CROSS-REFERENCE TO RELATED APPLICATIONS

This Patent Appl ication claims priority from Italian Patent Application No . 102022000011063 filed on May 26 , 2022 , the entire disclosure of which is incorporated herein by reference .

TECHNICAL FIELD

The present invention relates to a coupling device for connecting an unmanned underwater vehicle to a floating vehicle in a body of water and to a navigation assembly comprising said coupling device .

BACKGROUND

The use of Autonomous Unmanned Vehicles (AUV) on a worksite for carrying out underwater operations , such as for example operations for inspecting underwater hydrocarbon production plants or the surveillance of underwater structures , is currently well known .

Generally, said AUVs are surface assisted by a floating support vehicle , which is configured to launch, control and haul the AUV on board .

As they are not connected to external power supply sources , these AUVs have limited range in terms of service time , space that can be covered with a single recharge and force that can be exerted .

Such range limits , for example , do not allow the known AUVs to navigate from one underwater worksite to another i f the distance between said worksites is greater than the maximum distance that can be travelled by the AUV with a single recharge .

Therefore , in order to trans fer the AUVs from one underwater worksite to another, it is necessary to haul the AUV on board the floating support vehicle , transport the AUV on board the floating support vehicle and re-launch the AUV at the subsequent underwater worksite .

Furthermore , when the AUV needs to be recharged due to depleted energy reserves , the AUV to be recharged is typically hauled on board the floating support vehicle or, alternatively, is stowed in an underwater docking station connected to the floating support vehicle via an umbilical .

However, docking the AUV to the underwater docking station is challenging due to unpredictable shi fts of the AUV relative to the underwater docking station due to turbulence in the body of water . As a result , said docking is typically performed while the floating support vehicle is substantially stationary on the body of water .

Moreover, the launch and recovery of the AUV and/or the underwater docking station require a large amount of time and can only be carried out under favourable weather and environmental conditions .

In particular, in order to launch and recover the AUV and/or the underwater docking station, the floating vehicle must be equipped with a launch and recovery system . Said launch and recovery systems are typically bulky, require long time and high cost for instal lation/de-installation on board the floating vehicle and take up a large amount of space on the floating vehicle , which must be speci fically designed according to the use of said launch and recovery system .

SUMMARY One obj ect of the present invention is to provide a coupling device for connecting an unmanned underwater vehicle to a floating vehicle in a body of water, which is capable of obviating the drawbacks of the prior art .

In particular, the obj ect of the present invention is to allow the transport , recharging and data exchange of the unmanned underwater vehicle in a simple and risk- free manner, while keeping the unmanned underwater vehicle in the body of water .

In accordance with the present invention, there is provided a coupling device for connecting an unmanned underwater vehicle to a floating vehicle in a body of water, the coupling device being connectable to the floating vehicle by means of a cable so as to be towed in a forward direction by the floating vehicle and comprising : a connecting device configured to be connected mechanically and/or electrically and/or for data exchange to the unmanned underwater vehicle in the body of water ; and

- a hydrodynamic resistance structure configured to cause on the coupling device a counter force opposing the forward motion of the coupling device in the body of water .

The present invention enables the unmanned underwater vehicle to be connected to the floating vehicle to allow the recharging of the unmanned underwater vehicle and its transport from one worksite to another without the need to haul the unmanned underwater vehicle on board the floating vehicle . In other words , the unmanned underwater vehicle can be kept in the body of water while transporting and/or recharging the unmanned underwater vehicle .

In this way, it is not necessary for the floating vehicle to be equipped with a bulky launch and recovery system to launch and recover the unmanned underwater vehicle and, as a result , the floating vehicle may be smaller or allocate the spaces used for the launch and recovery system to other purposes . Since the launch and recovery system is not required, the unmanned underwater vehicle can be transported and/or recharged in a short time and even under adverse weather and environmental conditions .

In addition, as the coupling device can be connected to the floating vehicle via a cable , it is possible to lower the coupling device deep into the body of water . In this way, the unmanned underwater vehicle can be kept at the underwater worksite during recharging, without the need for the unmanned underwater vehicle to rise up close to the surface of the body of water .

In particular, the hydrodynamic resistance structure is configured to cause a hydrodynamic friction and/or an increase in the added mass of the coupling device when the coupling device moves forward in the body of water .

