AIRCRAFT, LIGHTNING-PROTECTION SYSTEM, AND METHOD OF PROVIDING THE LIGHTNING PROTECTION

Abstract

The invention relates inter alia to a drone (10) comprising at least one electromotive drive (24a, 24b) and a controller (33, 33a, 33b), wherein the drone can permanently maintain a set flight position with the aid of the controller, wherein the drone that is in the flight position thereof is connected to a ground station (11) by a cable (13), wherein the cable comprises at least two electrical conductors (27a, 27b, 27c, 27d, 27e, 27f, 27g) for supplying voltage to the drive, wherein the drone comprises lightning-protection means (34a, 34b, 34c) that protects the controller and/or the drive and/or other electronic component parts of the drone from lightning strikes, wherein the overall cross section of the electrical conductors of the cable allows for high electrical currents, caused by lightning strikes, to be conducted away from the drone (10) to the ground station (11), and wherein the cable is connected to a lightning transfer point (16) in the earth (15), in the region of the ground station.

Claims

1. A drone comprising: an electromotive drive; a controller connected to the drive for maintaining the drone in a set flight position; a cable connecting the drone in its flight position to a ground station and having at least two electrical conductors for supplying voltage to the drive; and lightning-protection means for protecting the controller and/or the drive and/or other electronic component parts of the drone from lightning strikes, an overall cross section of the electrical conductors of the cable being capable of conducting for high electrical currents caused by lightning strikes away from the drone to the ground station, the cable being connected to a lightning transfer point in the earth in the region of the ground station.

2. The drone according to claim 1, wherein the lightning transfer point is at a depth in the earth of at least 1 m.

3. The drone according to either claim 1, wherein the lightning-protection means comprises a surge arrester and/or has a redundant configuration of electronic component parts of the drone.

4. The drone according to claim 1, wherein the electrical conductors of the cable are copper conductors.

5. The drone according to claim 1, wherein an overall cross section of all the electrical conductors of the cable is at least 5 mm.sup.2.

6. The drone according to claim 1, wherein the flight position of the drone can be set.

7. The drone according to claim 1, wherein the cable comprises a plurality of conductors, all or at least some of which contribute to conducting away lightning strikes.

8. The drone according to claim 1, further comprising: a communications unit that can establish wireless communication with other subscribers of a radio network.

9. The drone according to claim 8, wherein the cable has a fiber optic cable that can transmit data from the ground station to the communications unit and/or that can transmit data from the communications unit to the ground station.

10. A lightning-protection system for achieving lightning-protection for a site, comprising: a ground station, a drone having an electromotive drive and a controller for keeping a flight position once the position has been set, a cable having connecting the drone to the ground station and having two electrical conductors for supplying voltage to the drive, the cable conducting lightning away from the drone, and means for connecting the cable directly or indirectly to the earth.

11. The lightning-protection system according to claim 10, wherein the drone comprises lightning-protection means.

12. The lightning-protection system according to claim 11, wherein the lightning-protection means protects the controller and/or the drive from lightning strikes.

13. The lightning-protection system according to claim 10, wherein an overall cross section of the electrical conductors of the cable is sufficiently large to conduct high electrical currents caused by lightning strikes away from the drone to the ground station.

14. The lightning-protection system according to claim 10, wherein the cable is connected to a lightning transfer point in the earth in the region of the ground station.

15. The lightning-protection system according to claim 1, wherein the lightning-protection system comprises a plurality of the drones that each remain in their respective flight positions at a specified spacing from one another.

16. The lightning-protection system according to claim 10, wherein the lightning-protection system comprises a plurality of ground stations.

17. The lightning-protection system according to claim 15, wherein one ground station is connected to respective drone.

18. The lightning-protection system according to claim 10, wherein the ground station is mobile.

19. The lightning-protection system according to claim 10, wherein the lightning-protection system is mobile.

20. A method of providing lightning-protection for a site, the method comprising the following steps: providing a ground station, a drone and a cable having electrical conductors having a sufficiently large overall cross section capable of conducting away high electrical currents caused by lightning strikes, connecting the drone to the ground station by the cable and electrically connecting the cable to the earth, setting a flight position for the drone, and maintaining the set flight position using a controller in the drone, supplying the drone with operating current from the ground station via the cable, providing lightning-protection for the site by conducting away into the earth via the cable the lightning that has struck the drone in the event of a lightning strike.

