BG112876A - System for automatic vertical landing guidance of unmanned aerial vehicles - Google Patents

Abstract

The system for automatic guidance of unmanned aerial vehicles in vertical landing, according to the invention, is intended for the use of a landing pad with significantly smaller dimensions than the absolute error of the coordinates obtained from the civil GPS system. The system is applicable for stationary and mobile sites, with a mounted landing pad. It consists of stations on the sending and receiving side, a flight control unit, an on-board information module, a guidance module and a landing pad with an optical curtain above it. Initially, the flight is directed along the coordinates of the civil GPS system until it reaches near the pad, from where there is close communication with the station of the host side. Afterwards the guidance begins towards the landing pad, above which is formed an optical curtain via laser diodes, the beams of which are modulated separately and with a common identification number of the pad. Each of the beams directs the drone in the direction of the central beam located in the center of the site. After positioning above it, the landing on the pad begins, as it is controlled by an altimeter.

Description

VERTICAL AUTOMATIC DIRECTION SYSTEM FOR VERTICAL AIRCRAFT

LANDING

I. Field of technology

The invention relates to a system of intelligent technical means by means of which an unmanned aerial vehicle (UAV) can be directed and controlled automatically for landing on a stationary or moving landing site, the dimensions of which are significantly smaller than the area in which it can be guided by the coordinates of the civil GPS system.

II. BACKGROUND OF THE INVENTION

An automatic take-off and landing system [1] is known, through which it is possible for the flying object to take off and land without the intervention of an operator.

The invention provides an automated take-off and landing system comprising a flying object (drone) and a take-off and landing site, wherein the flying object has on board a video camera mounted to operate downstream of the flying object, navigation means for moving the drone and an image control and processing unit acquired by the imaging device and the navigation means control, where the control unit calculates the positional relationship between the take-off and landing site and the flying object based on the captured image of the site acquired by the capture device of images, and controls the take-off and landing operations of the flying object based on the result of the calculation.

According to the block diagram of the system, there is a flight control unit on board the UAV, which is controlled by a control microcontroller.

A GPS receiver, an electric motor control unit, a wireless interface for long-distance communication with the base stations, a wireless interface for close communication with the drone and an altimeter are connected to it. According to the described operation of the system, the flight and landing are controlled by base stations on both sides, built by a main computer, to which information is connected wireless interface for long-distance communication with UAVs, GPS receiver, interface for long-distance communication between the two base stations and wireless interface for close communication between the base station of the receiving country with the UAV.

An automatic take-off and landing system is known [2], through which it is possible for the flying object to take off and land without operator intervention.

The take-off and landing targeting system used in the automated take-off and landing system, including an airfield, contains as many light-emitting elements as needed to display or display pre-stored templates / figures / and a control unit for control of radiation from light-emitting elements on the site. The light emitting elements are provided on the take-off and landing site and are arranged in such a way that a circle-shaped marking is formed with the center of the model with all lights on during landing. Different models / states / shaping figures that guide the flying object during landing are stored. There are also models that algorithmically transmit code to the drone to recognize if this is the correct site.

III. Technical essence of the invention

The objective of the invention is to provide a system for automatic guidance of unmanned aerial vehicles in vertical landing, whose flight is initially directed to the coordinates of the civil GPS system, and after reaching near the site, the system takes over the guidance autonomously. This makes it possible to use a landing site with significantly smaller dimensions than the absolute error of the coordinates obtained from the civil GPS system. The system is applicable for stationary and mobile sites, with installed and equipped landing site.

In FIG. 1 shows a situation in which a UAV comes from the east. If this direction is not suitable for a specific site, the directions can be reoriented and accordingly set in the flight plan of the UAV.

There are two parties involved in the UAV service system - "Sending" and "Receiving". The consignor shall have a station of the sending Party (SIS) through which it communicates with the aircraft for its control via a wireless long-distance communication interface (WIDC) and a long-distance communication interface (IDC) communicating with the station of the receiving country. flight logistics management. SPS, in turn, through a wireless interface for close communication (BIBK) communicates with the aircraft for its direction to the landing site (PC). Usually both stations have to perform both functions of sending and receiving and in that case they must have compliance in their equipment (presence of BIBK and BIDK in both stations and corresponding landing sites).

The stations have a main computer (GC) connected to BIDK (GSM, RF or other), BIBK (Wi-Fi, Lora, RF, etc.) and a long-distance communication interface (IDC) between SIS and SPS, which can be wired or wireless (Internet, GSM or other).

