Description:FORM 2

THE PATENTS ACT, 1970
[39 OF 1970]
&
THE PATENTS RULES, 2003

COMPLETE SPECIFICATION
[See Section 10, Rule 13]

A DYNAMICALLY STABLE AUTONOMOUS UNDERWATER VEHICLE (AUV) WITH ENHANCED THERMAL PERFORMANCE
BY

PLANYS TECHNOLOGIES PVT. LTD INCORPORATED AS A PRIVATE LIMITED COMPANY RECOGNIZED AS A STARTUP BY THE DEPARTMENT FOR PROMOTION OF INDUSTRY AND INTERNAL TRADE, WHOSE ADDRESS IS NO. 5 JAYA NAGAR EXTENSION, BALAJI NAGAR MAIN ROAD, G.K. AVENUE, PUZHUTHIVAKKAM, CHENNAI 600091, TAMIL NADU, INDIA

THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED
 
FIELD OF THE INVENTION
The present invention relates to an autonomous underwater vehicle (AUV).
BACKGROUND OF THE INVENTION
Autonomous underwater vehicles (AUVs) are pre-programmed underwater vehicles which navigate a pre-fed path collecting data from several on-board sensors and payloads while avoiding any obstacles along the way. These underwater vehicles differ from remotely operated underwater vehicles (ROVs) in terms of mode of operation and their shapes. ROVs are required to operate in tight spaces and in areas which require close inspections, therefore requiring movement in many degrees of freedom. Whereas AUVs are often made with a long torpedo shape to minimize drag as they spend their time most often travelling a straight-line path with a constant speed. Accordingly, in AUVs, propulsion is offered by typically a single rotary blade-type thruster in addition to control fins to steer directions, thus the degrees of freedom in AUV are limited.
AUVs are available in the market with different shapes and sizes. Usually, AUVs are operated in a large area, usually in the sea or an ocean and sometimes in a large lake. The selection in the shape and size of the AUVs depends on the type of the application, programs, or studies to be performed. Larger/heavier AUVs performs well in rough underwater conditions due to high currents and swells due to their large size, mass and power capacity. Smaller/lighter AUVs are desired for many applications due to their ease of use, cost savings in logistics, etc. However, smaller AUVs cannot be used in rough waters due to their low mass and power. Therefore, usage of a smaller AUVs with an ability to operate in the rough waters would be of good value.
Further, AUVs in the market have multiple enclosures to house the electronics unit, battery unit, sensors and payloads separately. These enclosures are typically held together in a frame or a hull providing protection and mechanical rigidity for the whole vehicle. Having such multiple enclosures lead to increased weight and increases the risk of leakages through multiple sealing surfaces. Therefore, it is desired to have minimal enclosures and therefore, minimal sealing surfaces. Additional, using metallic enclosures for the AUVs increases the weight of the AUV.
On the other hand, the use of non-metallic enclosures like composite materials in the field of underwater vehicle is desired as they are light in weight, easy to handle, and their low logistic cost and maintenance cost. However, the performance of a light weight AUV in water would be compromised in rough waters and using non-metallic enclosures for the AUVs leads to issues in thermal management and therefore remains as a challenge in the industry.
Another challenge faced in the industry is with respect to fast charging and high discharge rate batteries. The major challenge associated with fast charging is with the difficulties faced by management of the thermal aspects of the battery enclosure. Battery enclosures are usually metallic enclosures, in which the battery cells of lithium ion or nickel cadmium cells are packed together in a closed pack arrangement. These cells generate heat as they are charged or discharged and sinking of heat to the outside medium through the metallic enclosure. These metallic enclosures are often enclosed by a buoyancy foam or a body panel of the vehicle. This acts as a compromise on the cooling ability of the battery enclosure and would lead to issues in thermal management.
Therefore, there is a need in the art to provide an AUV that overcomes all the above identified problems.
SUMMARY OF THE INVENTION
An objective of the present invention is to provide an AUV with an ability to operate in the rough waters. Another objective of the present invention is to provide the AUV to facilitate movement in many degrees of freedom. Another objective of the present invention is to provide the AUV with minimal enclosures and therefore, minimal sealing surfaces. Another objective of the present invention is to provide the AUV with light weight enclosures without compromising on the cooling ability.
In an embodiment, the present invention provides an autonomous underwater vehicle (AUV) comprising: a frame; a communication unit configured on a front end of the frame; a battery unit centrally configured on the frame; a steering unit configured on a rear end of the frame; a first cavity formed between the communication unit and the battery unit; a second cavity formed between the battery unit and the steering unit; an enclosure to seal the first cavity and the second cavity; at least a flood port configured in a first side of the enclosure, each flood port is in connection with at least one of the first cavity and the second cavity; at least an air vent configured in a second side of the enclosure, the second side is configured opposite to the first side and each air vent is in connection with at least one of the first cavity and the second cavity; wherein when water enter the cavities through the flood ports, the air vents release air inside the cavities adding mass to the AUV thereby enhancing the dynamic stability of the AUV against external perturbations..
