Asymptotic rejection of sinusoidal disturbances based voltage balance control in back-to-back power converters

This paper addresses the imbalance problem of the dc-link capacitor voltages in the three-level diode-clamped back-to-back power converter. In order to cope with it, a mathematical analysis of the capacitor voltage difference dynamics, based on a continuous model of the converter, is first carried out. It leads to an approximated model which contains explicitly several sinusoidal functions of time. In view of this result, the voltage imbalance phenomenon can be addressed as an output regulation problem, considering the sinusoidal functions as exogenous disturbances. Thus, a novel approach to deal with the mentioned problem in the back- to-back converter is presented. Then, the particular features of the disturbances are used to design several controllers. They all follow an asymptotic disturbance rejection approach. In this way, the estimations of the disturbances are used to apply a control law that cancels them while regulating the capacitor voltage balance as well. Finally, the performance of the proposed control laws is evaluated, presenting the simulation results obtained when the different controllers are implemented.MICINN-FEDER DPI2009-0966

Automated generation of control design benchmark problems for computer-assessed education with Doctus

[ES] En este trabajo se presenta una aplicación que permite a un profesor generar de forma automática ejercicios de diseño de controladores para sistemas lineales para la plataforma de e-learning Doctus. Doctus es una aplicación que permite automatizar la recogida, almacenamiento y evaluación de ejercicios de contenido científico-técnico. En general, para utilizar Doctus es necesario escribir scripts de MATLAB, tanto para la evaluación automàtica de la respuesta de los alumnos como para la generación de enunciados personalizados. La aplicación que se presenta es una extensión de Doctus destinada a simplificar este trabajo, permitiendo generar ejercicios personalizados mediante la aplicación de un escalado temporal y de ganancia a partir de un problema semilla que proporciona el profesor. La aplicación presentada resuelve, por lo tanto, dos problemas: primero el de facilitar el uso de Doctus a profesores no expertos, y segundo el de proporcionar a cada estudiante un ejercicio individualizado[EN] This paper presents an application that enables the teacher to automatically generate control design exercises for linear systems for the Doctus e-learning platform. Doctus is an application that automates the collection, storage and evaluation of scientific and technical education exercises. In general, the use of Doctus requires writing MATLAB scripts, both for the automatic evaluation of student responses and for the generation of personalized wordings. The application presented is an extension of Doctus designed to simplify this work, allowing the generation of personalized exercises by applying time and gain scalings based on a seed problem provided by the teacher. As a consequence, the application presented solves two problems: first, to facilitate the use of Doctus to non-expert teachers, and second, to provide each student with an individualized exercise with guaranteed solution and equal diffculty.Asimismo desean agradecer la ayuda otorgada por el Vicerrectorado de investigación de la Universidad Loyola Andalucía. Este trabajo se ha financiado parcialmente con los proyectos DPI2016-75294-C2-2-R y DPI2016-76493-C3-1-R.Sánchez, C.; Muñoz De La Peña, D.; Gómez-Estern, F. (2020). Generación automática de problemas de diseño de controladores para sistemas lineales autoevaluables con Doctus. Revista Iberoamericana de Automática e Informática industrial. 17(1):1-9. https://doi.org/10.4995/riai.2019.11243OJS19171Ala-Mutka, K. M., 2005. A survey of automated assessment approaches for programming assignments. Computer Science Education 15 (2), 83-102. https://doi.org/10.1080/08993400500150747Ayas, M. S., Altas, I. H., 2016. A virtual laboratory for system simulation and control with undergraduate curriculum. Computer Applications in Engineering Education 24 (1), 122-130. https://doi.org/10.1002/cae.21678Cerezo, F., Sastrón, F., 2015. Laboratorios virtuales y docencia de la automática en la formación tecnológica de base de alumnos preuniversitarios. Revista Iberoamericana de Automática e Informática industrial 12 (4), 419-431. https://doi.org/10.1016/j.riai.2015.04.005Chih-Ming, C., Hahn-Ming, L., Ya-Hui, C., 2005. Personalized e-learning system using item response theory. Computers & Education 44 (3), 237-255. https://doi.org/10.1016/j.compedu.2004.01.006Dorf, R., Bishop, R., 2005. Sistemas de Control Moderno 10Ed. Pearson, Inglaterra.Douce, C., Orwell, J., Livingstone, D., 2005. Automatic test-based assessment of programming: A review. ACM Journal of Educational Resources in Computing 5 (3). https://doi.org/10.1145/1163405.1163409Guzmán, J., Costa, R., Berenguel, M., Dormido, S., 2012. Control automático con herramientas interactivas. Pearson, Inglaterra.Gómez-Estern, F., López-Martínez, M., Muñoz de la Peña, D., 2010. Sistemas de evaluación automática vía web en asignaturas prácticas de ingeniería. Revista Iberoamericana de Automática e Informática Industrial 7 (3), 111-119. https://doi.org/10.4995/RIAI.2010.03.10López-Martínez, M., Gómez-Estern, F., Muñoz de la Peña, D., 2010. Automatic web-based evaluation of C-programming exercises in engineering education. International Journal for Knowledge, Science and Technology 1 (2), 1-6.Martínez, J., Padilla, A., Rodríguez, E., Jiménez, A., Orozco, H., 2017. Diseño de herramientas didácticas enfocadas al aprendizaje de sistemas de control utilizando instrumentación virtual. Revista Iberoamericana de Automática e Informática industrial 14 (4), 424-433. https://doi.org/10.1016/j.riai.2017.03.003Mendez, J. A., Gonzalez, E. J., 2011. Implementing motivational features in reactive blended learning: Application to an introductory control engineering course. IEEE Transactions on Education 54 (4), 619-627. https://doi.org/10.1109/TE.2010.2102028Méndez, J. A., González, E. J., 2013. A control system proposal for engineering education. Computers & Education 68, 266-274. https://doi.org/10.1016/j.compedu.2013.05.014Méndez, J. A., Lorenzo, C., Acosta, L., Torres, S., González, E., 2006. A webbased tool for control engineering teaching. Computer Applications in Engineering Education 14 (3), 178-187. https://doi.org/10.1002/cae.20080Muñoz de la Peña, A., González-Gómez, D., Muñoz de la Peña, D., Gómez-Estern, F., Sánchez, M., 2012a. Automatic web-based grading system: Application in an advanced instrumental analysis chemistry laboratory. Journal of Chemical Education 90, 308-314. https://doi.org/10.1021/ed3000815Muñoz de la Peña, D., Gómez-Estern, F., Dormido, S., 2012b. A new internet tool for automatic evaluation in control, systems and programming. IEEE Computers & Education 59, 535-550. https://doi.org/10.1016/j.compedu.2011.12.016Ogata, K., 2011. Ingenier'ıa de Control Moderna 5ED. Pearson, Inglaterra.Pieterse, V., 2005. Automated assessment of programming assignments. Computer Science Education Research Conference.Prados, F., Boada, I., Soler, J., Poch, J., 2005. Automatic generation and correction of technical exercises. International Conference on Engineering and Computer Education.Ruano Ruano, I., Gámez García, J., Gómez Ortega, J., 2016. Laboratorio web scorm de control pid con integración avanzada. Revista Iberoamericana de Automática e Informática industrial 13 (4), 472-483. https://doi.org/10.1016/j.riai.2016.05.007Sánchez-Alonso, R. E., Ortega-Moody, J., González-Barbosa, J. J., Reyes-Morales, G., 2017. Uso de plataformas para el desarrollo de aplicaciones virtuales en el modelado de robot manipuladores. Revista Iberoamericana de Automática e Informática industrial 14 (3), 279-287. https://doi.org/10.1016/j.riai.2017.04.001Tartaglia, A., Tresso, E., 2002. An automatic evaluation system for technical education at the university level. IEEE Transactions on Education 45 (3), 268-275. https://doi.org/10.1109/TE.2002.1024620Valera, A., Soriano, A., Vallés, M., 2014. Plataformas de bajo coste para la realización de trabajos prácticos de mecatrónica y robótica. Revista Iberoamericana de Automática e Informática industrial 11 (4), 363-376. https://doi.org/10.1016/j.riai.2014.09.00