Description

[0074] Further advantages can be found in the dependent claims, which have not been cited, and with reference to the following description of the embodiments shown in the drawings. In the drawings:

[0075] FIG. 1 is a partially sectional schematic view of a first embodiment of a drone according to the invention and of a lightning-protection system according to the invention comprising a ground station that is shown schematically and is connected to a drone by a cable (shown by broken lines), which drone assumes a set flight position above an event site,

[0076] FIG. 2 is a schematic cross section, approximately according to the line II-II in FIG. 1, of a first embodiment of a cable for providing a connection between the drone and the ground station, the cable comprising two conductors,

[0077] FIG. 3 shows a section through a further embodiment of a cable, in a view according to FIG. 2, comprising seven conductors,

[0078] FIG. 4 shows a further embodiment of a drone according to the invention and a lightning-protection system according to the invention, in a view according to FIG. 1, the drone additionally comprising a communications unit for providing a radio network,

[0079] FIG. 5a shows an embodiment of a cross section of cable, also comprising a fiber optic cable, approximately according to the cutting line V-V in FIG. 4,

[0080] FIG. 5b shows a further embodiment of a cross section of the cable, in a view according to FIG. 5a,

[0081] FIG. 6 is an enlarged partially sectional schematic view, in the manner of a block diagram, of an embodiment of a drone, approximately according to the pitch circle VI in FIG. 1, some electronic components of the drone being shown,

[0082] FIG. 7 shows a further embodiment of a drone in a view according to FIG. 6, a communications unit additionally being provided,

[0083] FIG. 8 shows a further embodiment of a drone according to the invention in a view according to FIG. 6, modified lightning-protection means being provided,

[0084] FIG. 9 shows a further embodiment of a drone in a view according to FIG. 6, modified lightning-protection means again being provided, and

[0085] FIG. 10 is a schematic plan view of an event site over which a plurality of drones, in the embodiment of FIG. 10 a total of six drones, are arranged for lightning-protection purposes, which devices are mutually spaced by a specified maximum spacing and are arranged in the manner of grid points.

[0086] Embodiments of the invention are described by way of example in the following description of the figures, with reference to the drawings. In this case, for the sake of clarity, even if different embodiments are involved, the same or comparable parts or elements or regions are provided with the same reference signs, small letters sometimes being added.

[0087] Within the context of the invention, features that are described only with reference to one embodiment can also be provided in all other embodiments of the invention. Embodiments modified in this way are also covered by the invention, even if they are not shown in the drawings.

[0088] All the features disclosed are per se essential to the invention. The disclosure of the associated priority documents (copy of the prior application), the cited documents, and the described apparatuses of the prior art is hereby included in its entirety in the disclosure of the application, also for the purpose of incorporating individual or a plurality of features of said documents into one or more claims of the present application.

[0089] The drone, denoted in its entirety by 10, forms an essential component of a lightning-protection system that is denoted in its entirety by 36 overall in the figures. This will be explained in the following, first with reference to an embodiment according to FIG. 1:

[0090] FIG. 1 shows the drone 10 at a spacing H (shown discontinuously, i.e. not to scale), known as the flight altitude, above the ground 41.

[0091] The drone 10 is connected to a ground station 11 by cable 13. The drone 10 thus hovers above a site, in particular above an event site 12 shown in FIG. 1.

[0092] In the figures, the drone is shown schematically in the form of a drone. However, the invention in particular also covers the case of the drone 10 being designed in the manner of a helicopter or as a helicopter.

[0093] Helicopters are understood in particular to be drones that comprise at least one rotor that rotates about a substantially vertical axis of rotation. In helicopters of this kind, for example angle adjustment of the rotor blades may also take place, using a swash plate, as is known in conventional helicopters for setting the pitch, i.e. setting the inclination or the angle of attack of the rotor blades.