On board the UAV there is a flight control unit (BUP), containing a control microcontroller (UMK), GPS receiver (GPS) for determining the coordinates, control unit for electric motors (BUED), BIBK, BIDK and altimeter (VM) . It is possible that there are other blocks related to the performance of other functions and tasks.

An information and additional on-board information module (BIM) is connected to the UMP of BUP through its information microcontroller (IMC). The information in it comes from a photodetector (FP), directed downwards, through an amplifier-limiter (MA), and the processed information enters the UMK.

In the Host Party there is a guidance module (NM), which has the task to direct the UAV to the center of the PC. It contains a directing microcontroller (NMC), which is connected to the GC of the ATP and controls through modulating drivers (MD) the seven laser diodes (LD) mounted on the PC in a certain configuration. The PC in the host country can be placed on the ground, on a roof, or on an open terrace, but with a very precise geographical positioning and orientation (for example north-south). Around it in the four corners are mounted LD (angle lasers), directed upwards. Another laser LD (central) is installed right in the middle of the site. Its light in a narrow beam is directed straight up. Thus, the beam of the central laser falls in the area between the four beams of the angular lasers. From a certain height upwards, the radiation patterns of the angular lasers overlap at their periphery.

In addition, one additional laser is mounted on two opposite sides of the site. The straight line connecting the centers of the auxiliary lasers passes through the center of the central laser and intersects perpendicularly to the middle of both sides of the site. Their directivity diagrams partially overlap with the angular lasers located on the respective side of the site.

If necessary, the curtain can be expanded with two additional lasers (for example, if the PC is on a mobile object). This creates a dense optical curtain (03) in the area where the arriving drone is expected to hit, taking into account the allowable error of its GPS receiver. Initially, the UAV is directed to a defined point from which it can carry out close communication with the Host Party, ie to fall into a virtual area for close communication (CLS) between the UAV and the ATP of the Host Party. The area should be ·· · · · ·· ♦ ··· ··· ·· away from the site and from it to start approaching the UAV for landing. The specified horizontal (Χ, Υ) coordinates for this area determine the center of a circle having a radius equal to the greater maximum absolute error of one of these coordinates (ΔΧ or ΔΥ). Taking into account the error along the vertical axis Ζ, a figure of a cylinder with a height twice as high as the maximum absolute error along the vertical Δ Ζ is obtained. In the flight plan of the UAV, the center of the cylinder is set as the coordinate, and its volume determines the possible place where the drone may arrive due to the errors of its GPS receiver.

All laser beam patterns form a solid 03 with dimensions. This ensures that even at the maximum absolute error of the GPS receiver, moving in the direction of the site, the UAV will cross it, because the width of the ZOBK is greater than twice the error (2.ΔΧ) of the GPS receiver.

When the PC is mounted on a moving object (motor vehicle, vessel, train or other), it is necessary to have a GPS receiver in SPS2, which receives the current GPS coordinates of the moving object and continuously sends the current coordinates of ZOBK to the UAV.

In many cases, the UAV takes off and lands to perform a specific task and must return to the same site. In these cases, it appears as the Host Party and must be equipped with the appropriate NM and laser configuration around it.

Advantages of the invention are that in addition to the BIBC, the system provides a very high speed for data exchange through the beams of LD and FP, which is a prerequisite for a more reliable landing. In addition, relatively simpler and shorter control algorithms are needed, which is realized with microcontrollers with smaller computing capacity and, accordingly, with lower consumption on board the UAV. The system can also work in case of a defect in some of the lasers and easily overcome strong interference that penetrates it.

IV. Description of the attached figure

The patent is explained in more detail with the help of the exemplary embodiment of a system for automatic guidance of unmanned aerial vehicles in vertical landing, presented in the figure with its block diagram (Fig. 1):

• SIS 1 is a station of the sending country, which is located at the Sender of the UAV. It contains a main computer GK 3, wireless interface for remote communication BIDK 4 (GSM, RF or other), GPS-receiver GPS 5, interface for remote communication IDK 6 (Internet, GSM, RF or other) and wireless interface for close communication BIBK 7 (Wi-Fi, Lora, RF or other);

• SPS 2 is a station of the receiving country, which is located at the Receiving UAV. It contains a main computer GK 8, wireless interface for remote communication BIDK 9 (GSM, RF or other), GPS-receiver GPS 10, interface for remote communication IDK 11 by cable or wireless (Internet, GSM, RF or other) and wireless interface for close communication BIBK 12 (Wi-Fi, Lora, RF or other);

