WO2019229633A1

WO2019229633A1 - An autonomous surface vessel

Info

Publication number: WO2019229633A1
Application number: PCT/IB2019/054383
Authority: WO
Inventors: Maitrai MAKA
Original assignee: Rekise Marine Pvt. Ltd.
Priority date: 2018-05-27
Filing date: 2019-05-27
Publication date: 2019-12-05

Abstract

An autonomous surface vessel is provided. The autonomous surface vessel includes a mono hull to provide a self-righting ability for the autonomous surface vessel. The autonomous surface vessel also includes a gyroscopic stabiliser configured to provide a counter moment with respect to wave induced moment of waterbody to improve the sea keeping performance of the autonomous surface vessel. The autonomous surface vessel also includes at least one battery configured to enable propulsion of the autonomous surface vessel. The autonomous surface vessel is sealed to prevent the autonomous surface vessel from water ingress upon accidental submergence.

Description

“AN AUTONOMOUS SURFACE VESSEL”

FIELD OF INVENTION

[1] Embodiments of a present disclosure relates to a marine vessel, and more particularly to a mono-hull autonomous surface vessel.

BACKGROUND

[2] Marine vessels also known as watercrafts or waterborne vessels are vehicles used in water, including ships, boats, submarines, hovercrafts, etc. Marine vessel configurations and displacements vary significantly based on their intended utility. For example, a racing yacht, a container ship, an oceanographic research ship and an aircraft carrier have distinct designs. Unmanned/ Autonomous surface vessels (US Vs/AS Vs) are vehicles that operate on the surface of the water without a crew onboard. Recent advancements in computing, perception sensor technologies and wireless communications have made this possible.

[3] Today, USVs/ASVs are being employed in oceanography, patrolling and surveying due to their economic advantages over manned marine vessels. USVs/ASVs when designed for unmanned operations exclusively by eliminating human spaces and support systems have smaller displacements. This smaller displacement coupled with fewer support systems result in significant capital and operational savings over manned marine vessels. However, larger displacement marine vessel tends to have better sea-keeping ability. As a vessel gets smaller the size of the waves relative to the size of the vessel increases; this coupled with the lower inertial of a smaller displacement vessel results in poor sea-keeping ability. For such small displacement USVs/ASVs operating in open waters, it can even become challenging to maintain a straight line of travel due to excessive motions. As a direct consequence, USVs/ASVs with small displacements (< 500Kgs) have been limited to protected waters (lakes, rivers, dams etc.) due to their lack of sea-keeping ability, a critical mission requirement for all marine operations. [4] For example, while conducting a bathymetric survey using single narrow beam sound waves emitted from a vessel to detect underwater features, it is imperative that the beam is always pointing downwards so it does not miss the submerged feature which could be a potential navigational hazard to other marine vessels. A small displacement USV/ASV has a higher probability of missing a feature due to its excess roll and pitch motions than a larger displacement vessel (manned or unmanned). A missed feature could result in the accidental grounding of a vessel resulting in serious damages (property and life). This fear of missing features due to lack of proper sea keeping ability of small US Vs/AS Vs has resulted in the poor adoption of the technology by the industry in navigational channel surveying.

[5] Currently, although some design features have been employed to increase the stability and sea-keeping ability of the vessels, they have not been adequate for open ocean missions. For example, multi-hull designs such as catamarans and trimarans provide greater initial stability for the USVs/ASVs. However, small displacement vessels have a higher probability of capsizing and being submerged underwater due to waves. Once capsized these multi-hull vessels have poor self- righting ability. More traditional stabilisation systems like the fin stabilisers have not been adopted due to the added complexity and limited space in the small displacement USVs. The lack of good sea-keeping ability and survivability have been a hindrance in the adoption of these AS Vs/US Vs for open ocean missions.

[6] Hence, there is a need for an improved autonomous surface vessel of lighter displacement such as the mono-hull autonomous surface vessel with a stabilising system in order to address the aforementioned issues.

BRIEF DESCRIPTION

[7] In accordance with an embodiment of the disclosure, an autonomous surface vessel is disclosed. The autonomous surface vessel includes a mono hull to provide a self-righting ability for the autonomous surface vessel. The autonomous surface vessel also includes a gyroscopic stabiliser configured to provide a counter moment with respect to wave induced moment movement of waterbody to improve the sea keeping performance of the autonomous surface vessel. The autonomous surface vessel also includes at least one battery configured to enable propulsion of the autonomous surface vessel. The unmanned surface vessel is hermetically sealed to secure the autonomous surface vessel (10) from water ingress even upon accidental submergence.