According to an embodiment of the present invention, the frame further comprises a pair of heave thruster and a pair of surge thruster, the heave thrusters are vertically positioned on the frame and each heave thruster is configured to pass through at least one of the first cavity and the second cavity, the surge thrusters are mounted laterally on the frame in juxtaposition to the battery unit, wherein the thrusters configured to facilitate water flow for convective cooling of the battery unit.
According to an embodiment of the present invention, the cavities enhance dynamic stability of the AUV by adjusting mass moment of inertia of the AUV.
According to an embodiment of the present invention, the mass moment of inertia of the AUV is directly proportional to the product of mass of water in the first cavity and square of a distance of the first cavity from a rotational axis (Y or Z) of the AUV.
According to an embodiment of the present invention, the mass moment of inertia of the AUV is directly proportional to the product of mass of water in the second cavity and square of a distance of the second cavity from a rotational axis (Y or Z) of the AUV.
According to an embodiment of the present invention, the communication unit includes a computing module, a data acquisition module, a camera unit and a networking module.
According to an embodiment of the present invention, the battery unit includes at least one battery, a battery management system (BMS), a computing module, a communication module, at least one electric drive, at least one electric motor, at least one power convertor.
According to an embodiment of the present invention, the steering unit includes at least a steering gear, a control equipment, a rudder carrier, a rudder and a rudder horn or a combination thereof.
According to an embodiment of the present invention, the cavities are in contact with the battery unit to facilitate convective cooling of the battery unit.
According to an embodiment of the present invention, each of the air vents and the flood ports has a flow-controlled valve, the flow-controlled valves are actuated by a controller.
According to an embodiment of the present invention, the controller processes a feedback received from at least one sensor and actuates at least one of the flow-controlled valves for controlling the mass of water in the cavities.
According to an embodiment of the present invention, the sensors include and not limited to at least one water level sensor configured in each cavity, at least one air pressure sensor configured in each cavity, at least one water pressure sensor configured in each cavity, at least one gyro sensor configured in the frame, at least one accelerometer configured in the frame, at least one depth sensor configured on the enclosure and at least one water pressure sensor configured on the enclosure.
In this respect, it is to be understood that the present AUV is not limited in its applications to the details of construction and arrangements of the components set forth in the following description or illustration. Those skilled in the art will appreciate that the concept of this disclosure may be readily utilized as a basis for the design of other structures, methods, and systems for carrying out the several purposes of the AUV.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are included to provide a further understanding of the invention are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and together with the description serve to explain the principles of the invention. They are meant to be exemplary illustrations provided to enable persons skilled in the art to practice the disclosure.
Figure 1 shows a side view of an autonomous underwater vehicle (AUV) according to an embodiment of the present invention;
Figure 2 shows an isometric view of the AUV without an enclosure according to an embodiment of the present invention;
Figure 3 shows a schematic isometric view of the AUV according to an embodiment of the present invention;
Figure 4 shows a schematic top view of the AUV according to an embodiment of the present invention;
Figure 5 shows a schematic back view of the AUV according to an embodiment of the present invention;
Figure 6 shows a schematic front view of the AUV according to an embodiment of the present invention;
Figure 7 shows a schematic bottom view of the AUV according to an embodiment of the present invention;
Figure 8 shows a schematic side view of the AUV according to an embodiment of the present invention;
Figure 9 shows a side view of the AUV according to an embodiment of the present invention;
Figure 10 shows a top view of the AUV according to an embodiment of the present invention; and
Figure 11 in an isometric view of the AUV without an enclosure to illustrate a first cavity, a second cavity and rotational axes according to an embodiment of the present invention.
Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures.
DETAILED DESCRIPTION OF THE INVENTION
The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of the invention as defined by the description. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.
The terms and words used in the following description are not limited to the bibliographical meanings but are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of the present invention is provided for illustration purpose only.
It is to be understood that the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise.
