Search

This paper presents the ongoing Horizon Europe Twinning project Montenegrin Centre for Underwater Sensor Networks (MONUSEN) and provides an overview of the activities that have taken place during the first ten months of the project and future plans. MONUSEN strives to create collaborative conditions for the University of Montenegro to trace a clear excellence trajectory in the field of Underwater Sensor Networks (USNs). This will be achieved by twinning with European research-intensive institutions with strong expertise in this field: National Research Council of Italy, University of Zagreb Faculty of Electrical Engineering and Computing, and Newcastle University. The project has four main lines of action: scientific knowledge transfer, joint research on the design of efficient and secure USNs, research management capacity building, and broad networking with USN research stakeholders and industry. While all envisioned objectives of the project are listed, the paper primarily focuses on the research results and plans, and strategic measures for increasing scientific involvement and visibility.

Refereed/Peer-reviewed Identifying the provenance of marine animals yields fundamental data on a species’ ecology and life history and enables the geolocation of individuals for food forensic applications. However, many provenance methods are resource-intensive and developed on a species-specific basis. Here we discuss how natural chemical markers with predictable spatial patterns and common expression among species could be used as provenancing tools that are universally applicable to many species. To demonstrate the universal marker concept, we focus on stable oxygen isotopes bound within calcium carbonate biominerals. In doing so, we compiled a global database of oxygen isotope values to illustrate universal latitudinal patterns across key marine taxa. We then discuss how this concept could be integrated within a spatial modelling framework and applied to tackle the environmental challenge of seafood provenance. By developing universal markers we have the opportunity to trace a greater range of species to support their conservation and management.

International audience; This article focuses on the active management of the umbilical of a Remotely Operated Vehicle (ROV) for shallow water exploration. The objective is to increase the ROV maneuverability by exploiting the mechanical model of the cable that links the ROV to an Unmanned Surface Vehicle (USV). The efforts applied on the umbilical are studied in simulation. The numerical models implemented under Simulink TM and Vortex TM are used to define new strategies of control for the winch, the USV and the ROV in order to manage the umbilical.

This paper describes the trajectory tracking of an underactuated autonomous underwater vehicle (AUV) with three control inputs (surge, yaw and pitch moment) that operates in the presence of time-varying disturbances. The AUV kinematics are described in global coordinates as a Hamiltonian system on the Lie group SE(3) and the boundary-value problem arising from the geometric framing of Pontryagin’s Maximum Principle is applied to the vehicle kinematics. This 6-dimensional boundary value problem is solved using a numerical shooting method and a novel semi-analytical Lie group integrator. The integrator uses Rodrigue’s formula to express the exact solution of the solution curves, is symplectic and preserves energy and momentum. Inverse dynamics is applied to construct an inner-loop controller, which accounts for constraints on maximum torque and force via time reparametrization. This inner-loop control, which would drive the AUV along the reference trajectory in perfect conditions, is combined with a disturbance observer to construct an outer-loop controller, which ensures stability in the presence of bounded disturbances. Simulation results complete the work.

Simple control solutions for steering underactuated ships have been seldom studied in literature. This paper provides a control method for automatic steering of underactuated ships in presence of disturbances and in uncertain environmental conditions. A mathematical model of ship dynamics is developed and validated. Our control method involves introduction of a preparation phase consisting of three algorithms. Waypoints leading to every desired set-point are defined and a continuous Dubins path is generated between these waypoints. A second-order motion profile is assigned to the path to suggest the speed with the best timing for the voyage. The control objective is reformulated from a tracking problem to a regulating problem by changing coordinates of the reference signal. PD-controllers are employed in closed loop to reduce position and heading error. The controller parameters are set in the design phase and do not need additional tuning for different trajectories and ship parameters. Weather information together with the planned motion profile are used in a feedforward controller design to achieve better disturbance rejection and higher accuracy. Performance and robustness of the design are evaluated in simulation by Course-keeping and Course-changing experiments in extreme and uncertain environmental conditions. While the developed control method is simple compared to the methods in literature, it can still achieve quite satisfactory steering performance.

Modern computers with specialised software are able to simulate oceans with waves and sea currents, and the action of wind, gravity, ships and other vehicles. The high-level programming languages that are used in this type of software can read information from navigation devices connected to the computer (e.g., via serial ports), and proceed to use the raw data in control algorithms. More and more desktop software and simulators can use data from additional electronic devices such as pressure sensors, temperature sensors, etc. Thus, it is possible to conduct real-time communication with a PLC (programmable logic controller) and use it in simulators. In this article, a user interface designed in Unity3d is presented. The user interface was able to read data from navigation devices, which were used in a ship positioning control algorithm. Verification of the algorithm occurred during research on a real ship, which used an anchor-based positioning system. Using data obtained on the real ship, a mathematical model of anchor winches was developed. Next, the mathematical model was implemented in the simulator developed in Unity3d. The simulator contained the same environmental conditions as during the research on the real ship. The mathematical model of anchor winches and implementation developed in the simulator will allow for future research on anchor-based positioning systems (e.g., in different environmental conditions). The research resulted in a shift of the ship’s position by 26.3 m under 280 degrees. The difference in arrival time to the target point between the real ship and the virtual ship was 19%, and the difference in position deviation was 330%.

Bathymetry retrievals from 2D, multispectral imagery, referred to as Satellite‐Derived Bathymetry (SDB), afford the potential to obtain global, nearshore bathymetric data in optically clear waters. However, accurate SDB depth retrievals are limited in the absence of “seed depths.” The Ice, Cloud, and land Elevation Satellite‐2 (ICESat‐2) space‐based altimeter has proven capable of accurate bathymetry, but methods of employing ICESat‐2 bathymetry for SDB retrievals over broad spatial extents are immature. This research aims to establish and test a baseline methodology for generating bathymetric surface models using SDB with ICESat‐2. The workflow is operationally efficient (17–37 min processing time) and capable of producing bathymetry of sufficient vertical accuracy for many coastal science applications, with RMSEs of 0.96 and 1.54 m when using Sentinel‐2 and Landsat 8, respectively. The highest priorities for further automation have also been identified, supporting the long‐range goal of global coral reef habitat change analysis using ICESat‐2‐aided SDB., Key Points Satellite‐derived bathymetry using passive sensors, requires elevation “seed points” to yield physically meaningful seafloor elevations.NASA ICESat‐2 laser altimetry provides a vertical reference for satellite‐derived bathymetry products.Operationally efficient ICESat‐2‐aided satellite‐derived bathymetry workflows hold promise for global assessment of benthic habitat change.

