Highly Maneuverable Underwater Vehicle

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefore.

(1) Field of the Invention

The present invention relates to an underwater vehicle having a high degree of maneuverability, and deals more particularly with an underwater vehicle having hydraulically actuated, articulated joints to control the movement of the vehicle through the water.

(2) Description of the Prior Art

Conventional underwater vehicles, such as torpedoes, are designed in a straight and elongated fashion so that they will run true. These types of vehicles are typically required to run at high speed in a generally straight path toward a target. Evasive action by the target requires the vehicle to have a degree of maneuverability in order to successfully engage the target. Steering fins are provided, typically at the aft end of the vehicle, to control the direction of the vehicle. However, the effectiveness of the fins is reduced by the straight and elongated shape of the vehicle. Steering vanes may also be provided at the forward end of the vehicle for increased maneuverability. However, such vanes greatly increase the vehicle's drag. The increased drag would require the vehicle to have a larger propulsion unit or the vehicle would move more slowly through the water. A larger propulsion unit may result in increased size, cost and radiated noise, and a slower vehicle may be incapable of attaining the target.

Another method which can be used to maneuver a vehicle is to bend the vehicle in the desired direction of travel. As the vehicle travels through the water in a straight path, a slight bend of the forward end in one direction would result in increased pressure against the opposite side of the vehicle. For example, bending the forward end of the vehicle to the right of the initial path results in increased pressure against the left side of the vehicle. The increased pressure forces the vehicle to turn to the right. To allow bending of the vehicle, the vehicle may be articulated, i.e., provided with a number of flexible joints. Underwater vehicles with flexible joints are well known in the art. The submersible sea train of Combs, Pat. No. 3,478,711, has a number of submersible cargo vessels coupled together and designed to be towed through the water by a forward propulsion unit. Sensors within the towed vessels activate ballast pumps which maintain proper relative buoyancy and submergence of the vessels and maintain the towed vessels in line with the propulsion unit. The forward propulsion unit provides the directional control for the sea train and there is no mechanism within the units for providing right and left control of the units. The system is not adapted for underwater vehicles having an aft propulsion unit, such as modern torpedoes. Mosvold, Pat. No. 3,461,829, describes a system for connecting and steering a pushed vessel, such as a barge being pushed by a tugboat. The system consists of a universal coupling connecting the barge and tugboat as well as securing cables from the tugboat to the barge. The cables are payed in and out to provide steering of the barge. The system is adapted for surface vessels and provides directional control only in a horizontal plane.

There is a need to provide an improved method of maneuvering a high speed, aft driven, underwater vehicle which does not appreciably increase drag or require a larger propulsion unit for the vehicle. However, given the large inventory and investment in present torpedoes, the maneuvering method must be able to be retrofit within the general geometry of present torpedoes and must further be able to utilize existing torpedo components.

Accordingly, it is a general purpose and object of the present invention to provide a highly maneuverable underwater vehicle which maintains the present, long cylindrical shape of present torpedoes.

Another object is to provide a highly maneuverable underwater vehicle having a maneuvering system which can control movement of the torpedo in a combination of horizontal and vertical planes when the torpedo has an aft propulsion drive.

A still further object is to provide a maneuvering system which can be retrofit to existing torpedoes and which utilizes current torpedo components.

These objects are accomplished with the present invention by providing articulation units located between the major sections, i.e., tail cone, fuel tank and payload sections, of an existing torpedo. Each articulation unit consists of two bulkheads connected by a spherical joint. The bulkheads are connected to adjacent torpedo sections and the spherical joint between the bulkheads allows the angular rotation of one torpedo section with respect to the other. Each articulation unit has a number of hydraulic actuators which control the angular rotation at the spherical joint. The articulation units have flexible cover membranes over the space between the bulkheads so as to present a smooth surface to the surrounding medium and hence not appreciably increase the drag on the torpedo. By selectively activating the hydraulic actuators, the torpedo can be made to bend and thus maneuver through the water.

A more complete understanding of the invention and many of the attendant advantages thereto will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein corresponding reference characters indicate corresponding parts throughout the several views of the drawings and wherein:

FIG. 1 shows a side view of a standard torpedo;

FIG. 2 shows the torpedo of FIG. 1 fitted with the articulation units of the present invention;

FIG. 3 shows a cross sectional view of an articulation unit taken along the axis X--X of the torpedo; and

FIG. 4 shows a view of a torpedo with the actuators of the articulation unit activated for turning the torpedo.

Referring now to FIG. 1, there is shown a side view of a prior art torpedo 10. Torpedo 10 is of standard elongated cylindrical design having four sections: a control section 10a; a payload section 10b; a fuel tank section 10c; and a tail cone section 10d. The sections are connected by means of joint bands 12. Tail cone section 10d contains the propulsion unit (not shown) for the torpedo which turns the propellers 14 shown as dashed beneath shroud 16. Tail cone section 10d further includes damping vanes 18 and turning fins 20. Damping vanes 18 serve to prevent rolling of the torpedo about its longitudinal axis X--X. The direction of travel of torpedo 10 is determined by the orientation of turning fins 20 as controlled from control section 10a in a manner well known in the torpedo art.

