GB2343416A

GB2343416A - Autonomous underwater vehicles

Info

Publication number: GB2343416A
Application number: GB9903689A
Authority: GB
Inventors: Robert Weatherburn; John Henry Foxwell; Duncan James Edward Mcgowan
Original assignee: SEA PROBE Ltd
Current assignee: SEA PROBE Ltd
Priority date: 1998-11-06
Filing date: 1999-02-18
Publication date: 2000-05-10
Anticipated expiration: 2019-02-18
Also published as: GB2343416B; GB9903689D0; GB9824263D0

Abstract

An autonomous underwater vehicle 1 comprises a housing which is formed from at least two telescopable members 2A, 2B, and control means operative to control the telescoping of the members 2A, 2B such that the overall length of the vehicle 1 can be varied. The vehicle further comprises distribution means which is operative to distribute the weight of at least some of the payload 12, 16, 17 of the vehicle 1. Tanks 10,11,12 can be filled or emptied of water by means of a pump 13 to adjust the buoyancy and tilt of the vehicle. An electric motor 19 powered by battery units 16,17 drives a propeller 5.Manoeuvrability of the vehicle is via foils 20.

Description

AUTONOMOUS UNDERWATER VEHICLES The present invention relates to improvements in Autonomous Underwater Vehicles (AUVs), and more particularly, but not limited to, AUVs suitable for deployment in the sea from aircraft.

AUVs deployed from aircraft are known to take measurements in the sea such as depth, salinity, temperature, and pollution. They often include a hollow body with a propulsion mechanism, battery and a sensor/s to take the measurements. The AUVs are dropped into the sea from an aircraft laying platform which is generally only capable of launching AUVs of about 1 metre in length. In the water, AUVs are preferably required to have neutral buoyancy so that energy from the battery is not used to keep the AUV buoyant by forward movement at the required depth such as just under the surface. As a result, a relatively high proportion of the AUV volume needs to be used as a buoyancy tank/s. As the size of such AUVs is limited by the aircraft laying platform, and the AUV needs a relatively large buoyancy tank/s, there is a limit to the AUV weight. This has an adverse effect on the battery size and hence useful endurance life of AUVs, and a limitation on its capabilities in general.

The invention seeks to provide an AUV to solve this problem.

According to the invention an autonomous underwater vehicle comprises a housing which is formed from at least two telescopable members and control means, the control means being operative to control the telescoping of the members such that the overall length of the vehicle can be varied.

By'telescopable'we do not necessarily mean that one member may be accommodated entirely within the other member.

The control means may comprise a locking means adapted to retain the telescopable members in a relatively contracted condition, and activator means arranged when activated to release the locking means, thereby to permit relative movement apart of the telescopable members from said relatively contracted position.

Preferably the at least two telescopable members are of tubular construction.

Most preferably the at least two telescopable members are of cylindrical shape.

Preferably the vehicle comprises distribution means which is operative to distribute the weight of at least some of the payload of the submarine vehicle.

Preferably the payload is divided at least in part into a plurality of units which are adapted to be capable of substantially translational movement with respect to the vehicle.

Preferably the distribution means comprises at least one conveyor assembly.

Preferably the distribution means is operative to control the relative positions of the units one to another.

Preferably the AUV has a parachute.

The actuator means is preferably then arranged to be operated by opening of a parachute.

Preferably the AUV has a propulsion means.

Preferably the AUV has a battery.

Preferably the AUV has one or more sensors.

Preferably the AUV has one or more foils to adjust the angle of attack in the water, to stabilise the vehicle, and/or to provide a means for turning.

Preferably the AUV has at least one buoyancy tank.

Preferably means are provided to fill and empty the or each buoyancy tank with water to adjust the buoyancy thereof.

In one embodiment means are provided to distribute the contents of the AUV when it expands into said second position.

In one embodiment the housing is formed from two telescopable members with a seal therebetween.

An AUV in accordance with the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 shows a schematic diagram of the AUV before deployment in a first contracted position, and Figure 2 shows a schematic diagram of the AUV in use in a second expanded position.

Referring to Figure 1 there is shown an AUV 1 having a vehicle housing formed from two generally cylindrical telescopable members 2A, 2B.

Member 2A is the front of the AUV and generally rounded at one end into a hydrodynamic shape, and member 2B forms the rear. Member 2B has a removable cap 3 which houses a parachute 4. Removal of the cap 3 exposes a propulsion means in the form of a propeller 5 between the cap 3 and a conical end wall 6. The open end of member 2A includes a circumferential flange 7 extending radially inward, and the open end of member 2B includes a circumferential flange 8 extending radially outward. An annular seal, such as an O-ring 9, is provided adjacent flange 8.

Inside the housing is a front buoyancy tank 10, a rear buoyancy tank 11 and a main central buoyancy tank 12. Tanks 10,11,12 can be filled or emptied of water by means of a pump 13 to adjust the buoyancy and tilt of the AUV 1. Pump 13 may be connected through a conduit 14 to an external aperture 15 in member 2B. A power source is provided in the form of two battery units 16,17 along with one or more sensors 18 (including associated circuits). An electric motor 19 drives the propeller 5. The AUV has one or more foils 20 (eg four equally-spaced radially around the AUV) on the outside of inner wall 6 to adjust the angle of attack to allow manoeuvrability in vertical and horizontal planes, to stabilise the vehicle, and/or to turn the vehicle, in the water.

An activator means to allow the members to move from a first contracted position to a second expanded position is provided by a catch 21.

Catch 21 may be operated when parachute opens allowing the two members 2A, 2B to telescope or expand apart until flanges 7 and 8 engage around seal 9 as shown in Figure 2 (a lock, not shown, may be provided to secure the two members in the expanded position). As shown in Figure 2, when members 2A, 2B telescope apart, a conveyer or other transport device (not shown) distributes the weight of payload by spacing the batteries, buoyancy chambers and sensor/s.

