Towing device, recovery device and system for recovering a cable-based, unmanned underwater vehicle from the water

Abstract

A pulling device (28) for recovering a cable-based, unmanned underwater vehicle (22) from the water onto a platform and / or lowering the underwater vehicle from the platform into the water is disclosed. The pulling device (28) comprises a pulling means (32, 32') and a holding element (50a, 50b). The pulling means (32, 32') is designed to be connected to the underwater vehicle (22) and is designed to absorb a force for recovering the underwater vehicle from the water. The holding element (50) is connected to the pulling means (32, 32'), wherein the holding element (50a, 50b) is designed to be gripped by a lifting device (36) in order to recover the underwater vehicle (22) from the water. Furthermore, the holding element (50a, 50b) has an opening designed to receive the cable (34) with low tensile stress. Optionally, a plurality of spacers (52) are arranged between the first holding element (50a) and the underwater vehicle (22).Optionally, the holding elements (50a, 50b) each have two projections (51) with which the holding elements (50a, 50b) can engage in corresponding cavities of the lifting device (36). Optionally, the lifting device (36) is designed as a driven wheel. The wheel has a plurality of cavities (54) into which the projections (51) of the holding elements (50a, 50b) can engage. Furthermore, a recovery device comprising the pulling device (28) is disclosed, wherein the recovery device optionally has an alignment element (44).

Description

[0001] The invention relates to a pulling device, a recovery device and a system for recovering a cable-based, unmanned underwater vehicle from the water onto a platform.

[0002] The recovery of underwater vehicles connected to a base platform, such as a surface vessel such as a ship, by a cable, particularly a fiber optic cable, poses a significant risk to the cable. The cable is permanently connected to the platform but is not designed to withstand significant tensile forces. In particular, the unmanned underwater vehicle cannot be lifted out of the water using the cable without tearing. Making the cable thicker and thus more tear-resistant along its entire length is not a good option, as this would lead to undesirable hydrodynamic effects.Attempts to armour the cable only directly on the underwater vehicle and thus make it more resistant for the actual recovery process often fail because excessive tensile forces are exerted on the non-armoured cable section at the transition point, which can cause the cable to tear, or because a thickening is required at the transition point, which cannot be reeled up by the winch system.

[0003] US 9 828 068 B2 discloses a mechanical cable system for an underwater vehicle.

[0004] DE 20 2004 018 166 U1 discloses a device for deploying and / or retrieving an underwater vehicle.

[0005] The object of the present invention is therefore to create an improved concept for the recovery of cable-based underwater vehicles.

[0006] This object is achieved by the subject matter of the independent patent claims. Further advantageous embodiments are the subject matter of the dependent patent claims.

[0007] Embodiments show a traction device for recovering a cable-connected, unmanned underwater vehicle from the water onto a platform. The traction device comprises a traction means, in particular two or more parallel traction means. A rope or a belt, for example, can be used as the traction means. The traction means is (mechanically) connected to the underwater vehicle and designed to absorb a force resulting from the recovery of the underwater vehicle from the water. This means that the underwater vehicle can be lifted from the water in a freely suspended manner using the traction means(s).

[0008] The traction device further comprises a holding element, preferably a plurality of holding elements, which is (mechanically) connected to the traction means. The holding element is designed to be gripped by a lifting device in order to recover the underwater vehicle from the water. This means that the connection between the traction means and the holding element is so strong that the underwater vehicle can be lifted out of the water while freely suspended by the holding element. Suitable lifting devices include, for example, driven gears or V-belts with circumferential grooves into which the holding element can engage.

[0009] The retaining element has an opening, in particular a completely enclosed opening, designed to accommodate the cable with minimal tensile stress. In particular, apart from the usual friction between two materials, the opening should not exert any tensile force on the cable when the cable moves longitudinally relative to the retaining element.

[0010] The idea is to run a traction device parallel to the cable, with the cable and traction device arranged so that they can move relative to each other. Due to the movable arrangement relative to each other, the traction device cannot exert any tension on the cable, thus eliminating the risk of the cable breaking. Nevertheless, the underwater vehicle can be pulled out of the water and lowered into the water using holding elements arranged on the traction device. The holding element also ensures that the cable and traction device do not become tangled or twisted due to rotation of the underwater vehicle, thus also preventing any such external tension on the cable.