Due to the hydrodynamic resistance structure , when the unmanned underwater vehicle comes into contact with the coupling device , it is possible to counter the forward motion of the coupling device due to the thrust of the unmanned underwater vehicle . In addition, the hydrodynamic resistance structure gives stability to the coupling device when the coupling device i s towed by the floating vehicle in the body of water . In this way, the connection between the unmanned underwater vehicle and the coupling device can be made in a simple and quick way even when the floating vehicle is navigating on the body of water .

Within the scope of the present invention, the term "added mass" refers to the additional amount of inertia of a body moving in a fluid due to the displacement of a given volume of water .

In particular, the connecting device comprises at least one mechanical connector configured to releasably engage the unmanned underwater vehicle to the coupling device .

In this way, the unmanned underwater vehicle can be kept integrally connected to the coupling device while the unmanned underwater vehicle is being trans ferred from one worksite to another . Furthermore , the mechanical connector allows the unmanned underwater vehicle to be selectively coupled to/uncoupled from the coupling device .

In particular, the connecting device comprises an inductive connector configured to connect electrically and/or for data exchange the unmanned underwater vehicle to the coupling device .

In this way, when the unmanned underwater vehicle is connected to the inductive connector, it is possible to recharge the unmanned underwater vehicle with electrical energy and at the same time communicate via cable with the unmanned underwater vehicle .

In particular, the coupling device compri ses a locali zation assembly, which is configured to enable optical and/or acoustic and/or magnetic locali zation of the coupling device by the unmanned underwater vehicle and preferably comprises at least one optical identi fication element and/or an acoustic transmitter and/or a magnetic sensor .

Thanks to the acoustic transmitter, the unmanned underwater vehicle can locate the coupling device from long distances , in particular from approximately 2000 metres to approximately 5 metres away, and thanks to the optical identi fication element , the unmanned underwater vehicle can accurately locate the position of the connecting device from short distances , in particular from less than 5 metres away .

In accordance with one embodiment , the hydrodynamic resistance structure comprises an annular wall arranged around the connecting device to provide hydrodynamic friction when the coupling device moves forward in the body of water .

The hydrodynamic friction causes hydrodynamic resistance to the forward motion in the body of water, making the coupling device stable during said forward motion .

In this way, hydrodynamic resistance can be provided against the forward motion of the coupling device when, during docking, the unmanned underwater vehicle pushes on the coupling device, while keeping the si ze and mas s of the coupling device small .

In particular, the annular wall is parachute-shaped, so as to increase the hydrodynamic friction of the hydrodynamic resistance structure in the body of water .

In particular, the annular wall extends transversely with respect to the forward direction and comprises an outer circumferential edge , which is folded in the forward direction .

In this way, during the forward motion of the coupling device in the body of water, a body of water can be directed against the annular wall , further increas ing the hydrodynamic resistance of the hydrodynamic resistance structure against the forward motion in the body of water .

In particular, the annular wall is provided with a plurality of through openings .

In this way, the hydrodynamic resistance of the hydrodynamic resi stance structure against the forward motion in the body of water can be modulated by adequately si zing the through openings .

In accordance with a further embodiment , the hydrodynamic resistance structure comprises an enclosure , which bounds an inner cavity for containing water of adj ustable si ze .

When the inner cavity contains water, an added mass is generated for the coupling device and, as a result , the inertia of the coupling device is increased so as to increase the counter force when connecting the coupling device to the unmanned underwater vehicle .

In particular, the enclosure comprises a first portion; a second portion rotatably coupled to the first portion about a rotation axis transverse with respect to the forward direction; and a flexible membrane , which is coupled to the first and the second portion and bounds the inner cavity together with the first and the second portion .

As the coupling device moves forward through the body of water, the water pressure in the inner cavity causes a relative rotation between the first and the second portion and the expansion of the flexible membrane . In this way, the volume of the inner cavity is increased and, as a result , the added mass of the coupling device is increased by the water contained therein .

In particular, the enclosure is provided with at least one connection opening configured to fluidically connect the inner cavity to the body of water to allow filling and emptying of the inner cavity .

In particular, the hydrodynamic resistance structure comprises at least one fin movable between an open position and a closed position; the at least one movable fin being configured to arrange itsel f in the open position when the coupling device moves forward in the body of water so as to increase the hydrodynamic friction of the coupling device in the body of water .

A further obj ect of the present invention is to provide a navigation assembly which is free from the drawbacks of the prior art .

In accordance with the present invention, there is provided a navigation assembly comprising :

- a floating vehicle configured to navigate on a body of water ; a coupling device as claimed in any one of the foregoing Claims ; and

- a connecting cable , which connects electrically, for data exchange and for towing purposes , the floating vehicle to the coupling device .

