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

A Systematic Two-Layer Approach to Develop Web-based Experimentation Environments for Control Engineering Education

This paper introduces the systematic approach currently used by the Department of Computer Science and Automatic Control of the Spanish University of Distance Learning (UNED) to develop Web-based laboratories for distance learning of topics with high technical contents such as control engineering. This approach differentiates two layers in the construction of web- based laboratories: the experimentation layer and the e-learning layer. For the experimentation layer, LabVIEW and data acquisition boards from National Instruments are used to create the server-side applications and Easy Java Simulations for the client-side interfaces. For the e-learning layer, the eMersion environment is used to support the required flexible educational scheme. This paper describes the programming techniques implemented and the design considerations that justify these particular choices. As an llustrative case-study, an example of development of a web-based application is discussed, in which an electrical drive servo-motor is introduced as a convenient setup to practice with motion control applications. Other significant examples of web-based experiments developed by the authors are also reported

New modelling technique for aperiodic-sampling linear systems

A general input-output modelling technique for aperiodic-sampling linear systems has been developed. The procedure describes the dynamics of the system and includes the sequence of sampling periods among the variables to be handled. Some restrictive conditions on the sampling sequence are imposed in order to guarantee the validity of the model. The particularization to the periodic case represents an alternative to the classic methods of discretization of continuous systems without using the Z-transform. This kind of representation can be used largely for identification and control purposes.Comment: 19 pages, 0 figure

Assessment of the application of enzymes in the production of sewage sludge in WWTP

Motivation: In the urban wastewater treatment plants (WWTP) a large volume of sewage sludge is produced due to the growth of microorganisms in the biological reactors. This sludge cannot spill directly to the environment, because it is legally forbidden (Directive 91/271/EEC). Nowadays, the searching of alternatives for treating/reducing this sludge is increasing. Some previous works [1] focused on different strategies for sewage sludge reduction in conventional activated sludge systems not interfering in the efficiency of the process. Among the different strategies, the use of hydrolytic enzymes seemed to be effective in the reduction of the excess sludge production (up to 30% reduction, [2]). On the other hand, the overgrowth of microorganisms and the accumulation of non-biodegradable organic matter in the filtering media of constructed wetlands produce the clogging and collapse of these natural treatment systems.The above mentioned problems could be mitigated if reducing the amount of refractory matter in the influent and limiting the growth of microorganisms by the use of enzymes’ technology. However, the application of enzymes is limited, mainly, by their high cost of acquisition. One alternative of commercial enzymes could be enzymes generated in the fermentation of sewage sludge or other by-products coming of WWTP [3]. This study aims at (1) the determination of the optimum conditions for the application of enzymes in the wastewater treatment and (2) the assessment of the effects on both intensive and extensive treatment systems.Methods: In this study, lab scale pilot plants are employed for the assessment of the application enzymes to biological reactors. One pilot plant works as an activated sludge system (intensive tech.) and the other will simulate a constructed wetland (extensive tech.). Both pilot plants are fed with real wastewater. Commercial enzymes will be tested initially, and later, with the by-product obtained in the fermentation of sewage sludge. Physicochemical and microbiological parameters will be monitored in both systems to assess the effect of enzyme’s addition on both systems. Besides, sludge production and “clogging” phenomena will be studied. According to the results of Lab scale tests, the study will continue extrapolating to a large- scale pilot plants, to verify the sewage sludge reduction and identify possible operative problems under real conditions

Technical committee on control education

Presents information of the CS society Presents information of the CS society Technical Committee on Control Education

An interactive approach to control systems analysis and design by the root locus technique