Doctus, una herramienta de e-learning innovadora para educación en automática y áreas afines

[Resumen] En este trabajo se presenta una nueva herramienta para su uso en docencia en asignaturas del área de Ingeniería de Sistemas y Automática, y por extensión en cualquier materia científico-técnica. Doctus es una versión completamente renovada de Goodle GMS, una aplicación que en los últimos años ha cobrado relevancia en entornos académicos con la que se ha tratado de llevar el concepto de evaluación automática mucho más allá de los paradigmas tradicionales recogidos en Moodle y herramientas afines. La extensa base de datos de ejercicios creados hasta la actualidad en Goodle y compatibles con el nuevo Doctus, permite un acceso rápido a las funcionalidades de autocorrección. Además de presentar una arquitectura software modular orientada a objetos y una interfaz mejorada, Doctus posee una serie de características innovadoras que resultan de interés práctico en el área de Automática.https://doi.org/10.17979/spudc.978849749808

Modelado de micro-central hidráulica para el diseño de controladores con aplicación en regiones aisladas de Honduras

[Resumen] Este artículo trata el modelado de una planta de micro-generación destinada al abastecimiento eléctrico de regiones aisladas en países en vías de desarrollo. El objetivo del modelo es caracterizar fielmente el comportamiento de estas microcentrales ante acciones externas como la actuación sobre la válvula de admisión y la conexión o desconexión repentina de cargas. Este modelo permitirá el desarrollo de estrategias de control eficientes, robustas y sencillas, adaptadas al contexto de precariedad de este tipo de instalaciones.Ministeriro de Economía y Competitividad ; DPI-75294-CS-2-RMinisterio de Economía y Competitividad; TEC2016-80242-

