Technical Field

The present disclosure relates generally to modular systems, and in particular to magnetic coupled modular systems, modules and methods for assembling modular systems.

Background

Increased construction and operation of structures in underwater environments such as renewable energy sites, e.g., fixed and floating offshore wind turbines, and tidal power systems, and conventional oil and gas well fields, e.g., decommissioning of offshore wellbores, has driven interest in robotic systems. Robotic systems may serve to autonomously carry out underwater tasks, such as monitoring and intervention, while reducing costs through reliable and repeatable task execution. Robotic systems may be rechargeable allowing for long-term deployment, and may provide valuable system and environmental information exchanged at a local dock. Human presence may be reduced through the use of such robotic systems, thereby mitigating risk to operators in otherwise hazardous and harsh sea environments. Such robotic systems may also be useful in other harsh environment such as space.

Robotic systems may be designed to mimic the high efficiency abilities of underwater creatures. Such bio-inspired underwater systems may utilise a central body line to form a travelling wave thereby generating forward and directional thrust for propulsion and manoeuvring. This category of aquatic locomotion is known as body caudal fin (BCF) motion.

Such BCF underwater systems may consist of a bulk body containing all equipment with dedicated flexible appendages. Alternatively, a modular design distributes electronic and mechanical components along an entire length of the system in discretised modules. A modular design provides flexibility to configure/reconfigure the number and types of modules to lengthen and/or adapt the system depending on application specifics. Further, reliability may be increased via replication of module functionality. The capabilities of modular design may be extended by the addition of new modules without requiring modification and/or replacement of the entire system. Modular designs operating in harsh environments, e.g., underwater, require sealed flexibility for BCF motion. Conventional modular robotic systems operating underwater achieve watertight flexibility either by means of a dynamic O-ring seal or flexible cover. These may place high demands on material and tolerances, and have the potential to degrade over time. Further, the adaptability of the modular designs may be negated, e.g., an inability to access a module within a flexible cover.

This background serves only to set a scene to allow a person skilled in the art to better appreciate the following description. Therefore, none of the above discussion should necessarily be taken as an acknowledgement that that discussion is part of the state of the art or is common general knowledge. One or more aspects/embodiments of the disclosure may or may not address one or more of the background issues.

Summary

According to an aspect of the disclosure there is provided a magnetically coupled modular system.

The system may provide a stronger modular system. For example, joints between adjacent modules may be stronger than conventional robotic systems. The system may additionally or alternatively provide a lighter modular system than conventional prior robotic systems.

The system may provide a connection between adjacent modules while avoiding the need for large, bulky, and/or heavy joint structure. The system may provide torque transfer between adjacent modules without mechanical connections. This may reduce weight and size when compared with conventional robotic systems. The system may provide for synchronous motion between adjacent modules to transfer torque from one module to an adjacent module.

The system may provide reliable and/or low maintenance coupling between modules while ensuring water tightness to protect components internal to modules.

The system may provide modularity which offers opportunities for redundancy and cost reduction through a common design of modules of the system. The system may be adapted to propel through an environment via body caudal fin (BCF) motion. As such the system may be adapted to form a travelling wave to mimic BCF motion. BCF motion describes a category of aquatic motion, which utilises a central body line to form a travelling wave to generate forward and/or directional thrust for propulsion and manoeuvring.

Exemplary environments include undersea or outer space. The system may be adapted to perform a range of tasks including well infrastructure inspection and intervention, and other undersea structural maintenance, service and inspection such as offshore wind turbine structural maintenance and inspection.

The system may comprise a plurality of modules.

At least one module may comprise at least one magnetic element.

The plurality of modules may be coupleable together to maintain synchronous motion between the modules.

Synchronous motion between coupled modules allows for the transference of torque from one module to an adjacent module. In particular, an internal shaft of a module may rotate, and, as the module is coupled to an adjacent module, torque from this rotation may be transferred to a shaft of the adjacent module thereby rotating the adjacent shaft. This torque transference allows for the system to propel through an environment via BCF motion. Torque transference will be described in greater detail below.

The motion between the adjacent modules may be synchronous modules such that when one module moves in a first direction, the other, adjacent modules, move at different phases of the same travelling wave through the system.

Each module of adjacent modules of the plurality of modules may comprise a housing having a curved end face and a magnetic element positioned proximate the curved end face. The housing may be generally cuboid in shape with six faces. The housing may be axisymmetric in Z and Y Cartesian coordinate directions. The housing may have a generally non-cylindrical shape. The faces adjacent the end faces may be curved surfaces with a low degree of curvature. A low degree of curvature may assist displacing and accelerating fluid during undulation (travelling wave motion) of the system through the fluid.

The curved end face may form one of the end faces of the housing. The housing may be generally rectangular. The housing may have two opposite curved end faces. The housing may have a cuboid or rectangular prism shape. The housing may have an elliptical prism shape.

The curved end face of a module may be matching, mating or opposite the curved end face of an adjacent module. In other words, one module may have a curved end face which is generally convex, while the adjacent module may have a curved end face which is generally concave in equal and opposite measure such that the two end faces are matching or mating.

The housing may have a contoured profile along an end face or surface.

The magnetic element may be positioned proximate the curved end face, internally or externally. Internally positioning the magnetic element within the housing may protect the magnetic element from the environment external to the housing which may be a harsh environment, e.g., high or low temperatures, high current, high or low pH, debris, etc.

The housing may comprise a rigid casing for the magnetic element. The magnetic element may be adhered to an internal surface of the housing.

A joint may be formed between abutting curved end faces of the housing of the adjacent modules. The joint may maintain synchronous motion between the adjacent modules.

The joint may comprise a pivot or rotary joint. The joint may only allow rotation around a single axis such that the adjacent modules only have a single degree of freedom between them. The single degree of freedom may comprise yaw of a module to allow for forward propulsion of the modular system.

Alternatively the joint may allow for axial rotation in at least two directions such that adjacent modules have at least two degrees of freedom between them. The at least two degrees of freedom may comprise yaw and pitch to allow for forward propulsion and change in altitude or depth of the modular system. The at least two degrees of freedom may additionally or alternatively comprise roll.

The joint may comprise a magnetic joint. A magnetic joint may be a joint formed between adjacent modules via a magnetic field. The magnetic field is generated by the magnetic element proximate the curved end face.

Torque transferred between adjacent module may be based on a force exerted by the magnetic field of the magnetic element.

Accordingly, in an aspect of the disclosure there is provided a magnetically coupled modular system adapted to propel through an environment via body caudal fin, BCF, motion, the system comprising: a plurality of modules coupleable together to maintain synchronous motion between the plurality of modules, each module of adjacent modules of the plurality of modules comprising a housing having a curved end face, and at least one module of the adjacent modules comprising a magnetic element positioned proximate the curved end face of the respective module, and a joint formed between abutting curved end faces of the housings of the adjacent modules.

The modules may be sealed modules such that water or other elements external to the modules cannot ingress into the internal space defined by each of the modules. The modules may be statically sealed.

The magnetic element may be positioned within a limited arc space of the module. The limited arc space may be limited by the dimensions of the module. The arc space may define a range of angular rotation in one axis, or ranges of angular rotation in multiple axes, e.g., a spherical sector. The arc space may accordingly define a circular sector, or spherical sector, e.g., a hemisphere. An arc space of one module may be identical or different to the arc space of an adjacent modules.

Each of the adjacent modules may comprise a magnetic element. Magnetic elements of adjacent modules may have opposite polarities.

The arc spaces of the adjacent modules may be adjacent in a longitudinal axis formed by the adjacent modules. The longitudinal axis may correspond with the longitudinal axis of either one of the adjacent modules.

Magnetic elements of adjacent modules may be longitudinally aligned. Such aligned magnetic elements may form a magnetic couple with one magnetic element having an opposite magnetic polarity to an adjacent magnetic element forming the magnetic couple. The magnetic couple accordingly creates a magnetic field to couple the adjacent modules and to transfer torque between the modules.

The magnetic elements of adjacent modules may be longitudinally aligned when the modules are aligned along the longitudinal axis, i.e., when there is a 0 degree angle between the adjacent modules.

The magnetic field between adjacent modules may be generated by a magnetic couple comprising aligned magnetic elements in the adjacent modules. The magnetic couple couples the adjacent modules together via forces generated as a result of the magnetic field. Additionally the magnetic couples transfer torque between the adjacent modules to impart motion.

Adjacent modules of the plurality of modules may be coupled together by aligned pairs of magnetic elements forming magnetic couples between adjacent modules.

The restoring torque may be dependent on a relative displacement angle between adjacent modules. Each module of the plurality of modules may comprise a plurality of magnetic elements. For example, each module may comprise four (4) magnetic elements. Each magnetic element may comprise a tile shaped or cuboid magnet.

At least one of the plurality of modules may be statically sealed. The modules may be sealed such that water or other elements external to the modules cannot enter the internal space defined by each of the modules.

At least one of the magnetic elements may comprise a permanent magnet. At least one of the magnetic elements may comprise another form of a magnet such as electromagnetic, e.g., solenoid. Further, the magnetic elements may comprise some combination of magnets. For example, one module may comprise at least one permanent magnet while an adjacent module comprises an electromagnet such that a magnetic couple formed between magnetic elements of adjacent modules is formed between a permanent magnet and an electromagnet.

At least one module of the plurality of modules may comprise a magnetic element comprising a Halbach array, a Halbach cylinder or Halbach sphere. Such arrangements may increase the magnetic field generated by the magnetic element thereby increasing the coupling force between adjacent modules while also reducing the overall weight of the modules due to a reduction in the weight of the magnetic element.

The magnetic element may comprise an arc shell sector shape. The housing of a module may have a curved end face having a corresponding arc shell sector shape. An arc shell sector may be defined as arcuate sector of the outer shell or surface of a circle. The magnetic element may have the shape of an arcuate sector of the outer shell or surface of a circle. The curved end face of the housing may have a similar shape.