• BUP 13 is a flight control unit and is located on board the UAV. It contains a control microcontroller UMK 15, GPS-receiver GPS 16, control unit for electric motors BUED 17, wireless interface for close communication BIBK 18, altimeter BM 19 and wireless interface for long-distance communication BIDK 20, connected in one information bus to UMK 15 The UAV is powered by ED24 electric motors;

• BIM 14 is an onboard information module and is located on board the UAV. It is made of an information microcontroller IMK 21, connected informationally to UMK 15, and to its input through an amplifier-limiter UO 22 is connected a downward photodetector ФП 23;

• NM 25 is a guidance module that coordinates the landing by directing the UAV to the center of the PC. It is located in the Host Country and is informationally connected to SPS 2. It contains a directing microcontroller NMC 26, connected to GC 8 and through modulating drivers MD 27 controls the laser diodes LD 28-5-34;

• PC 36 is a UAV landing pad. Located at the Host Party. Represents a square with dimensions in accordance with those of the UAV. Around it, in the four corners are mounted the laser diodes LD 30, 31, 32 and 33 (angle lasers), directed upwards. Another LD 28 (central) is installed right in the middle of the site. Its light in a narrow beam is also directed upwards. Thus, the beam of the central laser LD24 falls in the area between the four beams of the angular lasers. From a certain height upwards, the directional diagrams of the angular lasers overlap at their periphery. In addition, on two opposite sides of the site (the figure is "north and south") are mounted another additional LD 29 and LD 34, whose radiation patterns partially overlap with the beams of the angular lasers located on the respective side of the site. If necessary (for example, when landing on a moving object, the curtain can be expanded with two additional lasers;

• ZOBK 37 is an area for close communication between UAV and SPS 2 (marked with a dotted circle). The center of this zone is positioned "east" of PC 36 and is determined by a cylinder with a base diameter twice the absolute horizontal error (the greater error Δ X (or ΔΥ) of the GPS receiver on coordinates X or Y), and in height twice the absolute error ΔΖ on the coordinate Z;

• 03 35 is an optical curtain, which is formed by the upward laser beams of LD 28 -e- 34. Its height must be higher than ZOBK 37 and at the same time provide a sufficiently high level of the optical signal to have reliable communication. with FP 23.

List of abbreviations used

1. UAV - unmanned aerial vehicle with vertical landing (drone);

2. SIS - station of the sending country;

3. SPS - station of the host country;

4. PC - landing site;

5. GC - main computer;

6. BIDK - wireless interface for long distance communication;

7. BIBK - wireless interface for close communication;

8. IDC - interface for long distance communication;

9. BUP - flight control unit;

10. U MK - control microcontroller;

11. GPS - GPS receiver;

12. BUED - control unit for electric motors;

13. VM - altimeter;

14. BIM - on-board information module;

15. IMC - information microcontroller;

16. MA - amplifier-limiter;

17. FP - photodetector;

18. NM - guiding module;

19. NMC - directing microcontroller;

20. MD - modulating drivers;

21. LD - laser diode;

22. 03 - optical curtain;

23. ZOBK - area for close communication;

24. X, Y, Z - geometric coordinates relative to the landing site;

25. ΔΧ, ΔΥ, ΔΖ - the absolute errors of the geometric coordinates.

V. Example of embodiment of the invention

An exemplary embodiment of a system for automatic guidance of unmanned aerial vehicles during vertical landing, according to the invention, is shown with its functional diagram in fig. 1.

The system includes SIS1 and SPS2. SIS 1 contains GK 3, BIDK 4, GPS 5, IDK 6 and BIBK 7, and SPS 2 contains their equivalent GK 8, BIDK 9, GPS 10, IDK11 and BIBK 12.

On board the UAV are BUP 13 and BIM 14. BUP 13 is made up of UMK 15, GPS 16, BUED 17, BIBK 18, VM 19 and BIDK 20, which are connected via an information bus to UMK 15. BIM 14 is managed by IMC 21, which is informationally connected to UMK 15, and its input is connected through MA 22 with downward-facing FP 23. The UAV is powered by electric motors ED 24.

In addition to SPS 2, in the Host country, there is an additional HM 25, including a directing microcontroller NMC 26, informationally connected to GC 8 and controlling through modulating drivers MD 27 laser diodes LD 28 + 34, forming an optical curtain 03 35 over PC 36. 36 falls the virtual ZOBK 37.

The logistics of the flights between SIS 1 and SPS 2 are carried out through their GC 3 and 8 through their IDCs 6 and 11. The connection between SIS 1 and UAVs is carried out through BIDC 4 and BIDC 20.

