Aitor J Garrido

Aitor J Garrido
Universidad del País Vasco / Euskal Herriko Unibertsitatea | UPV/EHU · Automatic Control Group - ACG

Full Professor

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185
Publications
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Publications

Publications (185)
Article
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This paper is devoted to a type of combined impulsive discrete Beverton–Holt equations in ecology when eventual discontinuities at sampling time instants are considered. Such discontinuities could be interpreted as impulses in the corresponding continuous-time logistic equations. The set of equations involve competition-type coupled dynamics among...
Chapter
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En este trabajo se ha propuesto una nueva estrategia de control para mejorar la estabilidad de turbinas eólicas flotantes (FWT). Al objeto de estudiar la reducción de oscilaciones no deseadas en el sistema, y en particular en los movimientos de cabeceo de la plataforma y de proa-popa de la nacelle, se ha considerado una plataforma tipo barcaza de f...
Chapter
En este artículo se presenta un nuevo tipo de control aplicado a una plataforma flotante multipropósito tipo barcaza capaz de aprovechar la energía eólica y undimotriz de manera simultánea. Además, los captadores de energía undimotriz se componen de columnas de agua oscilante (OWC) que ayudarán a estabilizar la plataforma y la turbina eólica flotan...
Article
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The impact of the SARS-CoV-2 (COVID-19) on the world has been partially controlled through different measures of social isolation and prophylaxis. Two new SEIR (Susceptible-Exposed-Infected-Recovered) models are proposed in order to describe this spread through different countries of Europe. In both models the infectivity of the asymptomatic period...
Article
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The implementation and integration of new methods and control techniques to floating offshore wind turbines (FOWTs) have the potential to significantly improve its structural response. This paper discusses the idea of integrating oscillating water columns (OWCs) into the barge platform of the FOWT to transform it into a multipurpose platform for ha...
Article
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In this article, a new strategy for switching control has been proposed with the aim of reducing oscillations in floating offshore wind turbines. Such oscillations lead to a shortage in the system’s efficiency, lifespan and harvesting capability of wind and wave energies. In order to study the decreasing of undesired oscillations in the system, par...
Article
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This paper studies a new extended SEIR (susceptible-exposed-infectious recovered) epidemic model which incorporates the contribution of infective contagions to the resident population from infective exposed (Eo) and infectious (Io) outsiders as well as eventual delayed re-susceptibility by partial loss of immunity. It is referred to as a SEIRDEoIo...
Article
This paper presents the design and implementation of a supervisory control and data acquisition (SCADA) system for automatic fault detection. The proposed system offers advantages in three areas: the prognostic capacity for preventive and predictive maintenance, improvement in the quality of the machined product and a reduction in breakdown times....
Article
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Undesired motions in Floating OffshoreWind Turbines (FOWT) lead to reduction of system efficiency, the system’s lifespan, wind and wave energy mitigation and increment of stress on the system and maintenance costs. In this article, a new barge platform structure for a FOWT has been proposed with the objective of reducing these undesired platform mo...
Article
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Two discrete mathematical SIR models (Susceptible-Infectious-Recovered) are proposed for modelling the propagation of the SARS-CoV-2 (COVID-19) through Spain and Italy. One of the proposed models is delay-free while the other one considers a delay in the propagation of the infection. The objective is to estimate the transmission, also known as infe...
Article
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This paper gives simple rules to calculate the transmission rate and some other parameters in COVID- 19 from recorded data on the infection, recovery and death through several SIR-based epidemic models. In particular, it is emphasized how the transmission rate is highly dependent on the quarantine or confinement interventions. The proposed rules es...
Article
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This paper presents an ANN-based rotational speed control to avoid the stalling behavior in Oscillating Water Columns composed of a Doubly Fed Induction Generator driven by a Wells turbine. This control strategy uses rotational speed reference provided by an ANN-based Maximum Power Point Tracking. The ANN-based MPPT predicts the optimal rotational...
Conference Paper
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In this paper, the Harmony Search (HS) algorithm and the Improved Harmony Search (IHS) algorithm were implemented and tested to optimize the control design of the Proportional-Integral-Derivative (PID) controller in an airflow control scheme. The airflow control strategy has been proposed to deal with the undesired stalling phenomenon of the Wells...
Conference Paper
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This paper presents the design and development of an Artificial Neural Network (ANN) capable of estimating the required airflow speed for an airflow control strategy used to prevent the stalling phenomenon in Oscillating Water Columns. The ANN is trained to recognize incoming waves susceptible to provoke the stalling behavior. The proposed control...
