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Coastal areas currently face a lot of anthropogenic pressures (Erlandsson et al, 2011; Wilcox et al, 2020) which might further increase through climate change (Maltby et al, 2022). This can lead to the disappearance of crucial, habitat engineering species like blue mussels (Tummon Flynn et al, 2020). The lack of those increases the risk of eutrophication and pollution, on the long run having negative consequences not only for biodiversity and ecological factors but also social and economic factors like income through fishing and risking coastal flood protection (Tummon Flynn et al, 2020; Schotanus et al, 2020; Cooley & Doney, 2009). Blue mussels can form biogenic reefs, which are protected as important habitats under the EU Habitats Directive (Council of the European Communities, 1992) as well as the EU Water Framework Directive (European Parliament & council, 2000). Nevertheless, actual implementation of protection and conservation of those reefs is lacking (Rees et al, 2018), which is why many of them are declining drastically (EEA, 2013). One reason for that lack of protection might be the diverse definitions applied to mussel reefs all over Europe (Stounberg, 2021), while another one could be that many of them are not mapped. In the present study, an attempt was made to map a potential blue mussel reef in the Roskilde Fjord in Denmark, which was first discovered by a previous study (Dahl et al, 2019:39) but not investigated to its extend as that study focused on other goals. A ROV was employed to collect video data of the seafloor of the respective fjord area over a period of three months. The recorded video and GPS data was then processed and analysed to produce a map in QGIS, showing if and where an area of, according to the Danish definition for blue mussel reefs, more than 2500m2 with more than 30% mussel cover and 3 year classes of mussels (Miljøstyrelsen, 2018), is present. Three areas in the chosen search area of this study were confirmed to fulfil those requirements, consistent with the previous findings of Dahl et al (2019). The actual blue mussel reef might be even bigger as other areas which have not been analysed in detail contain blue mussels as well. Therefore, protection measures based on best available scientific knowledge, interdisciplinary work and the knowledge of as many stakeholders possible, including social, economic and ecological aspects, should be developed for the blue mussel reef in Roskilde Fjord. One of them could be to make the reef part of the Natura 2000 protection area already existing in the same area.

With the rising popularity of ROVs and other UV solutions, more robust and high performance controllers have become a necessity. A model of the ROV or UV can be a valuable tool during control synthesis. The main objective of this thesis was to use a model in design and development of controllers for an ROV. In this thesis, an ROV from Blue Robotics was used. The ROV was equipped with 6 thrusters placed such that the ROV was capable of moving in 6-DOFs. The ROV was further equipped with an IMU, two pressure sensors and a magnetometer. The ROV platform was further developed with EKF-based sensor fusion, a control system and manual control capabilities. To model the ROV, the framework of Fossen (2011) was used. The model was estimated using two different methods, the prediction-error method and an EKF-based method. Using the prediction-error method, it was found that the initial states of the quaternions had a large impact on the estimated parameters and the overall fit to validation data. A Kalman smoother was used to estimate the initial states. To circumvent the problems with the initial quaternions, an \abbrEKF was implemented to estimate the model parameters. The EKF estimator was less sensitive to deviations in the initial states and produced a better result than the prediction-error method. The resulting model was compared to validation data and described the angular velocities well with around 70 % fit. The estimated model was used to implement feedback linearisation which was used in conjunction with an attitude controller and an angular velocity controller. Furthermore, a depth controller was developed and tuned without the use of the model. Performance of the controllers was tested both in real tests and simulations. The angular velocity controller using feedback linearisation achieved good reference tracking. However, the attitude controller could not stabilise the system while using feedback linearisation. Both controllers' performance could be improved further by tuning the controllers' parameters during tests. The fact that the feedback linearisation made the ROV unstable, indicates that the attitude model is not good enough for use in feedback linearisation. To achieve stability, the magnitude of the parameters in the feedback linearisation were scaled down. The assumption that the ROV's center of rotation coincides with the placement of the ROV's center of gravity was presented as a possible source of error. In conclusion, good performance was achieved using the angular velocity controller. The ROV was easier to control with the angular velocity controller engaged compared to controlling it in open loop. More work is needed with the model to get acceptable performance from the attitude controller. Experiments to estimate the center of rotation and the center of gravity of the ROV may be helpful when further improving the model.