[0094] The lightning-protection system 36 is used as a whole for protecting visitors to the event site 12, schematically shown in FIG. 1 as people 17a, 17b, 17c, but also employees, such as musicians 19, from being struck by lightning 14 (shown schematically). By means of the drone 10, the cable 13, and a lightning transfer point 16 arranged within the earth 15, the lightning is safely conducted into the earth, such that the visitors and participants at the event are not in danger.

[0095] The drone 10 is arranged at a flight altitude H, above the event site 12. The flight altitude H is in particular higher than the altitude HE of elevations 21 that may be arranged in the region of the event site 12, and also higher than the altitude HB of buildings 20 that may be arranged in the event site 12.

[0096] In this respect, in the region or site 12 to be protected by the lightning-protection system 36, the drone 10 is located, in its flight position, at an elevated, in particular at the highest, point. This ensures that lightning 14 first strikes the drone 10 before it hits the ground 41 at another position within the event site 12.

[0097] As shown in the schematic FIG. 1, the drone 10 may comprise one or more feet 22a, 22b in order to be able to land safely on the ground 41 again after use. However, feet of this kind are not necessarily required in the drone 10 according to the invention.

[0098] The drone 10 further comprises a chassis 23 or another type of frame or structure. The chassis in particular carries a controller 33 as well as further electronic or electromechanical components of the drone.

[0099] In the embodiment of FIG. 1, the drone comprises two rotors 25a, 25b (indicated merely by way of example) that are each assigned a separate drive 24a, 24b. The drive is an electromotive drive, i.e. an electric motor. The number of rotors is arbitrary. In this case, conventional arrangements or embodiments of rotors and the drives thereof for what are known as multicopters can be used. For example, 1 to 16 drives and/or motors and rotors may be provided.

[0100] As indicated in the embodiment of FIG. 1, one or more lightning antennae 26 may be provided on the drone 10. Said antennae may in particular comprise a metal element or a metal conductor which ends in an exposed position in any form, or protrudes from the shell contour of the drone 10 in another manner, and/or may be formed by or together with a chassis 23 or housing or another component of the drone.

[0101] The electronics or controller 33 of the drone 10, and in particular also the electromotive drives 24a, 24b for the rotors 25a, 25b are supplied with operating voltage from the ground station 11 by the cable 13.

[0102] The drone 10 can thus permanently maintain and keep a flight position, for example for several hours or days, which position is set once. For this purpose, the ground station 11 is connected for example to a current generator or to the conventional voltage supply network. The operating voltage is transmitted from the ground station 11 to the drone 10 by the cable 13.

[0103] FIG. 2 is a cross section of a first embodiment of cable 13. The cable 13 according to FIG. 2 comprises just two conductors 27a, 27b. Said conductors consist of a metal material, in particular copper. Said conductors may be surrounded by insulating sheathing 39a, 39b. The cable 13 can furthermore also comprise stabilizing material 40, in particular a material of the kind that also consist of insulating material.

[0104] Advantageously, the cable 13 is as lightweight as possible overall. This requirement is easy to follow because the overall length of the cable 13 may not exceed the maximum useful/bearing load of the drone 10.

[0105] The cross section of the two conductors 27a, 27b of the cable according to FIG. 2 is particularly important. In the embodiment of the invention, said overall cross section is at least 10 mm.sup.2. The overall cross section can be divided over the two conductors 27a, 27b in equal or unequal parts.

[0106] In the embodiment of FIG. 2, the cable 13 comprises just two electrical conductors 27a, 27b. In normal circumstances, i.e. when no lightning strikes occur, said conductors are used for transmitting operating voltage from the ground station 11 to the drone 10. The two conductors 27a, 27b can also be used for transmitting control information from the ground station to the drone 10, or in the opposite direction. The control information may be used for example for setting or amending or checking the flight position of the drone 10.

[0107] In a further embodiment of the invention, it may be possible for control information for setting or amending the flight position of the drone to be transmitted from the ground station or a mobile controller or another controller on the ground, to the drone 10, wirelessly or by radio.