Figure 1-10 shows an autonomous underwater vehicle (AUV) in accordance with the present invention. The AUV (100) comprises a frame (101). The frame (101) is the primary structure in the AUV (100), providing support to all mounted entities, components or elements. A communication unit (102) is mounted on a front end of the frame (101). In an embodiment, the communication unit (102) includes but not limited to a computing module, a data acquisition module, a camera unit and a networking module, etc. A battery unit (103) is centrally mounted on the frame (101). In an embodiment, the battery unit (103) includes but not limited to at least one battery, a battery management system (BMS), a computing module, a communication module, at least one electric drive, at least one electric motor and at least one power convertor, etc. A steering unit (104) is mounted on a rear end of the frame (101). In an embodiment, the steering unit (104) includes but not limited to at least a steering gear, a control equipment, a rudder carrier, a rudder and a rudder horn or a combination thereof. In an embodiment, the frame (101) has a circular arc design on its front end and rear end to reduce the underwater resistance of the AUV (100).
As seen in figure 2, a first cavity (105) is formed in a space or gap defined between the communication unit (102) and the battery unit (103). Similarly, a second cavity (106) is formed in a space or gap defined between the battery unit (103) and the steering unit (104). In an embodiment, the first cavity (105) and the second cavity (106) are not fluidically connected to each other. At least one enclosure (107) is provided for sealing each of the first cavity (105) and the second cavity (106). At least a flood port is configured in a first side of the enclosure (107), each of the flood port is in fluidic connection with at least one of the first cavity (105) and the second cavity (106). At least an air vent formed in a second side of the enclosure (107), the second side is configured opposite to the first side and each of the air vent is in fluidic connection with at least one of the first cavity (105) and the second cavity (106). In an embodiment, the first side is the bottom surface of the AUV (100), and the second side is the upper surface of the AUV (100). In an embodiment, the flood ports are formed at a bottom most part of the enclosure (107) and the air vent are formed at an upper most part of the enclosure (107). During operation, when the AUV (100) is released or launched in a water body i.e. a river, dam, lake, sea, ocean and the like, the water of the water body starts to enter the cavities (105, 106) through the flood ports and thus forcing the air present in the cavities (105, 106) to flow out through the air vents. In an embodiment, the air vent has a one-way valve such that the air inside the cavity (105, 106) is allowed to flow outside the cavity (105, 106) through the one-way valve of the air vent and restricts the flow of air or water to enter the cavity (105, 106) through the air vent. The water entering the cavities (105, 106) adds mass to the AUV (100) and thus enhances the dynamic stability of the AUV (100) against external perturbations due to high currents and swells. Accordingly, the AUV (100) utilizes added mass for enhancing dynamic stability without increasing the dry weight (weight in air) of the AUV.
During operation, the communication unit (102), the battery unit (103) and the steering unit (104) are directly in contact with the water due to the absence of an additional enclosures, thus convective cooling of the communication unit (102), the battery unit (103) and the steering unit (104) is facilitated. Accordingly, the thermal performance of the AUV (100) is improved and thus enables the use of non-metallic materials like composite materials without compromising the cooling ability and thermal management of the AUV (100).
As seen in figure 11, the first cavity (105) is positioned in a front half and the second cavity (106) is positioned in a rear half of the AUV (100). Such distributed positioning of the cavities (105, 106) in the front and rear halves of the AUV (100) provides more stability to the AUV (100) in pitch direction (Y) during operation. The cavities (105, 106) enhance dynamic stability of the AUV (100) by adjusting a mass moment of inertia of the AUV (100) in the pitch (Y) and yaw (Z) axes. In present scenario, the mass moment of inertia of the AUV (100) is directly proportional to the product of mass of water in the first cavity (105) and square of a distance of the first cavity (105) from a rotational axis (Y or Z) of the AUV (100). Similarly, the mass moment of inertia of the AUV (100) is directly proportional to the product of mass of water in the second cavity (106) and square of a distance of the second cavity (106) from the rotational axis (Y or Z) of the AUV (100). The relations for moment of inertia (I) of the AUV (100) are as below:
I1 ∝ M1× (R1)2 -------------(i)
I2 ∝ M2 × (R2)2 -------------(ii)
I ∝ [M1 × (R1)2] + [M2 × (R2)2] -------------(iii)
where I1 is moment of inertia of the AUV (100) for the first cavity (105), I2 is moment of inertia of the AUV (100) for the second cavity (105), M1 is the mass of water in the first cavity (105), M2 is the mass of water in the second cavity (106), R1 is a distance of the first cavity (105) from the rotational axis (Y or Z), R2 is a distance of the second cavity (106) from the rotational axis (Y or Z) and I is moment of inertia of the AUV (100) for both cavities (105, 106).
Since, the cavities (105, 106) are distributed and positioned away from the rotational axis (Y or Z), the mass moment of inertia of the AUV (100) increases. Thus, a AUV (100) with increased mass moment of inertia will have higher resistance to rotational disturbances. Also, the water entering the cavities (105, 106) increases the mass moment of inertia of the AUV (100). Thus, the mass of inertia of the AUV (100) increases without increasing the dry weight of the AUV (100). This enhances the stability of the AUV (100) during operations without affecting its handling characteristics in air.