The magnetic element may have a spherical shell sector shape. The housing of a module may have a curved end face having a corresponding spherical shell sector shape. A spherical shell sector may be defined as a spherical sector of the outer shell or surface of a sphere. The magnetic element may have the shape of a spherical sector of the outer shell or surface of a sphere. The curved end face of the housing may have a similar shape.

The magnetic element may have a spherical cap shape.

Each module of the plurality of modules may comprise at least one magnetic element for maintaining synchronous motion between the plurality of modules.

Each module of the plurality of modules may comprise a plurality of magnetic elements for maintaining synchronous motion between the plurality of modules. For example, each module may comprise four (4) magnetic elements.

The at least one module may comprise a motor for actuating the joint. The motor may comprise a servomechanism, i.e. , servo. The motor may be adapted to transfer rotatory motion to the magnetic element to actuate the joint.

The at least one module may comprise a shaft and the magnetic element may be connected to the shaft.

The motor may be adapted to transfer rotary motion to the shaft to actuate the shaft. A belt or other synchronization mechanism may be used to transfer motion from the motor to the shaft. Rotation of the shaft and magnetic element mounted thereto may transfer a torque to the adjacent module via the magnetic field attraction between the adjacent modules.

The at least one module may comprise a motor for actuating the joint. The motor may comprise a servomechanism, i.e., servo. The motor may be adapted to transfer rotatory motion to the magnetic element to actuate the joint. The motor may comprise a shaft (armature) and one or more additional magnetic elements (stator). The shaft rotates within a volume defined by the additional magnetic elements (stator). The previously described magnetic elements may be incorporated with elements of the motor. In particular, the additional magnetic elements (stator) of the motor may comprise the magnetic elements of a module. This arrangement may reduce the overall size of the motor and magnetic elements as the additional magnetic elements (stator) of the motor are eliminated in place of the magnetic elements of the module. Further, no synchronisation mechanism, e.g., belt, gear assembly, is required to transfer rotation from the shaft of the motor to a shaft on which the magnetic element is positioned as the magnetic element and the motor share the same shaft. This may reduce the size and weight of the module. Further, this may allow for additional space for other components within the module such as sensors, communication modules, processors, memory, power sources, etc.

The magnetic field between the adjacent modules may impart a restoring torque during rotation of the shaft such that the adjacent module moves in the same direction as the rotating shaft. Such movement may impart BCF motion on the system.

The motion of the adjacent module may be transferred to a further module via the same combination of synchronisation mechanism, e.g., belt, gear assembly, and shaft on which a magnetic element is positioned. In particular, the adjacent module may comprise a first magnetic element positioned proximate one curved end face of the module, and a second magnetic element positioned proximate the opposite curved end of the module. The second magnetic element may be connected to another shaft onto which rotary motion is transferred.

The modular system may further comprise a decoupling mechanism for decoupling a module from an adjacent module. The decoupling mechanism may be an actuated decoupling mechanism controlled by a controller present in the system, or remotely located. The controller may control the decoupling mechanism to decouple adjacent modules based on sensed parameters such as force, resistance, fatigue, stress, strain, etc. The decoupling mechanism may comprise a demagnetising mechanism such as a demagnetising coil adapted to demagnetise one or more magnetic elements. The controller may control the demagnetising coil to demagnetise a magnetic element and decouple adjacent modules.

The decoupling mechanism may comprise a rotation means such as a motor, servomechanism, rotary arm, etc., for rotating magnetic elements of adjacent modules out of magnetic element, i.e., such that magnetic elements do not exert an attractive force, and/or exert a repelling force. The decoupling mechanism may comprise a switch or other electrical element which prevent a magnetic element generating a magnetic field. For example, if the magnetic element comprises an electromagnet, the decoupling mechanism may comprise a switch for preventing electrical power to the electromagnet and de-energising or preventing energising of the electromagnet.

Adjacent modules may decouple due to excessive force. For example, if one of the modules is put under stress or strain in an operating environment, the applied force may overcome the magnetic force attracting adjacent magnetic elements of adjacent modules. The applied force may accordingly force decoupling of the modules. This may advantageously protect the modular system from damage with only a single module requiring replacement.

At least one module may include a ball bearing on an outer surface thereof. The ball bearing may align adjacent modules. The ball bearing may allow for smoother and/or more controller motion between the modules. The ball bearing may be positioned within a recess of a curved surface. The ball bearing may form a spherical rolling joint.

At least one module may include a plurality of ball bearings on an outer surface thereof. The ball bearings may align adjacent modules. The ball bearings may allow for smoother and/or more controller motion between the modules. The ball bearings may each be positioned within a recess of a curved surface. The ball bearings may form a spherical rolling joint.

According to another aspect of the disclosure there is provided a magnetically coupled modular system adapted to propel through an environment via body caudal fin, BCF, motion, the system comprising: a driving module comprising a housing having a curved end face and at least one magnetic element positioned proximate the curved end face, and a driven module comprising a housing having a curved end face mirroring the curved end face of the driving module and arranged to abut the curved end face of the driving module, the magnetic element generating a magnetic field to maintain synchronous motion between the modules. According to another aspect of the disclosure there is provided a magnetically coupled modular system adapted to propel through an environment via body caudal fin, BCF, motion, the system comprising: a plurality of modules, at least one module comprising at least one magnetic element and adjacent modules of the plurality of modules coupled together by a magnetic field generated by the magnetic element, wherein at least one magnetic element of each of the adjacent modules is positioned within a limited arc space of the corresponding module, and the arc spaces of the adjacent modules are adjacent in a longitudinal axis formed by the adjacent modules.

The systems may include any and all of the features, elements and/or benefits described in respect of the previously-described magnetically coupled modular system.

At least one module of the plurality of modules of any of the described systems may comprise an end effector. A single module of the plurality of modules may comprise an end effector. The module may correspond to one of the modules at either end of the plurality of modules. In other words, one of the modules which is only coupled to a single adjacent module of the plurality of modules may comprise an end effector.

The end effector may comprise a gripper or welding tool, or any number of possible tools, implements or devices. The gripper may comprise a mechanical gripper, a pneumatic gripper, a magnetic gripper or suction cup. The welding tool may comprise a welding torch. The end effector may allow the modular system to interact with the environment. The end effector may allow the modular system to perform particular tasks.

At least one module of the plurality of modules may be connected to a base, A single module of the plurality of modules may be connected to a base. The module may correspond to one of the modules at either end of the plurality of modules. In other words, one of the modules which is only coupled to a single adjacent module of the plurality of modules may be connected to the base. The module connected to the base may be opposite to a module which comprises an end effector. These two modules may be at opposite ends of the plurality of coupled modules when formed into the modular system.

The base may comprise an offshore structure such as a wind turbine or an offshore oil and gas platform. The base may comprise a free swimming robot. The base may comprise a ROV. The base may be fixed.

The modular system may be used in a variety of applications including applications in an oil and gas field, e.g., oil and gas platform. The modular system may allow for all internal components to be contained within the plurality of modules which may be watertight. This may include electronics components. Housing internal components within watertight modules may allow for easier (i.e., faster and cheaper) certification of the modular system for use in various applications including renewable, and oil and gas applications offshore.

The at least one module of the adjacent modules may comprise a plurality of magnetic elements, e.g., magnetic element segments, positioned proximate the curved end face of the respective module. Similarly, a module adjacent to the at least one module may comprise a plurality of magnetic elements positioned proximate the curved end face of the adjacent module. Each of the plurality of magnetic elements may have a generally arcuate shape.

The plurality of magnetic elements may comprise at least one magnetic element adapted to generate a magnetic field which may be altered. The plurality of magnetic elements or segments may comprise one or more permanent magnets and at least one electromagnet. The magnetic field generated by the electromagnet may be varied. That is to say, the electromagnet may be adapted to vary the magnetic field it generates. At least one magnetic element, e.g., magnetic element segment, may comprise a coil for generating a magnetic field. By controlling a current (intensity and direction) through the coil, the field generated by the coil may be varied. The field may be generated to encode a data or power signal. The data or power signal may be received by a magnetic element of an adjacent module. The magnetic element of the adjacent module may comprise a coil. The system may further comprise a controller. The controller may be for effecting wireless data or power transfer between modules, including adjacent modules. The controller may be for using electromagnetic fields to transmit data wirelessly between modules, including adjacent modules. The controller may control a magnetic field generated by at least one magnetic element of the plurality of magnetic elements. The controller may be external, i.e., remote, to the modular system or may be contained within a particular module. The controller may be adapted to control a magnetic field generated by one or more of the magnetic elements. The controller may be adapted for controlling or varying a magnetic field to transfer a data or power signal from one module to another adjacent module. The controller may be adapted for controlling or varying a magnetic field generated by a magnetic element of a module to transfer a data or power signal between modules. The controller may be for controlling a magnetic field generated by at least one magnetic element of the plurality of magnetic elements to transfer a data or power signal from the at least one module of the adjacent modules to a respective adjacent module. The controller may control the direction and/or intensity of a current flowing through a magnetic element, e.g., coil, to modulate a data or power signal for communication between adjacent modules via electromagnetic induction.

At least one of the magnetic elements may be adapted to vary an associated generated magnetic field to transmit or transfer a data or power signal between modules. At least one of the magnetic elements of an adjacent module may be adapted to vary an associated generated magnetic field to receive a transmitted data or power signal.

The data signal may comprise telemetry data associated with the modular system. The data signal may comprise sensor data collected via one or more sensors associated with the modular system. The power signal may be electrical power transferred from one module to an adjacent module. This may ensure that one module which is otherwise low on power may continue to operate with electrical power transferred from an adjacent module.