Referring now to FIG. 2, torpedo 10 is shown with articulation units 22 fitted between the sections 10a-d. The articulation units 22 are connected between the sections by means of an additional joint band 12, such that a joint between sections of the torpedo now includes a joint band 12 on either side of articulation unit 22. The articulation units 22 are used to control the direction of travel of the torpedo such that turning fins 20 indicated in FIG. 1 are no longer necessary and have not been shown in FIG. 2. It will be appreciated that turning fins 20 could remain to provide redundant directional control of torpedo 10. Referring now to FIG. 3, there is shown a cross section of an articulation unit 22 installed between two sections 10a and 10b of torpedo 10, taken along the axis X--X. Only a portion of torpedo sections 10a and 10b have been shown and it will be understood that articulation unit 22 may be installed between any two torpedo sections. Additionally, in the preferred embodiment shown, the features of articulation unit 22 are seen to be symmetrical about the axis X--X. For clarity, reference characters for some features have been indicated on only one side of axis X--X. Articulation unit 22 has a forward bulkhead 24 and an aft bulkhead 26 which are formed to mate with torpedo sections 10a and 10b, respectively, and with joint bands 12. Bulkheads 24 and 26 are circular in shape to conform with the shape of torpedo 10. Joint bands 12 are seen to be ring members which circumscribe torpedo 10. Each joint band 12 has two raised bosses 12a which mate with grooves 10f in torpedo sections 10a and 10b and with grooves 28 of bulkheads 24 and 26. A flexible cover membrane 30 circumscribes the space between bulkheads 24 and 26 to maintain the hydraulically smooth surface of torpedo 10. Membrane 30 is held in place by two retainer rings 32 which fit into respective grooves 34 in bulkheads 24 and 26. Standard o-ring seals 10g are provided to ensure the joints are watertight.

Pivot sphere 36 is securely attached to the center of forward bulkhead 24 facing aft bulkhead 26. In the preferred embodiment shown, a portion of sphere 36 is truncated to form base 36a which is attached to forward bulkhead 24 by means of screws, designated by dashed lines 36b. Aft bulkhead 26 is formed with pivot receptor 38 at its center. Receptor 38 defines a partial, concave, spherical surface matched to pivot sphere 36. Receptor 38 is fabricated in top and bottom portions, 38a and 38b, for assembly purposes. Pivot o-ring seals 38c ensure a tight seal of sphere 36 against receptor 38 while allowing sphere 36 to rotate angularly within receptor 38. To control the angular rotation of the sphere, hydraulic actuators 40 are radially spaced equally about sphere 36. In the preferred embodiment of FIG. 3, two of four hydraulic actuators 40 are shown. Clamps 42 are used to attach cylinder end 40a and piston end 40b to bulkhead 24 and 26, respectively. Together with ball ends 40c of hydraulic actuators 40 and spherical indents 24a and 26a of bulkheads 24 and 26, respectively, clamps 42 form a ball joint attachment of hydraulic actuators 40 to bulkheads 24 and 26. This attachment allows rotation of hydraulic actuators 40 while sphere 36 is rotated angularly. Hydraulic actuators 40 are fitted with well known linear position sensors 40d which provide a signal via leads 44 to the control system of torpedo 10 (not shown) corresponding to the amount of extension of piston end 40b. The control system acts to decrease or increase pressure in hydraulic lines 46 attached to cylinder end 40a of actuators 40 to move piston end 40b into or out of cylinder end 40a in a manner well known in the hydraulic actuator art. Bore 36c in sphere 36 allows for passage of hydraulic lines 46, electrical leads 44 and various other cabling, denoted as 48, between the various sections of torpedo 10.

In assembling articulation unit 22, pivot sphere 36 is first placed within bottom portion 38b of receptor 38. Top portion 38a is then placed over sphere 36 and firmly attached to bottom portion 38b by means of receptor screws, designated by dashed lines 38d. Forward bulkhead 24 is then attached to sphere 36 and actuators 40 are attached between bulkheads 24 and 26. The articulation unit can then be placed between two of the torpedo sections and joint bands 12 attached. Connections are then made to leads 44 and hydraulic lines 46 and leads 44, lines 46 and cabling 48 are passed through bore 36d. Finally membrane covers 30 are installed and the assembly is complete.

Referring now to FIG. 4, torpedo 10 of FIG. 2 is shown in a turning position. To accomplish this maneuver, the control system of torpedo 10 would cause the extension of hydraulic actuators on the outward side of the curved trajectory shown and the retraction of hydraulic cylinders on the inward side of the curved trajectory. Note that membrane covers 30 have stretched or contracted to accommodate the movement of articulation units 22, thus closely maintaining the cylindrical shape of torpedo 10.

What has thus been described is a system of articulation units inserted between sections of a standard torpedo. The articulation units consist of two bulkheads connected by a spherical joint allowing angular rotation of the joint. Hydraulic actuators are radially spaced around the joint. Selective activation of the actuators by the torpedo control system provides for controlled bending of the torpedo about its longitudinal axis. As the torpedo is bent about the articulation units, the torpedo is turned in the direction of the bend, thus providing a highly maneuverable torpedo without the need for steering fins. The articulation units have flexible cover membranes over the space between the bulkheads so as to present a smooth surface to the surrounding medium and hence not appreciably increase the drag on the torpedo.

Obviously many modifications and variations of the present invention may become apparent in light of the above teachings. For example, the exact shapes and configurations of the particular components shown can be changed to suit manufacturing and assembly considerations. The number of actuators can be varied to suit the requirements. Additionally, the hydraulic actuators can be replaced with any known extension and retraction means, such as jack screws with small electric servo motors. Further, with minor modifications, the spherical joint could be replaced with any well known universal type joint.

In light of the above, it is therefore understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.