Computationally efficient min-max MPC

2005 IFAC 16th Triennial World Congress, Prague, Czech RepublicMin-Max MPC (MMMPC) controllers (Campo and Morari, 1987) suffer from a great computational burden that is often circumvented by using upper bounds of the worst possible case of a performance index. These upper bounds are usually computed by means of LMI techniques. In this paper a more efficient approach is shown. This paper proposes a computationally efficient MMMPC control strategy in which the worst case cost is approximated by an upper bound which can be easily computed using simple matrix operations. This implies that the algorithm can be coded easily even in non mathematical oriented programming languages such as those found in industrial embedded control hardware. Simulation examples are given in the paper

Computational burden reduction in Min-Max MPC

Min–max model predictive control (MMMPC) is one of the strategies used to control plants subject to bounded uncertainties. The implementation of MMMPC suffers a large computational burden due to the complex numerical optimization problem that has to be solved at every sampling time. This paper shows how to overcome this by transforming the original problem into a reduced min–max problem whose solution is much simpler. In this way, the range of processes to which MMMPC can be applied is considerably broadened. Proofs based on the properties of the cost function and simulation examples are given in the paper

Min-Max Predictive Control of a Pilot Plant using a QP Approach

47th IEEE Conference on Decision and Control 9-11 Dec. 2008The practical implementation of min-max MPC (MMMPC) controllers is limited by the computational burden required to compute the control law. This problem can be circumvented by using approximate solutions or upper bounds of the worst possible case of the performance index. In a previous work, the authors presented a computationally efficient MMMPC control strategy in which a close approximation of the solution of the min-max problem is computed using a quadratic programming problem. In this paper, this approach is validated through its application to a pilot plant in which the temperature of a reactor is controlled. The behavior of the system and the controller are illustrated by means of experimental results

Min–max MPC using a tractable QP problem

Min–max model predictive controllers (MMMPC) suffer from a great computational burden that is often circumvented by using approximate solutions or upper bounds of the worst possible case of a performance index. This paper proposes a computationally efficient MMMPC control strategy in which a close approximation of the solution of the min–max problem is computed using a quadratic programming problem. The overall computational burden is much lower than that of the min–max problem and the resulting control is shown to have a guaranteed stability. A simulation example is given in the paper

Min-Max MPC based on a computationally efficient upper bound of the worst case cost

Min-Max MPC (MMMPC) controllers [P.J. Campo, M. Morari, Robust model predictive control, in: Proc. American Control Conference, June 10–12, 1987, pp. 1021–1026] suffer from a great computational burden which limits their applicability in the industry. Sometimes upper bounds of the worst possible case of a performance index have been used to reduce the computational burden. This paper proposes a computationally efficient MMMPC control strategy in which the worst case cost is approximated by an upper bound based on a diagonalization scheme. The upper bound can be computed with O(n3) operations and using only simple matrix operations. This implies that the algorithm can be coded easily even in non-mathematical oriented programming languages such as those found in industrial embedded control hardware. A simulation example is given in the paper

Min-max model predictive control as a quadratic program

This paper deals with the implementation of min-max model predictive control for constrained linear systems with bounded additive uncertainties and quadratic cost functions. This type of controller has been shown to be a continuous piecewise affine function of the state vector by geometrical methods. However, no algorithm for computing the explicit solution has been given. In this paper, we show that the min-max optimization problem can be expressed as a multi-parametric quadratic program, and so, the explicit form of the controller may be determined by standard multi-parametric techniques

A Java based simulation for basic control

7th IFAC Symposium on Advances in Control Education 21/06/2006 MadridIn this paper we present a java based simulator for control education in basiccourses. The application has been developed using the well known tool Easy JavaSimulation.The objective of the application is to help the student to learn the design of classiccontrollers such as P,PI, PID, etc testing the tuning procedures to control the position ofan antenna controlled by a DC motor. Thus the application allows the student to choosethe parameters of the antenna and the DC motor, to choose the controller to be used andits parameters and finally to simulate the closed loop system observing the evolution ofthe signals as well as a 3-D view. Furthermore, in order to show the real behavior of thesystem, dead zone, saturation, disturbances and non-linearities can be added to the model.This application has been used by the authors to teach a basic control course at EscuelaSuperior de Ingenieros (University of Seville) as virtual laboratory.Moreover, since the application is java based, this can be used by the students from theauthors’ web pages and this can also be installed in the student’s laptop (whichever theplatform is) by downloading it from the authors web page (Limon and Salas, 2003Ministerio de Ciencia y Tecnología DPI2004-07444Ministerio de Ciencia y Tecnología DPI2003-0042