According to another aspect there is provided a module for use in a magnetically coupled modular system adapted to propel through an environment via body caudal fin, BCF, motion, the magnetically coupled modular system comprising a plurality of modules, the module comprising: a housing having a curved end face and a magnetic element positioned proximate the curved end face of the housing, the module adapted to form a joint with an adjacent module of the modular system between the curved end face and a corresponding curved end face of a housing of the adjacent module.

The curved end face may be generally arcuate or spherical shaped.

The magnetic element may have a generally arcuate or spherical shape corresponding to the curved end face of the housing.

The housing may have a cuboid shape. The housing may have an elliptical prism shape.

The module may have two curved end faces.

The magnetic element may comprise a Halbach array, Halbach cylinder or Halbach sphere.

The module may comprise a plurality of magnetic elements positioned proximate the curved end face. Adjacent magnetic elements of the plurality of magnetic elements may have opposite polarity.

The module may further comprise a decoupling mechanism for decoupling the module from an adjacent module. The decoupling mechanism may be an actuated decoupling mechanism controlled by a controller present in the module, or remotely located. The controller may control the decoupling mechanism to decouple adjacent modules based on sensed parameters such as force, resistance, fatigue, stress, strain, etc. The decoupling mechanism may comprise a demagnetising mechanism such as a demagnetising coil adapted to demagnetise one or more magnetic elements. The controller may control the demagnetising coil to demagnetise a magnetic element and decouple adjacent modules. The module may comprise an end effector. The end effector may comprise a gripper or welding tool, or any number of possible tools, implements or devices. The gripper may comprise a mechanical gripper, a pneumatic gripper, a magnetic gripper or suction cup. The welding tool may comprise a welding torch. The end effector may allow the module to interact with the environment. The end effector may allow the module to perform particular tasks.

The module may be connected to a base. The base may comprise an offshore structure such as a wind turbine or oil and gas platform. The base may comprise a free swimming robot. The base may comprise a ROV. The base may be fixed.

The module may be watertight. The module may house internal electronics. Housing internal components within a watertight module may allow for easier (i.e., faster and cheaper) certification of the module for use in various applications including renewable, and oil and gas applications offshore.

The module may comprise a plurality of magnetic elements, e.g., magnetic element segments, positioned proximate the curved end face of the module. The plurality of magnetic elements may comprise at least one magnetic element, e.g., magnetic element segment, adapted to generate a magnetic field which may be altered. The plurality of magnetic elements may comprise one or more permanent magnets and at least one electromagnet. Each of the plurality of magnetic elements may have a generally arcuate shape. The magnetic element may comprise a coil. The magnetic field generated by the electromagnet or coil may be varied. That is to say, the electromagnet or coil may be adapted to vary the magnetic field it generates. By controlling a current (intensity and direction) through the coil, the field generated by the coil may be varied. The field may be generated to encode a data or power signal. The data or power signal may be received by a magnetic element of an adjacent module. The magnetic element of the adjacent module may comprise a coil.

A controller may be present for effecting wireless data transfer between modules, including adjacent modules. The controller may be present for using electromagnetic fields to transmit data wirelessly between modules, including adjacent modules. The controller may control a magnetic field generated by at least one magnetic element of the plurality of magnetic elements. The controller may be external, i.e., remote, to the module or may be contained within the module. The controller may be adapted to control a magnetic field generated by one or more of the magnetic elements. The controller may be adapted for controlling or varying a magnetic field to transfer a data or power signal from the module to another adjacent module. The controller may be adapted for controlling or varying a magnetic field generated by a magnetic element of the module to transfer a data or power signal between modules. The controller may be for controlling a magnetic field generated by at least one magnetic element of the plurality of magnetic elements to transfer a data or power signal from the module of adjacent modules to the module. The controller may control the direction and/or intensity of a current flowing through a magnetic element, e.g., coil, to modulate a data or power signal for communication between adjacent modules via electromagnetic induction.

At least one of the magnetic elements may be adapted to vary an associated generated magnetic field to transmit, transfer or receive a data or power signal between modules. At least one of the magnetic elements of an adjacent module may be adapted to vary an associated generated magnetic field to receive a transmitted data or power signal.

The data signal may comprise telemetry data associated with the module. The data signal may comprise sensor data collected via one or more sensors associated with the module. The power signal may transfer electrical power from one module to an adjacent module. This may ensure that one module which is otherwise low on power may continue to operate with electrical power transferred from an adjacent module.

The module may comprise other features and elements described in respect of the modular system, e.g., motor, belt, etc. Additionally, the module may provide any of the benefits described in relation to the modular systems.

According to another aspect there is provided a method of assembling a magnetically coupled modular system adapted to propel through an environment via body caudal fin, BCF, motion, the method comprising: forming a joint between a module comprising a housing having a curved end surface and a magnetic element positioned proximate the curved end surface and an adjacent module to magnetically couple the modules. The adjacent module may comprise a housing having a curved end surface mirroring the curved end surface of the module.

Forming may comprise abutting the curved end surfaces of the modules.

The method may further comprise decoupling adjacent modules. Decoupling may comprise applying a threshold level of force to overcome magnetic attraction between adjacent modules.

Decoupling may comprise actuating a decoupling mechanism to decouple adjacent modules. The decoupling mechanism may comprise a demagnetising coil for demagnetising a magnetic element of a module.

The method may further comprise controlling actuating of the decoupling mechanism to decouple adjacent modules. Controlling may comprise remotely controlling actuating of the decoupling mechanism via a controller remote to the system. The controller may be located remote to the operating environment of the system. Alternatively, the controller may be present in one or more of the plurality of housings.

Such decoupling may protect the system from damage with only a single decoupled module requiring replacement or reconnection. Additionally, controlled decoupling may allow for replacement of faulty or damaged modules, or coupling of modules adapted to perform a particular task, such as modules having specific sensors for servicing or maintenance of undersea structures.

The method may further comprise forming one or more additional joints between a plurality of modules and an additional module comprising a housing having a curved end surface and a magnetic element positioned proximate the curved end surface of an end module of the plurality of modules to magnetically couple the additional module and the end module.

The method may further comprise communicating a data or power signal between modules via at least one of a plurality of magnetic elements, e.g., magnetic element segments, which includes the magnetic element. The method may further comprise communicating the data or power signal between adjacent modules. Communicating the data or power signal may comprise varying a magnetic field generated by the at least one magnetic element, e.g., one magnetic element segment. The magnetic element may comprise an electromagnet. Varying may comprise controlling the operation of the electromagnet. Operation of the electromagnet may be controlled via a controller. The controller may be remote to the modular system. The controller may be within one of the modules of the modular system. Communicating the data or power signal may comprise varying a current through the at least one magnetic element of a module to induce a charge in a magnetic element of an adjacent module. Data or power may be induced in the magnetic element of the adjacent module via induction.

The data signal may comprise telemetry data associated with the modular system. The data signal may comprise sensor data collected via one or more sensors associated with the modular system. The power signal may transfer electrical power from one module to an adjacent module. This may ensure that one module which is otherwise low on power may continue to operate with electrical power transferred from an adjacent module.

The described modular system and/or modules may be formed using an additive manufacturing process. Alternatively, the described modular system and/or modules may be formed by conventional manufacturing methods including, CNC cutting, milling and subtractive manufacturing. A common example of additive manufacturing is 3D printing; however, other methods of additive manufacturing are available. Rapid prototyping or rapid manufacturing are also terms which may be used to describe additive manufacturing processes.

As used herein, “additive manufacturing” refers generally to manufacturing processes wherein successive layers of material(s) are provided on each other to “build-up” layer- by-layer or “additively fabricate” a three-dimensional component. This is compared to some subtractive manufacturing methods (such as milling or drilling), wherein material is successively removed to fabricate the part. The successive layers generally fuse together to form a monolithic component which may have a variety of integral subcomponents. In particular, the manufacturing process may allow an example of the disclosure to be integrally formed and include a variety of features not possible when using prior manufacturing methods. Additive manufacturing methods described herein enable manufacture to any suitable size and shape with various features which may not have been possible using prior manufacturing methods. Additive manufacturing can create complex geometries without the use of any sort of tools, moulds or fixtures, and with little or no waste material. Instead of machining components from solid billets of plastic or metal, much of which is cut away and discarded, the only material used in additive manufacturing is what is required to shape the part.

Suitable additive manufacturing techniques in accordance with the present disclosure include, for example, Fused Deposition Modeling (FDM), Selective Laser Sintering (SLS), 3D printing such as by inkjets and laserjets, Sterolithography (SLA), Direct Selective Laser Sintering (DSLS), Electron Beam Sintering (EBS), Electron Beam Melting (EBM), Laser Engineered Net Shaping (LENS), Electron Beam Additive Manufacturing (EBAM), Laser Net Shape Manufacturing (LNSM), Direct Metal Deposition (DMD), Digital Light Processing (DLP), Continuous Digital Light Processing (CDLP), Direct Selective Laser Melting (DSLM), Selective Laser Melting (SLM), Direct Metal Laser Melting (DMLM), Direct Metal Laser Sintering (DMLS), Material Jetting (MJ), NanoParticle Jetting (NPJ), Drop On Demand (DOD), Binder Jetting (BJ), Multi Jet Fusion (MJF), Laminated Object Manufacturing (LOM) and other known processes such as extrusion.