Further, since the sealed cavities (105, 106) are in contact with the battery unit (103) and the water present in the cavities (105, 106) facilitate convective cooling of the battery unit (103) during operation.
In an embodiment, a pair of heave thruster (108) and a pair of surge thruster (109) are mounted on the frame (101). The heave thrusters (108) are vertically positioned on the frame (101) and each heave thruster (108) is configured to pass through at least one of the first cavity (105) and the second cavity (106). The surge thrusters (109) are mounted laterally on the frame (101) in juxtaposition to the battery unit (103). In an embodiment, at least one sway thruster is horizontally positioned on the frame (101). In an embodiment, each sway thruster is configured to pass through at least one of the first cavity (105) and the second cavity (106). The thrusters (108, 109) facilitate the AUV (100) to move and manoeuvre in many degrees of freedom. Since, the thrusters (108, 109) are positioned in closeness or adjacent to the battery unit (103), the water flow through the thrusters (108, 109) facilitate convective cooling of the battery unit (103). This is very beneficial as the battery unit (103) generates and emits highest amount of heat in the AUV (100).
In an embodiment, the enclosure (107) seals the communication unit (102), the battery unit (103), the steering unit (104), the first cavity (105) and the second cavity (106), such that the said units (102, 103, 104) and cavities (105, 106) are individually and separately sealed. During operation, the enclosure (107) is in contact with the water during operation, the enclosure (107) facilitates convective cooling of the communication unit (102), the battery unit (103) and the steering unit (104).
In an embodiment, each of the air vents and the flood ports have a two-way flow-controlled valve, the flow-controlled valves are actuated by a controller. The controller processes feedback received from at least one sensor and then actuates at least one of the flow-controlled valves of the air vents and the flood ports. In an embodiment, the sensors include and not limited to at least one water level sensor configured in each cavity (105, 106), at least one air pressure sensor configured in each cavity (105, 106), at least one water pressure sensor configured in each cavity (105, 106), at least one gyro sensor configured on the frame (101), at least one accelerometer configured in the frame (101), at least one depth sensor configured on the enclosure (107) and at least one water pressure sensor configured on the enclosure. As the AUV ascends or descends to a certain depth in the water body, the controller actuates the flow-controlled valves based feedback received from the sensors, to control the amount of water entering the cavities (105, 106) thereby controlling the mass of water in the cavities (105, 106).
In an embodiment, each of the cavities (105, 106) are in fluidic connection with an air compressor or a compressed air cylinder. Based on the feedback received from at least one sensor, the controller allows the compressed air from the air compressor or the compressed air cylinder to enter the cavities (105, 106) to expel the water from the cavities (105, 106) through the flood ports. Accordingly, the mass of the water in the cavities (105, 106) can be decreased to maintain the dynamic stability. When the compressed air enters the cavities (105, 106), the flow-controlled valves of the air vent are kept closed. In an embodiment, depending on the pressure difference of air and water in the cavities (105, 106), the opening and closing state of the flow-controlled valves of the flood ports and the air vents are controlled by controller. In an embodiment, depending on the pressure difference of water in the cavities (105, 106) and the water outside the AUV (100), the opening and closing state of the flow-controlled valves of the flood ports and the air vents are controlled by controller. Accordingly, the controller increases and decreases the mass of water in the cavities (105, 106) for enhancing the dynamic stability of the AUV (100).
The foregoing description of specific embodiments of the present invention has been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching.
The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, to thereby enable others, skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated.
It is understood that various omission and substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but such are intended to cover the application or implementation without departing from the spirit or scope of the present invention.
, Claims:
1. An autonomous underwater vehicle (AUV) (100) comprising:
a frame (101);
a communication unit (102) configured on a front end of the frame (101);
a battery unit (103) centrally configured on the frame (101);
a steering unit (104) configured on a rear end of the frame (101);
a first cavity (105) formed between the communication unit (102) and the battery unit (103);
a second cavity (106) formed between the battery unit (103) and the steering unit (104);
an enclosure (107) to seal the first cavity (105) and the second cavity (106);
at least a flood port configured in a first side of the enclosure (107), each flood port is in connection with at least one of the first cavity (105) and the second cavity (106);
at least an air vent configured in a second side of the enclosure (107), the second side is configured opposite to the first side and each air vent is in fluidic connection with at least one of the first cavity (105) and the second cavity (106);
wherein when water enter the cavities (105, 106) through the flood ports, the air vents release air inside the cavities (105, 106) adding mass to the AUV (100) thereby enhancing the dynamic stability of the AUV (100) against external perturbations.