The navigation as sembly allows the unmanned underwater vehicle to be recharged and trans ferred from one worksite to another while keeping the unmanned underwater vehicle in the body of water during transport and/or recharging of the unmanned underwater vehicle .

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the present invention will be apparent from the following description of non-limiting embodiments thereof , with reference to the accompanying drawings , wherein :

- Figure 1 is a side elevation view, with parts removed for clarity, of a navigation assembly made in accordance with a first embodiment of the present invention;

- Figures 2 and 3 are perspective views , with parts removed for clarity, of a coupling device of the navigation assembly in Figure 1 ;

- Figure 4 is a side elevation view, with parts removed for clarity, of a navigation assembly made in accordance with a second embodiment of the present invention;

- Figures 5 and 6 are perspective views , with parts removed for clarity, of a coupling device of the navigation assembly in Figure 4 in respective operating configurations ;

- Figure 7 is a sectional view, with parts removed for clarity, of the coupling device in Figure 6 ; and

- Figure 8 is a side elevation view, with parts removed for clarity, of the navigation assembly in Figure 1 in a further operating configuration .

DESCRIPTION OF EMBODIMENTS

With reference to Figure 1 , number 1 indicates , as a whole , a navigation assembly, which is used in a body of water 2 and made in accordance with a first embodiment of the present invention .

The navigation assembly 1 comprises a floating vehicle 3 configured to navigate on the body of water 2 ; an unmanned underwater vehicle 4 configured to navigate in the body of water 2 ; a coupling device 5 to connect the underwater vehicle 4 to the floating vehicle 3 in the body of water 2 ; and a connecting cable 6 , which connects electrically, for data exchange and for towing purposes , the floating vehicle 3 to the coupling device 5 .

The floating vehicle 3 may be any type of manned or unmanned vessel configured to navigate on a body of water . In the example described and illustrated herein, which does not limit the present invention, the floating vehicle 3 is an autonomous unmanned vehicle .

Moreover, in the example described and illustrated herein, the underwater vehicle 4 is of the AUV (Autonomous Unmanned Vehicle ) type .

In accordance with a further embodiment , not shown in the accompanying drawings , the underwater vehicle 4 is of the ROV (Remoted Operated Vehicle ) type .

In accordance with a variant of the present invention, not shown in the accompanying drawings , the navigation assembly 1 compri ses a plurality o f connecting cables 6 . In particular, the navigation assembly 1 comprises a first connecting cable to electrically connect the floating vehicle 3 to the coupling device 5 , a second connecting cable to connect the floating vehicle 3 to the coupling device 5 for data exchange , and a third connecting cable to mechanically connect the coupling device 5 to the floating vehicle 3 for towing purposes .

In addition, the navigation assembly 1 comprises a cable management system 7 , which is arranged on board the floating vehicle 3 and is configured to selectively wind/unwind the connecting cable 6 . In this way, it is possible to control the length of the connecting cable 6 and to adj ust the depth of the coupling device 5 in the body of water 2 . In particular, the cable management system 7 comprises a winch 8 .

With reference to Figure 2 , the coupling device 5 can be connected to the floating vehicle 3 via the connecting cable 6 so as to be towed in a forward direction D by the floating vehicle 3 ( Figure 1 ) and comprises a connecting device 9 configured to be connected mechanically and/or electrically and/or for data exchange to the underwater vehicle 4 in the body of water 2 ; and a hydrodynamic resistance structure 10 configured to cause on the coupling device 5 a counter force F opposing the forward motion of the coupling device 5 in the body of water 2 .

In greater detail , the hydrodynamic resistance structure 10 is configured to cause a hydrodynamic friction when the coupling device 5 moves forward through the body of water 2 .

The coupling device 5 extends around an axis Al , which is substantially parallel to the forward direction D when the coupling device 5 moves forward through the body of water 2 ( Figure 1 ) . In particular, the hydrodynamic resistance structure 10 extends around the connecting device 9 .

In accordance with the present invention, the connecting device 9 comprises two mechanical connectors 11 configured to releasably couple the underwater vehicle 4 to the coupling device 5 . In particular, each mechanical connector 11 comprises a quick coupling and release mechanism, not shown in the accompanying drawings .

It is understood that the number and layout of the mechanical connectors 11 is purely exemplary and should not be construed as limiting the present invention .

