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Adaptación del programa de control numérico EMC para el control de un manipulador paralelo y puesta en marcha del controlador
(2007) Plaza Puértolas, Aitor; Ros Ganuza, Javier; Escuela Técnica Superior de Ingenieros Industriales y de Telecomunicación; Telekomunikazio eta Industria Ingeniarien Goi Mailako Eskola Teknikoa; Ingeniería Mecánica, Energética y de Materiales; Mekanika, Energetika eta Materialen Ingeniaritza
Open Access
Mechanical sensitivity analysis of strain gauge configurations in the main shaft of wind turbines
(IOP Publishing, 2022) Bacaicoa Díaz, Julen; Iriarte Goñi, Xabier; Aginaga García, Jokin; Plaza Puértolas, Aitor; Ingeniaritza; Institute of Smart Cities - ISC; Ingeniería
Wind turbines are reaching their remaining useful life, thus it is important to guarantee the well status of its components. A common way to check the status is to measure the loads on the Low Speed Shaft with strain gauges, but not always are bonded perfectly. In this work a sensitivity analysis of strain gauge con gurations is carried out, where the infuence of geometric and material parameters, and misplacement and misalignment parameters is analyzed. An analytical model for a single gauge was developed, obtaining a relation between the exerted loads and the strain measured by the strain gauge. By means of Taylor approximations the estimated loads were approached in order to have into account the in uence of the uncertainty of parameters. Results shown that the sensitivities with respect to the geometric and material parameters did not depend on the secondary loads while in the sensitivities with respect to the gauge bonding parameters the cross-talk e ect was present. In order to obtain realistic numerical results, a horizontal-axis NREL 5-MW wind turbine was simulated in OpenFAST with two wind-speed scenarios. The uncertainty of the estimated loads by the strain gauge con gurations was calculated.
Open Access
Modelado simbólico para la simulación en tiempo real de sistemas multicuerpo
(2016) Plaza Puértolas, Aitor; Ros Ganuza, Javier; Ingeniería Mecánica, Energética y de Materiales; Mekanika, Energetika eta Materialen Ingeniaritza
Esta tesis se sitúa dentro del contexto de los métodos simbólicos en la dinámica de sistemas multicuerpo y recoge la experiencia de 25 años en este contexto. La situación anterior a la tesis era la de una librería simbólica C++ que permitía plantear las ecuaciones dinámicas de la mecánica pero con ciertas limitaciones. La más importante posiblemente eran los grandes tiempos de ejecución para la generación de las ecuaciones del sistemas dinámico (código en C que luego se compila para obtener un ejecutable) que incluso para problemas simples podía tardar horas. Además, la exportación de las ecuaciones dinámicas no era óptima en el número de operaciones. El doctorando ha estado involucrado en diversos proyectos de investigación, en uno de ellos (el más demandante respecto a las ecuaciones dinámicas) se modelaba una locomotora de ferrocarril, que tardaba en general las ecuaciones dinámicas unos 8000s y se necesitaba MAPLE para optimizar las ecuaciones, ya que no eran muy óptimas. Después de la tesis el tiempo de generar las ecuaciones es 800s y el número de operaciones del código generado es el 50% y MAPLE no es necesario. Estas cifras son extrapolables a otros problemas. El estado del arte en multicuerpo simbólico son los trabajos de J.C. Samin y P. Fisette, al menos en lo que se refiere a publicaciones, aunque J. McPhee ha colaborado en la creación de MapleSym, que es un motor simbólico de renombre. Hay también otros trabajos como el sofware NewEuler 2C y 2M. Los más avanzados son los que utilizan formulaciones recursivas, pero están limitados por la implementación que ellos realizan en su software y por el tipo de coordenadas. En esta tesis doctoral se ha desarrollado un algebra de operadores y estructuras de datos de la dinámica que permiten la implementación de cualquier formalismo con cualquier tipo de coordenadas y obtener unas ecuaciones simbólicas muy óptimas. Con lo cual se eliminan las limitaciones del formalismo y del tipo de coordenadas. Esto presenta innumerables ventajas. Además, los tiempos computacionales y la calidad del código generado es similar al de estos que tomamos como referencia. Finalmente, se presenta un algoritmo que evitaría la aparición de expresiones susceptibles de simplificación trigonométrica, que es uno de los problemas más graves en la generación de ecuaciones simbólicas óptimas. Para ello, se propone un nuevo algebra de vectores, denominados extendidos, que pasa desapercibida al usuario, y que permitiría la generación de código más óptimo, más rápido y con menores recursos de memoria. Todos los demás algoritmos simbólicos existentes en un momento u otro requieren simplificar trigonométricamente si quieren obtener expresiones lo más óptimas posibles.
