Abstract
A method for operating a mine-sweeping system and corresponding mine-sweeping system, wherein the mine-sweeping system includes at least one drone for detonating sea mines. The drone has at least one magnet element for magnetically detonating the sea mines. The method includes a) translationally moving the at least one drone in the water and b) carrying out a first rotational movement of the drone with respect to a first degree of rotational freedom.
Claims
1.-15. (canceled)
16. A method for operating a mine-sweeping system, wherein the mine-sweeping system comprises at least one drone for detonating sea mines, wherein the drone comprises at least one magnet element for magnetically detonating the sea mines, wherein the method comprises: a) translationally moving the at least one drone in the water, and b) carrying out a first rotational movement of the drone with respect to a first degree of rotational freedom, characterized in that the drone has a longitudinal axis, wherein the first degree of rotational freedom corresponds to a rotational movement about the longitudinal axis.
17. The method as claimed in claim 16, further comprising: c) carrying out a rotational movement of the drone with respect to an additional second degree of rotational freedom.
18. The method as claimed in claim 17, further comprising: d) varying a diving depth of the drone.
19. The method as claimed in claim 16, wherein the at least one magnet element of the drone is a permanent magnet.
20. The method as claimed in claim 16, wherein the at least one magnet element of the drone is an electrical coil element.
21. The method as claimed in claim 20, further comprising: e) varying an operating current of the electrical coil element over time.
22. The method as claimed in claim 16, wherein the drone is a self-driven drone.
23. The method as claimed in claim 16, wherein steps a) and b) take place simultaneously.
24. The method as claimed in claim 16, wherein steps a) and b) take place successively.
25. The method as claimed in claim 16, wherein the mine-sweeping system comprises a plurality of drones for detonating sea mines.
26. A mine-sweeping system, comprising: at least one drone for detonating sea mines, wherein the drone comprises at least one magnet element for magnetically detonating the sea mines, wherein the drone comprises at least one control element for bringing about a first rotational movement of the drone with respect to a first degree of rotational freedom, wherein the drone has a longitudinal axis, wherein the first degree of rotational freedom corresponds to a rotational movement about the longitudinal axis.
27. The mine-sweeping system as claimed in claim 26, wherein the at least one drone is a self-driven drone.
28. The mine-sweeping system as claimed in claim 26, wherein the control element is a rudder, a flap, or a motor.
29. The mine-sweeping system as claimed in claim 26, wherein the mine-sweeping system comprises a plurality of drones for detonating sea mines.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0047] The invention is described below using a number of exemplary embodiments with reference to the attached drawings, in which:
[0048] FIG. 1 shows a schematic illustration of a magnetic signature, to be reproduced, of a ship,
[0049] FIG. 2 shows a schematic sectional illustration of a mine-sweeping system according to a first exemplary embodiment of the invention,
[0050] FIG. 3 shows a rectangular coil,
[0051] FIG. 4 shows a three-dimensional profile for a magnetic flux density formed with the rectangular coil of FIG. 3,
[0052] FIG. 5 shows the dependency of the magnetic flux density on the distance from the coil center for various directions in space,
[0053] FIG. 6 shows the dependency of various components of the magnetic flux density on the revolution angle for a magnetic quadrupole, and
[0054] FIG. 7 shows a schematic illustration of a mine-sweeping system according to a second example of the invention.
DETAILED DESCRIPTION OF INVENTION
[0055] In the figures, identical or functionally identical elements are provided with the same reference signs.
[0056] FIG. 1 shows a schematic illustration of a magnetic signature 1 of a ship which has a longitudinal extent in the region of approximately 200 m. This magnetic signature is intended to be reproduced as accurately in every detail as possible by a mine-sweeping system in order therefore, for a modern complex sea mine, to simulate the passing by of a corresponding ship and thus to bring the sea mine to detonate. FIG. 1 illustrates the dependency of the magnitude of the magnetic flux density B on the position of an observation point, for example below the ship. Accordingly, the horizontal distance d of the observation point from the center of gravity of the ship is illustrated in meters on the abscissa. This therefore involves a position-dependent magnetic signature 1. By way of example, only the magnitude of the magnetic flux density is illustrated in FIG. 1. Corresponding additional curves arise analogously if, depending on the horizontal distance, the individual direction components (for example in the Cartesian directions in space x, y and z) of the magnetic flux density are taken into consideration. Modern complex sea mines are frequently configured to compare a measured profile of the magnitude of the magnetic flux density and also of the individual direction components thereof with the known magnetic signatures of predefined types of ship and to detonate only if there is a sufficiently high correspondence.
