Feedback linearization control for a distributed solar collector field

This article describes the application of a feedback linearization technique for control of a distributed solar collector field using the energy from solar radiation to heat a fluid. The control target is to track an outlet temperature reference by manipulating the fluid flow rate through the solar field, while attenuating the effect of disturbances (mainly radiation and inlet temperature). The proposed control scheme is very easy to implement, as it uses a numerical approximation of the transport delay and a modification of the classical control scheme to improve startup in such a way that results compared with other control structures under similar conditions are improved while preserving short commissioning times. Experiments in the real plant are also described, demonstrating how operation can be started up efficiently.Ministerio de Ciencia y Tecnología DPI2004-07444-C04-04Ministerio de Ciencia y Tecnología DPI2005-0286

A Robust Constrained Reference Governor Approach using Linear Matrix Inequalities

The purpose of this paper is to examine and provide a solution to the output reference tracking problem for uncertain systems subject to input saturation. As well-known, input saturation and modelling errors are very common problems at industry, where control schemes are implemented without accounting for such problems. In many cases, it is sometimes difficult to modify the existing implemented control schemes being necessary to provide them with external supervisory control approaches in order to tackle problems with constraints and modelling errors. In this way, a cascade structure is proposed, combining an inner loop containing any proper controller with an outer loop where a generalized predictive controller (GPC) provides adequate references for the inner loop considering input saturations and uncertainties. Therefore, the contribution of this paper consists in providing a state space representation for the inner loop and using linear matrix inequalities (LMI) to obtain a predictive state-vector feedback in such a way that the input reference for the inner loop is calculated to satisfy robust tracking specifications considering input saturations. Hence, the final proposed solution consists in solving a regulation problem to a fixed reference value subjected to a set of constraints described by several LMI and bilinear matrix inequalities (BMI). The main contribution of the paper is that the proposed solution is a non-linear setpoint tracking approach, that is, it is allowed that the system goes into saturation facing the problem of setpoint tracking instead of regulating to the origin. An illustrative numerical example is presented.Ministerio de Ciencia y Tecnología DPI2004-07444-C04-01/0

Influencia de la autoconfianza y el perfil motivacional en el “flujo” en matemáticas

Varios autores consideran que la motivación y el afecto son fundamentales en el aprendizaje de matemáticas, por su influencia en el rendimiento académico de los estudiantes y en su elección de actividades matemáticas. El flujo está asociado a la motivación intrínseca, y se produce cuando los sujetos experimentan alta concentración y disfrute con la actividad que están realizando. La variable afectiva autoconfianza es la creencia sobre la propia competencia matemática. El perfil motivacional se caracteriza mediante la combinación de distintas metas académicas. En este estudio se analiza, a través de cuestionarios, la influencia de la autoconfianza y del perfil motivacional en experiencias de flujo en matemáticas. La muestra está integrada por 161 estudiantes del grado de Maestro de Educación Primaria

Nota de Redacción

[ES] Nota de redacción del vol. 18, nº 4 de RIAI.Berenguel, M.; Santos, M. (2021). Nota de Redacción. Revista Iberoamericana de Automática e Informática industrial. 18(4):ii-ii. http://hdl.handle.net/10251/173778OJSiiii18

Very high-energy γ-ray observations of the Crab nebula and other potential sources with the GRAAL experiment

The “γ-ray astronomy at Almeria” (GRAAL) experiment uses 63 heliostat-mirrors with a total mirror area of ≈2500 m2 from the CESA-1 field at the “Plataforma Solar de Almeria” to collect Cherenkov light from air showers. The detector is located in a central solar tower and detects photon-induced showers with an energy threshold of 250±110 GeV and an asymptotic effective detection area of about 15 000 m2. A comparison between the results of detailed Monte-Carlo simulations and data is presented. Data sets taken in the period September 1999–September 2000 in the direction of the Crab pulsar, the active galaxy 3C 454.3, the unidentified γ-ray source 3EG J1835+59 and a “pseudosource” were analyzed for high energy γ-ray emission. Evidence for a γ-ray flux from the Crab pulsar with an integral flux of 2.2±0.4 above threshold and a significance of 4.5σ in a total measuring time of 7 h and 10 min on source was found. No evidence for emission from the other sources was found. Some difficulties with the use of heliostat fields for γ-ray astronomy are pointed out. In particular the effect of field-of-view restricted to the central part of a detected air shower on the lateral distribution and timing properties of Cherenkov light are discussed. Upon restriction the spread of the timing front of proton-induced showers sharply decreases and the reconstructed direction becomes biased towards the pointing direction. This is shown to make efficient γ-hadron separation difficult

The GRAAL Project

26th International Cosmic Ray Conference Salt Lake City, Utah August 17-25,1999The GRAAL Project (Gamma Ray Astronomy at ALmeria) makes use of the CESA-1 heliostat field at the “Plataforma Solar de Almeria” (Spain) as a gamma-ray telescope with an energy threshold of about 100 GeV. Cherenkov light generated by EAS is reflected by the heliostats and collected into photomultipliers (PMTs) with nonimaging secondary optics. Each PMT collects the light reflected by 13 - 18 heliostats of 40 m2 using a Winston cone. After successful tests with two collecting cones, a more advanced setup on a dedicated platform, using four collectors and 63 heliostats (total reflecting area of about 2500 m2 ) is being installed. A description of this setup together with Monte Carlo results about its excellent capabilities in the precise determination of pulse arrival times are presented

Formulación del problema de optimización multiobjetivo del confort en edificación sostenible

XXXVII Jornadas de Automática. 07/09/2016. MadridEn este trabajo se realiza un análisis detallado del problema de optimización del confort desde un enfoque basado en criterios de edificación sostenible. Para ello, se propone una arquitectura de control jerárquico multicapa gobernada mediante una estrategia de optimización multiobjetivo que proporciona trayectorias de referencia para la temperatura del aire y la iluminancia en el interior de las estancias de un edificio. Los objetivos que se han establecido para el desarrollo de este trabajo son maximizar el confort térmico, el confort visual y la eficiencia energética.Ministerio de Economía y Competitividad DPI2014-56364-C2-1-

Control de plantas solares con generación automática de consignas

En este trabajo se muestran los resultados de operación de un campo de colectores solares del tipo cilindro parabólico de forma automática con una estructura de control por adelanto en paralelo con un controlador tipo I-PD que incorpora como principal novedad un sistema de generación automática de consignas. El objetivo de control para este sistema es mantener la temperatura del fluido a la salida del campo a un valor establecido, compensando las perturbaciones a las que está sometida la planta con dinámica fuertemente no lineal.Ministerio de Ciencia y Tecnología DPI2001-2380-C02Ministerio de Ciencia y Tecnología DPI2002-04375-C0

Study of fundamental control concepts through interactive learning objects

Information technology has contributed significantly to the renewal of teaching methodologies used in control systems teaching. Computer applications are becoming very popular as a support in traditional lectures and as self-learning tools. This paper describes an on-going project which tries to develop a suite of interactive learning objects composed by graphical interactive applications plus simple learning cards to cover the complete contents of an introductory control system course.Postprint (published version