WO2000071415A1 - Docking device for self-propelled autonomous underwater vehicles - Google Patents

Abstract

A docking device (1) for self-propelled autonomous underwater vehicles (2) is substantially constituted by a closable cage-like frame (3) which has means for acquiring data and transmitting energy form and to the vehicles and means for centering, alignment and temporary locking of the self-propelled vehicles.

Description

DOCKING DEVICE FOR SELF-PROPELLED AUTONOMOUS UNDERWATER VEHICLES TECHNICAL FIELD

The present invention relates to a docking device for self-propelled autonomous underwater vehicles. BACKGROUND ART

Nowadays it is known to use autonomous underwater vehicles, also known as AUV, which are substantially constituted by an enclosure which has high-level hydrodynamic characteristics, and therefore is for example torpedo-shaped, and has its own propulsion system and suitable dedicated devices for its remote control; these vehicles are used for many purposes, such as underwater searches, inspections, and monitoring of natural or artificial infrastructures.

However, these autonomous underwater vehicles have a limited operating capability in terms of time, since they require periodic replenishment of the energy that can be stored in them for propulsion and for operating the various internal devices as well as for downloading the data acquired during their use.

US-5,349,916 is also known which discloses a vehicle which is connected, by means of a first cable, to a submarine; said vehicle can couple at an adapted underwater buoy which is substantially constituted by a base element, arranged on the seabed, from which a cable extends; at its other end, said cable is fixed to a float which is provided, for example, with a sonar beacon which allows the approach of the vehicle, since said vehicle is provided with a corresponding sonar detector.

The underwater vehicle has a device which is located in its front part and is shaped like a V in which the vertex starts from the nose of the vehicle; this shape allows to facilitate docking to the buoy.

It is also known to use docking stations which are anchored to the bottom of the ocean and are connected, for example, to an adapted buoy provided with means for satellite or cable communication, as disclosed in US- 5,291,194, with a remote station.

These conventional docking stations are therefore constituted by a combination of mechanical and electronic devices which allow the underwater vehicle to approach from any direction, at the same time allowing to transfer data from said vehicle and, for example, to recharge its batteries.

In order to improve the docking of the underwater vehicle, the various conventional docking stations also include solutions which include a cable which is interposed between two adapted carriages and to which the front part or nose of the vehicle connects by way of an openable engagement means, allowing vertical sliding of the vehicle or of the two carriages, one carriage moving in an upward direction, until the entire vehicle or part thereof is enclosed. Once engagement has occurred, the two carriages move mutually closer so as to lock the vehicle and prevent its accidental disengagement.

A basic problem that can be noted in the prior art is in fact constituted by the difficulty to maintain a stable connection of the vehicle so as to allow its subsequent maintenance at the end of the mission. One solution to the connection of the vehicle, shown in US-5,291,194, uses a conical element which enters a complementarily shaped seat formed in the dorsal region of the vehicle; this solution is not free from drawbacks, such as possible jamming of the sliding of the cable or failed insertion of the conical element in the seat. It is also known to use an autonomous underwater vehicle known as

REMUS (acronym of Remote Environmental Monitoring Unit) which uses, in order to allow easier transfer of the vehicle from the deck of the ship to the sea and vice versa, a fixed cage-like frame which is substantially cylindrical and in which one end is closed and the other one is open for the insertion of the vehicle, the insertion being facilitated by a metallic guiding structure which has a conical shape.

This solution, too, has drawbacks, since centering during approach of the vehicle to the structure shaped like a rigid cage is not easy; moreover, the vehicle used is very light, weighing less than 30 kilograms, while a significantly heavy device which can be arranged on the front part or nose of the vehicle is required for its approach to the cage-like structure, and this makes navigation scarcely stable; moreover, this solution entailed, in order to allow the transfer of power to the vehicle, the use of an inductive coupling which has low energy transmission efficiency. Moreover, the use of a rigid cage entails problems as regards possible damage to the vehicle during docking maneuvers, especially because damage can be caused at the front part or nose of the vehicle, which contains instruments.

For example, EP-0 532 096 discloses a machine for engaging a vehicle and lifting it out of the water: this machine, however, is used only to perform surface recovery of the vehicle, which is then subjected to maintenance on the deck of the ship.