[0108] In the embodiment of FIG. 2, the two conductors 27a, 27b have a sufficiently large cross section, or a sufficiently large overall cross section of at least 10 mm.sup.2, to be able to transmit the extremely high currents caused in the case of a lightning strike from the drone 10 to the ground station 11 and into the earth 15, via the cable 13.

[0109] A connecting cable 32 is arranged in the region of the ground station 11, which connecting cable is guided into the earth 15, at a depth T of preferably approximately 3 meters or more than 3 meters, as far as a transfer point 16. At said point, the lightning strike is transferred to the earth. In this respect, the lightning transfer point 16 is at earth potential or is earthed.

[0110] In the case of a lightning strike into the drone 10 according to FIG. 1, the lightning is thus conducted directly into the earth 15. The event on the event site 12 need not be interrupted or stopped, because the visitors 17a, 17b, 17c and the artists 19 are not in danger.

[0111] It should be noted that the music event according to FIG. 1 is just one example for possible applications of the lightning-protection system 36 according to the invention.

[0112] According to the embodiment of FIG. 3, the cable 13 comprises a plurality of conductors 27a, 27b, 27c, 27d, 27e, 27f, 27g. Said conductors are each surrounded by insulating sheathing 39b, 39c, only some isolating sheathings being provided with reference signs in FIG. 3.

[0113] The arrangement of the conductors 27a, 27b, 27c, 27d, 27e, 27f, 27g in the embodiment of FIG. 3 is to be understood merely by way of example. The individual cross sections of the individual conductors may also be the same, as shown in FIG. 3, but may also be entirely different.

[0114] It is advantageous for the cable 13 to comprise a plurality of conductors, and for a plurality of said conductors, preferably all the conductors, to participate in conducting away the currents caused by a lightning strike. Specifically, the overall cross section of the conductors can then be kept particularly small. In the case of lightning being conducted away, specific physical effects occur in electrical conductors. Said effects mean that, by distributing the conductor cross sections used for conducting away the lightning over as many conductors as possible, the overall cross section can be kept smaller as a whole.

[0115] The conductors provided on the cable 13 are advantageously not only used for arresting the lightning in the case of a lightning strike, but are also used in normal flight operation of the drone 10. The conductors 27a, 27b, 27c, 27d, 27e, 27f, 27g can thus not only transmit operating voltage, but can for example also transmit information, unidirectionally or bidirectionally, between the drone and the ground station 11.

[0116] According to the embodiment of FIG. 4, the drone 10 additionally comprises a communications unit 28. Together with outstations 29a, 29b that are arranged for example on the ground 41, said communications unit can form a radio network. Audio data or video signals or other information or data can be transmitted via said radio network.

[0117] The cable 13 provided in this embodiment is shown in cross section in FIG. 5a. It can be seen here that a fiber optic cable 30 is provided in addition to four electrical conductors 27a, 27b, 27c, 27d. The number of electrical conductors 27a, 27b, 27c, 27d was selected merely by way of example in this embodiment. For example, the two conductors 27a and 27b can be used for transmitting an operating voltage for the drives of the drone 10. In contrast, the two further conductors 27c and 27d can provide for transmission of the operating voltage for the communications unit 28.

[0118] However, the conductors can also be used for other different applications, and different voltages or different signals may be transmitted.

[0119] Optical signals can be transmitted via the fiber optic cable 30, it being possible for electro-optical or optoelectronic transducers to be provided both in the region of the ground station 11 and in the region of the drone 10. However, the high current generated in the case of a lightning strike cannot be conducted away through the fiber optic cable. The electrical conductors 27a, 27b, 27c, 27d are provided for this purpose, the overall cross section of which conductors again amounts to at least 5 mm.sup.2, preferably at least 10 mm.sup.2.

[0120] Radio data can be transmitted unidirectionally or bidirectionally via the fiber optic cable 30 in order for the drone 10 to be able to participate in the radio network as a subscriber.

[0121] However, information, data and signals can also be transmitted between the ground station 11 or a controller 31 of the ground station 11, and the drone 10 or a controller 33a, 33b of the drone 10 can also be transmitted via the fiber optic cable 30, for example in order to control and/or to influence and/or to correct the flight position of the drone 10.