Satellite data and models suggest that oceanic productivity is reduced in response to less nutrient supply under warming. In contrast, anthropogenic aerosols provide nutrients and exert a fertilizing effect, but its contribution to evolution of oceanic productivity is unknown. We simulate the response of oceanic biogeochemistry to anthropogenic aerosols deposition under varying climate from 1850 to 2010. We find a positive response of observed chlorophyll to deposition of anthropogenic aerosols. Our results suggest that anthropogenic aerosols reduce the sensitivity of oceanic productivity to warming from −15.2 ± 1.8 to −13.3 ± 1.6 Pg C yr−1 °C−1 in global stratified oceans during 1948–2007. The reducing percentage over the North Atlantic, North Pacific, and Indian Oceans reaches 40, 24, and 25%, respectively. We hypothesize that inevitable reduction of aerosol emissions in response to higher air quality standards in the future might accelerate the decline of oceanic productivity per unit warming., Key Points Anthropogenic aerosol deposition alleviates the nutrient limitation in the oceansResponse of observed chlorophyll to anthropogenic aerosol deposition is modeledOver 1948–2007, the sensitivity of oceanic productivity to warming is reduced by 12.5%

Increasing input of Metal Engineered Nano Particles (MeENPs) in marine ecosystems has raised concerns about their potential toxicity on phytoplankton. Given the lack of knowledge on MeENPs impact on these important primary producers, the effects of Copper Oxide (CuO) ENPs on growth, physiology, pigment profiles, fatty acid (FA) metabolism, and oxidative stress were investigated in the model diatom Pheodactylum tricornutum, to provide suitable biomarkers of CuO ENP exposure versus its ionic counterpart. Diatom growth was inhibited by CuO ENPs but not Ionic Cu, suggesting CuO ENP cytotoxicity. Pulse Modulated Amplitude (PAM) phenotyping evidenced a decrease in the electron transport energy flux, pointing to a reduction in chemical energy generation following CuO ENPs exposure, as well as an increase in the content of the non-functional Cu-substituted chlorophyll a (CuChl a). A significant decrease in eicosapentaenoic acid (C20:5) associated with a significant rise in thylakoid membranes FAs reflected the activation of counteractive measures to photosynthetic impairment. Significant increase in the omega 6/omega 3 ratio, underline expectable negative repercussions to marine food webs. Increased thiobarbituric acid reactive substances reflected heightened oxidative stress by CuO ENP. Enhanced Glutathione Reductase and Ascorbate Peroxidase activity were also more evident for CuO ENPs than ionic Cu. Overall, observed molecular changes highlighted a battery of possible suitable biomarkers to efficiently determine the harmful effects of CuO ENPs. The results suggest that the occurrence and contamination of these new forms of metal contaminants can impose added stress to the marine diatom community, which could have significant impacts on marine ecosystems, namely through a reduction of the primary productivity, oxygen production and omega 6 production, all essential to sustain heterotrophic marine life.

In modern warships the electrical power and propulsion system is fundamental to the end capability of the vessel. The Type 26 Global Combat Ship will utilise an advanced CODLOG (Combined Diesel Electric or Gas Turbine) propulsion architecture. The integration of this advanced architecture poses a number of engineering challenges and risks. The general philosophy towards de-risking taken at BAE Systems Naval Ships is one of left shifting project risk, whereby risks are considered and mitigated at the earliest opportunity in the development lifecycle. The electrical power generation and distribution system for Type 26 is considered to pose one of the largest integration risks within the Power &Propulsion (P&P) System. There are electrical power and propulsion integration risks in areas such as the overall quality of power supply (QPS), ship performance during transition modes and diesel generator ramp rates. Another key risk is the physical, functional and control integration aspects of the P&P system, with each piece of equipment needing to be integrated with the wider P&P system and the overarching Power Management System. In this paper, the de-risking strategies that have been put in place to minimise risk in respect of the power and propulsion integration system for Type 26 are presented. Chiefly, these activities involve the development and utilisation of computer based mathematical models of the power and propulsion and electrical power systems, and the construction of shore based integration test facilities.

Development of Marine Autonomous Systems (MAS) has accelerated sharply in recent years. Government, academia and industry papers advising on the future of the maritime sector unanimously agree on the need for a regulatory framework to be established to enable the safe development, testing and operation of MAS. A regulatory framework must be developed which does not introduce constraints on the growth of MAS capabilities. This paper analyses the existing maritime regulations and proposes necessary changes to guide a process to develop regulatory requirements. Regulation development guidelines include a range of considerations including technical, legal and insurance/liability, where adherence is complex the development of an alternative MAS specific regulation or an explanation of how the existing regulation may be complied with by MAS is required. The proposed process links MAS technical capabilities to appropriate testing regimes and associated supporting bodies of evidence and recommends testing regimes which combine simulation with demonstrations and real-world tests and leading to demonstrable levels of safety. Establishing a regulatory framework for MAS is a challenging task, but a key enabler to the effective adoption of autonomous vessels in the maritime sector. Through proposing changes to the current process and a new approach for MAS, this paper aims to take tangible steps in developing a regulatory solution.

There are a wide range of Unmanned Underwater Vehicles (UUVs) in operation today and they already include a vehicle with 45te displacement. Technology developments in underwater communications, autonomy, and battery and power systems, driven in part by the automotive industry, mean that many previously perceived barriers/blockers can be overcome, and underwater capability opportunities realized. These opportunities include distancing operators from threats, reducing cost, but also reducing manpower requirements for mundane operations. Many nations require these roles in territorial waters, the extended neighbourhood and expeditionary operations. This and payload requirements conspire to drive future vehicles into a less well understood design bracket between current small UUVs and manned diesel-electric submarines. This paper describes some of the resultant Large UUV design challenges and opportunities such as shorter development cycles, the risk of an unstable design space between relatively simple expendable UUVs and very complex manned submarines, the need for reliability and applicable rules and standards. It describes a design methodology that applies light-touch system engineering principles to vehicle concept development to address these challenges. This is supported by development and description of an illustrative Large UUV design which provides a good balance of cost, complexity, and capability.