This solution is therefore not suited for use for underwater vehicles which receive maintenance underwater. Similar considerations can also be made as regards the subject of US-

3,807,335, which discloses an anchoring system for underwater vehicles which comprises a platform to which the vehicle can dock and which is lowered into the sea from the deck of a ship, so as to allow, by using particular tensioning devices, to support the platform, isolating it from the movement induced by the sea.

DISCLOSURE OF THE INVENTION The aim of the present invention is therefore to solve the cited technical problems, eliminating the drawbacks of the cited prior art, by providing a device which allows to achieve docking for moving autonomous underwater vehicles rapidly and in safety as regards the integrity of said vehicle. Within the scope of this aim, an important object is to provide a docking device which allows to rapidly and easily acquire or transmit data and power with respect to the vehicle.

Another important object is to provide a docking device which can also be used for autonomous underwater vehicles having mutually different dimensions.

This aim, these objects and others which will become better apparent hereinafter are achieved by a docking device for moving autonomous underwater vehicles, characterized in that it is constituted by a closable cage-like frame which has means for acquiring data and transmitting energy from and to said vehicles and means for centering, alignment and temporary locking of said self-propelled vehicles.

BRIEF DESCRIPTION OF THE DRAWINGS Further characteristics and advantages of the present invention will become better apparent from the detailed description of a particular but not exclusive embodiment thereof, illustrated only by way of non-limitative example in the accompanying drawings, wherein:

Figure 1 is a schematic view of a possible use of the docking device; Figure 2 is another view of a second possible use of the docking device; Figure 3 is a side view of the docking device;

Figure 4 is a view, similar to Figure 3, of the docking device with the vehicle associated therewith;

Figures 5 and 6 are front views of the docking device in the open condition and in the condition in which it is closed around the vehicle; Figure 7 is a rear view of the device;

Figures 8, 9, 10 and 11 are views of the step for the docking of the autonomous underwater vehicle until it is arranged in an intended alignment and locking condition;

Figures 12 and 13 are two different views of means used for connection between the vehicle and the data transmission device; Figure 14 is a partially sectional side view of the means for centering the vehicle in the docking device.

WAYS OF CARRYING OUT THE INVENTION With reference to the above-cited figures, the reference numeral 1 designates the docking device particularly for autonomous underwater vehicles, designated by the reference numeral 2.

The docking device 1 is constituted by a closable cage-like frame 3 which can be provided with adapted perimetric guides 4 for adapted first cables 5 which are stretched between a submerged counterweight 6 and a trestle 7 which is rigidly coupled to a deck 8 of a vessel 9.

Second cables 10a, 10b are further slidingly associated along the first cables 5 and are associated, from the deck of the vessel, with the frame 3 for the necessary mechanical and electrical connections.

Alternatively, it is possible to associate with the frame 3 of the device 1, at one end, a first cable 5 which is connected, at its other end, at an adapted articulation 11 which is anchored to a base 12 which can be arranged on the seabed 13.

Second cables 10 for electrical connection to the device 1 are of course provided between the frame 3 and the articulation 11 and are further linked to an adapted land-based station.

Means for keeping the frame 3 of the device 1 in a horizontal position are further associated with the frame and are constituted for example by adapted floats 14, for example of the passive type, as shown in Figure 2.

In the solution shown in Figure 1, instead, suitable collapsible air tanks are associated with the frame 3 of the device 1, are contained within perforated containers 15 and can act as stabilizers supplied by air reserves 32.

The base 12 has a particular shape and is constituted by a body 16 which is substantially shaped like a parallelepiped and has, at one transverse side, a protrusion 17 which is inclined so as to form an acute angle with respect to said transverse side, taking a clockwise rotation as positive.

The shape of said protrusion allows, during the lowering of the base 12 to the seabed, the automatic tipping of said base once it has reached the bottom, since said protrusion axially offsets the vertical axis that passes through the center of gravity of said base.

