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The aim of this article is to design, precisely and fully detailed, the Control Room of a Ballast Actuation System of a marine Tidal Energy Converter. The design would respond to the detail design stage of any shipyard for its subsequent manufacture. During the following lines, the authors have analysed the Ballast Actuation System, not only from a conceptual way, but also from the detailed design point of view, so it has been considered necessary to complete it, with a study of a technological nature, in which industrial (reducing the cost and increasing reliability) solutions have been developed for measuring and driving systems. To elaborate the 3D detail design of the pump room, a topological design has been introduced for allowing a quicker evaluation of different design alternatives. All the machinery, piping, supports and auxiliary structures have been modelled in order to evaluate the quality of the conceptual and initial design. The primary structure, as well as the location of the equipment, have been carefully studied and analysed. The P&ID (Piping and Instrumentation Diagrams) and access drawings have been followed in order to model the 3D pipe routing, supports and auxiliary structure. The 3D components have been defined from its main features (element ID, supplier, description, weight and centre of gravity) and its geometry (library or geometric macro model), provided by the supplier. All this work has been carried out with the intention of not only assess different alternatives, but also to generate at any time the information for manufacturing and mounting.

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.

Resumen: El objetivo principal de este artículo es presentar los métodos más habituales de aprovechamiento de distintos tipos de energías renovables procedentes del mar y analizar los modelos energéticos de los dispositivos utilizados para su explotación. Estos modelos son necesarios para el diseño del dispositivo así como para el estudio de su comportamiento dinámico. Su conocimiento resulta imprescindible también para su simulación dinámica y para el diseño de los algoritmos de control necesarios para conseguir una optimización energética y económica. En este trabajo se presentan algunos de los diferentes tipos de energías del mar, y se j ustifica el interés en el desarrollo de dispositivos específicos para el aprovechamiento de las corrientes marinas y de las olas, junto con una pequeña clasificación en función de la profundidad del agua en la zona de instalación de estos dispositivos. Para los convertidores de energía de las olas, generalmente, de tipo resonante, se presenta una metodología de tipo general, analizando los distintos campos de fuerzas actuantes y los métodos de obtención de las respuestas temporal y frecuencial. Para los dispositivos de aprovechamiento de las corrientes, se propone una metodología simplificada de modelado dinámico que puede ser utilizada en análisis del dispositivo concreto. Para ello se tiene en cuenta los perfiles hidrodinámicos que utilizan estos dispositivos, los datos del perfil de la corriente con la profundidad y del modelo de oleaje, y la dinámica propia del conjunto multiplicadora y generador eléctrico. La metodología propuesta se aplica al estudio de un caso concreto, correspondiente a un rotor de eje horizontal de un convertidor de energía de las corrientes. Los resultados obtenidos permiten analizar los efectos del oleaje y de las condiciones de flujo de la corriente no uniforme sobre las magnitudes energéticas más importantes. Abstract: The main objective of this paper is to present the most common harnessing methods for different types of renewable energy from the sea, and to analyze energy models of the devices used for their exploitation. These models are required for the design of the device as well as for the studying of their dynamic behavior. The knowledge of these models is also necessary for dynamic simulation and for the design of control algorithms in order to achieve energy and economic optimizations. In this paper, some of the different types of ocean energy are presented and the interest in the development of specific devices for the exploitation of sea currents and waves is justified. A small classification based on the depth of water in the area where these devices are to be installed is presented too. For wave energy converters, which are generally resonant type, a general methodology is presented. The different fields of acting forces and methods for obtaining the time and frequency responses are analyzed. For devices for the exploitation of energy from sea currents, it is presented a simplified methodology of dynamic modeling that can be used in analysis of the particular device. It is taken into account the hydrodynamic profiles used in these devices, the data flow profile with depth and wave model together with the gearbox-generator set dynamics. The proposed methodology is applied to a specific case study, corresponding to a horizontal axis rotor from a device for harnessing of tidal energy. The obtained results allow to analyze the effects of wave and flow conditions of non uniform current over the most important energy variables. Palabras clave: energías renovables marinas, modelado y simulación, teoría del elemento de pala, modelado del recurso, absorbedor puntual, Keywords: marine renewable energies, modelling and simulation, blade element theory, resource modelling, point absorber

Many analyses of acoustic signals processing have been proposed for different applications over the last few years. When considering a bar-based structure, if the material through which the sound waves propagate is considered to be acoustically homogeneous and the sound speed is well known, then it is possible to determine the position and time of impact by a simple observation of the arrival times of the signals of all the transducers that are strategically disposed on the structure. This paper presents a generalized method for impact detection and location on a flat plate, together with a calibration procedure with which to obtain the sound speed from only one set of measurements. This propagation speed is not well known as a result of either imprecise material properties or the overlapping of longitudinal and transversal waves with different propagation velocities. The use of only three piezoelectric sensors allows the position and time of impact on the flat plate to be obtained when the sound speed is well known, while the use of additional sensors permits a larger detection area to be covered, helps to estimate the sound speed and/or avoids the wrong timing of difference measurements. Experimental results are presented using a robot with a specially designed knocking tool that produces impacts on a metallic flat plate.

One of the most important design constraints of a climbing robot is its own weight. When links or legs are used as a locomotion system they tend to be composed of special lightweight materials, or four-bars-linkage mechanisms are designed to reduce the weight with small rigidity looses. In these cases, flexibility appears and undesirable effects, such as dynamics vibrations, must be avoided at least when the robot moves at low speeds. The knowledge of the real tip position requires the computation of its compliance or stiffness matrix and the external forces applied to the structure. Gravitational forces can be estimated, but external tip forces need to be measured. This paper proposes a strain gauge system which achieves the following tasks: (i) measurement of the external tip forces, and (ii) estimation of the real tip position (including flexibility effects). The main advantages of the proposed system are: (a) the use of external force sensors is avoided, and (b) a substantial reduction of the robot weight is achieved in comparison with other external force measurement systems. The proposed method is applied to a real symmetric climbing robot and experimental results are presented.