[8] In accordance with another embodiment, the autonomous surface vessel further includes one or more bow thrusters mechanically coupled to a front end at a bottom of the mono hull, wherein the one or more bow thrusters are placed within the mono hull below a load waterline. The one or more bow thrusters is configured to propel the autonomous surface vessel laterally. The autonomous surface vessel further includes one or more stem thrusters mechanically coupled to a rear end of the mono hull and submerged below the load waterline. The one or more stem thrusters is configured to propel the autonomous surface vessel.

[9] To further clarify the advantages and features of the present disclosure, a more particular description of the disclosure will follow by reference to specific embodiments thereof, which are illustrated in the appended figures. It is to be appreciated that these figures depict only typical embodiments of the disclosure and are therefore not to be considered limiting in scope. The disclosure will be described and explained with additional specificity and detail with the appended figures.

BRIEF DESCRIPTION OF THE DRAWINGS

[10] The disclosure will be described and explained with additional specificity and detail with the accompanying figures in which:

[11] FIG. 1 is a projected view of an autonomous surface vessel in accordance with an embodiment of the present disclosure;

[12] FIG. 2 is a projected top view of an embodiment of an autonomous surface vessel of FIG. 1 in accordance with an embodiment of the present disclosure;

[13] FIG. 3 is a projected side view of an embodiment of the autonomous surface vessel of FIG. 1 in accordance with an embodiment of the present disclosure;

[14] FIG. 4 is a projected side view of another embodiment of the autonomous surface vessel of FIG. 1 in accordance with an embodiment of the present disclosure; [15] FIG. 5 is a projected side view of yet another embodiment of the autonomous surface vessel of FIG. 1 representing a deployed position of the ASV in accordance with an embodiment of the present disclosure; and

[16] FIG. 6 is a projected side view of yet another embodiment of the autonomous surface vessel of FIG. 1 in accordance with an embodiment of the present disclosure.

[17] Further, those skilled in the art will appreciate that elements in the figures are illustrated for simplicity and may not have necessarily been drawn to scale. Furthermore, in terms of the construction of the device, one or more components of the device may have been represented in the figures by conventional symbols, and the figures may show only those specific details that are pertinent to understanding the embodiments of the present disclosure so as not to obscure the figures with details that will be readily apparent to those skilled in the art having the benefit of the description herein.

DETAILED DESCRIPTION

[18] For the purpose of promoting an understanding of the principles of the disclosure, reference will now be made to the embodiment illustrated in the figures and specific language will be used to describe them. It will nevertheless be understood that no limitation of the scope of the disclosure is thereby intended. Such alterations and further modifications in the illustrated system, and such further applications of the principles of the disclosure as would normally occur to those skilled in the art are to be construed as being within the scope of the present disclosure.

[19] The terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process or method that comprises a list of steps does not include only those steps but may include other steps not expressly listed or inherent to such a process or method. Similarly, one or more devices or sub-systems or elements or structures or components preceded by "comprises... a" does not, without more constraints, preclude the existence of other devices, sub-systems, elements, structures, components, additional devices, additional sub-systems, additional elements, additional structures or additional components. Appearances of the phrase "in an embodiment", "in another embodiment" and similar language throughout this specification may, but not necessarily do, all refer to the same embodiment.

[20] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this disclosure belongs. The system, methods, and examples provided herein are only illustrative and not intended to be limiting.

[21] In the following specification and the claims, reference will be made to a number of terms, which shall be defined to have the following meanings. The singular forms“a”,“an”, and“the” include plural references unless the context clearly dictates otherwise.

[22] Embodiments of the present disclosure relate to an autonomous surface vessel. The autonomous surface vessel includes a mono hull to provide a self-righting ability for the autonomous surface vessel. The autonomous surface vessel also includes a gyroscopic stabiliser configured to provide a counter moment with respect to wave induced moment of waterbody to improve the sea keeping performance of the autonomous surface vessel. The autonomous surface vessel also includes at least one battery configured to enable propulsion of the autonomous surface vessel. The unmanned surface vessel is hermetically sealed to secure the autonomous surface vessel (10) from water ingress even upon accidental submergence.