The additive manufacturing processes described herein may be used for forming components using any suitable material. For example, the material may be plastic, metal, composite, concrete, ceramic, polymer, epoxy, photopolymer resin, or any other suitable material that may be in solid, liquid, powder, sheet material, wire, or any other suitable form or combinations thereof. More specifically, according to exemplary embodiments of the present subject matter, the additively manufactured components described herein may be formed in part, in whole, or in some combination of materials including but not limited to pure metals, nickel alloys, chrome alloys, titanium, titanium alloys, magnesium, magnesium alloys, aluminium, aluminium alloys, iron, iron alloys, stainless steel, and nickel or cobalt based superalloys (e.g., those available under the name Inconel® available from Special Metals Corporation). These materials are examples of materials suitable for use in additive manufacturing processes which may be suitable for the fabrication of examples described herein. As noted above, the additive manufacturing process disclosed herein allows a single component to be formed from multiple materials. Thus, the examples described herein may be formed from any suitable mixtures of the above materials. For example, a component may include multiple layers, segments, or parts that are formed using different materials, processes, and/or on different additive manufacturing machines. In this manner, components may be constructed which have different materials and material properties for meeting the demands of any particular application. In addition, although the components described herein are constructed entirely by additive manufacturing processes, it should be appreciated that in alternate embodiments, all or a portion of these components may be formed via casting, machining, and/or any other suitable manufacturing process. Indeed, any suitable combination of materials and manufacturing methods may be used to form these components.

Additive manufacturing processes typically fabricate components based on three- dimensional (3D) information, for example a three-dimensional computer model (or design file), of the component.

Accordingly, examples described herein not only include products (or components) as described herein, but also methods of manufacturing such products via additive manufacturing and computer software, firmware or hardware for controlling the manufacture of such products via additive manufacturing.

The structure of one or more parts of the modular system and/or module may be represented digitally in the form of a design file. A design file, or computer aided design (CAD) file, is a configuration file that encodes one or more of the surface or volumetric configuration of the shape of the product. That is, a design file represents the geometrical arrangement or shape of the modular system and/or module.

Design files can take any now known or later developed file format. For example, design files may be in the Stereolithography or “Standard Tessellation Language” (.stl) format which was created for stereolithography CAD programmes of 3D Systems, or the Additive Manufacturing File (.amf) format, which is an American Society of Mechanical Engineers (ASME) standard that is an extensible markup-language (XML) based format designed to allow any CAD software to describe the shape and composition of any three-dimensional object to be fabricated on any additive manufacturing printer.

Further examples of design file formats include AutoCAD (.dwg) files, Blender (.blend) files, Parasolid (,x_t) files, 3D Manufacturing Format (,3mf) files, Autodesk (3ds) files, Collada (.dae) files and Wavefront (.obj) files, although many other file formats exist.

Design files can be produced using modelling (e.g. CAD modelling) software and/or through scanning the surface of a system and/or module to measure the surface configuration of the modular system and/or module.

Once obtained, a design file may be converted into a set of computer executable instructions that, once executed by a processer, cause the processor to control an additive manufacturing apparatus to produce the modular system and/or module according to the geometrical arrangement specified in the design file. The conversion may convert the design file into slices or layers that are to be formed sequentially by the additive manufacturing apparatus. The instructions (otherwise known as geometric code or “G-code”) may be calibrated to the specific additive manufacturing apparatus and may specify the precise location and amount of material that is to be formed at each stage in the manufacturing process. As discussed above, the formation may be through deposition, through sintering, or through any other form of additive manufacturing method.

The code or instructions may be translated between different formats, converted into a set of data signals and transmitted, received as a set of data signals and converted to code, stored, etc., as necessary. The instructions may be an input to the additive manufacturing system and may come from a part designer, an intellectual property (IP) provider, a design company, the operator or owner of the additive manufacturing system, or from other sources. An additive manufacturing system may execute the instructions to fabricate the system and/or module using any of the technologies or methods disclosed herein.

Design files or computer executable instructions may be stored in a (transitory or non- transitory) computer readable storage medium (e.g., memory, storage system, etc.) storing code, or computer readable instructions, representative of the product to be produced. As noted, the code or computer readable instructions defining the modular system and/or module that can be used to physically generate the object, upon execution of the code or instructions by an additive manufacturing system. For example, the instructions may include a precisely defined 3D model of the product and can be generated from any of a large variety of well-known computer aided design (CAD) software systems such as AutoCAD®, TurboCAD®, DesignCAD 3D Max, etc. Alternatively, a model or prototype of the component may be scanned to determine the three-dimensional information of the component.

Accordingly, by controlling an additive manufacturing apparatus according to the computer executable instructions, the additive manufacturing apparatus can be instructed to print/fabricate one or more parts of the modular system and/or module. These can be printed either in assembled or unassembled form. For instance, different sections of the product may be printed separately (as a kit of unassembled parts) and then subsequently assembled. Alternatively, the different parts may be printed in assembled form.

In light of the above, embodiments include methods of manufacture via additive manufacturing. This includes the steps of obtaining a design file representing the modular system and/or module and instructing an additive manufacturing apparatus to manufacture the modular system and/or module in assembled or unassembled form according to the design file. The additive manufacturing apparatus may include a processor that is configured to automatically convert the design file into computer executable instructions for controlling the manufacture of the modular system and/or module. In these embodiments, the design file itself can automatically cause the production of the modular system and/or module once input into the additive manufacturing device. Accordingly, in this embodiment, the design file itself may be considered computer executable instructions that cause the additive manufacturing apparatus to manufacture the modular system and/or module. Alternatively, the design file may be converted into instructions by an external computing system, with the resulting computer executable instructions being provided to the additive manufacturing device.

Given the above, the design and manufacture of implementations of the subject matter and the operations described in this specification can be realized using digital electronic circuitry, or in computer software, firmware, or hardware, including the structures disclosed in this specification and their structural equivalents, or in combinations of one or more of them. For instance, hardware may include processors, microprocessors, electronic circuitry, electronic components, integrated circuits, etc. Implementations of the subject matter described in this specification can be realized using one or more computer programs, i.e. , one or more modules of computer program instructions, encoded on computer storage medium for execution by, or to control the operation of, data processing apparatus. Alternatively or in addition, the program instructions can be encoded on an artificially generated propagated signal, e.g., a machine-generated electrical, optical, or electromagnetic signal that is generated to encode information for transmission to suitable receiver apparatus for execution by a data processing apparatus. A computer storage medium can be, or be included in, a computer-readable storage device, a computer-readable storage substrate, a random or serial access memory array or device, or a combination of one or more of them. Moreover, while a computer storage medium is not a propagated signal, a computer storage medium can be a source or destination of computer program instructions encoded in an artificially generated propagated signal. The computer storage medium can also be, or be included in, one or more separate physical components or media (e.g., multiple CDs, discs, or other storage devices).

Although additive manufacturing technology is described herein as enabling fabrication of complex objects by building objects point-by-point, layer-by-layer, typically in a vertical direction, other methods of fabrication are possible and within the scope of the present subject matter. For example, although the discussion herein refers to the addition of material to form successive layers, one skilled in the art will appreciate that the methods and structures disclosed herein may be practiced with any additive manufacturing technique or other manufacturing technology.

According to another aspect there is provided a computer program comprising computer executable instructions that, when executed by a processor, cause the processor to control an additive manufacturing apparatus to manufacture the described modular system and/or module.

According to another aspect there is provided a non-transitory computer readable medium having computer program code stored thereon, the code executable by a processor to control an additive manufacturing apparatus to manufacture the described modular system and/or module.

According to another aspect there is provided a method of manufacturing a device via additive manufacturing, the method comprising: obtaining an electronic file representing a geometry of a product wherein the product is the described modular system and/or module; and controlling an additive manufacturing apparatus to manufacture, over one or more additive manufacturing steps, the product according to the geometry specified in the electronic file.

The above summary is intended to be merely exemplary and non-limiting.

Brief Description of the Drawings

These and other aspects of the present disclosure will now be described, by way of example only, with reference to the accompanying Figures, in which:

Figure 1 is a block diagram of a modular robotic system;

Figure 2 is a cutaway front section view of a modular robotic system;

Figure 3 is a plan view of a magnetically coupled modular system with highlighted features;

Figure 4a is a side elevation view of a portion of the system of Figure 3;

Figure 4b is an enlarged plan view of a portion of the system of Figure 3;

Figure 5 is an isometric partial exploded view of the portion of the system of Figure 4;

Figure 6 is an exploded view of the portion of the system of Figure 4;

Figure 7 is an electrical schematic diagram of components of an electronic housing of the system of Figure 3;

Figure 8 is a diagram of adjoining modules of the system of Figure 3;

Figures 9a and 9b are force diagrams of adjacent magnetic elements of the system of Figure 3;

Figure 10a is a graph of force curves of a prototype magnetically coupled modular system;

Figure 10b is a graph of torque relative to load angle of a prototype magnetically coupled modular system; Figure 11 is a graph of magnetic field intensity of magnetic elements of a prototype magnetically coupled modular system;

Figures 12a and 12b are graphs of amplitude envelope of a prototype magnetically coupled modular system during testing;

Figure 13 is a graph of module trajectory of a prototype magnetically coupled modular system during testing;

Figures 14a, 14c and 14e are graphs of roll, pitch and yaw for 3.5 circles of a prototype magnetically coupled modular system during testing;

Figures 14b, 14d and 14f are graphs of roll, pitch and yaw for one full circle of a prototype magnetically coupled modular system during testing;

Figure 15a is a graph of thrust of a prototype magnetically coupled modular system;

Figure 15b is a graph of instantaneous thrust of a prototype magnetically coupled modular system;

Figure 16a is another graph of thrust of a prototype magnetically coupled modular system;

Figure 16b is another graph of instantaneous thrust of a prototype magnetically coupled modular system;

Figures 17a-17d are graphs of thrust curves of prototype magnetically coupled modular systems;

Figure 18 is a graph of thrusts of prototype magnetically coupled modular systems;

Figure 19 is a plan view of another magnetically coupled modular system with highlighted features;

Figure 20 is a front elevation view of the system of Figure 19;

Figures 21a-c are cut-away views of a portion of the system of Figure 19;

Figure 22 is a plan view of another magnetically coupled modular system with highlighted features;

Figures 23a-b are views of another magnetically coupled modular system with highlighted features; and

Figures 24a-b are a sequence of steps for decoupling adjacent modules of a magnetically coupled modular system.