[EN] The root locus is a classic method for linear control systems analysis. Since its interruption in the fifties, it has been included in introductory undergraduate courses on control systems. The emergence of interactive control system design software tools, which easily draw the root locus, allows teachers to focus on explaining how the introduction of new poles/zeros in the openloop transfer function affects the root locus, instead of explaining its building rules. In this work, a new teaching methodology in presented to introduce the root locus technique in introductory courses on control systems that encourages the use of an interactive tool, such as the LCSD tool developed by the authors, to reinforce their learning.[ES] El lugar de las raíces es un método clásico para el análisis y diseño de sistemas lineales de control que ha formado parte desde su irrupción en los años cincuenta de los programas de los cursos básicos de control automático. La aparición de herramientas software de diseño interactivo de sistemas de control, que dibujan fácilmente el lugar de las raíces, permite a los docentes centrarse en explicar cómo afecta al lugar de las raíces la introducción de nuevos polos/ceros en la función de transferencia en lazo abierto, en vez de en explicar sus reglas de construcción. En este trabajo se presenta una nueva metodología docente para introducir la técnica del lugar de las raíces en cursos básicos de control que fomenta la utilización de una herramienta interactiva, como por ejemplo la herramienta LCSD desarrollada por los autores, para reforzar su aprendizaje.Este trabajo ha sido financiado por el Ministerio de Ciencia, Innovación y Universidades bajo los proyectos ECoDiC ref. RTI2018-094665-B-I00 y DOVELAR ref. RTI2018-096001-B-C32.Díaz, JM.; Costa-Castelló, R.; Dormido, S. (2021). Un enfoque interactivo para el análisis y diseño de sistemas de control utilizando el método del lugar de las raíces. Revista Iberoamericana de Automática e Informática industrial. 18(2):176-192. https://doi.org/10.4995/riai.2020.13811OJS176192182Arévalo, V., Vicente-del-Rey, J.M., García-Morales, I., Rivas-Blanco, I., 2020. Minivídeos tutoriales como apoyo al aprendizaje de conceptos básicos para un curso de Fundamentos de Control Automático. Revista Iberoamericana de Automática e Informática Industrial, 17, 107-115. https://doi.org/10.4995/riai.2020.12156Åström, K. J., Murray, R. M., 2014. Feedback Systems: An Introduction for Scientists and Engineers 2 nd Edition. Princeton University Press.Díaz, J. M., Dormido, S., Aranda, J., 2007. SISOQFTIT: An interactive software tool for robust control design using the QFT methodology, Int. J. Eng. Educ., 23, 5, 1011-1023.Díaz, J. M., Dormido, S., Rivera, D.E., 2016. ITTSAE: A set of interactive software tools for time series analysis education, IEEE Control Syst. Mag., 36, 3, 112-120. https://doi.org/10.1109/MCS.2016.2535914Díaz, J. M., Costa, R., Muñoz, R., Dormido, S., 2017. An interactive and comprehensive software tool to promote active learning in the loop shaping control system design. IEEE Access 5, 10533-10546. https://doi.org/10.1109/ACCESS.2017.2712520Dorf, R. C., Bishop, R. H., 2011. Modern Control Systems 12 th Edition. Prentice Hall.Dormido, S., Gordillo, F., Dormido-Canto, S., Aracil, J., 2002. An interactive tool for introductory nonlinear control systems education, Proc. IFAC 15th World Congress, 35, 1, 255-260. https://doi.org/10.3182/20020721-6-ES-1901.01433Dormido, S., 2004. Control learning: Present and future, Annu. Rev. Control, 28, 1, 115-136. https://doi.org/10.1016/j.arcontrol.2003.12.002Dormido, S., Dormido-Canto, S., Dormido-Canto, R., Sánchez, J., Duro, N., 2005. The role of interactivity in control learning,Int. J. Eng. Educ., 21, 6, 1122-1133.Evans, W. R., 1948. Graphical analysis of control systems. Transactions of the American Institute of Electrical Engineers 67, 547-551. https://doi.org/10.1109/T-AIEE.1948.5059708Evans, W. R., 1950. Control systems synthesis by root-locus method Transactions of the American Institute of Electrical Engineers 69, 66-69. https://doi.org/10.1109/T-AIEE.1950.5060121Evans, W. R., 1954. Control System Dynamics. McGraw-Hill, New York.Franklin, G. F., Powell, J. D., Emami-Naeini, A., 2015. Feedback Control of Dynamic Systems 7 th Edition. Pearson.Gasmi, H., Bouras, A., 2018. Ontology-based education/industry collaboration system, IEEE Access, 6, 1362-1371. https://doi.org/10.1109/ACCESS.2017.2778879Golnaraghi, F., Kuo, B. C., 2017. Automatic Control Systems 10 th Edition. McGraw-Hill.Guzmán, J. L., Åström, K. J., Dormido, S., Hagglund, T., Berenguel, M., Piguet, Y., 2008. Interactive learning modules for PID control,IFAC Proc. 39, 6, 7-12. https://doi.org/10.3182/20060621-3-ES-2905.00003Guzmán, J. L., Rivera, D. E., Dormido, S., Berenguel, M., 2012. An interactive software tool for system identification, Adv. Eng. Softw., 45, 115-123. https://doi.org/10.1016/j.advengsoft.2011.09.013Guzmán, J. L., Dormido, S., Berenguel, M., 2013. Interactivity in education: An experience in the automatic control field, Comput. Appl. Eng. Educ., 21, 2, 360-371. https://doi.org/10.1002/cae.20480Guzmán, J. L., Costa, R., Dormido, S., Berenguel, M., 2016. An interactivity based methodology as support to control education, IEEE Control Syst. Mag., 35, 1, 11-25.Keviczky, L., Bars, R., Hetthéssy, J., Bányász, C., 2019. Control Engineering. Springer. https://doi.org/10.1007/978-981-10-8297-9Lerma, E., Costa-Castelló, R., Griño Cubero, R., Sanchis, C., 2020. Herramientas para la docencia de control digital en grados de ingeniería, Revista Iberoamericana de Automática e Informática Industrial. [Online] https://polipapers.upv.es/index.php/RIAI/article/view/13756Moon, Y. L., 2007. Education reform and competency-based education, Asia Pacific Education Review, 8, 2, 337-341. https://doi.org/10.1007/BF03029267Nickerson, J. V., Corter, J. E., Esche, S. K., Chassapis, C., 2007. A model for evaluating the effectiveness of remote engineering laboratories and simulations in education, Computers & Education, 49, 3, 708- 725. https://doi.org/10.1016/j.compedu.2005.11.019Kasser, J., Hitchins, D., Frank, M., Zhao, Y. Y., 2013. A framework for benchmarking competency assessment models, Systems Engineering, 16, 1, 29-44. https://doi.org/10.1002/sys.21217Heradio, R., de la Torre, L., Dormido, S., 2016. Virtual and remote labs in control education: A survey, Annual Reviews in Control, 42, 1-10. https://doi.org/10.1016/j.arcontrol.2016.08.001Nise, N. S., 2015. Control Systems Engineering 7 th Edition. John Wiley and Sons.Ogata, K., 2010. Modern Control Engineering 5 th Edition. Prentice Hall.Piguet, Y., 2017. Sysquake 6 User Manual. Calerga, Lausanne.Vargas, H., Heradio, R., Chacon, J., de La Torre, L., Farias, G., Galan, D., Dormido, S., 2019. Automated Assessment and Monitoring Support for Competency-Based Courses, IEEE Access, 7, 41043-41051. https://doi.org/10.1109/ACCESS.2019.2908160Vargas, H., Marín, L., de la Torre, L., Heradio, R., Díaz, J. M., Dormido, S., 2020. Evidence-based control engineering education: evaluating theLCSD simulation tool, IEEE Access, 8, 170183-170194, 2020 https://doi.org/10.1109/ACCESS.2020.302391