[23] FIG. 1 is a projected view of an autonomous surface vessel (ASV) (10) in accordance with an embodiment of the present disclosure. As used herein, the term ‘autonomous surface vessel’ (10) also known as unmanned surface vessel is defined as a type of vehicle which operates on a surface of water with or without a crew onboard. Moreover, the ASV as described in the present disclosure refers to a vessel having no provision for a person/ crew to be physically present on the vessel.

[24] Furthermore, the ASV (10) includes a mono hull (20) configured to provide a self-righting ability for the ASV (10). As used herein, the term‘hull’ is defined as a main body of the ASV (10) which includes a keel, sides and a deck of the ASV (10). Further, the term‘mono hull’ (20) is defined as the ASV (10) having a single hull. Also, the term‘self-righting ability’ is defined as an ability of a vessel to return to an upright position upon being capsized without external intervention. In one specific embodiment, a precession axis of the gyroscopic stabiliser (not shown in FIG.1-7) may be locked on capsize to disable the stabilising system momentarily until self-righting occurs. In such an embodiment, the gyroscopic stabiliser may be reactivated by unlocking the precession axis to improve the stability of the ASV (10).

[25] In one exemplary embodiment, the mono hull may be a slender shaped mono hull. As used herein, the term“slender shaped mono hull” may refer to a type of mono hull comprising long length to breadth ratio.

[26] The ASV (10) also includes the gyroscopic stabiliser. The gyroscopic stabiliser is configured to provide a counter moment with respect to wave induced moment of waterbody to improve the sea keeping performance of the autonomous surface vessel (10) by reducing roll and/or pitch motion of the autonomous surface vessel (10). More specifically, the gyroscopic stabiliser is configured to nullify an oscillatory motion of the vessel (10) to increase stability of the vessel. In one embodiment, the gyroscopic stabiliser may be configured to provide the counter moment across at least one of a roll axis and a pitch axis.

[27] Furthermore, the ASV (10) also includes at least one battery configured to enable propulsion of the autonomous surface vessel (10). In one embodiment, the ASV (10) may further include one or more bow thrusters (40) (as shown in FIG. 4). The one or more bow thrusters (40) are placed within the mono hull (20) and below a water line (35). As used herein, the term“bow thrusters” (40) is defined as a type of thruster which is mounted in a bow of the vessel. More specifically, the one or more bow thrusters (40) are placed within the bow of the mono hull (20) of the ASV (10). As used herein, the term“water line” may be defined as a level which is reached by the water on sides of the vessel in any specific load case.

[28] Further, the one or more bow thrusters (40) is configured to propel the autonomous surface vessel (10). In one specific embodiment, the one or more bow thrusters (40) may be configured to generate lateral thrust for the ASV (10). In addition, the one or more bow thrusters (40) may also generate a moment which will tend to rotate the ASV (10) for manoeuvring.

[29] In one exemplary embodiment, the one or more bow thrusters (40) may be operatively coupled to at least one of a screw propeller and a waterjet propeller. As used herein, the term‘ screw propeller’ is defined as a type of propeller having multiple blades fastened around a conical base to transmit power by converting rotational motion into thrust. Also, the term‘waterjet propeller’ is defined as a marine system which creates a jet of water for propulsion. In such embodiment, the one or more bow thrusters (40) may be configured to steer the ASV (10) for manoeuvring.

[30] In another embodiment, the ASV (10) may further include one or more stern thrusters (50) (as shown in FIG. 1-7) mechanically coupled to a rear end of the mono hull (20) and is positioned to be submerged inside the waterbody and is submerged from below the keel plane (55), wherein the vertical placement of the thruster may vary in depth with respect to the keel plane (55). In such embodiment, the one or more stem thrusters (50) may be mechanically coupled to the mono hull (20) via a pre defined section (60) (as shown in FIG. 1-5) extending from the body of the mono hull (20). In one embodiment, the pre-defined section (60) may be having a shape of an inverted Ί’ section comprising a vertical subsection and a horizontal subsection. The horizontal subsection may be attached to the vertical subsection at a right angle, wherein a centre of the horizontal subsection may be coupled to the vertical section. Further, at least one of the one or more stem thrusters (50) may be coupled at each end of the horizontal subsection. The horizontal and vertical subsections may be streamlined to reduce drag.

[31] In another such embodiment, the one or more stem thrusters (50) may be coupled to two individual vertical subsections attached to the mono hull (20) from a top section and may be positioned to be submerged inside the waterbody. In one embodiment at least one of the one or more stem thrusters (50) may be coupled to a rear end of the mono hull (20) and submerged below the waterline.