Detailed Description of the Drawings

The foregoing summary, as well as the following detailed description of certain embodiments will be better understood when read in conjunction with the accompanying drawings. As will be appreciated, like reference characters are used to refer to like elements throughout the description and drawings. As used herein, an element or feature recited in the singular and preceded by the word "a" or "an" should be understood as not necessarily excluding a plural of the elements or features. Further, references to "one example" or “one embodiment” are not intended to be interpreted as excluding the existence of additional examples or embodiments that also incorporate the recited elements or features of that one example or one embodiment. Moreover, unless explicitly stated to the contrary, examples or embodiments "comprising", "having" or “including” an element or feature or a plurality of elements or features having a particular property might further include additional elements or features not having that particular property. Also, it will be appreciated that the terms “comprises”, “has” and “includes” mean “including but not limited to” and the terms “comprising”, “having” and “including” have equivalent meanings.

As used herein, the term “and/or” can include any and all combinations of one or more of the associated listed elements or features.

It will be understood that when an element or feature is referred to as being “on”, “attached” to, “connected” to, “coupled” with, “contacting”, etc. another element or feature, that element or feature can be directly on, attached to, connected to, coupled with or contacting the other element or feature or intervening elements may also be present. In contrast, when an element or feature is referred to as being, for example, “directly on”, “directly attached” to, “directly connected” to, “directly coupled” with or “directly contacting” another element of a feature, there are no intervening elements or features present.

It will be understood that spatially relative terms, such as “under”, “below”, “lower”, “over”, “above”, “upper”, “front”, “back” and the like, may be used herein for ease of describing the relationship of an element or feature to another element or feature as depicted in the figures. The spatially relative terms can however, encompass different orientations in use or operation in addition to the orientation depicted in the figures.

Reference herein to “example” means that one or more feature, structure, element, component, characteristic and/or operational step described in connection with the example is included in at least one embodiment and or implementation of the subject matter according to the present disclosure. Thus, the phrases “an example,” “another example,” and similar language throughout the present disclosure may, but do not necessarily, refer to the same example. Further, the subject matter characterizing any one example may, but does not necessarily, include the subject matter characterizing any other example.

Reference herein to “configured” denotes an actual state of configuration that fundamentally ties the element or feature to the physical characteristics of the element or feature preceding the phrase “configured to”.

Unless otherwise indicated, the terms “first,” “second,” etc. are used herein merely as labels, and are not intended to impose ordinal, positional, or hierarchical requirements on the items to which these terms refer. Moreover, reference to a “second” item does not require or preclude the existence of a lower-numbered item (e.g., a “first” item) and/or a higher-numbered item (e.g., a “third” item).

As used herein, the terms “approximately” and “about” represent an amount close to the stated amount that still performs the desired function or achieves the desired result. For example, the terms “approximately” and “about” may refer to an amount that is within less than 10% of, within less than 5% of, within less than 1% of, within less than 0.1% of, or within less than 0.01% of the stated amount.

A magnetically coupled modular system adapted to propel through an environment via BCF motion is disclosed. The system comprises a plurality of modules coupled together to maintain synchronous motion between them. The modules are coupled together via magnetic fields generated by magnetic elements present in each module. Each module comprises a housing having at least one curved end face. A magnetic element is positioned within the housing proximate the curved end face. Joints are formed between adjacent modules. In particular, a joint is formed between abutting curved end faces of the housings of adjacent modules via magnetic attraction between magnetic elements in the adjacent housings.

While the term abutting has been used, adjacent modules may be in a non-contact arrangement or may in fact be in direct contact such that curved end faces of adjacent modules physically contact each other. The magnetic element of one module and an aligned magnetic element of the adjacent module form a magnetic couple. Multiple magnetic elements may be present in both the housings of adjacent modules thereby forming multiple magnetic couples between adjacent modules.

As the housing has a curved end face, the magnetic elements are only positioned within a limited arc space of the curved end face of the housing. Accordingly, the joint formed between the magnetic couples does not take up significant space, and is not of significant weight. This allows for the modular system to be lighter and more streamlined.

Additionally, the modular system does not require a mechanical connection between adjacent modules. Such mechanical, yet flexible connections between rigid bodies is problematic as a watertight connection is required between modules. Manufacturing mechanical connection components for water tightness places high demands on manufacturing tolerances. Additionally such mechanical connections, which may include dynamic O-ring seals, have the potential to degrade over time.

An alternative solution is the use of a flexible cover over the entirety of the modular system, or alternatively across the joint area between adjacent modules. However, such a system may be damaged during use by impact with objects in the environment such as undersea rocks. Additionally, the use of a cover of the modular system limits the adaptability of the system. Modules cannot be seamlessly coupled, removed or replaced without first removing the cover. This reduces efficiency and increases operating costs of the system.

The magnetic elements of a module are connected to a shaft within the housing of that module. When the shaft rotates, the magnetic couples between magnetic elements of the adjacent module transfer the torque of the rotating shaft to a shaft on which magnetic elements in the adjacent module are connected. Thus, rotation of a shaft in one module is transferred to a shaft in an adjacent module. In this manner, torque may be transferred along the modular system between modules. The transference of torque propels the modular system through an environment via BCF motion. The magnetic elements in one module are mounted on a rotatable shaft with the magnetic elements of an adjacent module being mounted on a rotatable shaft within the adjacent module.

A motor positioned within the housing is used to rotate a shaft on which the magnetic element within the housing is mounted. Rotary motion is transferred from the motor to the shaft via a timing belt. The magnetic elements may be incorporated with elements of the motor. For example, magnetic elements, i.e., stator, of the motor may comprise the described magnetic elements.

Turning now to Figure 1, a block diagram of a modular system 10 is illustrated. The modular system 10 comprises a plurality of modules 12. The modular system 10 has a single degree of freedom between modules 12. The system 10 comprises n modules 12 with adjacent modules 12 being rotatably connected together. Rotation of the modules 12 provides for motion of the system 10 via BCF motion. As shown in Figure 1 , the rotation axis is perpendicular to a longitudinal axis of the modules which is identified as A in the drawing.

The modular system 10 is illustrated with an outer cover resembling an aquatic creature in Figure 2. As illustrated the modules 12 may form unique body elements of the modular system 10, i.e., a head 14, body 16 and tail fin 18. The head 14 houses sensor systems for navigation and leads the modular system 10. The shape of the head 14 may have significant influence on the drag and steering of the system 10. The head 14 is coupled to the body 16 comprising a series of repeating body segments. The segments have constant aspect ratios.

The tail fin 18 is the final component of the system and is coupled to the body 16. The tail fin 18 may influence vortex shedding at the trailing end. The tail fin 18 may comprise a flexible structure, which passively extends a body wave generated by the modular system 10.

The modules 12 may provide rigid bodies which form the head 14, body 16 and tail fin 18 of the modular system 10. One or more modules 12 forming the head 14 and tail 18 may be unique, while modules 12 forming the body 16 may be identical in their internal components. The modules 12 provide protection for internal mechanical and electronic components, while flexibility is implemented via connecting joints between the modules 12.

Turning now to Figures 3-6, a magnetically coupled modular system 20 according to an aspect of the disclosure is shown. The system 20 comprises a plurality of modules coupled together via magnetic fields generated by magnetic elements. Torque is transferred between two separate adjacent modules via forces imparted by the magnetic field. The magnetic coupling allows for synchronous motion to be maintained between adjacent modules.

In the illustrated arrangement, the system 20 comprises four (4) modules 22, although one of skill in the art will appreciate more or less may be present. As with Figure 2, the system 20 comprises a head 24, body 26 and tail fin 28. The head 24 comprises a single module 22, while the body 26 comprises three (3) modules 22. The modules 22 are coupled together via magnetic elements 32. Adjacent modules 22 have magnetic elements 32 with opposite polarities such that the generated magnetic field provides an attractive force to couple the modules 22 together. While not shown, each module 22 may include a ball bearing to provide for smoother more controlled rotation between adjacent module 22.

The system 20 additionally comprises a controller 30. In the illustrated arrangement the controller 30 is remote to the modules 22 of the head 24, body 26 and tail 28. However, one of skill in the art will appreciate the controller 30 may be located in one or more of the modules 22. The controller 30 controls operation of components of the modules 22 as will be described. Further, one of skill in the art will appreciate the controller 30 may absent from the system 20. In other words, the modules 22 may be autonomous such that no remote control is present. Sensing and data processing may be performed within the modules and the modules may operate to complete assigned tasks independently.

Each of the modules 22 comprises a housing having one or two magnetic elements 32, 34 therein. The magnetic elements 32, 34 have equal and opposite polarities to generate a force between modules 22 via the magnetic field generated by the elements 32, 34. The magnetic element 32, 34 pairs form magnetic couples to couple the modules 22 together and transfer torque to impart motion of entire modular system 20 (excluding the controller 30). The magnetic elements 32, 34 have generally arcuate profiles which match the curved end faces of the housing of the respective module 22. A joint is formed between magnetic elements 32, 34 of adjacent modules 22. Each joint is smaller and lighter than joints of conventional modular systems.

Figures 5 and 6 illustrate the external components of the modules 22 in more detail. Some of the modules 22 have been omitted from Figures 5 and 6 for clarity. Adjacent modules 22 are coupled together with a rotation angle between the modules 22 spanning a load angle 0.

A module 22 of the head 24 comprises a housing having a generally cuboid shape. In particular, the housing has an elliptical prism shape. The housing has two curved end faces or surfaces. A magnetic element 32 is positioned proximate one of the curved end faces as shown in Figure 3. The magnetic element 32 is adjacent the magnetic element 34 of an adjacent module 22 of the body 26.

