightweight as possible from thin-walled shells, which is typical for aircraft. Moreover, the plates 2 and the honeycomb structure 9 (Fig. 8) are made of a material with high thermal conductivity, for which we choose aluminum or alloys based on it, since this metal has sufficient strength, low specific gravity and high thermal conductivity [Physical quantities. Handbook ed. I.S. Grigorieva, E.Z. Meilikhova. M .: Energoatomizdat, 1991. p. 52-56, 99, 340], which is very important when designing an omnidirectional receiver-converter of the energy of the laser beam 21 into electric power for a quadcopter. We execute each panel 8, 10, 11 in the form of a honeycomb structure 9 of aluminum foil with a thickness of δ _f = 0.1 mm (Fig. 1, 8). Moreover, panels 8, 10, 11 are placed so that they are inscribed in a sphere 12 with a radius of R _sp = 0.5 [D ² + (h + 2⋅δ) ² ] ^{1, / 2} = 0.5 [64⋅10 ⁴ + (80 + 2⋅0.1) ² ] ^{1, / 2} = 4.02⋅10 ² mm with center 13, which is the point of intersection of the central axes 14 of panels 8, 10, 11. The entire electronic "filling" (in the figure not shown) the quadcopter is placed in the honeycomb structure 9 between the plates 2 of the main panel 8. Between the plates 2 of the main panel 8, we also place the supporting frame 15 in the form of a cruciform frame 16, resulting from its intersection with additional panels 10, 11, and forming the inner ends 3 of four carrying the body 1 beams 4, and from the ends of the cruciform frame 16 emerge the outer ends 5 of the beams 4 with electric motors 6 and screws 7, placed around the body 1, as shown in Fig. 1-4. Moreover, the length L _{1 of the} inner ends 3 of the rays 4 is taken equal to L ₁ = 400 mm, which satisfies the expression L ₁ ≤D / 2. We take the length of the screw 7 L _B = 300 mm, the height of the screw 7 above the outer end 5 of the beam 4 H _B = 150 mm, and the length of the outer ends of the 5 beams 4 we take L ₂ = 150 mm, which satisfies expression (2), i.e.

L ₂ > L _B / 2-D / 2 + {0.25⋅D ² - [H _B - (h / 2 + δ)] ² } ^1/2 = 300 / 2-800 / 2 + {0.25 ⋅64⋅10 ⁴ - [150- (80/2 + 1)] ² } ^1/2 = 130 mm.

In the area of the triangular corner of each of the eight triangular volumes 17, a hollow corner reflector 22 or a solid corner reflector 23 is installed, made in the form of a regular triangular pyramid 24, where the lateral faces 25 are reflective and are placed on the corresponding faces of the triangular volume 17. Let us take the value of the side edge b of the pyramid 24 equal to b = 30 mm, whence we determine the area S _{UO of the} base 26 of the pyramid 24, which is the entrance face 26 of the hollow corner reflector 22 or the solid corner reflector 23, according to the formula [IN Bronstein, KA Semendyaev. A guide to mathematics for engineers and students of technical colleges. Ed. recycled. Edited by G. Grosche and W. Ziegler. Joint publication. Publishing House "Teubner" Leipzig, Moscow "Science", Ch. ed. physical-mat. lit., 1981. p. 217]. Whence S _UO = b ² ⋅sin60 ° / 2 = 30 ² ⋅sin60 ° / 2 = 3.9⋅10 ² mm ² = 3.9⋅10 ^-4 m ² . For comparison, let us determine the area S _{SF of the} triangle on the sphere 12 of one of the eight hollow triangular volumes 17, knowing the area of the sphere 12 S and the area of the spherical surface of the three spherical layers ∑S _SL formed at the intersection of the plates 2 of panels 8, 10, 11 with the sphere 12, according to dependencies given in [IN Bronstein, KA Semendyaev. A guide to mathematics for engineers and students of technical colleges. Ed. recycled. Edited by G. Grosche and W. Ziegler. Joint publication. Publishing House "Teubner" Leipzig, Moscow "Science", Ch. ed. physical-mat. lit., 1981. p. 224], according to the formula

Thus, comparing the obtained values of the areas S _UO and S _SF , it can be seen that the area of the input face 26 of the hollow corner reflector 22 or the solid corner reflector 23 is 0.134% of the area S _{SF of the} triangle on the sphere 12 of the hollow triangular volume 17, which satisfies the required condition S _UO << S _SF .