Overview of JET Results

AbstrAct Recent advances in data mining allow the automatic recognition of physical phenomena in the databases of fusion devices without human intervention. This is important to create large databases of physical events (thereby increasing the statistical relevance) in an unattended manner. Important examples are the L/H and H/L transitions. In this contribution, a novel technique is introduced to automatically locate H/L transitions in JET by using conformal predictors. The focus is on H/L transitions because typically there is not a clear signature in the time series of the most widely available signals to recognize the change of confinement. Conformal predictors hedge their prediction by means of two parameters: confidence and credibility. The technique has been based on binary supervised classifiers to separate the samples of the respective confinement modes. Results with several underlying classifiers are presented

A survey of good practice in control education

This paper gives a focussed summary of good practice taken primarily from engineers who are responsible for teaching topics related to systems and control. This engineering specialisation allows the paper to give some degree of focus in the discussions around laboratories, software and assessment, although naturally many of the conclusions are generic. A key intention is to provide a summary document or survey paper which can be used by academics as a start point in studies of what is effective in the discipline. It is also hoped that such a summary will will be useful to engineering institutions in drawing together and disseminating open access resources that are freely available to the community at large

Idiopathic Adolescent Scoliosis and self-concept

Introducción y objetivos. Esta investigación trata sobre adolescentes que presentan escoliosis idiopática. Queremos estudiar si la manifestación de tal patología tiene efectos psicológicos en el adolescente que la presenta y sobre todo en la imagen que percibe de sí mismo como de su entorno. El objetivo del presente estudio se concreta en conocer la influencia de la escoliosis idiopática en el autoconcepto o imagen de si mismo en el adolescente. Material y métodos. Estudio observacional. Muestra formada por 17 adolescentes de 10-18 años de edad. En primer lugar, al tratarse de menores de edad y con el fin de informar de las características del estudio, como de la participación en el mismo, se le pasó un consentimiento informado a los padres o tutores. Asimismo, se extrajeron una serie de datos biográficos para identificar aspectos como el perfil clínico y personal, diagnóstico, antecedentes familiares, datos personal y de ocio del paciente, a través de un cuestionario de datos biográficos. Finalmente se le pasó el cuestionario de Pierre-Harris que consta de 80 ítems que abarcan las siguientes dimensiones del concepto de si mismo: comportamiento, estatus general y académico, popularidad, felicidad y satisfacción, apariencia física, ansiedad. Tras la recogida de los datos, se realizó un análisis de distribución de frecuencias, mediante el método estadístico SPSS v. 15.0 para Windows, con el cálculo de la media y la desviación típica, de los mismos. Resultados. Las puntuaciones del cuestionario de Pierre-Harris por cada sujeto, están por encima de la media establecida en cada dimensión. Solamente, en la dimensión de ansiedad, hay 5 sujetos por debajo de la media. Conclusiones. No se observó una imagen de sí mismo negativa o por debajo de la media en la muestra estudiada en ninguna dimensión del cuestionario. Solamente una de las dimensiones presentaba algunos individuos por debajo, por lo tanto, en la muestra estudiada con escoliosis idiopática del adolescente, la imagen de sí mismo es buena, por los valores encontrados.Terapia y Rehabilitació