This research investigates the impact a Remotely Operated Vehicle (ROV) program has on student interest in, and perception of, technology and engineering (sTEm). ROV programs embed areas of science, technology, engineering and math (STEM) into their curriculum; however, emphasis for this study is placed on interest and perception of the "T" and "E" of STEM. Although there are many articles detailing the benefits of ROV programs, there is little empirical data documenting the impact on student interest and perception of sTEm. This study outlines the background of a few major ROV programs in the U.S.; specifically Utah Underwater Robotics (UUR), an ROV statewide program within a landlocked state, the methods for gathering data and findings from a sTEm survey instrument administered to over 300 students ranging from 6th to 12th grade who participated in a five-month ROV program and near 50 students who did not. Key findings include: 1. Males were more interested in technology and engineering than females, regardless of whether they participated in the UUR ROV program. 2. Male and female students in the UUR program were more interested and had a more positive perception of engineering than those who did not participate in the UUR ROV program. 3. Females in the UUR program reported more interest in engineering careers and activities than females not in the program. 4. Females in the program reported more interest and self-efficacy in science than females not in the program. 5. Males in the UUR program reported more awareness of the positive and negative consequences of technology and engineering than those who did not participate.

Remotely Operated Vehicles (ROVs) provide access to underwater environments too deep and dangerous for commercial divers. A tether connects the ROV to a vessel on the surface, providing power and communication channels. During extended manoeuvres, hydrodynamic forces on the tether produce large tensions which hinder ROV manoeuvrability. The research presented in this thesis focuses on the design of new tether management strategies that alleviate the tether disturbance problem, and the implementation of a navigation suite for tracking the ROV position and velocity which are needed to close the loop on the tether management method. To improve the estimation of the ROV state, an Extended Kalman Filter (EKF) is developed.

Current submerged science projects such as VENUS and NEPTUNE have revealed the need for small, low-cost and easily deployed underwater remotely operated vehiclemanipulator (ROVM) systems. Unfortunately, existing small remotely operated underwater vehicles (ROV) are not equipped to complete the complex and interactive submerged tasks required for these projects. Therefore, this thesis is aimed at adapting a popular small ROV into a ROVM that is capable of low-cost and time-efficient underwater manipulation. To realize this objective, the coordinated control of ROVM systems is required, which, in the context of this research, is defined as the collection of hardware and software that provides advanced functionalities to small ROVM systems. In light of this, the primary focus of this dissertation is to propose various technical building blocks that ultimately lead to the realization of such a coordinated control system for small ROVMs. To develop such a coordinated control of ROVM systems, it is proposed that ROV and manipulator motion be coordinated optimally and intelligently. With coordination, the system becomes redundant: there are more degrees of freedom (DOF) than required. Hence, the extra DOFs can be used to achieve secondary objectives in addition to the primary end-effector following task with a redundancy resolution scheme. This eliminates the standard practice of holding the ROV stationary during a task and uncovers significant potential in the small ROVM platform. In the proposed scheme, the ROV and manipulator motion is first coordinated such that singular configurations of the manipulator are avoided, and hence dexterous manipulation is ensured. This is done by using the ROV's mobility in an optimal, coordinated manner. Later, to accommodate a more comprehensive set of secondary objectives, a fuzzy based approach is proposed. The method considers the human pilot as the main operator and the fuzzy machine as an artificial assistant pilot that dynamically prioritizes the secondary objectives and then determines the optimal motion. Several model-based control methodologies are proposed for small ROV/ROVM systems to realize the desired motion produced by the redundancy resolution, including an adaptive sliding-mode control, an upper bound adaptive sliding-mode control with adaptive PID layer, and an H∞ sliding-mode control. For the unified system (redundancy resolution and controller), a new human-machine interface (HMI) is designed that can facilitate the coordinated control of ROVM systems. This HMI involves a 6-DOF parallel joystick, and a 3-D visual display and a graphical user interface (GUI) that enables a human pilot to smoothly interact with the ROVM systems. Hardware-in-theloop simulations are carried out to evaluate the performance of the coordination schemes. On the thrust allocation side, a novel fault-tolerant thrust allocation scheme is proposed to distribute forces and moments commanded by the controller over the thrusters. The method utilizes the redundancy in the thruster layout of ROVM systems. The proposed scheme minimizes the largest component of the thrust vector instead of the two-norm, and hence provides better manoeuvrability. In the first phase of implementation, a small inspection-class ROV, a Saab-Seaeye Falcon™ ROV, is adopted. To improve the navigation, a navigation skid is designed that contains a Doppler Velocity Log, a compass, an inertial measurement unit, and acoustic position data. The sensor data is blended using an Extended Kalman Filter. The developed ROV system uses the upper bound adaptive sliding-mode control with adaptive PID layer. The theoretical and practical results illustrate that the proposed tools can transform, a small, low-cost ROVM system into a highly capable, time-efficient system that can complete complex subsea tasks. / Graduate