[32] In another embodiment, the ASV may include a mast and a stern thruster assembly (120) (as shown in FIG. 5 and 6) which may be foldable.

[33] Furthermore, in one exemplary embodiment, the autonomous surface vessel (10) may further include at least one charging port placed on top of a mast (120), wherein the charging port is hermetically sealed (120). As used herein, the term“mast” is defined as a tall upright slender structure on a marine vessel for carrying one or more components. Further, at least one charging port is configured to enable charging of the at least one battery. In one specific embodiment, the mast (120) may be a foldable mast (120). In such embodiment, the one or more stem thrusters (50) which may be coupled to the pre-defined streamlined section (60) may be folded which may enable the storage of the ASV on the keel plane (55) (as shown in FIG. 6 and 7).

[34] In addition, the mast (120) may be provided with a stand (140) in order to support the mast (120) upon being folded (as shown in FIG. 7). The lifting lug (130) may be configured for vessel deployment and recovery.

[35] Furthermore, the autonomous surface vessel (10) is hermetically sealed to secure the autonomous surface vessel (10) and to prevent accidental water ingress. In one embodiment, the ASV (10) may be sealed to enable the ASV (10) to withstand the pressure and water ingress upon being submerged within the waterbody. In such embodiment, the submergence may be up to 20 meters.

[36] In one exemplary embodiment (as shown in FIG. 3 and FIG. 5), a payload may be placed through the payload hatch (80) located on the deck (70) of the ASV (10). Also, the ASV (10) may further include a submersible emergency switch (90) which may be fixed on the deck (70) of the vessel.

[37] In another exemplary embodiment (as shown in FIG. 2 and FIG. 4), the ASV (10) may include a moon pool (100), wherein the moon pool (100) may be configured to enable mounting of one or more sensors and one of an echosounder which may be submerged within the waterbody. Also, the one or more components, wherein the one or more components may correspond to one or more electrical components may be placed within an electronic hatch (110), wherein the electronic hatch (110) may be located on the deck (70) of the vessel.

[38] Various embodiments of the present disclosure enable the ASV to use the gyroscopic stabiliser to improve the sea-keeping ability and survivability of the ASV. In addition, the overall cost of the autonomous surface vehicle is reduced as the displacement of the vessel is made small and is capped between 30kgs to 500kgs. Also, the displacement of the vessel is reduced by eliminating an additional space for occupation of a user, thereby making the vessel remotely controlled /autonomous and hence more cost effective to operate. [39] Furthermore, as the size of the autonomous surface vessel is reduced in comparison with the manned vessel, this further reduces consumption of fuel which adds in lowering the overall lifetime operating cost of the vessel. Furthermore, due to the use of the gyroscope, seakeeping ability of the vessel is well maintained for any level/ size of waves created in a water body.

[40] In addition, due to the adaptation of the electric propulsion means, the entire ASV is hermetically sealed, which in turn eliminates the need of an air inlet and an exhaust outlet. The sealing of the vessel prevents water ingress during an accidental capsize or submergence scenario. Because any water intake can affect the stability characteristics of the vessel, this complements the self-righting ability by ensuring the stability characteristics of the ASV remain unaltered during such worst-case scenarios. Hermetic sealing also enables the use of commercial off the shelf electronics and other systems in the vessel instead of expensive purpose-built marine systems with built in ingress protection.

[41] Moreover, maintenance of the vessel is easier as there is no internal combustion (IC) engine. Electric permanent magnet motor being employed for propulsion have more sparse service requirements. The ASV can use either a passive/precession axis is controlled by the dynamics of the system) or active (precession axis is actuated) gyroscopic stabilisation system.

[42] Furthermore, because of the small draft of the vessel (<25cm), if the stern thrusters were placed just below the keel plane like in a traditional marine vessel, the stem thrusters would emerge out in waves. Hence, the stern propellers are submerged much farther down the waterline to ensure they do not emerge out of the water due to the waves in the ocean or the stem wave caused by the forward motion of the vessel. Because this results in stem thruster assembly protruding below the keel plane, a mechanism has been provided to rotate the stern thruster assembly by 180 degrees for stowage at level with the keel plane when the vessel is out of the water.