Furthermore , the connecting device 9 comprises an inductive connector 12 , which is configured to connect electrically and/or for data exchange the underwater vehicle

4 to the coupling device 5 .

In accordance with variants of the present invention, not shown in the accompanying drawings , the connecting device 9 comprises a plurality of inductive connectors 12 .

In accordance with one embodiment , the coupling device

5 comprises a locali zation assembly 13 configured to enable optical and/or acoustic and/or magnetic locali zation of the coupling device 5 by the underwater vehicle 4 . In particular, the locali zation assembly 13 comprises two optical identi fication elements 14 , one acoustic transmitter 15 , such as for example a sonar or beacon, and one magnetic sensor, not shown in the accompanying drawings . In greater detail , each optical identi fication element 14 is arranged on the hydrodynamic resistance structure 10 and comprises an identi fication code , such as for example a QR code or a bar code , and/or a light element , such as for example an LED .

In addition, the inductive connector 12 is configured to generate a magnetic field to guide the underwater vehicle 4 towards the inductive connector 12 when the underwater vehicle is within approximately 50 centimetres of the connecting device 9 .

In the example described and illustrated herein, the hydrodynamic resistance structure 10 comprises an annular wall 16 arranged around the connecting device 9 to provide hydrodynamic friction when the coupling device 5 moves forward in the body of water 2 . In particular, the annular wall 16 extends circumferentially around the axis Al and is arranged transversely to the axis Al .

With reference to Figure 3 , the annular wall 16 is parachute-shaped . In particular, the annular wall 16 comprises an outer circumferential edge 17 , which is folded in the forward direction D .

Moreover, the annular wall 16 is provided with a plurality of through openings 18 arranged around the axis Al .

Figure 4 shows the navigation assembly 1 made in accordance with a second embodiment of the present invention .

The navigation assembly 1 comprises a floating vehicle 19 configured to navigate on the body of water 2 ; the unmanned underwater vehicle 4 conf igured to navigate in the body of water 2 ; a coupling device 20 to connect the underwater vehicle 4 to the floating vehicle 19 in the body of water 2 ; and a connecting cable 6 , which connects electrically, for data exchange and for towing purposes , the floating vehicle 19 to the coupling device 20 .

In the example described and illustrated herein, which does not limit the present invention, the floating vehicle 19 is an autonomous unmanned sailing vehicle . In particular, the floating vehicle 19 comprises a sail 21 , a solar energy storage device 22 , and a hollow keel 23 configured to house the coupling device 20 .

In accordance with variants of the present invention, not shown in the accompanying drawings , the floating vehicle 19 may comprise additional renewable energy conversion devices , such as for example wind energy conversion systems or wave energy conversion systems .

Figures 5 and 6 show the coupling device 20 in a closed configuration and an open configuration, respectively . The coupling device 20 comprises a hydrodynamic resistance structure 24 configured to cause a hydrodynamic friction and an increase in the added mass of the coupling device 20 when the coupling device 20 moves forward in the body of water 2 .

In particular, the coupling device 20 extends along an axis A2 substantially parallel to the forward direction D when the coupling device 20 moves forward through the body of water 2 ( Figure 4 ) .

The hydrodynamic resistance structure 24 comprises an enclosure 25 stretched along the axis A2 and two stabil i zing fins 26 ( only one of which is vi sible in Figures 5 and 6 ) , each of which is arranged on the enclosure 25 and has a hydrodynamic profile designed to stabili ze the traj ectory of the coupling device 20 when the coupling device 20 moves forward through the body of water 2 .

With reference to Figure 7 , the enclosure 25 bounds an inner cavity 27 for containing water of adj ustable si ze .

In particular, the enclosure 25 comprises a portion 28 ; a portion 29 rotatably coupled to the portion 28 about a rotation axis A3 transverse to the axis A2 ; and a flexible membrane 30 , which is coupled to the portions 28 and 29 and bounds the inner cavity 27 together with the portions 28 and 29 .

In greater detai l , the portion 28 comprises a rounded tip end 31 , to which the portion 29 is rotatably coupled . The coupling device 20 comprises one end 32 , which is opposite to the end 31 along the axis A2 and has an opening 33 .

The portion 28 comprises a transverse inner wall 34 on which the connecting device 9 is arranged . In particular, the inner wall 34 extends into the opening 33 between the portions 28 and 29 in a direction substantially perpendicular to the axis A2 .