The housing of the module 22 of the head 24 is formed of various components as illustrated in Figure 6. The housing comprises a head frame 42 having a front window 40 forming a front curved surface of the housing. The head frame 42 is connected via a flange 44 to an electronic housing 46 which houses the electronic components of the module 22 as will be described. The electronic housing 46 is connected on one end to the head frame 22 via the flange 44, and on the other end to a joint housing 48 via a flange 44. The joint housing 48 contains the magnetic element 32. The joint housing 48 is sealed via joint caps 50 on either end of the joint housing 48 which also serve to guide an adjacent module 22 of the body 26 for coupling with the module 22 of the head 24.

While not shown in Figure 6 for clarity, the magnetic element 32 is mounted on a rotatable shaft within the joint housing 48. Rotation of the shaft imparts the BCF motion between the modules 22.

A module 22 of the body 26 comprises a housing having a generally cuboid shape. The housing has two curved end faces or surfaces. A magnetic element 32 is positioned proximate one of the curved end faces, with another magnetic element 34 positioned proximate the other curved end face. The magnetic element 34 is adjacent the magnetic element 32 of the adjacent module 22 of the head 24. The magnetic element 32 is adjacent the magnetic element 34 of another adjacent module 22 of the body 26, or the tail fin 28.

A housing of a module 22 of the body 26 is formed of various components as illustrated in Figure 6. The housing comprises a magnet housing 52 which has a curved end face, i.e., one of the curved end faces of the housing. The curved end face has a profile which matches or mates with the profile of the joint housing 48 of the adjacent housing of the module 22 of the head 24. The magnetic element 34 is positioned proximate the curved end face of the magnet housing 52. In particular, the magnetic element 34 is coupled to an internal surface of the end face such that the magnetic element 34 is aligned with the magnetic element 32 to generate a magnetic field between the modules 22. The magnet housing 52 is connected to an electronic housing 46 which houses the electronic components of the module 22 as will be described. The electronic housing 46 is connected to a joint housing 48 via a flange 44. The joint housing 48 contains a magnetic element 32. The joint housing 48 is sealed via joint caps 50 on either end of the joint housing 48 which also serve to guide an adjacent module 22 of the body 26 for coupling with the module 22 of the head 24.

As with the module 22 of the head 24, the magnetic element 32 of the module 22 of the body 26 is mounted on a rotatable shaft within the joint housing 48. Rotation of the shaft imparts the BCF motion between the modules 22.

A module 22 of the tail fin 28 comprises a housing having a generally cuboid shape. The housing has one curved end face or surface. A magnetic element 34 is positioned proximate the curved end face. The magnetic element 34 is adjacent the magnetic element 32 of the adjacent module 22 of the body 26.

A housing of a module 22 of the tail fin 28 is formed of various components as illustrated in Figure 6. The housing comprises a tail main frame 52. The tail main frame 52 has a curved end face, i.e., one of the curved end faces of the housing. The curved end face has a profile which matches or mates with the profile of the joint housing 48 of the adjacent housing of the module 22 of the body 26. The magnetic element 34 is positioned proximate the curved end face of the tail main frame 52. In particular, the magnetic element 34 is coupled to an internal surface of the end face such that the magnetic element 34 is aligned with the magnetic element 32 within the joint housing 48 of the adjacent housing of the module 22 of the body 26 to generate a magnetic field between the modules 22. Connected to the tail main frame 52 is a tail fastening bar 54 which forms another curved end face of the housing of the module 22 of the tail fin 28. A tail plate 56 is affixed to the tail fastening bar 54 and oscillates during BCF motion of the modules 22.

The tail plate 56 may be exchangeable such that it can be detached and replaced with a tail plate 56 of different or the same materials or dimensions.

The electronic housing 46 comprises a variety of electronic components as illustrated in Figure 7. Figure 7 illustrates an electrical schematic diagram of the components in the electronic housing 46. The components may be mounted on a printed circuit board (PCB). The electronics comprise a motor 60, e.g., a servo or servomechanism. The motor 60 is connected to a shaft of the module to rotate the shaft and the magnetic element 32 connected to the shaft. The motor 60 may be connected to the shaft via a timing belt.

The electronics further comprise a breakout board 62, microcontroller 64, batteries 66, battery management system (BMS) 68, charging coil 70, switch 72, power diodes 74, 76, Zener diode 78, and capacitor 80.

The electronics are built around the microcontroller 64 which is powered by the batteries 66. The motor 60 is powered by the microcontroller 64 via power from the batteries 66. The motor 60 power level is measured by the breakout board 62 which is also powered by the microcontroller via the batteries 66. Wireless charging is possible via the wireless charging coil 70. The Zener diode 78, capacitor 80 and power diodes 74, which in this arrangement are Schottky diodes, protect the microcontroller 64 from over voltage and reverse current transients caused by rapid motor 60 movement. The switch 72 allows for the electronics to be turned off during wireless charging of the batteries 66 via the charging coil 70.

Specifically, the motor 60 is electrically connected to the breakout board 62, power diode 74, Zener diode 78, capacitor 80, charging coil 70 and BMS 68. The breakout board 62 is electrically connected to the motor 60, capacitor 80, Zener diode 78, power diode 76, charging coil 70, BMS 68 and microcontroller 64. The microcontroller 66 is electrically connected to the motor 60 via the switch 72 and power diodes 74, 76. The microcontroller 64 is further electrically connected to the BMS 68 and charging coil 70. The BMS 68 is electrically connected to the batteries 66 and charging coil 70. The Zener diode 78 and capacitor 80 are electrically connected in parallel.

Wireless communication for maintaining remote control of the module 22 via the controller 30 is provided by the microcontroller 64 as the microcontroller 64 includes a communication module.

No magnetic sensors, such as a current hall sensor, were used to avoid any interference between the sensor and the magnetic field of the magnetic elements 32, 34.

While particular electronics have been illustrated, one of skill in the art will appreciate that other configurations are possible. For example, the breakout board 62 may not be included.

Motion between adjacent modules 22 will now be described in more detail with references to Figures 8, 9a and 9b. Two adjacent modules 22 are illustrated in part in Figure 8, for example a module 22 of the head 24 and a module 22 of the body 26. Synchronous mechanical coupling between the physically separate modules 22 is achieved by means of magnetic attraction between the magnetic elements 32, 34 present in the adjacent modules 22. In the illustrated arrangement, the magnetic elements 32, 34 generate the magnetic attraction. Magnetic couples are formed between the elements 32, 34 of a driving module and a driven module. The driving module represents the ascending body element in which the magnetic element 32 is connected to a rotating shaft. The driven module represents the descending body element in which the magnetic element 34 is connected to the curved end face of the housing of the module 22. Synchronous motion is maintained via restoring torque relative to the displacement angle between the two modules 22. When the load difference between the two modules 22 exceeds a maximum magnetic torque, coupling slip occurs. Designing the magnetic couple to provide sufficient coupling strength for a particular application avoids or limits such coupling slip. In addition to torque transmission, magnetic attraction between the elements 32, 34 aligns and holds adjacent modules together with the descending module element resting atop the ascending module element’s ball bearing.

As shown in Figure 8, the magnetic elements 32, 34 are positioned within a limited arc space of the curved end face of the housing of the adjacent modules 22. The magnetic elements 32, 34 are not positioned around an entire shaft internal to the module 22. This reduces the weight of the module 22 avoiding large interlinked joints. Further, this permits the modules 22 to decouple when experiencing extreme external loads.

The magnetic elements 32, 34 have alternating polarity. As shown in Figures 9a an d9b each magnetic element 32, 34 comprises both north and south polarities. The coupling between adjacent modules provides for one degree of freedom (DoF) between adjacent modules to enable the shaping of a travelling wave in the longitudinal axis (the common plane) of rotation of joints between adjacent modules 22.

While the magnetic elements 32, 34 have been illustrated as single unique elements, one of skill in the art will appreciate multiple magnetic sub-elements may form a single magnetic element 32. For example, each element 32, 34 may comprise a plurality of sub-elements forming an array, for example a Halbach array. As will be described with reference to an alternative embodiment, a magnetic element may also be curved in two dimensions forming a Halbach cylinder or Halbach Sphere. Halbach arrangements increase the magnetic field generated by the magnetic element thereby increasing the coupling between adjacent modules.

Figure 9a illustrates the force vector in the x direction, for a normal distance Ax, for a single magnetic couple between elements 32, 34 as shown in Figure 8. Figure 9b illustrates the force vector in the y direction, for a perpendicular distance Ay, for a single magnetic couple as shown in Figure 8. The holding force Fx between magnetic elements 32, 34 maintains the modules in alignment. The module 22 is designed for a maximum shear force Fy to avoiding the mentioned slipping when transferring torque between modules.

Decoupling will appear when a pull force between magnet elements 32, 34 exceeds the magnetic couples normal force, e.g., Fy. Under normal operating conditions decoupling does not appear, as there is a push force, e.g., Fx, generated between the coupled modules 22 when the system is moving. Additionally the characteristics of the viscous, self-supporting nature of water in the environment of the system 20 may maintain coupling between modules 22.

Additionally, as shown in Figure 9a, the magnetic elements 34 have dimensions W, L and T for width, length and thickness, respectively.

An approximation model was developed to support the design of the modules 22 to maintain the maximum transferable torque and determine the maximum shear force. The maximum transferable torque, Tmax, is approximated by a function of the number of magnet couples of the entire system 20, n, the maximum sheer force, Fy.max, and the radius, r, between the joint centre points, and the half distance between the two magnet elements 32, 34, z/2. Thus, Tmax is given in equation 1 below. -max ~ F _{x max} ■ r + - ■ n, (1)

The magnetic forces Fy.max and Fx are calculated using equations known in the art.

Fx can be approximated as per equation 2 below. d ²

Fx = x+d _e VF ₀ , (2) where, F0 is the force Fx at x=0, and the variable de is defined as Fx (x=0, x=de ) = 1/4 F0.

