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    Canceling output disturbances in observer design through internal model filters

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    This work proposes a redesign method for nonlinear observers to reduce the effect of a particular class of output disturbances. Specifically, it is considered a disturbance composed of a term generated from a known system and an unstructured term. The proposed approach does not require modifying the original observer and is based on adding a simple filter that includes an internal model of the disturbance generator. Sufficient conditions for stability of the proposed filter-observer architecture are given. Moreover, the approach is validated through numerical simulations.This research was partially supported by the French Grant ANR ALLIGATOR (ANR-22-CE48-0009-01), by the Spanish Ministry of Universities funded by the European Union - NextGenerationEU (2022UPC-MSC-93823). This work is part of the Project MAFALDA (PID2021-126001OB-C31) funded by MCIN/ AEI /10.13039/501100011033 and by ”ERDF A way of making Europe”. This work is part of the project MASHED (TED2021- 129927B-I00), funded by MCIN/ AEI/10.13039/501100011033 and by the European Union Next GenerationEU/PRTR.Peer ReviewedPreprin

    Disseny i fabricació d'un sistema de refrigeració per un sistema de frenada d'un automòbil

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    El presente proyecto tiene como propósito principal el desarrollo del diseño de una entrada de aire para la refrigeración de un freno de disco ventilado de un BMW Z3. Para ello se analizará el funcionamiento de un sistema de frenado, desde los principios físicos que rigen el proceso de frenado hasta el diseño 3D de las piezas esenciales para mejorar la refrigeración del conjunto. La metodología de este trabajo se basará en un enfoque integral que combina el análisis teórico del sistema de frenos, la aplicación de técnicas avanzadas de diseño asistido por ordenador (CAD) para modelar las piezas necesarias y, finalmente, la simulación numérica mediante Dinámica de Fluidos Computacional (CFD) para evaluar la eficacia de la entrada de aire propuesta. Este proyecto no solo busca optimizar el rendimiento del sistema de frenos, sino que también pretende contribuir al conocimiento en el campo de la ingeniería automotriz, proporcionando una solución práctica respaldada por fundamentos teóricos y simulaciones avanzadas. A lo largo de este documento, exploraremos los fundamentos teóricos, los procesos de diseño, la simulación CFD y, en última instancia, propondremos una solución innovadora para mejorar la eficiencia de los frenos delanteros de un vehículo.The main purpose of this project is the development of the design for an air inlet to cool a ventilated disc brake. To achieve this, we will analyze the operation of a braking system, from the physical principles governing the braking process to the 3D design of essential components aimed at enhancing the overall cooling. The methodology of this work will rely on a comprehensive approach that combines theoretical analysis of the braking system, the application of advanced computer-aided design (CAD) techniques to model necessary parts, and, finally, numerical simulation using Computational Fluid Dynamics (CFD) to assess the effectiveness of the proposed air inlet. This project not only seeks to optimize the performance of the braking system but also aims to contribute to knowledge in the field of automotive engineering, providing a practical solution supported by theoretical foundations and advanced simulations. Throughout this document, we will explore theoretical foundations, design processes, CFD simulation, and, ultimately, propose an innovative solution to enhance the efficiency of a vehicle's front brakes

    A benchmark for Monte Carlo simulations in gamma-ray spectrometry part II: true coincidence summing correction factors

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    The goal of this study is to provide a benchmark for the use of Monte Carlo simulation when applied to coincidence summing corrections. The examples are based on simple geometries: two types of germanium detectors and four kinds of sources, to mimic eight typical measurement conditions. The coincidence corrective factors are computed for four radionuclides. The exercise input files and calculation results with practical recommendations are made available for new users on a dedicated webpage.Article signat per 26 autors/es: M.-C. Lépy, C. Thiam, M. Anagnostakis, C. Cosar, A. de Blas, H. Dikmen, M.A. Duch, R. Galea, M.L. Ganea, S. Hurtado, K. Karfopoulos, A. Luca, G. Lutter, I. Mitsios, H. Persson, C. Potiriadis, S. Röttger, N. Salpadimos, M.I. Savva, O. Sima, T.T. Thanh, R.W. Townson, A. Vargas, T. Vasilopoulou, L. Verheyen, T. VidmarPostprint (author's final draft

    Resolució del segon parcial de Matemàtica Discreta

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    Resolved2023/20241r quadrimestr

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    Guia temàtica Biblioteca ETSAB: Palau Maldà

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    Bibliografia sobre el Palau Maldà. Gran casal residencial edificat per la família Cortada, posteriorment barons de Maldà, durant el segle XVII. A la seva època va ser el palau privat més gran de Barcelona, amb un jardí interior i una sumptuosa decoració barroca a totes les seves estances. Aquí va viure-hi el baró de Maldà, autor del popular Calaix de Sastre. Al segle XIX va passar per matrimoni als marquesos de Castellbell i després de la Guerra Civil es va transformar en apartaments. Des de l'any 1942 els seus baixos estan ocupats per les Galeries Maldà. (Font de la descipció: Pobles de Catalunya: www.poblesdecatalunya.cat)Postprint (author's final draft