The level of maturity of maritime autonomous vehicles makes the deployment of networks of vehicles costeffective with an increasing number of applications that today require the usage of autonomous robots. To maximise operational effectiveness, one critical decision variable that has a direct impact on both the cost and performance, lies in how to properly place the different robots/sensors in the target environment. The number of assets, the dedicated communication networks, can contribute a significant portion of the overall cost and their placement determines the overall mission time and the associated coverage area. The ability to quickly allocate the available vehicles to one specific area, to monitor the mission performance, and to understand the quality of the data gathered would represent a key capability to speed up the uptake of the technology even more. This paper aims at bridging this gap, and provides a solution to efficiently schedule multi-vehicle, multi-days and large areas campaigns. The output of the campaign planner is a set of goals (e.g. areas to survey, targets to reacquire), which can then be allocated to the vehicles for execution. Finally, to maximise vehicle interoperability this paper also report an automated translator from high-level mission plans to vehicle to vehicle specific commands. Results are reported through simulations.

The integration of renewable energy sources in power systems, specially wind energy, is growing as environmental concerns arise in society. Nevertheless, the low amount of viable sites onshore or in shallow waters restricts the use of wind energy. In this sense, offshore semi-submersible platforms appear as an option, which in addition enables the integration of complementary elements, for instance wave energy converters. However, the complexity of the system increases due to the interactions between the platform movements and the wind turbine, and traditional control techniques do not enable to cope with these interactions in an easy way, hence limiting the efficiency of energy harvesting. Intelligent control techniques are an option with a great potential to take full account of the said interactions and to improve energy production efficiency. Still, it is required to have simulation models including those effects beforehand, so that the effects of a designed controller on the system can be evaluated. This paper presents an original fuzzy logic controller that tunes a reference controller, improving its performance according to a developed methodology that allows evaluation of controllers for wind turbines in semi-submersible platforms. The resulting fuzzy logic controller allows higher efficiency concerning mechanical loads in the system, electric energy production and tracking error of the speed reference. Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech.

The Royal Navy’s Type 45 Destroyers have been in Service since Jul 10 and have acquired a reputation for being a world class Air Defence asset with power and propulsion (P and P) fragility, that has attracted much positive and negative attention. This paper sets out how a range of circumstances combined in those early years to make the Class unique; a world leading ship not at her full potential. Many of the contributing factors have been discussed in isolation but have not been combined in one paper. The Type 45 has a modest class size of six vessels, yet each ship has the greatest capability ever installed in a Destroyer. It achieved such a punch due to the largest technology step taken in one class, 80% of the equipment on board is new to Royal Navy (RN) Service. And the ambition to use such a potent ship meant that HMS DARING deployed, worldwide, in the quickest time from build of any RN ship since WW2. Simultaneously and with huge dedication from the team, a new support solution was introduced that had the largest Industry involvement the MoD had ever contracted for a Complex Warship. These, and other circumstances created a heady mix in the early part of this decade and this paper will discuss the lessons learnt from an engineering support perspective. It will combine the experience of our predecessors with our own to give a unique perspective of the first nine years of the Class’s life. It will go on to show how improvements have been identified and embodied across the class ensuring that the Type 45 remains a world beating Air Defence Destroyer at her full potential for the next two decades.

The technologies of: Anthropometric Modelling, Game Engine animation and Virtual Reality were integrated to facilitate early design decisions in the design of future Naval weapon systems and their integration into current and future Naval platforms. CAD Models of existing or future ships were imported into a 3D Games engine (Unity) along with CAD Models from the ship architect/designer of specific compartments where weapon system installations were proposed. Extremes of the user population (e.g. 3rd percentile Navy female and 97th percentile Navy male) were modelled performing the installation / maintenance tasks on the equipment and this was then exported/imported into the 3D Unity environment and viewed from predefined eye height perspectives. Within the Unity 3D environment, realistic dynamic aspects of the real world were added – e.g. ship movement in light or heavy seas as well as consequent human head / body movement (compensating for ship movement) and the effects that this may have on the task. In addition weather and visibility effects can be added which may affect the user’s ability to perform the tasks. Design engineers viewing the model in VR were able to get a sense of the distances / gaps / access from within the 3D model itself and make/feedback design recommendations from the unique perspective of being immersed within the design itself.

В статье исследуется модель автономного подводного аппарата с 6 степенями свободы, для которого поставлена задача восстановления неизвестных входных данных для построения управления. Для решения этой задачи был построен асимптотический наблюдатель в боковой и поперечной плоскостях. Проведено численное исследование сходимости построенных оценок к актуальным данным, показано, что наблюдатель позволяет избавиться от неопределенности во входных данных., The article develops the design of asymptotic observer for a 6-DOF Autonomous Underwater Vehicle (AUV) to reconstruct of the unknown input for a control. Asymptotic observer is designed in lateral and vertical plane. Shown that the resulting estimation vector designed by asymptotic observer is able to reconstruct input data.

The development of precise and robust navigation strategies for Autonomous Underwater Vehicles (AUVs) is fundamental to reach the high level of performance required by complex underwater tasks, often including more than one AUV. One of the main factors affecting the accuracy of AUVs navigation systems is the algorithm used to estimate the vehicle motion, usually based on kinematic vehicle models and linear estimators. In this paper, the authors present a navigation strategy specifically designed for AUVs, based on the Unscented Kalman Filter (UKF). The algorithm proves to be effective if applied to this class of vehicles and allows to achieve a satisfying accuracy improvement compared to standard navigation algorithms. The proposed strategy has been experimentally validated in suitable sea tests performed near the Cala Minnola wreck (Levanzo, Aegadian Islands, Sicily, Italy). The vehicles involved are the Typhoon AUVs, developed and built by the Department of Industrial Engineering of the University of Florence during the THESAURUS Tuscany Region project and the European ARROWS project for exploration and surveillance of underwater archaeological sites. The proposed algorithm has been implemented online on the AUVs and tested. The validation of the proposed strategy provided accurate results in estimating the vehicle dynamic behavior, better than those obtained through standard navigation algorithms.