The orthogonal component of the maximum shear force in the X-Y plane is approximated by equation 3 below.

Here, L1/L2 is the length ratio between magnet couple and remains equal to 1. De values for F(x=0) and 1/4 F(x=0) are computed via magnetostatic finite element method (FEM) simulation.

As shown in equations (2) and (3), the coupling strength is directly related to the magnet strength, dimension, and the normal distance between magnet couples. When the modules 22 are coupled together via magnetic attraction between the elements 32, 34, the system may form a traveling wave via oscillation motion of its joints at a phase difference according to their body position. Each joint follows a sinusoidal oscillation according to equation 4 below.

Where 0 is the pitching angle, t is time, A(s) and (p(x) define the amplitude envelope and phase offset which depend on the body position. Control variables for amplitude magnitude, wavelength, offset and frequency, respectively, are ca, cp, cs and f. Further changes to the wave shape can be made using the amplitude envelope equation A(x). The maximum frequency is given by fmax < W/A(L)2TT with co = 60/0.2 [deg/sec].

In operation, the module 22 of the head 24 is actuated to propel the system 22 in an environment, e.g., an underwater environment. The controller 30 sends a control signal to the microcontroller 64 to actuate the motor 60 to propel the module 22. The motor 60 rotates and transfer this rotating motion via the timing belt to a shaft on which the magnetic element 32 is mounted. The shaft rotates and the magnetic couple formed between the magnetic element 32 of the module 22 of the head 24, and the magnetic element 34 of the module 22 of the body 26 impart movement on the module 22 of the body 26. Continuing rotation in opposite directions imparts oscillation of the module 22 to move through the environment via BCF motion. The module 22 adjacent the module 22 of the head 24 is similarly actuated to rotate a shaft on which magnetic element 32 is mounted to transfer torque to the next adjacent module 22. The final module 22 of the tail fin 28 oscillates via torque transference between the elements 32, 34 and sheds vortices at the trailing end of the system.

While operation has been described for a general system 20, an experimental prototype was built and tested. The prototype modular system 20 comprises four (4) modules, i.e. , n=4, having an inner radius, Ri, of 32 mm and an outer radius, Ro of 37 mm. The inner radius was the distance from the centre of a shaft within a housing of a module 22 to the outer face of the housing of the module. The outer radius was the distance from the centre of a shaft within a housing of a module 20 to the outer face of the housing of the adjacent module 22. The magnetic elements 32, 34 are cuboid neodymium magnets. Specifically, the magnetic elements 32, 34 are NdFeB cuboid magnets of dimension L = 40 mm, W = 10 mm and T = 5 mm. The total length of the prototype system 20 was 907 mm, with a width of 70 mm and a height of 110 mm. A 6 mm distance between magnetic elements 32, 34 was set such that the normal force between magnetic elements 32, 34 was calculated as Fx = 19.2325 N and the maximum shear force was calculated as Fy = 22.874 N based on equations 2 and 3. The maximum transferable torque was calculated as Tmax = 2.4533 Nm based on equation 1. At a load angle of 14 degrees maximum torque of Tmax = 2.6315Nm.

The motor 60 used in the prototype comprises a Hitec HS-646WP Servo. The breakout board 62 comprises a Adafruit INA260. The microcontroller 64 comprises an Arduino NANO 33 BLE. The breakout board 62 was powered via the Arduino’s 3.3v pin and communicates via I2C bus. The batteries 66 comprise two 18650 batteries connected in series via a 2S BMS 68 resulting in 3000mAh capacity and a supply voltage between approximately 7V - 8.4V. The Zener diode 78 comprises a 10 V Zener diode. The power diodes 74, 76 comprise Chottky diodes having a rating of 2A-3A and 500mA-3A, respectively. The charging coil 70 used comprises a 12-volt TDK WRM483265-10F5- 12V-G wireless charging coil. The Bluetooth Low Energy (BLE) module of the Arduino was used to provide communication was the controller 30.

Each joint between adjacent modules 22 is driven via a HTD timing belt connected to a pulley of the motor 60. This allows for a maximum rotation angle of ±35 degrees between two modules 22 given by the mechanical constraint of intersecting adjacent modules 22, and the gear ratio between pulley, shaft, and motor 60.

The prototype system 20 was manufactured using a Digital Light Processing - Stereolithography (DLP-SLA) printer: ANYCUBIC Photon Mono (ANYCUBIC 2022). Such a printer allows for creating parts with a tolerance of 50 micron. This printing method was used to produce durable 3D objects by solidifying UV activated resin. A standard translucent resin was used with the properties listed in Table 1. Table 1 - Properties 405nm UV resin

To avoid the cup effect (printing closed cavities that lead to a pressure difference resulting in part deformation), the modules 22 were broken down into six (6) parts which were later assembled permanently using an epoxy resin or via threaded inserts and screws to allow for assembly access. All 3D printed parts were coated with a UV blocking spray to stop the materials from further solidifying when exposed to UV light, for example during transport, and extend the longevity of the parts. The interface between parts is watertight and sealed via six (6) M3 screws. The module 22 further includes a surface seal made of expanded DA320 closed cell sponge material.

Modules 22 were balanced and ballasted individually to allow for flexible extension or reduction of the modules 22 of the body 26. Balancing and ballasting of the modules 22 was achieved by adding weights at the bottom of each module 22.

Various parameters of the prototype system 20 were altered to determine optimum operating conditions. The results of these parameters variations are illustrated in Figures 10a and 10b. In particular, Figure 10a illustrates the force curves at various distances of the described prototype system 20 with the nominal distance being at separation of 6 mm. Figure 10b illustrates the torque for different load angles with the torque maximized at approximately 14 degrees.

Figure 11 illustrates the magnetic field between the magnetic elements 32, 34 at a load angle of 14 degrees. The connecting field lines between magnet couples are visible, as is the minimum magnetic field intensity between magnets of the same polarity.

The prototype modular system 20 was tested. The manoeuvrability and thrust generation of the system 20 was evaluated during testing. The testing was conducted in a 3.5 m by 9 m water tank of still water. The head 24 and each joint between adjacent modules 22 were fitted with detachable reflector coordinate systems that are detected by a Qualisys motion capture system to record the modules 22 free-swimming trajectory and body motion. The system 20 was controlled in an open loop real-time serial communication via MATLAB Simulink. A constant amplitude envelope, A ) = c _a , was used for free swimming, and a linear amplitude envelope, A(s) = was used for thrust performance evaluation. At the tip of the head 24, - = 0, while at the trailing edge of the tail fin 28, - = 1. The resulting individual joint positions between adjacent modules 22 were found to be: s _x = 0.248, s ₂ = 0.444, s ₃ = 0.642.

Figures 12a and 12b illustrate the discretised rigid body wave shape of the modules 22 over a continuous wave shape. Figure 12a illustrates the discretised rigid body wave shape at a constant amplitude of Ca = 10, while 12b illustrates the discretised rigid body wave shape at a constant amplitude of Ca = 15. The wavelength is kept at A=1 and controlled by cp=1.

The modular system 20 was deployed in the tank and swimming was observed. Figure 13 illustrates module 22 trajectory of the prototype magnetically coupled modular system 22 during swimming. This trajectory was observed with a constant amplitude envelope at ca=10, equal joint offset of 25 degrees, and frequency of 1 Hz. This configuration is close to the maximum camber of the overall body 26 of the modules 22. Additionally, the roll, pitch and yaw of the modules 22 was observed. Figures 14a, 14c and 14e illustrate the roll, pitch and yaw for 3.5 circles, respectively, while Figures 14b, 14d and 14f illustrate the roll, pitch and yaw for one full circle. The dynamic roll and pitch amplitude is recorded to be ca. 2.5 and 2 degrees, respectively. Static pitch and roll amplitude is recorded at ca. 8 and 10 degrees, respectively.

The time for one full circle is approximately 35 seconds resulting in an angular velocity of 10 degrees per second. Starting from a resting position, Figure 13 shows the modules 22 reach a stable circle trajectory. The tip of the head 24 follows a smaller radius of ca. 300 mm and the position at the tail fin 28 joint a radius of ca. 1400mm.

Thrust performance of the prototype system 20 was also evaluated with three different tail plate 56 materials, e.g., Carbon fibre, Foamex and acrylonitrile butadiene styrene (ABS). This was evaluated across 12 different cases in which: case 1-4 carbon fibre, case 5-8 Foamex, and case 9-12 ABS were used. The three different tail plate 56 materials were tested for 2 amplitudes (10 and 15 degree) and 2 frequency (0.75 and 1 Hz) each (4 cases per materials). In other words, for the carbon fibre tail plate 56 four cases were tested:

Case 1: Amplitude 10 Frequency 1

Case 2: Amplitude 15 Frequency 1

Case 3 Amplitude 10 Frequency 1.5

Case 4: Amplitude 15 Frequency 1.5

This was repeated for the other two materials resulting in the testing of 12 cases in total.

To measure the thrust generation, a test methodology that resembles the bollard pull test, popular in the assessment of ship forward thrust generation, was used. Strain gauges were used to measure applied force in normal and side direction. The modules 22 were connected via an adapter with the head 24 being fixed to a strain gauge bar with one DoF to allow for the wave shape to start at the tip of the head 24. Force data was processed via a lowpass filter to cut out frequencies above 2.5 times the actuation frequency.

For equal measurements between cases and to ensure perpendicular alignment of the modules 22 towards the strain gauge bar, sample data is taken at the point where the side forces over one oscillation cycle T = 1/f is closest to zero ~ .F _V « 0. At this point instantaneous force curves are compared, and net thrust is recorded. The recorded data was compared in terms of frequency and amplitude increase as well as difference

Figure 15a illustrates measured net thrust and pairs are compared for changes in undulation frequency. For all cases (i=0,4,8), an increase in wave frequency results in an increase in net thrust. While for case pairs 6-8 the increase is marginal, the difference between case pairs 2-4 increases twentyfold. For all cases, as expected, an increase in wave frequency leads to an increase in instantaneous force frequency.