In use, the AUV is ejected from an aircraft and the parachute opens to reduce its velocity. As the parachute opens, so catch 21 is operated, and the front member 2A telescopes away from the rear member 2B under the influence of gravity. When the AUV hits the water, the end cap is released whereby the parachute is jettisoned. The payload is distributed and the buoyancy tanks filled until the AUV has neutral buoyancy in the water. The AUV can then be driven horizontally and/or vertically by the motor and adjustment of the buoyancy tanks.

Because the AUV expands in volume, a greater payload weight can be inserted inside the housing whilst maintaining neutral buoyancy. In its contracted form it can meet the maximum length requirement of the aircraft laying platform, eg approximately 1 metre. Its effective density can thus be changed from say around 2 in a contracted form to around 1.02 in an expanded form.

The AUV may also be a buoy, in which case it may not be necessary for it have a propulsion means or the need to move horizontally or vertically in the sea.

The AUV may also be fitted with a different number of buoyancy tanks.

The method by which the telescopic members of the housing are expanded may be different to that described. For example this could be achieved by mechanical drive means such as worm screw driving the members apart or by hydraulic or pneumatic rams. Alternatively this may be done by release of a gas to increase pressure in the housing forcing the members apart.

Also the telescopic members need not expand whilst in flight with the parachute open. For example the AUV could land in the water with a temporary buoyancy aid which is jettisoned after the members have expanded.

The method to hold the two sections in the expanded position may be, but is not limited to, a mechanical lock, a strut, adhesive, or case deformation.

The AUV of the invention may be designed to launch from laying platforms other than those in aircraft, eg from a ship or other marine vessel.

The AUV housing may be formed of any suitable material such as plastics or metal.

Instead of an O-ring seal, other types of seals may be used in conjunction with or alternatively to an O-ring, such as a rubber gaiter and/or a glued and sealed joint.

Further modifications will be apparent to those skilled in the art without departing from the scope of the present invention.

Claims

CLAIMS 1. An autonomous underwater vehicle comprising a housing which is formed from at least two telescopable members and control means, the control means being operative to control the telescoping of the members such that the overall length of the vehicle can be varied.
2. A vehicle as claimed in claim 1 in which the control means comprises a locking means adapted to retain the telescopable members in a relatively contracted condition, and activator means arranged when activated to release the locking means, thereby to permit relative movement apart of the telescopable members from said relatively contracted position.
3. A vehicle as claimed in claim 1 or claim 2 in which the at least two telescopable members are of tubular construction.
4, A vehicle as claimed in claim 3 in which the at least two telescopable members are of cylindrical shape.
5. A vehicle as claimed in any one of the preceding claims in which the submarine vehicle comprises distribution means which is operative to distribute the weight of at least some of the payload of the vehicle.
6. A vehicle as claimed in claim 5 in which the payload is divided at least in part into a plurality of units which are adapted to be capable of substantially translational movement with respect to the vehicle.
7. A vehicle as claimed in claim 6 in which the distribution means comprises at least one conveyor assembly.
8. A vehicle as claimed in claim 6 in which the distribution means is operative to control the relative positions of the units one to another.
9. A vehicle as claimed in any of the preceding claims in which the vehicle has a parachute.
10. A vehicle as claimed in claim 9 as appended to claim 2 in which the activator means is arranged to be operated by opening of the parachute.
11. A vehicle as claimed in any of the preceding claims comprising a propulsion means.
12. An autonomous underwater vehicle substantially as described with reference to the accompanying drawings.

12. A vehicle as claimed in claim 11 comprising one or more foils to adjust the angle of attack in the water, to stabilise the vehicle, and/or to provide a means for turning.

13. A vehicle as claimed in any of the preceding claims comprising at least one buoyancy tank, and means are provided to fill and empty the or each buoyancy tank with water to adjust the buoyancy thereof.

14. An autonomous underwater vehicle substantially as described with reference to the accompanying drawings.

1. An autonomous underwater vehicle for deployment in the sea from aircraft by means of a parachute carried by the vehicle, and comprising a housing which is formed from at least two telescopable members and control means operative on opening of the parachute to control the telescoping of the members such that the overall length of the vehicle is then increased.

2. A vehicle as claimed in claim 1 in which the control means comprises a locking means adapted to retain the telescopable members in a relatively contracted condition, and activator means arranged when activated to release the locking means, thereby to permit relative movement apart of the telescopable members from said relatively contracted position.

3. A vehicle as claimed in claim 1 or claim 2 in which the at least two telescopable members are of tubular construction.

4, A vehicle as claimed in claim 3 in which the at least two telescopable members are of cylindrical shape.

5. A vehicle as claimed in any one of the preceding claims, comprising distribution means which is operative to distribute the weight of at least some of the payload of the vehicle.

6. A vehicle as claimed in claim 5 in which the payload is divided at least in part into a plurality of units which are adapted to be capable of substantially translational movement with respect to the vehicle.

7. A vehicle as claimed in claim 6 in which the distribution means v comprises at least one conveyor assembly.

8. A vehicle as claimed in claim 6 in which the distribution means is operative to control the relative positions of the units one to another.

9. A vehicle as claimed in any of the preceding claims comprising a propulsion means.

10. A vehicle as claimed in any one of claims 1 to 9, comprising one or more foils to adjust the angle of attack in the water, to stabilise the vehicle, and/or to provide a means for turning.

11. A vehicle as claimed in any of the preceding claims comprising at least one buoyancy tank, and means are provided to fill and empty the or each buoyancy tank with water to adjust the buoyancy thereof.