High power, high efficiency propulsion equipment with a high shock resilience capability that occupies the minimum volume, with a low weight and a very low noise signature is a “holy grail” of naval propulsion. Significant steps towards this goal have been made in the area of naval electric propulsion in the last 30 years, but it is hard to combine all these features in a single design since some features tend to militate against others. Solutions, therefore, require a balance between the thermal challenges of high power in a low volume and the requirement for shock proof, low signature machines. A permanent magnet propulsion motor with a patented novel cooling system designed for power density and low structureborne noise is being developed, manufactured and tested as a technology demonstrator. It is part of a programme part funded by InnovateUK under the Optimised Electric System Architecture project in partnership with the University of Nottingham and the University of Warwick. The primary market for the motor is envisaged to be naval and marine research vessels where power density and low noise is important. The motor is low speed and designed for direct mechanical coupling in the shaft line to the propeller and will be suitable for full electric or hybrid propulsion since the design is inherently scalable from relatively low powers up to those required for full electric warship propulsion. This paper describes the principles of the design and the approaches used to achieve the combination of high power density, high efficiency, high torque and low noise. It describes the thermal management approach and how the thermal behaviour of the different elements of the motor have been modelled. It also shows how advanced modelling techniques, combined with laboratory based and simple, practical testing have been used to develop the design and the manufacturing techniques required by this innovative solution. The paper also describes the testing approach used to validate the machine and its integration into a wider Direct Current or Alternating Current distribution system that could include energy storage elements. Finally, the performance of the motor is discussed along with the probable next stages in its development.&nbsp

The day to day challenges of maintaining legacy complex warships demands an ever increasing level of support to address the through life challenges of equipment obsolescence and an increasing number of emergent defects. To improve the materiel state of the in service platforms, a greater use of technology and data analytics is now being applied optimising the maintenance and through life support of key equipment and systems. This paper provides a case study of the Babcock Warship Technical Authority (WTA) contribution to an equipment availability review of the maintenance schedule of the Voith Schneider Propulsion (VSP) system for the Single Role Mine Hunter (SRMH) Sandown class. The paper reviews the trends from historical oil sampling and vibration monitoring data, in combination with operational defects. These trends were compared with the reliability centred maintenance tasks to optimise support. The FMECA methodology has been applied to this information to provide recommendations on (i) the amount of condition based monitoring being applied, (ii) revisions to the standard operating procedures, (iii) the logging of environmental conditions; and (iv) baselining of equipment performance. The paper also considers the work being undertaken to optimise the through life support of the equipment, covering logistics, documentation and training. The role of the WTA is to introduce innovation and deliver intelligence lead support solutions at the waterfront to enhance the crew’s ability to take ownership and maintain their platform efficiently. This case study provides an example of how data trending and analysis can optimise the maintenance routine for key equipment on legacy platforms.&nbsp

The German joint project GALILEOnautic aims to develop systems for autonomous navigation and optimised manoeuvring of vessels cooperating in areas with high safety and efficiency requirements, such as harbours or narrow waterways. In the conception of this project, the SAE levels of the automotive industry were applied for classification of intended levels in automation of already being used manoeuvring vessels. It fairly soon became apparent that the conditions in development of new autonomous road vehicles and the appropriate infrastructure are significantly different in comparison to adaption of navigation and manoeuvring of watercrafts which are part of a complex transport network. Therefor and in relation to the few orientating guidelines addressing autonomous maritime applications, a specific concept for manoeuvring automation in high safety areas was developed. It defines the automation levels towards autonomous shipping considering the current practice and the technical equipment on such vessels, the legal framework for automatic shipping as well as the requirements for integrating automatic manoeuvring in the traditional shipping traffic. The contribution introduces this automation concept and the necessary infrastructure for each level. Additionally, the results of the first project phase are presented. It implies the essential sensor equipment and subsequent data fusion to describe completely the dynamic ship motion and to recognise the close surrounding of the vessel. A hybrid control scheme is applied including feedforward and feedback modules. The control approach is illustrated by interfered encounter situations in ship handling simulator and for unmanned surface vehicles. The paper gives a prospect on the future investigations for higher manoeuvre automation.

The objective of this paper is to show the initial research results obtained with an automatic 3D design software tool we have developed for spool fitting in the pipe workshop of the Navantia Ferrol shipyard. This software tool requires, as input, a CAD file containing the scene with the two pipes to connect, and provides, as output, a CAD file with the fitted spool design. The software detects the features of the spool, and a heuristic pipe routing algorithm generates the output by computing several routes and providing one solution that is near to the optimal one. This output design considers the characteristics and capacities of the manufacturing process, as well as the library of materials used in the shipyard, so it is possible to use it for direct manufacturing. The preliminary results presented here were obtained using real data captured with different commercial 3D scanners over a test setup.

Crews of naval vessels lack an up-to-date awareness of those aspects of a ship’s susceptibility to threats that are related to the actual ship signatures (acoustic, magnetic, infrared, etc.). The ship’s susceptibility depends among others on the current configuration of the ship, the environment, the enemy sensor capabilities and the related ship signature levels. For operational purposes, it is desirable that crews have a tool which informs and advises them on the ship signatures, on ways of managing them and on the consequential detection ranges of adversary sensors in the current tactical situation. A functional demonstrator for such a support tool, called COSIMAR (Continuous Operational Signature Monitoring Awareness and Recommendation), has been developed and tested in a laboratory environment in an international project. The background and approach of this international cooperation between Canada, Germany, Norway, Belgium and The Netherlands had been presented at the INEC conference 2014 in Amsterdam. This year's presentation will show the result of this joint effort. The architecture, human machine interface, signature and susceptibility models will be addressed, including the laboratory environment simulating all required platform and environmental input.