Aproximación a un análisis pragmático del refrán: dimensión argumentativa

El artículo muestra un acercamiento al análisis pragmático del refrán. Describe algunos rasgos de este tipo de paremia que pueden catalogarse como pertenecientes al discurso argumentativo y que pueden aplicarse didácticamente en la clase de Lengua Castellana y Literatura. En la primera parte, introduce un breve análisis del refrán inscrito en una teoría de los actos de habla; en la segunda parte, propone algunas actividades que asumen el refrán como pretexto para el desarrollo de procesos de argumentación en los estudiantes de Lengua Castellana y Literatura.This article shows an approach to the pragmatic analysis of the proverb. It describes some aspects of this kind of saying that can be considered as part of the argumentative discourse and that might been used didactically in the Spanish class and literature. In the first part, it introduces a brief analysis of the proverb circumscribed in a speech acts theory; in the second part, it proposes some activities which assume the proverb as an excuse for the development of argumentation processes of the Spanish language and literature students

Propriedades psicométricas de uma escala para medir a gestão da vergonha em adolescentes (Moss-Sast)

(Ahmed, 1999) to measure shame management in adolescents in situations of aggression toward peers. The study was conducted with a sample of 700 students from public secondary schools (N= 700) located in a northwestern state municipality of Mexico. Results enabled to obtain an empirically sustainable measuring model formed by two factors: Acknowledgment and Displacement (X2 = 5.16, p= 0.27; CMIN= 1.29; GFI= .98; CFI= .99; NFI= .97; RMSEA= .05). Evidence was obtained to show that the instrument has criterion validity since it is capable to differentiate between subgroups of students with and without reports of bullying in both factors, Acknowledgment (t= 3.49, gl= 137, p< .001) and Displacement (t= 3.63, gl= 137, p< .001). It was concluded that the results strengthen the original factorial structure of the scale and show the usefulness of the same, both for inquiring about emotions related to moral development and for identifying students involved as aggressors in bullying situations.Se establecieron las evidencias de validez y confiabilidad de la adaptación del cuestionario MOSS-SAST (Ahmed, 1999) para medir el manejo de la vergüenza en adolescentes ante situaciones de agresión hacia los pares. El estudio se realizó en una muestra de estudiantes de escuelas secundarias públicas (N= 700) ubicadas en un municipio de un estado del noroeste de México. Los resultados permitieron obtener un modelo de medición empíricamente sustentable formado por nueve ítems agrupados en dos factores: Reconocimiento y Desplazamiento (c2 = 5.16, p= 0.27; CMIN= 1.29; GFI= .98; CFI= .99; NFI= .97; RMSEA= .05). El instrumento cuenta con evidencias de validez de criterio, ya que establece la diferencia en los factores de reconocimiento (t= 3.49, gl= 137, p< .001) y desplazamiento (t= 3.63, gl= 137, p< .001) en subgrupos de estudiantes con y sin reportes de bullying. Se concluyó que los resultados fortalecen la estructura factorial original de la escala y muestran su utilidad, tanto en la indagación de emociones relacionadas con el del desarrollo moral, como en la identificación de estudiantes involucrados como agresores en situaciones de bullying.Foram estabelecidas as evidências de validade e confiabilidade da adaptação do Questionário MOSS-SAST (Ahmed, 1999) para medir a gestão da vergonha em adolescentes ante situações de agressão contra os pares. O estudo foi realizado com uma amostra de estudantes do ensino fundamental e médio (N=700) de um município do noroeste do México. Os resultados permitiram obter um modelo de medição empiricamente sustentável, formado por nove itens agrupados em dois fatores: reconhecimento e deslocamento (c2 = 5.16, p= 0.27; CMIN= 1.29; GFI= .98; CFI= .99; NFI= .97; RMSEA= .05). O instrumento conta com evidências de validade de critério já que estabelece a diferença nos fatores de reconhecimento (t= 3.49, gl= 137, p< .001) e deslocamento (t= 3.63, gl= 137, p< .001) em subgrupos de estudantes com e sem relatos de bullying. Conclui-se que os resultados fortalecem a estrutura fatorial original da escala e mostram sua utilidade, tanto na indagação de emoções relacionadas com o desenvolvimento moral quanto na identificação de estudantes envolvidos como agressores em situações de bullying

Teorías o modelos de producción de textos en la enseñanza y el aprendizaje de la escritura

Este artículo presenta las teorías o modelos de escritura predominantes en la investigación educativa sobre comprensión y producción de textos. La mayoría de los modelos destaca, en mayor o menor grado, los factores culturales, sociales, afectivos, cognitivos, metacognitivos, discursivos, pragmáticos, entre otros, que intervienen en el proceso de producción textual. Este trabajo recoge y analiza los anteriores aspectos en función del diseño y aplicación de estrategias didácticas que contribuyan a favorecer la enseñanza y el aprendizaje de la escritura como proceso y como producto.Some predominant writing theories in the area of educational research about text comprehension and production are presented in this article. Most of these theories emphasize cultural, social, affective, cognitive, metacognitive, discourse, and pragmatic factors that intervene in the process of discourse production. In this article we analyze the previous in relation to the design and applications of some teaching strategies which contribute to improve the teaching and learning of writing both as a process and a product