[0011] In exemplary embodiments, a spacer is arranged between the holding element and the underwater vehicle. The spacer is designed to tighten the traction means so that the holding element is held at a distance from the underwater vehicle. The spacer makes it possible for the traction means not to need to be continuously connected to the platform. This means that the holding element is permanently spaced from the underwater vehicle so that the lifting device can grip the holding element. In particular, the holding element is then also carried along with the cable. For example, using the spacer, the holding element is pulled out of the water and onto the platform or to the lifting element when the cable is retrieved. If the traction means does not need to be permanently connected to the platform, this means that the traction device can be significantly shorter than the cable.The shorter the towing device, the lower the hydrodynamic influences, such as the drag of the towing device in the water, resulting in minimal impairment of the maneuverability of the underwater vehicle. Furthermore, a short towing device requires less material and is easier to install, thus reducing costs, the required storage space on the platform, and the weight. For standard vessels, a towing device length of a maximum of 25 m, a maximum of 12 m, or preferably a maximum of 6 m is sufficient.

[0012] When selecting the length of the towing device, a balance must be struck between the additional weight and disturbing influence on the one hand and the maximum height above the water surface of the lifting device with which the underwater vehicle can be retrieved.

[0013] The length of the towing device should preferably be selected to be at least the same length as the distance between the receptacle for the holding element in the lifting device and the water surface. The length of the towing device can be determined as the distance between the holding element, or in the case of a plurality of holding elements, the first holding element, and the underwater vehicle. The length is then determined with the towing device stretched out. Typically, depending on the design of the platform, this can be at least 3 m, at least 5 m or at least 10 m. A buffer is preferably planned here to compensate for, for example, sea state and tides or different drafts in different loading situations if the platform is a floating platform.

[0014] In embodiments, the spacer is designed to be bent. This is advantageous because the spacer can thus follow a curvature of the traction means. For example, the traction means is curved when the underwater vehicle lies horizontally in the water while the holding element is pulled vertically upwards. Furthermore, the traction means is curved when it is guided over a deflection pulley or wound onto a winch, e.g. on the platform. Additionally or alternatively, the same effect can be achieved by the holding element being one of a plurality of holding elements, wherein the holding elements are arranged so as to be movable relative to one another. Thus, the spacers can move against one another, similar to a scale armor, and enable a curvature of the traction means.

[0015] This embodiment can preferably be used when a plurality of holding elements are arranged on the traction means and one or more spacers are arranged between each holding element. It is also advantageous if the spacers, in contrast to the holding element(s), are not fixed but rather movable on the traction means. This makes it possible for the spacers to also move relative to the holding element(s). This facilitates the curvature of the traction means, particularly when a plurality of spacers are arranged between two adjacent holding elements or between the holding element and the underwater vehicle. In other words, the scale armor effect described above is simplified.

[0016] Furthermore, the flexibility of the entire towing device is not only advantageous when launching and recovering the underwater vehicle, but also improves the maneuverability of the underwater vehicle during its mission.

[0017] In further embodiments, the spacers are designed such that the entire traction device is essentially buoyancy-neutral in the water. This means, for example, that the number and density of the material of the spacers can be selected such that the resulting density of the traction device essentially corresponds to the density of the water. In another consideration, a material is selected for the spacers that generates buoyancy in the water. The volume and number of spacers are then selected such that the traction device is essentially buoyancy-neutral. Essentially means that there can of course be slight deviations. For example, the density of the water depends on the salt content and the temperature of the water. The buoyancy of the spacers can therefore change even during a maneuver. Furthermore, manufacturing tolerances and any tolerable deviations must be taken into account with regard to cost optimization.

[0018] In further embodiments, the holding element has a projection on both sides of the opening, which is designed to engage a cavity provided for this purpose in the lifting device. For example, the lifting device is arranged on the platform in such a way that the two projections are guided into the cavity of the lifting device when the cable is pulled in. This makes it possible to reliably grip the holding element. Any catching of the holding element in the water is not necessary.

[0019] Further embodiments show a recovery device for recovering the cable-based, unmanned underwater vehicle from the water onto a platform using the pulling device. Additionally, the recovery device comprises the lifting device, which is configured to grip the holding element and recover the underwater vehicle using the holding element.

[0020] In exemplary embodiments, the recovery device comprises a winch configured to wind and unwind the cable, in particular an optical fiber cable. The winch can therefore take over the cable guidance, particularly during a mission of the underwater vehicle. Furthermore, by winding up the cable, the winch can guide the (first) holding element to the lifting device.