Electro-Turbo-Compounding (ETC) is a system whereby energy contained in the hot gas of a diesel-engine exhaust is partially recovered through its conversion via a high-speed gas turbine driven alternator into electrical energy. ETC makes a diesel-engine system work more cleanly and effectively thereby improving power density and fuel efficiency. The technology is equally suited to new-build and retrofit applications. Applications to date have been extensive in the 150 kW – 2 MW range and the 10 MW – 20 MW but almost exclusive to shore-based power stations across the world. This paper reports on the progress of an Innovate UK funded project (2015-18) to develop ‘marinised’ units with partners UCL, Bowman Power Group Ltd., Lloyd’s Register and Rolls Royce PLC. With an expectation on the shipping industry (including naval ships) to reduce their carbon footprint the ETC is suitable for marine engineering application in those ships not easily able to use the conventional Rankine Cycle exhaust gas waste heat recovery system. The paper discussions include the design, modelling and practical testing approaches, results on performance for various arrangements for propulsion and electrical power, and importantly the integration challenge to ensure NOx Compliance and Certification. Within the paper discussion is also made about the financial aspects for propulsion and electric generation applications. The operating profile of different vessels gives different paybacks which are particularly favourable at times of rising fuel prices.

Oceanids is a 4-year programme for the technological development of innovative Maritime Autonomous System (MAS) platforms and associated sensors that will include next generation robotic AUVs, sensors and networks to undertake ambitious, long-range, long-endurance deployments in extreme and hazardous environments, such as the deep ocean or under-ice environments. This paper describes the design of two new types of robotic AUVs, the Autosub 2000 Under-Ice and the Autosub Long Range 1500 vehicles that are being developed under the programme. Two key components of the AUVs are described, the autonomy framework and the navigational system, which relies on a newly developed terrain-aided navigation (TAN) system. At-sea results of the TAN are also reported as obtained during long duration operational deployments done in 2017.

Many candidate power system architectures are being evaluated for the Navy’s next generation all-electric warship. One proposed power system concept involves the use of dual-wound generators to power both the Port and Starboard side buses using different 3-phase sets from the same machine (Doerry, 2015). This offers the benefit of improved efficiency through reduced engine light-loading and improved dispatch flexibility, but the approach couples the two busses through a common generator, making one bus vulnerable to faults and other dynamic events on the other bus. Thus, understanding the dynamics of cross-bus coupling is imperative to the successful implementation of a dual-wound generator system. In (Rashkin, 2017), a kilowatt-scale system was analysed that considered the use of a dual-wound permanent magnet machine, two passive rectifiers, and two DC buses with resistive loads. For this system, dc voltage variation on one bus was evaluated in the time domain as a function of load changes on the other bus. Therein, substantive cross-bus coupling was demonstrated in simulation and hardware experiments. The voltage disturbances were attributed to electromechanical (i.e. speed disturbances) as well as electromagnetic coupling mechanisms. In this work, a 25 MVA dual-wound generator was considered, and active rectifier models were implemented in Matlab both using average value modelling and switching (space vector modulation) simulation models. The frequency dynamics of the system between the load on one side and the dc voltage on the other side was studied. The coupling is depicted in the frequency domain as a transfer function with amplitude and phase and is shown to have distinct characteristics (i.e. frequency regimes) associated with physical coupling mechanisms such as electromechanical and electromagnetic coupling as well as response characteristics associated with control action by the active rectifiers. In addition, based on requirements outlined in draft Military Standard 1399-MVDC, an approach to derive specifications will be discussed and presented. This method will aid in quantifying the allowable coupling of energy from one bus to another in various frequency regimes as a function of other power system parameters. Finally, design and control strategies will be discussed to mitigate cross-bus coupling. The findings of this work will inform the design, control, and operation of future naval warship power systems.

While commercially available AUVs are routinely used in survey missions, a new set of applications exist which clearly demand intervention capabilities. The maintenance of permanent underwater observatories, submerged oil wells, cabled sensor networks, pipes and the deployment and recovery of benthic stations are a few of them. These tasks are addressed nowadays using manned submersibles or work-class ROVs, equipped with teleoperated arms under human supervision. Although researchers have recently opened the door to future I-AUVs, a long path is still necessary to achieve autonomous underwater interventions. This paper reviews the evolution timeline in autonomous underwater intervention systems. Milestone projects in the state of the art are reviewed, highlighting their principal contributions to the field. To the best of the authors' knowledge, only three vehicles have demonstrated some autonomous intervention capabilities so far: ALIVE, SAUVIM and GIRONA 500, being the last one the lightest one. In this paper GIRONA 500 I-AUV is presented and its software architecture discussed. Recent results in different scenarios are reported: (1) valve turning and connector plugging/unplugging while docked to a subsea panel, (2) free floating valve turning using learning by demonstration, and (3) multipurpose free-floating object recovery. The paper ends discussing the lessons learned so far This work was supported by the Spanish project DPI2011-27977-C03v (TRITON) and three European Commissions Seventh Framework Program 2011-2015 projects: FP7-ICT-2011-7- 288704 (MORPH) and FP7- INFRASTRUCTURES-2012-312762 (EUROFLEETS2)

In this paper problem of source-seeking and tracking underwater target by surface vehicle using range measurements with low sampling rate is addressed. Paper compares three extremum seeking schemes: classical extremum seeking, EKF based gradient estimation extremum seeking and EKF based gradient estimation extremum seeking enhanced with static function model data. It is shown that using additional model information can improve gradient estimation when dealing with intermittent range measurements.

This paper presents the development of an unmanned underwater vehicle (UUV) platform, especially the derivation of the vehicle&rsquo, s simulation model and its control method to overcome strong sea current. The platform is designed to have a flattened ellipsoidal exterior so as to minimize the hydrodynamic damping on the horizontal plane. Four horizontal thrusters with the identical specifications are symmetrically mounted on the horizontal plane, and each of them has the same thrust dynamics in both forward and reverse directions. In addition, there are three vertical thrusters used to handle the vehicle&rsquo, s roll, pitch and heave motions. Control strategy proposed in this paper to overcome strong current is that: maximizing the vectored horizontal thrust force against the sea current without or with the least of the vehicle&rsquo, s rotation on the horizontal plane. For the vehicle model, due to it being symmetric in all of three axes, the vehicle dynamics can be simplified and all of hydrodynamic coefficients are calculated through both of theoretical and empirically-derived formulas. Numerical simulations and experimental studies in both of the water tank and the circulating water channel are carried out to demonstrate the vehicle&rsquo, s capability of overcoming strong current.