[0122] Of course, the illustration by way of example of a cross section of the cable 13 according to FIG. 5a, just like that according to FIGS. 2 and 3, is to be understood to be merely schematic. Advantageously, the cable has an overall cross section that is substantially circular or that approximates a circle or that is in any case free of projections, and in which all the electrical and optical conductors, if provided, are integrated.

[0123] According to the embodiment shown schematically in FIG. 5b, the fiber optic cable 30 consists of twelve individual fiber optic strands 30a, 30b, 30c, the remaining fiber optic strands being shown but not provided with reference signs. The number of fiber optic strands is irrelevant, however. The bundle of the twelve fiber optic strands 30a, 30b, 30c is arranged approximately over a substantially circular cross section. Furthermore, a sheath 44 can optionally be provided.

[0124] Twelve electrical conductors 27a, 27b, 27c, etc. are arranged around said sheath 44. A further sheath 45 is provided around said twelve conductors, such that the cross section of the cable according to FIG. 5b forms a substantially circular cross section overall. The sheath 45, as well as the sheath 44, may consist of plastics material or a textiles material for example. A material such as PVC or polyurethane is furthermore possible.

[0125] In order to avoid repetitions, with respect to the design of a drone 10 using a communications unit 28 for forming a radio network reference is made to the subsequently published German patent application DE 10 2017 105 956.3 [US 2018/0273171] by the applicant, the contents of which is hereby included in the contents of the present patent application, also for the purpose of incorporating individual features in the claims of this application.

[0126] The design of a drone 10, shown in the manner of a block diagram, will now be explained in accordance with FIG. 6.

[0127] In this embodiment, the drone 10 (shown by way of example) comprises two lightning antennae 26a, 26b. The number of lightning antennae 26 is arbitrary, however. FIG. 6 is merely intended to show that the lightning antennae 26a, 26b can protrude outwards from a housing 42 of the drone 10 or from a shell contour 42 of the drone 10.

[0128] In this embodiment, the lightning antennae 26a, 26b are directly connected to the cable 13. Since FIG. 6 is an illustration in the form of a block diagram, the detailed connection is not shown here.

[0129] In the simplest case, the cable 13 can be used for supplying voltage to the drone 10 and can additionally comprise an electrical conductor that is provided as a separate conductor for conducting away the lightning current.

[0130] FIG. 6 actually shows that the lightning antennae 26a, 26b are directly connected to the cable 13. In this case, it may be possible for an electrical connection to be established, in some circumstances only briefly, among a plurality of conductors 27a, 27b, 27c, 27d, 27e, 27f, 27g on the cable 13 for example, in the case of very high voltages or very high currents occurring. In contrast, in normal circumstances, i.e. in the case of no lightning striking, the individual conductors 27a, 27b, 27c, 27d, 27e, 27f, 27g can be electrically isolated from one another.

[0131] In the embodiment of FIG. 6, a controller 33a of the drone 10 is provided that is connected to the cable 13 via an electrical cable 35b, an electronic component part 34e and a further electrical cable 35a. The controller 33a is connected to the motorized drive 24a for the rotor 25a by an electrical cable 35c. At the same time, the controller 33a is connected to the electromotive drive 24b for the rotor 25b by an electrical cable 35d.

[0132] As is already the case in the previous embodiments, the number of rotors 25a, 25b is arbitrary.

[0133] The controller 33a ensures or jointly ensures that a set flight position of the drone 10 at a flight altitude H above the event site 12 is maintained. For this purpose, said controller can supply the rotors 25a, 25b with the necessary supply voltage for the drives 24a, 24b and also with the necessary motor capacity. Similarly, for example one or more position sensors may also be provided in the drone 10 and connected to the controller 33a in order to maintain a set flight position even in the event of wind, and over long time period of for example several days.