[0021] In further embodiments, the lifting device (36) comprises a driven wheel, wherein the wheel has an (annular) circumferential groove in which the traction means and the cable are guided and wherein the wheel has a plurality of cavities into which the holding element engages, such that the wheel is designed to move the holding element in accordance with the direction of rotation of the wheel. The drive principle can be compared to a toothed belt drive. There, too, teeth (holding element or projections thereof) engage in a corresponding cavity. It should be noted, however, that a closed belt is used for a toothed belt drive, whereas the traction device is moved and possibly deflected via the lifting device presented here, but is not closed in itself.

[0022] To return to the example of the toothed belt drive with regard to the retaining element with projections arranged on both sides of the opening, such a wheel can be provided with a circumferential groove in which the cable can be guided freely. In particular, the wheel should not exert any tensile stress on the cable that exceeds normal friction.

[0023] Further embodiments show the retrieval device with an alignment element configured to align the holding element such that the lifting device can grip the holding element. Particularly in the embodiments in which the holding element has one or more projections, the projections can be rotated by the alignment element such that the projection(s) can engage the corresponding cavities.

[0024] Furthermore, a system with the pulling device or the recovery device as well as the underwater vehicle and / or the platform, in particular a surface vehicle as a platform, is disclosed.

[0025] Preferred embodiments of the present invention are explained below with reference to the accompanying drawings. Fig. 1: a schematic side view of a system for recovering and / or deploying a cable-based unmanned underwater vehicle while the underwater vehicle is in the water, wherein a pulling device is arranged parallel to the cable in a section extending from the underwater vehicle; Fig. 2: a schematic side view of the system from Fig. 1, wherein the underwater vehicle is in a recovery position and a lifting device engages a first holding element of the pulling device to pull the underwater vehicle out of the water; Fig. 3: a schematic side view of the system from Fig. 1 and Fig. 2, wherein the underwater vehicle is suspended in the air from the lifting device; Fig. 4: a schematic side view of the system from Fig. 1, Fig. 2 and Fig. 3, wherein the lifting device is folded to save space; Fig. 5: a schematic, more detailed representation of a recovery device of the system, where Fig. 5a an overview in side view, Fig. 5b a holding element in plan view, Fig. 5c and Fig. 5d each shows a wheel as a lifting device in a schematic perspective view in different embodiments and Fig. 5e discloses an alignment element in a schematic perspective view.

[0026] Before exemplary embodiments of the present invention are explained in more detail below with reference to the drawings, it is pointed out that identical, functionally identical or equivalent elements, objects and / or structures in the different figures are provided with the same reference numerals, so that the description of these elements shown in different exemplary embodiments is interchangeable or can be applied to one another.

[0027] Fig. 1 shows a schematic side view of a system 20 for recovering a cable-based, unmanned underwater vehicle 22 from the water 24 onto a platform 26 and / or lowering the underwater vehicle 22 from the platform 26 into the water 24 by means of a recovery device 30 comprising a pulling device 28 and a lifting device 36. The pulling device 28 comprises a pulling means 32 (cf. Fig. 5), which is firmly connected to the underwater vehicle 22. The pulling device 28 is shown with a broken edge 29 to indicate that the pulling device 28 is longer than shown. The cable 34, with which the underwater vehicle 22 is remotely controlled, runs through the pulling device 28. The cable 34 runs over a lifting device 36 in order to be able to pull the underwater vehicle 22 out of the water 24 by means of the pulling device 28 or to lower the underwater vehicle 22 into the water 24. The lifting device 36 is shown as a driven roller. Furthermore, the lifting device 36 is arranged on a crane 38, wherein the lifting device 36 is connected to the platform 26 by means of the crane 38. The cable 34 is also guided over the lifting device 36. The cable management is operated by means of a winch 40 during the mission of the underwater vehicle 22. This means that the winch 40 can wind up and unwind the cable 34.

[0028] Fig. 2 shows a schematic side view of the system 20, wherein the winch 40 has wound up the cable 34 so far that the lifting device 36 can pull the traction means 28 (or a first holding element arranged on the traction means - see Fig. 5) can take hold.

[0029] Fig. Figure 3 shows a schematic side view of the system 20, with the lifting device 36 having pulled the underwater vehicle 22 out of the water 24 using the pulling device 28. The winch 40 guides the cable 34 loosely, i.e., without significant tension. The force for supporting the underwater vehicle 22 is applied by the lifting device 36.

[0030] Fig. 4 shows a schematic side view of the system 20, wherein the crane 38 is folded together with the underwater vehicle 22 on the platform 26 to save space.