RW collected the BC data with Raincoast Conservation Foundation, and was supported by a Marie Curie International Incoming Fellowship within the 7th European Community Framework Programme (proposal no. 253407 (call reference: FP7‐PEOPLE‐2009‐IIF)) during the analysis stage. Despite lessons from terrestrial systems, conservation efforts in marine systems continue to focus on identifying priority sites for protection based on high species richness inferred from range maps. Range maps oversimplify spatial variability in animal distributions by assuming uniform distribution within range and de facto giving equal weight to critical and marginal habitats. We used Marxan ver. 2.43 to compare species richness-based systematic reserve network solutions using information about marine mammal range and relative abundance. At a global scale, reserve network solutions were strongly sensitive to model inputs and assumptions. Solutions based on different input data overlapped by a third at most, with agreement as low as 10% in some cases. At a regional scale, species richness was inversely related to density, such that species richness hotspots excluded highest-density areas for all species. Based on these findings, we caution that species-richness estimates derived from range maps and used as input in conservation planning exercises may inadvertently lead to protection of largely marginal habitat. Publisher PDF

Recent studies relative to range-only localization in underwater robotics applications have focused primarily on (nonlinear) observability analysis. In particular, local weak observability is guaranteed as long as the motion of the system to be localized is sufficiently rich, i.e. persistency of excitation conditions need to be satisfied. These conditions typically depend on the initial state of the system and on its inputs. Once that the challenging problem of identifying the necessary initial state and input constraints for guaranteeing local weak observability has been solved, state estimation can be performed resorting to linear (Kalman-like) filters. Yet the convergence of such state estimation approaches is local. Building on recent results in this area, this paper addresses the problem of designing input signals for a class of underactuated underwater vehicles allowing global range-only pose estimation.

As marine robotics becomes more and more effective and useful for many real applications, control techniques too must be gradually enhanced in order to answer to the arising need of full autonomy for such vehicles. Hence more advanced control algorithms are currently under-development in the marine robotics community in order to accomplish many tasks with more robustness and reliability. In particular, the present work addresses the path following problem, applying the control paradigm of prioritized tasks, usually exploited for robotic manipulators. Such a technique, besides allowing to keep separate the different tasks, thus getting an “emergent behavior” for the vehicle, also provides the ability to easily add further control tasks without changing the architecture. In the present paper the case of two simple tasks allowing the completion of a path following mission, as well as the vehicle velocity regulation, is dealt with and some simulative results are described.

[EN] Automatic control is an horizontal subject and many of their branches are applied in the marine fields: robotics, control engineering, artificial intelligence, modeling and simulation, sensors and actuators. The paper presents an overview of some of the major advances that have taken place from the point of view of marine vehicles modeling, identification and control., [ES] La Automática es una disciplina horizontal muchos de cuyos temas se aplican en el campo del sector marítimo, como son: la robótica, la ingeniería de control, la inteligencia artificial, el modelado y la simulación, los sensores y los actuadores. En este trabajo hacemos una revisión de los avances que han tenido lugar en los últimos años desde el punto de vista del modelado, la identificación y el control de los vehículos marinos., Este trabajo ha sido desarrollado gracias al apoyo de la Secretaría de Estado de Investigación, Desarrollo e Innovación mediante los proyectos coordinados DPI2009-14552-C02-01 y DPI2009-14552-C02-02.

The problems of implementing special control functionality for trailing suction dredgers in dynamic positioning (DP) systems are considered, focusing mainly on the dredging track control modes. The motion controller is proposed which provides the trajectory steering with the draghead under restrictions, imposed by the dredging process and equipment (sufficiently large velocities, drift angle limitations etc.) Algorithms of drag head position measurements and drag pulling force estimation are discussed. The results of sea trials of a DP system operating on real large hopper trailing suction dredger are presented.

By the thrust ability diagram of the dynamic positioning vessel we mean the set of all 3-dimensional vectors ( F X , F Y , M Z ) constituted by surge and sway forces and the rotating yaw moment that can be provided by the set of vessel's actuators. We consider algorithms for approximation (with arbitrary accuracy) of the thrust ability diagrams with a union of convex polytopes and estimate the computational complexity of these algorithms.

This paper proceeds to lay out the activities being performed by the Croatian group of researchers from University of Zagreb, Faculty of Electrical Engineering and Computing, Department of Control and Computer Engineering, Laboratory for Underwater Systems and Technologies (LABUST), after having successfully applied to the REGPOT-2008-1 call and having been awarded a capacity-building grant for the “Developing the Croatian Underwater Robotics Research Potential – CURE” project. The scientific contributions to the state of the art of underwater and marine system technology of LABUST, based on which the capacity to further and intensify research activity is being built within the CURE project, fall mainly into three categories: (1) unmanned small vessel modeling and identification, cf. Miskovic et al. (2009a,b,c). (2) distributed coordinated and cooperative control, cf. Barisic at al. (2008, 2009a,c). (3) embedded control systems engineering and software design, cf. Barisic et al. (2009b,d).