The work presented in the thesis concerns the design and development of a novel thruster fault diagnosis and accommodation system (PDAS) for overactuated, open-frame underwater vehicles. The remotely operated vehicles (ROVs) considered in this thesis have four thrusters for motion in the horizontal plane with three controllable degrees of freedom (DoF). Due to the redundancy resulting from this configuration, for the case of a partial fault or a total fault in a single thruster it is possible to reallocate control among operable thrusters in order that the ROV pilot is able to maintain control of the faulty ROV and to continue with missions. The proposed PDAS consists of two subsystems: a fault diagnosis subsystem (FDS) and a fault accommodation subsystem (FAS). The FDS uses fault detector units to monitor thruster states. Robust and reliable interrogation of thruster states, and subsequent identification of faults, is accomplished using methods based on the integration of selforganising maps and fuzzy logic clustering. The FAS uses information provided by the FDS to perform an appropriate redistribution of thruster demands in order to accommodate faults. The FAS uses a hybrid approach for control allocation, which integrates the pseudoinverse method and the fixed-point iterations method. A control energy cost function is used as the optimisation criteria. In fault-free and faulty cases the FAS finds the optimal solution, which minimises this criteria. The concept of feasible region is developed in order to visualise thruster velocity saturation bounds. The PDAS provides a dynamic update of saturation bounds using a complex three-dimensional visualisation of the feasible region (attainable command set), such that the ROV pilot is informed with the effects of thruster fault accommodation, incorporated in the new shape of the attainable command set. In this way the ROV pilot can easy adapt to newly created changes and continue the mission in the presence of a fault. The prototype of the PDAS was developed in the MATLAB environment as a Simulink model, which includes a nonlinear model of an ROV with 6 DOF, propulsion system and a hand control unit. The hand control unit was simulated in hardware using a joystick as input device to generate command signals. Different fault conditions are simulated in order to investigate the performance of the PDAS. A virtual underwater world was developed, which enabled tuning, testing and evaluation of the PDAS using simulations of two underwater vehicles (FALCON, Seaeye Marine Ltd. and URIS, University of Girona) in a 'realistic' underwater environment. The performance of the PDAS was demonstrated and evaluated via tank trials of the FALCON ROV in QinetiQ Ocean Basin Tank at Haslar, where the existing control software was enhanced with the PDAS algorithm. The results of real-world experiments confirmed the effectiveness of the PDAS in maintaining vehicle manoeuvrability and in preserving the vehicle mission in the presence of thruster faults.

The subject of the diploma thesis is to design a new building of sports facilities at the documentation for building construction. The design emphasizes the layout, including the provision of structures for the static, architectural, fire safety, energy savings and safety while using the object. The work contains text and graphic part. The graphic part is processed in the ArchiCad.