[0057] In the following, a magnetic signature is understood as meaning in general the dependency of the magnetic flux density on a position coordinate as is illustrated in FIG. 1. Since, however, a sea mine is not spatially extended, it can measure the detected magnetic parameter not as a function of the location, but only as a function of the time. This time dependency is calculated from the positional dependency, shown in FIG. 1, of a magnetic parameter in combination with the speed of the passing ship and the (shortest) distance at which the ship passes the stationary sea mine. The sea mine therefore actually measures a time-dependent magnetic profile which is produced as a function of the magnetic signature outlined in FIG. 1. The task of a mine-sweeping system is therefore to simulate the corresponding time-dependent magnetic profile of such a passing ship as well as possible, specifically ideally not only for the magnitude of the magnetic flux density B that is illustrated in FIG. 1, but simultaneously also for one or more direction components. Complex characteristic patterns for certain defined types of ship can be produced in this case.
[0058] FIG. 2 shows a schematic partially perspective sectional illustration of a mine-sweeping system 21 according to a first example of the invention. In the example shown, this mine-sweeping system 21 comprises only a single drone 22 which here is diving in the water 20 and below the water surface 29, specifically with a diving depth T. Alternatively or additionally, however, a use floating on the water surface also comes into consideration. The drone 21 has a central longitudinal axis A and moves along a travel direction v which coincides here with the longitudinal axis A.
[0059] The drone 22 is a self-driven drone which can itself be moved in the water by means of an electric motor 23 and a propeller 24 mechanically coupled thereto, and does not have to be towed by a mother ship. Alternatively, however, an embodiment with only a passive towing drive is also conceivable. The drone 22 is configured to generate, at a target location 26, a time-dependent magnetic profile which corresponds as exactly as possible to the magnetic profile which a ship traveling past at a typical travel speed and having a specified magnetic signature would generate. In other words, the intention is to simulate the magnetic signature of a known type of ship in order to bring a sea mine positioned at the target location 26 to detonation.
[0060] In order to generate the desired time-dependent magnetic profile at the target location 26, the drone 22 is equipped with at least one magnet element. Only by way of example are a plurality of different magnet elements shown for the drone 22 in FIG. 2: this drone thus has firstly a plurality of coil elements 27a which are used as excitation coils of the electric motor 23. However, these coil elements 27a carry out a dual function and serve at the same time to contribute to the generation of the desired magnetic profile at the target location 26. In addition, in the rear part of the drone 22, further coil elements 27b are shown which likewise contribute to the generation of the desired magnetic profile, but are not part of the electric motor. Of the two types of coil 27a and 27b, there can be in each case one or more in such a drone. It is particularly advantageous if the individual coil elements can be fed with a variable current such that the amplitude of the generated magnetic field can be additionally modulated. In the front region, the drone 22 additionally has a permanent magnet 28 which is illustrated here by way of example as an annular disk magnet. In principle, however, such permanent magnets can be present in the drone in any form and also in any number. Such permanent magnets can also contribute to the generation of the desired magnetic profile. However, the arrangement of the individual different types of magnet elements 27a, 27b and 28 within a drone should be understood here as merely being by way of example. Although a plurality of such elements may be arranged within a drone, it is, however, generally sufficient if a drone comprises at least one magnetic element in order to bring about a magnetic detonation of a sea mine.
[0061] In the example of FIG. 2, the current direction of travel v of the drone is coaxial with the longitudinal axis A. In principle, however, the translational movement of the drone may also have different direction components. In FIG. 2, the direction of travel v is slightly oblique in the coordinate system shown (with the Cartesian direction coordinates x, y and z). The direction of travel v does indeed have a relatively large horizontal direction component within the xy plane which lies parallel to the water surface. However, it additionally also has a slight component in the z direction which corresponds here to a slight sinking of the drone.
[0062] In addition to this translational movement, the drone, however, also executes at least one rotation movement with respect to at least one degree of rotational freedom. The three independent degrees of rotational freedom of the drone are denoted by the arrows r1, r2 and r3 in FIG. 2. In this case, the degree of rotational freedom r1 corresponds to rolling or heeling of the drone, the degree of rotational freedom r2 corresponds to pitching or trimming, and the degree of rotational freedom r3 corresponds to yawing or rotating. A complex rotational movement may also take place in which the drone is rotated about a plurality of the aforementioned degrees of rotational freedom. In each case, the described rotation of the drone modulates the magnetic flux density generated at a certain time at the target location 26. This relates in general both to the magnitude and to the individual direction components of the flux density. The rotational movement can therefore be used in order, at the target location 26, to reproduce the time-dependent magnetic profile, which is intended to correspond to the magnetic signature of a passing ship, as accurately as possible. In order to improve the reproduction of the desired magnetic profile even further, the described rotational movement can optionally be combined with a variation of the diving depth T and/or with a variation of the operating current of the coil element 27a or 28a and/or with a variation of direction of travel v and/or travel speed.