[0134] In normal circumstances, the controller 33a receives its supply voltage via the cable 13. According to the embodiment of FIG. 6, the lightning antenna 26b is likewise connected to the cable 13. In order to then prevent the controller 33a from failing in the event of a lightning strike, a lightning-protection means 34a is provided. According thereto, the lightning controller 34a is provided between the cable 13 and the controller 33a.

[0135] The lightning-protection means 34a may be a surge arrester for example. In the event of high voltages occurring, i.e. in the case of a lightning strike, at the input side of the lightning-protection means 34a, a permanent or brief interruption of the connection between the controller 33a and the cable 13 can be ensured in order to protect the controller 33a from voltages or currents that are too high.

[0136] In order to ensure brief bridging, the controller 33a may for example also be connected to a battery 43 which bridges brief outages in the voltage supply.

[0137] Alternatively, the controller 33a can also be designed, in interaction with the lightning-protection means 34a, in such a way that the controller automatically intervenes again immediately after a brief outage, for example after just fractions of a second.

[0138] The lightning-protection means 34a ensures in any case that the controller 33a and all the electronic component parts and devices connected thereto, for example also the electromotive drives 24a, 24b, are protected from surges.

[0139] In addition, the housing 42 of the drone 10 can be designed in the manner of a Faraday cage and can ensure that no undesired high voltages can penetrate into the interior of the Faraday cage 42 itself.

[0140] According to the embodiment of FIG. 6, the controller 33a is furthermore redundant. For this purpose, the second controller 33b is provided with a second lightning-protection means 34b and the corresponding connecting cables 35e, 35f, 35g, 35h.

[0141] In the event of the controller 33a failing for any reason, for example because the lightning-protection means 34a has failed, the controller 33b can immediately take over the control of the drone. For this purpose, all the relevant information can be permanently reflected to the two controller 33a and 33b even while the drone 10 is being programmed, for example while the flight position is being set.

[0142] For the sake of clarity, it is noted that the controller 33a, 33b may for example comprise microprocessors and also memories, for example volatile and non-volatile memories.

[0143] The embodiment of FIG. 7 relates to an assembly that substantially corresponds to the drone 10 of FIG. 6. In this case, a communications unit 28 is additionally provided, as has already been explained in the embodiment of FIG. 4 and FIG. 5a.

[0144] In this embodiment, the communications unit 28 is also assigned lightning-protection means 34c which ensures, in the case of a lightning strike, that the communications unit 28 continues to remain able to communicate. In an embodiment of the invention the communications unit 28 may also be redundant (not illustrated in FIG. 7), in order to thus ensure for increased failure-safety.

[0145] The embodiment of FIG. 8 relates to an assembly that is modified compared with the embodiment of FIG. 6. In this case, the lightning-protection means 34a, 34b is directly connected to the controller 33a and 33b, respectively, but is not directly connected to the cable 13.

[0146] The embodiment of FIG. 9 finally shows a further alternative design. In this case, a lightning-protection means 34a, 34b is again provided and is connected to the relevant controller 33a, 33b. In this case, however, the corresponding lightning antenna 26a, 26b is directly connected to the relevant lightning-protection means 34a, 34b.

[0147] The embodiment of FIG. 10 shows a lightning-protection system in which a plurality of drones 38a, 38b, 38c, 38d, 38e, 38f of the type according to the invention are used. FIG. 10 is a view from above of an event site 12, only the drones 38a, 38b, 38c, 38d, 38e, 38f being shown. Said devices are arranged at regular spacings, in the manner of grid points or in the manner of a raster. The maximum spacings are denoted MAX or MAY. The raster develops along an X-Y plane. All the drones 38a, 38b, 38c, 38d, 38e, 38f may be arranged at the same flight altitude H or at different altitudes.

[0148] It has been found that adhering to maximum spacings of 80 meters (i.e. MAX=80 meters and MAY=80 meters) already makes it possible to ensure sufficient protection from lightning strikes. The invention also covers maximum spacings of for example 40 meters or less between two adjacent drones.

[0149] The ground station 11 can also comprise lightning-protection means (not shown in the drawings), in order for example to protect a controller 31 of the ground station 11 and/or other electronic or electrical elements of the ground station 11 from being impaired or damaged by lightning strikes.