<p dir="ltr">The technological advancements in marine robotics led to the expansion of the autonomous underwater vehicle (AUV) fleet. Depending on the applications, the type of the AUV ranges across various shapes and sizes. It seeks a solution for the issue of limited power capacity, often in terms of underwater docking systems. Underwater docking poses a significant challenge for AUVs, especially when considering the diverse shapes and sizes of these vehicles. Existing solutions usually are task specific, and do not address the idea of scalable underwater docking system design.<br>This thesis investigates the adaptability of the specific docking system design, previously validated for torpedo-shaped AUVs, to boxed-shaped AUVs in a nonlinear open water environment. In order to achieve this goal, the scalability of the docking system design of choice was tested in an open water non-linear underwater environment and validated. The scalability of the robust docking system was adapted to the box-shaped AUV, encompassing path planning, path following, and docking maneuver. The adapted docking system was based on the optic methods for docking station detection and subsequent docking. Additionally, the simulated environment was developed for the AUV model, for testing and debugging purposes. In the simulation, a custom PID controller was developed along with integrating the navigation and guidance package, to fully simulate the real life behavior of the AUV. </p><p dir="ltr">Furthermore, this work introduces a recurrent neural network-based architecture for investigating temporal dependencies of the sequential data input. The proposed architecture is based on CNN for spatial feature extraction and LSTM/GRU for temporal feature detection. The dataset collection is based on the simulation environment, by enhancing the artificial images with imposed realism. The dataset was gathered on different levels of turbidity and the collection process was automated.</p>

[pt] Nas últimas décadas, a crescente conscientização ambiental levou ao reconhecimento da necessidade do uso responsável dos recursos hídricos. Para garantir isso, a boa gestão de reservatórios hídricos requer um monitoramento ambiental adequado, com medições confiáveis dos parâmetros de qualidade da água em vários pontos do reservatório, permitindo o controle da qualidade da água e seus impactos na fauna, flora e comunidades ribeirinhas dos reservatórios. O monitoramento das variáveis ambientais dos reservatórios é atualmente realizado por processo tradicional de coleta manual. Infelizmente, no Brasil, as iniciativas de produzir um sistema robótico aquático com tecnologia nacional e de baixo custo, quando comparado a equivalentes importados, são ainda raras e se restringem a algumas poucas instituições acadêmicas, não tendo sido localizado nenhum fabricante comercial deste tipo de veículo no país. Visando preencher esta lacuna, o presente trabalho teve como objetivo o desenvolvimento do protótipo de um sistema robótico aquático capaz de se locomover autonomamente em lagoas, lagos e reservatórios, coletando informações físico-químicas da água e armazenando estes dados na memória. Além disso, foi incluído no protótipo uma câmera de vídeo, sistema de iluminação e um sistema de controle remoto, objetivando o controle pela equipe em terra. Nos testes realizados em dias ensolarados e chuvosos, o robô apresentou boa dirigibilidade, estabilidade e manobrabilidade. O vaso de pressão do sistema robótico resistiu às pressões necessárias durante os testes, a eletrônica conseguiu atender as especificações de projeto e o software conseguiu estabelecer um controle de navegação, cumprindo o trajeto de uma rota estabelecida. / [en] In recent decades, the growing environmental awareness has led to the recognition of the need for responsible use of water resources. To ensure this, the good management of water reservoirs requires adequate environmental monitoring, with reliable measurements of water quality parameters in various parts of the reservoir, allowing the control of water quality and its impacts on fauna, flora and riverine communities of the reservoirs. Monitoring environmental variables of the reservoirs is currently performed by traditional process of manual collection. Unfortunately, in Brazil, initiatives to produce a water robotic system with national and low cost technology, compared to imported equivalents, are still rare and restricted to a few academic institutions, and no commercial manufacturer of this type of vehicle was found in the country. Aiming to fill this gap, the main objective of this study was to develop a prototype of a water robotic system capable of autonomously navigate in ponds, lakes and reservoirs, collecting physicochemical information of water and storing this data in memory. Moreover, a video camera, illumination and a remote control system were included in the prototype, allowing the team on the ground to control the prototype. In tests conducted in sunny and rainy days, the robot presented good handling, stability and maneuverability. The robotic system pressure vessel resisted pressures required during testing, the electronics met the design specifications and the software was able to establish a navigation control, fulfilling the path of an established route.