[0063] It is generally particularly effective if, during the travel of the drone 22 through the water, at least the described rotation movement is carried out multiple times successively. It can therefore be achieved that a desired magnetic profile is reproduced successively at different target locations 26. This is true irrespective of whether the rotational movement, which is carried out, is carried out in each case simultaneously with the translational forward movement or in an alternating manner with the translational forward movement of the drone.
[0064] It is particularly advantageous if the rotational movement of the drone is at least a rotational movement with respect to the first degree of rotational freedom r1, in other words if it comprises rolling or heeling of the drone. In order to permit such rolling, the drone 22 of FIG. 2 is provided with a control element 25. This can be either an active control element (for example an electric motor) or else a passive control element (for example a rudder or a flap). Corresponding further control elements, not illustrated specifically here, can also be provided for the rotational movement with respect to the other degrees of rotational freedom r2 and/or r3.
[0065] The mine detonation by the described mine-sweeping system 21 is particularly effective if, at the target location 26, a comparatively high magnetic flux density in comparison to the other environment of the drone is generated, wherein said target location 26 can still lie upstream of the drone, as seen in the direction of travel v. Particularly advantageously, it can lie upstream of the drone, as shown in the direction of travel in FIG. 2, and below the drone with respect to the water surface. The desired magnetic profile can in each case be projected ahead to said target location and sea mines arranged at the target location can already be brought to detonation at a certain distance from the drone passing by, which reduces the risk of damage to the drone during detonation.
[0066] It is intended to be clarified with the following FIGS. 3 to 6 how the described rotational movement of the drone contributes to varying the magnetic field generated at a target location 26 by means of the at least one magnet element. FIG. 3 thus shows an approximately square-shaped rectangular coil 31 as can be used, for example, as coil element 27a or 27b in the drone of FIG. 2. The Cartesian coordinate directions x, y and z shown in FIG. 3 illustrate only a local coordinate system here and are not necessarily intended to correspond to the spatial directions illustrated in FIG. 2. However, the local coordinate system is retained in the following FIGS. 4 and 5. When current flows through the rectangular coil 31, a two-pole magnetic field is generated, the pole axis of which is denoted here by P.
[0067] FIG. 4 shows the simulated three-dimensional profile of the magnetic flux density B formed by the rectangular coil 31 of FIG. 3 when a constant current flow is provided. The profiles are shown for the magnitude of the magnetic flux density, the profiles being produced from the center point Z outward for three different surface sections: a square-shaped cutout of the xy plane, a square-shaped cutout of the xz plane and a square-shaped cutout of the yz plane each having an edge length which corresponds to a multiple of the coil diameter. For this purpose, the corresponding surface cutouts are divided by hatching into regions of similar magnetic flux density, with the division into the value ranges having been selected in accordance with a logarithmic scale. The end points of the value ranges are indicated in arbitrary units, with the numerical values only being intended to clarify that a logarithmic scale has been used. It can readily be seen in FIG. 4 that, for a certain distance from the center, the magnitude of the magnetic flux density B which is formed depends greatly on the spatial orientation of the observation point. By means of a rotational movement of the drone which carries the coil, a significant modulation of the magnetic flux density generated at an outer target location can therefore be achieved. This modulation is particularly powerful if the rotational movement takes place about an axis of rotation which encloses an angle different from 0 with the pole axis P. In other words, the field distribution in the environment changes particularly powerfully if, during the rotation, the magnetic pole axis P itself is tilted.
[0068] FIG. 5 shows the dependency of the magnetic flux density B, formed by the rectangular coil 31 of FIG. 3, on the distance d from the coil center M. This dependency is shown for different directions in space: the curve Bx thus shows the distance dependency for various positions along the x axis. The curve By analogously shows the distance dependency for various positions along the y axis. Finally, the curve Bw shows the distance dependency along the diagonal direction (within the xz plane) which is denoted by w in FIG. 4. The values for the magnitude of the magnetic flux density B are in turn each specified in arbitrary units on a logarithmic scale. The values for the distance d are specified in multiples of the coil diameter. The conspicuous points of the two curves By and Bw mark the locations of the conductors through which current passes. It is shown that, at relatively great distances of a plurality of coil diameters, the magnitudes of the flux densities on the x axis are significantly larger than on the other two axes. It is also shown that, by means of a corresponding rotation of the drone, the magnetic flux density generated at the target location can be powerfully modulated. The direction components (not shown here) can also be correspondingly modulated, with it also being possible to bring about a sign change in the event of a correspondingly high angle of rotation.