[43] Also, since the bow thrusters are also used only sparsely, their frequent emergence out of the water will not affect the efficiency of the vessel noticeably. Also since the freeboard of the vessel is going to be small (<0.75m), accidental wetting of the charging port is prevented by placing it on the mast. If it were placed on the deck instead, there is a rather high probability of it getting wet by waves when the charging port seal is opened to plug in an external power supply. In addition, the option of folding the one or more stem thrusters and the mast enables the storage of the vessel on the keel plane which helps in reducing the overall space requirement of the vessel.

[44] The sea keeping performance of a low displacement self-righting mono hulled autonomous surface vessel is improved by the incorporation of a gyroscopic stabilisation system. Use of electrical propulsion system using batteries instead of an internal combustion engine and fuel enables the vessel to be sealed hermetically. The sealing which prevents water ingress, compliments the self-righting ability of the autonomous surface vessel and enables the use of cheaper commercial off the shelf electronics. A bow thruster improves the manoeuvrability considerably. Because it is sparsely used for steering on a straight course, its emergence out of water does not affect the efficiency of the autonomous surface vessel. Both the rear thrusters and the mast are configured to be foldable to reduce the stowage area without affecting the autonomous surface vessel performance. Accidental shorting of the charging connector is prevented by placing it well above the waterline on the mast.

[45] While specific language has been used to describe the disclosure, any limitations arising on account of the same are not intended. As would be apparent to a person skilled in the art, various working modifications may be made to the method in order to implement the inventive concept as taught herein.

[46] The figures and the foregoing description give examples of embodiments. Those skilled in the art will appreciate that one or more of the described elements may be combined into a single functional element. Alternatively, certain elements may be split into multiple functional elements. Elements from one embodiment may be added to another embodiment. For example, order of processes described herein may be changed and are not limited to the manner described herein. Moreover, the actions of any flow diagram need not be implemented in the order shown; nor do all of the acts need to be necessarily performed. Also, those acts that are not dependant on other acts may be performed in parallel with the other acts. The scope of embodiments is by no means limited by these specific examples.

Claims

WE CLAIM:

1. An autonomous surface vessel (10) comprising: a mono hull (20) configured to provide a self-righting ability for the autonomous surface vessel; a gyroscopic stabiliser configured to provide a counter moment with respect to wave induced moment of waterbody to keep the autonomous surface vessel (10) for sea keeping performance; and at least one battery configured to enable propulsion of the autonomous surface vessel (10), wherein the autonomous surface vessel (10) is hermetically sealed to secure the autonomous surface vessel (10) from water ingress even upon accidental submergence.

2. The autonomous surface vessel (10) as claimed in claim 1, wherein the mono hull (20) comprises a slender shaped mono hull.

3. The autonomous surface vessel (10) as claimed in claim 1, wherein the autonomous surface vehicle (10) comprising a displacement of about 30 kilograms to 500 kilograms.

4. The autonomous surface vessel (10) as claimed in claim 1, further comprising: one or more bow thrusters (40) mechanically coupled to a front end at a bottom of the mono hull (20) below a water line (35), wherein the one or more bow thrusters (10) are placed within the mono hull (20) and below a waterline, wherein the one or more bow thrusters (40) is configured to propel the autonomous surface vessel (10) laterally; and one or more stern thrusters (50) mechanically coupled to a rear end at a top of the mono hull (20) and submerged below the waterline, the one or more stern thrusters (50) is positioned to be submerged inside the waterbody and is submerged from below the keel plane (55), wherein the one or more stem thrusters (50) is configured to propel the autonomous surface vessel (10).

5. The autonomous surface vessel (10) as claimed in claim 4, wherein the one or more stem thmsters (50) are mechanically coupled to the mono hull (20) via a pre-defined streamlined section (60) extending from the body of the mono hull (20).

6. The autonomous surface vessel (10) as claimed in claim 4, wherein least one of the one or more bow thrusters (40) and the one or more stem thmsters (50) is further configured to generate a transverse movement of the autonomous surface vessel (10) to steer the autonomous surface vessel (10) for manoeuvring.

7. The autonomous surface vessel (10) as claimed in claim 1, wherein the autonomous surface vessel (10) comprises a foldable mast and a stern thmster assembly.

8. The autonomous surface vessel (10) as claimed in claim 1, further comprising at least one charging port placed on a mast, wherein an access of the charging port is hermetically sealed on the mast, wherein the at least one charging port is configured to enable charging of the at least one battery.

9. The autonomous surface vessel (10) as claimed in claim 1, wherein the gyroscopic stabilisation system will be automatically switched off in the case of a capsize scenario until self-righting happens.