The frame 3 of the docking device 1 is shaped like a closable cage and is substantially constituted by a plurality of first upper half-frames 18 which are optionally mutually equidistant; each half-frame is substantially C- shaped in a transverse cross-section and is fixed. Two second half-frames 20a, 20b are rotatably freely associated with the ends of the first wings 19 of each first half-frame 18; said second half- frames are substantially L-shaped and have dimensions which form a cagelike structure once the free ends 21a, 21b are arranged mutually adjacent. The movement of the second half-frames 20a, 20b occurs by means of adapted actuators which are constituted for example by pistons 22, whose body is rigidly coupled at a first plate 23 which is rigidly coupled to the first wing 19 of the first half-frame 18 and whose stem is rigidly coupled at a second plate 24 which is rigidly coupled to one of the wings of the second half-frames 20a, 20b. Both the first half-frames and the second half-frames have centering means for the autonomous underwater vehicle 2; said means are preferably constituted by a plurality of contact pads 25 which are constituted by cylindrical bodies 26 which are rigidly coupled, at one end, to suitable third brackets 27 which are rigidly coupled to the first half-frame or to the second half-frame and with which heads 28 are telescopically associated which can slide in contrast with adapted flexible elements.

Preferably, eight contact pads 25 are provided and are arranged in pairs in a radial configuration, so that their heads 28 lie, when the frame is closed, approximately at a curve which corresponds to the external contour of the autonomous underwater vehicle 2. Said contact pads 25 also constitute means for the alignment of the autonomous underwater vehicle 2 once it is arranged inside the frame 3.

Advantageously, the heads 28 of the contact pads 25 have a seat for a ball 29; the head 28 can be allowed to move between two conditions of maximum and minimum protrusion with respect to the cylindrical body.

Advantageously, the flexible element is constituted by a cylindrical helical compression spring 30.

The means for temporarily locking the vehicle are further associated with the frame 3 of the docking device 1 and are constituted by a plurality of bags 31 which can be inflated with water, preferably from the outside environment, or with air or other gas mixture arriving from adapted containers 32.

Advantageously, a first bag and a second bag are arranged adjacent to the inner part of the frame 3 in a region that lies above the dorsal region of the autonomous underwater vehicle 2; a third bag is arranged at a first closed end 33 of said frame, and the prow 34 of the autonomous underwater vehicle 2 interacts with said third bag.

The third bag 31, arranged proximate to the first closed end 33 of the frame 3, cooperates in its actuation with additional means for the alignment and locking of the autonomous underwater vehicle 2; said means are constituted by two wings 35 a, 35b which have a substantially triangular plan shape and are rotatably associated, at mutually parallel and adjacent planes, with a pair of bases 36a, 36b which are rigidly coupled to the frame 3 in a region that lies above the autonomous underwater vehicle, particularly in a region above a dorsal fin 37 thereof.

At rest, the wings 35a and 35b are arranged so that their tips are mutually opposite: when the autonomous underwater vehicle enters the frame 3, the fin 37 interacts by abutment with the wings 35a and 35b, forcing them to rotate so as to move mutually apart until the fin 37 can pass beyond them toward the first closed end 33 of the frame 3; this situation is shown in Figures 8 and 9.

The arrangement of the bases 36a and 36b and the shape of the third bag 31 rigidly coupled to the first closed end 33 of the frame 3 are such that the passage of the fin beyond the wings 35a and 35b corresponds to the resting of the nose 34 of the vehicle at the third bag 31; said bag, due to the inertia of the vehicle, expels the water contained therein through adapted venting valves and then, by pumping ambient water, expands and pushes the vehicle backward.

In the meantime, the wings 35a and 35b have returned to the initial condition, for example by using the flexible elements provided for this purpose; in this position they cannot rotate so that their vertices move away from the first closed end 33 of the frame 3.

In its backward movement, therefore, the vehicle makes contact, with the vertical dorsal region 28 of the fin 37, at the wings 35a and 35b, which lock it, preventing its movement and ensuring that the vehicle lies in an exact position with respect to the frame 3.

Advantageously, it is possible to provide mechanical guides for the correct alignment of the fin 37 in the interspace between the wings 35a and 35b and therefore, for example, by means of adapted inclined walls. The third bag 31, which interacts with the nose of the vehicle, can of course be connected to adapted pumping elements in order to vary its volume according to specific requirements.

The described means therefore allow, for example, to arrange a device, which is designated by the reference numeral 39, is provided on the frame 3 and is meant to recharge the batteries of the vehicle and to download or upload data from or to said vehicle, at a suitable cavity 40 formed therein.