The flexible membrane 30 is attached to the portion 29 and the inner wal l 34 . In particular, the flexible membrane 30 is configured to extend so as to increase the si ze of the inner cavity 27 when the coupling device 20 moves forward in the body of water 2 .

In the closed configuration ( Figure 5 ) , the flexible membrane 30 is fully retracted and the si ze of the inner cavity 27 is the smallest .

In the open configuration ( Figure 6 ) , the flexible membrane 30 is fully extended and the si ze of the inner cavity 27 is the largest .

In addition, the enclosure 25 is provided with connection openings 35 configured to fluidically connect the inner cavity 27 to the body of water 2 .

In the non-limiting example of the present invention described and illustrated herein, each portion 28 , 29 comprises respective connection openings 35 .

It is understood that the number and layout of the connection openings 35 may vary without however departing from the scope of the present invention . By way of example , in accordance with a variant of the present invention, the connection openings 35 are only obtained in the portion 28 .

Furthermore , the hydrodynamic resistance structure 24 comprises two movable fins 36 and 37 between a closed position ( Figure 5 ) and an open position ( Figures 6 and 7 ) . Each movable fin 36 , 37 is configured to arrange itsel f in the open position ( Figures 6 and 7 ) when the coupling device 20 moves forward through the body of water 2 so as to increase the hydrodynamic resistance of the coupling device 20 in the body of water 2 .

In particular, the movable fin 36 is rotatably coupled to the portion 28 about a rotation axis transverse to the axis A2 , and the movable fin 37 is rotatably coupled to the portion 29 about a further rotation axis transverse to the axis A2 .

In addition, the coupling device 20 comprises an actuation system, not shown in the accompanying drawings , which is configured to actuate the rotation of the portion 28 relative to the portion 29 about the rotation axis A3 so as to change the configuration of the coupling device 20 from the closed configuration ( Figure 5 ) to the open configuration ( Figure 6 ) , and vice versa .

In accordance with one embodiment , the actuation system is configured to actuate the rotation of each movable fin 36 , 37 between the closed position ( Figure 5 ) and the open position ( Figures 6 and 7 ) .

In use and with reference to Figure 8 , when the underwater vehicle 4 comes into contact with the connecting device 9 of the coupling device 5 , the underwater vehicle 4 causes the coupling device 5 to accelerate in the forward direction D . Thanks to the shape of the annular wall 16 , the hydrodynamic resistance structure 10 , reacting to this acceleration, supplies a counter force F opposing the forward motion of the coupling device 5 in the body of water 2 so as to allow the connection of the underwater vehicle 4 to the connecting device 9 .

In other words , this acceleration results in an increase in the speed of the coupling device 5 and, due to this increase in speed, the annular wall 16 of the hydrodynamic resistance structure 10 increases the hydrodynamic friction of the coupling device 5 in the body of water 2 .

In use and with reference to Figure 7 , when the coupling device 20 is towed in the forward direction D by the floating vehicle 19 , the actuation system rotates the portion 28 relative to the portion 29 about the rotation axis A3 so that the coupling device 20 switches from the closed configuration ( Figure 5 ) to the open configuration ( Figures 6 and 7 ) , thereby extending the flexible membrane 30 and increasing the si ze of the inner cavity 27 . In particular, as the coupling device 20 moves forward through the body of water 2 , water enters the inner cavity 27 through the connection openings 35 . The increase in si ze of the inner cavity 27 , which contains water, corresponds to an increase in the added mas s of the coupling device 20 in the body of water 2 .

Moreover, as the coupling device 20 moves forward through the body of water 2 , the actuation system rotates each movable fin 36, 37 about a rotation axis transverse to the axis A2 . In this way, each movable fin 36 , 37 switches from the closed position ( Figure 5 ) to the open position ( Figures 6 and 7 ) , thereby increasing the hydrodynamic friction of the coupling device 20 in the body of water 2 .

When the underwater vehicle 4 comes into contact with the connecting device 9 of the coupling device 20 , the hydrodynamic resi stance structure 24 causes a counter force F opposing the forward motion of the coupling device 20 in the body of water 2 so as to allow the connection of the underwater vehicle 4 to the connecting device 9.

The counter force F is partly caused by the inertia force due to the added mass of the coupling device 20 which opposes an acceleration of the coupling device 20 , and partly caused by the friction force due to the hydrodynamic friction of the movable fins 36 and 37 in the open position .

Lastly, it is clear that the present invention can be subj ect to variations with respect to the embodiments described with reference to the accompanying drawings without however departing from the scope of protection of the claims .