[0069] The embodiments in conjunction with FIGS. 3 to 5 apply not only to the coil geometry under consideration here but in a similar manner also for other coil shapes. The powerful direction dependency of the generated magnetic flux density applies in a similar manner also to permanently magnetic dipoles. Even in the case of multi-pole magnet systems, a rotation of the excitation device can bring about a significant modulation of the magnetic flux density generated. This is intended to be clarified by way of example by FIG. 6 for a magnetic quadrupole arrangement: FIG. 6 thus shows the dependency of various components of the magnetic flux density on the revolution angle 63 for a magnetic quadrupole which can be realized, for example, by a symmetrical arrangement of four electrical coil elements. The upper part of FIG. 6 shows how the magnitude of the magnetic flux density 61 (here in arbitrary units) varies over a half revolution of 180° about the quadrupole arrangement. This revolution has been simulated with a constant radius. The magnetic flux density 61 here in each case reaches a maximum in the region of the two magnetic pole axes P1 and P2 while it decreases by a significant factor in the regions in between.
[0070] It is shown in the lower part of FIG. 6 how the direction components 62 of the magnetic flux density vary during a corresponding revolution. The values for the direction components 62 are also specified here in arbitrary units. The curve Br denotes the profile of the local radial direction component, while the curve Bt shows the profile of the local tangential direction component. As seen over the half revolution of 180°, powerful modulations each having two zero crossings are produced for the two curves. Therefore, via corresponding rotation of a drone with a magnetic quadrupole, a powerful modulation can be achieved both for the magnitude of the magnetic flux density and for the individual direction components. In particular, a specified complex profile of the individual direction components can be reproduced.
[0071] If, therefore, the sea mine which is to be detonated carries out a comparison with a stored desired profile not only for the magnitude of the magnetic flux density, but also for the individual direction components thereof, then, by means of a suitable sequence of rotational movements of the drone, the desired magnetic profile can nevertheless be substantially reproduced.
[0072] FIG. 7 finally shows a schematic illustration of a mine-sweeping system 21 according to a further example of the invention. The mine-sweeping system illustrated here has a guiding drone 22 which can be constructed, for example, similarly to the drone 22 of FIG. 2. In particular, said guiding drone 22 can be a self-driven drone and can carry out similar translational movements and rotational movements as the drone of FIG. 2. In addition, the mine-sweeping system 21 of FIG. 7 also has two further drones 71 which are connected to the guiding drone 22 by a towing cable 72. This multi-sectional mine-sweeping system is also configured overall for forming a predefined magnetic profile at a target location 26. For this purpose, each of the drones 22 and 71 has at least one magnet element. The two rear drones 71 are also designed to in each case carry out rotational movements independently of one another with respect to at least one degree of rotational freedom. By means of this plurality of rotatably designed drones 22 and 71, the desired magnetic profile can be modulated even more accurately in detail at the target location 26. The outlay on apparatus (i.e. in particular the number of drones and/or the spatial extent of the chain) can advantageously be kept smaller here than in the prior art because of the use of the rotational movements.
LIST OF REFERENCE SIGNS
[0073] 1 Magnetic signature [0074] 20 Water [0075] 21 Mine-sweeping system [0076] 22 Drone [0077] 23 Electric motor [0078] 24 Propeller [0079] 25 Control element [0080] 26 Target location [0081] 27a Coil element [0082] 27b Coil element [0083] 28 Permanent magnet [0084] 29 Water surface [0085] 31 Rectangular coil [0086] 61 Magnitude of the magnetic flux density [0087] 62 Magnetic flux density [0088] 63 Revolution angle in degrees [0089] 71 Drone [0090] 72 Towing cable [0091] A Longitudinal axis [0092] B Magnetic flux density [0093] Br Radial component of the magnetic flux density [0094] Bt Tangential component of the magnetic flux density [0095] Bx Profile of the flux density along the x axis [0096] By Profile of the flux density along the y axis [0097] Bw Profile of the flux density along the direction w [0098] d Distance from the center of gravity [0099] M Center point of the coil element [0100] P Pole axis [0101] P1 First pole axis [0102] P2 Second pole axis [0103] r1 First degree of rotational freedom [0104] r2 Second degree of rotational freedom [0105] r3 Third degree of rotational freedom [0106] T Diving depth [0107] v Direction of travel [0108] w Diagonal direction in space in yz plane [0109] x,y,z Cartesian directions in space