This work uses empirical data from the HELCOM database and a new empirically-based model to predict the concentration of cyanobacteria in the Baltic Proper. The aim has been to estimate nitrogen fixation. The inherent variabilities/patchiness in the variables regulating nitrogen fixation are great. This means that different approaches may provide complementary information so that several relatively uncertain estimates may together provide less uncertainty in the estimate for nitrogen fixation in a given system. We show that there is marked variability in nitrogen fixation among different years (a factor of 20 between the year 2001 with the smallest value and 2005 with the highest value of about 900 kt/yr of N-fixation). The mean value for the period from 1997 to 2005 was 190 kt/yr. TN/TP based on median monthly data has been higher than the Redfield ratio of 7.2 since 1994. 6.5% of all individual data (n = 3001) from the surface-water layer (44 m) in the Baltic Proper for samples with temperatures higher than 15°C (when risks of getting cyanobacteria blooms are favoured) have TN/TP lower than 7.2. The mean TN/TP is 20 for surface-water sites with temperatures higher than 15°C, indicating that the average trophic conditions in the Baltic Proper are likely more limited by phosphorus than nitrogen. Nitrogen fixation is an important contributor to the nitrogen concentration and we give overall budgets for nitrogen and phosphorus in the Baltic Proper, including nutrient data from land uplift, which is the most important contributor for nutrients and often neglected in discussions about sources of nutrients to the Baltic Sea. Thresholds, 6th framework, EU

This paper demonstrates the use of self-oscillation identification experiments for tuning heading and line following controllers for marine vehicles. The identification by use of self-oscillations (IS-O) has been developed for general LTI systems and for a class of nonlinear systems and it was used for tuning guidance controllers. The guidance controllers have been tuned using the results from IS-O experiments. Heading controller algorithm that gives smooth control output is presented. The line following controller generates reference heading as output. The described methodology is applied to autonomous catamaran Charlie and the experimental results are presented in the paper. It has been demonstrated that IS-O method gives good results in field conditions and that it is time conservative. All algorithms and results presented here are a result of joint work of researchers at the Consiglio Nazionale delle Ricerche, Genova and the University of Zagreb.

A novel controller for cranes employed in heavy-lift offshore marine operations is proposed. The control objective is to reduce the hydrodynamic slamming load acting on a product at water-entry of moonpool operations; at the same time the values of the wire tension must be kept within acceptable bounds. The control design is based on an extension of classical SISO feedback design to the case of not measurable controlled output. The effectiveness of the proposed design is shown experimentally. The experiments are carried out using a scale-model of a crane vessel with a moonpool. Experimental results show improvements with respect to a previous feedforward controller.

Underwater environment is characterized by harsh conditions and is difficult to monitor. The CADDY project deals with the development of a companion robot devoted to support and to monitor human operations and activities during the dive. In this scenario the communication and correct reception of messages between the diver and the robot are essential for success of the dive goals. However, the underwater environment poses a set of technical constraints hardly limiting the communication possibilities. For such reasons the solution proposed is to develop a communication language based on the consolidated and standardized diver gestures, commonly employed during professional and recreational dives, thus leading to the definition of a CADDY language, called CADDIAN, and a communication protocol. This article focuses on the creation of the language providing alphabet, syntax and semantics: future work will explain the part of recognition of gestures that is still in progress.

Most cooperative motion tasks of multi vehicle systems require the agents to share relative localization information. Assuming the relative velocity of the vehicles to be known, under suitable observability conditions, relative localization among a pair of agents can be performed based on single range measurements. The problem addressed consists in designing a relative localization solution for a networked group of vehicles measuring mutual ranges: in particular, the objective is to exploit the presence of intra-vehicle communications to enhance the range-based relative position estimation. Geometrical constraints associated to the agents' (unknown) positions are explicitly accounted for in the estimation schema. The approach brings together a recent single range localization solution with a projection based Kalman filter estimation technique in the presence of state space constraints. Simulation examples are provided showing the effectiveness of the proposed solution.

Diving as a profession and sport is and will be one of the most dangerous disciplines known by man. Water is not a natural habitat for humans and people need equipment to breathe underwater. Failure in the breathing apparatus, burst eardrum, decompression sickness and nitrogen narcosis are just a couple of problems which can occur during an ordinary dive and result in injuries, long-term illnesses or even death. The most common way to reduce the risk of diving is to dive in pairs. Use of the buddy system by scuba divers is a set of safety procedures that are intended to improve divers’ chances of avoiding or surviving accidents underwater. When diving in pairs, divers can cooperate with each other and respond when uncommon situations occur. Having the ability to react before an unwanted situation happens would improve diver safety. This paper proposes a mechanical system which will be used with a scuba diver in a symbiotic link. The concept consists of a diver, an autonomous underwater robot (Buddy) and an autonomous surface robot (PlaDyPos).

[ES] Las corrientes marinas, fuente de energía renovable más predecible, localizan la mayor parte de su energía en altas profundidades. Para aprovechar esta energía se están desarrollando dispositivos flotantes, de tipo fondeado. La viabilidad económica de estos dispositivos requiere el abaratamiento de costos. El desarrollo de sistemas de control que permitan el cambio automático de orientación y profundidad del generador, con el fin de abaratar las maniobras de mantenimiento y aprovechar el recurso energético de forma óptima, resulta imprescindible. En este trabajo se presenta un actuador hidrostático y se realiza un modelo dinámico simple para control, de un dispositivo de dos grados de libertad, con un sistema de control de lastre. A partir de este modelo se ha desarrollado una ley de control multivariable, basada en una matriz de desacoplamiento no lineal y en la compensación de los términos de fricción y compresibilidad. Finalmente, la bondad del controlador ha sido validada mediante simulación., [EN] Marine currents represent the most predictable source of renewable energy. The greatest percentage of its energy is located in areas with high depths. In order to be able to operate at these depths, new devices are being developed, floating anchoring type. The economically viable harnessing of the tidal energy with these devices requires the development of control systems. These systems must allow the automatic change of orientation and depth of the generator to harness the energy in an optimal way. In this paper, a type of hydrostatic actuator based on the controlled handling of water ballast is selected. Next, a dynamic model, provided with two degrees of freedom, is presented for the control of a submerged device for the exploitation of tidal currents. From this model, a multivariate control law has been developed, based on a non-linear decoupling matrix and on the compensation of the terms of friction and compressibility. Finally, the controller's goodness has been validated by the development of several simulations., Este trabajo se ha realizado con financiación parcial del Mº de Ciencia e Innovación, a través del Proyecto de Investigación. Fundamental DPI2014-53499-R CoDMAEC.