[0031] It should be noted that the figures only disclose an exemplary embodiment. In particular, the design of the crane 38, the platform 26, the cable guide 34, and the lifting device 36 may vary.

[0032] Fig. Figure 5a shows an overview of a recovery device 30 in a side view. The recovery device 30 comprises the pulling device 28 and the lifting device 36. Furthermore, the recovery device 30 optionally comprises an alignment element 44.

[0033] The traction device 28 comprises a first traction means 32 and an optional second traction means 32'. The traction means 32 and 32' are firmly connected to the underwater vehicle 22. Furthermore, the traction device 28 comprises a plurality of holding elements 50 (six holding elements are shown here as an example). The holding elements 50 each have two projections 51, with which the holding elements 50 can engage in corresponding cavities of the lifting device 36.

[0034] Optionally, a plurality of spacers 52 are arranged between the first holding element 50a, i.e. the holding element closest to the lifting device, and the underwater vehicle 22. This includes that at least one spacer 52, in particular a plurality of spacers 52, is arranged between the holding elements 50 and between the last holding element 50b, i.e. the holding element closest to the underwater vehicle 22, and the underwater vehicle 22. The spacer(s) 52 prevent, for example, the pulling device from collapsing, i.e. that the holding elements 50 slide down the cable and together form a stack that rests on the stern of the underwater vehicle. In other words, the spacers 50 tighten the pulling means. By way of example, three spacers are used, but typically further gaps would be filled with additional spacers.However, it is advantageous that the number of spacers is selected such that they are movable relative to one another and relative to the retaining elements. This means that the retaining elements are arranged movably on the traction means(s) 32, 32' and movably on the cable 34. This makes it possible to bend the traction device 28.

[0035] In further advantageous embodiments, a material is selected for the spacers 52 that generates buoyancy in the water 24. The volume and number of spacers 52 are then selected such that the traction device 28 as a whole is essentially buoyancy-neutral.

[0036] The lifting device 36 is designed, for example, as a driven wheel, although the drive is not shown for reasons of clarity. The wheel has a plurality of cavities 54 into which the projections 51 of the holding elements 50 can engage. To guide the cable and the central part of the holding elements and the traction means(s), the wheel also has a circumferential groove 56. With projections arranged on both sides of the holding elements 50, the groove runs centrally between the cavities 54. This means that the groove 56 runs between two bands of cavities running around the wheel, so that the bands of cavities are each designed to receive a projection 51 of the holding element 50 in order to move the holding element in accordance with the direction of movement of the lifting device 36.

[0037] Fig. 5b shows a schematic perspective detailed view of the holding element 50 in a plan view (during Fig. 5a shows a side view). Shown is an opening 55 for the first traction means and optionally a further opening 55' for the second traction means. A pin is shown within the openings as an example, indicating that the traction means are firmly clamped in the opening 55 or the further opening 55'. Furthermore, the holding element has an opening 57 for guiding the cable. The cable is guided through this opening with little tensile stress, i.e., loosely.

[0038] Fig. 5c and Fig. 5d show a schematic perspective detailed view of the lifting device 36 in various embodiments. The lifting device 36 is, as already described with regard to Fig. 5a, is designed, for example, as a wheel driven by a drive 58. Bands of cavities 54 are arranged on both sides of the groove 56, into which the projections of the holding elements can engage. The arrangement of the bands of the cavities 54 is shown in Fig. 5c inside and in Fig. 5d arranged externally.

[0039] Fig.5e shows a schematic, perspective detailed view of the optional alignment element 44. This has two, for example helical, ramps 60, onto which a projection of the holding element strikes if the latter is not oriented such that it can engage with the cavities of the lifting device. This can occur, for example, in the event of torsion of the traction device, in particular of the traction means(s). If the projection is correctly aligned, either because it has been aligned by the ramps or because it was originally already correctly aligned, the projection runs through an opening 62 between the two ramps. The ramps are preferably arranged in an approximately semicircular manner. Optionally, a second pair of ramps (not shown) is arranged mirror-symmetrically to the illustrated ramps in order to also guide the second projection on the holding element.This isn't necessary, as the second protrusion automatically moves into position when the first protrusion is properly positioned. However, it does reduce the risk of the retaining element slipping out of the alignment element without the protrusion being aligned.