2. The AUV (100) as claimed in claim 1, wherein the frame (101) further comprises a pair of heave thruster (108) and a pair of surge thruster (109), the heave thrusters (108) are vertically positioned on the frame (101) and each heave thruster (108) is configured to pass through at least one of the first cavity (105) and the second cavity (106), the surge thrusters (109) are mounted laterally on the frame (101) in juxtaposition to the battery unit (103), wherein the thrusters (108, 109) configured to facilitate water flow for convective cooling of the battery unit (103).
3. The AUV (100) as claimed in claim 1, wherein the cavities (105, 106) enhance dynamic stability of the AUV (100) by adjusting mass moment of inertia of the AUV (100).

4. The AUV (100) as claimed in claim 3, wherein the mass moment of inertia of the AUV (100) is directly proportional to the product of mass of water in the first cavity (105) and square of a distance of the first cavity (105) from a rotational axis (Y or Z) of the AUV (100).

5. The AUV (100) as claimed in claim 3, wherein the mass moment of inertia of the AUV (100) is directly proportional to the product of mass of water in the second cavity (106) and square of a distance of the second cavity (106) from a rotational axis (Y or Z) of the AUV (100).

6. The AUV (100) as claimed in claim 1, wherein the sealed cavities (105, 106) are in contact with the battery unit (103) to facilitate convective cooling of the battery unit (103).

7. The AUV (100) as claimed in claim 1, wherein each of the air vents and the flood ports has a flow-controlled valve, the flow-controlled valves are actuated by a controller.

8. The AUV (100) as claimed in claim 7, wherein the controller processes feedback received from at least one sensor and actuates at least one of the flow-controlled valves for controlling the mass of water in the cavities (105, 106).

9. The AUV (100) as claimed in claim 8, wherein the sensors include and not limited to at least one water level sensor configured in each cavity (105, 106), at least one air pressure sensor configured in each cavity (105, 106), at least one water pressure sensor configured in each cavity (105, 106), at least one gyro sensor configured on the frame (101), at least one accelerometer configured in the frame (101), at least one depth sensor configured on the enclosure (107) and at least one water pressure sensor configured on the enclosure.