Abstract
Nowadays, in industrial control applications, is rather usual to sample and update different variables at different rates, although it is common to consider all these activities equally and regularly spaced on time. These applications are implemented on real-time operating systems by decomposing them into several tasks in such a way that pre-emption and blocking may appear due to task priorities and resource sharing. This could imply the presence of delays, leading to a non-regular periodic behaviour and, as a result, the control performance can be degraded. In order to undertake this problem, a solution based on a modelling methodology for non-conventional sampled-data systems is proposed. This technique permits the consideration of any cyclic sampling pattern. Thus, these delays can be considered in the modelling step, and later on, a non-conventional controller based on this model can be designed. In this way, if the considered non-conventional control system is implemented assuming a real-time operating system (Tornado-VxWorks, in this case), a clear performance improvement can be observed.
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Ángel Cuenca was born in Valencia (Spain) in 1974. He received his M.Sc. degree in Computer Science in 1998 and his Ph.D. in Control Engineering in 2004, from the Polytechnic University of Valencia. He is with the department of Systems Engineering and Control at the Polytechnic University of Valencia. He has been teaching courses on systems theory, programmable logic controllers and multi-rate sampled-data systems. His research interests include non-conventionally sampled-data systems and networked based control systems. He has taken part in several national and European research projects.
Julian Salt was born in Valencia, Spain in 1960. He received his M.Sc. degree in industrial engineering in 1986 and his Ph.D. in Control Engineering in 1992, from Valencia Polytechnic University. His current position is as Professor of Automatic Control (2000-), Valencia Polytechnic University (UPV), teaching a wide range of subjects in the area from continuous and discrete simulation to automation and programmable logic controllers applications. His research interests include non-conventionally sampled control systems and networked based control systems. He has taken part in research projects funded by local industries, government and the European Science Foundation. He has also been involved in educational projects and currently is Head of the Systems Engineering and Control Department at UPV. He has been director of 8 PhD thesis and coauthor of about 60 technical papers in journals and technical meetings.
Pedro Albertos, full Professor since 1975, currently at the Dept of Systems Engineering and Control at the Polytechnic University of Valencia, Spain. He has been Director from 1979 to 1995 and in 1998. He has been teaching courses on Advanced Control Systems, Intelligent Control Systems and Systems Theory. He is Honorary Profesor at the Northwestern University, Senhyang, China and Doctor Honoris Causa at the Universities of Oulu (Finland) and Polytechnic of Bucarest (Rumania). Invited Professor in more than 20 Universities, all around the world, he has delivered seminars in more than 30 universities and research centres. Authored more than 300 papers, book chapters and congress communications, he is co-editor of 7 books and co-author of Multivariable Control Systems (Springer 2004). He has directed 16 PhD thesis, and he is the coordinator of the PhD Program on Automatica and Industrial Informatics, which has been implemented in Spain, Mexico, Columbia and Venezuela. He has participated in many national and international research projects. Currently is involved in the ARTIST2 Node of Excellence on Embedded Control Systems. He is associated editor of Control Engineering Practice and Automatica and editor in chief of the journal Revista RIAI (Revista Iberoamericana de Automática e Informática Industrial). In the period 1999–2002 he was the IFAC President.
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Cuenca, Á., Salt, J. & Albertos, P. Implementation of algebraic controllers for non-conventional sampled-data systems. Real-Time Syst 35, 59–89 (2007). https://doi.org/10.1007/s11241-006-9001-2
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DOI: https://doi.org/10.1007/s11241-006-9001-2