The device 39 can therefore be constituted by an arm 41 with which a sleeve 43 is coaxially associated so as to allow a slight rotation which is controlled by a pair of first springs 42a, 42b; said sleeve has a fork 44 between whose prongs a support 46 for an electric power and/or data transmission connector is associated along an axis which is approximately parallel to the axis of the arm 41 and so as to allow oscillation on the diametrical plane of said arm and on the central plane with respect to the fork 44. Advantageously, the support 46 has a frustum-shaped tip which is shaped complementarily to the cavity 40 and from which a seat 47 for said connectors protrudes axially.

A third spring 48, arranged between the lateral surface of the support 46 and the adjacent sleeve 43, allows to control the oscillation of said support. The frame 3 of the device 1 has, at the second open end 49 which lies opposite the first closed end 33, a guiding assembly 50 for the autonomous underwater vehicle 2; said guiding assembly is constituted by a plurality of individual laminas 51 which are arranged side by side and so as to give the guiding assembly 50 a preferably frustum-like shape whose transverse cross-section is similar to that of the vehicle and whose apex is directed toward the first closed end 33.

The guiding assembly 50 therefore has an end which lies outside the frame and which, in plan view, is substantially petal-shaped and such as to facilitate the conveyance of the vehicle into the frame. Suitable devices 52 for transmitting/receiving signals which can be received and transmitted by other devices which are present inside the vehicle 2 are of course provided on the frame.

The device further comprises means suitable to lock the opening of said second half-frames 20a and 20b with respect to the first end 33 and to the second end 49; said means are constituted by suitable actuators 53 which are actuated by appropriately provided circuits and are adapted to force the interaction of a stem 54 which is connected to a body 55 which is respectively rigidly coupled to said second half-frames 20a and 20b, with said first and second ends 33 and 49, with which a preferably sleeve-shaped locator 56 is rigidly coupled. It has thus been observed that the invention has achieved the intended aim and objects, a device having been provided which allows to provide docking for moving autonomous underwater vehicles rapidly and safety as regards the integrity of the vehicle by way of the closable cage-like configuration of the frame and of the means for its centering and alignment.

The device further allows to temporarily stably couple the vehicle, thus allowing to rapidly and easily perform data acquisition or transmission and to transfer the energy required to restore the charge of the batteries contained therein. Finally, the particular configuration of the docking device allows to also use it for autonomous underwater vehicles having mutually different dimensions without particular adjustments or structural modifications.

The invention is of course susceptible of numerous modifications and variations, all of which are within the scope of the same inventive concept. The materials that constitute the individual components of the device may of course also be the most pertinent according to specific requirements.

The disclosures in Italian Patent Application No. TV99A000060, from which this application claims priority, are incorporated herein by reference.

Claims

1. A docking device for self-propelled autonomous underwater vehicles, characterized in that it is constituted by a closable cage-like frame which has means for acquiring data and transmitting energy from and to said vehicles and means for centering, alignment and temporary locking of said self-propelled vehicles.

2. The device according to claim 1, characterized in that it is constituted by a closable cage-like frame, provided with adapted perimetric guides for adapted first and second cables stretched between a submerged counterweight and a trestle which is rigidly coupled to the deck of a vessel.

3. The device according to claims 1 and 2, characterized in that it is associated with a first cable which is connected, at the other end, at a suitable articulation which is anchored to a base which can be arranged on the seabed.

4. The device according to claims 1 and 3, characterized in that said base is constituted by a body which is substantially shaped like a parallelepiped and has, at a transverse side, at least one protrusion which is inclined so as to form an acute angle with said transverse side, taking a clockwise rotation as positive, said shape of said protrusion allowing, during the lowering of said base onto the seabed, the automatic tipping of said base once it has reached the bottom.

5. The device according to claim 1, characterized in that said frame has a closable cage-like configuration and is substantially constituted by a plurality of first upper half-frames, each of which has, in transverse cross- section, a substantially C-shaped configuration and is fixed.

6. The device according to claims 1 and 5, characterized in that two second substantially L-shaped half-frames are rotatably and freely associated with the tips of the first wings of each one of said first half- frames and have such dimensions as to form a cage-like structure once the free ends have been arranged mutually adjacent.

7. The device according to claims 1 and 6, characterized in that said second half-frames are moved by means of suitable actuators which are constituted by pistons whose body is rigidly coupled at a first plate which is rigidly coupled to the first wing of said first half-frame and whose stem is rigidly coupled at a second plate which is rigidly coupled to one of the wings of said second half-frames.