Conference Paper
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In this paper, a new barge platform structure for a Floating Offshore Wind Turbine (FOWT) has been proposed in an effort to increase its stability. The new barge structure aims to reduce the platform's rotational and translational moments and the tower displacements. This is achieved by installing Oscillating Water Columns (OWC) within the barge to...
Article
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This paper studies and proposes some supervisory techniques to update the vaccination and control gains through time in a modified SI (susceptible-infectious) epidemic model involving the susceptible and subpopulations. Since the presence of linear feedback controls are admitted, a compensatory recovered (or immune) extra subpopulation is added to...
Article
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A centralized airflow control scheme for a complex ocean energy network (OEN) is proposed in this paper to reduce the output power variation (OPV). The OEN is an integrated network of multiple oscillating water columns (OWCs) that are located at different geographical sites connected to a common electrical grid. The complexity of the OWC-OEN increa...
Article
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The Harmony Search algorithm has attracted a lot of interest in the past years because of its simplicity and efficiency. This led many scientists to develop various variants for many applications. In this paper, four variants of the Harmony search algorithm were implemented and tested to optimize the control design of the Proportional-Integral-deri...
Article
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Global optimization problems are mostly solved using search methods. Therefore, decreasing the search space can increase the efficiency of their solving. A widely exploited technique to reduce the search space is symmetry-breaking, which helps impose constraints on breaking existing symmetries. The present article deals with the airflow control opt...
Article
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This paper studies the representation of a general epidemic model by means of a first-order differential equation with a time-varying log-normal type coefficient. Then the generalization of the first-order differential system to epidemic models with more subpopulations is focused on by introducing the inter-subpopulations dynamics couplings and the...
Article
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The authors would like to add the following note to Figure 7 of their paper published in Energies [...]
Book
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This is a reprint of articles from the Special Issue published online in the open access journal Energies (ISSN 1996-1073) from 2018 to 2019 (available at: https://www.mdpi.com/journal/energies/special issues/marine).
Article
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The generated power of Oscillating Water Columns (OWC) based on Wells turbines is limited due to the stalling behavior. Therefore, this paper presents the modeling of an OWC and a rotational speed control using a novel Fuzzy Gain Scheduled-Sliding Mode controller (FGS-SMC) for a stalling-free operation. The proposed SMC-rotational speed control wil...
Article
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Oscillating water column (OWC) plants face power generation limitations due to the stalling phenomenon. This behavior can be avoided by an airflow control strategy that can anticipate the incoming peak waves and reduce its airflow velocity within the turbine duct. In this sense, this work aims to use the power of artificial neural networks (ANN) to...
Article
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At present, two main magnetic confinement fusion devices exist: tokamaks and stellarators. Moreover, stellarators have been demonstrated to be a good alternative to tokamaks, due to their ability to operate in continuous mode, which eventually translates into a higher commercial profitability. In stellarators, the magnetic confinement of the plasma...
Article
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This paper relied on the investigation of the properties of the stage-structured model of coupled larvae and adult mosquito populations’ evolution when parameterized, in general, by time-varying (or stage-dependent) sequences. In particular, the investigated properties were the non-negativity of the solution under non-negative initial conditions, t...
Article
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Wave energy's path towards commercialization requires maximizing reliability, survivability, an improvement in energy harvested from the wave and efficiency of the wave to wire conversion. In this sense, control strategies directly impact the survivability and safe operation of the device, as well as the ability to harness the energy from the wave....
Article
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Fusion power is the most significant prospects in the long-term future of energy in the sense that it composes a potentially clean, cheap, and unlimited power source that would substitute the widespread traditional nonrenewable energies, reducing the geographical dependence on their sources as well as avoiding collateral environmental impacts. Alth...
Article
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Oscillating Water Column (OWC) based devices are arising as one of the most promising technologies for wave energy harnessing. However, the most widely used turbine comprising its power take-off (PTO) module, the Wells turbine, presents some drawbacks that require special attention. Notwithstanding different control strategies are being followed to...
Article
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Control engineering in renewable energy systems is a delicate and tedious task, especially due to the unpredictable nature of the renewable resources, which requires precision and robustness. These requirements can be ensured using intelligent control, which provides better performance than many conventional techniques and methods. This paper focus...
Article
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Energy originating in tidal and ocean currents appears to be more intense and predictable than other renewables. In this area of research, the Tidal Stream Generator (TSG) power plant is one of the most recent forms of renewable energy to be developed. The main feature of this energy converter is related to the input resource which is the tidal cur...