    Controlled dopamine release from cellulose-based conducting hydrogel

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    Very recently, the controlled release of dopamine (DA), a neurotransmitter whose deficiency is associated with Parkinson's disease, has been postulated as a good alternative to the oral administration of levodopa (L-Dopa), a dopamine precursor, to combat the effects of said disease. However, this is still a very little explored field and there are very few carriers that are capable of releasing DA, a small and water-soluble molecule, in an efficient and controlled manner. In this work, we report a carrier based on a conductive hydrogel capable of loading DA and releasing it progressively and efficiently (100 % release) in a period of five days by applying small electrical stimuli (–0.4 V) daily for a short time (1 min). The hydrogel (CMC/PEDOT), which is electrically active, has been prepared from sodium carboxymethylcellulose and poly(3,4-ethylenedioxythiophene) microparticles, using citric acid as a cross-linking agent. Furthermore, the results have shown that when relatively hydrophobic small molecules, such as chloramphenicol, are loaded, the electrostimulated release is significantly less efficient, demonstrating the usefulness of CMC/PEDOT as a carrier for neurotransmitters.Postprint (author's final draft

    High-order cell-centered finite volume method for solid dynamics on unstructured meshes

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    This paper introduces a high-order finite volume method for solving solid dynamics problems on three-dimensional unstructured meshes. The method is based on truncated Taylor series constructed about each control volume face using the least squares method, extending the classical finite volume method to arbitrary interpolation orders. As verification tests, a static analytical example for small deformations, a hyperelastic cantilever beam with large deformations, and a cantilever beam subject to a dynamic load are analyzed. The results provide an optimal set of parameters for the interpolation method and allow a comparison with other classic schemes, yielding to improved results in terms of accuracy and computational cost. The final test consists in the simulation of a compressor reed valve in a dynamic scenario mimicking real-life conditions. Numerical results are compared against experimental data in terms of displacements and velocity; then, a comprehensive physical analysis of stresses, caused by bending and impact of the valve, is carried out. Overall, the method is demonstrated to be accurate and effective in handling shear locking, stress concentrations, and complex geometries and improves the effectiveness of the finite volume method for solving structural problems.The authors acknowledge Voestalpine Precision Strip AB company for the previous research collaboration project that allows to experimentally validate the numerical method presented. P. Castrillo gratefully acknowledges the Universitat Politècnica de Catalunya and Banco Santander for the financial support of his predoctoral grant FPI-UPC (109 FPI-UPC 2018). E. Schillaci acknowledges the financial support of the Programa Torres Quevedo (PTQ2018-010060). The authors would like to thank Professor Alfredo Canelas for his support during the development of the current work.Peer ReviewedPostprint (author's final draft

    Probabilistic model of traffic scenarios for extreme load effects in long-span bridges

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    The traffic scenarios that may cause extreme load effects are of great importance to the safety assessment of bridge structures. The traditional simulation method of traffic flow cannot depict the distribution pattern of vehicles on the bridge deck when the maximum effect is induced. In this paper, a probabilistic Gaussian mixture model (GMM) for heavy vehicle scenarios on the bridge deck under free-flow condition is proposed for long-span bridges based on collected Weigh in Motion (WIM) data. The scenarios of extreme response under free-flow occur more frequently than congestion scenarios and are of similar value and relevance in the daily management and safety assessment of long-span bridges. A non-stationary Poisson process is utilized to simulate the uneven occurrence of heavy vehicles in different lanes, and it is assumed that they are located within the artificially defined cells on the bridge deck. Then, Nataf transformation is employed to consider the correlation of gross vehicle weights (GVWs) within close range in the same lane. The numerical study is carried out on a long-span cable-stayed bridge to investigate the effects of correlation in GVWs and stationarity of vehicle distribution location on the structural responses. The load responses calculated by the proposed model and Monte Carlo method for different effects are compared with the values derived from code model. The results show that with the increase of the correlation level of the neighboring GVWs, the simulated responses are more prone to get extreme values, which means an increasing probability of the most unfavorable spatial distribution of on-bridge vehicles. The same results are also found under the non-stationary simulation state for vehicle location. The non-stationary Poisson process provides an efficient, highly feasible method, which is also in the safe side, for simulating the vehicle spatial distribution for specific effects.The support from the National Natural Science Foundation of China (Grant number 51878495), the Academician Project Foundation of CCCC (Grant numbers: YSZX-01-2020-01-B), the National Key R&D Program of China (Grant number 2018YFB1600100) and the Shanghai Sailing Program (Grant number: 21YF1449300) is gratefully acknowledged. The opinions and conclusions presented in this article are those of the authors and do not necessarily reflect the views of the sponsoring organizations.Peer ReviewedPostprint (author's final draft

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