Let us assume that the axis of the probing beam 35 coincides with the bisector of the trihedral angle of the triangular volume 17, i.e. only the entrance face 26 of one corner reflector will be illuminated - a hollow corner reflector 22 or a solid corner reflector 23. From where, in the first approximation, we determine the power of the probing beam 35 incident on the omnidirectional reflector 27, according to the expression W = Е⋅S _УО = 18⋅10 ³ ⋅3.9⋅10 ^-4 = 7 W. For this example, we make an omnidirectional reflector 27 consisting of eight hollow corner reflectors 22. Moreover, the lateral faces 25 are mirrored with a reflective silver coating, which is primarily caused by the highest spectral reflectance ρ _{λ of} silver films. For the wavelength λ = 0.8 μm adopted in the example, the reflection coefficient of the silver film, which we use as a coating, ρ _λ = 0.964 [Physical quantities. Handbook ed. I.S. Grigorieva, E.Z. Meilikhova. Moscow: Energoatomizdat, 1991. S. 783].

The derivation of relation (2) follows from consideration of the geometry of the quadrocopter elements shown in Fig. 1, 2, 4, is quite obvious and is determined by the inadmissibility of the screws 7 touching panels 8, 10, 11 in flight.

In addition, we note the positive aspects of the proposed quadcopter design:

- design versatility - the body consists of three panels of the same design, made of material with high thermal conductivity and each consisting of two circular parallel plates with a honeycomb structure placed between them;

- additional panels actually perform several functions: they develop the surface for placing the FEP, form an omnidirectional receiver-converter, provide the rigidity of the main panel and four beams carrying the body;

- the end surfaces of the panels were used, introducing into the design cylindrical shells, on which the FEPs are additionally placed and which give the entire structure of the quadcopter additional rigidity;

- unlike aircraft that use solar converters in their design, the proposed design can fly both during the day and at night;

- the highly heat-conductive honeycomb design of the panels allows you to effectively redistribute heat between the plates of each panel, which leads to the equalization of the temperature of the quadcopter body;

- the structure is made on the basis of thin-walled shells, this allows obtaining the minimum specific mass of the structure, which is a necessary condition for aircraft operating in airspace;

- effectively use the proposed design of a quadcopter, where they do not require high flight speeds, but require long hovering times over the object of study.

Claims (6)

1. A quadrocopter, including a body, parallel plates, between which the inner ends of four beams carrying the body are installed, at the outer ends of which there are installed electric motors with screws, placed around the body, characterized in that the main panel made of a material with high thermal conductivity is introduced into it and consisting of two round parallel plates with a honeycomb structure placed between them, and two additional panels, identical in composition, shape and size of the main panel, subject to the following ratio δ << h << D, where δ is the thickness of the plate; D is the diameter of the plate; h is the distance between the inner surfaces of each pair of said plates, while the body is formed by three perpendicularly intersecting said panels, rigidly fastened along the line of their intersection, and the panels are inscribed in a sphere of radius R _cf = 0.5 [D ² + (h + 2⋅δ ) ² ] ^1/2 with the center, which is the point of intersection of the central axes of the panels, and between the plates of the main panel there is a supporting frame in the form of a cruciform frame, resulting from its intersection with additional panels and forming the inner ends of four beams carrying the body, and from the ends of the cruciform the above-mentioned outer ends of the beams come out with electric motors and screws, while as a result of mutual intersections of three pairs of panel plates, eight hollow triangular volumes are formed, each bounded by three perpendicular faces of a trihedral angle, with a common point - the vertex of the intersection of the faces, where the faces are the plates, and the edges - the lines of intersection of the plates, and a triangle on the sphere is flat spade S _SF , formed at the intersection of the said edges with the surface of the sphere, and for each of the said panel on the outer surface of the plate, forming the edge of the triangular volume, through an electrically insulating layer, photocells are installed to directly convert the energy of electromagnetic radiation of a laser beam directed to the geometric center of the sphere into an electric one energy, and the length L _{1 of the} inner ends of the beams satisfies the expression L ₁ ≤D / 2, and the length L _{2 of the} outer ends of the beams must satisfy the expression: L ₂ > L _B / 2-D / 2 + {0.25 D ² - [H _B - (h / 2 + δ)] ² } ^1/2 , where L _B is the length of the screw; Н _B is the screw height above the outer end of the beam. 2. The quadcopter according to claim 1, characterized in that a hollow or solid corner reflector is introduced into it, installed in the zone of the triangular angle of each of the eight triangular volumes and made in the form of a regular triangular pyramid, where the lateral faces are reflective and are placed on the corresponding faces of the triangular volume, and the base with area S _YO is the entrance face of the said reflector and each of them must satisfy the expression S _UO << S _CФ , and structurally separated, but combined functionally into an omnidirectional reflector installed in the central part of three mutually intersecting panels. 3. The quadrocopter according to claim 1, characterized in that a cylindrical shell of height h _C is introduced into it, where h _C = h, wall thickness Δ and with an outer diameter d, installed on the end surface of each panel, except for the surfaces of mutual intersection of the main panel with additional panels, with Δ = δ and d = D, and the axis of the cylindrical shell coincides with the central axis of the corresponding panel, where the walls of the cylindrical shell are rigidly fastened along the line of their intersection with the corresponding plates and are made of the same material as the plates, and on the outer the surface of the cylindrical shell through an electrically insulating layer, photocells are installed.

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