Article
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Artificial Intelligence techniques have shown outstanding results for solving many tasks in a wide variety of research areas. Its excellent capabilities for the purpose of robust pattern recognition which make them suitable for many complex renewable energy systems. In this context, the Simulation of Tidal Turbine in a Digital Environment seeks to...
Conference Paper
This paper deals with the modeling and control of the NEREIDA wave generation power plant installed in Mutriku, Spain. This kind of Oscillating Water Column (OWC) plants usually employ a Wells turbine coupled to a Doubly Fed Induction Generator (DFIG). The stalling behavior of the Wells turbine limits the generated power. In this context, a sliding...
Article
Numerous control schemes have been proposed to reach a more efficient power generation using Wells turbine-based Oscillating-Water-Column (OWC) power plants. Most of these control strategies aim to avoid the stalling behavior, a feature of the Wells turbine, that limits the generated power. Besides, the plant must be able to maintain its performanc...
Article
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Artificial intelligence technologies are widely investigated as a promising technique for tackling complex and ill-defined problems. In this context, artificial neural networks methodology has been considered as an effective tool to handle renewable energy systems. Thereby, the use of Tidal Stream Generator (TSG) systems aim to provide clean and re...
Conference Paper
The NEREIDA wave generation power plant installed in Mutriku, Spain is a multiple Oscillating Water Column (OWC) plant. The power take-off consists of a Wells turbine coupled to a Doubly Fed Induction Generator (DFIG). The stalling behavior present in the Wells turbine limits the generated power. This paper presents the modeling and a Harmony Searc...
Article
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The effects of climate change and global warming reveal the need to find alternative sources of clean energy. In this sense, wave energy power plants, and in particular Oscillating Water Column (OWC) devices, offer a huge potential of energy harnessing. Nevertheless, the conversion systems have not reached a commercially mature stage yet so as to c...
Article
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Oceans, and particularly waves, offer a huge potential for energy harnessing all over the world. Nevertheless, the performance of current energy converters does not yet allow us to use the wave energy efficiently. However, new control techniques can improve the efficiency of energy converters. In this sense, the plant sensors play a key role within...
Article
Wave energy power plants, particularly Oscillating Water Column devices, become a feasible alternative to reduce the dependence on fossil fuels and slow down the growing problem of the global warming. Thus, new control schemes can play an important role, providing performance improvements to compete from a commercial point of view with the other tr...
Conference Paper
This paper formalizes the consensus for linear dynamic systems in a linear algebraic generic context. Basically, the consensus is understood as the ability of achievement of a prescribed finite- time common error in-between each pair of components of the consensus signal.
Article
The stalling behavior is a feature of the Wells turbine that limits the generated output power of power plants using this turbine. The NEREIDA wave power plant installed in the harbor of Mutriku in the northern Spanish shoreline constitutes an excellent example of this phenomenon. This article deals with the modeling, simulation, and control of an...
Article
Full-text available
Las centrales de aprovechamiento de la energía proveniente de las olas, y particularmente los dispositivos de columna de agua oscilante, resultan una alternativa factible para reducir la dependencia de los combustibles fósiles y frenar el creciente problema del calentamiento global. Así, los nuevos esquemas de control pueden jugar un papel importan...
Article
The rising use of renewable power generation plants is highlighting the need for an integrated research combining multiple disciplines in order to achieve a commercially competitive technology stage. The demonstrative NEREIDA wave power plant installed in the northern coast of Spain constitutes a good example of this effort. This paper deals with t...
Article
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The latest forecasts on the upcoming effects of climate change are leading to a change in the worldwide power production model, with governments promoting clean and renewable energies, as is the case of tidal energy. Nevertheless, it is still necessary to improve the efficiency and lower the costs of the involved processes in order to achieve a Lev...
Conference Paper
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This paper deals with the modeling, simulation and control of a wave power plant installed on the northern coast of Spain. This plant is an onshore Oscillating Water Column (OWC) composed of a Wells turbine coupled to a Doubly Fed Induction Generator (DFIG). The power generated by the OWC is limited by the stalling behavior, a feature of the Wells...
Article
Full-text available
This paper investigates sufficient conditions of almost periodic sand periodic solutions of an integral model under impulsive controls. Since the model is of generic epidemiological interest, such impulsive controls are either vaccination actions or abrupt variations of the infected population due to infected immigration or lost of infective number...