Open Access
Symbolic multibody methods for real-time simulation of railway vehicles
(Springer, 2018) Ros Ganuza, Javier; Plaza Puértolas, Aitor; Iriarte Goñi, Xabier; Pintor Borobia, Jesús María; Ingeniería Mecánica, Energética y de Materiales; Mekanika, Energetika eta Materialen Ingeniaritza
In this work, recently developed state-of-the-art symbolic multibody methods are tested to accurately model a complex railway vehicle. The model is generated using a symbolic implementation of the principle of virtual power. Creep forces are modeled using a direct symbolic implementation of the standard linear Kalker model. No simplifications, such as base parameter reduction, partial-linearization or lookup tables for contact kinematics, are used. An Implicit–Explicit integration scheme is proposed to efficiently deal with the stiff creep dynamics. Real-time performance is achieved: the CPU time required for a very robust 1 ms integration time step is 203 µs.
Open Access
4P operational harmonic and blade vibration in wind turbines: a real case study of an active yaw system and a concrete tower
(Elsevier, 2024) Torres Elizondo, Antonio; Gil Soto, Javier; Plaza Puértolas, Aitor; Aginaga García, Jokin; Ingeniería; Ingeniaritza; Institute of Smart Cities - ISC; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
This study aims to comprehensively investigate the impact of mechanical loads on the performance and lifetime of wind turbines, with particular emphasis on blade vibration at the 4P operational harmonic. Experiments and advanced aeroelastic simulations are combined to assess how active yaw systems and concrete towers affect this specific vibration. Contrary to previous assumptions, field tests have shown that there is a resonance phenomenon in the blade. Specifically, the first edgewise mode of the blade resonates at the 4P frequency, which did not happen in the aeroelastic simulations. Remarkably, thorough aeroelastic simulations show that this resonance is triggered by the excitation of the Edgewise Backward Whirling mode of the rotor, which occurs at the 3P operating harmonic. This study highlights the need for accurate and precise modelling using aeroelastic simulations to reproduce the resonance phenomenon and analyse the contributing factors. A major breakthrough is the discovery that stiffening the active yaw system significantly reduces the 3P hub fixed motions, resulting in reduced blade vibration at the 4P frequency. Furthermore, the simulations show the sensitivity of the 4P vibration to different wind characteristics, providing valuable insights for the design of wind turbines in different environmental conditions.
Open Access
Ultra-low frequency multidirectional harvester for wind turbines
(Elsevier, 2023) Castellano Aldave, Jesús Carlos; Carlosena García, Alfonso; Iriarte Goñi, Xabier; Plaza Puértolas, Aitor; Ingeniería; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
In this paper we propose, and demonstrate through a prototype, a completely novel device able to harvest mechanical energy from the multidirectional vibrations in a wind turbine, and convert it into electrical, to power autonomous sensors. The application is very challenging since vibrations are of ultra-low frequency, well below 1 Hz, with accelerations of tenths of cm/s2 (0.01 g), and the device must capture energy from the movement in any direction. According to our experiments, the device is capable to generate average powers around the milliwatt in the operation conditions of a wind turbine, which are enough for some very-low power sensor nodes, or at least to considerably extend the life-time of batteries. The device is based on the principle of moving (inertial) masses comprised of magnets in Hallbach arrays interacting with coils, and can work for movements on any direction of a plane. To the best of our knowledge, this is the first device specifically proposed for wind turbines and one of the few that work in such low frequencies, and capture energy from movements on any direction on a plane. Only three harvesters proposed in the literature, intended for distinct applications, can work at such low frequencies, and our device exhibits a better efficiency. Though comparisons with harvesters working in different contexts and, even using different conversion principles, is not completely fair, we make in this paper a comparison to the closest ones, resorting to two different figures of merit.