Physical damping in IDA-PBC controlled underactuated mechanical systems: Special issue on Hamiltonian and Lagrangian Methods for Nonlinear Control

Energy shaping and passivity-based control designs have proven to be effective in solving control problems for underactuated mechanical systems. In recent works, Interconnection and Damping Assignment Passivity-Based Control (IDA-PBC) has been successfully applied to open loop conservative models, i.e. with no physical damping (e.g., friction) present. In a number of cases, in particular when IDA-PBC control only involves potential energy shaping, the actual presence of physical damping will not compromise the achieved closed-loop stability. However, when IDA-PBC control also includes the shaping of the kinetic energy, closed-loop stability or even passivity for the model without physical damping may be lost if physical damping is present. This raises two fundamental questions. First, in which cases is the IDA-PBC controlled system designed on the basis of the undamped model still stable and passive when physical damping is present? Secondly, if this is not the case, when is it possible to redesign the IDA-PBC control law for the undamped systems such that stability and passivity are regained? This paper provides necessary and sufficient conditions for the existence of such a control redesign for a particular choice of the closed loop energy function. Furthermore, if these conditions are satisfied then two methods for redesign are presented, which can be chosen depending on the problem structure and the parameter uncertainties. Finally, even in the cases where the addition of physical damping does not hamper the stability properties of the IDA-PBC design based on the undamped model, we show that the aforementioned redesign is still useful in order to reduce the mathematical complexity in exponential and asymptotic stability analysis

Physical damping in IDA-PBC controlled underactuated mechanical systems

Energy shaping and passivity-based control designs have proven to be effective in solving control problems for underactuated mechanical systems. In recent works, Interconnection and Damping Assignment Passivity-Based Control (IDA-PBC) has been successfully applied to open loop conservative models, i.e. with no physical damping (e.g., friction) present. In a number of cases, in particular when IDA-PBC control only involves potential energy shaping, the actual presence of physical damping will not compromise the achieved closed-loop stability. However, when IDA-PBC control also includes the shaping of the kinetic energy, closed-loop stability or even passivity for the model without physical damping may be lost if physical damping is present. This raises two fundamental questions. First, in which cases is the IDA-PBC controlled system designed on the basis of the undamped model still stable and passive when physical damping is present? Secondly, if this is not the case, when is it possible to redesign the IDA-PBC control law for the undamped systems such that stability and passivity are regained? This paper provides necessary and sufficient conditions for the existence of such a control redesign for a particular choice of the closed loop energy function. Furthermore, if these conditions are satisfied then two methods for redesign are presented, which can be chosen depending on the problem structure and the parameter uncertainties. Finally, even in the cases where the addition of physical damping does not hamper the stability properties of the IDA-PBC design based on the undamped model, we show that the aforementioned redesign is still useful in order to reduce the mathematical complexity in exponential and asymptotic stability analysis.

A qualitative community health assessment of HIV prevention awareness in a semi-rural Latinx seasonal farm working community in South Florida

This article explores HIV awareness and prevention in a Latinx seasonal farmworker community of south Miami-Dade County in the USA. The study took place as part of a larger community assessment that aimed to determine community needs and resources related to substance abuse, violence and HIV in the Latinx seasonal farmworker communities of south Miami-Dade County, with a particular focus on fathers' and their male sons' relationships. The study collected data on HIV knowledge and prevention, healthcare-seeking behaviours, cultural norms, and communication barriers about HIV prevention between fathers and sons. Data were collected through in-depth interviews with community leaders, two focus groups with social and health services providers, and four focus groups involving fathers and their adolescent sons. A deductive approach to data analysis was undertaken. Five major themes were identified: (1) HIVrelated knowledge and perception; (2) HIV prevention strategies; (3) barriers and needs for tailored preventive health and care services in the community; (4) stress over sex-related communication; and (5) the dominance of traditional masculine gender norms in the household and the community

Automatic Web-Based Grading System: Application in an Advanced Instrumental Analysis Chemistry Laboratory

The application of an innovative Web-based system, Goodle GMS, designed for automating the collection and assessment of laboratory exercises is presented. This Web-based system has been extensively used in engineering courses such as control systems, mechanics, and computer programming. Goodle GMS allows the students to submit their results to a server via a Web-based form from any networked computer and receive their grade, feedback, and an indication of where mistakes may have been made. To design new exercises, basic Matlab knowledge is required. As an example, we describe the development and application of Goodle GMS in an advanced analytical chemistry laboratory to determine the nitrite concentration in water samples by using a flow injection analysis (FIA) system, with photometric detection, based on the Griess reactio