8. The device according to one or more of the preceding claims, characterized in that said first and second half-frames have means for the centering and alignment of said autonomous underwater vehicle, said means being constituted by a plurality of contact pads which comprise cylindrical bodies which are rigidly coupled, at one end, to adapted third brackets which are rigidly coupled to one of said first or second half-frames and with which heads are telescopically associated, said heads being able to slide in contrast with appropriately provided flexible elements.

9. The device according to claims 1 and 8, characterized in that said contact pads are arranged in a radial configuration so that their heads lie, in the condition in which said frame is closed, at a curve which corresponds to the external contour of said autonomous underwater vehicle.

10. The device according to claims 1 and 9, characterized in that said heads have a seat for a ball, said heads being allowed to move between two conditions of maximum and minimum protrusion from said head with respect to said cylindrical body by way of the presence of at least one flexible element, such as a cylindrical helical compression spring.

11. The device according to one or more of the preceding claims, characterized in that means for the temporary locking of said vehicle are associated with said frame and are constituted by a plurality of bags which can be inflated with water which is preferably taken from the outside environment by means of pumps.

12. The device according to claims 1 and 11, characterized in that it comprises a first bag and a second bag which are arranged adjacent to the inner part of said frame arranged above the dorsal region of said autonomous underwater vehicle, and a third bag which is arranged at a first closed end of said frame, the nose of said autonomous underwater vehicle interacting with said third bag.

13. The device according to claims 1 and 12, characterized in that said third bag cooperates, in its actuation, with additional means for the alignment and locking of said autonomous underwater vehicle, said means being constituted by two wings which have a substantially triangular plan shape and are rotatably associated, at mutually parallel and adjacent ends, with a pair of bases which are rigidly coupled to said frame in a region located above the autonomous underwater vehicle, particularly in a region located above a dorsal fin thereof.

14. The device according to claims 1 and 13, characterized in that said wings are arranged, at rest, so as to have mutually opposite vertices, said wings being able to rotate in a single direction so as to allow the complete passage of said fin during the insertion of said vehicle in said frame and the locking of said fin once an opposite movement is applied to said vehicle, flexible means interacting with said wings in order to reposition them so that their vertices are mutually opposite.

15. The device according to claims 1 and 14, characterized in that the arrangement of said bases and the shape of said third bag are such that the movement of said fin beyond said wings corresponds to the resting of said prow of said vehicle at said third bag which, due to the inertia of the vehicle, is compressed, expelling the water pumped into it earlier, and is then filled with water again, expanding it, in order to push said vehicle backward.

16. The device according to one or more of the preceding claims, characterized in that it comprises an additional device on said frame which is meant to recharge the batteries of said vehicle and to download or upload data from or to said vehicle, at an adapted cavity formed therein, said additional device being constituted by an arm with which a sleeve is coaxially associated so that it can perform a slight rotation which is controlled by two first springs, said sleeve being provided with a fork between whose prongs a support for an electric power and/or data transmission connector is associated on an axis which is approximately parallel to the axis of said arm and so as to allow oscillation on the diametrical plane of said arm and on a central plane with respect to said fork.

17. The device according to claims 1 and 16, characterized in that said support has a frustum-shaped tip which is shaped complementarily to said cavity and from which a seat for said connectors protrudes axially, a third spring arranged between the lateral surface of said support and said adjacent sleeve allowing to control the oscillation of said support.

18. The device according to one or more of the preceding claims, characterized in that said frame has, at its second open end, which lies opposite said first closed end, a guiding assembly for said autonomous underwater vehicle, said guiding assembly being constituted by a plurality of individual laminas which are arranged mutually side by side and so as to give said guiding assembly a frustum-shaped configuration whose apex is directed toward said third bag.

19. The device according to one or more of the preceding claims, characterized in that it comprises means which are adapted to lock the opening of said second half-frames with respect to said first and second ends, said means being constituted by suitable actuators, actuated by appropriately provided circuits, which are adapted to force the interaction of a stem, which is connected to a body which is rigidly coupled respectively to said second half-frames, with said first and second ends and with which a preferably sleeve-shaped locator is rigidly coupled.