Open Access
Mode-displacement method for structural dynamic analysis of bio-inspired structures: a palm-tree stem subject to wind effects
(Taylor & Francis, 2022) Plaza Puértolas, Aitor; Vargas Silva, Gustavo Adolfo; Iriarte Goñi, Xabier; Ros Ganuza, Javier; Ingeniería; Ingeniaritza
Biological materials (orthotropic materials), like wood, can offer good mechanical properties with a minimum amount of material, making their internal structure the suitable one to be applied on bio-inspired structures. The knowledge of the exceptional structural performance of palm trees, and specially its response to different loading conditions, provides useful information when lightweight structures with high slenderness ratio are desired. Recent researches focused on the analysis of palm trees subject to static loading conditions, ignoring the fluctuating nature of the wind speed. The purpose of this study is to simulate in a computational efficient way the effect of dynamic loading conditions applied on palm trees. Using the mode displacement method, the number of degrees of freedom of a dynamic finite element analysis can be drastically reduced with a minimal loss of accuracy. It was applied to simulate the behavior of structures comprised of an orthotropic material subject to a stochastic dynamic load. The influence of the number of selected degrees of freedom has also been studied. In addition, an exponential integration method is proposed to perform the time integration procedure. The results obtained show that a properly reduced model suitably represents the full finite element model without any appreciable loss of accuracy; it is also shown that computational cost can be drastically reduced. This method could give an appropriate computational representation of the behavior of orthotropic structures, and it could be used for studying more complex bio-inspired structures.
Open Access
Along-the-path exponential integration for Floquet stability analysis of wind turbines
(IOP Publishing, 2022) Ros Ganuza, Javier; Olcoz Alonso, Álvaro; Plaza Puértolas, Aitor; Zientziak; Institute of Smart Cities - ISC; Ciencias; Gobierno de Navarra / Nafarroako Gobernua
Traditionally, stability assessment of wind turbines has been performed by eigenanalysis of the azimuthally-averaged linearized system after applying the Multi-Blade Coordinate (MBC) transformation. However, due to internal or external anisotropy, the MBC transform does not produce an exact Linear Time-Invariant (LTI) system, and a Floquet analysis is required to capture the influence of all periodic terms, leading to a more accurate stability analysis. In this paper exponential integration methods that use system linearizations at different blade azimuth positions are used to integrate the perturbed system state and compute the Floquet monodromy matrix. The proposed procedure is assessed for a simple 6 DOF wind turbine model and a more complex aeroelastic model of a 5MW onshore wind turbine. The defined along-the-path or moving-point exponential integrator is found to be the suitable in order to perform a Floquet stability analysis even using a coarse linearization grid.
Open Access
Dataset for the identification of a ultra-low frequency multidirectional energy harvester for wind turbines
(Elsevier, 2024-11-20) Bacaicoa Díaz, Julen; Hualde Otamendi, Mikel; Merino Olagüe, Mikel; Plaza Puértolas, Aitor; Iriarte Goñi, Xabier; Castellano Aldave, Jesús Carlos; Carlosena García, Alfonso; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Ingeniería; Ingeniaritza; Institute of Smart Cities - ISC; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
This paper presents a publicly available dataset designed to support the identification (characterization) and performance optimization of an ultra-low-frequency multidirectional vibration energy harvester. The dataset includes detailed measurements from experiments performed to fully characterize its dynamic behaviour. The experimental data encompasses both input (acceleration)-output (energy) relationships, as well as internal system dynamics, measured using a synchronized image processing and signal acquisition system. In addition to the raw input-output data, the dataset also provides post-processed information, such as the angular positions of the moving masses, their velocities and accelerations, derived from recorded high-speed videos at 240 Hz. The dataset also includes the measured power output generated in the coils. This dataset is intended to enable further research on vibration energy harvesters by providing experimental data for identification, model validation, and performance optimization, particularly in the context of energy harvesting in low-frequency and multidirectional environments, such as those encountered in wind turbines.
Open Access
Low-frequency electromagnetic harvester for wind turbine vibrations
(Elsevier, 2024) Castellano Aldave, Jesús Carlos; Plaza Puértolas, Aitor; Iriarte Goñi, Xabier; Carlosena García, Alfonso; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC; Ingeniería; Ingeniaritza; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
In this paper we describe and fully characterize a novel vibration harvester intended to harness energy from the vibration of a wind turbine (WT), to potentially supply power to sensing nodes oriented to structural health monitoring (SHM). The harvester is based on electromagnetic conversion (EM) and can work with vibrations of ultra-low frequencies in any direction of a plane. The harvester bases on a first prototype already disclosed by the authors, but in this paper, we develop an accurate model parameterized by a combination of physical parameters and others related to the geometry of the device. The model allows predicting not only the power generation capabilities, but also the kinematic behaviour of the harvester. Model parameters are estimated by an identification procedure and validated experimentally. Last, the harvester is tested in real conditions on a wind turbine.