When the UAV arrives at the assigned coordinates of ZOBK 37, a connection is made with SPS 2 through their BIBK 12 and 18. BUP 13 on board the UAV sends a message to SPS 2 and SIS 1 that it is ready to land. Then (possibly with permission) NM 25, through NMC 26 and MD 19, includes all lasers LD 28 * 34 and their optical signal is modulated synchronously with an identification code for site initialization. The UAV receives permission to land and moves forward to the set coordinates of PK36 at a reduced relative speed. The BIM 14 monitors the receipt of the optical signal and code coming through the downwardly directed FP 23 and MA 22 in IMC 21. MA 22 is designed to amplify the optical signals and limit any parasitic optical signals with low or very high level. Weak signals can be received peripherally away from the rays, and strong - when descending to PC 36. IMC 21 detects the received code of PC 36, which means that the UAV has entered the area of 03 35. BUP 13, through BIBC 18 and 12 informs about this SPS 2, GK 8 on which sets the mode of NM 25 to start scanning (sequentially in time) switching on the lasers. The scanning period for all lasers is several tens to one hundred milliseconds, which ensures that the drone, flying relatively slowly over the optical curtain, will not deviate from it and lose the directional signals and BIM 14 will be able to reliably receive optical signals. If the LEDs are infrared, their duration of illumination must comply with safety standards.

The beam of each laser is modulated with its identification code indicating its position relative to the center of the PC 36. The signals are received by the FP 23, processed in the IMC 21 and the information is submitted to the IMC 15, which indicates in which direction to direct the UAV. to fall above the beam of the central LD 28.

Thus, if the UAV falls over LD 29, it must be directed in a "south" direction. When it falls above laser 30, respectively, the direction is "south-west", above laser 31 it is "south-east", above laser 32 - "north-west", above laser 33 "northeast" and above laser 34 - on "North". These instructions consistently direct the UAV to the final destination - the central LD 28. Landing above it, the landing is carried out by following the laser beam down and controlled by VM 19 of BUP 13. If for some reason you get out of it, the UAV makes circular motions until one of the rays hits and continues to aim and land. In case of failure, the UAV can return to ZOBK 37 and repeat the landing attempt. UAV flight plans always provide for different variants of "emergency mode".

In a stationary PC, finding the central beam of the LD 19 makes it possible to apply algorithms for differential GPS, as its X and Y coordinates are the exact coordinates of the center of the PC 36. From there, the error of the GPS coordinates can be corrected. the receiver on board the UAV and on them and with the beam of LD 19 to make a correction of the landing trajectory.

When the PC 36 is mounted on a moving object (motor vehicle, vessel, train or other), the GPS coordinates of the PC 36 become a variable, which is obtained from GPS 10. The center of the virtual ZOBK 37 also becomes a variable. The orientation of the PC 36 on the movable object is chosen according to the ease of installation and convenient approach for landing, namely on the side of the object in the direction of travel to equalize the speeds of the two objects before landing.

When moving, the mobile object changes its orientation and the "east-west-north and south" directions also become variable. In this case, the center of ZOBK 37 is mobile and is calculated by GK 8 of SPS 2 on the basis of incoming GPS data as variables related to the geometry of PK 36 relative to the moving object and the motion vector of the object. It is determined by the current GPS coordinates of the moving PC 36 by correcting the doubled absolute error of the GPS horizontally Δ X (or ΔΥ) in the direction perpendicular and to the right of the motion vector. The coordinates of the center of ZOBK 37 are continuously exchanged between SPS 2 and SIS 1, as well as between the two BIBK 12 and 18 after establishing the connection between them.

If in fig. 1 the site with the site moves in the direction conditionally "south-north", regardless of where it rotates, following the movement, the center of ZOBK 37 after the calculations will always go perpendicular to the right of it (conditionally "east"). Thus, in the case of a mobile object, the subsequent landing procedures coincide, because the center of ZOBK 37 remains in a constant geometric orientation with PK 36. After positioning the UAV in ZOBK 37, it attaches to them and begins the landing process, as shown in the figure. at a stationary site.

In this case, an additional error appears from GPS 10 (or 5), which is mounted below the center of PC 36 and if it is away from it, the distance must be taken into account in the transmitted coordinates. If the error is large, 03 35 should be extended by inserting the additional two LDs as noted above. If space is limited, they may be closer to the PC 36 and point sideways upwards at an angle.