The instantaneous forces of case pair 9-11 is illustrated in Figure 15b which shows that the side force remains stable in magnitude for increasing frequency while the net thrust force increases. Figure 16a illustrates measured net thrust and pairs are compared for changes in undulation amplitude. For all but one case an increase in amplitude results in an increase in net thrust. Further, an observed side force is present which can be seen in the comparison of the instantaneous forces of case pair 3-4 in Figure 16b. While the general force curves show resemblance, the amplitude of side and thrust force increases with the increase of actuation amplitude.

Further changing the tail plate 56 between the described materials, presents differences in force magnitude as well as differences in wave shape.

The fluctuating wave shape of softer materials at lower frequencies indicates a more complex fluid-structure interaction.

Comparing the instantaneous force curves of the three materials at constant amplitude and frequency shows resembling curve shapes side forces in Figure 17b and Figure 17d, and complex force curve in Figure 17a and Figure 17c, suggesting an influence of the actuation frequency. Comparison of net thrust in Figure 18 does not reveal a clear advantage for any of the three materials for the tested geometries. However, a trend for improved thrust performance with increased stiffness is visible which can be explained by the rather long geometry of the tested tail fins.

While a particular arrangement of the magnetically coupled modular system 20 has been described, one of skill in the art will appreciate other configurations are possible. Other exemplary arrangements of the modular system are illustrated in Figures 19-23b.

Figures 19 and 20 illustrate an arrangement of a magnetically coupled modular system 120. Reference numerals of the system 120 corresponding to like elements of the described modular system 20 have been incremented by 100. In the illustrated arrangement the system 120 comprises seven (7) modules 122. The module 122 of the head 124 comprises a single magnetic element 132, and the module 122 of the tail fin 128 comprises a single magnetic element 134. The modules 122 of the body 126 comprise magnetic elements 132, 134.

As shown in Figures 21a-c, the magnetic elements 132, 134 have a generally spherical cap shape. In other words, the magnetic elements 132, 134 have a spherical shell sector shape. Such a shape may allow for the magnetic elements to transfer torque not only one DoF as described, but also in a second perpendicular DoF. The system 120 may allow for torque transfer not only in the yaw axis, but also in the pitch axis. This may allow the system 120 to control propulsion of the modules 122 and decent/ascent of the modules 122.

Given the shape of the magnetic elements 132, 134 the housings of the modules 122 may have similarly spherical end faces proximate the magnetic elements 132, 134. Further, as shown in Figure 21c, the magnetic elements 132, 134may be separated by the housing walls 190 of the housings of the adjacent modules, as well as a ball bearing spherical cap 192 between the adjacent modules. In the illustrated arrangement, the ball bearing spherical cap 192 comprises a curved surface with a plurality of recesses each housing a ball bearing.

While a particular arrangement of the magnetically coupled modular system 20 has been described, one of skill in the art will appreciate other configurations are possible. Another exemplary arrangement of the modular system is illustrated in Figure 22. Figure 22 illustrates an embodiment of a magnetically coupled modular system 220. Reference numerals of the system 220 corresponding to like elements of the described modular system 20 have been incremented by 200.

In the illustrated arrangement the system 220 comprises six (6) modules 222. The module 222 of the head 224 comprises a single magnetic element 232. The modules 222 of the body 226 comprise magnetic elements 232, 234. The magnetic elements 232, 234 have the same generally spherical cap shape described with respect to Figures 21a-c.

In this arrangement, one module 222 of the body 226 is connected to a base 294 while the module 222 of the head 224 is connected to an end effector 296. The module 222 connected to the base 294 is at the opposite end of the system 220 with respect to the module 222 connected to the end effector 296. The end effector 296 allows the system 220 to complete a variety of tasks depending on the exact end effector 296. For example, the end effector 296 may comprise a welding tool such as a welding torch for subsea welding. Alternatively, or additionally, the end effector 296 may comprise a gripper such as a mechanical gripper, a pneumatic gripper, a magnetic gripper or suction cup. This allows the system 210 to grip and interact with objects in a subsea environment. The end effector 296 may be integral with the module 222 of the head 224 or connected to the module 222 using known connectors.

The base 294 may be a fixed base. Alternatively, the base may be movable such a robot or ROV. Additional exemplary bases 294 include offshore structures such as offshore structures such as offshore wind turbine, and oil and gas platforms. The base 294 may be integral with its associated module 222 or may be connected to the module 222 using known connectors.

While particular arrangements of the magnetically coupled modular system 20, 120, 220 have been described, one of skill in the art will appreciate other configurations are possible. Another exemplary arrangement of the modular system is illustrated in Figures 23a-b. Figures 23a-b illustrate an embodiment of a magnetically coupled modular system 320. Reference numerals of the system 320 corresponding to like elements of the described modular system 20 have been incremented by 300.

In the illustrated arrangement the system 320 comprises seven (7) modules 322. The module 322 of the head 324 comprises a single magnetic element 332. The modules 322 of the body 326 comprise a plurality of magnetic elements 332, 334. The plurality of magnetic elements 332, 334 have the same generally spherical cap shape described with respect to Figures 21a-c with the exception that at least one of the magnetic elements 332 and 334 are formed from a plurality of segments. The magnetic elements 332, 334 of adjacent modules 322 encircled within the circle A are illustrated in greater detail in Figure 23b.

As shown in Figure 23b, the magnetic elements 332 and 334 within the modules 322 comprise a plurality of magnetic elements, i.e., magnetic element segments. Specifically, magnetic elements segments 332a, 332b, 332c in one module 322 and magnetic elements segments 334a, 334b, 334c in an adjacent module 322. The magnetic elements segments 332a-c form a generally arcuate (convex) shape which spans the end face of the module 322. Similarly, the magnetic elements segments 334a-c form a generally arcuate shape (concave) which spans the end face of the adjacent module 322. While the magnetic elements segments 332a, 332c, 334a, 334c are permanent magnets similar to the previously described magnetic elements 132, 134, the magnetic elements segments 332b, 334b are electromagnets which from a transmitter/receiver combination.

Controlling the magnetic field generated by the electromagnets communicates a data or power signal between adjacent modules 322. Inductive data transfer, also known as wireless data transfer or inductive data communication, involves using electromagnetic fields to transmit data wirelessly between the modules 322. The process includes modulation of the data, using a transmitter and receiver with magnetic elements 332b, 334b (e.g., coils) that generate and capture electromagnetic fields, inductive coupling between the coils to transfer the data, and data processing at the receiving end (adjacent module 322).

As signal communication is accomplished via wireless or inductive data communication, no cables need to run between modules 322 ensuring the modules 322 are watertight thereby protecting components within the modules 322.

Signal transmission may be controlled by a controller remote to the system 320, e.g., controller 30, or within one of the modules of the system 320. Further, the signal may be communicated from one module 322 to another module 322 for communication to an external receiver. In this way data collected at one module can be communicated to any other module and communicated to locations remote to the system 320.

The data signal may comprise telemetry data related to the modular system 320, and/or sensor data collected by sensors associated with the modular system 320. The power signal may transfer electrical power from one module 322 to an adjacent module 322. This may ensure that one module 322 which is otherwise low on power may continue to operate with electrical power transferred from an adjacent module 322.

While particular modular systems 20, 120, 220, 320 have been described, one of skill in the art will appreciate modifications are possible. For example, the modular systems may additionally comprise a decoupling mechanism for decoupling adjacent modules. The decoupling mechanism is actuated to decouple adjacent modules. Such decoupling may assist in replacing a particular modules or set of modules in the event replacement is necessary. Additionally, such decoupling may allow for the modular system to continue to operate should one or more modules become stuck in an environment, e.g., stuck under an underwater rock.

A variety of decoupling mechanisms are possible. Figures 24a-b illustrate a sequence of steps for decoupling adjacent modules of a magnetically coupled modular system. In particular, Figure 24a illustrates operation of an exemplary decoupling mechanism. In this arrangement, adjacent magnetic elements, e.g., permanent magnets, form a magnetic couple between adjacent modules with an attracting magnetic force as illustrated in Figure 24a-1. To decouple the adjacent modules, the decoupling mechanism rotates one of the magnetic element 90 degrees as illustrated in Figure 24a-2. Opposite poles of the adjacent permanent magnets are no longer aligned and a magnetic attractive force is no longer present. Further, the decoupling mechanism may further rotate the magnetic element an additional 90 degrees in the same direction (180 degrees total from the original orientation) such that the same poles of adjacent magnets are not aligned, e.g., North-North or South-South. The resulting repelling force may decouple the associated adjacent modules.

The decoupling mechanism may accordingly comprise a rotation means such as a motor, servomechanism, rotary arm, etc.

Alternatively, if one or more of the magnetic elements 32, 34, 132, 134, 232, 234, 332, 334 comprise an electromagnet, the decoupling mechanisms may simply be any means for de-energising the electromagnetic coil of the electromagnet. For example, a switch may de-energise the coil. The energised coil is shown in Figure 24b-1, with the de-energised coil illustrated in Figure 24b-2. When the coil is de-energised, no magnetic field is generated by the coil and no magnetic couple is present between the coil and an adjacent permanent magnet as shown in Figure 24b-2.

Any of the described modular systems may be used in a variety of applications including applications in the oil and gas field. The described modular systems may allow for internal components to be protected from water damage given the watertight structure of the modules. For example, electronics within the modules may be protected from water damage. This may allow for faster, cheaper and more straightforward certification of the modular system for a variety of use cases including offshore renewable, and oil and gas applications. It should be understood that the examples provided are merely exemplary of the present disclosure, and that various modifications may be made thereto.