The increasing scientific and economic interest in the visual exploration and monitoring of marine areas is creating huge amounts of new underwater image and video data and approaches to computationally assisted analysis are desperately needed. In this paper we propose an image patch feature representation concept, the Bag of Prototypes (BoP), to cope with the individual problems in underwater image analysis. We consider the case of seafloor classification, which is relevant in many contexts such as habitat mapping or the exploration of mineral resources and show, that the BoP concept allows an efficient and accurate tile-wise estimation of poly-metallic nodule coverage in relation to two differently acquired gold standards.

Nitrogen (N) is applied worldwide to produce food. It is in the atmosphere, soil, and water and is essential to all life. N for agriculture includes fertilizer, biologically fixed, manure, recycled crop residue, and soil-mineralized N. Presently, fertilizer N is a major source of N, and animal manure N is inefficiently used. Potential environmental impacts of N excreted by humans are increasing rapidly with increasing world populations. Where needed, N must be efficiently used because N can be transported immense distances and transformed into soluble and/or gaseous forms that pollute water resources and cause greenhouse effects. Unfortunately, increased amounts of gaseous N enter the environment as N2O to cause greenhouse warming and as NH3to shift ecological balances of natural ecosystems. Large amounts of N are displaced with eroding sediments in surface waters. Soluble N in runoff or leachate water enters streams, rivers, and groundwater. High-nitrate drinking water can cause methemoglobinemia, while nitrosamines are associated with various human cancers. We describe the benefits, but also how N in the wrong form or place results in harmful effects on humans and animals, as well as to ecological and environmental systems.

This paper describes a combined helm-sails controller for a sailboat based on fuzzy logic. Autonomous navigation of sailboats is a very nonlinear and time-variant problem, and modeling ship dynamics considering all real phenomena is a very complex task. Besides, it has to compensate for stochastic disturbances acting upon it, such as wind, waves, and currents. Heuristics in sailing plays an important role: sailing rules obtained from skippers can be included in a knowledge base to govern the boat correctly in different conditions. The controller measures variables such as heading and wind angle. It processes the data through a fuzzy inference system according to a sailing knowledge base and actuates the helm and the sails. Experiments with a scale prototype show the ability of a fuzzy controller to govern the helm and trim the sails on a sailboat. Sea navigation aid systems and autonomous ocean sampling vehicles could be some areas of application of such a fuzzy system.

In this paper we describe our experience in porting a real-world legacy application, namely the statistic evaluation of ship vulnerability, to a parallel execution environment dynamically distributed over the intra-net Of the Italian naval research center (CETENA). More in details, we describe how we leveraged the dynamic, plug-in based metacomputing infrastructure provided by the HARNESS system to reconcile the requirements of a legacy application tightly tied to a specific CAD environment with a grid-like metacomputing environment in order to deploy over the machines connected through an intra-net multiple instances of the application, coordinate their execution, collect the so produced results and merge them into a unified, statistically improved simulation.

This paper deals with the detection of the rescue target as a particular object from motion images under bad weather conditions. When shipwrecks occur, the searching activities for rescue is done using an airplane. The detection of the rescue target such as life rafts depends on a visual search by human eyes. To detect a small rescue target in a wide sea area, the searching man must monitor motion sights under nasty weather. The human eyes sometimes loses its sight and the ability of detection fails owing to the long flight and the nasty weather. To support the searching activities in the case of a marine casualty, we propose motion image processing techniques using the improved S/N ratio and dynamic range of the image data of the rescue target in the motion images under bad conditions

The emergence of huge container ships together with the scarcity of yard land put an enormous pressure on authorities to adopt advanced technologies to increase the throughput of current container terminals. Automated Container Terminals (ACT), using advanced material handling technologies, are recently considered as candidates for increasing the performance of manually operated yards. In this paper, an ACT that employs Linear Motor Technology is designed. A multi attribute decision making method is employed to find the optimum number of conveyor shuttles in the terminal. Simulations demonstrate a double increase in the throughput of ACT compared to the similar one with manual operations. © 2001 EUCA. 289 294 Sponsors: Directorate General XII of the European Commission Faculdade de Engenharia da Universidade do Porto Conference code: 112066

At one time, few people lived permanently near the edges of the world’s oceans. Now, more than half of the world’s population lives near beaches and estuaries. People in developed countries have primary or secondary homes there to enjoy the views and for recreation. Poor people in developing countries live there to engage in fishing, jobs in tourism for people from developed countries, and for subsistence farming in river delta areas. They remain despite persistent hurricanes, typhoons, and resulting flooding. There is a serious disconnect for both rich and poor people between the reality of living near oceans and the danger that this entails. For a variety of reasons, people are becoming less and less connected to the world around them. Natural events that have devastating effects on humans are considered to be strange and unusual, rather than a normal part of human existence on a continually changing planet. Our disconnect from nature has serious consequences. Earthquakes under the oceans, from shifting tectonic plates or volcanic eruptions, are known to result in oceanic disturbances that result in elevated wave activity near ocean shores. A high wall of water, or wave, that emerges from the water column caused by an ocean disturbance is called a tsunami (Japanese for “harbor wave”). Globally, 80% of tsunamis occur in the Pacific Ocean region. Seismic waves above 7.5 m occur there naturally every 15 years. Tsunamis are not unusual events. When I was in Japan recently, I discovered that they are a favorite theme in Japanese art, especially in woodblock prints. The earthquake that recently occurred in the Indian Ocean was unusually strong (9.0 on the Richter Scale) and the resulting tsunami resulted in horrific loss of life and property in countries like Indonesia, India, and Sri Lanka. Television has enabled everyone to witness the devastation and its aftermath. More than 150,000 people have died and huge coastal areas have been destroyed. Stunned local populations are responding to an enormous outpouring of international relief aid. What will be the aftermath of this devastating tsunami? Reefs have been damaged or destroyed as have coastal mangrove areas and estuaries. What effects this will have on fish populations and reproduction are unknown. Ponds used to cultivate shrimp have been destroyed. Few fishing boats are left to harvest what fish may be left. Seawater was driven inland, killing plants and animals, and infiltrating agricultural land and wells used for drinking water. The long-term effects on agriculture and well water are not known. Ecologists have an opportunity to study recolonization of affected areas by plants and animals. Epidemics of diseases have not developed as prompt burial of bodies and distribution of clean water and