If for some reason some of the lasers do not emit a signal (without the central one), the system can function, because each beam autonomously directs the UAV to the center. It only increases the likelihood of him losing the site, especially with moving objects.

In principle, in case of loss of connection with the optical curtain, it switches to the “search” mode, ie zigzag movement progressively with a small step along the “east-west” axis or, in extreme cases, going back to the position in the center of ZOBK 35 and resumption. of the landing attempt. In case of failure, both parties are informed and the adopted emergency regime is followed.

With this geometric configuration and the presence of identification numbers of the individual laser beams, it is possible for BIM 14 to distinguish which of the guide lasers are not included. For some of the options, accordingly, it is possible to choose a suitable landing algorithm. For example, if lasers 30 and 32 are not lit, the UAV will pass over them without identifying them and will reach laser 31 or 33. Then instead of "southeast" or "northeast", respectively, it will have to move to "north "Or" south "until it is positioned between the two beams 31 and 33. It will then return to the" East "and fall over the central beam of LD 28. If the UAV flies over an extinguished laser 31 or 33, it will move away "west" of the site. When it moves away from the center of the site more than twice the allowable absolute error ΔΥ (ΔΥ) to the "west", it means that it has either missed the curtain or has a non-luminous laser 31 or 33. In this case, the UAV must return in a position in the center of

ZOBK and resume the landing attempt, but goes into "search" mode. Move to PK36 on the east-west axis in a zigzag motion (north-south) with amplitude Δ X until the site is found and the working beams are identified. According to the result, for some configurations with non-operating lasers, a suitable algorithm can be applied to detect the beam of the central laser 19. If the latter does not work, landing is impossible in principle. It is possible to land if LD 31, 31, 32 and 33 are used, but with more maneuvers.

For non-luminous lasers, the landing time can be significantly increased due to the increase in landing attempts.

VI. Use of the invention

The system described above according to the invention is useful for sending unmanned aerial vehicles from one point to another and returning them. It allows automatic landing on a small landing site using free data from the civil GPS system, the coordinates of which have a significantly larger error than the size of the site. With the addition of a GPS receiver in the receiving country and appropriate software, the system can also be successfully applied when landing on moving objects.

VII. References:

[1] Fumio Ohtomo, Kazuki Osaragi, Tetsuji Anai, Hitoshi Otani, US Grant Patent number 8630755B2, “Automatic taking-off and landing system”, 2014.

[2] Fumio Ohtomo, Kazuki Osaragi, Tetsuji Anai, Hitoshi Otani, US Grant Patent number US20120277934A1, “Taking-Off And Landing Target Instrument And Automatic Taking-Off And Landing System”, 2011.

Claims (1)

VIII. COPYRIGHT CLAIMS ή System for automatic guidance of unmanned aerial vehicles in vertical landing, built by a station of the sending country 1, which contains a main computer 3 and information-related wireless interface for long-distance communication 4, GPS-receiver GPS 5, interface for long-distance communication 6 and a wireless interface for close communication 7, and in the receiving country there is an identical station on the receiving side 2, which contains a host computer 8 and information-related wireless interface for remote communication 9, GPS receiver 10, interface for remote communication 11 and wireless interface for close communication 12, and on board the unmanned aerial vehicle is a flight control unit 13, which contains a control microcontroller 15 and information-related GPS receiver 16, control unit 17 for electric motors 24, wireless interface for close communication 18, altimeter 19 and wireless interface for long distance communication 20, characterized by that the control microcontroller (15) is connected to the on-board information module (14) through its information microcontroller (21), to the input of which, through an amplifier-limiter (22) is connected a downwardly directed photodetector (23) and the host computer 8) at the station of the receiving side (2) is connected to a directing module (25) by its directing microcontroller (26), which controls the laser diodes (28, 29, 30, 31, 32, 33, 34) through the modulating drivers (27) ), which are located on and around the landing site (36) and directed upwards, with a central laser diode (28) placed in its center, and in the four corners of the site there is one laser diode, respectively (30, 31, 32). and 33) on both opposite sides of the site (36) are placed one additional laser diode, respectively (29) and (34), as the line connecting their centers passes through the center of the site and forms one of the directions for its orientation, and the diagrams of all are positioned so that they overlap in part with its adjacent laser diodes above a certain height above the platform, forming a dense optical curtain (35) above it, and in addition, perpendicular to the orientation line, crossing the center of the landing site, is the other orientation line, at a distance exceeding twice the absolute horizontal error of the UAV GPS (16) is the projection in the plane of the site (36) of the virtual center of a zone for close communication (37).