[0040] Although some aspects have been described in connection with a device, it should be understood that these aspects also represent a description of the corresponding method, so that a block or component of a device can also be understood as a corresponding method step or as a feature of a method step. Analogously, aspects described in connection with or as a method step also represent a description of a corresponding block, detail, or feature of a corresponding device.

[0041] The above-described embodiments are merely illustrative of the principles of the present invention. It is understood that modifications and variations of the arrangements and details described herein will be apparent to others skilled in the art. Therefore, it is intended that the invention be limited only by the scope of the following claims and not by the specific details presented in the description and explanation of the embodiments herein. List of reference symbols: 20 systems 22 tethered unmanned underwater vehicle 24 Water 26 Platform 28 Towing device 29 Break edge 30 rescue device 32, 32' traction device 34 cables 36 Lifting device 38 crane 40 winds 44 Alignment element 50 holding element 51 lead 52 spacers 54 Cavity 55, 55' opening 56 grooves 57 Opening with retaining pin 58 Drive 60 Ramp 62 Breakthrough

Claims

[1] Towing device (28) for recovering a cable-based, unmanned underwater vehicle (22) from the water (24) onto a platform (26) and / or lowering the underwater vehicle (22) from the platform (26) into the water (24), having the following features: - a traction means (32) which is designed to be connected to the underwater vehicle (22) and which is designed to absorb a force for recovering the underwater vehicle (22) from the water (24); characterized by following features: - a holding element (50) connected to the traction means (32), wherein the holding element (50) is designed to be gripped by a lifting device (36) in order to recover the underwater vehicle (22) from the water (24); - wherein the holding element (50) has an opening (57) which is designed to receive the cable (34) with low tensile stress. [2] Traction device (28) according to claim 1, wherein a spacer (52) is arranged between the holding element (50) and the underwater vehicle (22), wherein the spacer (52) is designed to tighten the traction means (32) so that the holding element (50) is held at a distance from the underwater vehicle (22). [3] The pulling device (28) according to claim 2, wherein the spacer (52) is configured to be bent. [4] A pulling device (28) according to any one of claims 2 or 3, wherein the spacer (52) is one spacer (52) of a plurality of spacers (52), wherein the spacers (52) of the plurality of spacers (52) are arranged to be movable relative to one another. [5] A traction device (28) according to claim 4, wherein the spacers of the plurality of spacers are configured such that the entire traction device is substantially buoyancy-neutral in the water (24). [6] Traction device (28) according to one of the preceding claims, wherein the traction device (28) has a maximum length of 25 m. [7] Pulling device (28) according to one of the preceding claims, wherein the holding element (50) has a projection (51) on both sides of the opening (57) which is designed to engage in a cavity (54) of the lifting device (36) provided for this purpose. [8] Recovery device (30) for recovering a cable-connected, unmanned underwater vehicle (22) from the water (24) onto a platform (26) and lowering the underwater vehicle (22) from the platform (26) into the water (24), having the following features: - the pulling device (28) according to one of the preceding claims; - the lifting device (36), wherein the lifting device (36) is designed to grip the holding element (50) and to recover the underwater vehicle (22) on the holding element (50). [9] Recovery device (30) according to claim 8, comprising a winch (40) which is designed to wind up and / or unwind the cable (34), in particular an optical fiber as the cable (34). [10] Recovery device (30) according to one of claims 8 or 9, comprising a driven wheel as a lifting device (36), wherein the wheel has a circumferential groove (56) in which the traction means (32) and the cable (34) are guided and wherein the wheel has a plurality of cavities (54) into which the holding element (50) engages, so that the wheel is designed to move the holding element (50) according to the direction of rotation of the wheel. [11] Recovery device (30) according to claim 10, - wherein the holding element (50) has a projection (51) on both sides of the opening (57); - wherein the groove (56) extends between two bands of cavities (54) running around the wheel, so that the bands of cavities (54) are each designed to receive a projection (51) of the holding element (50) in order to move the holding element (50) in accordance with the direction of rotation of the wheel. [12] Recovery device (30) according to one of claims 8 to 11, comprising an alignment element (44) which is designed to align the holding element (50) such that the lifting device (36) can grip the holding element (50). [13] Recovery device (30) according to one of claims 8 to 12, wherein the length of the pulling device (28) is selected to be at least long enough to bridge the distance between the water surface and the lifting device (36). [14] System (20) comprising - the pulling device (28) according to one of claims 1 to 7 or the recovery device (30) according to one of claims 8 to 13; and - the tethered unmanned underwater vehicle (22) and / or the platform (26).

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